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#1
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prog. therm. and heat pump questions
27. Rod Speed
Dec 16, 3:47 pm show options Newsgroups: alt.home.repair, sci.engr.heat-vent-ac, misc.consumers.frugal-living From: "Rod Speed" - Find messages by this author Date: Sat, 17 Dec 2005 07:47:00 +1100 Subject: prog. therm. and heat pump questions Reply | Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse Abby Normal wrote When it is sized to the load the problem is it would only shut off for an hour or two as the house cooled, then it would run steady until after the sun came up to catch up. No real point in setting back. That is just plain wrong. The whole point of a set back is that less is pumped at the setback temp because the losses are lower. How much lower depends on how well insulated the house is. The whole point of set back is to lower the temperature for a while.This would imply that the house cools down and the systems stops running during this cool down period. Then it would run less per hour due to the setback indoor temperature until such a time that it need to start warming up the house so that it was back up to temperature perhaps when the occupants awoke or perhaps returned home from work. The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong just unsucessful in educating you. All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Plus all the ductwork and backdraft dampers. Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Noah er I mean Nick is a bad influence on you. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. |
#2
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prog. therm. and heat pump questions
Abby Normal wrote
Rod Speed wrote Abby Normal wrote When it is sized to the load the problem is it would only shut off for an hour or two as the house cooled, then it would run steady until after the sun came up to catch up. No real point in setting back. That is just plain wrong. The whole point of a set back is that less is pumped at the setback temp because the losses are lower. How much lower depends on how well insulated the house is. The whole point of set back is to lower the temperature for a while. To reduce the amount of energy consumed to keep it at the higher temp. This would imply that the house cools down and the systems stops running during this cool down period. Correct. Then it would run less per hour due to the setback indoor temperature until such a time that it need to start warming up the house so that it was back up to temperature perhaps when the occupants awoke or perhaps returned home from work. Correct. The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Wrong with the situation being discussed, with more than one system so it doesnt take a long time to get it up to the normal temp again. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. And what was being discussed was having more than one system and doing that so it doesnt take a long time to get back to the normal temp and doesnt use the heat strips to do that. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong Yep, completely wrong. just unsucessful in educating you. You cant even keep track of what was actually being discussed. All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Yep, I mentioned 3 for a reason. Plus all the ductwork and backdraft dampers. You dont have to duplicate/triplicate all of those. Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Wasnt doing anything like that. Noah er I mean Nick is a bad influence on you. Nothing to do with Nick at all. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. Two and three was what was being discussed. Your claim that setback has no value is just plain wrong with THAT situation. |
#3
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prog. therm. and heat pump questions
If you installed two complete heat pumps to save on and speed recovery,
the added cost of the second system would be more than the savings provided by not using any strip heat. If you installed a slightly oversized 2 stage heat pump, it would run in low stage all summer providing about 65% total cooling capacity. Then it would run in high stage (High Capacity) during heating season when it was below 45 degrees outside. You could possibly set back in this case. Note that installing a two stage heat pump usually adds about $2,000.00 to an average installation. The average life of a quality, properly installed air to air heat pump is 15-20 years nationally. If you would save $2,000.00 over that time span, then install the two stage system. If you install two complete systems, add about $6000.00 to $10,000.00 to the cost of the first system, assuming you had room for the extra ducts and registers and equipment. Tough way to save money. Like going around your elbow to get to your asshole. (Or is it the other way around:-)? ). Strretch |
#4
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prog. therm. and heat pump questions
Stretch wrote:
If you installed two complete heat pumps to save on and speed recovery, the added cost of the second system would be more than the savings provided by not using any strip heat. Yes, that's why I said it would only make sense if the extra was surplus etc. If you installed a slightly oversized 2 stage heat pump, it would run in low stage all summer providing about 65% total cooling capacity. Then it would run in high stage (High Capacity) during heating season when it was below 45 degrees outside. You could possibly set back in this case. Note that installing a two stage heat pump usually adds about $2,000.00 to an average installation. The average life of a quality, properly installed air to air heat pump is 15-20 years nationally. If you would save $2,000.00 over that time span, then install the two stage system. If you install two complete systems, add about $6000.00 to $10,000.00 to the cost of the first system, assuming you had room for the extra ducts and registers and equipment. You wouldnt need all the ducts and registered duplicated if you just used it for the faster return from the setback temp. Tough way to save money. Yes, that's why I said it would only make sense if the extra was surplus etc. |
#5
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prog. therm. and heat pump questions
Stretch wrote:
... If you installed a slightly oversized 2 stage heat pump, it would run in low stage all summer providing about 65% total cooling capacity. Then it would run in high stage (High Capacity) during heating season when it was below 45 degrees outside. You could possibly set back in this case... That makes sense. Then again heat strips have their place. It isn't hard to think of a situation where they would save money (assuming net.thought.police still allow thinking), eg in a house with lots of heat loss and little thermal mass and a wimpy heat pump, eg 1000 Btu/h-F and 1000 Btu/F and a (70-30)1000 = 40K Btu/h heat pump on a 30 F night. If the heat pump can only keep up with a 40 F temp diff, no setback is possible, so a 10 hour night requires 400K Btu of heat, or 200K Btu of electrical energy with a COP of 2. With heat strips, the house can be 50 F most of the night, with 100K Btu of heat pump electrical energy and 1000Btu/F(70-50) = 20K Btu of 8 AM strip energy, so the strips save 80K Btu, ie 23 kWH of electrical energy, and the low-cap heat pump is cheaper. a two stage heat pump usually adds about $2,000.00 to an average installation. Why not a single-speed compressor with low and high airflows? Nick |
#6
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prog. therm. and heat pump questions
Nick,
If you check the data, or measure it yourself, Strips cost 2 to 3.5 times as much per BTU as the heat pump. So you set back by shutting off the cheap heat (Heat Pump Compressor), and recover by using the expensive strip heat. Setback increases the electric bill if the heat strips come on during recovery. In addition to warming the air during recovery, you also have to warm the entire thermal mass of the house and all it's contents. THAT is ia big part of the added power consumption. Here in Myrtle Beach, SC, a lot of homeowners are relocated yankees (like me), used to setback. They setback in the winter and their electric bills go up. They call me to check their system, I explain proper operation, they stop using setback in the winter and their electric bill goes back down. Happens every winter, many times. Many heat pump setback thermostats lock out strips during the beginning of setback recovery. On those, recovery takes a LONG time. After a number of hours, the strips are allowed back on, recovery occurs and electric bill goes up. Note that recovery without strips only works in mild weather, so setback efficiency depends on your climate. It does not work well in my climate. By the way, my wife, like many women, has to make several potty trips to pee every night. If I installed another setback thermostat and her tush gets cold on a regular basis every night, I will get the cold shoulder when it comes to sex. That alone is enough reason not to use a setback thermostat. Stretch |
#7
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prog. therm. and heat pump questions
"Stretch" wrote Many heat pump setback thermostats lock out strips during the beginning of setback recovery. On those, recovery takes a LONG time. After a number of hours, the strips are allowed back on, recovery occurs and electric bill goes up. Note that recovery without strips only works in mild weather, so setback efficiency depends on your climate. It does not work well in my climate. I have a 12 year old thermostat (Chronotherm III) that has the adaptive recovery feature as you suggested. When the system comes on (when coming out of a setback), it will try to reach the set point without bringing on the auxilary heat strips. It will only bring them on if it "looks" like it's not going to meet the set temp at the time set. Seems to work pretty well, but if it's down in the 'teens, forget it. That's when the gas logs kick in anyway.....;-] |
#8
Posted to alt.home.repair,sci.engr.heat-vent-ac,misc.consumers.frugal-living
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prog. therm. and heat pump questions
Stretch wrote
If you check the data, or measure it yourself, Strips cost 2 to 3.5 times as much per BTU as the heat pump. So you set back by shutting off the cheap heat (Heat Pump Compressor), and recover by using the expensive strip heat. Setback increases the electric bill if the heat strips come on during recovery. Nope, not with a very lossy house that loses more heat at the higher temp over the setback time than that 2/3.5 times. In addition to warming the air during recovery, you also have to warm the entire thermal mass of the house and all it's contents. Thats always been a furphy. THAT is ia big part of the added power consumption. Depends entirely on the thermal mass of the house. Here in Myrtle Beach, SC, a lot of homeowners are relocated yankees (like me), used to setback. They setback in the winter and their electric bills go up. They call me to check their system, I explain proper operation, they stop using setback in the winter and their electric bill goes back down. Happens every winter, many times. Doesnt mean that there arent situations where setback works. You dont get called out to those situations. Many heat pump setback thermostats lock out strips during the beginning of setback recovery. On those, recovery takes a LONG time. After a number of hours, the strips are allowed back on, recovery occurs and electric bill goes up. Still doesnt mean that there arent situations where setback works, particularly with deliberately oversized systems that dont need to use strips to come back off setback. Note that recovery without strips only works in mild weather, so setback efficiency depends on your climate. It does not work well in my climate. Bet it does with a bigger system. By the way, my wife, like many women, has to make several potty trips to pee every night. If I installed another setback thermostat and her tush gets cold on a regular basis every night, I will get the cold shoulder when it comes to sex. That alone is enough reason not to use a setback thermostat. The obvious approach there is a heated toilet seat, stupid. |
#9
Posted to alt.home.repair,sci.engr.heat-vent-ac,misc.consumers.frugal-living
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prog. therm. and heat pump questions
Stretch wrote:
If you check the data, or measure it yourself, Strips cost 2 to 3.5 times as much per BTU as the heat pump. That's logical, since the whole purpose of a heat pump is to be more efficient than resistive heating. So you set back by shutting off the cheap heat (Heat Pump Compressor), and recover by using the expensive strip heat. Setback increases the electric bill if the heat strips come on during recovery. In addition to warming the air during recovery, you also have to warm the entire thermal mass of the house and all it's contents. THAT is ia big part of the added power consumption. Also logical, but aren't there programmable thermostats that are smart enough to deal with this? I have a cheapo programmable thermostat which is supposed to be able to intelligently determine how much time it takes to recover. A well-designed programmable thermostat for a heat pump would be very conservative about this and would err on the side of recovering way too early (hours early) rather than having to kick in the resistive heating. I don't know that such thermostats exist, but it seems like it would not be all that hard to make one that is smart enough to avoid having to turn on the resistive heating due to setback. Machine learning techniques are pretty good these days, and the thermostat has good information available to it (the average rate the temperature drops when the system isn't running gives it an idea of the load, and the duty cycle gives it an idea of its capacity relative to the load). The worst problem seems like it would be changing weather (where it's 30F colder one night than the previous), but even that can be solved if the system realizes the temperature is dropping a lot faster over the course of the night than it was the previous night and knows not to expect last night's data to be a good indicator. - Logan |
#10
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prog. therm. and heat pump questions
Logan Shaw wrote:
Stretch wrote: If you check the data, or measure it yourself, Strips cost 2 to 3.5 times as much per BTU as the heat pump. That's logical, since the whole purpose of a heat pump is to be more efficient than resistive heating. So you set back by shutting off the cheap heat (Heat Pump Compressor), and recover by using the expensive strip heat. Setback increases the electric bill if the heat strips come on during recovery. In addition to warming the air during recovery, you also have to warm the entire thermal mass of the house and all it's contents. THAT is ia big part of the added power consumption. Also logical, but aren't there programmable thermostats that are smart enough to deal with this? I have a cheapo programmable thermostat which is supposed to be able to intelligently determine how much time it takes to recover. A well-designed programmable thermostat for a heat pump would be very conservative about this and would err on the side of recovering way too early (hours early) rather than having to kick in the resistive heating. I don't know that such thermostats exist, but it seems like it would not be all that hard to make one that is smart enough to avoid having to turn on the resistive heating due to setback. Machine learning techniques are pretty good these days, and the thermostat has good information available to it (the average rate the temperature drops when the system isn't running gives it an idea of the load, and the duty cycle gives it an idea of its capacity relative to the load). The worst problem seems like it would be changing weather (where it's 30F colder one night than the previous), but even that can be solved if the system realizes the temperature is dropping a lot faster over the course of the night than it was the previous night and knows not to expect last night's data to be a good indicator. Or just use the inside and outside temps and the measured performance of the system at that outside temp to know when it should come off the setback to have the inside temp back to normal temp at the time specified. Not a shred of rocket science required at all. |
#11
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prog. therm. and heat pump questions
Rod Speed wrote:
Logan Shaw wrote: Stretch wrote: If you check the data, or measure it yourself, Strips cost 2 to 3.5 times as much per BTU as the heat pump. That's logical, since the whole purpose of a heat pump is to be more efficient than resistive heating. So you set back by shutting off the cheap heat (Heat Pump Compressor), and recover by using the expensive strip heat. Setback increases the electric bill if the heat strips come on during recovery. In addition to warming the air during recovery, you also have to warm the entire thermal mass of the house and all it's contents. THAT is ia big part of the added power consumption. Also logical, but aren't there programmable thermostats that are smart enough to deal with this? I have a cheapo programmable thermostat which is supposed to be able to intelligently determine how much time it takes to recover. A well-designed programmable thermostat for a heat pump would be very conservative about this and would err on the side of recovering way too early (hours early) rather than having to kick in the resistive heating. I don't know that such thermostats exist, but it seems like it would not be all that hard to make one that is smart enough to avoid having to turn on the resistive heating due to setback. Machine learning techniques are pretty good these days, and the thermostat has good information available to it (the average rate the temperature drops when the system isn't running gives it an idea of the load, and the duty cycle gives it an idea of its capacity relative to the load). The worst problem seems like it would be changing weather (where it's 30F colder one night than the previous), but even that can be solved if the system realizes the temperature is dropping a lot faster over the course of the night than it was the previous night and knows not to expect last night's data to be a good indicator. Or just use the inside and outside temps and the measured performance of the system at that outside temp to know when it should come off the setback to have the inside temp back to normal temp at the time specified. Not a shred of rocket science required at all. And if the occupants of the house are going to be out for the day, is it really necessary to get back to normal temp for the short time in which they are getting up, showering etc and heading out ? It may make more sense to do that stuff at the setback temp and let the system bring the temp back up to the normal temp in the late afternoon before they are due to return instead, and be able to use the higher outside temp to get back to normal temp without using the strips at all. |
#12
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prog. therm. and heat pump questions
Rod Speed wrote: The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Wrong with the situation being discussed, with more than one system so it doesnt take a long time to get it up to the normal temp again. That is sure economically viable. To get a heat pump to work with setback, you are oversizing the system. Either a single oversized unit, or multiple units. It takes a rediculous situation to make setback work on a heat pump. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. And what was being discussed was having more than one system and doing that so it doesnt take a long time to get back to the normal temp and doesnt use the heat strips to do that. Yes multiple systems, now as high as three, just to prove a point that you can setback a heat pump. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong Yep, completely wrong. Sure, buy 3 heatpumps to prove set back. Spend extra money on the ductwork involved for three systems, including back draft dampers, lol what a crock just unsucessful in educating you. You cant even keep track of what was actually being discussed. Well I believe you were speaking first of two systems, then realized you needed three, so as not to be short cylcing in the heating mode, and in the summer having too much sensible cooling that the stat would be satisfied in 5 minutes run time. All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. Three systems sure, that is practical, So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Yep, I mentioned 3 for a reason. Plus all the ductwork and backdraft dampers. You dont have to duplicate/triplicate all of those. No you could have three systems share a common supply and return, just get it to work there einstein. Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Wasnt doing anything like that. No not at all just install three heat pumps. Or two heat pumps and a central AC. Hey maybe you could get a two stage one and a central AC. SUre is a lot of tap dancing to prove that you could viably set back a heat pump. Noah er I mean Nick is a bad influence on you. Nothing to do with Nick at all. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. Two and three was what was being discussed. Your claim that setback has no value is just plain wrong with THAT situation. Setback has a value, just not with heat pumps. A fossil fuel system sized right on the money for the heat load in a high thermal mass home may not be the best system to be setting back either. |
#13
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prog. therm. and heat pump questions
Abby Normal wrote
Rod Speed wrote The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Wrong with the situation being discussed, with more than one system so it doesnt take a long time to get it up to the normal temp again. That is sure economically viable. The economic viability wasnt being discussed. To get a heat pump to work with setback, you are oversizing the system. Either a single oversized unit, or multiple units. It takes a rediculous situation to make setback work on a heat pump. Nothing rediculous about using a surplus system to make setback work in a situation where it isnt economic to increase the insulation substantially and its quite lossy. It can be a viable approach, particularly if the normal temps are only set say in the late afternoon prior to when the house will be occupied for long when not in bed. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. And what was being discussed was having more than one system and doing that so it doesnt take a long time to get back to the normal temp and doesnt use the heat strips to do that. Yes multiple systems, now as high as three, just to prove a point that you can setback a heat pump. Its just one way to have a viable setback with a heat pump. The other obvious approach is to have the setback temp right thru till say 3pm because the occupants arent likely to need the normal temp in the hour or so when everyone is running around having showers etc before heading out of the house in the morning. Then even just a properly sized single system should be able to come back off setback quickly enough to not use the strips with a properly designed controller. Even if it starts coming off setback at say 1pm because it takes 4 hours to get back to normal temp with those outside temps, its still going go save power over no setback. And it may well be possible to design the entire system so the outside part of the system uses passive solar too if its only going to come off setback after midday. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong Yep, completely wrong. Sure, buy 3 heatpumps to prove set back. Its just ONE way to make setback viable with a heat pump. Spend extra money on the ductwork involved for three systems, including back draft dampers, You dont need all that stuff for the system thats just ensuring that you can come off setback without needing to use the strips. lol what a crock Couldnt bull**** its way out of a wet paper bag... just unsucessful in educating you. You cant even keep track of what was actually being discussed. Well I believe you were speaking first of two systems, then realized you needed three, Wrong. I JUST said that three can be useful in SOME situations. You dont even need two if you come off setback after midday, just an adequately sized system that doesnt need to use the strips on most days in winter. And if passive solar is used to help with coming back off setback after midday, thats going to make setback viable even with a heat pump. And wont necessarily cost much at all hardware wise. so as not to be short cylcing in the heating mode, and in the summer having too much sensible cooling that the stat would be satisfied in 5 minutes run time. Thats an entirely separate issue to what was being discussed, the silly pig ignorant claim that setback can never be viable with heat pumps. All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. Three systems sure, that is practical, Doesnt have to be 3, or even 2. So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Yep, I mentioned 3 for a reason. Plus all the ductwork and backdraft dampers. You dont have to duplicate/triplicate all of those. No you could have three systems share a common supply and return, just get it to work there einstein. Perfectly possible if you dont have them all running at once, gomer. Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Wasnt doing anything like that. No not at all just install three heat pumps. Or two heat pumps and a central AC. Hey maybe you could get a two stage one and a central AC. SUre is a lot of tap dancing to prove that you could viably set back a heat pump. Just one way to do setback with a heat pump. Noah er I mean Nick is a bad influence on you. Nothing to do with Nick at all. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. Two and three was what was being discussed. Your claim that setback has no value is just plain wrong with THAT situation. Setback has a value, just not with heat pumps. Wrong when stated as absolutely as that. Most obviously if the setback lasts until after midday and passive solar is used instead of the strips for coming off setback. A fossil fuel system sized right on the money for the heat load in a high thermal mass home may not be the best system to be setting back either. Having fun thrashing that straw man are you ? |
#14
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prog. therm. and heat pump questions
Rod Speed wrote: Abby Normal wrote Rod Speed wrote The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Wrong with the situation being discussed, with more than one system so it doesnt take a long time to get it up to the normal temp again. That is sure economically viable. The economic viability wasnt being discussed. No that's the problem. You want to argue the fact that you can install three heat pumps to prove that you can set one back fine, I am just pointing out to you that it is a dumb idea. To get a heat pump to work with setback, you are oversizing the system. Either a single oversized unit, or multiple units. It takes a rediculous situation to make setback work on a heat pump. Nothing rediculous about using a surplus system to make setback work in a situation where it isnt economic to increase the insulation substantially and its quite lossy. It can be a viable approach, particularly if the normal temps are only set say in the late afternoon prior to when the house will be occupied for long when not in bed. I believe i mentioned I mentioned if you were trying to set it back during the day while occupants are at work, then have it recvover while the sun is still shining. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. And what was being discussed was having more than one system and doing that so it doesnt take a long time to get back to the normal temp and doesnt use the heat strips to do that. Yes multiple systems, now as high as three, just to prove a point that you can setback a heat pump. Its just one way to have a viable setback with a heat pump. Yes I agree, if some one wants to have a viable scheme for setback then spend the money on three heating systems. Dumb idea but you have proved a point. The other obvious approach is to have the setback temp right thru till say 3pm because the occupants arent likely to need the normal temp in the hour or so when everyone is running around having showers etc before heading out of the house in the morning. Then even just a properly sized single system should be able to come back off setback quickly enough to not use the strips with a properly designed controller. Occupants gone during the day, recover before the sun sets. Even if it starts coming off setback at say 1pm because it takes 4 hours to get back to normal temp with those outside temps, its still going go save power over no setback. Without the multiple heat pump scheme, you will save energy just the slow recovery will be cool inside. Not maintaining a comfort point. So keep the home cooler save energy at the cost of comfort. Set it to 65 all the time if you want. And it may well be possible to design the entire system so the outside part of the system uses passive solar too if its only going to come off setback after midday. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong Yep, completely wrong. Sure, buy 3 heatpumps to prove set back. Its just ONE way to make setback viable with a heat pump. Well so far you have come up with tree heat pumps to prove a point. Going to extremes, rediculous. Spend extra money on the ductwork involved for three systems, including back draft dampers, You dont need all that stuff for the system thats just ensuring that you can come off setback without needing to use the strips. lol what a crock Couldnt bull**** its way out of a wet paper bag... You cannot bull **** me and say you have ever had a redundant system share common ductwork. You obviously never have. At least not with direct drive equipment typical of a residential application these days. Maybe you got lucky on some belt driven stuff. Rookie. just unsucessful in educating you. You cant even keep track of what was actually being discussed. Well I believe you were speaking first of two systems, then realized you needed three, Wrong. I JUST said that three can be useful in SOME situations. You dont even need two if you come off setback after midday, just an adequately sized system that doesnt need to use the strips on most days in winter. And if passive solar is used to help with coming back off setback after midday, thats going to make setback viable even with a heat pump. And wont necessarily cost much at all hardware wise. so as not to be short cylcing in the heating mode, and in the summer having too much sensible cooling that the stat would be satisfied in 5 minutes run time. Thats an entirely separate issue to what was being discussed, the silly pig ignorant claim that setback can never be viable with heat pumps. Well so far. without wasting power on heat strips I have seen it proposed that a system with triple the heat capacity be installed or you install three heat pumps to prove a point. Don't bring a knife to a gun fight next time. At least Nick can misapply numbers he crunches you seem to have nothing. All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. Three systems sure, that is practical, Doesnt have to be 3, or even 2. So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Yep, I mentioned 3 for a reason. Plus all the ductwork and backdraft dampers. You dont have to duplicate/triplicate all of those. No you could have three systems share a common supply and return, just get it to work there einstein. Perfectly possible if you dont have them all running at once, gomer. Like I said you obviously have never designed a working system with multiple equipment sharing common ductwork. If you had a succesful project of this nature then I suspect that some contractor saved your ass. You probaly threw up a lot of rhetoric, tried pointing fingers at everyone else but in the end the owner paid extra for your lack of experience. Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Wasnt doing anything like that. No not at all just install three heat pumps. Or two heat pumps and a central AC. Hey maybe you could get a two stage one and a central AC. SUre is a lot of tap dancing to prove that you could viably set back a heat pump. Just one way to do setback with a heat pump. Noah er I mean Nick is a bad influence on you. Nothing to do with Nick at all. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. Two and three was what was being discussed. Your claim that setback has no value is just plain wrong with THAT situation. Setback has a value, just not with heat pumps. Wrong when stated as absolutely as that. Most obviously if the setback lasts until after midday and passive solar is used instead of the strips for coming off setback. A fossil fuel system sized right on the money for the heat load in a high thermal mass home may not be the best system to be setting back either. Having fun thrashing that straw man are you ? I did not realize you were Socrates the Scarecrow. Next time I will simply light a match. |
#15
Posted to alt.home.repair,sci.engr.heat-vent-ac,misc.consumers.frugal-living
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prog. therm. and heat pump questions
Abby Normal wrote
Rod Speed wrote Abby Normal wrote Rod Speed wrote The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Wrong with the situation being discussed, with more than one system so it doesnt take a long time to get it up to the normal temp again. That is sure economically viable. The economic viability wasnt being discussed. No that's the problem. Nope. You want to argue the fact that you can install three heat pumps to prove that you can set one back fine, Lying, again. I JUST rubbed your nose in the FACT that your pig ignorant claim that setback isnt viable with heatpumps is just plain wrong. I am just pointing out to you that it is a dumb idea. No it isnt, most obviously if the extra heat pump is surplus. That can indeed make set back viable and save real money. To get a heat pump to work with setback, you are oversizing the system. Either a single oversized unit, or multiple units. It takes a rediculous situation to make setback work on a heat pump. Nothing rediculous about using a surplus system to make setback work in a situation where it isnt economic to increase the insulation substantially and its quite lossy. It can be a viable approach, particularly if the normal temps are only set say in the late afternoon prior to when the house will be occupied for long when not in bed. I believe i mentioned I mentioned if you were trying to set it back during the day while occupants are at work, then have it recvover while the sun is still shining. No you didnt. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. And what was being discussed was having more than one system and doing that so it doesnt take a long time to get back to the normal temp and doesnt use the heat strips to do that. Yes multiple systems, now as high as three, just to prove a point that you can setback a heat pump. Its just one way to have a viable setback with a heat pump. Yes I agree, if some one wants to have a viable scheme for setback then spend the money on three heating systems. That aint the only way to have a viable setback with a heat pump. Dumb idea but you have proved a point. The other obvious approach is to have the setback temp right thru till say 3pm because the occupants arent likely to need the normal temp in the hour or so when everyone is running around having showers etc before heading out of the house in the morning. Then even just a properly sized single system should be able to come back off setback quickly enough to not use the strips with a properly designed controller. Occupants gone during the day, recover before the sun sets. What I just said. Even if it starts coming off setback at say 1pm because it takes 4 hours to get back to normal temp with those outside temps, its still going go save power over no setback. Without the multiple heat pump scheme, you will save energy just the slow recovery will be cool inside. Not maintaining a comfort point. All you have to do is come off the setback well before it need to be back to comfort point. That may well be very viable if you only want the comfort point in the evening after the occupants have returned. So keep the home cooler save energy at the cost of comfort. No cost in comfort if you come off the setback with plenty of time for the slower recovery to the time you need the comfort. Set it to 65 all the time if you want. Makes a hell of a lot more sense to use a setback, and come off that well before the house needs to be back to the comfort temp, when the heat pump is working more efficiently with that return to comfort temp happening after midday etc. And it may well be possible to design the entire system so the outside part of the system uses passive solar too if its only going to come off setback after midday. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong Yep, completely wrong. Sure, buy 3 heatpumps to prove set back. Its just ONE way to make setback viable with a heat pump. Well so far you have come up with tree heat pumps to prove a point. Lying, again. It was just ONE approach to get setback viable with a heat pump. Going to extremes, rediculous. Couldnt bull**** its way out of a wet paper bag. Spend extra money on the ductwork involved for three systems, including back draft dampers, You dont need all that stuff for the system thats just ensuring that you can come off setback without needing to use the strips. lol what a crock Couldnt bull**** its way out of a wet paper bag... You cannot bull **** me and say you have ever had a redundant system share common ductwork. You obviously never have. At least not with direct drive equipment typical of a residential application these days. Maybe you got lucky on some belt driven stuff. Rookie. Couldnt bull**** its way out of a wet paper bag... just unsucessful in educating you. You cant even keep track of what was actually being discussed. Well I believe you were speaking first of two systems, then realized you needed three, Wrong. I JUST said that three can be useful in SOME situations. You dont even need two if you come off setback after midday, just an adequately sized system that doesnt need to use the strips on most days in winter. And if passive solar is used to help with coming back off setback after midday, thats going to make setback viable even with a heat pump. And wont necessarily cost much at all hardware wise. so as not to be short cylcing in the heating mode, and in the summer having too much sensible cooling that the stat would be satisfied in 5 minutes run time. Thats an entirely separate issue to what was being discussed, the silly pig ignorant claim that setback can never be viable with heat pumps. Well so far. without wasting power on heat strips I have seen it proposed that a system with triple the heat capacity be installed or you install three heat pumps to prove a point. Couldnt bull**** its way out of a wet paper bag... Don't bring a knife to a gun fight next time. At least Nick can misapply numbers he crunches you seem to have nothing. Couldnt bull**** its way out of a wet paper bag... All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. Three systems sure, that is practical, Doesnt have to be 3, or even 2. So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Yep, I mentioned 3 for a reason. Plus all the ductwork and backdraft dampers. You dont have to duplicate/triplicate all of those. No you could have three systems share a common supply and return, just get it to work there einstein. Perfectly possible if you dont have them all running at once, gomer. Like I said you obviously have never designed a working system with multiple equipment sharing common ductwork. I never said that they had to all be running at once, you pathetic excuse for a bull**** artist. If you had a succesful project of this nature then I suspect that some contractor saved your ass. You probaly threw up a lot of rhetoric, tried pointing fingers at everyone else but in the end the owner paid extra for your lack of experience. Couldnt bull**** its way out of a wet paper bag... Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Wasnt doing anything like that. No not at all just install three heat pumps. Or two heat pumps and a central AC. Hey maybe you could get a two stage one and a central AC. SUre is a lot of tap dancing to prove that you could viably set back a heat pump. Just one way to do setback with a heat pump. Noah er I mean Nick is a bad influence on you. Nothing to do with Nick at all. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. Two and three was what was being discussed. Your claim that setback has no value is just plain wrong with THAT situation. Setback has a value, just not with heat pumps. Wrong when stated as absolutely as that. Most obviously if the setback lasts until after midday and passive solar is used instead of the strips for coming off setback. A fossil fuel system sized right on the money for the heat load in a high thermal mass home may not be the best system to be setting back either. Having fun thrashing that straw man are you ? I did not realize you were Socrates the Scarecrow. Next time I will simply light a match. Couldnt bull**** its way out of a wet paper bag... |
#16
Posted to alt.home.repair,sci.engr.heat-vent-ac,misc.consumers.frugal-living
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prog. therm. and heat pump questions
Well Ron you are a smidge slower than your psuedonym suggests. You have
never had redundant systems share common duct work else you would have a clue as to what I was saying. I hired a guy from ARC Industries once, his nickname was Ronnie the Rocket. If I told him precisely what to do, he would do a good job. So far, heat pumps can be successfully set back with rediculous situations. Go back and read carefully, sound out the big words. You also have never had redundant systems share common ductwork nefore. Search 'back draft dampers' and think about forward curved direct drive fans spinning backwards. Like I said Nick will spew forth some misapplied numbers and the odd time he is on the money. Unfortunately , you do not have a clue. Rod Speed wrote: Abby Normal wrote Rod Speed wrote Abby Normal wrote Rod Speed wrote The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Wrong with the situation being discussed, with more than one system so it doesnt take a long time to get it up to the normal temp again. That is sure economically viable. The economic viability wasnt being discussed. No that's the problem. Nope. You want to argue the fact that you can install three heat pumps to prove that you can set one back fine, Lying, again. I JUST rubbed your nose in the FACT that your pig ignorant claim that setback isnt viable with heatpumps is just plain wrong. I am just pointing out to you that it is a dumb idea. No it isnt, most obviously if the extra heat pump is surplus. That can indeed make set back viable and save real money. To get a heat pump to work with setback, you are oversizing the system. Either a single oversized unit, or multiple units. It takes a rediculous situation to make setback work on a heat pump. Nothing rediculous about using a surplus system to make setback work in a situation where it isnt economic to increase the insulation substantially and its quite lossy. It can be a viable approach, particularly if the normal temps are only set say in the late afternoon prior to when the house will be occupied for long when not in bed. I believe i mentioned I mentioned if you were trying to set it back during the day while occupants are at work, then have it recvover while the sun is still shining. No you didnt. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. And what was being discussed was having more than one system and doing that so it doesnt take a long time to get back to the normal temp and doesnt use the heat strips to do that. Yes multiple systems, now as high as three, just to prove a point that you can setback a heat pump. Its just one way to have a viable setback with a heat pump. Yes I agree, if some one wants to have a viable scheme for setback then spend the money on three heating systems. That aint the only way to have a viable setback with a heat pump. Dumb idea but you have proved a point. The other obvious approach is to have the setback temp right thru till say 3pm because the occupants arent likely to need the normal temp in the hour or so when everyone is running around having showers etc before heading out of the house in the morning. Then even just a properly sized single system should be able to come back off setback quickly enough to not use the strips with a properly designed controller. Occupants gone during the day, recover before the sun sets. What I just said. Even if it starts coming off setback at say 1pm because it takes 4 hours to get back to normal temp with those outside temps, its still going go save power over no setback. Without the multiple heat pump scheme, you will save energy just the slow recovery will be cool inside. Not maintaining a comfort point. All you have to do is come off the setback well before it need to be back to comfort point. That may well be very viable if you only want the comfort point in the evening after the occupants have returned. So keep the home cooler save energy at the cost of comfort. No cost in comfort if you come off the setback with plenty of time for the slower recovery to the time you need the comfort. Set it to 65 all the time if you want. Makes a hell of a lot more sense to use a setback, and come off that well before the house needs to be back to the comfort temp, when the heat pump is working more efficiently with that return to comfort temp happening after midday etc. And it may well be possible to design the entire system so the outside part of the system uses passive solar too if its only going to come off setback after midday. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong Yep, completely wrong. Sure, buy 3 heatpumps to prove set back. Its just ONE way to make setback viable with a heat pump. Well so far you have come up with tree heat pumps to prove a point. Lying, again. It was just ONE approach to get setback viable with a heat pump. Going to extremes, rediculous. Couldnt bull**** its way out of a wet paper bag. Spend extra money on the ductwork involved for three systems, including back draft dampers, You dont need all that stuff for the system thats just ensuring that you can come off setback without needing to use the strips. lol what a crock Couldnt bull**** its way out of a wet paper bag... You cannot bull **** me and say you have ever had a redundant system share common ductwork. You obviously never have. At least not with direct drive equipment typical of a residential application these days. Maybe you got lucky on some belt driven stuff. Rookie. Couldnt bull**** its way out of a wet paper bag... just unsucessful in educating you. You cant even keep track of what was actually being discussed. Well I believe you were speaking first of two systems, then realized you needed three, Wrong. I JUST said that three can be useful in SOME situations. You dont even need two if you come off setback after midday, just an adequately sized system that doesnt need to use the strips on most days in winter. And if passive solar is used to help with coming back off setback after midday, thats going to make setback viable even with a heat pump. And wont necessarily cost much at all hardware wise. so as not to be short cylcing in the heating mode, and in the summer having too much sensible cooling that the stat would be satisfied in 5 minutes run time. Thats an entirely separate issue to what was being discussed, the silly pig ignorant claim that setback can never be viable with heat pumps. Well so far. without wasting power on heat strips I have seen it proposed that a system with triple the heat capacity be installed or you install three heat pumps to prove a point. Couldnt bull**** its way out of a wet paper bag... Don't bring a knife to a gun fight next time. At least Nick can misapply numbers he crunches you seem to have nothing. Couldnt bull**** its way out of a wet paper bag... All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. Three systems sure, that is practical, Doesnt have to be 3, or even 2. So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Yep, I mentioned 3 for a reason. Plus all the ductwork and backdraft dampers. You dont have to duplicate/triplicate all of those. No you could have three systems share a common supply and return, just get it to work there einstein. Perfectly possible if you dont have them all running at once, gomer. Like I said you obviously have never designed a working system with multiple equipment sharing common ductwork. I never said that they had to all be running at once, you pathetic excuse for a bull**** artist. If you had a succesful project of this nature then I suspect that some contractor saved your ass. You probaly threw up a lot of rhetoric, tried pointing fingers at everyone else but in the end the owner paid extra for your lack of experience. Couldnt bull**** its way out of a wet paper bag... Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Wasnt doing anything like that. No not at all just install three heat pumps. Or two heat pumps and a central AC. Hey maybe you could get a two stage one and a central AC. SUre is a lot of tap dancing to prove that you could viably set back a heat pump. Just one way to do setback with a heat pump. Noah er I mean Nick is a bad influence on you. Nothing to do with Nick at all. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. Two and three was what was being discussed. Your claim that setback has no value is just plain wrong with THAT situation. Setback has a value, just not with heat pumps. Wrong when stated as absolutely as that. Most obviously if the setback lasts until after midday and passive solar is used instead of the strips for coming off setback. A fossil fuel system sized right on the money for the heat load in a high thermal mass home may not be the best system to be setting back either. Having fun thrashing that straw man are you ? I did not realize you were Socrates the Scarecrow. Next time I will simply light a match. Couldnt bull**** its way out of a wet paper bag... |
#17
Posted to alt.home.repair,sci.engr.heat-vent-ac,misc.consumers.frugal-living
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prog. therm. and heat pump questions
Stretch wrote: Nick, If you check the data, or measure it yourself, Strips cost 2 to 3.5 times as much per BTU as the heat pump. So you set back by shutting off the cheap heat (Heat Pump Compressor), and recover by using the expensive strip heat. Setback increases the electric bill if the heat strips come on during recovery. In addition to warming the air during recovery, you also have to warm the entire thermal mass of the house and all it's contents. THAT is ia big part of the added power consumption. Here in Myrtle Beach, SC, a lot of homeowners are relocated yankees (like me), used to setback. They setback in the winter and their electric bills go up. They call me to check their system, I explain proper operation, they stop using setback in the winter and their electric bill goes back down. Happens every winter, many times. Many heat pump setback thermostats lock out strips during the beginning of setback recovery. On those, recovery takes a LONG time. After a number of hours, the strips are allowed back on, recovery occurs and electric bill goes up. Note that recovery without strips only works in mild weather, so setback efficiency depends on your climate. It does not work well in my climate. By the way, my wife, like many women, has to make several potty trips to pee every night. If I installed another setback thermostat and her tush gets cold on a regular basis every night, I will get the cold shoulder when it comes to sex. That alone is enough reason not to use a setback thermostat. Stretch The short answer seems to be that setting back will either save energy or it won't. I keep mentioning, and everyone seems to continue excluding in their calculations, the fact that even with resistance heat engaged the heat pump will also be running. The net COP during recovery will be the weighted average of the heat pump COP and 1:1, and thus greater than 1:1 when the heat pump COP is greater than 1:1. The recovery COP will depend upon the ratio of heat pump and resistance heat capacities. This is why I suggested trimming the backup resistance heat to a minimal number of elements, staging the remainder in with either t-stat programming, time delay, or return air temp. Regardless of overnight setback there will be times when the system has been set back, such as vacation, and quick recovery will be desired. During these times the remainder of the resistance heat will be called upon as needed, but will never come in during normal operation. Now here's something that nobody has yet addressed: If it is sufficiently cold in the house and outside, as in after the unit has been turned off for a long period in sub freezing weather, or perhaps was down due to some failure, then the heat pump alone may never *ever* recover at all. In fact the temperature could actually drop during the recovery attempt. Don't doubt it for an instant, as a lifelong tech I have encountered this more than once. This is a situation in which the COP of the heat pump is a misleading number. Though it may be greater than 1:1, no energy is saved over the heat strips because the house simply never warms up, and all of the runtime is effectively purely wasted energy and thus wasted dollars. The capacity is simply not enough to overcome the current level of heat loss. Thus when it is exceptionally cold in the house the heat strips will save energy during recovery. While this doesn't typically apply to normal overnight setback, it does however illustrate that the difference in COP of two heat sources doesn't equate directly to the difference in energy used and/or money saved. IOW, though the energy savings may be intact on paper, they are meaningless because you are getting nothing ot show for the money spent. During recovery without backup heat, the heat pump has to start recovery sooner, so that the added runtime of this method of recovery can indeed be greater than the cost of strip heat during recovery, infinitely greater if the heat pump's capacity has dropped so that it just equals the heat load in which case there is no recovery, period, just hours and hours of runtime with nothing to show. But even under normal circumstances we won't instantly switch to greater savings without backup heat, there is a curve involved, it's a continuum, and there must be some specific point along that curve in which the energy use is exactly the same with either method of recovery. That point depends entirely upon the system installed [it's configuration and sizing], the house in which it is installed[R values, infiltration, and thermal mass], the outdoor temp, and the indoor setback temp. There are even more variables to consider than these, but these are the major ones. You should be able to figure out from the argument above and those made in the thread by all of you, how each of these variables affect the balance, i.e. which direction of any changes in these will tip the balance in favor of backup without resistance heat or backup with resistance heat. In summary, the energy savings gained or lost depend upon very many factors and no blanket statement should even be attempted. Every system would have to be tested in the field in order to determine its energy saving potential during various ambient/indoor temp combinations, and/or off or set-back periods. IOW it's too complicated an issue for anyone here to claim to have made the correct statements about savings unless its those who said "it depends" Easiest way is to check your light bill before and after you changed your setback habits. Even if you show a savings for the one month out of two tested, this will still be meaningless unless you are sure that the month with the lower bill was as cold as or colder on average than the other and you used exactly as much additional electricity or less on other appliances, all of which contribute to the total heat load. hvacrmedic |
#18
Posted to alt.home.repair,sci.engr.heat-vent-ac,misc.consumers.frugal-living
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prog. therm. and heat pump questions
Abby Normal wrote
Well Ron you are a smidge slower than your psuedonym suggests. You have never had redundant systems share common duct work else you would have a clue as to what I was saying. Couldnt bull**** its way out of a wet paper bag... I hired a guy from ARC Industries once, his nickname was Ronnie the Rocket. If I told him precisely what to do, he would do a good job. Couldnt bull**** its way out of a wet paper bag... So far, heat pumps can be successfully set back with rediculous situations. Couldnt bull**** its way out of a wet paper bag... Most obviously when you are happy to get up in the morning and head out at the setback temp and only require the normal temp in the evening. Nothing rediculous about that approach. Go back and read carefully, sound out the big words. Couldnt bull**** its way out of a wet paper bag... You also have never had redundant systems share common ductwork nefore. Search 'back draft dampers' and think about forward curved direct drive fans spinning backwards. Couldnt bull**** its way out of a wet paper bag... Like I said Nick will spew forth some misapplied numbers and the odd time he is on the money. Unfortunately , you do not have a clue. Couldnt bull**** its way out of a wet paper bag... Rod Speed wrote: Abby Normal wrote Rod Speed wrote Abby Normal wrote Rod Speed wrote The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Wrong with the situation being discussed, with more than one system so it doesnt take a long time to get it up to the normal temp again. That is sure economically viable. The economic viability wasnt being discussed. No that's the problem. Nope. You want to argue the fact that you can install three heat pumps to prove that you can set one back fine, Lying, again. I JUST rubbed your nose in the FACT that your pig ignorant claim that setback isnt viable with heatpumps is just plain wrong. I am just pointing out to you that it is a dumb idea. No it isnt, most obviously if the extra heat pump is surplus. That can indeed make set back viable and save real money. To get a heat pump to work with setback, you are oversizing the system. Either a single oversized unit, or multiple units. It takes a rediculous situation to make setback work on a heat pump. Nothing rediculous about using a surplus system to make setback work in a situation where it isnt economic to increase the insulation substantially and its quite lossy. It can be a viable approach, particularly if the normal temps are only set say in the late afternoon prior to when the house will be occupied for long when not in bed. I believe i mentioned I mentioned if you were trying to set it back during the day while occupants are at work, then have it recvover while the sun is still shining. No you didnt. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. And what was being discussed was having more than one system and doing that so it doesnt take a long time to get back to the normal temp and doesnt use the heat strips to do that. Yes multiple systems, now as high as three, just to prove a point that you can setback a heat pump. Its just one way to have a viable setback with a heat pump. Yes I agree, if some one wants to have a viable scheme for setback then spend the money on three heating systems. That aint the only way to have a viable setback with a heat pump. Dumb idea but you have proved a point. The other obvious approach is to have the setback temp right thru till say 3pm because the occupants arent likely to need the normal temp in the hour or so when everyone is running around having showers etc before heading out of the house in the morning. Then even just a properly sized single system should be able to come back off setback quickly enough to not use the strips with a properly designed controller. Occupants gone during the day, recover before the sun sets. What I just said. Even if it starts coming off setback at say 1pm because it takes 4 hours to get back to normal temp with those outside temps, its still going go save power over no setback. Without the multiple heat pump scheme, you will save energy just the slow recovery will be cool inside. Not maintaining a comfort point. All you have to do is come off the setback well before it need to be back to comfort point. That may well be very viable if you only want the comfort point in the evening after the occupants have returned. So keep the home cooler save energy at the cost of comfort. No cost in comfort if you come off the setback with plenty of time for the slower recovery to the time you need the comfort. Set it to 65 all the time if you want. Makes a hell of a lot more sense to use a setback, and come off that well before the house needs to be back to the comfort temp, when the heat pump is working more efficiently with that return to comfort temp happening after midday etc. And it may well be possible to design the entire system so the outside part of the system uses passive solar too if its only going to come off setback after midday. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong Yep, completely wrong. Sure, buy 3 heatpumps to prove set back. Its just ONE way to make setback viable with a heat pump. Well so far you have come up with tree heat pumps to prove a point. Lying, again. It was just ONE approach to get setback viable with a heat pump. Going to extremes, rediculous. Couldnt bull**** its way out of a wet paper bag. Spend extra money on the ductwork involved for three systems, including back draft dampers, You dont need all that stuff for the system thats just ensuring that you can come off setback without needing to use the strips. lol what a crock Couldnt bull**** its way out of a wet paper bag... You cannot bull **** me and say you have ever had a redundant system share common ductwork. You obviously never have. At least not with direct drive equipment typical of a residential application these days. Maybe you got lucky on some belt driven stuff. Rookie. Couldnt bull**** its way out of a wet paper bag... just unsucessful in educating you. You cant even keep track of what was actually being discussed. Well I believe you were speaking first of two systems, then realized you needed three, Wrong. I JUST said that three can be useful in SOME situations. You dont even need two if you come off setback after midday, just an adequately sized system that doesnt need to use the strips on most days in winter. And if passive solar is used to help with coming back off setback after midday, thats going to make setback viable even with a heat pump. And wont necessarily cost much at all hardware wise. so as not to be short cylcing in the heating mode, and in the summer having too much sensible cooling that the stat would be satisfied in 5 minutes run time. Thats an entirely separate issue to what was being discussed, the silly pig ignorant claim that setback can never be viable with heat pumps. Well so far. without wasting power on heat strips I have seen it proposed that a system with triple the heat capacity be installed or you install three heat pumps to prove a point. Couldnt bull**** its way out of a wet paper bag... Don't bring a knife to a gun fight next time. At least Nick can misapply numbers he crunches you seem to have nothing. Couldnt bull**** its way out of a wet paper bag... All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. Three systems sure, that is practical, Doesnt have to be 3, or even 2. So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Yep, I mentioned 3 for a reason. Plus all the ductwork and backdraft dampers. You dont have to duplicate/triplicate all of those. No you could have three systems share a common supply and return, just get it to work there einstein. Perfectly possible if you dont have them all running at once, gomer. Like I said you obviously have never designed a working system with multiple equipment sharing common ductwork. I never said that they had to all be running at once, you pathetic excuse for a bull**** artist. If you had a succesful project of this nature then I suspect that some contractor saved your ass. You probaly threw up a lot of rhetoric, tried pointing fingers at everyone else but in the end the owner paid extra for your lack of experience. Couldnt bull**** its way out of a wet paper bag... Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Wasnt doing anything like that. No not at all just install three heat pumps. Or two heat pumps and a central AC. Hey maybe you could get a two stage one and a central AC. SUre is a lot of tap dancing to prove that you could viably set back a heat pump. Just one way to do setback with a heat pump. Noah er I mean Nick is a bad influence on you. Nothing to do with Nick at all. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. Two and three was what was being discussed. Your claim that setback has no value is just plain wrong with THAT situation. Setback has a value, just not with heat pumps. Wrong when stated as absolutely as that. Most obviously if the setback lasts until after midday and passive solar is used instead of the strips for coming off setback. A fossil fuel system sized right on the money for the heat load in a high thermal mass home may not be the best system to be setting back either. Having fun thrashing that straw man are you ? I did not realize you were Socrates the Scarecrow. Next time I will simply light a match. Couldnt bull**** its way out of a wet paper bag... |
#19
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prog. therm. and heat pump questions
Abby Normal wrote
Well Ron you are a smidge slower than your psuedonym suggests. You have never had redundant systems share common duct work else you would have a clue as to what I was saying. Couldnt bull**** its way out of a wet paper bag... Most obviously when the system used to get back off setback at a decent rate doesnt even bother with ductwork at all and is just a simple split system with no ductwork. I hired a guy from ARC Industries once, his nickname was Ronnie the Rocket. If I told him precisely what to do, he would do a good job. Couldnt bull**** its way out of a wet paper bag... So far, heat pumps can be successfully set back with rediculous situations. Couldnt bull**** its way out of a wet paper bag... Most obviously when you are happy to get up in the morning and head out at the setback temp and only require the normal temp in the evening. Nothing rediculous about that approach. Go back and read carefully, sound out the big words. Couldnt bull**** its way out of a wet paper bag... You also have never had redundant systems share common ductwork nefore. Search 'back draft dampers' and think about forward curved direct drive fans spinning backwards. Couldnt bull**** its way out of a wet paper bag... Like I said Nick will spew forth some misapplied numbers and the odd time he is on the money. Unfortunately , you do not have a clue. Couldnt bull**** its way out of a wet paper bag... Rod Speed wrote: Abby Normal wrote Rod Speed wrote Abby Normal wrote Rod Speed wrote The problem is shortly after the temperature dropped to the setback temperature, the heat pump would end up running steady just to get back up to temperature. Wrong with the situation being discussed, with more than one system so it doesnt take a long time to get it up to the normal temp again. That is sure economically viable. The economic viability wasnt being discussed. No that's the problem. Nope. You want to argue the fact that you can install three heat pumps to prove that you can set one back fine, Lying, again. I JUST rubbed your nose in the FACT that your pig ignorant claim that setback isnt viable with heatpumps is just plain wrong. I am just pointing out to you that it is a dumb idea. No it isnt, most obviously if the extra heat pump is surplus. That can indeed make set back viable and save real money. To get a heat pump to work with setback, you are oversizing the system. Either a single oversized unit, or multiple units. It takes a rediculous situation to make setback work on a heat pump. Nothing rediculous about using a surplus system to make setback work in a situation where it isnt economic to increase the insulation substantially and its quite lossy. It can be a viable approach, particularly if the normal temps are only set say in the late afternoon prior to when the house will be occupied for long when not in bed. I believe i mentioned I mentioned if you were trying to set it back during the day while occupants are at work, then have it recvover while the sun is still shining. No you didnt. Typically in the temperate states where air source heat pumps are used, they are sized with the cooling load in mind and use the heat strips. One sized for the full heat load will be grossly oversized for cooling resulting in summer time humidity control problems. And what was being discussed was having more than one system and doing that so it doesnt take a long time to get back to the normal temp and doesnt use the heat strips to do that. Yes multiple systems, now as high as three, just to prove a point that you can setback a heat pump. Its just one way to have a viable setback with a heat pump. Yes I agree, if some one wants to have a viable scheme for setback then spend the money on three heating systems. That aint the only way to have a viable setback with a heat pump. Dumb idea but you have proved a point. The other obvious approach is to have the setback temp right thru till say 3pm because the occupants arent likely to need the normal temp in the hour or so when everyone is running around having showers etc before heading out of the house in the morning. Then even just a properly sized single system should be able to come back off setback quickly enough to not use the strips with a properly designed controller. Occupants gone during the day, recover before the sun sets. What I just said. Even if it starts coming off setback at say 1pm because it takes 4 hours to get back to normal temp with those outside temps, its still going go save power over no setback. Without the multiple heat pump scheme, you will save energy just the slow recovery will be cool inside. Not maintaining a comfort point. All you have to do is come off the setback well before it need to be back to comfort point. That may well be very viable if you only want the comfort point in the evening after the occupants have returned. So keep the home cooler save energy at the cost of comfort. No cost in comfort if you come off the setback with plenty of time for the slower recovery to the time you need the comfort. Set it to 65 all the time if you want. Makes a hell of a lot more sense to use a setback, and come off that well before the house needs to be back to the comfort temp, when the heat pump is working more efficiently with that return to comfort temp happening after midday etc. And it may well be possible to design the entire system so the outside part of the system uses passive solar too if its only going to come off setback after midday. The only way set back works with a heat pump is if it is grossly oversized. Wrong again. No not wrong Yep, completely wrong. Sure, buy 3 heatpumps to prove set back. Its just ONE way to make setback viable with a heat pump. Well so far you have come up with tree heat pumps to prove a point. Lying, again. It was just ONE approach to get setback viable with a heat pump. Going to extremes, rediculous. Couldnt bull**** its way out of a wet paper bag. Spend extra money on the ductwork involved for three systems, including back draft dampers, You dont need all that stuff for the system thats just ensuring that you can come off setback without needing to use the strips. lol what a crock Couldnt bull**** its way out of a wet paper bag... You cannot bull **** me and say you have ever had a redundant system share common ductwork. You obviously never have. At least not with direct drive equipment typical of a residential application these days. Maybe you got lucky on some belt driven stuff. Rookie. Couldnt bull**** its way out of a wet paper bag... just unsucessful in educating you. You cant even keep track of what was actually being discussed. Well I believe you were speaking first of two systems, then realized you needed three, Wrong. I JUST said that three can be useful in SOME situations. You dont even need two if you come off setback after midday, just an adequately sized system that doesnt need to use the strips on most days in winter. And if passive solar is used to help with coming back off setback after midday, thats going to make setback viable even with a heat pump. And wont necessarily cost much at all hardware wise. so as not to be short cylcing in the heating mode, and in the summer having too much sensible cooling that the stat would be satisfied in 5 minutes run time. Thats an entirely separate issue to what was being discussed, the silly pig ignorant claim that setback can never be viable with heat pumps. Well so far. without wasting power on heat strips I have seen it proposed that a system with triple the heat capacity be installed or you install three heat pumps to prove a point. Couldnt bull**** its way out of a wet paper bag... Don't bring a knife to a gun fight next time. At least Nick can misapply numbers he crunches you seem to have nothing. Couldnt bull**** its way out of a wet paper bag... All that accomplishes is set back without auxiliary heat. It would short cycle inefficiently except for when it was trying to recover from a set back. Not if you one of the systems sized so that doesnt happen. Three systems sure, that is practical, Doesnt have to be 3, or even 2. So you are saying size one for the cooling load, one for the heating load and one for speedy recovery from set back then? Three heat pumps now. Yep, I mentioned 3 for a reason. Plus all the ductwork and backdraft dampers. You dont have to duplicate/triplicate all of those. No you could have three systems share a common supply and return, just get it to work there einstein. Perfectly possible if you dont have them all running at once, gomer. Like I said you obviously have never designed a working system with multiple equipment sharing common ductwork. I never said that they had to all be running at once, you pathetic excuse for a bull**** artist. If you had a succesful project of this nature then I suspect that some contractor saved your ass. You probaly threw up a lot of rhetoric, tried pointing fingers at everyone else but in the end the owner paid extra for your lack of experience. Couldnt bull**** its way out of a wet paper bag... Let's try to keep this practical and not go to hypothetical extremes to prove this is possible. Wasnt doing anything like that. No not at all just install three heat pumps. Or two heat pumps and a central AC. Hey maybe you could get a two stage one and a central AC. SUre is a lot of tap dancing to prove that you could viably set back a heat pump. Just one way to do setback with a heat pump. Noah er I mean Nick is a bad influence on you. Nothing to do with Nick at all. In an environment with an ambient dewpoint above 60F there will be problems with a grossly oversized system in cooling mode. Again, not if you have more than one system. Well like I said if you want to install three heat pumps, knock yourself out. Two and three was what was being discussed. Your claim that setback has no value is just plain wrong with THAT situation. Setback has a value, just not with heat pumps. Wrong when stated as absolutely as that. Most obviously if the setback lasts until after midday and passive solar is used instead of the strips for coming off setback. A fossil fuel system sized right on the money for the heat load in a high thermal mass home may not be the best system to be setting back either. Having fun thrashing that straw man are you ? I did not realize you were Socrates the Scarecrow. Next time I will simply light a match. Couldnt bull**** its way out of a wet paper bag... |
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prog. therm. and heat pump questions
I guess you are out of ammo, firing blanks
|
#21
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prog. therm. and heat pump questions
come back and see me when you figured out how to get multiple systems
to share common duct work rookie. |
#22
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prog. therm. and heat pump questions
Abby Normal wrote
I guess you are out of ammo, firing blanks Couldnt bull**** its way out of a wet paper bag. |
#23
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prog. therm. and heat pump questions
Abby Normal wrote
come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. Dont even need any ductwork at all with the system that is used to come off setback at a decent rate. Dont even need multiple systems either if you're happy to come off setback for the evenings and use passive solar assist to come off setback earlier in the day. Keep desperately digging, you'll be out in china any day now. |
#24
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prog. therm. and heat pump questions
Rod Speed wrote: Abby Normal wrote come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. okay so you are going to instal 3 systems now, three independent duct systems Dont even need any ductwork at all with the system that is used to come off setback at a decent rate. Okay now the system sized to provide recovery from set back is a ductless split system. Everyone sleeps with their bedroom doors open and we run the fan steady on another system to attempt to get the space temp uniform with in 5 degrees through out the house. Like I said, read carefully, sound out the big words and think before you post. Dont even need multiple systems either if you're happy to come off setback for the evenings and use passive solar assist to come off setback earlier in the day. So now you are admitting then that you need the solar gain from the sun to recover from setback. I mentioned that earlier. In another post you seem to say it is okay that it is too cold when you get up for breakfast by late afternoon the sun will make up for what your system could not do. So why set the system back in the first place, just keep it at 65F, wear the wool socks and a toque under your tin foil cap and you are comfy plus saving money. Keep desperately digging, you'll be out in china any day now. |
#25
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prog. therm. and heat pump questions
I don't know chanting the samething over and over and not thinking
before you hit 'post' or 'send' sounds like a despearte kid in Bejing already. Maybe you took a wrong turn at Albequrque. |
#26
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prog. therm. and heat pump questions
Abby Normal wrote
Rod Speed wrote Abby Normal wrote come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. okay so you are going to instal 3 systems now, Nope. three independent duct systems Nope. Dont even need any ductwork at all with the system that is used to come off setback at a decent rate. Okay now the system sized to provide recovery from set back is a ductless split system. Everyone sleeps with their bedroom doors open They dont need to when that system is JUST used to come off setback. and we run the fan steady on another system to attempt to get the space temp uniform with in 5 degrees through out the house. Even someone as stupid as you should be able to work out that if the ductless split system is JUST used to come off setback, the system which is used to maintain the normal temp will be perfectly adequate to maintain the uniform temp, just like it is if setback wasnt used. Like I said, read carefully, sound out the big words and think before you post. Like I said, couldnt bull**** its way out of a wet paper bag... Dont even need multiple systems either if you're happy to come off setback for the evenings and use passive solar assist to come off setback earlier in the day. So now you are admitting then that you need the solar gain from the sun to recover from setback. No you dont if you're happy to come off setback for the evenings. I mentioned that earlier. Lying, again. And you also pig ignorantly claimed that Setback has a value, just not with heat pumps. Cant even manage a consistent line in pig ignorant bull****. In another post you seem to say it is okay that it is too cold when you get up for breakfast by late afternoon the sun will make up for what your system could not do. Yes, some are quite happy to shower and head out at the setback temp. So why set the system back in the first place, To save on the cost of running the system, ****wit. just keep it at 65F, wear the wool socks and a toque under your tin foil cap You dont need either when its at the normal temp you require in the evening after you return. and you are comfy plus saving money. Couldnt bull**** its way out of a wet paper bag... Keep desperately digging, you'll be out in china any day now. |
#27
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prog. therm. and heat pump questions
Abby Normal wrote:
I don't know chanting the samething over and over and not thinking before you hit 'post' or 'send' sounds like a despearte kid in Bejing already. Maybe you took a wrong turn at Albequrque. Couldnt bull**** its way out of a wet paper bag... |
#28
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prog. therm. and heat pump questions
Okay rocket we are done. I am getting tired of shooting fish in a
barrel. Maybe try "are so" and "am not" next time. |
#29
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prog. therm. and heat pump questions
Wow, a troll has tried to set his hook in me. Same MO what a joke
http://groups.google.com/group/sci.p...2eba203aae58e4 |
#30
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prog. therm. and heat pump questions
Abby Normal wrote:
Wow, a troll has tried to set his hook in me. Same MO what a joke http://groups.google.com/group/sci.p...2eba203aae58e4 All he does is troll and flush toilets. |
#31
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prog. therm. and heat pump questions
Abby Normal wrote:
Okay rocket we are done. I am getting tired of shooting fish in a barrel. Maybe try "are so" and "am not" next time. Couldnt bull**** its way out of a wet paper bag. |
#32
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prog. therm. and heat pump questions
Abby Normal wrote:
Wow, a troll has tried to set his hook in me. Same MO what a joke http://groups.google.com/group/sci.p...2eba203aae58e4 Couldnt bull**** its way out of a wet paper bag. |
#33
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prog. therm. and heat pump questions
Abby Normal wrote:
Rod Speed wrote: Abby Normal wrote come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. okay so you are going to instal 3 systems now, three independent duct systems I hate to say it, but I have to concur with Rod on this one. His style of argumentation leaves a lot to be desired, but in this case, I agree with his conclusion. If you are coming off setback and using a secondary heat pump to do only that, it doesn't need duct work. If it just heats the air in one room, the primary system will be running continuously (or nearly) and will be circulating the air around the house anyway. Even if the secondary heat pump heats the air in one room up to 95F in the process, eventually that'll even out as the other system recirculates everything. And heating the air up to such a high temperature is unlikely anyway, since by definition when you are recovering from setback, the temperature is colder than you'd really like it. However, I do have to admit there could be problems if the secondary heat pump (that's used only during recovery) is putting heat mainly into the room with the thermostat. If the temperature in that room rises faster than in the rest of the house, it could cause the system to think recovery has finished when it hasn't yet gotten to that point. And if the secondary heat pump is too far away from the thermostat, it could cause the system to overshoot the target and heat up the house too much. But, those are control issues rather than duct issues, and they seem solvable. - Logan |
#34
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prog. therm. and heat pump questions
Logan Shaw wrote: Abby Normal wrote: Rod Speed wrote: Abby Normal wrote come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. okay so you are going to instal 3 systems now, three independent duct systems I hate to say it, but I have to concur with Rod on this one. His style of argumentation leaves a lot to be desired, but in this case, I agree with his conclusion. If you are coming off setback and using a secondary heat pump to do only that, it doesn't need duct work. If it just heats the air in one room, the primary system will be running continuously (or nearly) and will be circulating the air around the house anyway. Even if the secondary heat pump heats the air in one room up to 95F in the process, eventually that'll even out as the other system recirculates everything. And heating the air up to such a high temperature is unlikely anyway, since by definition when you are recovering from setback, the temperature is colder than you'd really like it. However, I do have to admit there could be problems if the secondary heat pump (that's used only during recovery) is putting heat mainly into the room with the thermostat. If the temperature in that room rises faster than in the rest of the house, it could cause the system to think recovery has finished when it hasn't yet gotten to that point. And if the secondary heat pump is too far away from the thermostat, it could cause the system to overshoot the target and heat up the house too much. But, those are control issues rather than duct issues, and they seem solvable. It isn't going to work. If you raise the temp in one room to a point higher than the desired temp, then you're going to have heat losses through the exterior walls that wouldn't have occurred with a centrally ducted system, thus defeating the purpose, at least to some extent. If you feed it into an interior room then that room will simply get too hot, no question about it. I hate to say it but it's not a very intelligent alternative. hvacrmedic |
#35
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prog. therm. and heat pump questions
Logan Shaw wrote
Abby Normal wrote Rod Speed wrote Abby Normal wrote come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. okay so you are going to instal 3 systems now, three independent duct systems I hate to say it, but I have to concur with Rod on this one. His style of argumentation leaves a lot to be desired, I only use that approach when some prat like this one attempts to bull**** its way out of its predicament with puerile **** like that one attempted. but in this case, I agree with his conclusion. If you are coming off setback and using a secondary heat pump to do only that, it doesn't need duct work. If it just heats the air in one room, the primary system will be running continuously (or nearly) and will be circulating the air around the house anyway. Even if the secondary heat pump heats the air in one room up to 95F in the process, eventually that'll even out as the other system recirculates everything. And that isnt going to happen if it heats up the main area. And heating the air up to such a high temperature is unlikely anyway, since by definition when you are recovering from setback, the temperature is colder than you'd really like it. It could happen if you were silly enough to put it in a small room. However, I do have to admit there could be problems if the secondary heat pump (that's used only during recovery) is putting heat mainly into the room with the thermostat. Nope, not if it heats the main living area. If the temperature in that room rises faster than in the rest of the house, it could cause the system to think recovery has finished when it hasn't yet gotten to that point. Not if it heats the main living area and the primary system spreads that heat out to the rest of the rooms. By definition it should have been designed to do that because it needs to do that when not coming back from the setback. And if the secondary heat pump is too far away from the thermostat, it could cause the system to overshoot the target and heat up the house too much. But, those are control issues rather than duct issues, and they seem solvable. Corse they are solvable and you dont have to use just one thermostat either. One obvious approach is to have a different one for the primary and secondary systems. |
#36
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prog. therm. and heat pump questions
RP wrote:
Logan Shaw wrote: Abby Normal wrote: Rod Speed wrote: Abby Normal wrote come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. okay so you are going to instal 3 systems now, three independent duct systems I hate to say it, but I have to concur with Rod on this one. His style of argumentation leaves a lot to be desired, but in this case, I agree with his conclusion. If you are coming off setback and using a secondary heat pump to do only that, it doesn't need duct work. If it just heats the air in one room, the primary system will be running continuously (or nearly) and will be circulating the air around the house anyway. Even if the secondary heat pump heats the air in one room up to 95F in the process, eventually that'll even out as the other system recirculates everything. And heating the air up to such a high temperature is unlikely anyway, since by definition when you are recovering from setback, the temperature is colder than you'd really like it. However, I do have to admit there could be problems if the secondary heat pump (that's used only during recovery) is putting heat mainly into the room with the thermostat. If the temperature in that room rises faster than in the rest of the house, it could cause the system to think recovery has finished when it hasn't yet gotten to that point. And if the secondary heat pump is too far away from the thermostat, it could cause the system to overshoot the target and heat up the house too much. But, those are control issues rather than duct issues, and they seem solvable. It isn't going to work. Corse it'll work. If you raise the temp in one room to a point higher than the desired temp, That isnt going to happen when the secondary system is JUST used to come off the setback in a reasonable time. then you're going to have heat losses through the exterior walls that wouldn't have occurred with a centrally ducted system, thus defeating the purpose, at least to some extent. Nope. If you feed it into an interior room then that room will simply get too hot, no question about it. Wrong again. I hate to say it but it's not a very intelligent alternative. Corse it will work fine. No reason why the secondary system cant have a slightly lower than normal temperature set so it recovers from the setback in a decent time and then stops and leaves the primary system to get the temp back up to normal. Thats going to happen fine since the temp difference is well within its capabilitys. |
#37
Posted to alt.home.repair,sci.engr.heat-vent-ac,misc.consumers.frugal-living
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prog. therm. and heat pump questions
Rod Speed wrote: RP wrote: Logan Shaw wrote: Abby Normal wrote: Rod Speed wrote: Abby Normal wrote come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. okay so you are going to instal 3 systems now, three independent duct systems I hate to say it, but I have to concur with Rod on this one. His style of argumentation leaves a lot to be desired, but in this case, I agree with his conclusion. If you are coming off setback and using a secondary heat pump to do only that, it doesn't need duct work. If it just heats the air in one room, the primary system will be running continuously (or nearly) and will be circulating the air around the house anyway. Even if the secondary heat pump heats the air in one room up to 95F in the process, eventually that'll even out as the other system recirculates everything. And heating the air up to such a high temperature is unlikely anyway, since by definition when you are recovering from setback, the temperature is colder than you'd really like it. However, I do have to admit there could be problems if the secondary heat pump (that's used only during recovery) is putting heat mainly into the room with the thermostat. If the temperature in that room rises faster than in the rest of the house, it could cause the system to think recovery has finished when it hasn't yet gotten to that point. And if the secondary heat pump is too far away from the thermostat, it could cause the system to overshoot the target and heat up the house too much. But, those are control issues rather than duct issues, and they seem solvable. It isn't going to work. Corse it'll work. If you raise the temp in one room to a point higher than the desired temp, That isnt going to happen when the secondary system is JUST used to come off the setback in a reasonable time. then you're going to have heat losses through the exterior walls that wouldn't have occurred with a centrally ducted system, thus defeating the purpose, at least to some extent. Nope. If you feed it into an interior room then that room will simply get too hot, no question about it. Wrong again. I hate to say it but it's not a very intelligent alternative. Corse it will work fine. No reason why the secondary system cant have a slightly lower than normal temperature set so it recovers from the setback in a decent time and then stops and leaves the primary system to get the temp back up to normal. Thats going to happen fine since the temp difference is well within its capabilitys. Supposing that I grant your every point, what would be the point of such a system? Wouldn't it be much easier to simply install a larger staged system? hvacrmedic |
#38
Posted to alt.home.repair,sci.engr.heat-vent-ac,misc.consumers.frugal-living
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prog. therm. and heat pump questions
RP wrote:
Rod Speed wrote: RP wrote: Logan Shaw wrote: Abby Normal wrote: Rod Speed wrote: Abby Normal wrote come back and see me when you figured out how to get multiple systems to share common duct work rookie. Dont have to share the same ductwork, ****wit. okay so you are going to instal 3 systems now, three independent duct systems I hate to say it, but I have to concur with Rod on this one. His style of argumentation leaves a lot to be desired, but in this case, I agree with his conclusion. If you are coming off setback and using a secondary heat pump to do only that, it doesn't need duct work. If it just heats the air in one room, the primary system will be running continuously (or nearly) and will be circulating the air around the house anyway. Even if the secondary heat pump heats the air in one room up to 95F in the process, eventually that'll even out as the other system recirculates everything. And heating the air up to such a high temperature is unlikely anyway, since by definition when you are recovering from setback, the temperature is colder than you'd really like it. However, I do have to admit there could be problems if the secondary heat pump (that's used only during recovery) is putting heat mainly into the room with the thermostat. If the temperature in that room rises faster than in the rest of the house, it could cause the system to think recovery has finished when it hasn't yet gotten to that point. And if the secondary heat pump is too far away from the thermostat, it could cause the system to overshoot the target and heat up the house too much. But, those are control issues rather than duct issues, and they seem solvable. It isn't going to work. Corse it'll work. If you raise the temp in one room to a point higher than the desired temp, That isnt going to happen when the secondary system is JUST used to come off the setback in a reasonable time. then you're going to have heat losses through the exterior walls that wouldn't have occurred with a centrally ducted system, thus defeating the purpose, at least to some extent. Nope. If you feed it into an interior room then that room will simply get too hot, no question about it. Wrong again. I hate to say it but it's not a very intelligent alternative. Corse it will work fine. No reason why the secondary system cant have a slightly lower than normal temperature set so it recovers from the setback in a decent time and then stops and leaves the primary system to get the temp back up to normal. Thats going to happen fine since the temp difference is well within its capabilitys. Supposing that I grant your every point, what would be the point of such a system? It makes setback viable with a heat pump. Wouldn't it be much easier to simply install a larger staged system? Nope, and likely quite a bit cheaper not to too. If there was not going to be anyone in the house during the day, I'd personally run the setback right thru to the afternoon and have the system come back off setpoint at a time that would ensure that it was back to normal temp by the time everyone came home again and thru the evening. Go back onto setback after everyone has gone to bed. |
#39
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prog. therm. and heat pump questions
Maybe the scheme could get more elaborate yet to prove the setback
scheme. Put a small ductless split heat pump in each room. |
#40
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prog. therm. and heat pump questions
On 19 Dec 2005 11:26:21 -0800, "Abby Normal"
wrote: Maybe the scheme could get more elaborate yet to prove the setback scheme. I just got off the blower with a creditor, and I don't want to hear any setback scheme crap right now! :-) Put a small ductless split heat pump in each room. The ultimate zone system. :-) -- -john wide-open at throttle dot info ~~~~~~~~ The time to repair the roof is when the sun is shining - JFK ~~~~~~~~ |
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