Rod Speed wrote:
Abby Normal wrote
Rod Speed wrote
In effect the ductless split system is just like the strips except
that its much more efficient than the strips for when the primary
system doesnt have enough horsepower to come back off setback
quickly enough
Actually with the heat strips in an auxilairy heat function, the heat
strips are in series with the heat pump indoor air coil and the supply
air temperature distributed through out the space is elevated above
what the heat pump can put out. An electrical analogy would be two
heat sources in series.
Irrelevant to it being a more expensive source of that heat.
Well you said the ductless split is just like the strips
except...........
So I merely pointed out the fundamental difference you were not aware
of.
The ductless booster system will heat up a common area
that would also be recieving heat from the central ducted
system. Now you have two heat sources in parallel so it
already is a smidge different than using the heat strips.
Irrelevant to strips being a more expensive source of that heat.
Just the fundamental difference. The heat strips get the job done but
you have not really thought out this parallel heat scheme of yours in
the central area. You get a little bit of the series action as you try
to trickle heat into the rooms.
So to avoid the room getting overly hot
the ductless system would shut off.
ONLY when its got the common area back off setback.
That is what I said. The booster is in the central area, it heats the
central area in addition to the primary system. Therefore it and the
primary system warms up the central area so the booster shuts off and
the primary system shuts off or the central area is overheated. So you
can think about your multiple thermostats and where exactly you are
going to put the primary stat. Maybe even motorized dampers on the
primary supply to the central area. So you shut off the supplies to the
central area so not to overheat but you need to draw return from the
central area to try and get this extra heat to the rooms. Hmm this
depressurizes central area, causes infiltration, increases heat load.
Don't see you getting out of overheating the central area rocket. Give
up now on the ductless booster its a dog.
A big problem is to get heat to the other areas, you will most likely
find that you need to overheat the central area. Others have pointed
out how this wastes energy. I pointed out how it also reduces the
efficiency of the booster in addition to wasting heat.
Thats what you want it to do.
You have warmed up the central area but
all the other rooms are still not recovered.
Wrong, the primary system will be circulating that
warmed up air from the central area to the other areas.
Probably the primary system moves air based on the fact that perhaps it
supplies air maybe 20 degrees F warmer than the room air, and this is
to maintain temperature not recover the temperature. Maybe it gets up
to a little higher differential in your easy climate and relatively
warm winter ambient maybe you are getting 25 to 30 F degree rise. Okay
lets call it a 25 degree rise.
See you are a little vague, and won't layout exactly what you are
proposing, probably worried as it makes you feel vulnerable but here is
a stab at a scenario.
If the primary system was in heat mode, and in your case the summers
are so dry you never have to worry about dehumidification , then the
primary system could be sized for the design heat load.
An elevated return temperature from the common area is not really going
to do much here, maybe cause the air into the primary heat pump to be 2
degrees F or so warmer than straight return from all the set back
rooms. A slight increase in return temperature will also lower the heat
output of the primary heat pump and cause a slight drop in COP.
So if you neglect the drop in heat output/COP of the primary system
here is some quick numbers for some easy math that also ignores thermal
mass.
If the primary system was doing a 25 degree F rise, the central booster
without overheating the central area gives a net heat increase to the
supply air temp of the primary system of perhaps (2F) 8% as a best
case.
So maybe the ambient is 45F, set point is 70F and the set back temp is
65F.
Design differential 70-45=35F, trying to recover 5/35x100=14% and
recovery scheme increases heat output by 8%. Think you will be waiting
for the sun to start shining or you are going to be really elevating
the temperature of the central area to be able to recover.
So with a primary system sized for 100% of the design load and with a
ductless central booster you have a slim chance of being able to
recover and this is far from a viable scheme. So far most of the
savings of this booster heat pump are eroding away.
Maybe overheat that central area and have a bunch of through the wall
fans to draw heated central core air into the rooms then transfer back
through door grilles, under cut doors. Just keeps getting more
rediculous.
I'll tell you what rocket, you summarize a scheme that pays for itself
in 20 years over heat strips and I will concede you can set back a heat
pump in OZ. Good luck when the climate is so humid it needs DX cooling
tho.
Or forget the setback, just keep the same low setpoint, and have a
treat in the afternoon when the sun warms up the house to 70F. Without
the strips you are going to be challenged to recover. You recover for
comfort and if you are not going to be comfortable except for late
afternoon why bother in the first place.
Hey maybe summarize it is 68F being set back to 66F, it will recover
but the set back savings dry up.
I think your central booster scheme is a dog, but please feel free to
work it all out and summarize it. Maybe you can finally give me that
nose rubbing.
So you could keep the all the bedroom doors open to allow them
to gain as much heat as they could from the booster heater in the
living room, but you will not have anything close to uniform heat.
Thanks for that completely superfluous proof that you
have never ever had a ****ing clue about the basics.
AND when people have got up, it doesnt matter if the
bedrooms arent YET back to the normal temp anyway.
Either the bedroom occupant is still in the bed, and has
been at the setback temp up till then, or they have got
up and have moved to the central areas, stupid.
Well you gave up on the morning setback, so now just have the central
area warm and all is well. How about some auxiliary radiant floor heat
in the loo. Or is it truly a throne there in Oz, you all take a crap in
the middle of your living room?
Like a superinsulated home with a central
fireplace burning kangaroo chips.
Thanks for that completely superfluous proof that you
have never ever had a ****ing clue about the basics.
Actually that will be analogous to what it is like when you find out
you have to heat the central area up to 80 degrees F to get your
recovery scheme to work.
Reams of your pathetic attempts at a troll flushed where it belongs.
Hey I must be good at this troll stuff, I got you to actually say
something beyond blotto and wet paper bags.