We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

--
Maggie

On Friday, October 9, 2015 at 12:26:10 PM UTC-4, Muggles wrote:
We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and

plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

--
Maggie

From the description, very unclear what the objectives and requirements
really are.

"We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.


If you're heating the GH, how will the temps drop dramatically? Fish?
Where are the fish, in the GH? In the tanks? In the tanks that are
in the GH?

Heat tape isn't going to do much at all to raise the temp of water
running through it. It's designed to keep the temp of water in the
pipes above freezing when the water isn't moving. You'd have to have
a very long pipe and/or very little water flow for heat tape to make
a significant temp rise in the water. But you also say that you need
to keep the water in the tanks warm? Without knowing how much water
is required, what kind of temp rise, etc, not much to go on.

On 10/9/2015 11:35 AM, trader_4 wrote:
On Friday, October 9, 2015 at 12:26:10 PM UTC-4, Muggles wrote:
We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and

plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

--
Maggie

From the description, very unclear what the objectives and requirements
really are.

"We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.


If you're heating the GH, how will the temps drop dramatically? Fish?
Where are the fish, in the GH? In the tanks? In the tanks that are
in the GH?

During the day the sun can raise the temps in a green house quite a lot,
but at night all the heat is lost from the air and it pulls the heat
from the water too. It was a big issue with our hoop house. We heated
it with tank heaters plus propane heaters.

Heat tape isn't going to do much at all to raise the temp of water
running through it. It's designed to keep the temp of water in the
pipes above freezing when the water isn't moving. You'd have to have
a very long pipe and/or very little water flow for heat tape to make
a significant temp rise in the water. But you also say that you need
to keep the water in the tanks warm? Without knowing how much water
is required, what kind of temp rise, etc, not much to go on.


I think the low temp the fish can tolerate is in the middle 60's, but
that's pushing it. The plants can tolerate some change at night in the
temps, but if the temps go too low they start to lose leaves and
production is set back.

--
Maggie

On Friday, October 9, 2015 at 12:43:43 PM UTC-4, Muggles wrote:
On 10/9/2015 11:35 AM, trader_4 wrote:
On Friday, October 9, 2015 at 12:26:10 PM UTC-4, Muggles wrote:
We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and

plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

--
Maggie

From the description, very unclear what the objectives and requirements
really are.

"We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.


If you're heating the GH, how will the temps drop dramatically? Fish?
Where are the fish, in the GH? In the tanks? In the tanks that are
in the GH?

During the day the sun can raise the temps in a green house quite a lot,
but at night all the heat is lost from the air and it pulls the heat
from the water too. It was a big issue with our hoop house. We heated
it with tank heaters plus propane heaters.

Heat tape isn't going to do much at all to raise the temp of water
running through it. It's designed to keep the temp of water in the
pipes above freezing when the water isn't moving. You'd have to have
a very long pipe and/or very little water flow for heat tape to make
a significant temp rise in the water. But you also say that you need
to keep the water in the tanks warm? Without knowing how much water
is required, what kind of temp rise, etc, not much to go on.


I think the low temp the fish can tolerate is in the middle 60's, but
that's pushing it. The plants can tolerate some change at night in the
temps, but if the temps go too low they start to lose leaves and
production is set back.

--
Maggie

Wow, that sure added a lot of clarity. I have a car, it won't go.
What's wrong with it?

On Fri, 9 Oct 2015 09:35:17 -0700 (PDT), trader_4
wrote:

From the description, very unclear what the objectives and requirements
really are.

Maybe this is what she is trying to do?

https://www.youtube.com/watch?v=9qZPwBPAqks

She could contact: (for heating solutions)...I guess

www.growingpower.org

www.seagrant.wisc.edu

On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

It's pretty simple thermodynamics.
In summary, "there ain't no free lunch"
A lot depends on the geometry of your system
and how the heat gets in and out.
You insulate the system.
You replace the energy that's lost. Costs the same, given
the same energy source, no matter how you do it.

The water tank has very much more volume than the pipe.
You have to either raise the pipe temperature considerably,
or move a lot of water thru it.

PVC pipe is a lousy conductor. Use metal pipe if you
insist on heat tape.
Use multiple temperature sensors so a single point failure
won't kill your fish.
There are several types of heat tape. The self regulating
ones won't help you. You need unregulated tape that can
withstand the temperatures you need and some kind of controller.

I bought one of these and built it into a wall electrical box.
I plan to use it this winter to control heat tape on the outside
water spigot.
http://www.buyincoins.com/item/45040.html

What if you put a small domestic water heater in the water loop?
Put light bulbs in series with the heating element.
The water heater heats the water. Lights heat the air in
a manner that's easy to distribute to get heat right where you need it.
Size the lights so that the ratio of heat in water/air is
right for your application. Put the temperature controller
on that.

On 10/9/2015 10:25 AM, mike wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

It's pretty simple thermodynamics.
In summary, "there ain't no free lunch"
A lot depends on the geometry of your system
and how the heat gets in and out.
You insulate the system.
You replace the energy that's lost. Costs the same, given
the same energy source, no matter how you do it.

The water tank has very much more volume than the pipe.
You have to either raise the pipe temperature considerably,
or move a lot of water thru it.

PVC pipe is a lousy conductor. Use metal pipe if you
insist on heat tape.
Use multiple temperature sensors so a single point failure
won't kill your fish.
There are several types of heat tape. The self regulating
ones won't help you. You need unregulated tape that can
withstand the temperatures you need and some kind of controller.

I bought one of these and built it into a wall electrical box.
I plan to use it this winter to control heat tape on the outside
water spigot.
http://www.buyincoins.com/item/45040.html
This one is better packaged for your application.
http://www.buyincoins.com/item/15054.html

What if you put a small domestic water heater in the water loop?
Put light bulbs in series with the heating element.
The water heater heats the water. Lights heat the air in
a manner that's easy to distribute to get heat right where you need it.
Size the lights so that the ratio of heat in water/air is
right for your application. Put the temperature controller
on that.

On Friday, October 9, 2015 at 12:28:37 PM UTC-5, mike wrote:
On 10/9/2015 10:25 AM, mike wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

It's pretty simple thermodynamics.
In summary, "there ain't no free lunch"
A lot depends on the geometry of your system
and how the heat gets in and out.
You insulate the system.
You replace the energy that's lost. Costs the same, given
the same energy source, no matter how you do it.

The water tank has very much more volume than the pipe.
You have to either raise the pipe temperature considerably,
or move a lot of water thru it.

PVC pipe is a lousy conductor. Use metal pipe if you
insist on heat tape.
Use multiple temperature sensors so a single point failure
won't kill your fish.
There are several types of heat tape. The self regulating
ones won't help you. You need unregulated tape that can
withstand the temperatures you need and some kind of controller.

I bought one of these and built it into a wall electrical box.
I plan to use it this winter to control heat tape on the outside
water spigot.
http://www.buyincoins.com/item/45040.html
This one is better packaged for your application.
http://www.buyincoins.com/item/15054.html

What if you put a small domestic water heater in the water loop?
Put light bulbs in series with the heating element.
The water heater heats the water. Lights heat the air in
a manner that's easy to distribute to get heat right where you need it.
Size the lights so that the ratio of heat in water/air is
right for your application. Put the temperature controller
on that.


I like the prices! Thanks for posting the link. ^_^

[8~{} Uncle Cheap Monster

On Friday, October 9, 2015 at 1:26:17 PM UTC-4, mike wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

It's pretty simple thermodynamics.
In summary, "there ain't no free lunch"
A lot depends on the geometry of your system
and how the heat gets in and out.
You insulate the system.
You replace the energy that's lost. Costs the same, given
the same energy source, no matter how you do it.

The water tank has very much more volume than the pipe.
You have to either raise the pipe temperature considerably,
or move a lot of water thru it.

PVC pipe is a lousy conductor. Use metal pipe if you
insist on heat tape.
Use multiple temperature sensors so a single point failure
won't kill your fish.
There are several types of heat tape. The self regulating
ones won't help you. You need unregulated tape that can
withstand the temperatures you need and some kind of controller.

I bought one of these and built it into a wall electrical box.
I plan to use it this winter to control heat tape on the outside
water spigot.
http://www.buyincoins.com/item/45040.html

What if you put a small domestic water heater in the water loop?
Put light bulbs in series with the heating element.
The water heater heats the water. Lights heat the air in
a manner that's easy to distribute to get heat right where you need it.

Size the lights so that the ratio of heat in water/air is
right for your application. Put the temperature controller
on that.

And there goes any remaining hope of sanity..... Did someone put
something in the water today?

On 10/9/2015 12:25 PM, mike wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?


It's pretty simple thermodynamics.
In summary, "there ain't no free lunch"
A lot depends on the geometry of your system
and how the heat gets in and out.
You insulate the system.
You replace the energy that's lost. Costs the same, given
the same energy source, no matter how you do it.

The water tank has very much more volume than the pipe.
You have to either raise the pipe temperature considerably,
or move a lot of water thru it.

We've been experimenting with various options. One thing we've done is
turn off the water circulation during the colder evening hours and the
sheer volume/mass of the water loses very little warmth at night. That
might be another option. We already have timers on the pumps.

PVC pipe is a lousy conductor. Use metal pipe if you
insist on heat tape.
Use multiple temperature sensors so a single point failure
won't kill your fish.
There are several types of heat tape. The self regulating
ones won't help you. You need unregulated tape that can
withstand the temperatures you need and some kind of controller.

I wasn't even sure if heat tape would be an option to try. It's not
looking like it would work based on what people are saying so far.

I bought one of these and built it into a wall electrical box.
I plan to use it this winter to control heat tape on the outside
water spigot.
http://www.buyincoins.com/item/45040.html

What if you put a small domestic water heater in the water loop?
Put light bulbs in series with the heating element.
The water heater heats the water. Lights heat the air in
a manner that's easy to distribute to get heat right where you need it.
Size the lights so that the ratio of heat in water/air is
right for your application. Put the temperature controller
on that.


hmm hadn't thought of a small water heater. Interesting.

We are building a rocket stove and have already buried pipe in the
ground for that. It seems many people incorporate those in their green
house designs.

--
Maggie

Muggles wrote:
On 10/9/2015 12:25 PM, mike wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water
into grow beds so the plants and plant media can filter the water,
pump that water into a sump and then that water goes to a large
rock and sand filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green
house itself. We're going to have about 800 to 1000 gallons of
water in the green house tanks, plus have passive solar heat from
the ground that'll have a thick layer of gravel in addition to
having windows at the proper angle to capture the winter sunlight
and heat. We'll also have vents and windows we can open at the peak
of the green house to vent moisture and too much hot air when
needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at
night, so I was thinking of using heat cables/tapes around the pvc
pipes that connect all the water flowing from tanks to plants to
sump to filter vs. using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at
the same time keep the temps more stable in the green house. All
the walls and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?


It's pretty simple thermodynamics.
In summary, "there ain't no free lunch"
A lot depends on the geometry of your system
and how the heat gets in and out.
You insulate the system.
You replace the energy that's lost. Costs the same, given
the same energy source, no matter how you do it.

The water tank has very much more volume than the pipe.
You have to either raise the pipe temperature considerably,
or move a lot of water thru it.

We've been experimenting with various options. One thing we've done
is turn off the water circulation during the colder evening hours and
the sheer volume/mass of the water loses very little warmth at night.
That might be another option. We already have timers on the pumps.

PVC pipe is a lousy conductor. Use metal pipe if you
insist on heat tape.
Use multiple temperature sensors so a single point failure
won't kill your fish.
There are several types of heat tape. The self regulating
ones won't help you. You need unregulated tape that can
withstand the temperatures you need and some kind of controller.

I wasn't even sure if heat tape would be an option to try. It's not
looking like it would work based on what people are saying so far.

I bought one of these and built it into a wall electrical box.
I plan to use it this winter to control heat tape on the outside
water spigot.
http://www.buyincoins.com/item/45040.html

What if you put a small domestic water heater in the water loop?
Put light bulbs in series with the heating element.
The water heater heats the water. Lights heat the air in
a manner that's easy to distribute to get heat right where you need
it. Size the lights so that the ratio of heat in water/air is
right for your application. Put the temperature controller
on that.


hmm hadn't thought of a small water heater. Interesting.

We are building a rocket stove and have already buried pipe in the
ground for that. It seems many people incorporate those in their
green house designs.

On a circulating water system, you could easily use an in-line water heater,
like a spa heater, or even just a water heater element installed into a "T" in
a section of pipe that the water flows through. You probably want to find a
stainless coated heater element rather than the normal copper ones for the
somewhat corrosive water you're dealing with. You'd have to make sure the heat
only goes on while water is flowing. Such heater are a common homebrew spa
heater.

An electric water heater could be used now, and serve as a backup to the wood
stove later.


The heat tape solution is a very indirect way to keep the water warm.

On 10/10/2015 2:23 PM, Bob F wrote:
Muggles wrote:
On 10/9/2015 12:25 PM, mike wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water
into grow beds so the plants and plant media can filter the water,
pump that water into a sump and then that water goes to a large
rock and sand filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green
house itself. We're going to have about 800 to 1000 gallons of
water in the green house tanks, plus have passive solar heat from
the ground that'll have a thick layer of gravel in addition to
having windows at the proper angle to capture the winter sunlight
and heat. We'll also have vents and windows we can open at the peak
of the green house to vent moisture and too much hot air when
needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at
night, so I was thinking of using heat cables/tapes around the pvc
pipes that connect all the water flowing from tanks to plants to
sump to filter vs. using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at
the same time keep the temps more stable in the green house. All
the walls and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?


It's pretty simple thermodynamics.
In summary, "there ain't no free lunch"
A lot depends on the geometry of your system
and how the heat gets in and out.
You insulate the system.
You replace the energy that's lost. Costs the same, given
the same energy source, no matter how you do it.

The water tank has very much more volume than the pipe.
You have to either raise the pipe temperature considerably,
or move a lot of water thru it.

We've been experimenting with various options. One thing we've done
is turn off the water circulation during the colder evening hours and
the sheer volume/mass of the water loses very little warmth at night.
That might be another option. We already have timers on the pumps.

PVC pipe is a lousy conductor. Use metal pipe if you
insist on heat tape.
Use multiple temperature sensors so a single point failure
won't kill your fish.
There are several types of heat tape. The self regulating
ones won't help you. You need unregulated tape that can
withstand the temperatures you need and some kind of controller.

I wasn't even sure if heat tape would be an option to try. It's not
looking like it would work based on what people are saying so far.

I bought one of these and built it into a wall electrical box.
I plan to use it this winter to control heat tape on the outside
water spigot.
http://www.buyincoins.com/item/45040.html

What if you put a small domestic water heater in the water loop?
Put light bulbs in series with the heating element.
The water heater heats the water. Lights heat the air in
a manner that's easy to distribute to get heat right where you need
it. Size the lights so that the ratio of heat in water/air is
right for your application. Put the temperature controller
on that.


hmm hadn't thought of a small water heater. Interesting.

We are building a rocket stove and have already buried pipe in the
ground for that. It seems many people incorporate those in their
green house designs.

On a circulating water system, you could easily use an in-line water heater,
like a spa heater, or even just a water heater element installed into a "T" in
a section of pipe that the water flows through. You probably want to find a
stainless coated heater element rather than the normal copper ones for the
somewhat corrosive water you're dealing with. You'd have to make sure the heat
only goes on while water is flowing. Such heater are a common homebrew spa
heater.

An electric water heater could be used now, and serve as a backup to the wood
stove later.


The heat tape solution is a very indirect way to keep the water warm.



OK ... I'll check into that option. thanks!

--
Maggie

On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

What is the year-round soil temperature in your area?
E.g., often there is very little seasonal fluctuation in that
temperature once you are below frost line.

You may find it more economical to "sink" the tanks to that level
to take advantage of the thermal mass of the soil to maintain a
nominal temperature. Likewise for the plumbing.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

What's the relative cost of water in your area? E.g., here, prior to
predicted low temperatures. we water the citrus trees heavily.
This helps hydrate the tress but also helps the soil under the
trees hold heat and radiate it upward as the air temperatures
fall. (but, we are typically looking for very small gains -- just
to keep the trees from damage as they approach their limit of ~28F)

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

You can also explore a "poor man's" ground-sourced heat pump system.
I.e., you aren't concerned with bringing that heat into a living space.
So, a below grade pipe (even channels of cinderblocks?) with air
blown through could bring the temperature in the greenhouse up a bit
(from what would otherwise be ambient). A water-based approach would
be more efficient but also more costly.

Does anyone know if heating tapes would work for this or not?

On 10/9/2015 12:50 PM, Don Y wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

What is the year-round soil temperature in your area?
E.g., often there is very little seasonal fluctuation in that
temperature once you are below frost line.

You may find it more economical to "sink" the tanks to that level
to take advantage of the thermal mass of the soil to maintain a
nominal temperature. Likewise for the plumbing.

We can't really sink these tanks into the ground because they are pretty
big and they need to be mobile (in case we need to disassemble the green
house at some point). We are building a rocket stove, though, and it
has venting buried for that.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.


What's the relative cost of water in your area? E.g., here, prior to
predicted low temperatures. we water the citrus trees heavily.
This helps hydrate the tress but also helps the soil under the
trees hold heat and radiate it upward as the air temperatures
fall. (but, we are typically looking for very small gains -- just
to keep the trees from damage as they approach their limit of ~28F)

We don't really see much in the way of a water cost increase because the
tanks are filled and the water is re-circulated continuously. Every
couple of weeks we will add water to the main tank, but it's really not
much to maintain water levels. The grow beds are directly above the
water tanks right now, but we may move them and alter the current design
of the water flow once the new green house is ready to move everything
into it (maybe in another couple of weeks).

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

You can also explore a "poor man's" ground-sourced heat pump system.
I.e., you aren't concerned with bringing that heat into a living space.
So, a below grade pipe (even channels of cinderblocks?) with air
blown through could bring the temperature in the greenhouse up a bit
(from what would otherwise be ambient). A water-based approach would
be more efficient but also more costly.

Right now we're planning for several passive heat sources: the water
itself will hold heat, the floor is gravel, and a rocket stove. For
additional heat we use portable propane heaters.



--
Maggie

On 10/9/2015 1:40 PM, Muggles wrote:
On 10/9/2015 12:50 PM, Don Y wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

What is the year-round soil temperature in your area?
E.g., often there is very little seasonal fluctuation in that
temperature once you are below frost line.

You may find it more economical to "sink" the tanks to that level
to take advantage of the thermal mass of the soil to maintain a
nominal temperature. Likewise for the plumbing.

We can't really sink these tanks into the ground because they are pretty
big and they need to be mobile (in case we need to disassemble the green
house at some point). We are building a rocket stove, though, and it
has venting buried for that.

Can you berm earth around them (or water tanks, etc.)? Anything to add to
the thermal mass that *insulates* them from the surrounding air temperatures?

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.


What's the relative cost of water in your area? E.g., here, prior to
predicted low temperatures. we water the citrus trees heavily.
This helps hydrate the tress but also helps the soil under the
trees hold heat and radiate it upward as the air temperatures
fall. (but, we are typically looking for very small gains -- just
to keep the trees from damage as they approach their limit of ~28F)

We don't really see much in the way of a water cost increase because the
tanks are filled and the water is re-circulated continuously. Every
couple of weeks we will add water to the main tank, but it's really not
much to maintain water levels. The grow beds are directly above the
water tanks right now, but we may move them and alter the current design
of the water flow once the new green house is ready to move everything
into it (maybe in another couple of weeks).

My point was whether you could afford to "throw away" water by hydrating
the soil in the area to add to the effective thermal mass *in*
the greenhouse. Water is easy to "move"; blocks of stone, not so easy!

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

You can also explore a "poor man's" ground-sourced heat pump system.
I.e., you aren't concerned with bringing that heat into a living space.
So, a below grade pipe (even channels of cinderblocks?) with air
blown through could bring the temperature in the greenhouse up a bit
(from what would otherwise be ambient). A water-based approach would
be more efficient but also more costly.

Right now we're planning for several passive heat sources: the water
itself will hold heat, the floor is gravel, and a rocket stove. For
additional heat we use portable propane heaters.

Propane heaters cost a bit to operate. So, you'd like NOT to have
to rely on those -- if you can "store" (or, "prevent from leaking away")
heat that is already available.

On 10/9/2015 4:08 PM, Don Y wrote:
On 10/9/2015 1:40 PM, Muggles wrote:
On 10/9/2015 12:50 PM, Don Y wrote:
On 10/9/2015 9:26 AM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the
proper
angle to capture the winter sunlight and heat. We'll also have vents
and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

What is the year-round soil temperature in your area?
E.g., often there is very little seasonal fluctuation in that
temperature once you are below frost line.

You may find it more economical to "sink" the tanks to that level
to take advantage of the thermal mass of the soil to maintain a
nominal temperature. Likewise for the plumbing.

We can't really sink these tanks into the ground because they are pretty
big and they need to be mobile (in case we need to disassemble the green
house at some point). We are building a rocket stove, though, and it
has venting buried for that.

Can you berm earth around them (or water tanks, etc.)? Anything to add to
the thermal mass that *insulates* them from the surrounding air
temperatures?

We have gravel on top and around it.

[...]
We don't really see much in the way of a water cost increase because the
tanks are filled and the water is re-circulated continuously. Every
couple of weeks we will add water to the main tank, but it's really not
much to maintain water levels. The grow beds are directly above the
water tanks right now, but we may move them and alter the current design
of the water flow once the new green house is ready to move everything
into it (maybe in another couple of weeks).

My point was whether you could afford to "throw away" water by hydrating
the soil in the area to add to the effective thermal mass *in*
the greenhouse. Water is easy to "move"; blocks of stone, not so easy!

Well, the site the green house is on if the former hole that we had our
above ground pool sitting in. It was dished out for the pool and we
never filled it back in, so we're gradually filling it with gravel and
when it rains the water goes the lowest point in the yard which is that
spot. There's about 8 inches of sand where the hole is at and it drains
fairly well, plus there's a drainage pipe that goes out to the street
from that point, too. Between the gravel and sand under it the mass
should hold some heat.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

You can also explore a "poor man's" ground-sourced heat pump system.
I.e., you aren't concerned with bringing that heat into a living space.
So, a below grade pipe (even channels of cinderblocks?) with air
blown through could bring the temperature in the greenhouse up a bit
(from what would otherwise be ambient). A water-based approach would
be more efficient but also more costly.

Right now we're planning for several passive heat sources: the water
itself will hold heat, the floor is gravel, and a rocket stove. For
additional heat we use portable propane heaters.

Propane heaters cost a bit to operate. So, you'd like NOT to have
to rely on those -- if you can "store" (or, "prevent from leaking away")
heat that is already available.




--
Maggie

On 10/9/2015 4:08 PM, Don Y wrote:
On 10/9/2015 1:40 PM, Muggles wrote:
[...]
Right now we're planning for several passive heat sources: the water
itself will hold heat, the floor is gravel, and a rocket stove. For
additional heat we use portable propane heaters.

Propane heaters cost a bit to operate. So, you'd like NOT to have
to rely on those -- if you can "store" (or, "prevent from leaking away")
heat that is already available.



We'd like to not rely on the propane heaters, so we're trying to add
other options. Right now we're adding as many passive heat ideas into
the build and hopefully can incorporate some solar panels soon, too.

--
Maggie

On 10/10/2015 12:06 AM, Muggles wrote:

We'd like to not rely on the propane heaters, so we're trying to add
other options. Right now we're adding as many passive heat ideas into
the build and hopefully can incorporate some solar panels soon, too.


In PRNY, propane is generally cheaper than electric.

Solar heat collection and heat saving options might
work best for you.

-
..
Christopher A. Young
learn more about Jesus
.. www.lds.org
..
..

On Friday, October 9, 2015 at 12:26:10 PM UTC-4, Muggles wrote:
Does anyone know if heating tapes would work for this or not?

You might want to consider the cost of heat tape vs. Roof De-Icing Cables, and which is easier to install. You may need to put the thing on a thermostat to cycle the heat on as needed. If you try heat cable, be mindful of insulating over it, as the heat buildup could possibly cause a fire.

Also, consider insulating any part of the system that can accept it (like maybe the sand filter) with a few removeable polyiso boards all around.

Beyond that, I'm sure you're familiar with thermal mass. So paint anything big and heavy with some black paint and let it sit inside the greenhouse.... maybe paint some pavers black and scatter them around too as stepping stones.

On 10/9/2015 12:54 PM, wrote:
On Friday, October 9, 2015 at 12:26:10 PM UTC-4, Muggles wrote:
Does anyone know if heating tapes would work for this or not?

You might want to consider the cost of heat tape vs. Roof De-Icing Cables, and which is easier to install. You may need to put the thing on a thermostat to cycle the heat on as needed. If you try heat cable, be mindful of insulating over it, as the heat buildup could possibly cause a fire.

Also, consider insulating any part of the system that can accept it (like maybe the sand filter) with a few removeable polyiso boards all around.

Beyond that, I'm sure you're familiar with thermal mass. So paint anything big and heavy with some black paint and let it sit inside the greenhouse... maybe paint some pavers black and scatter them around too as stepping stones.


Roof de-icing cables? hmmm I've never worked with those or heard of them
before. How efficient are they? I'm looking for any idea that might work.

Eventually, we're installing some solar panels to run anything we might
need in the green house, but right now it's all on the grid to the more
efficient the heat source the better.

--
Maggie

On Friday, October 9, 2015 at 4:44:24 PM UTC-4, Muggles wrote:
On 10/9/2015 12:54 PM, wrote:
On Friday, October 9, 2015 at 12:26:10 PM UTC-4, Muggles wrote:
Does anyone know if heating tapes would work for this or not?

You might want to consider the cost of heat tape vs. Roof De-Icing Cables, and which is easier to install. You may need to put the thing on a thermostat to cycle the heat on as needed. If you try heat cable, be mindful of insulating over it, as the heat buildup could possibly cause a fire.

Also, consider insulating any part of the system that can accept it (like maybe the sand filter) with a few removeable polyiso boards all around.

Beyond that, I'm sure you're familiar with thermal mass. So paint anything big and heavy with some black paint and let it sit inside the greenhouse... maybe paint some pavers black and scatter them around too as stepping stones.


Roof de-icing cables? hmmm I've never worked with those or heard of them
before. How efficient are they? I'm looking for any idea that might work..


They are 100% efficient.



Eventually, we're installing some solar panels to run anything we might
need in the green house, but right now it's all on the grid to the more
efficient the heat source the better.

--
Maggie

Converting solar to electric and then back to heat would be nuts.

On 10/9/2015 4:48 PM, trader_4 wrote:
On Friday, October 9, 2015 at 4:44:24 PM UTC-4, Muggles wrote:
On 10/9/2015 12:54 PM, wrote:
On Friday, October 9, 2015 at 12:26:10 PM UTC-4, Muggles wrote:
Does anyone know if heating tapes would work for this or not?

You might want to consider the cost of heat tape vs. Roof De-Icing Cables, and which is easier to install. You may need to put the thing on a thermostat to cycle the heat on as needed. If you try heat cable, be mindful of insulating over it, as the heat buildup could possibly cause a fire.

Also, consider insulating any part of the system that can accept it (like maybe the sand filter) with a few removeable polyiso boards all around.

Beyond that, I'm sure you're familiar with thermal mass. So paint anything big and heavy with some black paint and let it sit inside the greenhouse... maybe paint some pavers black and scatter them around too as stepping stones.


Roof de-icing cables? hmmm I've never worked with those or heard of them
before. How efficient are they? I'm looking for any idea that might work.


They are 100% efficient.



Eventually, we're installing some solar panels to run anything we might
need in the green house, but right now it's all on the grid to the more
efficient the heat source the better.

--
Maggie

Converting solar to electric and then back to heat would be nuts.


The solar power would be used to run pumps.

--
Maggie

On 10/9/2015 9:08 PM, Muggles wrote:



The solar power would be used to run pumps.

Would be interesting to see the thermodynamic math and
financials including payback period for the solar part.
What percentage of the system energy would be derived
from solar electric?

I'm sure there are many success stories, but every time
I've looked at the math, I couldn't see any way to make
solar conversion costs "pencil out"...unless you get
someone else, MY taxes for instance, to subsidize your
system thru tax credits and rebates and raising MY
electricity rates to pay for your use of the grid as storage.

Environmental impact not withstanding, It's very hard
to make solar/electric pay off if you have access to the grid.
Direct heat capture/storage is another matter because the initial
cost can be much less.

I never quite understood the objective. Are you selling
the fish? Growing your own food?

There are some interesting solar heat exchangers for heating
water. It will be too hot for the fish, so you have to have
a separate holding tank. But, if you're adding a lot more
water, it might be more sensible to use it to farm more fish.

I've had some interesting discussions with local solar enthusiasts.
One question I ask is, "if you added up all the time and effort
working on solar and used it to take a job at minimum wage, and
used that to pay for energy, would you be ahead?"
They don't wanna talk about that.

The devil is in the details.
Make sure you do all the math before launching a solar project.

Muggles wrote:
On 10/9/2015 4:48 PM, trader_4 wrote:
On Friday, October 9, 2015 at 4:44:24 PM UTC-4, Muggles wrote:
On 10/9/2015 12:54 PM, wrote:
On Friday, October 9, 2015 at 12:26:10 PM UTC-4, Muggles wrote:
Does anyone know if heating tapes would work for this or not?

You might want to consider the cost of heat tape vs. Roof De-Icing
Cables, and which is easier to install. You may need to put the
thing on a thermostat to cycle the heat on as needed. If you try
heat cable, be mindful of insulating over it, as the heat buildup
could possibly cause a fire.

Also, consider insulating any part of the system that can accept
it (like maybe the sand filter) with a few removeable polyiso
boards all around.

Beyond that, I'm sure you're familiar with thermal mass. So paint
anything big and heavy with some black paint and let it sit inside
the greenhouse... maybe paint some pavers black and scatter them
around too as stepping stones.


Roof de-icing cables? hmmm I've never worked with those or heard of
them before. How efficient are they? I'm looking for any idea that
might work.


They are 100% efficient.



Eventually, we're installing some solar panels to run anything we
might need in the green house, but right now it's all on the grid
to the more efficient the heat source the better.

--
Maggie

Converting solar to electric and then back to heat would be nuts.


The solar power would be used to run pumps.

Solar heating panels would be way more cost effective. The energy you'd collect
in heat/(area or cost) is way more than the cost savings electricity you can
generate to pump. Evacuated tube solar water heating panels are not that
expensive and supposedly work even in cloudy weather.

On 10/9/2015 4:44 PM, Muggles wrote:
Roof de-icing cables? hmmm I've never worked with those or heard of them
before. How efficient are they? I'm looking for any idea that might work.

Eventually, we're installing some solar panels to run anything we might
need in the green house, but right now it's all on the grid to the more
efficient the heat source the better.


Pretty much all electric heaters are the same
efficiency. 5,200 BTU per hour with 1500 watt
consumption.

From what I can see here, the big problem is
heat loss over night. Consider focuss your
efforts there. Vapor barrier to slow evaporation?

-
..
Christopher A. Young
learn more about Jesus
.. www.lds.org
..
..

On 10/10/2015 7:40 AM, Stormin Mormon wrote:
On 10/9/2015 4:44 PM, Muggles wrote:
Roof de-icing cables? hmmm I've never worked with those or heard of them
before. How efficient are they? I'm looking for any idea that might
work.

Eventually, we're installing some solar panels to run anything we might
need in the green house, but right now it's all on the grid to the more
efficient the heat source the better.


Pretty much all electric heaters are the same
efficiency. 5,200 BTU per hour with 1500 watt
consumption.

From what I can see here, the big problem is
heat loss over night. Consider focuss your
efforts there. Vapor barrier to slow evaporation?


OK I'll add that to my list of ideas/solutions. Thanks!

--
Maggie

On 10/10/2015 5:40 AM, Stormin Mormon wrote:
On 10/9/2015 4:44 PM, Muggles wrote:
Roof de-icing cables? hmmm I've never worked with those or heard of them
before. How efficient are they? I'm looking for any idea that might work.

Eventually, we're installing some solar panels to run anything we might
need in the green house, but right now it's all on the grid to the more
efficient the heat source the better.

Pretty much all electric heaters are the same
efficiency. 5,200 BTU per hour with 1500 watt
consumption.

From what I can see here, the big problem is
heat loss over night. Consider focuss your
efforts there. Vapor barrier to slow evaporation?

It takes 1 BTU to heat a pound of water 1 degree. Let that
pound of water *evaporate* and you've LOST ~1000BTU's!

On 10/10/2015 12:48 PM, Don Y wrote:
On 10/10/2015 5:40 AM, Stormin Mormon wrote:
From what I can see here, the big problem is
heat loss over night. Consider focuss your
efforts there. Vapor barrier to slow evaporation?

It takes 1 BTU to heat a pound of water 1 degree. Let that
pound of water *evaporate* and you've LOST ~1000BTU's!


I'd have to look it up, but I think the latent
heat of fusion is 86 BTU per pound, and the
heat of vaporization is about 550. But, it's
been a long time since I needed that.

-
..
Christopher A. Young
learn more about Jesus
.. www.lds.org
..
..

On 10/10/2015 11:48 AM, Don Y wrote:
On 10/10/2015 5:40 AM, Stormin Mormon wrote:
On 10/9/2015 4:44 PM, Muggles wrote:
Roof de-icing cables? hmmm I've never worked with those or heard of them
before. How efficient are they? I'm looking for any idea that might
work.

Eventually, we're installing some solar panels to run anything we might
need in the green house, but right now it's all on the grid to the more
efficient the heat source the better.

Pretty much all electric heaters are the same
efficiency. 5,200 BTU per hour with 1500 watt
consumption.

From what I can see here, the big problem is
heat loss over night. Consider focuss your
efforts there. Vapor barrier to slow evaporation?

It takes 1 BTU to heat a pound of water 1 degree. Let that
pound of water *evaporate* and you've LOST ~1000BTU's!


As it evaporates, does it not warm the surrounding air?

--
Maggie

On 10/10/2015 9:48 AM, Don Y wrote:
On 10/10/2015 5:40 AM, Stormin Mormon wrote:
On 10/9/2015 4:44 PM, Muggles wrote:
Roof de-icing cables? hmmm I've never worked with those or heard of them
before. How efficient are they? I'm looking for any idea that might
work.

Eventually, we're installing some solar panels to run anything we might
need in the green house, but right now it's all on the grid to the more
efficient the heat source the better.

Pretty much all electric heaters are the same
efficiency. 5,200 BTU per hour with 1500 watt
consumption.

From what I can see here, the big problem is
heat loss over night. Consider focuss your
efforts there. Vapor barrier to slow evaporation?

I don't know anything about farming fish, but don't you need
some water/air exchange to keep the oxygen level tolerable to the fish.
If you just block the surface, what keeps the fish alive?

It takes 1 BTU to heat a pound of water 1 degree. Let that
pound of water *evaporate* and you've LOST ~1000BTU's!

On Fri, 09 Oct 2015 11:26:04 -0500, Muggles wrote:


We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

The water heater idea sounds like something worth pursuing. Would
there be an easy way to cover the tanks during the night? Truckers use
tarps to cover loads. Some are more or less automatic. Some folks here
have pools. Would a pool cover help?


--
Using Opera's mail client: http://www.opera.com/mail/

On 10/9/2015 5:58 PM, Dean Hoffman wrote:
On Fri, 09 Oct 2015 11:26:04 -0500, Muggles wrote:


We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

The water heater idea sounds like something worth pursuing. Would
there be an easy way to cover the tanks during the night? Truckers use
tarps to cover loads. Some are more or less automatic. Some folks here
have pools. Would a pool cover help?



We can use tarps to cover the tanks, but we also have to keep the plants
healthy, too, and the ambient air temps can't drop too low.

--
Maggie

On 10/9/2015 12:26 PM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?


Doubt it. The common heat tapes are designed to keep water
(barely) over the freezing temp. I'd expect them to work
well below the 60F you want.

With this much water, I'd check with pet stores and see
what they think. Propane is usually cheaper than electric
as a fuel source.

Perhaps a propane residential water heater, and tempering
valve?

-
..
Christopher A. Young
learn more about Jesus
.. www.lds.org
..
..

On 10/10/2015 11:42 AM, Stormin Mormon wrote:
On 10/9/2015 12:26 PM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?


Doubt it. The common heat tapes are designed to keep water
(barely) over the freezing temp. I'd expect them to work
well below the 60F you want.

With this much water, I'd check with pet stores and see
what they think. Propane is usually cheaper than electric
as a fuel source.

Perhaps a propane residential water heater, and tempering
valve?

Would a water heater like that end up costing more in powering it?
--
Maggie

On 10/10/2015 2:12 PM, Muggles wrote:
Does anyone know if heating tapes would work for this or not?


Doubt it. The common heat tapes are designed to keep water
(barely) over the freezing temp. I'd expect them to work
well below the 60F you want.

With this much water, I'd check with pet stores and see
what they think. Propane is usually cheaper than electric
as a fuel source.

Perhaps a propane residential water heater, and tempering
valve?

Would a water heater like that end up costing more in powering it?


My experience with heat, is that propane is
cheaper than electric. In any, or, whatever
form.

-
..
Christopher A. Young
learn more about Jesus
.. www.lds.org
..
..

On 10/10/2015 3:43 PM, Stormin Mormon wrote:
On 10/10/2015 2:12 PM, Muggles wrote:
Does anyone know if heating tapes would work for this or not?


Doubt it. The common heat tapes are designed to keep water
(barely) over the freezing temp. I'd expect them to work
well below the 60F you want.

With this much water, I'd check with pet stores and see
what they think. Propane is usually cheaper than electric
as a fuel source.

Perhaps a propane residential water heater, and tempering
valve?

Would a water heater like that end up costing more in powering it?


My experience with heat, is that propane is
cheaper than electric. In any, or, whatever
form.


ok thanks for the info.

--
Maggie

Muggles wrote:
On 10/10/2015 3:43 PM, Stormin Mormon wrote:
On 10/10/2015 2:12 PM, Muggles wrote:
Does anyone know if heating tapes would work for this or not?


Doubt it. The common heat tapes are designed to keep water
(barely) over the freezing temp. I'd expect them to work
well below the 60F you want.

With this much water, I'd check with pet stores and see
what they think. Propane is usually cheaper than electric
as a fuel source.

Perhaps a propane residential water heater, and tempering
valve?

Would a water heater like that end up costing more in powering it?


My experience with heat, is that propane is
cheaper than electric. In any, or, whatever
form.


ok thanks for the info.

That will depend completely on the relative costs of propane and electricity
where you live.

"
a.. Multiply the oil heat price per gallon by 0.663 to give the equivalent price
per gallon of propane
a.. Multiply the natural gas delivered price per therm by 0.92 to give the
equivalent price per gallon of propane
a.. Multiply the electricity price per kWh by 27.0 to give the equivalent price
per gallon of propane "
from http://www.thefrugallife.com/heating.html

On Saturday, October 10, 2015 at 2:12:42 PM UTC-4, Muggles wrote:
On 10/10/2015 11:42 AM, Stormin Mormon wrote:
On 10/9/2015 12:26 PM, Muggles wrote:

We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?


Doubt it. The common heat tapes are designed to keep water
(barely) over the freezing temp. I'd expect them to work
well below the 60F you want.

With this much water, I'd check with pet stores and see
what they think. Propane is usually cheaper than electric
as a fuel source.

Perhaps a propane residential water heater, and tempering
valve?

Would a water heater like that end up costing more in powering it?
--
Maggie


Round in circles we go, with no definition of the actual problem.
Cost more in power than what?

On 10/11/2015 7:36 AM, trader_4 wrote:
On Saturday, October 10, 2015 at 2:12:42 PM UTC-4, Muggles wrote:

Would a water heater like that end up costing more in powering it?
--
Maggie


Round in circles we go, with no definition of the actual problem.
Cost more in power than what?


But, dear, you NEVER tell me ANYTHING!

-
..
Christopher A. Young
learn more about Jesus
.. www.lds.org
..
..

Muggles posted for all of us...



We're re-building our hoop green house and using wood this time. We
have a aquaponics system where we raise fish, pump the fish water into
grow beds so the plants and plant media can filter the water, pump that
water into a sump and then that water goes to a large rock and sand
filter before it's pumped back into the fish tanks.

We're looking for a way to keep the water in the tanks warm in the
winter without it costing us an arm and a leg to heat the green house
itself. We're going to have about 800 to 1000 gallons of water in the
green house tanks, plus have passive solar heat from the ground that'll
have a thick layer of gravel in addition to having windows at the proper
angle to capture the winter sunlight and heat. We'll also have vents and
windows we can open at the peak of the green house to vent moisture and
too much hot air when needed on warmer days.

The problem is that if we heat the greenhouse along with using water
tank heaters the temps can drop dramatically in the greenhouse and
plants and fish don't do well if the temps are too drastic at night, so
I was thinking of using heat cables/tapes around the pvc pipes that
connect all the water flowing from tanks to plants to sump to filter vs.
using in tank water heaters.

We're also hoping for a solution that'll cost less to power and at the
same time keep the temps more stable in the green house. All the walls
and roofs are being insulated, too.

Does anyone know if heating tapes would work for this or not?

I don't think the pvc pipe would be a good conductor of the heat given off
by the tape. Perhaps heater in the fish tank would be best.

--
Tekkie