On Saturday, October 10, 2015 at 11:52:12 PM UTC-4, Muggles wrote:
On 10/10/2015 4:21 PM, Tekkie® wrote:
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.


Right now we have some large aquarium heaters, but they use a lot of
electricity.

--
Maggie

Any electric heating element is 100% efficient in producing heat.
If that aquarium heater is producing X heat for Y KWH, any
other electric heating element you replace it with, if it produces
5X heat is going to take 5Y KWH.