Using excess heat.

[Eric Warwick]

There has been a large flight from traditional grow-lights to Light Emitting Diodes, or LED's, but in cooler climates heat is generally needed, before I rant I'm going to stop myself with a few laws of thermodynamics that makes this question insane to a physicist, anyways since the large heat producers, please correct me here, are the best for fruiting plants. If so what tools can we use to capture the thermal energy and excite some particles where needed? 

Help is greatly appreciated.   

[TCLynx]

I know there are liquid cooled grow lights though you can't pump system water directly through the cooling tubes since they will clog.

[Eric Warwick]

Would a separate system of water that goes through the fish tank after cooling the light work?

TCLynx said:

I know there are liquid cooled grow lights though you can't pump system water directly through the cooling tubes since they will clog.

[TCLynx]

I expect any sort of heat exchange method could work though it might not be all that efficient.

Like if you had coils of tubing under a raft bed that circulated with the cooling coils of the lights but didn't actually mix the water.

[Eric Warwick]

I think my question made some physicists cry.

TCLynx said:

"I expect any sort of heat exchange method could work though it might not be all that efficient."

 

[TCLynx]

[the mad german]

Capturing thermal energy that just radiates isn't a problem. I suspect your question is storing and reutilizing the heat for later use?

I guess it really depends on what type of scale your looking at. Small scale setups the storage amount would be depleted rather fast.

On a large scale setup, rocks 2-3" in diameter buried in an enclosed insulated box filled with rocks below your greenhouse running the entire length is idea.

With 2 squirrel cage fans 1 pushing and 1 pulling, The return fan would pull from a pitched insulated channel above the lights and push into the rock beck below, the other fan would pull from the gravel.

During the day this would allow the earths cool temp to help cool from excessive greenhouse heat, and at night the rocks warm from the day would in return give off the heat picked up during the day.

Sizing would be the biggest issue and depending on the air changes per hour, your storage and fans would have to be sized accordingly.

[Eric Warwick]

"I suspect your question is storing and reutilizing the heat for later use"—yes that's part of my question, and also, in general, making sure heat does not go to waste; examples of techniques are but not limited to, proper insulation, conducting technologies—could be as simple as a plastic tube with heat retentive fluid in it—and thermal masses. 

 

I hope your idea is in the creative commons, because some tinkering might occur.  

the mad german said:

Capturing thermal energy that just radiates isn't a problem. I suspect your question is storing and reutilizing the heat for later use?

I guess it really depends on what type of scale your looking at. Small scale setups the storage amount would be depleted rather fast.

On a large scale setup, rocks 2-3" in diameter buried in an enclosed insulated box filled with rocks below your greenhouse running the entire length is idea.

With 2 squirrel cage fans 1 pushing and 1 pulling, The return fan would pull from a pitched insulated channel above the lights and push into the rock beck below, the other fan would pull from the gravel.

During the day this would allow the earths cool temp to help cool from excessive greenhouse heat, and at night the rocks warm from the day would in return give off the heat picked up during the day.

Sizing would be the biggest issue and depending on the air changes per hour, your storage and fans would have to be sized accordingly.

[the mad german]

Anytime you utilize a heat retaining fluid you have efficiency loss, depending on what your using, then throw in a heat exchanger and the BTU curve drops another 10-15%.  Short of having a closed loop system (something built in an insulated enclosure like an old discarded deep freezer) Or an insulated basement.Your return on investment for BTU gain would take a long time to repay itself.

If you were to utilize a heat recovery system copper tubing or piping above your lights in either a heat exchanger plate fashion or a spiral tube would be your best bet based on coppers heat transfer efficiency rate.

You could then take that to an insulated tank. Which would then have to have another set of coils, blower pump and a fan to reheat the air in the growing space.Or you could just use a pump, grab the heat from the coils during the day sending it into the storage tank, then at night send it back out to coils below the grow bed and heat the soil through convection.

It can be done, its just a matter of cost. If you wanted to get right down to the nitty gritty and are serious and have a confined growing area like a basement or room, a heat load calculation would be able to tell you exactly how many BTUs would be needed to not only heat the space or grow area, but what would be needed for storage as well.

HVAC, energy management and controls are my specialty. Theres a rule of thumb for greenhouse energy efficiency thats just dieing for me to push the envelope on if it weren't for cost and financing.Its been 1 of my lifelong dreams to build a completely self-sustainng greenhouse for year round applications in cold weather climate.

[TCLynx]

Just one issues here, copper in contact with any system water is a no-no since recirculating systems will build up toxic levels of copper for the fish.

[Eric Warwick]

Unless you put something over it, or put the coils under the tank, maybe?

TCLynx said:

Just one issues here, copper in contact with any system water is a no-no since recirculating systems will build up toxic levels of copper for the fish.

[TCLynx]

I know people who have used coils under the liner of a raft bed for hydronic heating, it does work.

[the mad german]

Sorry I should've said under the tank or bed instead of soil. Hydroponics is actually a very efficient way of heating with respect to heat transfer and getting the most bang for your buck or I should say complete utilization of the existing BTUs or extraction of them from the water.

It still comes down to storage and having a system big enough to draw off of it all night long.

TCLynx said:

Just one issues here, copper in contact with any system water is a no-no since recirculating systems will build up toxic levels of copper for the fish.