Thermal banking Greenhouse

[keithrs]

I have been doing some research on greenhouse and greenhouse designs as I plan on building a smallish greenhouse soon. I ran across this video on thermal banking to reduce your heating and possibly cooling bills if designed alittle different. This video is made for soil growers but I think the concept can translate to orchid growing to reduce some cost of running a greenhouse.

Thermal banking

 

[SlipperFan]

Go for it! It will be interesting to see how you might apply these concepts to your "smalllish" greenhouse.

 

[Ray]

Geothermal might be easier and less-expensive to implement.

There was an article in an old AOS Bulletin about a guy who dug a couple hundred feet of 6' deep trench, laid up a series of unglazed clay sewer pipe as the ductwork, and buried it again after connecting the ends to the atmosphere and greenhouse interior.

By drawing the air into the GH though the buried duct, it was a constant 63°-65° - certainly enough for heat in winter, and excellent cooling in the summer. The unglazed pipe was moistened by the soil, so humidified the dry, winter air, and condensed some of the excess summer humidity out.

I am really tempted to do that myself, but my next-door neighbor just tried digging a 500', 6' deep trench for home geothermal heating, and hit too much rock, so he ended up paying for two 300' water wells, instead.

 

[keithrs]

I'll be honest I'll need cooling more than I'll need heat. I have two ideas running through my head. One is geothermal and the other is a cooling tower.

I was thinking if I dug out a 4' hole 8'x14'; just inside the footings. Layed down PEX, covered with 3' of DG base, than wepping tile covered with 3/8 smooth rock. The wepping tile would be used to blow warm air from the peak into the floor for heating. I'm thinking if I have to run a small heater that heated air that would also be pulled through the floor reducing the size heater need. The PEX will be used for cooling. I'm going to pump water(maybe coolant) threw the PEX to an air handler that I have sitting in the back. My thinking is that the water that gos into the ground will help keep the soil cool. But I'm still not sure it I would have enough cooling for a 10'x16' greenhouse on a 110 deg day.

The water tower would be a big water fall that would work like a evap cooler only the water would go to an air handler instead of a fan blowing through the pad. This how alot of office building cool there building here.

Maybe I'll do a combo of both.

 

[Lycaste53]

What about a cooling floor? Circulation of cool water in pipes under the floor? In Germany there ia a system of floor heating availabe ( I don´t have it, but it exists) which can also be used for cooling.

 

[keithrs]

Yes.... I may run cool air under the floor as well. But I don't think it will have much of an effect on cooling... Cool air sinks. Heating the floor works well because warm air rises.

 

[Lycaste53]

There is a difference between water and air, what concerns the capacity of beeing able to retain energy (temperature). It needs much more energy, to raise temperature of 1cbm water than of 1cbm air. It needs much less energy to cool down 1 cmb air than 1 cbm water. That´s the reason why we use cold water or ice, to cool down champaign. It works better and faster.
Cold water is much more efficient in cooling down hot air, than cool air is efficient in cooling down hot water. It is a question of retention/ storage capacity of the media you use. Water ´sucks´much more temperature than air.
I hope you understand what I want to explain, sometimes my english vocabulary is not sufficient to explain properly physical aspects.