About 4 years ago, I had an inexpensive 8X10 green house and my major problem was overheating. If I let the sun beat me up in the morning, my plants were baked before my breakfast was cooked. It was amazing how hot how fast that little greenhouse could get.
Suppose you had two greenhouses built side by side......one for growing plants and one for building up and storing heat when the sun was shining to be piped over to the active greenhouse. The heat sink greenhouse may not have to be very large. Experimentation would be necessary to determine what size heat sink greenhouse would be necessary to supply heat to whatever size of active greenhouse you are using. Maybe more than one small heatsink greenhouse could be spaced out alongside the active greenhouse.
What could be used as a heat sink? Rocks comes to my mind because I live on a ridge top in central Texas. Before this lot could be built on, all the surface rocks had to be picked up. Im just talking about the surface rocks. I have attached a picture of just the surface rocks here that were picked up from 6/10ths of an acre and are now stacked on the backside of my lot. These white limestone rocks could be painted black to better absorb heat and stacked inside a heat sink greenhouse for storing heat. A fella up the road from me used his surface rocks to build "fence posts". Thats fairly common here in the hill country. You just form either 4 foot or six foot high hog fence wire into a 3 to 4 foot diameter standing on end and throw rocks into it. PRESTO.......a rock fence post. Afew similiar little structures in a heatsink greenhouse could store a lot of heat. Another possibility is the cheapest gravel, rocks from l to 2 inches in diameter. And of course, there is always water storage. Let your imagination run wild. I get a kick out of the idea of using waste products like the surface rocks from my yard.
As to the heat sink green house, I am thinking that I would wont to keep it closed up most of the time for maximum heat absortion. It would also be possible to put an automatic vent in it to control the amount of heat buildup. Whatever works in your climate. I dont think PVC pipe will take the amount of heat I am visualizing. So wood or metal conduit would be better. Whether the cheap 6 mil plastic from home depot would take the heat or not I dont know. It might last one season. The structure Im thinking about could certainly become cost effective in reducing (or, in some climates) completely replacing your present heat costs.
It is getting colder and windy outside and Im cooped up in here thinking crazy thoughts. For instance, a few drying shelves in that heat sink green house and you are in the dried vegetable business. Just think......any tomato that aint purty enough for customers........just slice and dry that sucker!! Put a sign out in front of your house DRIED TOMATO'S SOLD HERE. GET THEM WHILE THEY ARE HOT.
