Except for the costal region of Peru, deserts typically have very low humidity and hence a low greenhouse effect. This means the nights get quite cold as heat is radiated to the 2 degree absolute blackbody of space. To capitalize on that only requires creating a radiator that can be fed heat from an insulated body of water. Of course one can collect heat with the radiator and feed it into a hot water heater.

Insulate a tank of water. Put a heat valve tube through the insulation at the top. Do the same with another insulated tank of water except the tube comes out the bottom. Connect the top of the bottom tube to the bottom of the top tube. At this junction put a big chunk of metal with a hole at its side. In this hole put the end of a heat pipe that also runs down the length of a black body radiator.

During the day, the radiator heats up, hopefully above the temperature of the hot water. The heat pipe delivers heat to the heat valve which takes it to the hot water tank. At night the radiator radiates its heat to the black body of the sky, it cools off, hopefully to below the temperature of the cold water. Heat will then be delivered to the heat pipe via the lower heat valve.

With a sufficient area of radiator and volume of water, enough hot and cold water should be created to climate control relatively large greenhouses. If cold enough, the cold water ought to be able to cause condensation reducing the humidity in the greenhouse with a simple water tower. This would also recover some of the evaporated water and creat temperature differences for air flow.
-- cjacks, Oct 13 2005

Madai’s domed farm. Domed_20Farms
A concept in need of this. [cjacks, Oct 13 2005]

Can you repeat the part about the water please?

/2 degree/ What scale? Why 2?
-- Texticle, Oct 13 2005


Is this not an elaboration on a dew point distillery? The classic water-collection device: dig hole, place cup in hole, cover hole with plastic sheet, place rock on plastic sheet directly over cup, and wait for sun to heat plastic sheet.
-- reensure, Oct 13 2005


I guess you want to use hot water to heat the greenhouse at night, and cold water to cool the greenhouse during the day.

It is well known that a large body of water acts as a temperature stabiliser. If the same amount of water, that you propose, was simply stored in the greenhouse in long radiators, then the temperature in the greenhouse would be more stable without resorting to complex systems. If the water system was open, then condensing the vapour at night (on the glass?) would release yet more heat.

It would be a little easier if you could draw diagrams of your ideas, and link to them.
-- Ling, Oct 13 2005


I had intended to store the water in underground tanks. (actually pipelines when taken to design endpoint). This would allow for a very large amount of water without disturbing the plant growing area. To get the heat from underground to above the greenhouse envelope passively is where the heat valve/radiator complex comes into play.
The hot water part isn’t as necessary in a desert but the symmetry of the solution was worth pointing out.
I would like to post drawings but can’t really afford to pay for a website just for such what. Do you know of a place that could be done? Somewhere like this place but allowing pictures.
-- cjacks, Oct 13 2005


The temperature of space is slightly below 2 degrees Kelvin. Earth radiates the heat it gets from the sun into that blackbody. On nights with very low humidity, very frequent in most deserts, you can almost feel it. Try pointing one of those “in ear” thermometers at the sky, and the ground, on a dry night, or mounting two thermometers on opposite sides of a piece of cardboard and placing it as a bridge between two back to back lawn chairs in the yard.
-- cjacks, Oct 13 2005


I have linked to Madai’s domed farm.
-- cjacks, Oct 13 2005


anything involving heat pipe is welcome. this technology really fascinates me & i believe, many of its applications are yet to be explored.
-- vedarshi, Oct 13 2005


//I would like to post drawings but can’t really afford to pay for a website just for such what. Do you know of a place that could be done? //
If you send them too me and they are not super huge I can chuck them on the web for you. Email address on profile.
-- gnomethang, Oct 13 2005



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