Zero Energy Heating and cooling

DanDMan

Here is an idea that seems like it would work with aquaponics. The idea has been used to make a zero energy house. It uses this method to both heat and cool.

Quote:

The roofpond idea was originated by Harold Hay and first embodied in the Skytherm House at Atascadero, CA.

A roof pond system can provide both radiant cooling and radiant heating with no alteration of its components, simply by changing the operating cycle. It consists of a large mass of water contained in a plastic bladder and liner, lying on a metal ceiling deck, which should be corrugated to increase the thermal coupling with the house below. Above the water lies a movable insulation panel. The water mass above the metal ceiling collects, stores and dissipates heat energy to maintain constant comfort conditions inside the building. Typical roof pond systems use a water mass from 100 mm to 250 mm (4 to 10 inches) in depth.

The primary cooling mode for a roof pond system is radiation, which can cool the water significantly below wet bulb temperature. The night sky (on days with clear skies and low humidity) gets very cold, well below freezing if you aim an infrared thermometer at it. So, the "sky cooling" effect is achieved by exposing a warm mass to the night sky and preventing the daytime sunshine from reheating it (via the movable insulating panel).

Because of its reliance on radiative cooling, the Skytherm concept is best suited for areas of low humidity and clear nights.

Source: Roofpond Simulation Software Manual at http://suntzu.larc.calpoly.edu/ehhf/

tamo42

Pretty interesting. Wouldn't work well in my climate (humid, often cloudy), but still interesting!

steve

good one dan..........

i've often thought about making a green house with a reflective outer that could be automatically retracted.............

a little OT, but so people realise that the traditional glass greenhouses used the fact that glass transmits IR and visible wavelengths from the sun but reflects the (longer or is it shorter?)IR wavelengths from the plants? hence green house effect.

i often wonder if the new plastic films exhibit the same phenomenon or if they are primarily based on insulation ie. double skinned air filled...........

DanDMan

The primary way the heat is removed is black body radiation into the night sky. That is what makes this interesting. It is not just evaporation. However, moisture in the air reflects heat back. They demonstrated this to work in Kansas as well as arid climates.

Now, I can not build a building with a pond on top of it, but I can use a pump to move water between a large outside tank and indoor barrels. That seems more reasonable than covering it with insulation every day. I am going to test this idea this summer just to see how well this does in a humid east Texas climate.

TCLynx

Dan, this is rather along the lines of using a solar pool heater and a radiant pool chiller. A bunch of us are working on very similar ideas here. The radiant cooling might not be nearly as effective in humid climates but may still be of some value. I kinda like the idea of the pool on the roof but unfortunately, I don't have a flat roof nor am I ever likely to.

Many people use water as thermal mass and it is handy that it flows so is easily pumped to where it can be heated or cooled as the need of the season.

Backyard Aquaponics A place to discuss aquaponics

Zero Energy Heating and cooling

Backyard Aquaponics
A place to discuss aquaponics