Absorption Cooling
Actually, air conditioners have used absorption-cooling technology from the introduction of air conditioning. In fact, this type has been around since before air conditioners first arrived on the scene. Over 150 years back, before the invention of the electric light bulb, absorption chillers were making ice. Back then, the ice was stored for cooling uses during cloudy weather.
Early coolers used ammonia and water. Later commercial refrigerants such as a hydroflourocarbons were common along with natural gas firing to heat the water. However, the discovery that fluorocarbons were harmful to the atmosphere curtailed their use. Today the use of lithium bromide and granulated silicate gel for refrigerants is common place, along with other safe materials.
As for absorption solar cooling, solar collectors generate the heat required to drive the cooling systems rather than electricity. Simply, absorption-cooling systems use solar thermal energy to power the cooling process. No electrical energy is wasted. The pumps and ventilation fans draw electrical energy from Solarvoltaic panels.
In practice, solar heated water starts a thermal dynamic process. This action involves low-pressure chambers for cooling the water to about 45°F. Thus chilled, the water flows through an arrangement of copper tubing. Then a ventilation fan blows air across the tubing into the home, and small pumps circulate the water, otherwise the system is basically passive.
Solar absorption cooling is ideal where hot weather and lots of sunshine is dominant. Hot arid desert environments are ideal for home cooling systems. The more energy from the sun is available, the more the cooling will there will be.
For more information on absorption cooling systems, go to links section at the bottom of the page.
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At first, the idea of solar cooling is; hmmm… actually cooling things down with the sun is - well… let me put it this way, maybe you could say, it’s sort-a oxymoronishy. Anyway, it’s true, using solar thermal energy for cooling is not new at all. In fact, using the sun’s energy to chill stuff is old science. Hmmm, I think that sums it up – yap that should do it! But...
Everybody knows, a variety of systems is cooling things down in buildings everywhere. And everyone is familiar with ordinary air conditioners. For example, evaporative swamp coolers set atop many a home. It may seem a bit strange to think of the sun cooling anything, but it’s true, solar cooling does so quite efficiently.
What’s cool (no pun intended), solar cooling cycles are similar to oceans tides, unlike solar heating, this kind of cooling doesn’t require storage devices. Cool air output increases and decreases with the availability of solar thermal energy, just as lunar phases affect tidal movements. As a result, electrical power requirements reduces as heat availability increases.
The main difference between the two is an air conditioner is set up for only cooling. While the heat pump provides both heating and cooling. Heat pumps are the most effective in temperate climates. Colder climates result in condenser icing. Ice prevents unit heating.
With extremely dry air, the injection of humidity provides for evaporation. This process actually does lower the temperature. The process continues, the desiccant regenerated (desorbed) using solar thermal energy, and the cycle continuously repeats itself. This is a simple example of a desiccant cooling system.
A swamp cooler is a typical evaporative system. It uses a fan to pull hot dry air through water-wetted pads positioned in each of the four sides of a box like device. A steady stream of water drawn from the reservoir at the bottom keeps the pads wet. As the water accumulates, a small pump sends it back to the top where it continuously drips down through the pads. From there, cool air blows into the dwelling, where common temperature reductions are 20 to 30°F.
In practice, refrigeration takes place by pumping heat out of a closed insulated chamber so that its temperature is less than that of the surrounding air. Solid state cooling is not solar cooling, but wait. Thermoelectric refrigeration supplied by solar photovoltaic power is a fantastic way to keep drinks and the potato salad cold.
