By  Steven Stiles

Solar thermal space cooling is, one might say, a little known offshoot of the solar energy movement. Most of the present hoopla goes toward photovoltaics, solar thermal electric, or even solar thermal heating. So where does solar space cooling come in? Solar cooling systems are relatively expensive to purchase and install; they are also rather complex.

Known as Thermally Activated Cooling Systems (TACS), there are two types of solar space cooling systems: solar absorption and solar desiccant systems. Because of their high cost and complexity, cooling systems exist primarily in large scale, commercial arenas. Even on such a large scale, solar cooling systems are used to provide just 30% to 60% of a building’s cooling load, according to the Department of Energy. What needs remain are usually provided by systems driven by natural gas.

Solar Absorption Systems

• Absorption systems use heat from the sun to separate a refrigerant fluid (e.g., water vapor) from an absorbent one (e.g., lithium bromide salt). That evaporated refrigerant is then condensed in a chiller to produce cold water. This chilled water is then pumped into coils over which indoor air is blown and cooled.
• There are single-effect and double-effect absorption systems. Double-effect systems use the heat twice in the series and are twice as efficient but require nearly twice as much heat.

Solar Desiccant Systems

• Desiccant systems use solar thermal energy to regenerate desiccants which dry out the air, thus producing a cooling effect of its own. Desiccants are typically solids and sit on a wheel (think of a steamboat’s paddlewheel) that rotates into the stream of air flowing into the home. The desiccants remove the humidity, and subsequently cool that air. As the desiccants then rotate out of the incoming air, thermal energy from the solar collectors re-dries them and the process is repeated.

Solar space cooling is still a very new technology and not yet competitive with its conventional counterparts. For now, its best bet is in conjunction with other systems such as solar hot water or solar space heating systems. At this point of combined effort, the solar system comes close to competitive. Beside high initial costs, solar space cooling systems need a high ration of sunlight and heat to work. This limits the areas where it can be used efficiently, but also makes it useful where it is needed most. These needs will likely drive solar cooling innovations, especially in areas such as Africa, Australia, and the Southwestern United States.

Renewable & Alternative Energy Resources: http://www.alternativeenergybase.com
Steven Stiles is a technology writer for CalFinder’s Residential Solar Power website; an excellent resource for information on residential solar energy systems and for finding certified solar contractors nation wide.

by Michael Geoffrey

Taking care of the Earth and reducing both global warming and climate change is everyone’s responsibility. While doing things like recycling is good, there are additional ways in which you can help. By conserving water when gardening, you can both help protect the environment and save yourself some money. You may be surprised to know that conserving water in your garden may actually help you plants to grow healthier.

Conserving Water: How to Do It

The plans you choose to grow in your garden will greatly affect how you conserve water. You will want to choose plants that can handle limited amounts of water. By selecting the right plants, you will be able to greatly reduce the amount of water that you will need to use in your garden. It will also mean less work for you in maintaining your garden. Read the rest of this entry »

by Amelia Yap

Your New Years resolutions should include at least one green features for the coming year. 2009 is the year to go green — It’s never been easier. With more and more people improving their habits, it’s become more appealing than ever to implement an environmentally friendly lifestyle. Green solutions don’t have to mean expensive alternatives. With the popularity of going green on the rise, it’s become cheaper and easier to improve your living habits. For instance, you should try and unplug all the electronics when they aren’t in use. Similarly, try turning off lights you are not using. Try reducing your heater use, and wear extra layers of clothes to keep warm. You should also try and switch from toxic and chemical cleaners to the eco-friendly and home made alternatives to improve the quality of your indoor air. Read the rest of this entry »