The same energy that heats buildings up can also cool them down with STC. This clean, innovative, technically sound renewable space conditioning system delivers to building owners clean, load-following, peak-shaving and energy-saving system to building owners by hybridizing two basic, proven technologies:

• Concentrating parabolic/evacuated tube/flat-plate solar collectors --which make hot water to drive heat-driven chillers
• Absorption or adsorption chillers which generate chilled water for space conditioning

STC systems are perfect for green building owner/operators and other people just interested in contributing to a cleaner, healthier environment. Their benefits include:

• Cleaner air + less global warming
  Renewable cooling = no CO 2, SOx, NOx, or PM (as opposed to electricity needed for electric chillers)
• Less wasted water
  STC systems use a closed water loop = no water lost (as opposed to evaporative cooler; also, there is far less water consumed in processing coal for electricity generation)

Solar Thermal Collectors

NET represents only the most efficent, highest performing flat plate, evacuated tube, and concentrating parabolic solar collectors to drive chillers. Collector thermal performance ratings - conducted by the Solar Rating and Certification Corporation (SRCC) - compare the efficiency and economics of flat-plate and evacuated tube collectors. To compare the thermal efficiency of different collectors, look at the Btu/(ft2/day) rating; the higher the number, the better the solar energy collection efficiency and the fewer square feet of collector area needed to do the job.

When the sun's not shining, the chillers can still operate using heat from hot boilers or onsite generators, or chilled water storage can act as a buffer for low insolation periods.

Chillers & Desiccant Dehumidification Systems

Although it may seem counterintuitive to put heat into a machine in order to get cold air out, it makes more sense to think of heat as a form of energy used to remove heat from a building. Absorption chillers use heat instead of mechanical energy to provide cooling. A thermal compressor consists of an absorber, a generator, a pump, and a throttling device, and replaces the mechanical vapor compressor. In the chiller, refrigerant vapor from the evaporator is absorbed by a solution mixture in the absorber. This solution is then pumped to the generator. There the refrigerant re-vaporizes using a waste steam heat source. The refrigerant-depleted solution then returns to the absorber via a throttling device. The two most common refrigerant/ absorbent mixtures used in absorption chillers are water/lithium bromide and ammonia/water.

NET currently represents the following solar thermal energy-driven technologies:

• Thermax absorption chillers, manufacturers of high-COP chillers, with over 2000 chillers in operation in the Americas (over 100 installations in California), Europe, Australia, the Middle East, Denmark, Indonesia, etc.
• Adsorption chillers that uses only water and desiccant gels to cool buildings, and that can operate with varying amounts of solar Btu input. Ideal for variable insolation areas.
• Desiccant dehumidification systems for hot/humid climates. Used in tandem with absorption chillers, desiccants can greatly increase the efficiency with which intake air can be cooled.
• Ammonia chillers for sub-freezing cooling and ice production--which could be used in thermal energy storage applications.