A High Efficiency Air Conditioner for Humidity Control in Residences

72716-Air conditioners now on the market are very poor at controlling indoor humidity. In some buildings, high indoor humidity creates health problems and leads to the growth of mold and mildew; in other buildings, energy is wasted as the building owner overcools the indoor space to try to create comfortable conditions. A high efficiency air conditioner that also provided superior dehumidification would restore healthy indoor conditions while significantly reducing energy use. This project will incorporate advanced liquid-desiccant technology into an electric vapor-compression air conditioner that: (1) provides more than twice the dehumidification of a conventional system, (2) reduces compressor power by 24% or more, and (3) is easy to install on a residence. A 6,000 Btu/h breadboard model of the liquid-desiccant vapor-compression air conditioner was built and tested in Phase I. It was shown that this air conditioner could deliver about two-thirds of its cooling as dehumidification. The test results also validated a computer model, which was used to design an advanced air conditioner for a home that had an SEER of 14.9 and a Sensible Heat Ratio of 0.34. In Phase II, an early-entry market for the liquid-desiccant vapor-compression air conditioner will be identified, in conjunction with a manufacturer of HVAC equipment. A prototype of this air conditioner will be built and tested in a home to: (1) quantify annual energy savings, (2) demonstrate independent control of temperature and humidity, and (3) identify possible control, operating, and maintenance issues that would be addressed in a second prototype. Commercial Applications and Other Benefits as described by awardee: A highly efficient electric air conditioner that provides independent control of temperature and humidity within homes, even under the most humid summer conditions, would address problems of poor indoor air quality, mold and mildew growth, and the waste of energy from over-cooling. The technology also should be applicable to the very large market for commercial rooftop air conditioners.