Evaporative condensers: The next generation in residential air conditioning?
Residential air conditioning is a load that many utilities love to hate since it often represents a low load factor as well as a small source of total utility revenue. Performance of typical air-cooled condensing units degrades significantly as outdoor temperatures rise, resulting in higher demand per unit of cooling delivered. Two evaporative condenser (EC) technologies offer the potential for significant performance improvements, particularly in hot, dry climates. The first technology, ECI, is an evaporative pre-cooler which significantly reduces condenser inlet air temperatures. A second generation product, EC2, offers greater efficiency improvements by immersing the condenser coil in an evaporatively cooled sump. In dry southwestern climates, the EC2 can offer a 20-35 F condensing temperature advantage over conventional equipment which translates to increased capacity, efficiency, and reduced demand. This paper evaluates EC cooling performance from three perspectives: (1) laboratory testing of both EC technologies versus 10 and 12 SEER air conditioning, (2) EC2 field monitoring, and (3) DOE-2.2 performance projections. Lab testing demonstrated that EC technologies consistently outperform air-cooled condensing units. At 110 F condenser inlet temperature, an EER advantage of 36% and 105% versus SEER 10 was determined for EC1 and EC2, respectively. DOE-2.2 simulations based on laboratory testing and manufacturer's data were performed using San Jose, Sacramento, and Fresno weather data. Results indicate that under typical cooling use assumptions and current technology costs, both EC technologies are cost-effective in Fresno, but not in San Jose or Sacramento. This is not discouraging given that (1) EC costs will come down with increased production, (2) high-use customers will have more favorable economics, and (3) California builders value technologies which offer energy compliance credits. Extrapolating DO-2.2 performance projections to the potential 120,000 annual new and retrofit EC sites in Northern California results in projected annual energy and demand savings of 86.3 GWH and 167 MW{gt}
- Research Organization:
- Davis Energy Group, Davis, CA (US)
- OSTI ID:
- 20001982
- Report Number(s):
- CONF-980815-; TRN: IM0001%%419
- Resource Relation:
- Conference: 1998 ACEEE Summer Study on Energy Efficiency in Buildings, Pacific Grove, CA (US), 08/23/1998--08/28/1998; Other Information: 10 volume set available for $200.00; PBD: 1998; Related Information: In: 1998 ACEEE summer study on energy efficiency in buildings: Proceedings, [3100] pages.
- Country of Publication:
- United States
- Language:
- English
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