Packaged rooftop air conditioners: A buyer`s guide for 5.4 to 20 ton units
Packaged rooftop air conditioners cool the majority of US commercial floor space and contribute significantly to utility peak load. While the efficiencies of most units sold today are clustered just above the voluntary US standards, a number of models don`t meet the guidelines and some new units do considerably better. Many of today`s models are substantially more efficient than those sold a decade ago (EER 10 versus EER 6), so programs targeted at replacing older machines will yield especially cost-effective energy and peak savings. Few resources exist to help potential buyers select among the many models available on the market. This report catalogs the features of 56 packaged rooftop cooling systems in the 5.4 to 20 ton size range, including the most efficient units available. In addition to EER, the authors examine part-load efficiency, compressor unloading strategies, coil and filter face velocity, internal layout, cabinet construction and color, list price, and life cycle cost. The research indicates no correlation between price and efficiency among off-the-shelf products, so the most efficient models may not cost more than the least efficient ones. Custom and semi-custom units are typically more efficient than off-the-shelf models, but generally cost twice as much. Discussions are underway to establish coordinated national efficiency targets for rooftop units, upon which utilities could base incentive programs. Such a market-pull strategy could raise the efficiency of mass-produced rooftop units to levels available now only in custom and semi-custom models.
- OSTI ID:
- 55508
- Resource Relation:
- Other Information: DN: Publication No. TU-93-1; PBD: 1993
- Country of Publication:
- United States
- Language:
- English
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