Evaluating the Performance and Economics of Transpired Solar Collectors for Commercial Applications
Using transpired solar collectors to preheat ventilation air has recently become recognized as an economic alternative for integrating renewable energy into commercial buildings in heating climates. The collectors have relatively low installed costs and operate on simple principles. Theory and performance testing have shown that solar collection efficiency can exceed 70% of incident solar. However, implementation and current absorber designs have adversely affected the efficiency and associated economics from this initial analysis. The National Renewable Energy Laboratory (NREL) has actively studied this technology and monitored performance at several installations. A calibrated model that uses typical meteorological weather data to determine absorber plate efficiency resulted from this work. With this model, an economic analysis across heating climates was done to show the effects of collector size, tilt, azimuth, and absorptivity. The analysis relates the internal rate of return of a system based on the cost of the installed absorber area. In general, colder and higher latitude climates return a higher rate of return because the heating season extends into months with good solar resource. Wal-Mart has installed approximately 8,000 ft{sup 2} of absorber at its experimental store in Aurora, Colorado. The delivered energy efficiency was measured at 8-11% during January and February 2007. The low collection efficiency is largely due to the oversized absorber and to the multizone control strategy that limits the amount of air pulled through the collector. Analysis shows that more than 50% of the incident solar energy could be delivered with proper control strategy changes.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1022390
- Resource Relation:
- Conference: Scaling Up: Building Tomorrow's Solutions. Proceedings from the 2008 ACEEE Summer Study on Energy Efficiency in Buildings, [17-22 August 2008, Pacific Grove, California](CD-ROM); Related Information: For preprint version see NREL/CP-550-43305
- Country of Publication:
- United States
- Language:
- English
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