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A field study was conducted to evaluate the performance and cost-effectiveness of using an enthalpy recovery ventilator in combination with a conventional packaged air conditioner (AC) to meet the increased ventilation requirements of ANSI/ASHRAE Standard 62-1989 in Florida schools (Shirey et al. 1997). Two portable classrooms located in east central Florida were selected for testing.
With the packaged air conditioner alone, indoor humidity levels frequently exceeded 60% relative humidity (RH), even with outdoor ventilation at only 5 cfm (2.4 L/s) per person according to ASHRAE Standard 62-1981. The high humidity was caused by the single-speed compressor cycling on and off to maintain the indoor temperature while the supply fan operated continuously to provide ventilation air. Indoor humidity levels remained basically unchanged when an enthalpy recovery ventilator was installed and the outdoor ventilation rate was increased threefold in accordance with Standard 62-1989.
Energy recovery by the ventilator was partially offset by the added fan energy required for the intake and exhaust airflows. For example, cooling season tests indicated that the outdoor temperature must exceed the indoor temperature by at least 5°F (2.8°C) to offset the fan power and associated sensible cooling load attributed to the enthalpy ventilator. Due to the added fan energy and the temperate climate of Florida’s east coast, the primary benefits provided by the enthalpy recovery ventilator were reduced capacity requirements and lower peak demand compared to a conventional air-conditioning system with the same ventilation rate (15 cfm or 7.1 L/s per person). An economic analysis indicated a simple payback period of around six years for this specific application, climate, and local energy costs.
Authors: Don B. Shirey, III
Citation: IAQ and Energy 98 Using ASHRAE Standards 62 and 90.1 Conference Papers
Keywords: October, Louisiana, 1998
Citation: IAQ Conference: IAQ 98
Product Details
- Published:
- 1998
- File Size:
- 1 file , 350 KB
- Product Code(s):
- D-8128
