High outdoor ventilation air requirements can lead to significant increases in building energy use, thermal discomfort, indoor air quality problems, and litigation. Engineers often avoid ground-source heat pumps because of the perception that there are no acceptable methods for conditioning the ventilation air. However, this difficulty is currently a problem with all types of heating and cooling systems. Decisions may be based on system performance at design conditions without regard to seasonal energy consumption. The bin temperature method was used to evaluate the energy use of outdoor air treatment systems. Bin weather data (ASHRAE 1995) is presented in a format that can incorporate psychro-metric analysis of cooling and heating coils and energy (or heat) recovery equipment. The method was used to compare five equipment options for a four-story office building in Birmingham, AL with a 40 hour per week occupancy. The lowest seasonal energy consumption was found to be an air-to- air heat recovery heat pump followed by a conventional DX cooling/furnace, a heat recovery wheel, a water-to-water heat pump, and a plate heat exchanger heat recovery unit. An economizer, "free cooling" mode proved to be a valuable option.

Units: Dual