The objective of this study is to compare annual energy requirements for buildings by using different types of heating, ventilating, and air-conditioning (HVAC) systems for various sizes of office buildings located in different cities. A commercially available energy-analysis computer program has been used to analyze and compare, through simulation, energy efficiencies of three common HVAC systems with the water-loop heat pump (WLHP) system. A building model was developed that used typical internal building loads, operating schedules, building construction materials, windows, and ventilation loads. This model demonstrated that WLHP systems are energy efficient and possess significant potential for heat recovery. Annual HVAC energy requirements increase by 40% if a four-pipe fan coil system is used, by 100% to 200% if a variable-air-volume system is used, and by 300% to 400% if a single-zone reheat system is used rather than the water-loop heat pump system.

KEYWORDS: Energy consumption, heat pumps, buildings, air conditioning, variable volume air conditioning, comparing, heating, ventilation, offices, computer programs, models, heat load, heat recovery, fan coil units.