Apte, M.G., Delp, W.W., Diamond, R.C., Hodgson, A.T., Kumar, S. Rainer, L.I., Shendell, D.G. Sullivan, D.P. and Fisk, W.J. Report on HVAC Option Selections for a Relocatable Classroom Energy and Indoor Environmental Quality Field Study. October 2001. 19 p.
It is commonly assumed that efforts to simultaneously develop energy efficient building technologies and to improve indoor environmental quality (IEQ) are unfeasible. The primary reason for this is that IEQ improvements often require additional ventilation that is costly from an energy standpoint. It is currently thought that the health and productivity in work and learning environments requires adequate, if not superior, IEQ. Despite common assumptions, opportunities do exist to design building systems that provide improvements in both energy efficiency and IEQ. This report outlines the selection of a heating, ventilation and air conditioning (HVAC) system to be used in demonstrating such an opportunity in a field study using relocatable school classrooms. Standard classrooms use a common wall mounted heat pump HVAC system. After reviewing alternative systems, a wall-mounted indirect/direct evaporative cooling system with an integral hydronic gas heater is selected. The anticipated advantages of this system include continuous ventilation of 100% outside air at or above minimum standards, projected cooling reductions of about 70%, inexpensive gas heating, improved airborne particle filtration, and reduced peak load electricity use. Potential disadvantages include restricted climate regions and possible increases in indoor relative humidity levels under some conditions.