ASHRAE - American Society of Heating@ Refrigerating and Air-Conditioning Engineers@ Inc.
Scope
INTRODUCTION Maintaining comfortable indoor air with high Indoor Air Quality (IAQ) is the primary task for HVAC engineers. Ventilating buildings with fresh@ outdoor air is one way to create a pleasant environment for the occupants. Recent researches (Bornehag et al. 2005; Fanger 2006) show the effect of ventilation on improving the health and productivity of office workers. The importance of ventilation can also be seen in the significant increase in the minimum recommended ventilation rates for commercial buildings in ASHRAE Standard 62.1 from1981 to 2004 (ASHRAE 2004). Increasing oil prices and consequently rising energy costs for conditioning buildings has drawn attention to energy recovery technologies to reduce the additional costs imposed by ventilation. Air-to-air energy recovery systems use exhaust air energy to precondition the supply air and can significantly reduce the HVAC life-cycle costs in buildings (Fauchoux et al. 2007 and 2009; Asiedu et al. 2005). Several air-to-air energy recovery devices are currently used to precondition outdoor ventilation air. These systems can be divided into two categories: (1) devices that only recover sensible energy such as plate heat exchangers@ heat pipes and run-around heat exchangers@ and (2) systems with the ability to transfer both heat (i.e. sensible energy) and moisture (i.e. latent energy) between the supply and exhaust air streams. Ideal energy recovery systems are the ones with the ability to recover moisture as well as heat as these systems provide more energy savings and better indoor conditions (Erb et al. 2009; Fauchoux et al. 2007 and 2009).