A Review of Ventilation and Air-Conditioning Technologies for Energy-Efficient Healthy Buildings in the Tropics

摘要

Clear associations are being established between ventilation rates, indoor air quality (IAQ), and the productivity of the workforce in various types of buildings, most significant of which is the commercial and office building sector. While source control is commonly advocated as the fundamental approach to eliminating or containing the contaminant levels inside the building, a more practical and often necessary approach is likely to be exposure control. Thus, ventilation plays an important role in providing a good quality built environment. However, climatic conditions pose considerable challenges in the design of air-conditioning systems, and, in a hot and humid climate, this can translate to significant energy penalty. Two considerations are highlighted in order to achieve "good" IAQ and energy efficiency—the enhanced dehumidi-fying performance of cooling coils and the effectiveness of air distribution strategies. This paper reviews some of the current and future technologies for air conditioning and air distribution that can collectively con tribute to the design of energy-efficient healthy buildings. The air-conditioning technologies reviewed include outside air pretreatment systems, single-coil twin-fan (SCTF) systems employing a compartmented cooling coil, desiccant dehumidification systems, and heat pipes. The air distribution systems reviewed include an SCTF system with independent "ventilation" and "thermal cooling" on zone-based demand, a personalized ventilation system coupled with secondary ambient air distribution system, a displacement ventilation system, an underfloor air distribution system, and a dedicated outdoor air system coupled with radiant chilled ceiling. Applications of some of these technologies, such as the SCTF air-conditioning and air distribution systems and personalized ventilation systems, in Singapore are presented.