The Overcooling Hong Kong: Social and Technical Solutions for Sustaintable Development

Dr. Shiming Deng
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Hong Kong is located in the subtropical region, featured by high temperature and humidity from April to October in a year. Air conditioning has therefore become necessary in various buildings to maintain a suitable indoor environment for people to live and work, consuming approximately one third of the total energy use in Hong Kong. Recently, the extensive media coverage of space overcooling in Hong Kong has attracted significant public attention. It was reported that low indoor air temperatures of as low as 16 ºC were found in many buildings and public transports, “giving Hong Kong some of the coldest air conditioning in the world” and “members of public have shivered through artificial chills” (SCMP, 27 June 2005). On the other hand, the government of Hong Kong SAR has advocated setting indoor air temperature at 25.5 ºC since October 2004, which has clearly not yet followed by many and further promotional / educational activities are necessary.

Cooling a space to an unnecessary low air temperature wastes energy, which is converted from natural resources, thus against the spirit of sustainable development. Having said this, space overcooling in Hong Kong is in fact a complicated issues stemming from both social and technical causes. Socially for example, the perception of general public on air conditioning is to provide cold air. In business sector, formal dressing code of wearing business suit with tie throughout a year demands a lower indoor air temperature in summer. Technically, to many, it is perhaps a straight-forward simple move to set a thermostat in a space to 25.5 ºC. Nonetheless, whether this 25.5 ºC can actually be maintained is already problematic in many conditioned spaces with its existing air conditioning installations. Even when and where this 25.5 ºC is actually maintained, whether a conditioned space is acceptable in terms of thermal comfort is still in question, as thermal comfort is actually affected by other indoor air parameters such as air humidity, velocity, clothing value, metabolic rate etc, in addition to air temperature. The commonly-seen over-sizing of central air conditioning plants and the coupled cooling and dehumidification air handling process in air conditioning systems all contribute to the problem of space overcooling.

Therefore, for sustainable development, it is essential that the problem of space overcooling should be addressed from both social and technical points of view, with an ultimate goal of reducing waste of limited natural resources while preserving the quality of life which is currently enjoyed by people in Hong Kong. It is therefore proposed to eliminate or at least minimize the problem of overcooling space in Hong Kong, through programmed work of surveying, experimentation, demonstration and education, in search for solution socially and technically.

Keywords: Space Cooling, Energy Use, Overcooling, Hong Kong
Stream: Environmental Sustainability
Presentation Type: Paper Presentation in English
Paper: A paper has not yet been submitted.

Dr. Shiming Deng

Associate Professor, Building Services ENgineering Department, The Hong Kong Polytechnic University
Hong Kong

Ref: S06P0273