IEQ in Offices

IEQ of air-conditioned offices of Hong Kong

IEQ model

For benchmarking purposes, we have developed an IEQ model. It is noted that some parameters have been further improved in our later studies.

Benchmarks

Indoor environmental quality (IEQ) of air-conditioned offices could be benchmarked by the occupants’ acceptability. We proposed a five-star IEQ benchmarking system based on an expression of the occupants’ overall IEQ acceptance on thermal comfort, indoor air quality and aural and visual comfort. By using the proposed IEQ index, the occupants’ adaptive response of clothing adjustment for the perceived thermal environment was reported in order to determine the overall IEQ acceptance. The benchmarking parameter of a star rating system and the IEQ index were applied to express relative IEQ performance of air-conditioned offices in Hong Kong. The IEQ performance of some recommended environmentally sustainable policies for ‘Excellent’ and ‘Good’ offices was evaluated and compared with the existing offices. The probable IEQ in offices of Hong Kong were determined by the Monte-Carlo simulations from surveyed studies reported. The proposed star rating system would serve as a quantitative measure of IEQ for air-conditioned office environment in Hong Kong and given selected model parameters, it would be a useful reference for similar environment where the evaluation of an occupant is expected.

Example benchmarking values and star-ratings of IEQ of Hong Kong air-conditioned offices (Indoor and Built Environment 18:123-129, 2009).

Related topics: Some benckmarking applications

Thermal energy consumption

Maintaining an acceptable indoor environmental quality (IEQ) for air-conditioned office buildings consumes a considerable amount of thermal energy. We evaluated thermal energy consumption with the overall occupant acceptance of IEQ in some air-conditioned offices. An empirical expression of an IEQ index associated with thermal comfort, indoor air quality, aural and visual comfort is used to benchmark the offices. Employing input parameters obtained from the building stocks of Hong Kong, the office portfolios regarding the thermal energy consumption and the IEQ index are determined by Monte Carlo simulations. In particular, an energy-to-acceptance ratio and an energy-to-IEQ improvement ratio are proposed to measure the performance of energy consumption for the IEQ in the air-conditioned offices. The ratios give the thermal energy consumption corresponding to a desirable percentage of IEQ acceptances and to an IEQ upgrade respectively. The results showed a non-linear increasing trend of annual thermal energy consumption for IEQ improvement at the offices of higher IEQ benchmarks. The thermal energy consumption for visual comfort and indoor air quality would also be significant in these offices.

Further information:

Mui KW, Wong LT, 2007. Neutral temperature in subtropical climates - a field survey in air-conditioned offices, Building and Environment 42(2) 699-706.

Mui KW, Wong LT, 2007. Evaluation of neutral criterion of indoor air quality for air-conditioned offices in subtropical climates, Building Services Engineering Research and Technology 28(1) 23-33.

Mui KW, Wong LT, 2006. A method of assessing the acceptability of noise levels in air-conditioned offices, Building Services Engineering Research and Technology 27(3) 249-254.

Mui KW, Wong LT, Hui PS, 2009. Indoor environmental quality benchmarks for air-conditioned offices in subtropics, Indoor and Built Environment 18(2) 123-129.

Wong LT, Mui KW, 2009. An energy performance assessment for indoor environmental quality (IEQ) acceptance in air-conditioned offices, Energy Conversion and Management 50(5) 1362-1367.

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A hand-on calculator of acceptance for indoor environmental quality (IEQ) of air-conditioned offices of Hong Kong