Economic returns of improving thermal environment and fresh air provision in the tropics

Abstract

This paper reports the outcomes of a cost-benefit analysis based on field studies conducted in the Tropics. The effects of air temperature and outdoor air supply rate on the call handling performance of the call center operators, as the performance metric, were investigated using a 2×2 repeated-measures study over nine weeks. During each intervention week, call handling performance data (i.e. the talk time) was continuously recorded by the automated call distribution system. The main effects of air temperature and ou tdoor air su pply rate on averaged ta lk time of each operator were analyzed using the repeated-measures mixed-effects model analysis. The reduction in talk time was quantified in terms of monetary value. Net-present method was then applied to analyze the overall economical returns. Reducing room air temperature setting to achieve a neutral-to-slightly-cool thermal sensation could improve talk time by 5.7%. The estimated benefit to achieve this optimum condition exceeded the costs by a factor of 18.0. This translates to an annual savings of approximately 170 million USD for the Singapore administration and service sector. Increasing outdoor air supply rate could improve talk time between 5.1 to 8.2% depending on the current operating condition of the ventilation system. Based on data taken from an office, the estimated benefit could potentially exceed the costs by a factor of 55.0, which is equivalent to an annual saving of approximately 240 million USD for the Singapore administration and service sector. The basis of these estimates, derived from energy simulations, cost data of equipment and employment statistics, are detailed in the paper. These findings reiterate the enormous potential for productivity gain arising from improving thermal condition and providing better air quality. © 2008 ASHRAE.