Thermal comfort and energy consumption of the radiant ceiling panel system. Comparison with the conventional all-air system

The purpose of this study is to investigate the various characteristics of a radiant ceiling panel system and their practical application to office bu ildings. The radiant ceiling panel system and conventional air-conditioning system were compared in terms of thermal comfort, energy consumption, and cost. Thermal environment, along with human response, was tested by using a small meeting room equipped with radiant ceiling panels. The responses wer e collected by questionnaires given to the male subjects in the room. The e xperiment for the female subjects was conducted separately. Results show th at the radiant ceiling panel system is capable of creating smaller vertical variation of air temperature and a more comfortable environment than conve ntional systems. When using a cooled ceiling, a small volume of supplied ai r creates a less draught environment, which reduced the discomfort of feeli ng cold in the lower part of the body. Numerical simulation of yearly energ y consumption and cost estimation were conducted. Typical office rooms loca ted on the 3rd, 4th, and 5th floor of a six-floor building in the Tokyo are a were simulated. Since part of the sensible heat load is handled by radian t ceiling panels, the volume of supplied air can be reduced, leading to low er energy consumption for air transport. By using the radiant ceiling panel system in one of the three floors of the simulated building, energy consum ption can be reduced by 10%. Estimated pay back time was from 1 to 17 years depending on the market price of the radiant ceiling panel. (C) 1999 Elsev ier Science S.A. All rights reserved.