Investigating The Relationship Between Mean Radiant Temperature (MRT) And Predicted Mean Vote (PMV) : A case study in a University building

Abstract: Thermal comfort in an indoor environment is largely dependent on the four environmental and two personal parameters which is most commonly measured by the Predicted Mean Vote (PMV) model developed by Fanger. It has been studied that variations in these parameters beyond a range could lead to discomfort complaints. However, little research has been done on the effect of mean radiant temperature variations and its influence on predicted mean vote and thermal comfort specially in an actual building environment. This study aims to investigate the relationship between mean radiant temperature and predicted mean vote in indoor environment. Using the methods of on-site measurement of indoor environmental parameters and subjective votes on thermal sensation in an educational building; it was found that rise in mean radiant temperature lead to rise in PMV value and discomfort vote amongst occupants seated near glazed façade. A very strong positive correlation was found between mean radiant temperature and PMV near the window side of the room under warm and sunny weather conditions. Analysis of indoor environmental data from the several measurement sessions concluded that rise in mean radiant temperature and PMV was not noticed until there was a direct solar transmission through the window. It is advisable to use solar shading on windows, but special consideration should be given to the trade-offs between energy consumption (heating or cooling) and lighting energy consumption. No conclusions could be made in terms of ankle draft discomfort due to experimental limitations and more research would be required to investigate this phenomenon.