Investigation of the effectiveness of a light pipe in reducing temperature inside the occupied space in Malaysian climate / Mohd Afzan Abdul Halim

Increasing the use of natural daylight for lighting purposes in the buildings may offer savings in total building energy consumption. One technique of utilize the natural light is the use of light pipes that cannot only bring light into otherwise inaccessible or dimly lit places, but also improves the internal environment and visual comfort. This study aims to investigate the effectiveness of light pipe in reducing the temperature in an occupied space for Malaysian climate. The performance of light pipe was evaluated measuring the temperature and relative humidity for both indoor and outdoor simultaneously. The study was divided to four parts. In the first part, the experiment was conducted to measure the temperature and humidity inside the occupied space due to the transmitted daylight from light pipe alone. In the second part, the same measurements were carried out with the room was totally lighted by artificial light. Then the measurements were repeated for the measurement if temperature and humidity due to the daylight that enter through the openings (windows) and also the light pipe. In the final part, the room was lighted up only by daylight through openings. In all four cases, the air temperature and relative humidity for outdoor and indoor were measured simultaneously. Temperature differences and humidity differences between the outdoor and indoor were calculated and comparisons between cases were made. In general it was found that the day lighting transmitted via light pipe gives positive effect in reducing internal temperature and humidity inside the building. The results indicate that the day lighting from light pipe generates less heat compared to artificial lighting as could be observed from the higher indoor and outdoor temperature difference as measured in the first part of experiment. The internal relative humidity was also found to be relatively lower when the room was lighted by day lighting using light pipe compared to artificial light.