Six boxes designed to measure the mass-transfer coefficient were made, and a variety of construction materials with and without photocatalyst coating on the surface was tested. The test results show that building materials with photocatalyst coating had evaporation effects, and that the surface temperature of the experimental boxes was lower by about ten degrees centigrade and the inside temperature by about seven degrees centigrade on the average when boxes were watered than when they were not watered. It was discovered that water spraying was also effective in reducing the temperature of boxes without photocatalyst coating. The pragmatic standard mass-transfer coefficient in absolute humidity was calculated by testing various construction materials for an extended period of time. Based on the coefficient and dynamic thermal load calculation program, LESCOM-vapor, a simulation on the test boxes and building for experimental use was conducted, and figures obtained from the simulation were found to be similar to actual figures. The LESCOM-vapor program makes it possible to estimate what impact water spraying will have on the thermal environment of buildings.
