Studying the Thermal and Cryogenic Performance of Shevadun in Native (Local) Buildings of Dezful Based on Modeling and Environmental Measuring

Abstract

In the native buildings of Dezful, spaces called (Shevadun) that were constructed under the ground, were used, which used the thermal mass property of the earth to be protected from cold and warm weather conditions. In the old buildings of Dezful, these spaces that are constructed under the ground are called ((Shevadun)) in native language. In this research, first,the temperature and humidity in one Shevadun sample of the Dezful native buildings were measured using Data Logger units in 5 days (during August). Then, using the Design builder software which is a reliable software in modeling the energy and CFD calculations, the available sample is simulated in order to study the thermal and cryogenic performance. The results of the research show that the temperature of Shevaduns in summer is less than the average maximum temperature and the average minimum temperature of outdoor, and the thermal condition of the Shevadun space during the measurement is lower than the thermal comfort limit which is specified in the ashrae standard. In other words, the Shevadun space is colder than the summer comfort limit of ashrae. The effect of the cold weather of Shevadun on summer places above it which are connected with a trap door, was studied, and the results show that if the summer habit is connected with shevadun, the average temperature is 4 degrees centigrade lower than when the connection trap door is closed, and when the trap door is open, the relative humidity of the summer place will be 2 to 3 percent’s higher, which shows the high potential of the shevaduns in using the passive cooling of spaces. The other part of the paper studies how the cool air inside the shevadun is transferred to the summer place by the trap doors. The results show that in the day, because the door of the shevadun is closed to prevent from entering the warm air of outside to inside the shevadun, the air movement in shevadun and trap door which is the connecting canal between the shevadun and summer place, is very slight, and it is the result of the temperature difference between the vertical layers of the air inside the shevadun , trap door and space, so that , this air movement is not felt, and the cool air of the shevadun has less effect than during the night that the door of shevadun is opened for ventilating its air.