Study On Indoor Thermal Comfort And Energy Saving Effect With High Air Exchange In Winter Season

Energy consumption of heating rooms will increase when air exchange rate become large. Because the mechanisms of heating methods used currently, such as radiator heating, ceiling heating and warm-air heating, are different from each -other, the indoor thermal environment is not the same when each one of them employed for room heating. For enhancing energy efficiency of heating rooms, indoor thermal comfort and energy saving effects should be investigated when natural ventilation is used to make a good air quality indoors. In order to obtain the suitabilities of different heating methods in industrial and residential buildings, experimental and theoretical studies, and numerical simulations have been carried out in the present paper.The experimental data show that the inner surface temperature distributions of the testing room are affected lightly by ventilation process. The walls of the room heated by ceiling heating have energy storage ability, which makes its energy saving effect superior to conventional radiator heating and warm-air heating. The average PMV value indoor by ceiling heating is higher than the other two be used for room heating under same energy consumption, and the vertical distribution of indoor temperature results by either of the method in a heating room is different from that in a closed room. When air exchange rate is high, The vertical variations of temperatures in the zone of occupant action are similar by the three methods. Thus, the vertical indoor air temperature distribution in the high air exchange room is not mainly determined by heating method, but the way of air current.The experimental results indicate that when the air flow rate is determined, the key problem for energy saving is how to keep the indoor thermal comfort at a suitable level and reduce the difference between the internal and external temperature of the room. A formula is gained for calculating the critical values of air exchange rate. When ventilating rate is greater than the value, radiating heating is the better way for energy saving, or else, convection method in heating is more suitable.Numerical simulations are carried out by analyzing on the experimental data for discussing the indoor temperature field and PMV distribution under different ventilating rate and different heating method. Compared with the common situation, The result of numerical simulation shows that the cold air will result in an uncomfortable area indoors by using either of the method mentioned above. PMV and the indoor temperature field canbe used to evaluate the effect of heating in a large amount air current condition. The result of analysis indicate that the radiation heating and radiator heating have some advantages in such rooms, and hot-air heating is an unsuitable way for room heating.