MAXIMIZINGTHE VENTILATION RATE FOR COOLING ENERGY REDUCTION

摘要

It is widely recognized that to minimize the ventilation rate will reduce the energy consumption of air conditioning systems in both heating and cooling seasons. However, the temperature difference between indoor and outdoor air temperatures in the cooling season is not so large in comparison with that in the heating season. In addition, there are many hours when the outdoor air temperature in the cooling season is lower than the design space air temperature. Therefore, to minimize the ventilation rate may not be important for energy reduction in cooling with air conditioning systems. Better indoor air quality may be provided without increasing the energy requirements by increasing the ventilation rate during the cooling operation. Energy reduction in air conditioning system operation can be also expected depending on the temperature and humidity conditions required in the cooling season. Appropriate ventilation rates and a basic control strategy are discussed using simulation results of a typical office building with the climatic conditions of Japan where the space cooling consumes larger amount of energy than the space heating in most major cities. The simulation results of the model office building in Tokyo show that the energy requirements for the cooling are almost the same wheather the ventilation rate is set to a minimum outdoor air requirement or to a maximum ventilation rate for all outdoor air without mixing with the return air from conditioned space. This simulation results show the potential of the outdoor air as a cooling source in the cooling season. Control strategies of the ventilation rate in practical design and operation of the air conditioning systems are discussed using the energy requirements obtained by the system simulation.