Research Of The Influence Of Condensing Heat Release To The Environment And Natural Ventilation

The energy reserves in the country and energy consumption situation of building heating and cooling systems have been reviewed at the beginning. The energy consumption of air-conditioners take a huge proportion in the energy consumption of whole buildings, and the demand for air-conditioners will increase rapidly in future. Heat energy released from the condensing units can increase the environment temperature around the buildings and even induce the"urban heat island effect". The condensing heat drained into the air not only increase the building cooling load, but also degrades the efficiency of the air-conditioners and may even interrupts the operation of the air-conditioners, wastes a lot of energy.For its simplicity, convenience and flexibility, the spilt-type air-conditioner is widely used in residential buildings. The split-type air-conditioner is composed of two parts: indoor unit and outdoor unit. A numerical analysis of the airflow and heat dissipation at the outdoor unit is presented using the commercial CFD software Fluent. Thus the paper gives introduction about the CFD basic theory and common commercial CFD software.The temperature distribution and air flow around the outdoor unit is simulated by using Fluent at different wind speed and different heat release rate for research the temperature and flow field around the condenser and analyze the effect of outdoor unit heat release on thermal environment around the building. From simulation results it's found out that the hot air flow upwards and gradually attached to the wall because of thermal buoyancy. The plume configuration has relation to the heat release efficiency of the condenser as well as the wind speed of environment. A large range is affected by the hot air drained from the outdoor unit. The concept of heat pollution boundary layer is first presented to evaluate the range of heat air drained from the condenser. The findings of this paper give several rationalization proposals to the placement of outdoor units. The outdoor unit should be placed in open to ensure airflow free, thus the installed distance of outdoor units should be enlarged to avoid reduce operating efficiency because of the interaction of heat released from the units.The thermal environment around buildings is changed by the heat released from outdoor units and the natural ventilation is effected as well. The outdoor unit is placed on different position to simulate the different air flow process. The flow speed,temperature and pressure distribution are analyzed during different ventilation processes, and finally the effect of the condensing heat release on the natural ventilation is researched. The findings of this paper give good references to the placement of split-type air-conditioners in future residence projects.