Numerical Simulation And Optimization Of Energy Saving Application Of Civil Fresh Air System

Good indoor environment is benefit to people for feeling,work efficiency and health.Besides diluting pollution and increasing oxygen content of indoor air,saving building energy is achieved by the fresh air system(FAS)with heat recovery from indoor air.Suitable position of the FAS is also help for good indoor environment,and saving energy,and pollution emission reduction.In this paper,the heat transfer process of a single brand fresh air system was studied by numerical simulation.Through the obtained cloud maps at different velocity,the effects of velocity changes on fluid flow state,heat transfer effect and pressure drop in the heat exchanger were analyzed.According to the problems existing in the heat transfer process of the original model,the internal structure of the heat exchanger was improved,and two new heat exchanger models were obtained.The cloud maps of the three models at different flow rates were compared,and the flow field in the improved structure was found to be better.At the same time,the effects of different channel heights and flow rates on the Nu,?p and f of the three structural heat exchangers were studied.Based on the Nu,?p and f obtained from the original model,The equal heat transfer performance of the heat exchanger was analyzed by the equal pumping force constraint evaluation method.Finally,the parameters corresponding to the best heat transfer performance and the minimum pressure drop were obtained.Simplify the indoor model and establish a corresponding numerical calculation model.Combined with the heating conditions of the floor heating,the indoor temperature field and velocity field of the fresh air system in different installation positions(condition 1,working condition 2)and different flow rates are analyzed to meet the requirements of indoor comfort.The influence of the flow field change on the temperature field is analyzed,and the reason why the heat exchange between the airflow and the floor heating surface is poor is obtained,and the suitable installation position is determined.Figure 40;Table 7;Reference 60.