Performance Research Of Solar Fresh Air System

At present,the domestic fresh air system is developing rapidly,but the penetration rate in small buildings such as offices and houses is far from enough.Existing fresh air ventilation equipment is usually large in size,and the amount of fresh air ventilation is relatively large,which is not suitable for promotion in small buildings such as houses.Aiming at this problem,this paper designs a new type of solar fresh air system,which uses solar energy absorbing panels to heat fresh air,and the photovoltaie panel driven fan sends the high temperature fresh air into the room in an organized manner.The system can be used for Ventilation in winter,auxiliary heating and dehumidification in special buildings.Theoretical and experimental research was carried out for this fresh air system.First,the performance of the solar fresh air system designed in this paper was tested,and there were no other auxiliary heat sources during the test.The experimental contents include:testing the dynamic performance of the outdoor unit,comparing and analyzing the performance of the unit at 60°and 880;and testing the indoor thermal environment of the model room to study the changes of the indoor thermal environment under this system;The application example of the indoor temperature change of the residential building is tested to analyze the effect of the actual application of the system.Secondly,the model room is subjected to numerical simulation calculation under stable air supply conditions.Due to the high degree of instability of the system,it is assumed that the system provides stable air supply to the model room.Three working conditions are set according to the air volume.The model is established by Airpak3.0 software,and the solar fresh air system is analyzed under stable air supply conditions,the distribution of indoor thermal environment,and based on the results of this simulation ealculation proposed system improvement measures.Finally,the other properties of the solar fresh air system designed in this paper are studied,and the feasibility of this system for dehumidification of special buildings is discussed.The experimental results show that the heat transfer efficiency of the unit is relatively high under the two installation inclination angles,and the average daily heat collection efficiency is about 60%.Under the air supply condition of the model unit,the daily average fresh air load can be provided by the unit heat collection area.430W;conpared with the test inclination angle of 880,the heat conversion efficiency of the unit is higher under the 60 inclination angle.After the unit is running stably,the efficiency range is basically within the range of 65%±10%.When the solar radiation is strong in winter,the solar heat absorbing plate per unit area can send the outdoor fresh air to the room above 40℃,and the system has a certain filtering effect on the outdoor PM2.5.After the system is operated,the indoor PM2.5 concentration continuously decreases.The PM2.5 concentration during the test was at least 0.055 mg/m3.After the solar fresh air system is stably operated,the indoor temperature can be raised to 16℃ to 18℃.The simulation results show that the larger the fresh air volume,the higher the indoor temperature,the lower the dissatisfaction rate and the better the indoor air quality.However,the amount of fresh air is too large,and the air flow rate around the human body exceeds 0.3 m/s.Especially in winter,the human body will feel the feeling of blowing.If the comfort of the system is higher,the air supply parameters of the solar fresh air system should be controlled.Through the theoretical analysis and calculation of the winter dehumidification performance of the solar fresh air system,the results show that the average daily dehumidification of the unit heat collection area is about 0.6 g/s.The theoretical analysis is carried out in the underground parking lot of the project.The results show that the investment cost of using this system to improve the thermal environment of underground space is small and the effect is considerable.It can be further studied and verified in engineering examples.