| Solar energy has always been used as clean energy,the conversion of solar energy to heat and the use of air for indoor heating has been the important issue of energy conservation.Therefore,it is of great significance to study how to improve the efficiency of solar air collector and how to use heat storage device to store excess heat for indoor heating at night.In this paper,a numerical heat transfer model for a new type of solar air collector is established by using CFD simulation software.The new collector includes fresh air and indoor return air with a flow ratio of 1:9,through using two air collectors,the simulation results show that under the inlet velocity of fresh air is 0.27m/s,the inlet velocity of upper and lower runners is 1.35 and 1.08m/s respectively,and the inlet temperature of fresh air and return air is 276 and 291 K respectively,the heat gain is 704.26 W,fresh air outlet temperature is 313.33 K,upper and lower return air outlet temperature is 330.95,345.15 K,the collector efficiency is 56.06%.The numerical heat transfer models for different paraffin heat storage bodies are established respectively,and calculated by FLUENT software.Under the premise of 6 hours of heat storage simulation calculation and 4 hours of heat release simulation calculation,the results show that the melting degree of paraffin wax is92.06% in the wax regenerator with the fin thickness is 15 mm,which is higher than that in the regenerator with fin thickness is 10 mm,and the exothermic rate is slower than that in the regenerator with fin thickness is 10 mm.The paraffin regenerator with 25 mm fin spacing has higher melting degree and average temperature of paraffin than the other three regenerators.The paraffin melting degree of 16 paraffin regenerators with air ducts is 92.42% and the paraffin average temperature is 319.64 K,which is higher than the other three regenerators.The heat release rate is slower.The paraffin regenerator with 25 mm fin spacing has higher paraffin melting degree and average paraffin temperature than the other three regenerators.The paraffin melting degree of 16 paraffin regenerators with air ducts is 92.42% and the paraffin average temperature is 319.64 K.The results show the air outlet temperature in the first hour is 316.10 K,the air outlet temperature in the fourth hour is 314.82 K,and the air outlet temperature in the eighth hour is 299.88 K.The indoor heating period is divided into two stages: day and night,and the night heating period is divided into two different periods through using Airpak software.The results show the indoor minimum temperature is maintained at 20.7℃ when the fresh air inlet velocity is 0.06m/s and the return air inlet velocity is 0.18m/s during the daytime heating period,while the indoor minimum temperature is19.6 ℃in the first stage of night heating,the indoor temperature gradually decreases every hour during the second stage of night heating,and the lowest temperature is 17.6℃ which basically meets the requirements.Requirements for indoor heating standards. |
