| Jiangsu province stipulates that all new residential buildings with 12 floors or less,as well as newly built hotels,hotel buildings and other public buildings with hot water demand should be designed and installed with solar hot water system.In this context,the thermal utilization of a commercial vacuum heat pipe solar water heating system in a building in nanjing was studied.According to the civil building solar energy hot water system application technology standard GB50364-2018 ",combining with the nanjing area months solar total radiation quantity,calculate the 1 m~2 vacuum tube collectors,150 l water tank of hot water system in different irradiation 12 months in the year to the heat and hot water needed to add heat,unbalanced relationship in between is found,among them 1 ~ 3?11?12 month need auxiliary heating,from April to October collector will produce more heat,thus found that the actual engineering projects,the auxiliary heat sources and waste heat utilization of solar energy hot water system,It has great practical value and guiding significance.This paper is a commercial building in nanjing area.According to the relevant technical specifications,the design and calculation of solar water heating system are carried out.The equipment such as solar collector,heat storage tank,heat exchange tank,circulating heat pump and expansion tank are selected and the corresponding drawings are drawn.TRNSYS software platform was used to simulate the system dynamically.After setting the parameters such as collector area,tank volume,water recharge and water recharge time in the system,a simulated operation was conducted for 8760 hours throughout the year,and parameters such as solar radiation intensity,water temperature of 8T heat storage tank and water temperature of 2T heat exchange tank were obtained by simulation.The auxiliary electric heater is used as the auxiliary heating source in the simulation to obtain the auxiliary heating and heating time from January to April and October to December.By converting the auxiliary heating into electricity consumption and gas consumption,the monthly and daily electricity consumption,electricity consumption,gas consumption and gas fee are obtained.Through calculation,it is found that using gas boiler as auxiliary heat source can save 30% on average every month.In addition,for June to September when the temperature exceeds 35?,the outlet water temperature of the solar collector is above 80?.The hot water at this temperature can be used as a heat source to drive the lithium bromide absorption chiller to cool the building.In fixed cooling water inlet temperature,chilled water under the condition of import and export parameters such as temperature,solar collector is calculated under the condition of different water temperature,the thermal coefficient of refrigerating machine,combined with simulation of residual heat,according to the refrigerating eight hours a day and 200 w/m~2 building cooling load index,calculated from June to September day average refrigeration power of 46.52 k W,57.01 k W,50.13 k W,40.53 k W,June to September waste heat for 232.61 m~2,285.50 m~2,250.65 m~2 and 202.64 m~2 building cooling.According to the relationship between the area of the collector and the volume of the water tank,a scaled-down hot water system is built and simulated.At 11:00-14:00,the irradiation intensity was relatively high.The collector was irradiated by the sun for 3 hours continuously.Four experiments were conducted.The results show that the temperature rise in the water tank,the system heat collection efficiency and the temperature difference between the inlet and outlet water of the collector are positively correlated with the irradiation value,the water temperature of the water tank is greatly affected by the initial temperature,and there is a delay between the temperature rise of the water tank and the irradiation intensity.The experimental results were compared with the simulation results,and it was found that the temperature rise rate of the direct-flow hot water system was 8.25?/hr,which was 0.97?/hr higher than that of the indirect heating system.Proved at the same time,even in the year of the irradiation intensity is relatively low in 11,12,irradiation intensity is controlled in 800 w/m~2,collector after the continuous sun,tank temperature can reach 85 ?,is even higher,can satisfy the requirement of the absorption chiller heat source temperature,so the irradiation intensity is higher in the summer,solar hot water system of waste heat used for driven absorption refrigerating machine for building cooling more feasible. |
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