小型太阳能驱动单效溴化锂吸收式制冷机组的模拟研究

SIMULATION STUDY OF SMALL SOLAR DRIVING SINGLE-EFFECT LITHIUM BROMIDE ABSORPTION REFRIGERATION UNIT

对太阳能驱动的单效溴化锂吸收式制冷机组的性能进行数值模拟研究,通过TRNSYS建立太阳集热器仿真系统,分析太阳能辐射强度及太阳能驱动温度对机组制冷性能的影响;利用EES(engineering equation solver)编程建立小型单效溴化锂吸收式制冷机组(12 kW)模型,采用动态数值模拟的方法,研究小型制冷机在设计工况以及变工况下的热力性能和机组运行状态。并采用耦合研究的方式,系统分析驱动热源温度、热源流量、冷媒水进出口温度、冷却水进口温度等因素对机组制冷性能的影响。研究结果表明:低温集热器的工作温度区间和单效溴化锂制冷机匹配性较好,既可避免能源品位的浪费,又不会使热源驱动温度过高,造成溴化锂溶液结晶的出现。太阳有效辐射强度对机组制冷性能影响显著,辐射强度从550 W/m^2增至990 W/m^2时,制冷量由5 kW增至16 kW,在设计参数下,小型太阳能吸收式制冷机的性能系数可达到0.70。

Performance of solar-energy single-effect lithium bromide absorption refrigeration unit is numerically simulated.The solar collector simulation system is established by TRNSYS. The effects of solar radiation intensity and solar driving temperature on the refrigeration performance of the unit are analyzed. The EES programming is used to establish a small single-effect lithium bromide absorption refrigeration unit(12 kW)model. The dynamic numerical simulation is used to study the thermal performance and unit operating state under design conditions and variable operating conditions. The coupling research method is used to analyze the effects of driving heat source temperature,heat source flow,inlet and outlet temperature of refrigerant water,cooling water inlet temperature and other factors on the refrigeration performance of the unit. The research results show that the operating temperature range of the low temperature collector is better matched with the single-effect lithium bromide refrigerator,which not only avoids the waste of energy grade,but also avoids causing the driving heat source temperature too high,resulting in the crystallization of lithium bromide solution. The effective solar radiation intensity has a significant impact on the refrigeration performance of the unit. When the radiation intensity increases from 550 W/m^2 to 990 W/m^2,the cooling capacity increases from 5.0 kW to 16 kW. According to the design parameters,the coefficient of performance of the small solar absorption chiller can reach 0.70.