A novel solar assisted heat pump (SAHP) system for in-bin grain drying was proposed to solve the problems of poor uniformity and long drying time of grain in depot with higher initial water content in high grain piles. The effects of different operational parameters on the drying performance were numerically and experimentally investigated. The experimental results indicated that the thermal efficiency of the solar collector and the COP of the heat pump reached 63% and 5.03 under given conditions. The average heating capacity of the SAHP system was 130.2 kW, consistent with the simulation results under a typical sunny day in winter. The average water content of 3,760 tons of grain dropped from 12.9% to 12.5% after 42 h of drying. The specific moisture extraction rate of the proposed system and the exergy efficiency of the grain bin were 1.934 kg/kWh and 40.27%, respectively. The operating cost of SAHP grain drying decreased from 5.57 $/t to 1.43 $/t compared with the grain drying machine for the same drying weight. The daily drying capacity increased from 166 t/d to 334 t/d compared with the mechanical ventilation drying for the same water content reduction rate. This investigation provided guidance for expanding future researches on the SAHP system applied for in-bin grain drying.

【摘要】：针对高位粮堆中初始含水量较高的库区粮食干燥均匀性差、干燥时间长的问题,提出了一种新型的太阳能辅助热泵(SAHP)仓内粮食干燥系统。通过数值和实验研究了不同操作参数对干燥性能的影响。实验结果表明，在给定条件下，太阳能集热器的热效率和热泵的COP分别达到63%和5.03。SAHP 系统的平均加热能力为 130.2 kW，与冬季典型晴天下的模拟结果一致。干燥42小时后，3760吨粮食的平均含水量从12.9%下降到12.5%。所提出系统的特定水分提取率和粮仓的火用效率为 1。分别为 934 kg/kWh 和 40.27%。SAHP谷物干燥与相同干燥重量的谷物干燥机相比，运行成本从5.57美元/吨下降到1.43美元/吨。在相同的含水率降低率下，与机械通风干燥相比，日干燥能力从166 t/d提高到334 t/d。本研究为今后进一步开展应用于仓内粮食干燥的 SAHP 系统的研究提供指导。