Parabolic trough receiver is a key component to convert solar energy into thermal energy in the parabolic trough solar system. The heat loss of the receiver has an important influence on the thermal efficiency and the operating cost of the power station. In this paper, conduction and radiation heat losses are analyzed respectively to identify the heat loss mechanism of the receiver. A 2-D heat transfer model is established by using the direct simulation Monte Carlo method for rarefied gas flow and heat transfer within the annulus of the receiver to predict the conduction heat loss caused by residual gases. The numerical results conform to the experimental results, and show the temperature of the glass envelope and heat loss for various conditions in detail. The effects of annulus pressure, gas species, temperature of heat transfer fluid, and annulus size on the conduction and radiation heat losses are systematically analyzed. Besides, the main factors that cause heat loss are analyzed, providing a theoretical basis for guiding the improvement of receiver, as well as the operation and maintenance strategy to reduce heat loss.

抛物槽式接收器是抛物槽式太阳能系统中将太阳能转换成热能的关键组件。接收器的热损失对电站的热效率和运营成本具有重要影响。本文分别对传导和辐射热损失进行了分析，以确定接收器的热损失机理。通过使用直接模拟蒙特卡洛方法建立二维传热模型，对稀薄气体的流动和接收器环空内的传热进行预测，以预测由残留气体引起的传导热损失。数值结果与实验结果吻合，并详细显示了各种条件下的玻璃外壳温度和热损失。环空压力，气体种类，传热流体温度的影响，并系统地分析了环空大小对传导和辐射热损失的影响。此外，分析了造成热量损失的主要因素，为指导接收机的改进提供了理论依据，并为减少热量损失提供了操作和维护策略。