Study on night heat dissipation characteristics of solar collector system of an office building under different conditions in Tibetan area of western Sichuan

In order to study the night heat dissipation characteristics and thermal insulation performance of the evacuated tube collector system combining with the heat storage water tank in an office building, tests and calculates the heat transfer fluid temperature in the evacuated tube collector system, the night heat dissipation and average heat loss coefficient of the system. Analyses the heat dissipation properties and laws of the evacuated tube collector system, and verifies the influence of the improvement approaches on heat dissipation. Results indicate that when environment temperature ranges from -10 ℃ to 5 ℃, the lowest heat transfer fluid temperature ranges from 20 ℃ to 40 ℃, and the average heat loss coefficient is 0.489 W/(℃·m2) during the testing nights. The analysis on the heat dissipation of the system can contribute to evaluate its insulation performance and the effects of improvement approaches, which can provide a reference for enhancing the applications of solar heating system in Tibetan area of western Sichuan.