Study On The Thermal Properties And Ventilation And Cooling System Of The Laboratory Of Desert Environment Simulation

The laboratory of desert environment simulation is studied in this paper. Its thermal characteristics of the building envelop is investigated. Based on the problems during laboratory operation the temperature is simulated and the airflow is improved through the technologies of ventilation and frequency conversion. And in order to reduce the cooling load a ventilation and coolant system is put above the solar simulators, which are the main heat source of the lab. Finally, the temperature field and velocity field of the improved laboratory are simulated through CFD techniques. Based on the simulation results a better program is found out to help the laboratory reconstruction.The study of the thermal characteristics is composed of the analysis and calibration of the material and thickness of the heat insulation layer by analyzing the characteristics of the building envelop, the arrangement of the different layers and the evaluation of the reasonableness of the building envelop. It has been found that thermal design has great effect on the capital investment and running cost of the environment simulation system.The simulation on temperature is improved by putting an exhaust hood above solar simulators based on the combination of ventilating and cooling theories with current refrigerating and heating system in the lab. The exhaust hood can induce outdoor air for temperature adjustment and both the radiation intensity and temperature in model testing area can meet the requirements as a result. The flow field is improved by adopting flow-sharing draft-induced measures to produce uniform gust in model testing area. Additionally, the flow velocity can be changed through frequency conversion fans.After adding the exhaust hood and flow rectifiers the temperature field and velocity field of the model testing area are studied and the two fields is compared under different positions of exhaust pipe and different air velocities of forced draft fan. The simulation results show that the exhaust hood can effectively discharge the heat from solar simulators and it can make the temperature in model testing area meet the simulation requirements by using current refrigerating and heating system. The position of exhaust pipe has little effect on flow field. When the air velocity is 1m/s, the temperature contours become denser near the solar simulators, showing temperature gradient. However, with the increase of air velocity the temperature in model testing area tends to be uniform, which meets the simulation requirements. By taking effective flow-sharing and draft-induced measures air flow short-circuit in fans' outlets and scroll phenomenon in model testing area can be eliminated and a uniform velocity field can be produced. The larger the air velocity, the better uniformity of temperature field can be achieved. But some air will get out of the work area with large air velocity, causing energy lost of the system. Moreover, large air velocity will increase the noise and electricity consumption of fans. So the optimal air velocity should be found out in further study.