In view of high discharge temperature of compressor, the heating performance attenuated seriously, even unable to work properly and other issues of normal heat pump air conditioning system for electric vehicles under low temperature conditions, a gas-mixing heat pump air conditioning system for pure electric vehicles is designed. Based on the first law of thermodynamics and coupling properties among all components, the mathematical model of this system is established. The analog computation of main performance parameters of this system is carried out by this model, having a better match in comparison with experimental results. By simulation, the results show that the system can effectively solve the problems of high exhaust temperature from compressor and heating performance attenuation seriously of non-gas-mixing heat pump air conditioning system for pure electric vehicles under low temperature condition.

Mineral sepiolite as inorganic carrier, lauric acid(LA)-stearic acid(SA)as binary PCM(phase change material), CTAB as modifier, ethanol as solvent, mineral energy storage residential composite was prepared by intercalation, and the properties of composites were characterized using thermogravimetry(TG)/differential thermal analysis(DTA),scanning electron microscope(SEM),X-ray diffraction(XRD).Orthogo-nal experimental results show that the optimum proportion of composite materials is A3B2C1D3, the initial phase change temperature is 31.44 °C, phase transition peak temperature is 35.25°C, a wide range of endothermic peak is between 30.0~40.0°C, scope of phase change temperature is 3.81. LA-SA eutectic mixture could be retained by adding into 42.3 wt% porous sepiolite, treated at 80 °C. The weight loss of the composites is no more than 2% when melting/freezing cycling within 100°C, so it has good thermal reliability when applied to building material. Mainly due to relatively high content of mineral impurity, high temperature and CTAB can significantly help improve adsorption rate of mineral sepiolite. Sepiolite as a carrier material has features with low cost, broad sources, non-toxic and non-pollution. The composite material is a healthy residential energy-saving material, and it provides a good prospect for the realization of building energy efficiency, regulating room temperature in summer, and improving human comfort.

For particular commercial kitchen, using CFD software to build model according to the actual operation condition uttermost, adopting the exhaust system of up-suction hood, the effect of exhaust airflow rate on working temperature,velocity,CO2 concentration at main site in commercial kitchen is studied. According to the common four calculation methods of airflow rate of exhaust hood, the simulation results shows 4.81 m3/s of exhaust system can realize eliminating harmful gas quickly and effectively, IAQ is good relatively. Based on of it, additional airflow rate can not improve emissions effect and operating conditions obviously, whereas it can be detrimental to save energy. The simulation results help design exhaust system.

Indoor air quality of commercial kitchen is investigated and analyzed through velocity, temperature, humidity, and CO2 concentration under different air change rate and supply air temperature. the best air change rate is 30 times per hour and air supply temperature is 301.15K for kitchen, the mean value of the minimum velocity and standard deviation is 0.410m/s and 0.129 respectively, the maximum of the average concentration of CO2 is 659.78ppm, which is less than the acceptance criteria (CO2<1000ppm), and the energy utilization coefficient is maximum of 1.352. Research results show that this air supply mode can optimize indoor air quality.

A experimentally study has been carried out to predict airflow rate, temperature field and velocity field for different chimney gap and heat flux. Results showed that, for veritical solar chimney,there is an optimum ratio of chimney width-to height to achieve a maximum airflow rate. The optimum ratio is about 1：2. Meanwhile,temperature and velocity field of solar chimney channel were analyzed. The air temperature and the velocity approaching to the surface of the heated wall are higher than that away from the surface of the heated wall.