Yingying Tan

Environment and Energy Challenge of Air Conditioner in China

China has been one of the worlds largest producers and consumers of air conditioners. Air conditioners meet the demands for human comfort, but they cause serious problems, such as stratospheric ozone depletion, global warming, power failure, electricity demand peak and simplification of energy consumption structure. All problems are analysized. The future studies on development of air conditioners are discussed.

Research Progress of Diffusion Absorption Refrigeration Technology

Compared with the gas-compressed refrigeration system, the diffusion absorption refrigeration cycle has no moving part and the associated noise and vibration. It can be operated without any electric input and driven by various energy sources, has no the problem of the substitute of CFC, furthermore it has positive significance in energy conservation, off peak, environmental protection, and promoting the use of gas. So it has broad application prospects as a kind of absorption refrigeration mode. In the development of diffusion absorption refrigeration technology, the performance of diffusion absorption refrigeration system has been improved and enhanced continuously. The paper presents and discusses the recent research progress of diffusion absorption refrigeration which contains design of bubble pump, adjustment and optimization of operation parameters, utilization of low-grade thermal energy and selection of working medium. The research direction of diffusion absorption refrigeration in the future is suggested.

Study on Energy Efficiency of a Low Temperature Refrigeration System

Based on conservation of mass, total mass balance equation and component mass balance equation, mathematical models of thermodynamic for the auto cascade refrigeration cycle are established. Thermophysical properties in solving the governing equation are called from the NIST REFPROP7.0. Thermodynamic properties of the auto cascade refrigeration cycle using binary mixtures, namely, R170/R290, R23/R227ea, R116/R134a, R23/R134a, R170/R600a, R170/R600 and R170/R152a as refrigerants is evaluated. R170/R600a is selected for the low temperature refrigeration system, and the influences of cycle mole fraction, compression ratio and evaporating pressure on the cycle performance are analysed.

Simulation of Critical Flux through Adiabatic Capillary Tubes Based on Artificial Neural Network

Evaluating the critical flux in capillary tubes is the key to the research on flow characteristics in capillary tubes. The mathematical model of refrigerant flow through the capillary tubes was presented. The numerical solutions were obtained based on the program made. Data derived from capillary tube theoretical models were used as example collection to train the back propaganda(BP)network model in order to evaluate the critical flux through capillary tubes. The results are satisfactory. Compared with finite difference numerical computation method, the computation of the critical flux based on neural network is more useful to engineering design of capillary tubes.