Numerical Simulation Of Loop Heat-pipe Heat-exchanger For Air Conditioning

As one kind of heat pipes, the loop heat pipe is provided with the excellent heat transfer performance. In the case of increasing air-conditioning energy consumption, the heat pipe exchangers for air-conditioning systems show immense advantages in the domains of the heat recovery of energy-saving and the air supply combined with cooling coils scholars of many countries have done a lot of research both in the theory and experiments.Aiming at the loop heat pipe with non-wick and non-height difference, the paper probed into the application and energy-saving analysis of the loop heat pipe which used in the air-conditioning system firstly, including its configuration, working fluid and the best filling rate. Secondly, the paper analyzed the heat transfer theory and improved the calculation method of heat exchange capacity of this loop heat pipe in the air-conditioning system. Lastly, Computational fluid dynamics (CFD) software was used to simulate the phase transition of the single heat pipe and the heat transfer effect of heat pipe exchangers, which is based on the two-phase model the addition of the user-defined function(UDF). Moreover, the heat pipe was optimized based on the simulation results. Also the heat transfer effect by the loop heat pipe exchanger evaporation segment and condensation segment was simulated.The relationships of out-let velocity, dryness and temperature with the filling rate and heat flux were obtained based on the simulation, and the correctness of simulation results was checked out by experiments. Meanwhile, the effect of different rows, pipe diameter and spacing on the heat exchange was simulated. The result indicates that the height, diameter and rows of heat pipe have visible influence on the heat pipe exchanger effect, but spacing has a neglected influence. It will have a better heat exchanger when the loop heat pipe is smaller of the diameter and longer of the height or inverted triangle arrangement.