The Study Of Large Enthalpy Difference Evaporative Cooling Condenser

In the field of building energy efficiency, evaporative cooling technology is more and more attention by cooling, air conditioning, and refrigeration industry. Thus, it has important significance for energy conservation and emissions reduction to improve the efficiency of evaporation-cooling device.This paper proposes a large enthalpy difference evaporative cooling water-cooled condenser. This unit series evaporative condenser and water-cooled condenser, the condensation zone of refrigerant vapor is divided into a high-temperature sensible heat evaporation condensation zone and low-temperature latent heat water-cooled condensing zone. In the evaporation condensation zone, spray water and air exchange heat with high temperature refrigerant vapor of coil, air is heated secondary, heat capacity increase, and air enthalpy difference of import and export increase. This unit has compact structure, great heat exchange density and the spray water circulation water volume is small, it is a highly efficient low consumption of the cooling equipment.The work process of this unit involves the flow characteristics and heat transfer and mass transfer characteristics of gas-liquid two phase flow coupling, the flow field is complex, it is necessary to carry out theoretical calculation, experimental research and numerical simulation.First of all, on the basis of the theory of heat and mass transfer in, the mathematical model of evaporative cooler plate of district and heat and mass transfer packing area was built. The mathematical model putting coil area and filling area in series is written by MATLAB, to predict the thermal performance of large enthalpy difference evaporative cooling condenser under different conditions. Secondly, by building the test bench for testing the thermal performance of large enthalpy difference evaporative cooling condenser, further study the effect of spray water density and air flow to the cooling performance, provide the basis of the experimental data for numerical simulation study. This article also uses FLUENT to simulate the heat transfer process inside the large enthalpy difference evaporative cooling condenser, and analyze the spray water and air heat transfer mechanism.Through the theoretical analysis, numerical simulation and experiment test, we get the following conclusions:Under a fixed amount of wind conditions, when increasing the spray water flow, the outlet temperature of spray water rise before leveling off, the temperature of the fluid within the coil drop before leveling off. When the density of spray water is in the range of 2.5 kg/(m2·s) to 3.0kg/(m2·s), the gas flow in the range of 2.0 kg/(m2·s) to 2.8 kg/(m2·s), the effect of evaporative cooler is close to the optimal effect.With the increase of spray water density, the heat transfer coefficient αw of water film outside the tube nonlinear increases, its tendency tends to be gentle. The heat transfer coefficient aw can be fit to an equation, with spraying water density and diameter as variable:αw=302(Γ/d0)0.67.In the large enthalpy difference evaporative cooling water-cooled condenser, the spray water has a big temperature difference and small flow, the refrigerant cooling system energy consumption can be reduced by 1%～23%, the air system energy consumption can be reduced by 2%～12%, the air enthalpy difference between the import and export can be increased by about 5%～23%, compared with some other evaporative cooler product.Through the study of large enthalpy difference evaporative cooling condenser, this topic has enriched the theory and application of evaporative cooler, providing a reference for further research on the optimization design of the performance of the evaporative cooler and cooling system optimization design of energy saving.