Design And Research On Condenser Of Air-cooled Condensing Unit

The Tube-Fin condenser is a key component of the air-cooled compression condensing unit,and its heat exchange effect directly affects the energy efficiency of the entire unit.This subject is based on the performance optimization project of the series products of air-cooled condensing units for cold storage.It studies the design and optimization of small-diameter tube-type air-cooled condensers,replaces the small-diameter of the condenser of the research prototype,and replaces the compressor and other matching of components;introduction of condenser simulation method based on graph theory and condenser simulation method based on EVAP-COND software;three types of 6 in 3 out,8 in 4 out and 6 in 6 out based on the prototype condenser process layout plan,through simulation analysis of the heat transfer performance of each plan under different working conditions,and test analysis.Standard working condition simulation results show that the heat exchange volume and pressure loss of scheme A are the largest,scheme B is the second,and scheme C is the smallest.The comparison of refrigerant state changes shows that the split-combination arrangement can effectively strengthen the heat exchange coefficient of the supercooling section and increase the overheating coefficient.The heat exchange length of the cold section improves the supercooling of the effluent,but it also increases the pressure loss.The simulation results of variable upwind speed show that the effect of increasing the upwind speed on the heat exchange volume is more significant when the upwind speed is less than 2m / s,and the improvement effect is weaker when it is greater than 2m / s,and the heat exchange capacity is no longer after 2.4m / s.Increase.The heat exchange effect of the split-combination arrangement in the low wind speed area is greatly affected by the oncoming wind speed,and the split-combination arrangement in the high wind speed area has better heat transfer performance.The simulation results of variable windward temperature show that the higher the windward temperature is,the smaller the heat transfer amount is and the greater the pressure loss is.And the higher the windward temperature,the greater the change trend of heat exchange amount and pressure loss.And the heat exchange effect of the split-combination arrangement is more affected by the windward temperature,which mainly depends on the refrigerant dryness at the merger: the lower the dryness at themerger,the smaller the refrigerant pressure loss after the merger,and the pipeline merge The more significant the heat transfer enhancement effect in the cold section,the better the comprehensive heat transfer performance.The results of variable mass flow simulation show that the three schemes have different optimal heat exchange mass flow areas.After exceeding the optimal heat exchange mass flow area,the heat exchange amount begins to decrease.The area of the best heat exchange mass flow rate is mainly affected by the average refrigerant flow rate.The higher the average flow rate,the smaller the refrigerant mass flow rate in the best heat exchange area.The test results show that as the ambient temperature increases,the cooling capacity of the unit decreases,the power consumption of the compressor increases,and the rate of change is faster.The condensing temperature of the split-combined arrangement at high ambient temperature is lower,and the overall heat exchange performance is better.After replacing with ?7.94 internally threaded tube,the copper consumption of the condenser is reduced by 5.83%,and the cooling capacity of the three schemes under standard operating conditions is increased by 6.85%,3.04% and 2.1% respectively compared to the prototype.The compressor power They decreased by 4.38%,3.36%and 2.48%,respectively,and COP increased by 9.42%,6.62% and 4.71%,respectively.Among them,the supercooling degree of the liquid output of the 6 in 3 out and 8 in 4output units is significantly improved compared to the 6 in 6 out and prototype.The supercooling degrees of the four solutions are 6.8 ?,5.5 ?,4.1 ? and 3.9 ?.