Study On Shell And Tube Condenser Of Commercial Air Conditioning

With the rapid development of economy in our country, the use of air conditioningincreases widely. As large energy consumption, the air conditioning energy consumptionof buildings takes up about10%of the society total energy consumption of the society.In the environment of advocating energy conservation and emissions reduction, how toreduce building energy consumption, especially air conditioning energy consumption isan important topic. And improving the performance of heat exchanger in airconditioning system means much to reduce the energy consumption of air conditioningsystem. This paper takes the actual production issues of one of refrigeration equipmentcompany as the research background, using the computer design and advanced theories,methods and techniques of numerical simulation, carries on the design and theoptimization of heat transfer and flow to shell and tubecondenser of air-conditioningchillers for commercial.Due to the irregular geometry of the bundle, the flow situation is complex there.It’s hard to calculate the film condensation heat transfer coefficient of the tube bundleaccurately when steam condenses between the condensing tubes of shell side of thecondenser. For refrigerant condensing between tube bundles, the influence of thecondensate drop between tube and the speed of steam through the tube bundle should beconsidered. Using case-by-ranked calculation method, the average heat transfercoefficient of condenser between multi-layer bundles was calculated and compared withthe literature results. It shows that the tube row of condensate drop and the speed of thesteam through the tube bundle impacts much on condensing liquid film length, whichaffects the heat transfer coefficient.According to the constructions characteristics of the condenser, heat transfer andpressure drop mathematical model of the condenser was modified. And this model wasapplied to calculate the product of the company. The result was perfect. The maximumerror of effective heat transfer area is20%, and the maximum error of pressure drop is15%. For the convenience of design and calculation, a tube and shell condenser designcalculation software was developed using Visual Basic in this paper.Numerical simulation was made to study the flow characteristics of the shell sideof shell and tube condensers. Because of the existence of a baffle in the condenser, theflow of the refrigerant vapor in the condenser was impacted, so was the heat transfer performance. Optimization was made to LSBLG400/M screw water chiller condenser. Ascheme of using a45°upward baffle to replace the original one was promoted. Whichcan make full use of the area of the heat exchanger and the vapor can get the maximumcondensation. The length and height of the baffle was optimized by the single stack. Theoptimized length is800mm and height is290mm. This optimization method resultedwell and can be applied to the optimal design of the other products.