| Heat transfer enhancement is one kind of new energy conservation technology for significantly improving heat transfer efficiency. Its main content is adopting strengthen heat transfer element, improving on heat exchanger structure, increasing heat transfer efficiency, so as to make facility investment and operating expense lowest. To design novel high-efficiency heat exchanger, many kinds of heat exchanger process were investigated. How to enhance the heat transfer is not only a problem which has to be resolved for modern industry development, but also an urgent task about exploiting new energy resources and developing energy conservation. Recently, to mainly use different dentiform spiral-surface heat- transfer tube as an heat transfer improvement method, such as: spiral fluted tube, etc. Enhanced heat transfer tube with spiral-surface has simple frame, cheap cost, and wide application range. Only little dirt can adhere to it and is easy to be washed. It has distinct strengthen effect, and can improve chief heat transfer coefficient at 35-40% comparing with smooth tube exchanger which has same volume and pump power consumption. So lots of people are interested in it.Falling film evaporator with enhanced heat transfer tubes is a kind of effective energy conservation facility, and has obviously advantage than other types of evaporator. Falling film evaporation technology is film evaporation, because phase change happens in the flowing film and film flow is on the side of evaporation, evaporator has higher heat transfer coefficient, higher heat flux, heat transfer at lower different temperature and more excellent performance at low temperature. For refrigeration, failing film evaporation technology has higher heat transfer coefficient and lower cost than flooding evaporator. Above advantages were proofed in this paper by experimental research on screw water chiller unit with falling film evaporator and comparing with flood evaporator with same cooling capacity in performance and cost. |
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