1、 第 1 页 外文翻译 The Applications of Heat pumps 1.Heat pumps in industry 1). Systems Relatively few heat pumps are currently installed in industry. However, as environmental regulations become stricter, industrial heat pumps can become an important technology to reduce emissions, improve efficiency, and
2、limit the use of ground water for cooling To ensure the sound application of heat pumps in industry, processes should be optimised and integrated. Through process integration improved energy efficiency is achieved by thermodynamically optimising total industrial processes. An important instrument fo
3、r process integration is pinch analysis, a technology to characterise process heat streams and identify possibilities for heat recovery. Such possibilities may include improved heat exchanger networks, cogeneration and heat pumps. Pinch analysis is especially powerful for large, complex processes wi
4、th multiple operations, and is an excellent instrument to identify sound heat pump opportunities. Industrial applications show a great variation in the type of drive energy, heat pump size, operating conditions, heat sources and the type of application. The heat pump units are generally designed for
5、 a specific application, and are therefore unique. The major types of industrial heat pumps are: o Mechanical vapour recompression systems (MVRs), classified as open or semi-open heat pumps. In open systems, vapour from an industrial process is compressed to a higher pressure and thus a higher tempe
6、rature, and condensed in the same process giving off heat. In semi-open systems, heat 第 2 页 from the recompressed vapour is transferred to the process via a heat exchanger. Because one or two heat exchangers are eliminated (evaporator and/or condenser) and the temperature lift is generally small, th
7、e performance of MVR systems is high, with typical coefficients of performance (COPs) of 10 to 30. Current MVR systems work with heat-source temperatures from 70-80 篊 , and deliver heat between 110 and 150 篊 , in some cases up to 200 篊 . Water is the most common working fluid (i.e. recompressed proc
8、ess vapour), although other process vapours are also used, notably in the (petro-) chemical industry. o Closed-cycle compression heat pumps are described in the section Heat pump technology . Currently applied working fluids limit the maximum output temperature to 120 篊 . o Absorption heat pumps (Ty
9、pe I) are not widely used in industrial applications. Some have been realised to recover heat from refuse incineration plants, notably in Sweden and Denmark. Current systems with water/lithium bromide as working pair achieve an output temperature of 100篊 and a temperature lift of 65 篊 . The COP typi
10、cally ranges from 1.2 to 1.4. The new generation of advanced absorption heat pump systems will have higher output temperatures (up to 260 篊 ) and higher temperature lifts. o Heat transformers (Type II) have the same main components and working principle as absorption heat pumps. With a heat transfor
11、mer waste heat can be upgraded, virtually without the use of external drive energy. Waste heat of a medium temperature (i.e. between the demand level and the environmental level) is supplied to the evaporator and generator. Useful heat of a higher temperature is given off in the absorber. All curren
12、t systems use water and lithium bromide as working pair. These heat transformers can achieve a delivery temperatures up to 150 篊 , typically with a lift of 50 篊 . COPs under these conditions range from 0.45 to 0.48. 第 3 页 o Reverse Brayton-cycle heat pumps recover solvents from gases in many process
13、es. Solvent loaden air is compressed, and then expanded. The air cools through the expansion, and the solvents condense and are recovered. Further expansion (with the associated additional cooling, condensation and solvent recovery) takes place in a turbine, which drives the compressor. 2). Applicat
14、ions Industrial heat pumps are mainly used for: o space heating； o heating and cooling of process streams； o water heating for washing, sanitation and cleaning； o steam production； o drying/dehumidification； o evaporation； o distillation； o concentration. When heat pumps are used in drying, evaporat
15、ion and distillation processes, heat is recycled within the process. For space heating, heating of process streams and steam production, heat pumps utilise (waste) heat sources between 20 篊 and 100 篊 . The most common waste heat streams in industry are cooling water, effluent, condensate, moisture,
16、and condenser heat from refrigeration plants. Because of the fluctuation in waste heat supply, it can be necessary to use large storage tanks for accumulation to ensure stable operation of the heat pump. o Space heating: Heat pumps can utilise conventional heat sources for heating of greenhouses and industrial buildings, or they can recover industrial waste heat that could
