外文翻译---热泵的应用(编辑修改稿)

外文翻译---热泵的应用(编辑修改稿)内容摘要：

dryers generally have high performance (COP 57), and often improve the quality of the dried products as pared with traditional drying methods. Because the drying is executed in a closed system, odours from the drying of food products etc. are reduced. Both closedcycle 第 5 页 pression heat pumps and MVR systems are used. o Evaporation and distillation processes: Evaporation and distillation are energyintensive processes, and most heat pumps are installed in these processes in the chemical and food industries. In evaporation processes the residue is the main product, while the vapour (distillate) is the main product in distillation processes. Most systems are open or semiopen MVRs, but closedcycle pression heat pumps are also applied. Small temperature lifts result in high performance with COPs ranging from 6 to 30. 2． Heat pumps in residential and mercial buildings 1） .Functions Heat pumps for heating and cooling buildings can be divided into four main categories depending on their operational function: o Heatingonly heat pumps, providing space heating and/or water heating. o Heating and cooling heat pumps, providing both space heating and cooling. The most mon type is the reversible airtoair heat pump, which either operates in heating or cooling mode. Large heat pumps in mercial/institutional buildings use water loops (hydronic) for heat and cold distribution, so they can provide heating and cooling simultaneously. o Integrated heat pump systems, providing space heating, cooling, water heating and sometimes exhaust air heat recovery. Water heating can be by desuperheating only, or by desuperheating and 第 6 页 condenser heating. The latter permits water heating when no space heating or cooling is required. o Heat pump water heaters, fully dedicated to water heating. They often use air from the immediate surroundings as heat source, but can also be exhaustair heat pumps, or desuperheaters on airtoair and watertoair heat pumps. Heat pumps can be both monovalent and bivalent, where monovalent heat pumps meet the annual heating and cooling demand alone, while bivalent heat pumps are sized for 2060% of the maximum heat load and meet around 5095% of the annual heating demand (in a European residence). The peak load is met by an auxiliary heating system, often a gas or oil boiler. In larger buildings the heat pump may be used in tandem with a cogeneration system (CHP). In residential applications room heat pumps can be reversible airtoair heat pumps (ductless packaged or split type units). The heat pump can also be integrated in a forcedair duct system or a hydronic heat distribution system with floor heating or radiators (central system). In mercial/institutional buildings the heat pump system can be a central installation connected to an air duct or hydronic system, or a multizone system where multiple heat pump units are placed in different zones of the building to provide individual space conditioning. Efficient in large buildings is the waterloop heat pump system, which involves a closed water loop with multiple heat pumps linked to the loop to provide heating and cooling, with a cool。