[雙語翻譯]--換熱器外文翻譯--關(guān)于在熱電聯(lián)產(chǎn)（chp）系統(tǒng)中廢熱回收的熱交換器的設(shè)計（英文）

1、DESIGN OF HEAT EXCHANGER FOR HEAT RECOVERY IN CHP SYSTEMS Theodore A. Kozman Bimaldeep Kaur Jim Lee Associate Professor Research Assistant Professor Department of Mechanical Engineering P. O. Box 44170, Room 244

2、 CLR Hall University of Louisiana at Lafayette Lafayette, LA 70504-2250, USA ABSTRACT The objective of this research is to review issues related to the design of heat recovery unit in Combined Heat and Power (CHP) s

3、ystems. To meet specific needs of CHP systems, configurations can be altered to affect different factors of the design. Before the design process can begin, product specifications, such as steam or water pressures a

4、nd temperatures, and equipment, such as absorption chillers and heat exchangers, need to be identified and defined. The Energy Engineering Laboratory of the Mechanical Engineering Department of the University of Lou

5、isiana at Lafayette and the Louisiana Industrial Assessment Center has been donated an 800kW diesel turbine and a 100 ton absorption chiller from industries. This equipment needs to be integrated with a heat exchange

6、r to work as a Combined Heat and Power system for the University which will supplement the chilled water supply and electricity. The design constraints of the heat recovery unit are the specifications of the turbine

7、and the chiller which cannot be altered. INTRODUCTION Combined Heat and Power (CHP), also known as cogeneration, is a way to generate power and heat simultaneously and use the heat generated in the process for

8、various purposes. While the cogenerated power in mechanical or electrical energy can be either totally consumed in an industrial plant or exported to a utility grid, the recovered heat obtained from the thermal energ

9、y in exhaust streams of power generating equipment is used to operate equipment such as absorption chillers, desiccant dehumidifiers, or heat recovery equipment for producing steam or hot water or for space and/or pr

10、ocess cooling, heating, or controlling humidity. Based on the equipment used, CHP is also known by other acronyms such as CHPB (Cooling Heating and Power for Buildings), CCHP (Combined Cooling Heating and Power), BC

11、HP (Building Cooling Heating and Power) and IES (Integrated Energy Systems). CHP systems are much more efficient than producing electric and thermal power separately. According to the Commercial Buildings Energy Con

12、sumption Survey, 1995 [14], there were 4.6 million commercial buildings in the United States. These buildings consumed 5.3 quads of energy, about half of which was in the form of electricity. Analysis of survey data

13、shows that CHP meets only 3.8% of the total energy needs of the commercial sector. Despite the growing energy needs, the average efficiency of power generation has remained 33% since 1960 and the average overall effi

14、ciency of generating heat and electricity using conventional methods is around 47%. And with the increase in prices in both electricity and natural gas, the need for setting up more CHP plants remains a pressing issu

15、e. CHP is known to reduce fuel costs by about 27% [15] and significantly reduce emissions of NOx, SOx, and CO released into the atmosphere. The objective of this research is to review issues related to the design of

16、 heat recovery unit in Combined Heat and Power (CHP) systems. To meet specific needs of CHP systems, configurations can be altered to affect different factors of the design. Before the design process can begin, prod

17、uct specifications, such as steam or water pressures and temperatures, and equipment, such as absorption chillers and heat exchangers, need to be identified and defined. The Mechanical Engineering Department and the

18、 Industrial Assessment Center at the University of Louisiana Lafayette has been donated an 800kW diesel turbine and a 100 ton absorption chiller from industries. This equipment needs to be integrated to work as a Com

19、bined Heat and Power system for the University which will supplement the chilled water supply and electricity. The design constraints of the heat recovery unit are the specifications of the turbine and the chiller wh

20、ich cannot be altered. Integrating equipment to form a CHP system generally does not always present the best solution. In our case study, the absorption chiller is not able to utilize all of the waste heat from t

21、he turbine exhaust. ESL-IE-09-05-25 Proceedings of the Thirty-First Industrial Energy Technology Conference, New Orleans, LA, May 12-15, 2009 provides chilled water. An advantage of absorption chillers is that they don’

22、t require any permits or emission treatment [2] Exhaust gas at 800°F comes out of the turbine at a flow rate of 48,880 lbs/h [7]. One important constraint during the design of the CHP system was to control the f

23、inal temperature of this exhaust gas. This meant utilizing as much heat as required from the exhaust gas and subsequently bringing down the exit temperature. After running different iterations on temperature calculat

24、ions, it was decided to divert 35% of the exhaust air to the heat exchanger while the remaining 65% is directed to go up the stack. This is achieved by using a diverter damper. In addition, diverting 35% of the gas r

25、elieves the problem of back pressure build-up at the end of the turbine. A diverter valve can also used at the inlet side of the heat exchanger which would direct the exhaust gas either to the heat exchanger or out o

26、f the bypass stack. This takes care of variable loads requirement. Inside the heat exchanger, exhaust gas enter the shell side and heats up water running in the tubes which then goes to the absorption chiller. These

27、chillers run on either steam or hot water. The absorption chiller donated to the University runs on hot water and supplies chilled water. A continuous water circuit is made to run through the chiller to take away he

28、at from the heat input source and also from the chilled water. The chilled water from the absorption chiller is then transferred to the existing University chilling system unit or for another use. Thermally Activat

29、ed Devices Thermally activated technologies (TATs) are devices that transform heat energy for useful purposed such as heating, cooling, humidity control etc. The commonly used TATs in CHP systems are absorption chil

30、lers and desiccant dehumidifiers. Absorption chiller is a highly efficient technology that uses less energy than conventional chilling equipment, and also cools buildings without the use of ozone-depleting chlorofluo

31、rocarbons (CFCs). These chillers can be powered by natural gas, steam, or waste heat. Desiccant dehumidifiers are used in space conditioning by removing humidity. By dehumidifying the air, the chilling load on th

32、e AC equipment is reduced and the atmosphere becomes much more comfortable. Hot air coming from an air- to-air heat exchanger removes water from the desiccant wheel thereby regenerating it for further dehumidification

33、. This makes them useful in CHP systems as they utilize the waste heat. An absorption chiller is mechanical equipment that provides cooling to buildings through chilled water. The main underlying principle behind the

34、 working of an absorption chiller is that it uses heat energy as input, instead of mechanical energy. Though the idea of using heat energy to obtain chilled water seems to be highly paradoxical, the absorption chille

35、r is a highly efficient technology and cost effective in facilities which have significant heating loads. Moreover, unlike electrical chillers, absorption chillers cool buildings without using ozone-depleting chlorof

36、luorocarbons (CFCs). These chillers can be powered by natural gas, steam or waste heat. Absorption chiller systems are classified in the following two ways: 1. By the number of generators. i) Single effect chille

37、r – this type of chiller, as the name suggests, uses one generator and the heat released during the absorption of the refrigerant back into the solution is rejected to the environment. ii) Double effect chiller – th

38、is chiller uses two generators paired with a single condenser, evaporator and absorber. Some of the heat released during the absorption process is used to generate more refrigerant vapor thereby increasing the chill

39、er’s efficiency as more vapor is generated per unit heat or fuel input. A double effect chiller requires a higher temperature heat input to operate and therefore its use in CHP systems is limited by the type of

40、electrical generation equipment it can be used with. iii) Triple effect chiller – this has three generators and even higher efficiency than a double effect chiller. As they require even higher heat input temperatur

41、es, the material choice and the absorbent/refrigerant combination is limited. 2. By type of input: i) Indirect-fired absorption chillers – they use steam, hot water, or hot gases from a boiler, turbine, engine

42、generator or fuel cell as a primary power input. Indirect-fired absorption chillers fit well into the CHP schemes where they increase the efficiency by utilizing the otherwise waste heat and producing chilled wat