【文章內(nèi)容簡介】 , humidity control etc. The monly used TATs in CHP systems are absorption chillers 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 ozonedepleting chlorofluorocarbons (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 the AC equipment is reduced and the atmosphere bees much more fortable. Hot air ing from an airtoair heat exchanger removes water from the desiccant wheel thereby regenerating it for further dehumidification. 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 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 chiller 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 ozonedepleting chlorofluorocarbons (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 chiller – 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 – this 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 chiller’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 大 連海洋大學 2021 屆畢業(yè)設計 外文翻譯（英文） systems is limited by the type of 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 temperatures, the material choice and the absorbent/refrigerant bination is limited. 2. By type of input: i) Indirectfired absorption chillers – they use steam, hot water, or hot gases from a boiler, turbine, engine generator or fuel cell as a primary power input. Indirectfired absorption chillers fit well into the CHP schemes where they increase the efficiency by utilizing the otherwise waste heat and producing chilled water from it. ii) Directfired absorption chillers – they contain burners which use fuel such as natural gas. Heat rejected from these chillers is used to provide hot water or dehumidify air by regenerating the desiccant wheel. An absorption cycle is a process which uses two fluids and some heat input to produce the refrigeration effect as pared to electrical input in a vapor pression cycle in the more familiar electrical chiller. Although both the absorption cycle and the vapor pression cycle acplish heat removal by the evaporation of a refrigerant at a low pressure and the rejection of heat by the condensation of refrigerant at a higher pressure, the method of creating the pressure difference and circulating the refrigerant remains the primary difference between the two. The vapor pression cycle uses a mechanical pressor that creates the pressure difference necessary to circulate the refrigerant, while the same is achieved by using a secondary fluid or an absorbent in the absorption cycle [11]. The primary working fluids ammonia and water in the vapor pression cycle with ammonia acting as the refrigerant and water as the absorbent are replaced by lithium bromide (LiBr) as the absorbent and water (H2O) as the refrigerant in the absorption cycle. The process occurs in two shells the upper shell consisting of the generator and the condenser and the lower shell consisting of the evaporator and the absorber. Heat is supplied to the LiBr/H2O solution through the generator causing the refrigerant (water) to be boiled out of the solution, as in a distillation process. The resulting water vapor passes into the condenser where it is condensed back into the liquid state using a condensing medium. The water then enters the evaporator where actual cooling takes place as water is passes over tubes containing the fluid to be cooled. Heat Exchanger A very low pressure is maintained in the absorberevaporator shell, causing the water to boil at a very low temperature. This results in water absorbing heat from the medium to be cooled and thereby lowering its temperature. The heated low pressure vapor then returns to the absorber where it mixes with the LiBr/H2O solution low in water content. Due to the solution’s low water 大 連海洋大學 2021 屆畢業(yè)設計 外文翻譯（英文） content, vapor gets easily absor