温度参数对升温型溴化锂吸收式热泵性能系数影响程度分析

通过对升温型溴化锂吸收式热泵进行理论分析,得到在相同工况条件下,发生温度变化对系统性能系数的影响程度最大,但小于吸收温度和冷凝温度影响程度之和.并利用焓浓度图,结合前人数据对理论分析进行了验证.     

吸收式热泵的分析

<正> 目前,世界上有大量的70～80℃之间的废热仍未开发利用,其它的低温热源,如太阳能、地热能也未充分利用。对这些低温热能,热泵是一种很有前途的利用手段,特别是吸收式热泵,由于利用了廉价的热能,在经济上优于压缩式热泵。在吸收式热泵能源利用系统的设计中。往往热泵本身是在最优状况下运行,但整个能源     

溴化锂吸收式热泵的研究及应用

主要探讨第I类和第Ⅱ类溴化锂吸收式热泵的性能,并从节能的角度分析了这两类热泵回收利用低温热源的经济性。     

LiBr／H2O高温吸收式热泵及其优化设计

一、前言 在石油、化工、纺织等工业装置中以废水、废汽等形式排放大量的余热,这不仅浪费了能源而且污染了环境。在世界节能技术的发展中,应用高温吸收式热泵节能已被广泛研究,它是近年来才发展起来的一种新型节能装置。高温吸收式热泵以消耗中温热能为补偿,提高余热的品位,使它能重新利用     

吸收式热泵技术的新发展

目前,电动的蒸汽压缩式制冷方式占据着主导地住.在我国,随着制冷和空调的迅速发展,不仅加剧了电力供应紧张的局面,而且面对着环境污染的严峻课题.本文综述我国溴化锂吸收式热泵技术发展概况,以及有关企业和地区推广应用溴化锂制冷技术于热电冷联产的情况,并作了能源利用和环境污染的分析,指出推广应用溴化锂制冷技术于热电冷联产是我国能源利用和制冷空调的一个发展方向.     

火电厂大型吸收式热泵溴化锂溶液进水后的提纯技术

介绍一种简单有效的热泵溴化锂溶液提纯装置及其使用方法,在实际生产中应用能够满足热泵溴化锂溶液浓度降低后的在线提纯,具有较高的实用性。研究成果在热泵出现泄漏状况时,不需要厂家专业人员,电厂运行维护人员可以自行进行提纯处理,保证安全生产高效、稳定。     

燃气吸收式热泵的应用探讨

一、前言随着能量消耗的增加和能源价格的上涨,节能技术越来越引起人们的高度重视,从而要求我们能更经济地使用能源。我们已经知道有一种制冷——供热系统,这种系统用来产生和维持低温,同时产生一定的热量,然而这部分被认为无用的热量从各个制冷系统中传     

溴化锂两级高温吸收式热泵及其设计

能源问题是各国都非常关注的问题,节约能源非常重要。一些工业过程排放出大量的气体、蒸汽或热水中含有大量的余热。它们的排放,不仅造成环境的污染,而且浪费了能源。回收其中的余热显得尤为重要。溴化锂两级高温吸收式热泵是一种热升温机,它能利用７０～１００℃余热本身驱动,生产１００～１６０℃的热水或蒸汽以供工业生产使用。文中介绍了两级溴化锂高温吸收式热泵的原理,对它的设计、性能等进行了分析,最后得出了结论。     

一种新型第二类吸收式热泵的原理及性能分析

提出一种包含吸收溶液冷却结晶过程的新型第二类吸收式热泵循环,并对其工作过程及性能特性进行理论分析与实验研究。结果表明,该循环可在吸收器吸收溶液质量分数显著高于发生器吸收溶液质量分数的条件下工作,其热泵温升能力明显优于现有AHT循环。当冷却结晶终温和冷凝器温度为35℃、发生器温度和蒸发器温度为92℃时,其热泵温升理论上可达97℃。     

Energy and exergy analysis of a double absorption heat transformer operating with water/lithium bromide

In the present study, the first and second law of thermodynamics have been used to analyze in detail the performance of a double absorption (lift) heat transformer operating with the water–lithium bromide mixture. A mathematical model was developed to estimate the coefficient of performance (COP), the exergy coefficient of performance (ECOP), the total exergy destruction in the system (Ψ_TD) and the exergy destruction (Ψ_D) in each one of the main components, as a function of the system temperatures, the efficiency of the economizer (EF_EC), the gross temperature lift and flow ratio (FR). The results showed that the generator is the component with the highest irreversibilities or exergy destruction contributing to about 40% of the total exergy destruction in the whole system, reason why this component should be carefully designed and optimized. The results also showed that the COP and ECOP increase with increase in the generator, the evaporator and the absorber–evaporator temperatures and decrease with the absorber and condenser temperatures. Finally, it was observed that the COP and ECOP are very dependent of the FR and the economizer efficiency (EF_EC) values. Also the optimum operating region of the analyzed system is shown in the present study. Copyright © 2009 John Wiley & Sons, Ltd.     

Lithium bromide high-temperature absorption heat pump: Coefficient of performance and exergetic efficiency

A theoretical study on the employment of a lithium bromide absorption heat pump in Spain, used as machine type I and aimed to produce heat at 120°C via waste heat sources at 60°C, is given in the paper. Real performance conditions are stated for each component of the machine, namely the absorber, the heat recoverer, the generator, the condenser, the solution pump, the expansion valve and the evaporator. By means of thermodynamic diagrams (p, t, x) and (h, x), the required data are obtained for calculation of the heat recovered in the evaporator Q_e, and the heat delivered to the absorber Q_a and to the condenser Q_c, as well as the heat supplied to the generator Q_g. In addition, the heat delivered by the hot solution to the cold solution in the heat recovered Q_r, and the work W_p done by the solution pump are calculated. The probable COP is calculated, and values are obtained close to 1.4. The working temperature in the generator is determined; it ranges from 178 to 200°C. The heat produced by the lithium bromide absorption heat pump is 22% cheaper than the heat obtained from a cogeneration system comprising natural gas internal combustion engine and a high temperature heat pump with mechanical compression. Compared with a high temperature heat pump with mechanical compression, the heat produced by the absorption heat pump is 31% cheaper. From (h, x) and (s, x) diagrams, exergy losses for each component can be determined, and, from these results, an exergetic efficiency of 75% is obtained, which provides the quality index of absorption cycle.     

Theoretical comparison of single stage and advanced absorption heat transformers operating with water/lithium bromide and water/Carrol mixtures

A thermodynamic analysis was carried out to compare the theoretical performance of single stage, two stage and double-absorption heat transformers operating with the water/lithium bromide and the water/Carrol mixtures, where Carrol is a mixture of lithium bromide and ethylene glycol [(CH₂OH)₂] in the ratio 1:4·5 by weight. A mathematical model to predict the theoretical performance of single stage and the advanced heat transformers is also described. Coefficients of performance and gross temperature lifts are compared for the different heat transformers and plotted against the main temperatures of the system for both mixtures. The water/Carrol mixture showed in general to have a better performance than the water/lithium bromide mixture. © 1998 John Wiley & Sons, Ltd.     

溴化锂吸收式制冷机采用塑料传热管的研究

提出了在溴化锂吸收式制冷机中采用塑料传热管代替铜传热管,以解决传热管腐蚀及其引起的冷量衰减问题。以1台制冷量为35kW的溴冷机为例,对采用塑料传热管的溴冷机与传统铜管溴冷机相关部件的参数进行比较。通过对溴冷机的传热面积、管道阻力的计算和安全强度的校核,发现采用塑料传热管的溴冷机在技术上是可行的。     

Experimental study of the use of additives in the performance of a single‐stage heat transformer operating with water–lithium bromide

In the present paper, the additives 1‐octanol and 2‐ethyl‐1‐hexanol, have been used for the first time in a 2 kW single‐stage heat transformer installed in the Energy Research Centre of the National University of Mexico utilizing H₂O/LiBr, operating at absorber temperatures in a range between 70 and 110°C. The results showed that at the same conditions, absorber temperatures increased about 5°C by adding 400 ppm of 2‐ethyl‐1‐hexanol to the lithium bromide mixture. Also it was shown that the coefficient of performance increases up to 40% with the same additive. Copyright © 2005 John Wiley & Sons, Ltd.     

Energy and exergy analysis of an experimental single‐stage heat transformer operating with the water/lithium bromide mixture

The first and second law of thermodynamics have been used to analyze the performance of an experimental single‐stage heat transformer operating with the water/lithium bromide mixture. Enthalpy coefficients of performance (COP), external coefficients of performance (COP_EXT), exergy coefficient of performance (ECOP), exergy destruction or irreversibility in the system and components (I) and the improvement potential (Pot) have been calculated against the gross temperature lift and the main operating temperatures of the system. The results showed that the highest COP, COP_EXT and ECOP values are obtained at the highest solution concentrations meanwhile the Pot and the I of the cycle remain almost constant against these parameters. Also it was shown that the COP, COP_EXT and ECOP decrease with an increase with the absorber temperature, meanwhile the Pot and the I increase. Moreover, it was observed that in all the cases independently of the operating temperatures of the system, the absorber accounts with most of the half of the total irreversibility in the system. Finally, it was shown that the improvement potential is considerable for the system. Copyright © 2009 John Wiley & Sons, Ltd.     

传热规律、热漏和内不可逆性对吸收式热泵循环性能的影响

建立了考虑泵热空间到环境热源的热漏、工质循环的内部不可逆性以及工质与热源之间传热Q∝△(T^a)服从传热规律时的不可逆四热源吸收式热泵循环模型,导出了循环泵热率和泵热系数的一般关系;并导出了线性唯象传热定律时循环泵热率和泵热系数的基本优化关系、性能极值、循环中工质的最佳工作温度和换热器传热面积的最佳分配关系;通过数值耸例分析了传热规律、热漏和内不可逆性对循环性能的影响规律,比较了传热面积最优分配前后循环的最优性能。     

Exergetic performance evaluation of heat pump systems having various heat sources

In this study heat pump systems having different heat sources were investigated experimentally. Solar‐assisted heat pump (SAHP), ground source heat pump (GSHP) and air source heat pump (ASHP) systems for domestic heating were tested. Additionally, their combination systems, such as solar‐assisted‐ground source heat pump (SAGSHP), solar‐assisted‐air source heat pump (SAASHP) and ground–air source heat pump (GSASHP) were tested. All the heat pump systems were designed and constructed in a test room with 60 m² floor area in Firat University, Elazig (38.41°N, 39.14°E), Turkey. In evaluating the efficiency of heat pump systems, the most commonly used measure is the energy or the first law efficiency, which is modified to a coefficient of performance for heat pump systems. However, for indicating the possibilities for thermodynamic improvement, inadequate energy analysis and exergy analysis are needed. This study presents an exergetic evaluation of SAHP, GSHP and ASHP and their combination systems. The exergy losses in each of the components of the heat pump systems are determined for average values of experimentally measured parameters. Exergy efficiency in each of the components of the heat pump systems is also determined to assess their performances. The coefficient of performance (COP) of the SAHP, GSHP and ASHP were obtained as 2.95, 2.44 and 2.33, whereas the exergy losses of the refrigerant subsystems were found to be 1.342, 1.705 and 1.942 kW, respectively. The COP of SAGSHP, SAASHP and GSASHP as multiple source heat pump systems were also determined to be 3.36, 2.90 and 2.14, whereas the exergy losses of the refrigerant subsystems were approximately 2.13, 2.996 and 3.113 kW, respectively. In addition, multiple source heat pump systems were compared with single source heat pump systems on the basis of the COP. Exergetic performance coefficient (EPC) is introduced and is applied to the heat pump systems having various heat sources. The results imply that the functional forms of the EPC and first law efficiency are different. Results show that Ex_loss,total becomes a minimum value when EPC has a maximum value. Copyright © 2008 John Wiley & Sons, Ltd.     

浅谈溴化锂吸收式制冷机的运转性能

本文详尽介绍了外界因素对溴化锂制冷机性能的影响状况 ,以精确的性能曲线图向读者展示了其运转性能特性