开发溴化锂吸收式制冷机回收工业余热

一、问题的提出在我国能源消耗中,据1990年统计,工业耗能占68.9%,总耗能约为6.8亿吨标煤.工业余热资源量很大,回收利用工业余热是一项重要的节能及环境保护措施.但对于温度较低范围的等热回收则显得非常困难.如化学工业和石化工业中,温度在120℃左右的余热;在钢铁工业中低于150℃左右的余热.如何充分地回收     

溴化锂吸收式制冷机与蒸汽压缩式制冷机的能耗比较

本文对溴化锂吸收式制冷机与蒸汽压缩式制冷机的能耗进行了比较研究,认为溴化锂吸收式制冷机节电不节能,而溴化锂吸收式制冷机与离心式制冷机联合运行,既可缓解供电紧张,又可提高能量利用效率,应予以充分重视。     

大力推广吸收式制冷机 发展热电冷联合生产

一、蓬勃发展的制冷空调市场随着改革开放的不断扩大和深入,我国国民经济生产总值增长迅速,人民生活水平也有着大幅度提高,过去主要只用于食品冷库冷藏、化工、制药、纺织等领域的制冷行业近些年来得到了特别迅猛的发展,除了电冰箱之外,食品冷期藏链的其它各个环节和空调器的应用与发展也突飞猛进。尤其是空调装置,已成为现代化的标志之一,成为新的消费热点,全国制冷空调所耗电能已占全国年发电量的相当份额。近年来国家年发电装机容量虽以8000～     

溴化锂吸收式制冷机的节能途径

本文介绍了溴化锂吸收式制冷机的组成及影响能耗因素,提出了多种节能途径。     

溴化锂吸收式制冷机的应用分析

概述了溴化锂吸收式制冷的原理，分析了溴化锂吸收式制冷机的综合效益及其一次能源利用率，以热电厂热电冷三联供系统为例分析了溴化锂吸收式制冷机的节能效益，并指出了溴化锂吸收式制冷机在工程应用中应注意的问题。     

吸收式制冷机在船舶上应用的技术经济分析

从节能和环保要求的角度出发,阐述和分析了吸收式制冷应用于远洋船舶的可行性和经济性,采用一次能源利用系数作为性能指标,对压缩制冷和吸收式制冷进行一次能源利用水平分析,并对不同制冷方式进行成本核算,从而进行技术经济评价。     

蒸汽双效溴化锂吸收式制冷机的新流程

针对目前国产蒸汽双效溴化锂吸收式制冷机体积大、性能系数（ＣＯＰ）低、铜材耗量多、制造成本高的特点,在认真分析传统蒸汽双效溴化锂吸收式制冷机流程的基础上,经过大量对比计算,提出了两种新溶液循环流程系统,新循环流程方案与传统流程方案相比,传热面积可大大减小,性能系数（ＣＯＰ）可大幅度提高,不但能降低制造成本,还可节省运行费用。     

Effect of storage tanks on solar-powered absorption chiller cooling system performance

Thermal storage, low power tariff at night, and low nocturnal temperature can be used in synergy to reduce the cooling costs of the solar-powered absorption chiller cooling systems. This study aims to reduce the required cooling capacity of an absorption chiller (ACH) powered by a solar parabolic trough collector (PTC) and a backup fuel boiler by integrating thermal storage tanks. The thermal performance of the system is simulated for a building that is cooled for 14 h/day. The system uses 1000 m² PTC with 1020 kW ACH. Chilled water storage (CHWS) and cooling water storage (CWS) effects on the system performance for different operation hours per day of the ACH under Izmir (Turkey) and Phoenix (USA) weather conditions are analyzed. When the ACH operates 14 h/day as the load for both systems and both locations, the variations of the solar collector efficiency and the cooling load to heat input ratio remain less than 4% after the modifications. From the addition of CHWS to the reference system, a parametric study consisting of changing the ACH operation hours per day shows that the required cooling capacity of the ACH can be reduced to 34%. The capacity factor of the ACH is improved from its reference value of 41% up to 96%.     

Off grid diesel engine-based trigeneration systems with thermal storage and compression chiller for enhanced performance

The paper proposes a diesel engine-based trigeneration system using a thermal storage for applications with simultaneous heating, cooling and power demand and where grid electricity is not available. A thermodynamic analysis is presented for the proposed trigeneration systems considering an 815?kWe diesel generator (DG) as a prime mover. Two configurations are considered. One configuration includes absorption chiller with an auxiliary hot water heater, while the other has a compression chiller in addition to the absorption chiller and water heater. Methodology of integrating a compression chiller is also presented. An analysis of both these options on primary energy savings basis for the considered DG shows that integrating a thermal storage and compression chiller enhances trigeneration performance. Without the compression chiller, the trigeneration system efficiency improves from 46% to 52% while with compression chiller integration, the improvement is much more from 46% to 72% when the power load decreases from 100% to 25%.     

Proposal of a hybrid CHP system: SOFC/microturbine/absorption chiller

Distributed generation is becoming an attractive option for industrial and commercial scale customers. The main advantage of this on‐site power generation is that it offers a more efficient, reliable and cost‐effective power supply. In addition, waste heat can be used for local heating or cooling. This is known as cogeneration or combined heat and power (CHP). In the present work, a hybrid‐CHP system for a 230 kWe demand building is proposed and analyzed. The system considers the coupling of:

• A Solid Oxide Fuel Cell stack with an output of 200 kWe
• A Microturbine with an output of 30 kWe
• A single effect Absorption cooling system providing 55 kWt for air conditioning using water chillers

This plant would use natural gas as the primary fuel. The SOFC module is fed with the gas fuel and the whole stack generates the main power while acting as a combustor. The product gases exit the anode at a temperature of 900°C and are directly injected to the Micro Gas Turbine unit to produce additional power. Finally, the waste heat available at the turbine's exhaust fires a single effect Absorption Water‐Chiller to provide cooling for air conditioning in the building. This proposed system would generate up to 230 kWe and 55 kWt with high thermal efficiencies of around 70–75%. Currently, Hybrid SOFC/GT and Microturbine/CHP systems are being considered or tested at several facilities. However, a combination of both, which would yield to trigeneration, has not been considered yet. Here we present a conceptual model based on specific proposals and investigations done by other researchers. A theoretical analysis on the proposed model is conducted to evaluate the potential and possibilities of such Hybrid CHP system and further discussions based on the economical considerations is also presented. Copyright © 2009 John Wiley & Sons, Ltd.     

Steam absorption into films of aqueous solution of LiBr flowing over multiple horizontal pipes

The absorbers of absorption chillers consist of horizontal tube banks, over the outer surfaces of which absorbent flows and inside of which cooling water runs. The dependence of the distribution of absorption rate on the position of the pipes is important but has not been studied previously. In this paper, the cases of one to three pipes are studied experimentally in the range of film Reynolds numbers between 5 and 40. Three different surfaces are tested to study the effect of wettability. Numerical calculations are also performed using the method proposed in our previous paper. The highest absorption rates are obtained for the pipes with higher knurls, and their distributions agree with the numerical predictions. The pipe position which shows the maximum absorption rate varies with flow rate but the maximum absorption rate does not vary greatly with flow rate. The heat transfer coefficient is minimum and almost constant with flow rate at the top pipe. At lower pipes it becomes larger, but tends to decrease with increasing flow rate. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(7): 476–485, 1996     

Steam absorption into films of aqueous solution of lithium bromide and lithium iodide mixture falling over a column of horizontal pipes

To improve absorption chiller performance, an aqueous solution of lithium bromide and lithium iodide mixture at the ratio of 1:0.7 was proposed for an absorbing medium since it has a higher solution limit than conventional lithium bromide solution. But the component lithium iodide solution has a higher equilibrium pressure than the lithium bromide solution. To investigate the absorption performance of the mixture liquid, experiments were carried out using a horizontal pipe column. Experimental range of the mass concentration was 62–66% for the mixture solution and 62–63% for the lithium bromide solution. The absorption rate of lithium bromide solution at 62% and 63% is almost equal to the mixture solution at 63% and 64%, respectively. Compared at the same concentrations, the mixture solution is inferior to the lithium bromide solution; at the maximum concentration, the mixture solution has about 20 to 50% higher absorption rates than the lithium bromide solution. Surface temperature of the falling films was measured by thermal video and used to determine the heat transfer coefficient and mass transfer coefficient, which becomes larger for the mixture solution than for the lithium bromide solution. This is due to the decreased viscosity of the mixture solution. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(7): 431–444, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20213     

Steam absorption process of water/LiBr system inside vertical small bore pipes

In a previous paper, a numerical model for absorption within vertical pipes was proposed and compared with the experiments. Agreements were good for pipes with an OD 28–15 mm but at 10 mm pipe experiments fell below the predicted values. For smaller diameters, the difference between the surface area of the falling liquid film and that of the outer surface of the pipe is not negligible and the thickness of the liquid film is also not negligible. In this paper a new model is formulated in cylindrical coordinates and experiments using pipes with 9.52 mm and 7 mm OD are done. Smooth pipes and two kinds of internally finned pipes, originally developed and used to enhance the heat transfer characteristics of the evaporator and condenser of a refrigerator using HFC as refrigerant, are tested in the experiments. The absorption performance is enhanced by 30% when compared to the smooth pipes, but the difference between the finned pipes is small. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(1): 18–28, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20040     

Steam absorption into aqueous lithium bromide solution films falling inside vertical pipes

The realization of a compact and efficient air‐cooled absorber is the key technology for the small‐capacity absorption refrigerator for domestic use. A vertical pipe with absorbent flowing inside and air flowing outside is the best choice for the air‐cooled absorber due to the easy addition of fins to enhance heat transfer on the air side. In this paper, first, the modeling of the absorption process in the vertical pipe for a constant heat transfer coefficient on the outer surface is described. Then, experimental results are presented for pipes of inner diameters 8 to 26 mm, pressure 5 and 6 mm Hg, and outer surface heat transfer coefficient 2000 and 3300W/(m²·K). It was found that for pipes of diameter 13 mm or more, the absorption process is well estimated by the proposed model. The absorption with addition of surfactant is estimated by the pseudo‐turbulent method. The necessary heat transfer area for the air‐cooled condition is about three times that for the water‐cooled condition. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 740–752, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10128     

On-site real-time evaluation of an air-conditioning direct-fired double-effect absorption chiller

This work presents a procedure for calculating the COP and heat transfer rates, based on on-site experimental temperature measurements, of a lithium–bromide/water direct-fired double-effect absorption chiller in reverse parallel flow configuration, running on natural gas. The chiller was equipped with a set of thermocouples which allowed measuring its working temperature levels through all its operating stages. The chiller analysed in this work is the central cooling system of the air-conditioning installation of the Principe Felipe Science Museum, located at the Valencia’s City of Arts and Sciences (Spain). This installation is capable of providing a cooling capacity of 4.5 millions of kcal/h (5.2 MW), by means of three direct-fired double-effect absorption chillers. From the experimental measurements a calculation procedure, based on energy and mass balances, has been developed, which allows estimating the specific powers by unit of mass flow rate through the evaporator. From these power values the instantaneous COP of the chiller could be obtained. Additionally, the paper analyzes different aspects that were not possible to be considered and details the actions taken in order to take them into account.     

Experimental research on dynamic operating characteristics of a novel silica gel-water adsorption chiller

A novel silica gel-water adsorption chiller consisting of two adsorption/desorption chambers and an evaporator with one heat-pipe working chamber is experimentally studied. The dynamic operating characteristics of the chiller and the thermodynamic characteristics of the adsorber are obtained. The experimental results show that the dynamic operating characteristics of the chiller and the thermodynamic characteristics of the adsorber are satisfactory and that the cycle is a novel and effective adsorption cycle. A mass recovery process increases the cyclic adsorption capacity of the system and improves adaptability of the chiller to a low-grade heat source. In addition, the experiment indicates that this novel chiller is highly suitable for an air conditioning system with a low dehumidification requirement or a system with a large cycle flowrate and an industrial cooling water system. Translated from Journal of Shanghai Jiaotong University, 2006, 40(2): 306–310 [译自: 上海交通大学学报]     

Steam absorption into films of lithium bromide solution falling over horizontal pipes arranged in a vertical column

Absorber of a water/LiBr absorption chiller is made up of horizontal tube banks, and its improvement is needed to get higher COP. To clarify the absorption process in these tube banks, a single row of horizontal pipe column is studied experimentally and analytically. The analytical model proposed in a previous paper is further changed to a conservative form according to the method of Shyy. It is confirmed that the mass balance of water is kept exactly by the present procedure. As for total absorption rate for the pipe column, the agreement between experiment and numerical calculations is fairly good except for the cases of 8 to 10 pipes at a lower flow rate. The roughed pipes with different knurls on their surface were also tested experimentally and it was found that a knurl height of 0.5 mm was the most effective in absorption enhancement. © 2001 Scripta Technica, Heat Trans Asian Res, 30(6): 451–462, 2001