太阳能吸收式空调系统在别墅中的应用

根据别墅建筑的特点,建立一套太阳能与小型溴化锂吸收式制冷机相结合的制冷／热泵系统。该系统可为别墅建筑实现夏季制冷、冬季供暖以及全年提供生活用热水多项功能。介绍了整个系统的形式及其工作原理以及如何选择太阳能集热器和吸收式制冷机,并指出了系统的初投资较高、系统效率较低等不足;建议了提高制冷机制冷系数的措施以提高系统的总效率。     

太阳能吸收式空调

太阳能吸收式空调李军朱宁随着我国国民经济的高速发展和人民生活水平的不断提高，人们对生活环境舒适程度的要求越来越高，十年前被视为高消费的空调，如今已越来越成为办公乃至居住环境中必不可少的装置。常用的空调系统大致可分为两类：一类称为压缩式空调，另一类称为...     

太阳能吸收式制冷系统在呼和浩特地区应用的研究

采用当地小型太阳辐照气象站的实测数据,对该辐射条件下不同集热器的热性能进行试验对比,且对吸收式制冷系统进行了模拟计算。研究表明,集热器的高性能、当地的太阳能资源和冷却水温条件等是呼和浩特地区应用太阳能吸收制冷的保证。在文章所计算的条件下,系统总效率达0.473。文章的研究结果对呼和浩特地区大规模应用太阳能吸收制冷系统提供了理论依据。     

太阳能吸收式空调及供热综合系统

当前,世界各国都在加紧进行太阳能空调技术的研究。据调查,已经或正在建立太阳能空调系统的国家和地区有意大利、西班牙、德国、美国、日本、韩国、新加坡、香港等。这是由于发达国家的空调能耗在全年民用能耗中占有相当大的比重,利用太阳能驱动空调系统对节约常规能源、保护自然环境都具有十分重要的意义。为了进一步拓宽太阳能的应用范围,使其在节能和环保中发挥更大的作用,我国在“九五”期间开展了太阳能空调技术研究,旨在通过技术攻关和系统示范,解决太阳能空调中的技术难题,从而为尽早实现太阳能空调的商业化打下技术基础。一基本工作…     

太阳能吸收式空调系统集热面积的研究

分析了影响太阳能吸收式空调系统集热面积的因素;得出系统集热面积单耗的日逐时值;根据太阳能吸收式空调系统特点,提出了一种确定集热器集热面积的新方法,并以2级吸收式太阳能空调系统为例进行了详细阐述.分析结果表明,为减少集热面积,优化系统,须对太阳能空调系统增设蓄热装置.太阳能吸收式空调运行在8:00～18:00时,系统所需的最小集热面积单耗为1.085 m2/m2,其对应的蓄热器的容积单耗为0.036 3m3/m2,且随着太阳能空调运行时间的缩短,最小集热面积单耗减小,蓄热器容积单耗增加.     

太阳能吸收式热泵的优化

实际太阳能吸收式热泵运行在最大供热系数和最大供热率两种极限状况之间.本文导出两种太阳能收集器损失关系情况下,该热泵系统在上述两种极限状况下的最佳工作温度,为实际系统的参数选择提供了理论依据.     

太阳能吸收式与吸附式制冷技术的比较与发展

通过对太阳能吸收式和吸附式制冷的工作原理、制冷工质对、结构和多效/多床系统的综合分析比较,对提高以上2种系统COP的方法及将来的发展趋势进行了阐述。结果表明:除了使用混合溶液为工质对和聚合集热器之外,运用多效和多床系统也可以很好地提升其制冷的效率。     

太阳能吸收式空调及供热系统的设计和性能

一套太阳能吸收式空调及供热综合系统已在山东省乳山市建成。该系统由热管式真空管集热器、溴化锂吸收式制冷机、储水箱、循环、冷却塔、空调箱、辅助燃油锅炉和自动控制系统等内部分组成,具有夏季制冷、冬季供热和全年提供生活用热水等功能。太阳能集热器总采光面积540m∧2,制冷、供热功率100kW,空调、采暖建筑面积1000m∧2供生活用热水量32m∧3／d。文中着重介绍了系统的设计特点和测试性能。     

Cost effective asymmetric CPC solar collectors

Low cost CPC solar collectors were designed, constructed and tested. The collectors consist of two separate absorbers, which are horizontally incorporated in a stationary asymmetric CPC mirror. The efficient operation of the proposed collectors is due to the direct absorption of a large part of the incoming solar radiation and to the thermal losses suppression by the inverted surface of both absorbers. Two collector types with the same basic design are presented. The first type has tubular absorbers which are used for direct water heating and the second has flat fin type absorbers with pipe. Test results showed that the proposed collectors operate efficiently and are suitable for hot water applications.     

CPC在太阳能集热器中的应用

CPC复合抛物聚光器是一种非成像低聚焦度的聚光器,它根据边缘光线原理设计,可将给定接收角范围内的入射光线按理想聚光比收集到接收器上。由于它有较大的接收角,故在运行时不需要连续跟踪太阳,只须根据接收角的大小和收集阳光的小时数,每年定期调整倾角若干次就可有效的工作。它可达到的聚光比在10以内,当聚光比在2以下时可做成固定式装置。它可接收直射太阳辐射和部分散射辐射,并能接收一般跟踪聚光器所不能接收的“太阳周围辐射”。此类集热器的结构比较简单,对聚光面型加工精度要求不严格,将其应用在太阳能集热器中,是一个值…     

A comparison of solar absorption air conditioning systems

A computer simulation of solar powered absorption air conditioning systems is discussed. The results of simulations of various systems composed of conventional flat plate or evacuated tube collectors, wet or dry cooling towers, lithium bromide-water or aqua-ammonia working fluids and hot water, chilled water or refrigerant storage alternatives are obtained over a common operating cycle. Performance of the lithium bromide-water working fluid is shown to be superior to aqua-ammonia. Relative performance gains realized with the evacuated tube collector and relative performance losses associated with the dry cooling tower are presented. Chilled water storage is shown to be advantageous for an evacuated collector, dry cooling tower, lithium bromide-water system.     

Investigation on feasibility of ionic liquids used in solar liquid desiccant air conditioning system

The corrosion problem of traditional liquid desiccants hinders the development of solar liquid desiccant air conditioning system. Ionic liquids (ILs) could be a possible substitute because of their low corrosion to metals. According to the characteristic of cation and anion, two ILs 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄) and 1,3-dimethylimidazolium acetate ([Dmim]OAc) were selected for possibility investigation. The experimental results demonstrated that the surface vapor pressure of [Bmim]BF₄ aqueous solution was so high that it was not suitable for dehumidification. With comparing the structure of [Bmim]BF₄ and 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF₄), it was found that for imidazole salts with the same anion, as the alkyl chain of the cation becomes shorter, the surface vapor pressure of its aqueous solution would be lower. In addition, simulation model was used to compare the dehumidification performance of [Dmim]OAc and [Emim]BF₄ with that of the traditional desiccants lithium Chloride (LiCl) and lithium bromide (LiBr). The results showed that in the same condition, [Dmim]OAc with an inlet mass concentration of 81.7% and [Emim]BF₄ of 85.5% could reach the same dehumidification rate as LiCl of 40.9% and LiBr of 45.0% mass concentration. Better dehumidification performance of [Dmim]OAc than that of [Emim]BF₄ was achieved, thus, like [Emim]BF₄, [Dmim]OAc can also be a promising substitute for traditional desiccant.     

Comparative study of air heating solar collectors

Three types of conventional solar air heater are designed such that their heat absorbing areas and the pressure drops across them are equal for equal air mass flow rates per unit collector area. The results of thermal performance tests conducted simultaneously on these collectors, under the same environmental conditions, are presented.     

Residential air conditioning and heating by means of enhanced solar collectors coupled to an adsorption system

This work explores the possibility to perform heating and air-conditioning of state of the art building located near Paris in France. For air-conditioning, enhanced compound parabolic solar collectors are used as a heat source of an adsorption system (methanol/activated carbon), while during winter direct coupling with the building is performed.A model describing the adsorption unit, the solar collectors and the house was used to simulate the performances of such an installation.For air-conditioning, thermal comfort is achieved as indoor temperature is kept below 25 °C during five consecutive hot days (heat wave effect), contrarily to the case for which only free-cooling during nighttime is used. For heating, the indoor temperature remains below the comfort temperature value by 2 K. Nevertheless, the auxiliary heating need will remain limited so that savings on electricity or fossil fuel consumption will be possible.     

太阳能热发电系列文章(14)CPC在太阳能热利用中的应用

综述了CPC聚光器的光学原理、制作方法、优点和在太阳能领域的应用;分析了CPC由倒V型结构向W型结构发展的原因;阐述并提出了直通式CPC、热管式CPC、自聚光式CPC的结构和优点;设计了多种双层玻璃管式CPC结构。     

太阳能热发电系列文章(15)太阳能热发电中的聚光器

分析了聚光器的设计要求和聚光器种类;介绍了现有聚光器的现状,并进行了分析比较,说明了其发展趋势;阐述了我们在这方面所做的工作。     

Optimum tilt angle for solar collectors used in Cyprus

Flat-plate solar collectors are widely used in Cyprus for water heating purposes. The roofs of nearly all the residential premises on the island are fitted with such collectors. This article examines the theoretical aspects of choosing a tilt angle for the solar flat-plate collectors used in Cyprus and makes recommendations on how the collected energy can be increased by varying the tilt angle. In this paper, the collector surface is assumed to be facing South and the calculations are based upon the measured values of daily global solar radiation on a horizontal surface on the island. The beam and diffuse components of the horizontal global radiation are then estimated and the solar radiation on a tilted surface is calculated as the angle of tilt is varied from 0° to 90°. It is shown that very nearly optimal energy can be collected if the angle of tilt is varied seasonally, four times a year.     

Solar absorption air conditioning alternatives

The relative advantages of a single-stage, lithium bromide-water absorption air conditioner heated from a flat-plate solar collector are compared theoretically to those for an ammonia-water system, and the lithium bromide system is selected as the preferred one. Double-stage absorption systems with their improved performance are described and are shown theoretically to require generator temperatures that are too great to make them attractive for use with flat-plate collectors. Dual, series-connected systems which require no cooling tower for heat rejection are shown by analysis to have a low coefficient of performance. Systems utilizing refrigerant storage and a heat rejection buffer between a cooling tower and the absorber and condenser are discussed along with the computer simulation describing them. They are shown to require smaller cooling towers than conventional units. Operation with an air heat exchanger rather than the cooling tower in such a system is shown to yield acceptable system performance with a small reduction in the fraction of the cooling load which can be met with solar energy.