小型太阳能海水淡化装置

基于空气增湿-除湿海水淡化技术,采用热海水与空气逆流对喷的空气加湿器,设计了结合太阳能集热器的小型太阳能海水淡化系统。试验结果表明,该结构的空气加湿器具有很好的加湿效果,出口空气相对湿度可达到98%以上。当喷水温度为60℃、空气流量为11.8 L/s时,该小型海水淡化装置产水率可达3.42 kg/h。     

多效增湿除湿太阳能海水淡化装置的性能试验

文章提出了一种具有规模灵活、操作简单、维护运行成本低廉、易于和可再生能源结合等优点的新型多效增湿除湿太阳能海水淡化装置;介绍了装置的结构和运行原理,进行了海水运行温度、进水流量等影响产水性能的参数的实验研究。研究结果表明,装置产水量随进水流量和运行温度增加而增大,当进水流量为906 kg/h时,装置产水量达到58.14 kg/h。该多效增湿除湿海水淡化系统具有较大的性能提升空间和广阔的应用前景。     

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...     

一种新型太阳能海水淡化系统的实验研究

介绍了一种新型的太阳能海水淡化方法,即结合太阳能空气集热器和太阳能热管、利用空气增湿除湿来实现海水淡化。分别进行了电吹风模拟太阳能空气集热器的蒸发器实验,以及结合3m2太阳能空气集热器和热管集热器的实际装置实验。结果表明,影响蒸发量的主要因素为热空气温度、热空气流量、初始水量、水温、出气孔直径和数量。实验结果表明,装置可获得的最大冷凝量为790g/h,计算出系统的产水率和热力学效率分别为5.59×10-5kg/kJ和12.4%。     

太阳能吸收式制冷空调集热器的研究

介绍了用于太阳能吸收式制冷空调的各种集热器,根据它们的应用情况分析了太阳能吸收式制冷空调的发展趋势及对集热器的要求,并提出了CPC热管式真空管集热装置,对其进行了研究和展望.     

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.     

太阳能吸收式空调系统的经济性分析

针对一个特定的对象,进行了太阳能吸收式空调系统寿命周期内的模拟计算及影响因素的分析,结果表明：（1）单纯太阳能空调（无采暖与热水供应）的经济性很差,太阳能空调与供热的复合系统的经济性要优于单纯的太阳能空调系统;（2）太阳能采暖与空调的复合系统,采暖与供冷的负荷比对系统的经济性有很大影响,即使在最佳的负荷比时仍无法和常规的系统竞争;（3）太阳能与生活热水系统的负荷系统中,热水负荷所占比重越大,经济性越好,当太阳能空调使用生活热水系统夏季多余的热量时,太阳能空调系统经济上可以和天然气锅炉＋电动制冷机竞争,并具有很好的节能性和环境效益。     

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。     

多级增湿太阳能海水淡化的实验研究

基于多级增湿和分级冷凝原理,设计搭建了一台新型利用太阳能的多级增湿海水淡化装置,实验研究了喷水温度、不同的空气循环方式、分级冷凝对系统产水率和热耗的影响变化规律。研究结果表明,由于采用了分级冷凝和多级增湿技术,系统产水率提高了25%～50%,产水热耗得以降低。     

吊顶辐射冷却塔供冷系统试验研究与性能分析

通过供冷试验及TRNSYS软件模拟研究了吊顶辐射冷却塔供冷系统的运行效果,分析了气象参数、部件结构等因素对系统供冷效果的影响,并与常规供冷系统全年的运行能耗进行对比。试验与理论分析结果表明,吊顶辐射冷却塔供冷系统的有效供冷量能够满足用户供冷需要,供冷房间温度稳定且分布均匀。冷却塔供冷效果与大气湿球温度、建筑内部负荷、热交换器结构等因素有关。辐射顶板末端与冷却塔供冷匹配性高,系统全年运行时数增加,应用于需全年供冷的建筑节能效果显著。     

Experimental performance of a thermoelectric ceiling cooling panel

An experiment has been performed to investigate the cooling performance of a thermoelectric ceiling cooling panel (TE‐CCP). The TE‐CCP was composed of 36 TE modules. The cold side of the TE modules was fixed to an aluminum ceiling panel to cool a test chamber of 4.5 m³ volume, while a copper heat exchanger with circulating cooling water at the hot side of the TE modules was used for heat release. Tests were conducted using various system parameters. It was found that the cooling performance of the system depended on the electrical supply, cooling water temperature and flow rate through the heat exchanger. A suitable condition occurred at 1.5 A of current flow with a corresponding cooling capacity of 289.4 W which gives the coefficient of performance (COP) of 0.75 with an average indoor temperature of 27°C. Using thermal comfort test data in literature for small air movements under radiant cooling ceilings, results from the experiments show that thermal comfort could be obtained with the TE‐CCP system. Copyright © 2007 John Wiley & Sons, Ltd.     

顶板冷辐射加置换通风空调系统评价分析

介绍了顶板冷辐射与置换通风相结合的空调系统特点,分析了该系统在改善室内空气品质和满足人体的热舒适性方面的特点,评价了该系统的节能效果和经济性。     

Parametric analysis of space cooling systems based on night ceiling cooling with PCM‐embedded piping

A parametric analysis is conducted for space cooling systems based on cold water flowing, during the night, within regularly arranged pipes embedded in a layer of phase change material (PCM), located among the structural layers of the ceiling. The introduced PCM layer in conjunction with night cooling add to the usual ceiling cooling systems offers the advantages of low energy consumption, high cool storage capacity, operation under reduced night electricity price, smoothing of electricity consumption by eliminating daily peak loads, improved thermal comfort and elimination of ceiling dripping. Our parametric analysis is based on a transient three‐dimensional finite‐difference solution of the related heat‐transfer problem for various values of all the main system parameters. PCM phase change process is simulated by using the effective thermal capacity function, which is determined experimentally for PCM suitable for air‐conditioning applications. Our tests showed that the main parameters of the system are pipe spacing, PCM layer thickness, pipe depth within the ceiling, cooling water inlet temperature, night cooling duration and PCM properties (thermal conductivity, phase change heat and ends of phase change temperature range). The effect of all the above parameters is analysed and suggestions are made for selecting the proper combinations of their values in order to obtain the lowest energy consumption in conjunction with the highest level of thermal comfort. Copyright © 2010 John Wiley & Sons, Ltd.     

A new type of cooling ceiling panel with corrugated surface—Experimental investigation

In this paper a new type of cooling ceiling panel with corrugated surface has been studied experimentally. A heat flux and a heat transfer coefficient for the new type panel were compared with the reference values obtained for a panel of a flat surface. It was shown that increase of the new panel cooling performance results both from increase of its area and from enhancement of natural convection heat transfer. For typical operation conditions, the increase of the new type panel cooling capacity varies from 26 to 55%, in comparison with the reference panel. In addition, the new type panel is more resistant to the risk of dew point and enables the achievement of higher EER values by the heat pump cooperating with it.     

Experimental results of a solar absorption cooling plant in Greece

Over the last years, the thermal comfort level during the summer period has been significantly increased due to the use of conventional cooling and air-conditioning systems, leading to higher electricity consumption. Solar cooling systems may provide the solution and become the leading technology in the future. The aim of this paper is to present a small-scale solar thermal system for cooling an office building in Athens, Greece. The study documents the system design, the monitoring procedure and equipment, and presents the experimental results from the first complete summer period. The daily electrical coefficient of performance (COP) of the absorption chiller of 48.6 and the electrical COP of the solar system 10.9 indicate the potential of solar cooling in small-scale systems.     

Numerical analysis of temperature non-uniformity and cooling capacity for capillary ceiling radiant cooling panel

Capillary ceiling radiant cooling panel is a high temperature cooling system, which could pose low energy consumption to meet thermal comfort requirements. A computational fluid dynamics (CFD) simulation study on heat transfer of chilled water flow in the capillary of ceiling radiant cooling panel was performed to attain surface temperature distributions and cooling capacities. Six influencing factors included chilled water inlet parameters, conditions of gypsum plaster and capillary mats structural parameters were considered to obtain the complicated relationships between capillary radiant panel conditions and heat transfer performance. The index of temperature non-uniformity coefficient was proposed to evaluate temperature profiles of ceiling panel surface. The results of the simulation were compared with the values depicted in ASHRAE Handbook and good agreement had been achieved. The average difference between simulation results and the values reported by ASHRAE handbook was within the region of 15%. The research results showed that temperature non-uniformity coefficient was negatively correlated with temperature of chilled inlet water (linear correlation), water velocity (correlation coefficient R = −0.85), and pipe diameter (correlation coefficient R = −0.93), but positively and linearly correlated with tube spacing. Cooling capacity was found to have negative linear correlation with temperature of chilled inlet water, covering thickness and tube spacing.     

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%.     

On the parasitic power of solar absorption cooling systems and criteria for operational control

This paper investigates the amount of electrical power required, on top of thermal energy needs, in order to generate and deliver the cooling effect of solar absorption cooling systems as compared with the electrical power needs of equivalent vapour compression cooling systems. Further, the effects of degraded operating temperatures and partial load conditions on the power cost per unit of cooling effect in both systems are investigated. It is shown that, under unfavourable conditions, power cost in both systems will be equal. This condition is attained when the two equivalent systems operate at about one-third of their design cooling capacity. It is argued that electrical power saving with solar absorption systems would be improved if a multi-unit configuration is used instead of single unit configuration.     

Thermal characteristics of a volumetric solar absorption system

Solar volumetric heating is one of the alternative clean energy applications, and the improvement of thermal storage capacity of the system is necessary for the efficient applications. Consequently, volumetric solar absorption flow system incorporating the absorber plate in the channel was investigated for different Reynolds numbers and solar concentrations. The influence of the location of the absorbing plate on the heat transfer and hydrodynamic losses was also examined in the channel. In order to increase the thermal storage capacity of the working fluid, phase change materials of 7% concentration was incorporated in the analysis. Lauric acid was used as phase change materials, and water was considered as the carrier fluid in the channel. The performance and pump power loss parameters were introduced to assess the thermal performance of the volumetric solar absorption system. It is found that the performance parameter attained the highest value for the absorber plate location at the top of the channel, which was about 10% higher than those corresponding to the other locations. This was more pronounced with increasing Reynolds number and solar concentration. The pump power loss parameter was the highest for the absorber plate location at the mid‐height of the channel. Copyright © 2013 John Wiley & Sons, Ltd.