相变蓄冷技术在公共建筑太阳能空调系统中的应用研究

为提高公共建筑太阳能空调系统的太阳能保证率,在传统太阳能空调蓄冷系统的基础上,将相变蓄冷技术应用在公共建筑太阳能空调系统中,并建立相应的数学模型。经软件模拟和实验测试,表明太阳能空调相变蓄冷系统数学模拟与实测数据吻合较好,验证了太阳能空调相变蓄冷系统的可行性和有效性。在该文案例中,与传统水蓄冷系统相比,相变蓄冷系统可使系统制冷季太阳能保证率提高17.5%。     

基于溶液除湿的风冷热泵系统性能分析

为了克服利用冷却除湿的风冷热泵空调系统机器露点过低、需要再冷和过热、难以适应显热潜热比例的变化、不能蓄能等缺点,提出基于集热再生器溶液除湿的热泵空调系统。通过济南某工程实例研究表明,与冷却除湿空调系统相比较耗电量减少12.3%,利用太阳能加热溶液除湿具有降低空调除湿能耗、利用可再生能源、减少高品位能源消耗等优势。证明太阳能溶液除湿在空调系统中是处理潜热负荷的理想选择,具有较好的节能性。     

光伏直驱冰蓄冷空调系统性能分析

为克服太阳能空调间隙性制冷,解决长时间稳定供冷问题,搭建一种光伏直驱冰蓄冷空调系统。针对系统在不同工况下运行稳定性以及不同工作模式下蓄冷供冷特性进行实验研究。实验表明,系统采用19 m~2光伏组件,保障系统稳定运行的辐照度下限为148 W/m~2。系统采用制冰蓄冷后融冰供冷模式运行,制冷系统额定输入电功率为2.2 kW,制冰量为165 kg,COP为0.23。研究发现,制冰蓄冷过程中系统COP随蒸发器表面冰层厚度的增加而减少,因此优化系统运行模式为制冰蓄冷并同时融冰供冷模式,COP达到0.36,较优化前提升56%。     

太阳能液体除湿空调系统中除湿器型式的选择

太阳能液体除湿空调系统是一种利用太阳能等低温热源的节能空调系统。除湿器直接影响太阳能液体除湿空调系统的性能。本文从焓湿图、蓄能、MR的选取和除湿效果等几个方面对目前被广泛应用的两种典型的除湿器进行了比较分析。     

冰蓄冷空调的应用及经济分析

本文阐述了蓄冷空调的国内外发展情况，介绍了几种常见冰蓄冷空调系统的运行模式，并以某工程为例对冰蓄冷空调系统的经济性进行了分析。     

太阳能制冷讲座(8) 太阳能溶液除湿空调(上)

介绍了太阳能溶液除湿空调的工作原理及特点。详述了系统主要部件除湿器、太阳能集热再生器的构成,介绍了太阳能溶液蓄能原理,并对太阳能溶液除湿空调的研究进展和应用前景进行了总结。     

发展蓄冷空调技术、推动电网移峰填谷

本文简要说明了电力用户需求侧采用蓄冷空调技术进行移峰填谷的必要性和我国目前蓄冷空调发展现状。介绍了蓄冷空调的工作原理和工作模式，以实例分析了蓄冷空调和常规空调的经济性，并提出了推广电蓄能技术的措施。     

太阳能溶液除湿空调(下)

五太阳能溶液蓄能太阳能是分布广泛、使用清洁的可再生能源,但太阳辐射的不连续性和不稳定性,成为太阳能利用的关键问题。太阳能溶液除湿空调系统可吸收太阳能,并以空调能力的形式储存于除湿剂浓溶液中,是一种有效的蓄能方式。太阳能溶液除湿空调循环中,浓溶液在除湿     

太阳能液体除湿空调系统再生和蓄能特性的研究

太阳能液体除湿空调系统中,能量在液体除湿剂中以化学能的形式存在,蓄能潜力大,再生温度低,可以利用太阳能或其它低位余热和废热。着重分析了液体除湿空调系统中溶液的再生原理和再生过程的传热传质特性,对再生过程进行了实验研究,获得了再生过程对流传质和对流换热的实验准则方程,讨论了各主要因素对再生量的影响。对再生器的蓄能特性进行了分析,讨论了太阳能液体除湿空调系统蓄能工况的运行方式。     

蓄冷空调系统运行评价方法研究及影响因素分析

通过对现有蓄冷空调系统运行过程中能耗和经济性评价方法的分析,为了更好的、全面的评价蓄冷空调系统运行过程中的能耗经济性,提出用单位冷量能效经济系数评价蓄冷空调系统运行过程中能效性和经济性,并对影响蓄冷空调系统运行过程中单位冷量能效经济系数变化的因素进行了初步的分析。     

转轮式固体干燥剂制冷空调系统的数值计算与分析

阐述了一种新型制冷空调机－转轮式固体干燥剂制冷空调系统的组成及其原理，并建立了物理模型和数学模型。在此基础上用编制的ＤＡＣＳ程序，对一种通风式系统的性能进行了计算。     

蓄能型液体除湿蒸发冷却系统中除湿性能的实验研究

提出了一种新型空调系统——液体除湿冷却空调系统的设计方案并搭建一功率为3kW的实验台，考虑到除湿过程和再生过程是该系统性能优良的决定性环节，设计加工了水冷型波纹板降膜式结构的除湿器和以丝网填料作为内部填料的再生器。在此实验装置上对系统的除湿过程以及其蓄能能力特性进行了实验研究，得出影响该系统除湿能力、蓄能能力等方面的主要因素，为系统的优化设计和运行提供依据。     

Experimental investigation of a liquid desiccant system for solar cooling and dehumidification

Growing demand for air conditioning in recent years has caused a significant increase in demand for primary energy resources. Solar-powered cooling is one of the environmentally-friendly techniques which may help alleviate the problem. A promising solar cooling method is through the use of a liquid desiccant system, where humidity is absorbed directly from the process air by direct contact with the desiccant. The desiccant is then regenerated, again in direct contact with an external air stream, by solar heat at relatively low temperatures. The liquid desiccant system has many potential advantages over other solar air conditioning systems and can provide a promising alternative to absorption or to solid desiccant systems.Earlier work by the authors included theoretical simulations and preliminary experiments on the key components of the liquid desiccant system. The objective of the present study has been to construct a prototype system based on the knowledge gained, to monitor its performance, identify problems and carry out preliminary design optimization. A 16 kWt system was installed at the Energy Engineering Center at the Technion, in the Mediterranean city of Haifa. The system comprises a dehumidifier and a regenerator with their associated components operating together to dehumidify the fresh (ambient) air supply to a group of offices on the top floor of the building. LiCl-water is employed as the working fluid. The system is coupled to a solar collector field and employs two methods of storage – hot water and desiccant solution in the regenerated state. The performance of the system was monitored for five summer months under varying operating conditions. The paper describes the operation of the experimental system and presents the measured data and the calculated performance parameters.     

开式除湿冷却型空调系统理想性能分析

利用热力学第二定律对热能驱动的任意结构型式的开式除湿冷却型空调系统进行了理论分析，得到了此类空调系统在可逆条件下的理想性能，并以一种改进型的开式除湿冷却型空调系统为例，模型分析了等效冷凝器的出口气流状况，等效蒸发器的出口气流状况等条件对系统理想性能系数的影响，为改进开式除湿冷却型空调系统的性能提供了有益的思路。     

Technical development of rotary desiccant dehumidification and air conditioning: A review

Rotary desiccant air conditioning system, which combines the technologies of desiccant dehumidification and evaporative cooling, is advantageous in being free from CFCs, using low grade thermal energy and controlling humidity and temperature separately. Compared with conventional vapor compression air conditioning system, it preserves the merits of environment-friendly, energy saving, healthy, comfortable, etc. Ongoing research and development works suggest that new desiccant materials and novel system configurations have significant potential for improving the performance and reliability and reducing the cost and size of rotary desiccant dehumidification and air conditioning system, thereby increasing its market competitiveness and breaking out the current fairly small niche market. For the purpose of providing an overview of recent efforts on these issues and showing how rotary desiccant air conditioning systems can be designed and coupled to available thermal energy, this paper presents and analyzes the status of rotary desiccant dehumidification and air conditioning in the following three aspects: the development of advanced desiccant materials, the optimization of system configuration and the utilization of solar energy and other low grade heat sources, such as solar energy, district heating, waste heat and bioenergy. Some key problems to further push forward the research and development of this technology are also summarized.     

Thermal storage in an air conditioning system with dual energy storage unit

在自行搭建的双蓄能实验平台上进行了制冷兼蓄热实验研究,对比了制冷兼蓄热模式和一般制冷模式,探讨了不同冷冻水流量和不同风机盘管风量对机组性能的影响.实验结果表明:蓄热对机组制冷端的影响很小,但是由于回收了大量的冷凝热,使得机组的综合能效比得到大幅提高,因此蓄热对空调节能具有较大作用.此外,在制冷兼蓄热模式下,冷冻水流量或风机盘管风量越大,机组的综合能效比越大,当风量为1033 m³/h,冷冻水流量为972 L/h时,机组综合能效比高达7.06.     

Case study and theoretical analysis of a solar driven two-stage rotary desiccant cooling system assisted by vapor compression air-conditioning

In this paper, a solar hybrid desiccant air conditioning system, which combines the technologies of two-stage desiccant cooling (TSDC) and air-source vapor compression air-conditioning (VAC) together, has been configured, experimentally investigated and theoretically analyzed. The system mainly includes a TSDC unit with design cooling capacity for 10 kW, an air-source VAC unit with 20 kW in nominal cooling capacity, a flat plate solar collector array for 90 m², a hot water storage tank and a cooling tower. Performance model of the system has been created in TRNSYS simulation studio. The objective of this paper is to report the test result of the solar hybrid air conditioning system and evaluate the energy saving potential, thereby providing useful data for practical application. Experimental results show that, under typical weather condition, the solar driven desiccant cooling unit can achieve an average cooling capacity of 10.9 kW, which contributes 35.7% of the cooling capacity provided by the hybrid system. Corresponding average thermal COP is over 1.0, electric COP is up to 11.48. Under Beijing (temperate), Shanghai (humid) and Hong Kong (extreme humid) weather conditions, the solar TSDC unit can remove about 57%, 69% and 55% of the seasonal moisture load, thereby reducing electric power consumption by about 31%, 34% and 22%, respectively. These suggest that the solar hybrid system is feasible for a wide range of operating conditions.     

Performance enhancement of a subcooled cold storage air conditioning system

This article experimentally investigates the enhancement of thermal performance for an air conditioning system utilizing a cold storage unit as a subcooler. The cold storage unit is composed of an energy storage tank, liquid-side heat exchanger, suction-side heat exchanger and energy storage material (ESM), water. When the cooling load is lower than the nominal cooling capacity of the system, the cold storage unit can store extra cold energy of the system to subcool the condenser outlet refrigerant. Hence, both the cooling capacity and coefficient of performance (COP) of the system will be increased. This experiment tests the two operation modes: subcooled mode with energy storage and non-subcooled mode without energy storage. The results show that for fixed cooling loads at 3.05 kW, 3.5 kW and 3.95 kW, the COP of the subcooled mode are 16.0%, 15.6% and 14.1% higher than those of the non-subcooled mode, respectively. In the varied cooling load experiments, the COP of the subcooled cold storage air conditioning system is 15.3% higher than the conventional system.     

A feasibility study of a solar desiccant air‐conditioning system—Part I: psychrometrics and analysis of the conditioned zone

A desiccant dehumidifier in conjunction with evaporative coolers can reduce air conditioning operating costs significantly since the energy required to power a desiccant cooling system is small and the source of this required energy (solar, waste heat, natural gas) can be diverse. Such a solid desiccant cooling system with a backup vapour compression system is simulated and the performance of the system is evaluated to study its feasibility in four cities in the United States. This paper describes the relevant psychrometric calculations and analyses of the conditioned zone required for simulating the transient performance of the system. Copyright © 1999 John Wiley & Sons, Ltd.