Solar air conditioning and its role in alleviating the energy crisis of the Mediterranean hotels

The Intergovernmental Panel on Climate Change has estimated that the Mediterranean region could experience an increase in annual mean temperatures up to 7.1°C by the end of the century. Within the same time frame, the fossil fuel stocks are predicted to diminish, resulting in ever increasing fuel prices. Furthermore, there is continuous political pressure to impose greenhouse gas levies and quotas for industries and services alike, thus adding into their operational expenditures should they exceed their carbon quotas. The hotel industry, in particular, is predicted to suffer from the direct and indirect effects of climate change and increasing fuel prices. Not only are their operating costs bound to increase but in addition, they may suffer from reduced tourist flows if and when the airline industry is forced to increase travel prices. It is in this context of a predicted ‘energy crisis’ within the hotel industry that this study was undertaken in order to evaluate the extent to which hotels can future-proof their operations.

Integration of renewable energy sources into hotel operations is perceived as the most promising form of crisis mitigation. In the Mediterranean region, the availability of solar irradiation is abundant and free from microclimatic limitations associated with wind energy in comparison. Therefore, solar-assisted air conditioning was identified as a key strategy because its operational principal dictates that the greatest availability of energy coincides with the peak demands.

The aim of this article is to review the currently available solar air-conditioning technologies, their energy saving potential and technical limitations. The study is based on a literature review supplemented with information available from equipment vendors. Subsequently, the objective of this article is to set solar air-conditioning equipment selection criteria that could assist hotels of various service classes in their energy planning and equipment upgrades.     

过渡季节隔板式工位空调房间气流组织的数值模拟

现代办公楼由于室内发热设备增多,部分房间在过渡季节也需要制冷,传统空调按夏季工况设计选用的设备容量较大,不能适应过渡季节小负荷运行的需要。工位空调是一种人性化的空调形式,直接将新鲜空气送到人的呼吸区,在过渡季节通过工位空调,充分利用室外新风消除室内负荷是一种可行的空调方式。利用CFD仿真软件对一间使用隔板式工位空调办公室的过渡季节的温度场、速度场进行仿真,得出了空气温度、流速的分布图,并对模拟房间进行了实验测试,对模拟结果与实测结果进行了分析比较。分析结果表明模拟值与实测值的吻合度较好,认为该空调房间的气流组织是符合要求的。最后指出,仿真应该和实验有机的结合起来,才能更有效的解决专业问题。     

酒店空调冷凝热回收技术的应用研究

通过深入分析空调负荷与热水负荷的耦合关系,提出了一种充分利用制冷机组回收的废热提供生活热水的设计方法,并把这种突破性做法与传统的空调和热水供应系统进行比较,探讨利用酒店的空调冷凝热回收技术制备生活热水,以寻求一个技术可行、低能耗和无污染的空调和热水供应系统方案.     

大温差空调系统在酒店工程中的应用

从节能考虑,在佛山某酒店项目的设计中应用了大温差空调冷水系统,介绍了本工程的!￡调系统,并给出了空调系统图,同时介绍了空调末端设备的产冷量是如何修正的。     

发展燃气空调的优越性及可行性

主要从环境保护、能源利用、气网削峰填谷,削减电力峰值等方面介绍了燃气空调的优越性及其特点。并从当前国内燃气开发利用情况、政府政策及国产燃气空调主要设备技术性能方面阐述了发展和应用燃气空调的可行性。     

Residential energy savings through modified control of space-conditioning equipment

Energy requirements for heating and cooling homes depend strongly on how the space conditioning equipment is operated. Using detailed computer simulations for a typical house, the energy savings for decreasing winter thermostat settings and for further reductions during the night are given as a function of climate. Similarly, the energy savings for increased thermostat settings during the air-conditioning season are given for the coterminous states. Air-conditioning requirements can also be reduced by allowing natural ventilation to cool homes under certain outdoor conditions. A comparison between air-conditioning only and a combination of air-conditioning and opening windows is given for the coterminous states. Energy savings for all of these options are highly dependent upon local climates. Total savings from adoption of these behavioral changes are equivalent to one-fourth of U.S. imported petroleum.     

Research on performance of mixed absorption refrigeration for solar air-conditioning

A novel lithium bromide/water mixed absorption refrigeration cycle that is suitable for the utilization of solar air-conditioning and can overcome the drawbacks of low system overall efficiency of traditional solar absorption refrigeration air-condition systems is presented. The accessorial high pressure generator was added in the cycle. The lithium bromide solution flowing out from the high pressure generator was mixed with the solution from the low pressure absorber to increase lithium bromide solution concentration and decrease pressure in the high pressure absorber. The performance of a mixed absorption refrigeration cycle was analyzed. The theoretical analysis shows that the highest COP is 0.61, while the highest available temperature difference of heat resource is 33.2°C. The whole coefficient of performance of the solar air-conditioning using mixed absorption cycle is 94.5% higher than that of two-stage absorption. The advantages of solar air-conditioning can be markedly made use of by the cycle.     

Underground water-source loop heat-pump air-conditioning system applied in a residential building in Beijing

In this paper, we report on an underground water-source water-loop heat-pump (UWSWLHP) air-conditioning system for a tall apartment building in Beijing. Water at 14 °C was used as an external low-temperature heat-source. By analyzing field-test data for two years, the authors assessed the operating and controlling conditions of the system. Based on the electricity consumed by public-use air-conditioning power equipment and terminal heat-pumps, the authors put forward an overall evaluation of the energy-conservation characteristics of the system.     

溴化锂吸收式机组在空调设计当中的应用

叙述了空调设计中溴化锂吸收式机组及其配套设备选型及应用的情况,结合实际工程深入讲解了整个设计原理及流程,以供在设计、施工时参考。     

太阳能液体除湿空调性能的实验研究

在对液体除湿机理研究的基础上，建立了太阳能液体除湿空调系统实验台，采用氯化钙溶液作为除湿剂，对系统的除湿性能进行了实验研究，对影响除湿的各主要因素进行了分析。     

建筑节能技术探讨

由于建筑物的设计中有不合理之处,导致建筑物的空调负荷偏大,使建筑物增加了一部分不必要的能耗。建筑物里的空调系统设计方案也存在很多缺陷,使能耗过大。本文从建筑物和空调系统两方面进行分析,分别对建筑物及空调系统的节能技术措施进行了探讨。其主要节能技术措施有:使建筑物的规划设计科学、增强围护结构的隔热保温性能、使空调系统设计更科学合理、提高空调系统的管理意识。     

Perspectives of solar cooling in view of the developments in the air-conditioning sector

Changes in the standards of thermal comfort in the urban microclimate and in the capital cost of air-conditioning equipment have drastically increased the energy consumption in the building sector over the last decade. At the same time, the integration of renewable energy systems, mainly active solar ones, in buildings has been an area of intense research over the last 30 years. This has also been the case in the field of solar refrigeration, mainly in the field of sorption systems. The analysis discussed in the paper is focused on the state of the art of thermal solar systems use and on the possibilities of combining those with state of the art technologies in sorption refrigeration, in order to cover the cooling demand of residential and commercial buildings. This was done by assessing the available solar and refrigeration technologies as well as by highlighting the situation in the building market, as this is still the dominant factor for the propagation of such systems.     

Research on performance of mixed absorption refrigeration for solar air-conditioning

A novel lithium bromide/water mixed absorption refrigeration cycle that is suitable for the utilization of solar air-conditioning and can overcome the draw-backs of low system overall efficiency of traditional solar absorption refrigeration air-condition systems is presented. The accessorial high pressure generator was added in the cycle. The lithium bromide solution flowing out from the high pressure generator was mixed with the solution from the low pressure absorber to increase lithium bromide solution concentration and decrease pressure in the high pressure absorber. The performance of a mixed absorption refrigeration cycle was analyzed. The theoretical analysis shows that the highest COP is 0.61, while the highest available temperature difference of heat resource is 33.2°C. The whole coefficient of performance of the solar air-conditioning using mixed absorption cycle is 94.5% higher than that of two-stage absorption. The advantages of solar air-conditioning can be markedly made use of by the cycle. __________ Translated from Journal of Huazhong University of Science and Technology, 2006, 34(8): 62–64 [译自: 华中科技大学学报]     

大型建筑中应用应急柴油发机实现冷热电三联供及其实例分析

介绍了一种新型的高效节能中央空调冷暖系统－自备发电、余热利用及热泵冷暖系统。该系统充分发挥了大型建筑必备设备－自备电源应急柴油发电机的作用,使一次能源在使用中更加符合热力学的原理;该系统不追求某一种机组的高COP,而是利用各种设备的优点,有机匹配,以求一年中最高效的节能。通过与三种常规冷暖系统的一次能源利用率比较,得出该新型冷暖系统的一次能源利用率比三种常规冷暖系统的一次能源利用率高27．88％－104．6％以上。并通过实例计算了采用该系统的某大型广场的全年经济效益。     

Development of adsorption air-conditioning technology using modified activated carbon – A review

Adsorption air-conditioning technology has attracted much attention recently due to its environmental friendly property. Some successes have been reported in the literature on the adsorption technology for air-conditioning applications. This paper presents an overview of the researches which had been carried out on adsorption refrigeration system with the commonly used adsorbent and adsorbate working pairs, solar adsorption refrigeration and adsorption technologies in automobile. Activated carbon has been widely used as the adsorbent in adsorption refrigeration system. However, one of the bottlenecks which prevent the improvement of the adsorption refrigeration technology using activated carbon is the use of the readily available commercial activated carbon without prior treatment, which has resulted in relatively lower performance as compared to the conventional absorption and vapour compression technologies. Various modification methods on activated carbon are thus discussed in this paper for future development and improvement of adsorption air-conditioning system.     

Energy and economic performance analysis of an open cycle solar desiccant dehumidification air-conditioning system for application in Hong Kong

In this article, a transient simulation model and the EnergyPlus were used to study the energy performance and economical feasibility for integrating a solar liquid desiccant dehumidification system with a conventional vapor compression air-conditioning system for the weather condition of Hong Kong. The vapor compression system capacity in the solar assisted air-conditioning system can be reduced to 19 kW from original 28 kW of a conventional air-conditioning system as a case study due to the solar desiccant cooling. The economical performance of the solar desiccant dehumidification system is compared with that of the conventional air-conditioning system. The results show that the energy saving potentials due to incorporation of the solar desiccant dehumidification system in a traditional air-conditioning system is significant for the hot wet weather in Hong Kong due to higher COP resulted from higher supply chilled water temperature from chiller plants. The annual operation energy savings for the hybrid system is 6760 kWh and the payback period of the hybrid system is around 7 years. The study shows that the solar assisted air-conditioning is a viable technology for utilizations in subtropical areas.     

户式中央空调的能耗分析

传统的家用分体式空调由于其能耗高、舒适性差等缺点现已逐渐被具有能耗低、舒适性好、运行管理方便等优点的户式中央空调所取代,户式中央空调也将成为家用空调的主导方向。本文选取了建筑面积为130m2的典型户型,从工程应用方面对比分析了传统的分体式空调与家用中央空调的能耗。结果表明:户式中央空调比传统的分体式空调节能近40%,以上海地区为代表的东部地区为例,全年运行能节电3000多kWh,具有显著的节能效果。     

土壤源--水环式热泵空调系统的设计

本文简要阐述了土壤源———水环式热泵空调系统的工作原理,以及该系统不同于常规水环热泵空调系统的特点,接着介绍了某应用土壤源———水环式热泵空调系统所具有的设计特点。     

An energy-efficient air-conditioning system for hydrogen driven cars

In this paper a new operation principle of an air-conditioning system for hydrogen driven cars is proposed and experimental results of a laboratory prototype are presented. The system is able to utilize the potential energy of the compressed hydrogen gas as main driving energy to generate a cooling effect usable for e.g. air-conditioning. Therefore, it is able to partially reuse the compression energy originally spent in order to increase the energy density of hydrogen but is so far wasted onboard. The underlying principle of the process is based on a chemical reaction of a metal hydride (Ti_0.99Zr_0.01V_0.43Fe_0.09Cr_0.05Mn_1.5) with hydrogen at different pressures and corresponding equilibrium temperatures. The laboratory prototype consists of two alternating capillary tube bundle reactors (together around 5 kg and 1.5 l) and is able to generate a quasi-continuous cooling effect at 13 °C in the order of 900 W.     

展望燃气空调

随着我国实施西气东输工程 ,将西部丰富的天然气资源送到东部经济发达地区 ,为发展燃气空调提供了一个非常好的契机。发展燃气空调不仅有利于大气环境保护、减少温室气体排放量 ,而且还可有效减少由于电力空调引起电力供应的峰谷差 ,提高电厂的发电效率。介绍了燃气空调的特点及其在国内外的发展情况及市场展望