蒸发冷却与溶液除湿复合空调系统的应用

根据长江流域高温高湿的气候条件,构建了两级蒸发冷却与溶液除湿相结合的复合空调系统。介绍了复合空调系统的流程,根据该地区的气候条件和相关的空调设计参数,比较了复合空调系统与一次回风空调系统的能耗。在设计工况下,复合空调系统的能效比为2.6,相比于一次回风空调系统的节能率为47.2%。     

Energy saving through evaporatively cooled condenser air in conventional air-conditioning units

A theoretical study of the feasibility of evaporative cooling of the condenser air of a conventional vapour compression air-conditioning system to upgrade the rating of an air-cooled air-conditioning unit and consequent energy saving in the Delhi climate is presented. A brief review of the heat rejection option in an air-conditioning unit has been given and a theoretical background analysis for evaporative cooling of condenser air has also been presented. For illustration, one specific air-cooled package unit, whose performance characteristics as given by the manufacturers are available, has been used for calculations. Temperature variation data for New Delhi in the months of May and June 1991, obtained from the Meteorological Department, has been used. With the basic data, the upgradation of cooling capacity, power requirement and average energy consumption with and without evaporative cooling of condenser air has been calculated and the reduction in peak load and saving in the average energy consumption was predicted. Typical calculations of the water requirements for pre-cooling of condenser air were also predicted and compared with the corresponding requirements for water-cooled and evaporative condensers. It is concluded that there is an excellent and exciting possibility of reducing energy consumption (and consequent enhanced energy saving) in air-conditioning at national level.     

Energy savings in a building using regenerative evaporative cooling

This paper explores the potential of reducing the annual energy consumption of a central air-conditioned building through advanced evaporative cooling systems. The building considered is a typical three floor library building of a University. The regenerative evaporative cooling technology is coupled with the liquid cooled water chiller system to accomplish the energy conservation objective. Comparisons of the regenerative evaporative cooling are made with simple evaporative cooling to bring out the importance such a system. The well-known building simulation software, TRNSYS is used to carry out the heat load calculations and the dynamic simulations of the building. Annual energy consumptions of different components of the air-conditioning system are estimated for the existing water chiller system as well as for both coupled evaporative cooling systems (simple and regenerative). The annual energy consumptions, the indoor temperature, the relative humidity and the thermal comfort index ‘PMV’ are compared for all the three different air-conditioning systems. The coupling of direct and regenerative evaporative cooling technologies with water chiller system has shown, respectively, 12.09% and 15.69% savings in annual energy consumption of the building, while maintaining PMV between ?1 and +1 for most of the hours in the year.     

热管间接蒸发和吸湿冷却空调系统应用分析

间接蒸发和吸湿冷却在空调系统中得到广泛应用。热毛细泵循环式热管是一种能远距离传输能量且热阻低、传递温降小的高效热交换器。本文介绍了该新型热管用于间接蒸发和吸湿冷却空调系统热回收的工作原理，对该新型热管的原理及运行的毛细极限进行分析。对热管间接蒸发和吸湿冷却空调系统的性能进行模拟和分析。结果表明，热管间接蒸发与吸湿冷却空调系统是一种节能复合空调器系统。     

A combined system of chilled ceiling,displacement ventilation and desiccant dehumidification

Different types of heating, ventilation, and air-conditioning (HVAC) systems consume different amounts of energy yet they deliver similar levels of acceptable indoor air quality (IAQ) and thermal comfort. It is desirable to provide buildings with an optimal HVAC system to create the best IAQ and thermal comfort with minimum energy consumption. In this paper, a combined system of chilled ceiling, displacement ventilation and desiccant dehumidification is designed and applied for space conditioning in a hot and humid climate. IAQ, thermal comfort, and energy saving potential of the combined system are estimated using a mathematical model of the system described in this paper. To confirm the feasibility of the combined system in a hot and humid climate, like China, and to evaluate the system performance, the mathematical model simulates an office building in Beijing and estimates IAQ, thermal comfort and energy consumption. We conclude that in comparison with a conventional all-air system the combined system saves 8.2% of total primary energy consumption in addition to achieving better IAQ and thermal comfort. Chilled ceiling, displacement ventilation and desiccant dehumidification respond consistently to cooling source demand and complement each other on indoor comfort and air quality. It is feasible to combine the three technologies for space conditioning of office building in a hot and humid climate.     

Ceiling mounted personalized ventilation system in hot and humid climate—An energy analysis

This study is to evaluate energy saving potential of ceiling mounted personalized ventilation (PV) system in conjunction with background mixing ventilation compared with mixing ventilation system alone and with mixing ventilation system when occupants are provided with individually controlled desk fans for generating additional air movement at each desk. Control strategy applied includes different number of personalized ventilation air terminal devices used and different PV airflow rates supplied. Energy calculation is based on design conditions in Singapore, representing a hot and humid climate. The results reveal that increasing room temperature can save cooling energy when the combination of PV with ceiling mounted personalized ventilation nozzles and background mixing ventilation is used. In this case the energy for transport of air increases but the total energy decreases, i.e. energy can be saved due to elevated room temperature. Comparing with mixing ventilation plus desk fans, ceiling mounted personalized ventilation cannot only realize better cooling effect but also decrease the total energy consumption.     

Advancement of solar desiccant cooling system for building use in subtropical Hong Kong

The solar desiccant cooling system (SDCS) had a saving potential of the year-round primary energy consumption as compared to the conventional air-conditioning system for full fresh air application in the subtropical Hong Kong. In order to further enhance its energy efficiency, advancement of the basic SDCS was carried out through a strategy of hybrid design. Six hybrid system alternatives of SDCS were therefore proposed, three for full fresh air design while another three for return air design for the building zone. Year-round performance evaluation of each solar hybrid desiccant cooling system was conducted for typical office application under different climatic and loading conditions. All the six hybrid system alternatives were found technically feasible, with up to 35.2% saving of year-round primary energy consumption against the conventional air-conditioning systems. Among the hybrid alternatives, recommendations were made on the SDCS hybridized with vapour compression refrigeration for full fresh air design; and the SDCS hybridized with vapour absorption refrigeration for return air design, since they had the saving potentials of both primary energy and initial cost. These two hybrid system alternatives used evacuated tubes, a more economical type of solar collectors compared to the PV or PVT panels.     

Indirect evaporative cooling potential in air–water systems in temperate climates

Recent developments have prompted a review of evaporative cooling technology as an effective means of cooling modern deep plan buildings. Prominent among these developments is the success of high temperature sensible cooling systems, particularly, chilled ceilings, which require a supply of cooling water at 14–18 °C. Crucial to the success of evaporative cooling technology, as a significant means of cooling in modern applications, is the ability to generate cooling water, in an indirect circuit, at a temperature which closely approaches the ambient adiabatic saturation temperature (AST) or wet bulb temperature (WBT). Recent experimental research has demonstrated that it is technically viable to generate such cooling water at a temperature of 3 K above the ambient AST.While the frequency of ambient AST occurrence can be obtained from meteorological sources, there is little in-depth analysis of the potential for this form of cooling water generation, based on the approach temperatures which have now been shown to be viable. The decision to use an evaporative cooling system depends largely on an assessment, in-depth, of net energy saved against capital expended. Such an assessment requires detailed data on the availability of cooling water, generated by evaporation, for each location. This paper quantifies evaporative cooling availability in-depth for a northern and southern European city, Dublin and Milan and suggests a method of analysing such data for any world wide location, for which suitable meteorological records are available. The paper, incorporates recent experimental research findings and bases the availability analysis on meteorological test reference weather year data.The results of this research confirm a major potential for the generation of cooling water by evaporative means, which can be used to provide effective cooling of deep plan buildings by means of contemporary water based sensible cooling systems, such as fan coil systems, radiant chilled ceiling panels and ceiling cooling convectors (chilled beams). While the technique offers most potential in locations with a northern European temperate climate, it has significant potential to contribute to cooling in some southern European cities, during the non-summer months and also at other times, particularly where load shaving techniques are incorporated.     

西北干旱地区的空调系统节能设计

针对西北地区独特的气候特点,分别提出了蒸发冷却+置换通风和蒸发冷却+干式风机盘管2种空调系统形式可在喀什地区实际工程中应用。通过对比发现,第1种系统形式比传统电制冷空调系统节能53%,第2种系统形式比传统电制冷系统的制冷机房内设备节能71%,2种系统节能效果显著。通过对送风状态点露点分析,蒸发冷空调系统无凝结水产生,可避免室内环境污染。蒸发冷却空调系统的独特优势决定了其在西北地区的广泛应用前景。     

Modelling and performance prediction of an integrated central cooling plant for HVAC energy efficiency improvement

The aim of this paper is to explore methods to reduce the energy consumption of a central cooling plant. To achieve this, we have developed a new design for heating, ventilating and air conditioning (HVAC) efficiency improvement. A storage tank together with an immersed heat exchanger is installed in the discharge line between the compressor and condenser. The heat exchanger uses the make-up water of the cooling tower to reduce the refrigerant temperature entering the condenser. To investigate the potential of energy savings, we used a real-world commercial building with a central cooling plant, located in a hot and dry climate, for our case study. The energy consumption and relevant data of the existing central cooling plant were acquired over the course of a typical week in summer. The integrated system has been modeled and analyzed to achieve energy conservation. The performance of the proposed cooling system was simulated using a transient simulation software package. Comparison of the proposed system with existing cooling plant is included in this paper to demonstrate the advantages of our new configuration. Results show that up to 18% power saving can be obtained by using our design.     

蒸发冷却空调新风系统的全年应用研究

结合干热、严寒或寒冷地区全年气候特点及冬夏季建筑能耗特性,通过逐时新风能耗模拟计算,得到设置热回收装置的全年用蒸发冷却空调系统冬季新风节能量远大于夏季节能量,选用热回收装置时应重点关注冬季热回收效率,各类热回收装置中转轮热回收装置全年节能量最大,节能效果最好。基于此,深入分析了蒸发冷却空调系统冬夏季新风加湿需求、新风量变化范围和水系统管径选择,给出了全年用蒸发冷却空调机组冬季运行的防冻措施。     

冷却吊顶供水方式对系统运行能耗的影响

通过对冷却吊项运行能耗的计算机动态模拟，分析了供水方式、新风系统形式、冷却塔供冷、制冷机冷水温差等因素对系统能耗的影响，认为采用冷却吊项水系统与新风系统独立的水系统形式，并结合冷却塔自然供冷，节能效果最好。建议生产厂家开发小温差、大流量、低流动阻力的冷水机组，以推动冷却吊项的应用。     

蒸发冷却技术在非干燥地区的应用

本文提出蒸发冷却技术在非干燥地区有广阔的应用前景，它在改善炎热环境、除湿法供冷和扩大传热温差以改善设备性能等方面都能起明显的作用。文章介绍了应用方法并分析了节能效果。     

香港地区溶液除湿与蒸发冷却复合系统的节能分析

本文提出了溶液除湿与蒸发冷却相结合的复合系统,并根据香港地区的气候条件和相关的空调设计参数,将该复合系统的能耗与一次回风空调系统的能耗进行对比.计算结果表明,在设计工况下复合系统的节能率为21.3%.当采用太阳能、地热等可再生能源或其它废热时,系统的节能率更大.结果表明该复合系统在香港具有较好的运用前景.     

The effect of heat-pipe air-handling coil on energy consumption in central air-conditioning system

A study was carried out to investigate the effect of heat-pipe air-handling coil on energy consumption in a central air-conditioning system with return air. Taking an office building as an example, the study shows that compared with conventional central air-conditioning system with return air, the heat-pipe air-conditioning system can save cooling and reheating energy. In the usual range of 22–26 °C indoor design temperature and 50% relative humidity, the RES (rate of energy saving) in this office building investigated is 23.5–25.7% for cooling load and 38.1–40.9% for total energy consumption. The RES of the heat-pipe air-conditioning system increases with the increase of indoor design temperature and the decrease of indoor relative humidity. The influence of indoor relative humidity on RES is much greater than the influence of the indoor design temperature. The study indicates that a central air-conditioning system can significantly reduce its energy consumption and improve both the indoor thermal comfort and air quality when a heat-pipe air-handling coil is employed in the air-conditioning process.     

围护结构空调器与建筑节能减排技术分析

讨论了围护结构形式的空调节能减排技术。通过分析围护结构特性及被动式空调系统的技术措施,以及在驱动能源、系统构成与运行、功能形成、节能减排等方面与主动式系统的比较,提出利用太阳热、地热等可再生能源被动式调控建筑环境,建筑物围护结构实质为围护结构空调器,论述了其定义、分类、节能减排、技术措施、开发方向等。从冷热量的产生、储存、传热各环节及自控调节等方面分析围护结构空调器的负荷、功能等及节能效果,建议加强开发应用以实现建筑节能减排,讨论了该技术的开发应用关键与发展方向。     

天棚辐射供冷系统换热过程的研究

天棚辐射供冷是一种舒适度很高的新型空凋技术。系统的供冷能力和天棚表面温度是系统设计和运行的关键，研究它们与影响因素之间的关系是十分重要的：通过建立天棚辐射供冷系统的物理模型和数学模型，对控制方程进行数值模拟，给出了影响系统供冷能力的诸多因素之间的关系。研究结果显示：冷水温度越低，天棚表面温度越低，系统提供的冷量越大。天棚表面与室内环境之间的辐射换热量大于对流换热量，舒适度好。管子埋深越大，天棚表面温度越大，换热能力越小，但差别不显著：埋管间距越大，天棚表面温度越大，换热能力越小，所以埋管间距不宜取得过大。埋管管径的变化对天棚表面温度及换热量的影响不大。研究结果可为实际工程的设计、运行参数的选择和系统的可行性分析提供依据和指导。     

天棚辐射混凝土板显热蓄能特性研究

普通天棚混凝土板利用混凝土板的显热特性蓄能.与常用的墙体蓄能(潜热蓄能)不同,混凝土板显热蓄能能力小,但由于其不增加初投资、对现有建筑无需改造等优点,其减少空调系统运行费用的潜力不可忽视.通过Fluent模拟和数据分析,给出天棚辐射混凝土板的蓄能能力随特征温差及管间距变化的曲线.对于某一节能建筑,利用天棚辐射混凝土板的...     

无保温楼板辐射供冷系统热过程的研究

楼板辐射供冷是一种舒适度很高的新型空调技术：楼板内若不设保温层，天棚和地板均成为冷辐射表面向房间供冷：系统的供冷能力和楼板上下表面温度是空调供冷系统运行和调节的关键参数，研究它们与影响因素之间的关系是十分重要的。本文建立了无保温楼板辐射供冷系统的物理模型和数学模型，并对控制方程进行数值模拟，给出了系统供冷能力和楼板上下表面温度和诸多影响因素之间的关系。研究结果显示：冷水温度越低，天棚和地板的表面温度越低，系统提高的冷量越大；天棚表面温度略大于地板表面温度；随着冷水温度的升高，天棚和地板之间的温度差异将减小，房间的舒适性好；地板辐射换热量远大于对流换热量，天棚辐射换热量略大于对流换热量；天棚提供给房间的冷量大于地板提供的冷量。且冷水温度越低，相差越大；管子埋深越大，天棚和地板表面温度越大，系统供冷量越小，但差别不显著；埋管间距越大，天棚和地板表面温度越大，系统供冷量越小；埋管管径越大，天棚和地板温度越小，系统供冷量越大，但差异不显著。研究结果可为实际工程的设计、运行参数的选择和系统的可行性分析提供依据和指导。     

热管在多联机卧式暗装室内机中节能应用探讨

以某品牌多联机三个型号卧式暗装室内机为例,将热管技术应用于多联机卧式暗装室内机,计算不同室内设计温度条件换热量,研究结果表明,与传统多联机室内机相比较,其冷量节能率可达20．94％～33．73％,同时在无需电加热或蒸汽动力设备的条件下提高室内送风温度,达到节约能源消耗的同时满足室内人体热舒适的要求。