新风除湿辅助毛细管辐射供冷房间流场模拟

建立毛细管辐射供冷系统传热模型。对分别采用单纯毛细管辐射供冷系统、新风除湿辅助毛细管辐射供冷系统的空调房间内的温度场、速度场进行模拟。采用新风除湿辅助毛细管辐射供冷系统,室内可达到更为舒适的温度范围,在工作区内无吹风感。     

使用天然气的除湿供冷系统

文章阐述了除湿供冷系统的结构和原理，并分析了影响除湿性能的一些因素。在与传统的制冷技术作比较的同时，评价了该系统的优越性。该系统不仅节约能源，还有助于提高室内空气品质和环保。     

夏季湿热地区置换通风和冷却顶板复合系统节能潜力研究

根据上海一办公楼置换通风和冷却顶板复合系统的设计及运行特点,应用EnergyPlus软件模拟了采用转轮除湿方式的复合系统的供冷季能耗,并分别模拟了采用冷却除湿方式的复合系统、带热回收装置的混合通风系统和置换通风系统的供冷季能耗以进行对比。结果表明,在湿热地区采用转轮除湿方式可比冷却除湿方式节约制冷机冷量,空调季总能源费用比混合通风系统节约30%左右。     

某辐射空调工程设计与应用研究

本文以南京某会所空调系统为例,介绍了顶棚辐射板供冷(暖)和转轮除湿新风机组相结合的空调系统设计方案,顶棚辐射板供冷(暖)系统的特点及安装方式、转轮除湿新风机组、空调冷热源系统及温湿度独立控制系统的设计要点。     

辐射供冷空调系统防结露研究综述

本文综述了目前辐射供冷末端防结露技术的研究进展,主要从末端供水控制,独立送风除湿,优化辐射板参数及自控方式四方面进行综述,并对当前研究中存在的不足进行总结,为辐射供冷空调系统防结露的进一步研究方向提供参考.     

辐射供冷加新风系统适用场所与运行控制策略

在设定条件下,对辐射供冷+新风系统中辐射板表面结露的现象进行了分析。提出以单位质量新风除湿能力作为指标初步判断各种公共建筑是否适用辐射供冷+新风系统。对辐射供冷+新风系统的温湿度独立控制运行原理进行了革新,提出优先控制湿度的运行策略。     

国外暖通空调实用文献摘要选编

高效屋顶式空调机组在小型商用空调中使用可能的节能效果，盘管环路式热回收装置的解析，自然通风——新的计算方法，除湿法空调，夜间通风被动供冷的设计 应用实测数据对参数模型和建筑模拟进行的评估，博物馆的环境参数，没有风管的VAV系统，除湿法空调，关于预测高大厂房局部空调供冷供暖负荷的实验研究，特殊环境空调4 精密温度控制室。     

辐射供冷空调末端防结露研究进展

辐射供冷空调的末端易结露是限制其供冷能力和实际工程应用的重要科学问题。本文综述了目前辐射供冷末端防结露技术的研究进展,主要从末端供冷表面处理、调控末端供水温度、独立送风除湿措施、新材料技术等四方面进行综述。对当前防结露研究存在的不足进行探讨,提出利用新材料技术可以解决结露问题和提升供冷能力,对辐射供冷空调末端防结露的研究方向进行了展望。     

辐射供冷空调防结露机理及相关技术分析

辐射冷板夏季供冷时的结露问题是目前阻碍这一系统广泛应用的最大障碍,结露是必须重视并应杜绝的现象。本文分析了辐射供冷空调防结露控制机理,探讨了防结露对独立新风系统的要求。总结分析了国内外相关防结露技术,并提出了适宜我国国情的防结露技术。采用提高进水温度、匹配新风除湿系统等合理的基础设计措施是辐射供冷空调防结露工作得以顺利进行的前提,加强系统运行阶段的防结露控制是保障室内环境安全性的有力措施。对于国内常用的混凝土预埋管辐射冷板,由于其冷延迟特性,通过控制新风系统控制室内空气露点温度做为防结露的主要措施更为合理。     

不同除湿方式户式辐射空调系统能耗研究

模拟比较了冷水式除湿、制冷剂直膨式除湿、双冷源除湿3种除湿方式下户式辐射空调系统的夏季供冷能耗。结果显示:3种除湿方式下,空调房间温度均能满足要求,采用制冷剂直膨式除湿时室内温度略低,双冷源除湿时室内温度略高;采用制冷剂直膨式除湿的户式辐射空调系统能耗最低,冷水式除湿能耗最高,直膨式除湿的能耗较冷水式除湿约低15%,较双冷源除湿约低10%。     

Overall cooling efficiency of a solar desiccant plant powered by direct-flow vacuum-tube collectors: simulation and experimental results

Using solar thermal energy is an interesting option for heat-driven air conditioning, e.g. desiccant cooling. In this article, the autonomous operations of a solar desiccant cooling plant powered by direct-flow vacuum-tube collectors are investigated. A model of the solar installation and the desiccant air handling unit is presented and implemented in the SPARK simulation environment and then it is validated experimentally. The overall cooling efficiency of the system is evaluated using simulation for humid and moderately humid climates and the effect of increasing the regeneration temperature on the cooling capacity, the overall cooling efficiency is studied and finally the overall efficiency of the collectors is calculated for the studied cases.     

Exergetic modeling and experimental performance assessment of a novel desiccant cooling system

New approaches to space conditioning of buildings are required to resolve economic, environmental, and regulatory issues. One of the alternative systems that is brought to agenda is the desiccant cooling systems, which may provide important advantages in solving air conditioning problems. This study deals with the performance analysis and evaluation of a novel desiccant cooling system using exergy analysis method. The system was designed, constructed and tested in Cukurova University, Adana, Turkey and has been successfully operated since 2008. This system consists of a desiccant wheel, heat exchangers, fans, evaporative cooler, electric heater unit and refrigeration unit. The exergy transports between the components and the destructions in each of the components of the desiccant cooling system are determined for the average measured parameters obtained from the experimental results. Exergy efficiencies of the system components are determined in an attempt to assess their individual performances and the potential for improvements is also presented. The exergetic efficiency values for the whole system on the exergetic product/fuel basis are calculated to range from round 32% to 10% at the varying dead (reference) state temperatures of 0-30 °C.     

TRNSYS simulation for solar-assisted liquid desiccant evaporative cooling

ABSTRACT

Recently, desiccant cooling systems are well thought of as a competent method for controlling the water content in the air. A solar flat-plate collector has been used as it decreases the dependency on non-renewable resources. Solar-aided liquid desiccant systems have been used to reduce the dependency of air-conditioning systems on non-renewable sources of energy. Manipal’s humid and searing climate provides certain benefits in setting up such a system. The suggested system has reliability and equipment life and also takes complete advantage of the available solar energy for the renewal of the liquid desiccant. TRNSYS simulation is used to predict the efficiency and feasibility of the system. The temperature and energy-load variations were successfully obtained. An effective simulation was developed whereby the solar air conditioning of a room was indicated.     

CO2跨临界循环和除湿法冷却联合循环系统的研究

为有效回收和利用CO2跨临界循环的气体冷却器排气热量，提出了一种将除湿法冷却供冷和CO2跨临界循环结合起来的系统方式，介绍了系统的组成和特点，分析了系统的循环效率、可行性和经济性，指出该方式可有效提高系统的综合能源利用效率，并可满足全年的空调要求。     

溶液除湿蒸发冷却空调系统及其若干重要问题

从系统流程的构建、系统性能的研究、系统关键部位的优化等方面介绍了溶液除湿蒸发冷却空调系统的研究情况,探讨了进一步研究中的关键问题.     

Study on a novel thermally driven air conditioning system with desiccant dehumidification and regenerative evaporative cooling

Existing desiccant cooling systems reduce the temperature of process air either by adopting evaporative coolers or incorporating vapor compression systems. While the former is restricted by inaccurate control, the latter still consumes certain quantity of electric power. To solve this problem, a thermally driven air conditioning system, which combines the technologies of rotary desiccant dehumidification and regenerative evaporative cooling, has been proposed and investigated. In addition to dehumidification, the system is capable of producing chilled water, thereby realizing separate temperature and humidity control without increasing electrical load. To find out the characteristics of produced chilled water and evaluate the feasibility and energy saving potential of this novel system, a mathematical model has been developed. Case studies have been conducted under Air conditioning and Refrigeration Institute (ARI) summer, ARI humid and Shanghai summer conditions. It is found that the system can achieve a thermal COP higher than 1.0 and an electric COP about 8.0. The temperature of chilled water produced by the system is around 14–20 °C. This chilled water can be used with capillary tube mats for radiant cooling. It is suggested that the system can also be designed as a standalone chilled water plant. As a desiccant dehumidification-based chilled water producing technology, this would expand desiccant cooling to a boarder niche application. The effects of chilled water flow rate, air distribution ratio, inlet air conditions and regeneration temperature have been analyzed in detail. Reachable handling regions, which will be helpful to system design and optimization, have been obtained.     

Experimental study on dehumidifier and regenerator of liquid desiccant cooling air conditioning system

A new type of air conditioning system, the liquid desiccant evaporation cooling air conditioning system (LDCS) is introduced in this paper. Desiccant evaporation cooling technology is environmental friendly and can be used to condition the indoor environment of buildings. Unlike conventional air conditioning systems, the system can be driven by low-grade heat sources such as solar energy and industrial waste heat with temperatures between 60 and 80 °C. In this paper, a LDCS, as well as a packed tower for the regenerator and dehumidifier is described. The effects of heating source temperature, air temperature and humidity, desiccant solution temperature and desiccant solution concentration on the rates of dehumidification and regeneration are discussed. Based on the experimental results, mass transfer coefficients of the regeneration process were experimentally obtained. The results showed that the mean mass transfer coefficient of the packing regenerator was 4 g/(m² s). In the experiments of dehumidification, it was found that there was maximal tower efficiency with the suitable inlet humidity of the indoor air. The effective curves of heating temperature on the outlet parameters of the regenerator were obtained. The relationships of regeneration mass transfer coefficient as a function of heating temperature and desiccant concentration are introduced.     

太阳能液体除湿处理热湿地区冷却顶板新风湿负荷

以广州为例分析了热湿地区冷却顶板空调系统新风冷负荷的特点,显示夏季空调期新风湿负荷占新风总负荷的90%以上.提出了利用太阳能液体除湿处理冷却顶板空调系统新风湿负荷的方案,并将其与常规的冷却除湿方案进行了比较.结果显示,冷却顶板空调系统新风湿负荷的太阳能液体除湿方式比冷却除湿方式节能40%以上,静态投资回收年限为2.2年,认为冷却顶板空调系统新风湿负荷的太阳能液体除湿方式要优于冷却除湿方式.     

The effects of operational conditions of the desiccant wheel on the performance of desiccant cooling cycles

A desiccant cooling model is developed and applied to the ventilation, recirculation, makeup, and mix modes of the operating system. The mathematical model is based on the transient coupled heat and mass transfer and is used to predict the performance of the system under various design and operational conditions. The numerical results are validated using experimental measurements. The effects of the regeneration temperature and rotational speed of the desiccant wheel on the COP and output cycle temperature are investigated. The results show the availability of an optimum regeneration temperature and rotational speed in which the output cycle temperature has a minimum value. The optimum regeneration temperature and rotational speed are detected and shown on the Psychrometric charts. Calculating these values has a significant effect on the energy use of these cycles.     

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.