分离式双循环太阳热水系统

目前备受太阳能界和建筑界关注的一个焦点课题则是随意安装的紧凑直插式太阳热水器已经严重地破坏了建筑外观,尤其是在斜屋顶上的安装如图1所示。以至于部分旅游城市如大连、青岛曾一度限制太阳热水系统的安装。分离式双循环太阳能热水系统(图2)则可以完全解决以上的各种问题。如图3～图5所示分离式双循环太阳热水系统已经可以与整个建筑融为一体了,尽管安装位置、朝向、角度各异。     

分离式太阳热水系统

这些年，全玻璃真空太阳集热管以及以它为核心元件的热水系统在我国市场得到了广泛推广，主要优点在于增加了太阳能的全年使用天数，尤其是方便了北方地区冬天使用。但是这类热水系统存在的最大缺点是系统非承压，而且不容易和建筑尤其是屋顶结合，建筑师们认为破坏立面和屋顶效果。     

燃气锅炉与太阳热水系统结合的实例

通过解决工程实例中的管路热损问题,探讨太阳热水系统与燃气锅炉结合使用的工程方案。     

太阳能热利用与建筑结合技术讲座(二)太阳热水系统

1 太阳热水系统的分类，太阳热水系统通常由集热器、贮水箱、连接管路、辅助加热器、控制器等部件组成。太阳热水系统的种类很多，在此仅介绍两种太阳热水系统的分类方法：一种是按系统的特征分类，另一种是按其在建筑中应用和运行的特点分类。     

双直流太阳热水系统

长久以来,太阳热水器及太阳热水系统工程有三大难题,像瓶颈一样困扰着太阳能热利用技术的普及与发展,它们是：１）太阳热水器（系统）如何防冻抗冻？２）如何与建筑物完美地结合？３）如何做到“全天候”供热水？由于它们的存在,使得太阳热水器在价格上和市场份额上都无法和常规能源（电、油、气）热水器进行竞争。常规能源热水器往往到了普及率达到６０％～７０％时才出现价格大战、成本价倾销的现象,而太阳热水器全国家庭普及率只有３％、４％就出现了价格大战,售价一年比一年低,利润空间愈来愈小,业内业外竞争态势十分严峻。指望…     

安徽省制订住宅建筑-太阳热水系统一体化设计安装与验收标准

1工作简况本项目是根据1999年安徽省政府农村能源领导小组第10次办公会议要求和深入贯彻执行《安徽省农村能源建设与管理条例》,受安徽省建设厅委托开展的。鉴于目前该项标准在国内外尚属空白,有一定难度。安徽省农村能源技术推广总站从实际出发,组织了本站和安徽省能源工程设计研究所的精干技术人员参加编制,挑选了本省一些有实践经验的太阳热水器生产企业和经销商的技术人员参加协作。经过两年多的努力,通过调研、考察,查阅了国内外相关技术资料,邀请有关方面的专家专题研讨、论证,几经修改,完成了本标准的编制工作。2002年8月13日,标准通…     

浅谈我国太阳热水器与建筑的结合

这个问题是近年来的热门话题，事实上，也是太阳能界与建筑业界２０多年来共同的热切希望，也是广大人民群众呼声日益高涨的迫切需要。常年能够利用热水作为生活用水，可以说是生活质量获得显著改善和提高的一项重要标志。但是在过去的１／４个世纪中，由于思想观念、设计水平和生产技术等诸多原因，太阳能界和建筑业界之间存在着相当明显的差异，主要表现在以下几个方面。１思想观念：太阳能界从事热利用的人员对于建筑业界的常规要求不大了解，总局限于认为只要尽量改进热水器的类型和材质选取、生产技术、工艺水平并提高实际有效的得热量…     

承压分离式太阳能热水系统储热水箱中螺旋盘管换热器的分析设计

阐述了分离式太阳能热水系统的运行原理,盘管式储热水箱的优点,并着重分析了盘管换热水箱内盘管换热器的设计步骤,包括设计参数的选择、热计算、结构设计和流动阻力计算等,为有类似工程设计的有关人员提供参考。通过一系列的设计计算与校核,证明本热力设计符合要求,并能完全满足热水系统的设计要求。     

全国太阳热水系统工程、家用太阳热水系统国家标准培训即将开班

中国拥有世界上最大的太阳能热水器市场和成熟的太阳能热水器行业。近年来，太阳热水工程市场急速发展，也暴露出太阳能热水系统市场发展中存在的一些问题和矛盾，其中缺乏适当的标准和有效的监管而带来的恶性市场竞争，不少工程达不到国家标准，工程质量难以保证，造成用户的很大损失，制约着太阳能热水器行业的蓬勃发展。为规范太阳能产业的发展，促进太阳能产品的研发和市场的开拓。根据广大太阳能热水器企业和工程投标需要和要求，为进一步提高热水工程质量，保障我国太阳能行业持续健康发展，特举办太阳热水系统工程、家用太阳热水系统国家标准资质培训班。具体事宜通知如下：     

国内外家用分离式太阳能热水系统浅析

通过国内外分离式太阳能热水系统形式及部件对比,阐述了国内外分离式太阳能热水系统的差异。     

Optimization of the heat exchanger in a flat plate indirect heating integrated collector storage solar water heating system

Due to the environmental impact of energy usage, consumers need to be encouraged to use renewable energy sources such as solar energy. The indirect heating flat plate integrated collector storage solar water heating system is one of the compact systems for domestic water heating. It incorporates the collection of a solar energy component and a hot water storage component in one unit. The objectives of this study were to investigate the effect of different parameters on the thermal performance of this system with the aim of reducing both the initial and the running costs. The outlet service water temperature was used as a measure of performance, because it is an indicator of the energy acquired from the solar radiation. The continuity, momentum and energy equations of the fluids involved in the system were numerically solved in a steady state condition, using FLUENT software. Three-D CFD models were developed and validated using previous experimental results. A standard k–ω turbulent model was used in the optimization of the heat exchanger because it produced good agreement with the experimental results. The surface-to-surface radiation model was included. The effect of single and double row heat exchangers with different lengths was investigated. Circular and elliptic cross-section pipes were also examined. Mass flow rates of 500 and 650 L/h were chosen. The results showed that the single row HX of 10.8 m length for both the elliptical and type B tube gave high service water outlet temperature (acceptable for heat exchanger design) and with low pumping power. This resulted in an increase in the thermal efficiency and a significant reduction in both the initial and the operating costs of the system.     

High temperature solar heated seasonal storage system for low temperature heating of buildings

A preliminary study of a solar-heated low-temperature space-heating system with seasonal storage in the ground has been performed. The system performance has been evaluated using the simulation models TRNSYS and MINSUN together with the ground storage module DST. The study implies an economically feasible design for a total annual heat demand of about 2500 MWh. The main objective was to perform a study on Anneberg, a planned residential area of 90 single-family houses with 1080 MWh total heat demand. The suggested heating system with a solar fraction of 60% includes 3000 m² of solar collectors but electrical heaters to produce peak heating. The floor heating system was designed for 30°C supply temperature. The temperature of the seasonal storage unit, a borehole array in crystalline rock of 60,000 m³, varies between 30 and 45°C over the year. The total annual heating costs, which include all costs (including capital, energy, maintenance etc.) associated with the heating system, were investigated for three different systems: solar heating (1000 SEK MWh⁻¹), small-scale district heating (1100 SEK MWh⁻¹) and individual ground-coupled heat pumps (920 SEK MWh⁻¹). The heat loss from the Anneberg storage system was 42% of the collected solar energy. This heat loss would be reduced in a larger storage system, so a case where the size of the proposed solar heating system was enlarged by a factor of three was also investigated. The total annual cost of the solar heating system was reduced by about 20% to about 800 SEK MWh⁻¹, which is lower than the best conventional alternative.     

Performance of a non-metallic unglazed solar water heater with integrated storage system

The performance of a new design of non-metallic unglazed solar water heater integrated with a storage system has been studied. In this system, the collector and storage were installed in one unit. All parts of the system have been fabricated from fiberglass reinforced polyester (GFRP) using a special resin composition that provides good thermal conductivity and absorptivity. The storage tank has a capacity of 329 l. The design of the storage system was sandwich construction, with the core material made out of polyurethane foam, which combines stiffness and lightness of structure with very good thermal insulation. The width and length of the absorber plat were 1.4 and 1.8 m, respectively. The performance of the system has been investigated by two methods. In the first method, the storage tank was filled up with water the night before the test. The tank was then drained during the night, refilled and made ready for the next day’s test. The tests were repeated under varied environmental conditions for several days. The maximum water temperature in the storage tank of 63 °C has been achieved for a clear day operation at an average solar radiation level of 700 W m⁻² and ambient temperature of 30 °C. The decrease of water temperature with and without the thermal diode is 10 and 20 °C, respectively. In the second method, the testing was of the same way, but in this case without draw-off or draining of the hot water from the storage tank. All data readings were recorded from sunrise to sunset over the same period. The temperature was recorded for several days and ranges of 60–63 °C were obtained in the storage tank. A system efficiency of 45% was achieved at an average solar radiation level of 635 W m⁻² and ambient temperature of 31 °C.     

Roof integrated solar heating system with glazed collector

Solar space heating is a proven effective method to reduce conventional energy requirements for domestic heating. However producing a low cost collector design which is commercially viable has been difficult. Research has been conducted into using a corrugated steel roof to function as an unglazed air collector. This research revealed that, although economical, due to the low performance of such a collector it was doubtful that the system could deliver meaningful energy savings. As such investigations have been made into glazing the collector with a low cost commercially available glazing material. A mathematical model of the glazed collector and the system have been developed. The model indicated that, with a glazed collector, the system performance significantly improved and used less conventional energy than a standard heat pump and gas heater under standard winter conditions in Adelaide Australia. Glazing was found to improve the cost effectiveness of the system but further work was needed to deliver higher energy savings.     

Thermal performance of PCM thermal storage unit for a roof integrated solar heating system

The thermal performance of a phase change thermal storage unit is analysed and discussed. The storage unit is a component of a roof integrated solar heating system being developed for space heating of a home. The unit consists of several layers of phase change material (PCM) slabs with a melting temperature of 29 °C. Warm air delivered by a roof integrated collector is passed through the spaces between the PCM layers to charge the storage unit. The stored heat is utilised to heat ambient air before being admitted to a living space. The study is based on both experimental results and a theoretical two dimensional mathematical model of the PCM employed to analyse the transient thermal behaviour of the storage unit during the charge and discharge periods. The analysis takes into account the effects of sensible heat which exists when the initial temperature of the PCM is well below or above the melting point during melting or freezing. The significance of natural convection occurring inside the PCM on the heat transfer rate during melting which was previously suspected as the cause of faster melting process in one of the experiments is discussed. The results are compared with a previous analysis based on a one dimensional model which neglected the effect of sensible heat. A comparison with experimental results for a specific geometry is also made.     

阳台式太阳能热水系统性能及分析

对阳台式太阳能热水系统进行了应用效果的测试:当太阳辐射量为17 MJ/m2时,太阳能集热系统单位轮廓采光面积的日有用得热量为4.73 MJ/m2,小于评定合格值;热水系统温升为20℃,小于评定合格值;贮水箱保温性能△t sd为6.2℃,符合评定合格值,水箱保温良好;贮水箱最终出水温度达到51℃,能满足配水点最低水温要求。分析表明,造成阳台式太阳能热水系统集热效果达不到合格标准是由于集热器安装倾角过大、上下层集热器的自遮挡和建筑的隔墙遮挡所致。文章提出,应用在高层建筑的集热器可分散设置在屋顶和南向外墙的外挑板上,并采取上下错层的布置方式。     

高太阳能保证率的太阳能热水系统

介绍了一种高效节能的太阳能热水系统,并分析了该系统的工作原理.本系统的设计核心是提高太阳能热水系统的太阳能保证率,及与常规热水器相比节能率fr.     

太阳能采暖系统的基本类型

在第一讲介绍太阳能供热采暖系统分类的基础上,本讲着重讨论其中最基本的液体集热器太阳能采暖系统、空气集热器太阳能采暖系统和低温热水地板辐射太阳能采暖系统.     

Design and assessment of a solar energy based integrated system with hydrogen production and storage for sustainable buildings

The current study investigates a holistically developed solar energy system combined with a ground-sourced heat pump system for stand-alone usage to produce power, heat, and cooling along with domestic hot water for residential buildings. An integrated system is proposed where three types of building-integrated photovoltaic plant orientation are considered and integrated with a vertical-oriented ground-sourced heat pump system as well as an anion exchange membrane electrolyser for hydrogen-based energy storage along with proton exchange membrane fuel cells. The ground-sourced heat pump system covers the heating requirements and exploits the available thermal energy under the ground. Hydrogen subsystem enables the integrated system to be used anytime by compensating the peak periods with stored hydrogen via fuel cell and exploiting the excess energy to produce hydrogen via electrolyser. The photovoltaic plant orientations are extensively designed by considering geometries of three different applications, namely, rooftop photovoltaic, building-integrated photovoltaic façade and photovoltaic canopy. The shading and geometrical losses of photovoltaic applications are extensively identified and considered. In addition, the openly available high-rise building load profiles are obtained from the OpenEI network and are modified accordingly to utilize in the current study. The building requirements are considered for 8760 h annually with meteorological data and energy usage characteristics of the selected regions. The integrated system is assessed via thermodynamic-based approach from energy and exergy points of views. In order to increase generality, the proposed building energy system is analyzed for five different cities around the globe. The obtained results show that a 20-floor building with approximately 62,680 m² residential area needs between 550 kWp and 1550 kWp of a photovoltaic plant in five different cities. For Ottawa, Canada, the overall energy and exergy efficiencies are found as 18.76% and 10.49%, respectively, in a typical meteorological year. For the city of Istanbul in Turkey, a 20-floor building is found to be self-sufficient by only using the building's surface area with a 495 kWp BIPV façade and a 90 kWp rooftop PV.