浅谈太阳能热水器与建筑结合的几种方式

随着全国各地太阳能与建筑结合图集的颁布与实施,太阳能热水器的推广应用范围不断扩大,各地已成功地建设了一批太阳能热水器与建筑应用结合的试点工程,同时也加强了太阳能热水器与建筑结合的管理。但是,当前太阳能热水器与建筑的结合仍存在许多问题,如：太阳能热水器系统不完善,太阳能热水器与建筑结合不紧密,     

太阳能热水器与建筑结合所面临的几个问题

太阳能热水器与建筑一体化在业内已经成为大家关注的热点问题。根据我这几年工作的体会,如何将太阳能热水器同建筑结合在一起是一件非常艰难和烦琐的事情。要实现太阳能热水器和建筑一体化会面临很多的障碍因素,而且有很多的困难是要我们去克服的,还需要一定的时间和精力才能达到我们所考虑的一个基本目标。从科技部的角度讲,这几年围绕这项工作,在广泛征求部门和专家意见的基础上,初步地进行了一些安排和考虑,总结出来,主要有以下几个问题。第一个就是太阳能热水器产品的技术更新换代问题。我们国内太阳能热水器生产厂家号称上千家,堪称世…     

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…     

太阳能热水器与建筑一体化

阐述了太阳能热水器与建筑一体化建设发展现状及存在的问题。在综合分析的基础上提出了建议和对策。     

加快太阳能热水器在住宅建筑中的应用

介绍了太阳能热水器在建筑工程配套建设中的现状,叙述了太阳能热水器在住宅建筑中应用时的设计标准化,安装规范化问题,并提出单户式安装和单元式安装的构想。     

福建省太阳能热水器与建筑一体化问题的思考

太阳能热水器与建筑相结合 ,成为建筑节能的一个构件 ,是今后太阳能热水器发展的必然趋势。与电热水器、燃气热水器相比 ,太阳能热水器与建筑相结合所涉及的因素更为复杂 ,有许多问题值得我们去研究、分析与思考     

一种阳台式太阳能热水器

１阳台式太阳能热水器技术现状近几年，随着城镇建设的发展，城建管理部门对建筑的造型十分重视。许多大中城市陆续出台了建筑屋顶“平改坡”政策，对现有楼顶平面进行坡面改造，并停止新建平顶建筑项目的审批，实行了商品房顶层阁楼配售的措施，这些情况对于传统热水器的销售和安装带来一定困难。针对这一问题，太阳能热水器生产开发厂商已经把注意力放在了太阳能与建筑结合的问题上来，并提出了许多方案，其中分体阳台式太阳能热水器就是其中较为可行的方案之一。目前，阳台式太阳能热水器产品尚存在以下问题。（１）成本高，故障率高现有…     

德国太阳热水器与建筑的结合

德国太阳热水器与建筑的结合马丁·雷斯近年来，太阳集热器的应用在德国有较快的发展，根据政府机构的统计和预测，１９９０年德国已安装了２８．４万ｍ２太阳热水器，平均每千人拥有集热器面积为３．６ｍ２，市场销售额约合３．４亿人民币，到本世纪末，集热器的安装面积...     

福建省太阳能热水器与建筑一体化问题的思考

太阳能热水器与建筑相结合，成为建筑节能的一个构件，是今后太阳能热水器发展的必然趋势与电热水器，燃气热水器相比，太阳能热水器与建筑相结合所涉及的因素更为复杂，有许多问题值我们去研究、分析与思考。     

光控非承压分体式太阳能热水器设计及应用

光控非承压分体式太阳能热水器利用光照强弱及持续时间自动控制水流的无压力循环、回流,采用集热管底部进水,集热管与水直接进行热交换,较好地克服了一体式太阳能热水器的集热管易结垢、水箱保温性能差、使用范围窄及承压分体机易泄漏、价格昂贵等缺点,采用微压传感器实时控制各种用水需要,避免了承压分体机所采用的冷水顶热水方法的局限性。通过对整机的结构、工作原理、控制程序及应用实例的详细论述,阐明了该机不仅具有承压分体机的广泛适应性,而且具有非常高的性价比和极低的自身能耗。     

Transient analysis of a solar air heater of the second kind

This paper presents a theoretical analysis along with the experimental validation study of a solar air heater of the second kind. The heater consists of a flat passage between two metallic plates through which the heat transfer fluid air is made to pass by some auxiliary means. Study of the periodic response of different parameters of this solar air heater is attempted. The heat balance equations governing the behaviour of the system are solved explicitly. The results obtained from the analytical expressions for the transient variation of outlet air temperature compare well with experimental data. Predictions are also made regarding effects of different performance parameters of the air heater with variations of air mass flow rate and plate emissivity with the hope of optimizing the collector configuration.     

A solar water heater with a built-in latent heat storage

In this paper, we have investigated the performance of a novel built-in storage type water heater containing a layer of PCM-filled capsules at the bottom. The PCM layer is introduced with a view of getting hot water during off-sunshine hours. The moving solid-liquid boundary layer problem for the PCM material is simplified to a stationary boundary layer problem, and the effect of latent heat is included in the specific heat by replacing the semi-melted PCM by a fictitious solid. The performance of the water heater is then predicted analytically for two depths of PCM and for different flow rates, both constant and intermittent. The case of sudden withdrawal of water over very short periods is also studied.     

The performance of a cylindrical solar water heater

A cylindrical solar water heater is designed and manufactured in the Department of Mechanical Engineering, University of Bahrain. It consists of a cylindrical tube made from high quality glass having a length of 0.8, 0.14 m outer diameter and a thickness of 6 mm. A copper coil tube in the shape of spiral rings, with the tube inner diameter of 2 mm and outer diameter of 3.175 mm, painted black, serves as a collector to the incident solar energy on the cylinder wall. The thermal performance was evaluated extensively throughout the months of March and April 2002; a maximum temperature difference of 27.8 °C between inlet and outlet of the solar water heater at a mass flow rate of 9 kg/h was achieved. The efficiency of the cylindrical solar water heater was calculated. The maximum value during the experimental period was found to be 41.8%. This reveals a good capability of the system to convert solar energy to heat which can be used for heating water. An economic analysis has reveals that the cylindrical solar water heater compared with the flat plate collector is cost effective.     

Refrigerant-charged integrated solar water heater

The performance of two R-11-charged integrated solar water heater collectors was investigated experimentally for forced and natural circulation water flows. The heat transfer from the refrigerant loop to the hot water storage tank took place through a condenser of novel design integrated within the collector frame. The effect of the condenser inclination on the system efficiency was remarkable for natural circulation water flow but had no significant effect for forced circulation flow. The difference in thermal response between the refrigerant and water loops caused buildup of stored energy in the condenser. This energy affected the buoyancy forces and generated flow pulsation that caused a harmonic-like variation of the system efficiency. This effect vanished with forced water circulation flow. The system efficiency varied between 20 and 50% depending on the solar insolation.     

分体式家用太阳热水器

指出了传统太阳热水器存在的一些问题,为克服太阳热水器在高层建筑应用中受到的限制,研制了 一种靠重力循环的分体式家用太阳热水器。在冬季,用集中供暖系统中的热水为辅助热源加热蓄热水箱中的 水,以解决仅利用太阳能加热供水温度太低的问题,与利用辅助电加热相比,可降低运行费用。     

家用太阳热水器与太阳热水系统的技术经济比较

分析了户用太阳热水器和太阳热水系统工程的经济技术特点,对两者成本构成、项目财务净现值、投入回收期和财务内部收益率等有关指标进行了经济技术比较.分析比较表明,太阳热水系统与家用热水器相比,节省安装占地,与建筑相结合得好,在降低成本,缩短投资回收期,提高经济效益方面有明显的优势.     

The effect of plane booster reflectors on the performance of a solar air heater with solar cells suitable for a solar dryer

We present a theoretical study of a solar photovoltaic-thermal (hybrid) system consisting of a flat-plate solar air heater mounted with solar cells and a plane booster. A conventional flat-plate collector is converted into a hybrid system by mounting solar cells directly on the absorber plate. A hybrid system is self-sufficient in the sense that the electrical energy required by the pump is supplied by the panel. Such systems are well suited to applications such as solar drying. The combined system is analysed for the case when the radiative and absorptive properties of the cell surface and the absorber plate are nearly the same. The solar cell efficiency is a linearly-decreasing function of the absorber plate temperature. The performance of the system has been evaluated for various combinations of boosters. The minimum area of the solar cells required to run the pump at a given flow rate has been calculated as a function of time, with and without boosters. The minimum cell area required decreases with the use of boosters. High cost cells may be replaced by low cost reflectors. The solar air heaters presently available on the market are not suitable for direct conversion to hybrid systems.     

Analysis of exergetic performance for a solar air heater with metal foam fins

In this experimental study, an exergetic analysis is presented for solar air heaters (SAHs) that have absorber plates equipped with different fin arrangements. The following two types of fins were used: solid fins (conventional) and metal foam fins. Longitudinal, staggered, and corrugated fin arrangements in SAHs were investigated under the weather conditions experienced in Baghdad, Iraq in February to April 2018. The exergy efficiency and exergy loss of the SAHs were evaluated for five air mass flow rates ranging from 0.011 to 0.059 kg/s. Based on the exergy analysis, SAHs with metal foam fins are more efficient than those with solid fins. In addition, corrugated metal foam fins introduce more turbulent flow than the other fin configurations. It was found that the exergy loss and the exergy efficiency were directly proportional to the values of solar irradiance and air mass flow rates. At solar noon, the maximum values for exergy change were 127 and 89 W/m² for air mass flow rates of 0.011 and 0.059 kg/s, respectively.     

Modelling the thermosiphonic solar water heater with draw-off

A model of the time-dependent behaviour of the solar water heating system with natural circulation is modified to include the effects of water draw-off. Through computer simulation, the model is used to study the influence of the draw-off starting temperature T_s and the draw-off rate m_d on the overall system efficiency. Hot water withdrawal is assumed continuous from the moment the tank mean temperature reaches T_s. The results presented show that efficiency increases as T_s is decreased and/or m_d is increased. However, the draw-off parameters should be optimized in relation to the collector area and the tank volume for the location considered.