Engineering solutions for polymer composites solar water heaters production

Analysis of engineering solutions aimed at a considerable decrease of solar water heaters cost via the use of polymer composites in heaters construction and solar collector and heat storage integration into a single device representing an integrated unit results are considered. Possibilities of creating solar water heaters of only three components and changing welding, soldering, mechanical treatment, and assembly of a complicate construction for large components molding of polymer composites and their gluing are demonstrated. Materials of unit components and engineering solutions for their manufacturing are analyzed with consideration for construction requirements of solar water heaters. Optimal materials are fiber glass and carbon-filled plastics based on hot-cure thermosets, and an optimal molding technology is hot molding. It is necessary to manufacture the absorbing panel as corrugated and to use a special paint as its selective coating. Parameters of the unit have been optimized by calculation. Developed two-dimensional numerical model of the unit demonstrates good agreement with the experiment. Optimal ratio of daily load to receiving surface area of a solar water heater operating on a clear summer day in the midland of Russia is 130?150 L/m². Storage tank volume and load schedule have a slight effect on solar water heater output. A thermal insulation layer of 35?40 mm is sufficient to provide an efficient thermal insulation of the back and side walls. An experimental model layout representing a solar water heater prototype of a prime cost of $70?90/(m² receiving surface) has been developed for a manufacturing volume of no less than 5000 pieces per year.     

电热水器内胆腐蚀机理及实施阴极保护综述

就电热水器内胆的腐蚀机理、阴极保护原理、阳极材料及规格的选择、安装方法等进行简要的综述。     

Effectiveness and prospects of using different solar water heating systems under the climatic conditions of the Russian Federation

The results obtained from simulating the operation of three types of solar hot water supply installations in the territory of the Russian Federation is presented: a simplest hot-water installation with accumulation of heated water directly in a solar collector and solar water-heating installations equipped with a separate storage tank and flat-plate or tubular evacuated solar collectors.     

促进新能源消纳的混合发电系统

太阳能发电功率逐日增加,以往单一的光伏发电系统并网运行的可调度性和可控性不足,提出了一种新的混合发电系统以提高调度的灵敏性.此系统包括风电场、光伏电厂、光热电站和电加热器.电加热器主要是将多余的风能、光能转化为热能并储存在太阳能发电厂的储热罐中,利用储热光热电站良好的可调度性和可控性,提高系统的旋转备用和爬坡能力,削减...     

Development of a Monte Carlo based aggregate model for residential electric water heater loads

A model for a residential electric water heater load is developed using an energy flow analysis of the water heater tank. An aggregate model for residential electric water heater loads is then developed using a rejection type Monte Carlo simulation technique. The resultant aggregate model is then used to assess the effectiveness of several demand-side management strategies using the water heater load profile presented in a previous analysis.     

高压加热器快速冷却技术的研究与应用

当高压加热器发生泄漏,机组被迫停运行进行故障抢修时,在原有热力系统设备的基础上,利用除氧器热水箱与高加标高的高度差,通过控制除氧器热水箱出水温度对高压加热器进行快速冷却。高压加热器快速冷却技术在华能南通电厂的实际应用表明,使用该技术可在较短的时间内降低加热器的金属温度,缩短加热器的冷却时间,使抢修工作提前进行,故障机组提前发电,经济效益十分显著。     

太阳能热水器防雷措施

目前国家尚未出台有关太阳能热水器防雷安装和验收标准,导致当前太阳能热水器防雷安装和验收标准不一,存在较大的安全隐患。通过对照有关规范,分析了当前太阳能热水器防雷措施存在的一些错误做法,提出一种新的太阳能热水器的防雷做法,供防雷技术人员和施工安装人员参考。     

太阳能热水器防雷现状调查及防护对策

对太阳能热水器的防雷现状进行了社会调查,并对调查情况进行了分析。对太阳能热水器的雷击原因进行了总结,阐述了河南省雷暴日数变化趋势及分布情况,提出了太阳能热水器防雷对策,并对安全利用太阳能提出了几点建议,供广大用户和防雷工作者参考。     

Design and evaluation of PV-wind hybrid system with hydroelectric pumped storage on the National Power System of Egypt

National and international policies encourage increased penetration of solar and wind energy into electrical networks in order to reduce greenhouse gas emission. Solar radiation and wind speed variations complicate the integration of wind and solar generation into power systems and delay the transition of these sources from centralized to distributed energy sources. The increased penetration of nontraditional energy sources into the electric grid stimulates the demand for large capacities in the field of energy storage. A mathematical model, which describes the operation of a proposed hybrid system, including solar PV, wind energy, and a pumped storage hydroelectric power plant is developed in this paper. This hydropower plant utilizes seawater as a lower reservoir, and only a tank has to be built in order to reduce the installation cost of the storing system. The pumped storage power plant used for compensation of the variation of the output energy from the PV and wind power plants by discharging water from the upper reservoir, which is previously pumped in the case of surplus energy from PV and wind turbine power plants. The impact of the proposed system on the grid utility is investigated in accordance with the values of energy exchange(deficits and surpluses of energy) between the considered hybrid system and the grid. The optimum design is determined by the pump and turbine capacities, upper reservoir volume, and the volume of water left in the tank for emergencies. Different scenarios of the optimum operations are presented for analysis. The results obtained from the examined scenarios indicate the ability of such a hybrid energy system to reduce the exchange of energy with the grid. This paper indicates the technical feasibility of seawater pumpedstorage hydropower plant for increasing the Egyptian national grid's ability to accept high integration of renewable energy sources.     

A novel domestic electric water heater model for a multi-objective demand side management program

This paper presents a novel domestic hot water heater model to be used in a multi-objective demand side management program. The model incorporates both the thermal losses and the water usage to determine the temperature of the water in the tank. Water heater loads are extracted from household load data and then used to determine the household water usage patterns. The benefits of the model are: (1) the on/off state of the water heater and temperature of the water in the tank can be accurately predicted, and (2) it enables the development of water usage profiles so that users can be classified based on usage behaviour. As a result, the amount of ancillary services and peak shaving that can be achieved are accurately predictable and can be maximized without adversely affecting users.     

太阳能热水器安装避雷针问题的探讨

阐述了雷击太阳能热水器的机理以及避雷针安装高度,避雷针与太阳能热水器之间安全距离的计算方法。分析了避雷针安装方位、冲击接地电阻、建筑物高度对避雷针高度的影响,并给出了避雷针与太阳能热水器间距不满足时的处理方法。指出正确安装避雷装置对减少雷击带来的损失的重要性。     

用于消纳风电的城区用户电热水器负荷群滑模控制策略研究

居民电热水器是一种典型的热储能负荷,用电产生的热水具有热存储性,可以消纳波动性风电。提出了用于消纳风电的电热水器负荷群滑模控制策略,来实时控制电热水器负荷群。控制率与电热水器群数量、热水使用情况等相关,对于消纳风电具有较强的鲁棒性。采用某城区居民区电热水器负荷群的仿真研究表明,提出的电热水器群滑模控制策略能有效消纳风电,验证了电热水器负荷群滑模控制策略有效性。     

Heat Pump Water Heater Control

A control system is described for a heat pump water heater which uses the thermostat on an existing electric water heater to determine the need for water heating. The control system allows an installer to wire in an electric water heater with the heat pump using the same connections for supplying power to the water heater which would normally be used. This control system will also automatically turn off the heat pump when frost forms on the evaporator coil and will allow the electric elements in the tank to heat the water. The system is easy to install, provides reliable operation of a heat pump, does not create any unusual safety problems, and gives uninterrupted hot water service.     

基于AVR单片机和PID算法的水温控制器

文中介绍在水族箱加热棒HA168基础上扩展而成的温度实时控制系统.该系统以水温为主要参数,控制核心为高档8位单片机ATmega128,采用PID算法,更加合理地控制水温.单片机控制系统自动运行,并且能够与PC机进行通信和状态设定,上位机程序采用图形化编程语言LabVIEW编写.经过实际运行,能够较好地控制水温.该模块也可以应用于其他的温度控制场合.     

Evaluation of jacket materials and configurations and effect ofmoisture absorbing materials on preventing water tree growth in powercables

Polymer insulated medium voltage cables have experienced premature failures in-service, due in large part to water treeing. Research has shown that the initiation sites of these water trees are often located where there are stress enhancements at the insulation/semiconducting shield interface and where water soluble contaminants permeate into the insulation. Material suppliers, cable manufacturers and users have introduced improved materials and cable designs as well as processing, manufacturing, transport, storage, and installation techniques that minimize contamination. Despite these advancements, gradual contamination can still occur due to the diffusion of ground water into the insulation. In fact, certain contaminants that are carried through the semiconductor/insulation shield interfaces tend to promote water tree growth. Manufacturers are now beginning to recognise this problem and have suggested the use of moisture resistant cables with jackets made of PVC, polyethylene or metal/polymer laminates along with underjacket water absorbing materials. This paper discusses the effectiveness of different jackets and materials and presents data on the effectiveness of water absorbing materials in delaying water permeation into the insulation. A simple and efficient cable-cell technique was developed which monitored the effectiveness of complete cable designs, by measuring the long-term water permeation resistance of short lengths of distribution class cables     

风光互补的压缩空气储能与发电一体化系统特性分析

提出一种新型的风光互补的储能与发电一体化系统,该系统互补利用风能与太阳能,并通过压缩空气储能系统改善其不稳定性与间歇性,实现储能与发电等多功能集成;基于热效率、火用效率及储能效率3种评价准则,全面分析系统的热力特性和储能特性,揭示透平进口压力和初温、压气机和透平效率对系统性能的影响规律;分析比较了系统采用等容储气罐和等压储气罐对性能的影响,指出利用等压储气罐能有效提高系统热力性能和储能性能。研究结果为可再生能源的规模化发展以及大规模储能的发展提供了参考。     

氢经济面临的机遇和挑战

从氢的生产、储运和应用三个方面概述了氢经济面临的机遇和挑战:氢的生产技术有化石燃料重整、太阳能制氢、生物制氢、热能制氢等;储氢方式和储氢材料有高压气瓶储氢、固体储氢材料(主要是金属和复合氢化物材料、纳米结构材料);氢的应用方面主要介绍了两种燃料电池技术,质子交换膜燃料电池和固体氧化物燃料电池。人类在这些方面已取得很大的进展,但是人类离氢经济的实现尚有不小的距离。发展可持续的制氢技术、高密集的储氢材料和先进的燃料电池技术是实现氢经济的关键。最后指出实现氢经济对中国的意义更大。     

计及高阶方程分段线性化的港口电-氢综合能源系统优化调度

现有电-氢综合能源系统模型存在制氢、储氢装置模型不准确的问题，影响了系统运行调度的安全性。考虑储氢装置内氢气在高压状态下温度-压强的动态特性，建立港口电-氢综合能源系统优化调度模型。通过电解水制氢技术储存风光发电多余的电能，在此基础上协调电力和氢气的负荷需求，有效地提高了新能源利用率并保证了系统的安全稳定运行。对高压储气罐的温度-压强高阶非线性模型进行分段线性化处理，在保障较高精度的同时大幅提高了求解效率。典型港口综合能源系统算例验证了所提方法的有效性。     

直膨式太阳能热泵热水器实验研究及经济性分析

直膨式太阳能热泵热水器(DX-SAHPWH)的运行经济性除与系统本身的结构和性能相关之外,还与多种因素有关。建立了直膨式太阳能热泵热水器样机的集总参数法模型,并在上海的气候条件下进行了实验验证。根据全国典型气候地区的气象参数模拟系统运行的耗能情况;用综合能源价格法分析了影响系统经济性的关键因素,并将样机与几种传统热水器的全年运行情况进行了比较。分析表明,气候条件、能源价格对比以及运行控制策略是影响系统运行节能性和经济性的主要因素。     

含大规模风电及光热电站的电力系统优化调度方法

含储热和电加热的光热电站的出力具有良好的灵活性和可调度性,能够有效提升电力系统调节水平和新能源消纳能力。首先,基于光热电站运行机理,建立含储热及电加热的光热电站运行模型,描述光热电站的能量转换特性及运行约束。进而,以系统运行成本最优为目标,计及系统各项运行约束,建立含大规模风电及光热电站的电力系统优化调度模型,并利用优化软件CPLEX求解模型。该模型综合考虑光热电站提供备用容量能力、系统运行稳定性及整体经济性,从而确定最优日前调度策略。最后,通过IEEE 39节点系统算例仿真验证了该方法的可行性和有效性。