基于TRNSYS的空气源热泵辅助太阳能热水系统优化研究

为实现空气源热泵辅助太阳能热水系统中关键参数的优化匹配,基于TRNSYS动态模拟平台建立完整的空气源热泵辅助太阳能热水系统模型。以系统生命周期成本为目标函数,以集热器面积、集热器倾角、水箱容积及热泵功率为优化变量,借助GENOPT软件调用Hooke-Jeeves算法对系统各变量进行同步优化,并对各优化变量进行敏感性分析。以西昌市某学生宿舍的空气源热泵辅助太阳能热水系统为研究对象进行优化。研究结果表明,优化后的COPsys普遍提高,系统性能得到明显改善,系统全年运行费用缩减,全年节电率高达9.11%。并在此基础上提出关键参数的推荐匹配原则:单位集热面积水箱容积为70 L/m~2,单位集热面积热泵功率为60 W/m~2,最佳集热器倾角为φ-6°(φ为当地纬度)。对空气源热泵辅助太阳能热水系统进行设计时,可依据以上匹配原则对热泵功率、集热器面积、水箱容积、集热器倾角按照先后顺序进行优化。研究结果可为空气源热泵辅助太阳能热水系统的优化设计提供理论依据。     

高层住宅建筑南立面太阳能热水系统水量配比特性研究

利用日均太阳辐射模型与集热器能量输出模型对平板型和真空管型太阳能热水系统水量配比进行建模分析。结果显示,模拟的水量配比与实验测试吻合较好,相对误差在10%以内。基于我国五大气候分区133个城市的气象数据,利用此模型对集热器件与建筑南立面大角度(70°～90°)集成后的太阳能热水系统的水量配比进行模拟计算与分析。为便于工程应用,利用多项式线性回归技术对水量配比与气象参数间的关系进行回归分析与整理。给出各类气候区夏半年和冬半年太阳能热水系统水量配比与气象参数间的回归关系式,为太阳集热器件与建筑南立面大角度集成的水量配比的优化提供方便。     

安装太阳能热水器有关数据的选取

集热器安装倾角及热水贮水箱容量的选取是影响太阳能热水器热效率的两个外在的主要因素,合理的选取上述两个数据可以增加系统的热效率,下面介绍的是几个数据直接选取的方法: 1.集热器安装倾角的选取(β),如图所示不同季节太阳能的高度不同,因而对于不同春秋季节使用的太阳能热水器,其安装倾角也应不同。     

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。     

太阳能热水系统集热器面积与倾角的组合优化

集热器面积与倾角是太阳能热水工程设计中的重要参数。综合考虑气候、用水方式、太阳辐射和热水负荷的季节性等因素,建立完整的组合优化计算模型,在合理年太阳能保证率的前提下确定集热器面积,以年辅热量最小的原则确定与集热器面积相配的倾角,并以3个城市为例进行计算。结果表明,当太阳辐射与热水负荷变化趋势相反,最佳倾角随集热器面积增加而增大;当太阳辐射与热水负荷变化趋势相同,最佳倾角随集热器面积增加基本不变。     

太阳能-空气源热泵热水系统多水箱设计方案的优化与能效分析

该文针对高校宿舍热水系统，为提高其经济效益与减排效果提出加入夜间蓄热水箱和热泵机组缓冲水箱的两种多水箱太阳能-空气源热泵热水系统，分别设计优化运行策略。选取水箱体积、集热器面积、倾角以及热泵功率等参数为优化变量，并确定生命周期成本年值与全年运行碳排放量为目标函数，通过对单水箱、双水箱和三水箱热水系统在逐月电耗、电费、太阳能保证率以及平均系统COP等方面的研究与分析，发现三水箱热水系统比传统单水箱全年能节省电耗约3.86%，省电费22.35%，太阳能保证率提高33.32%，平均系统COP提高45.70%，生命周期成本年值降低5.07%，碳排放量减少3.72%，效率提升4.65%。     

蓄热水箱的热分层研究进展

太阳能热水系统中蓄热水箱热分层的研究,已经成为目前提高太阳能集热器效率和太阳能保证效率的重要方向,良好的热分层一方面可以降低进入集热器的温度,减少传热损失,提高集热器效率;另一方面可以提高水箱内可被利用的高温水量,减少辅助加热量,从而提高整个太阳能热水系统的性能。综合国内外文献,总结了蓄热水箱热分层现象,热分层的数学模型以及影响因素,并展望了热分层蓄热水箱的研究趋势。     

太阳能电热水系统集热器阵列布置优化

综合考虑集热器倾角、方位角、间距等因素,确立了安装在水平面上有限面积内太阳能集热器阵列得热量与地理位置及集热器布置方式之间的关系,基于上述关系又建立了太阳能电热水系统全年辅助加热量计算模型及系统全年用电成本计算模型。最后,文中以太阳能电热水系统用电成本最低、辅助加热量最小为目标确定太阳能集热器阵列的最优布置。研究结果表明:当阵列得热量最大时,系统年辅助电加热量最小,系统的耗电成本也最低。以某高校男生宿舍楼为例,在宿舍楼楼顶平面500m2的区域按照集热器阵列最小维护间距为0.5m的规范布置集热器,最优设计方案为:阵列排数为8排,阵列倾角为、阵列方位角为,此时系统全年辅助加热量为128943MJ,全年系统辅助加热电耗成本为2.45万元。     

太阳能光伏光热系统集热器连接方式的优化

集热器连接方式对强制循环式光伏光热(PVT)热水系统的运行性能存在较大影响,针对最佳连接方式的相关研究未见报道。综合考虑环境温度、太阳辐射量和热水负荷等因素,以12块平板型PVT集热器(2 m×1 m)为研究对象,利用Fortran语言建立不同连接方式PVT热水系统动态传热模型,并分别以发电量、实际集热量以及实际综合发电量为优化目标进行计算。结果表明:在两种不同工况下,获得最大发电量的连接方式都为N=1,而获得最大实际集热量的连接方式并不一致;综合全年性能分析,以发电量、实际集热量和实际综合发电量为优化目标时对应的最佳连接方式和最佳倾角组合形式分别为:N=1和β=20°,N=4和β=28°,N=3和β=26°。研究结果对大型太阳能集热器安装方式的选取具有参考价值。     

基于能量分析和分析的太阳能热泵系统优化研究

以热力学第一、二定律为基础,对太阳能热泵系统的各主要部件进行分析,给出系统各环节的能量分析模型和分析模型。选取北京某典型别墅作为太阳能热泵系统的应用对象,模拟系统效率随太阳能集热器面积和储水箱体积的变化,获得相应参数的最佳配比。结果表明:COP分析和代价效率分析一致,系统在集热器面积为127.98 m~2,水箱体积为9.08 m~3时达到最优;集热器面积为127.98 m~2,水箱体积为3.936 m~3时系统效率最大。     

Prediction of evaporation of defrosted water in refrigerator water trays

The main concern of the present paper is to simulate the evaporation of defrosted water in domestic refrigerator water trays. The tray is assumed to be located above in vicinity to the compressor head, and part of the heat used to evaporate the water is heat from the compressor. The mathematical model is based on that of Bansal and Xie. In modeling, the basic physical equations are conservations of mass and energy. The model includes the various relevant parameters, e.g., the ambient air temperature, relative humidity of ambient air, initial temperature of defrosted water, area of water tray, initial mass of water in the tray, and characteristic length and area of the compressor shell. The experiments are done in two steps: finding of the correlations between the temperature of the compressor shell and the elapsed time and verifying the simulation results. The results show that the model simulates the experimental data fairly well. The model may be used as a tool to determine a suitable configuration for the evaporation of defrosted water collected in domestic refrigerator water trays.     

Use of controlled water circulation in tap water heat pumps

Condensers used in tap water heat pumps are either of the integrated passive immersion type or separate units with active water circulation. The use of the active circulation configuration together with a counter-flow condenser and water flow control has a number of advantages compared to passive immersion condensers. In particular, hot water temperatures above the saturation temperature of the condensing refrigerant are possible. The counter-flow arrangement also permits sub-cooling gains in cycle efficiency. These two features offset the pumping power penalty which would not be necessary in a system with a passive immersion condenser.     

焦化厂实行梯级用水降低水耗的实践

通过对焦化厂所用水水质和不同用水系统工艺特点的分析，制订焦化厂梯级用水制度，降低水耗30％；对水处理设备进行改进，稳定水处理药剂浓度；根据阻垢及缓蚀实验结果，确定适用于高氯离子浓度循环水系统的阻垢缓蚀剂。     

A novel thermal water pump for circulating water in a solar water heating system

This research purpose was to perform a parametric study of a novel thermal water pump well fitted in a simulated solar water heating system (SWHS). The SWHS was composed of a heating tank (HT), a hot water storage tank (ST) and an overhead tank (OT). The HT together with a specially designed valve act as a novel thermal water pump that gets power from hot water vapor and air pressure produced by a built-in electric heater in order to transfer heat from the HT to ST. The general operation of this pump has four stages for each cycle: heating, water circulating, vapor circulating and water supplying. The discharge water heads were varied with an increment of 0.25 m from 0.75 to 3 m. According to the experiment, it was found that the pump could operate at an average HT temperature of about 80–95 °C leading to 70–80 °C ST temperatures and 20–35 pumping cycles and consumed 17 MJ energy input during 9-h period. The overall thermal efficiency of the SWHS was 33–42% and the mean pump efficiency was about 0.005–0.011% depending upon the discharge heads.     

Analysis of defrosted water evaporation from three water trays in refrigerators

The evaporation of defrosted water from vapour compression domestic refrigerators can be a real problem in tropical countries with hot and humid ambient conditions. This poses a challenge to the refrigerator manufacturers to design a water tray with minimal additional cost but with significantly improved evaporation rates. This paper, therefore, analyses the performance of three types of water trays that were tested in dual temperature frost-free domestic refrigerators to study the evaporation rates of defrosted water. A dynamic simulation model has been developed to predict the evaporation rates from these trays. The model is based on the fundamental equations of conservation of mass and energy and includes the effects of cyclic run times of the compressor. The defrosting of the evaporators occurs only during the compressor ‘off’ cycle at a preset time and for a predetermined interval, as determined by the microprocessor. The model is successfully validated with the experimental data from the water trays.     

空调冷凝水作为水资源的回收利用

理论分析了在户式空调、中央空调末端装置的空调冷凝水的产生量，介绍了冷凝水作为冷却塔补充水、景观灌溉、水景等用途及注意事项。     

From water to energy: The virtual water content and water footprint of biofuel consumption in Spain

Energy diversification and the use of renewable energy sources are key points in the European energy strategy. Biofuels are the most popular renewable resource option for the transport sector, and the European Union has established objectives that the Member States must adopt and implement. However, biofuel production at such a scale requires a considerable amount of water resources, and this water–energy nexus is rarely taken into account. This paper shows the strong nexus between water and energy in biofuel production and estimates the virtual water (VW) content and the water footprint (WF) from the raw material production that will be needed to reach the Spanish targets for biofuel consumption by 2010. The results show how the impact of such targets on the global and local water situation could be reduced through virtual water imports and, at the same time, how these imports could increase Spain’s water and energy dependence. Hence, in order to manage water from an integral perspective of the territory, the inclusion of biofuel consumption objectives should go hand in hand with measures to reduce the demand of energy in the transport sector.     

空调冷凝水作为饮用水的回收利用

以美的MDV-JD22G/Y型挂壁式室内机为例,计算空调器冷凝水每小时产生量。从计算结果来看,空调器每日产生的水量足以提供人体每日所需水量。针对空调器的结构特点提出了冷凝水净化成饮用水的净化工艺。对净化后的冷凝水进行水质检验,各项指标符合国家标准。     

双水位可控节水洁具装置的研究

介绍一种双水位卫生间洁具水箱节水型排水阀装置。本装置为串联式提拉阀,第一级为低水位阀门,第二级为高水位阀门,两级阀门控制两个档位的排水,以适用对大小便等冲污量不同的用水量要求．尤其适合于对旧水箱的节水改进。     

发电厂凝结水泵水位控制系统

本文利用可编程序控制器 (PLC)控制变频器 (VVVF)实现对火力发电厂凝结水泵水位系统的控制 ,使凝结水泵水位保持稳定 ,可靠性有很大提高 ,同时减少了维护费用 ,节省了电能、降低了煤耗 ,节能效果显著 ,可在 12 5、2 0万kW发电机组凝结水泵上推广。