太阳能热泵联合系统的枸杞干燥特性与能耗分析

为降低碳排放,利用太阳能集热器与空气源热泵联合干燥代替传统的燃煤热风炉干燥。通过对比太阳能热泵联合干燥和热泵单独干燥试验,研究太阳能热泵系统除湿特性。同时,进行太阳能空气集热器辅助空气源热泵的枸杞干燥试验,验证其可行性。在相同干燥温度设定下,太阳能热泵联合干燥相比热泵单独干燥节电了28.8%,高干燥负荷试验组较中等干燥负荷试验组相比节电15%。与传统热风炉烘干房干燥相比,每吨枸杞干燥节约成本448元,同时节约标准煤121.14 kg,可减少CO2排放量317.39 kg。     

太阳能与热泵联合干燥茶叶的应用研究

为开发茶叶干燥新方法,利用太阳能集热与热泵联合干燥代替传统的干燥方式,采用相变蓄热和辅助热源保证干燥系统能够全天候工作。使用空气源热泵技术作为太阳能集热系统辅助热源和策略控制,达到节能高效目的。经干燥茶叶试验研究表明,采用相变蓄热太阳能与空气源热泵联合干燥,能够解决干燥系统能量供应的稳定性和经济性问题,整个联合干燥系统与燃煤烘箱干燥相比,节能36.7%~41.1%,节能减排效果显著。从茶叶的干燥特性试验中得出在50~60℃间,均可在8 h内达到所要求的含水率,干燥时间随干燥风温的升高而缩短,干燥后的茶叶质量等级相比同等条件下的传统干燥方式有所提高。     

太阳能联合空气源热泵系统温室供热实验研究

在西安地区一座日光温室中采用太阳能联合空气源热泵供热系统进行对比实验研究,比较太阳能联合空气源热泵系统改善温室内的温度、湿度及土壤温度等环境因素,分析评价太阳能联合空气源热泵系统在日光温室冬季应用的效果。实验结果表明:太阳能联合空气源热泵供热系统不仅可明显提高温室内的空气温度和土壤温度,还可有效降低温室内的湿度;在实验天气条件下,热泵单独供热时,系统的COP为2.2~3.5;太阳能联合空气源热泵供热时,系统的COP为2.9~6.0;相比于阴天工况,晴天条件下,太阳能蓄热供热时间较长,热泵补充供热时间缩短,系统COP较高。     

基于太阳能补偿的空气源热泵系统性能分析

分别设计和搭建了传统空气源热泵系统和基于太阳能补偿的空气源热泵系统为住宅供暖和提供全年生活热水,通过计算对2种系统的主要部件进行选型,并使用POLYSUN软件对这2种系统方案进行建模,对其全年运行工况进行模拟和对比分析。结果显示,基于太阳能补偿的空气源热泵系统比传统空气源热泵系统每年可节约电能1138.3 kWh,节能率达49.4%,年运行费用可节省557.8元,年减排CO_2 610.6kg,经济效益和环境效益显著。     

PCM空气式太阳能干燥在茶叶加工中的应用

介绍了云南普洱市的某茶业公司PCM空气式太阳能一热泵联合干燥房建设及应用实例。普洱茶传统加工工艺采用燃煤蒸汽锅炉进行茶饼烘干处理,现进行技术改造,采用节能环保的PCM空气式太阳能热泵干燥系统代替现有的燃煤锅炉干燥系统。通过PCM空气式太阳能集热系统,将太阳能转换热能。以空气为换热介质与空气式太阳能集热器进行换热,通过循环风机直接将热风通入到烘房内提供物料干燥热量需求;当太阳能不足时,启动空气源热泵系统。对该工程的设计方案并及干燥系统工作原理进行了详细介绍,从干燥系统运行过程中采集数据进行分析计算,计算结果表明本干燥系统节能效果明显。这些数据对目前高效利用太阳能进行商业干燥设计参数的选取,以及太阳能干燥系统的优化设计具有重要借鉴意义。     

广东地区太阳能-空气源热泵复合系统供暖供生活热水实验研究

构建了一种太阳能-空气源热泵复合供热系统,在广东地区冬季的晴天和全阴天进行供暖供生活热水实验测试。针对办公建筑供暖供生活热水需求,定时间段供生活热水同时进行供暖实验。实验结果表明:晴天热泵相较于全阴天工况节电1.16 kW·h,供热效果优于全阴天工况,太阳能-空气源热泵复合供热性能相较于单独的空气源热泵更有显著优势;太阳能-空气源热泵复合系统供暖供生活热水期间,复合系统COP_(sys)平均值为4.71、波动范围在4.20～5.38,空气源热泵系统COP_(hp)平均值为4.60、波动范围在4.08～5.10。     

太阳能-热泵木材干燥系统

一干燥系统原理太阳能 热泵木材干燥系统主要由四部分组成 ,即太阳能加热系统、干燥室、热泵除湿机（干燥机）和微机监测与控制系统。木材干燥系统的供热与湿空气的排湿由太阳能加热系统和热泵除湿机二者配合起来完成。二者既可单独使用 ,也可联合使用。如果天气晴好 ,气温高 ,则可单独使用太阳能加热系统 ;天气不好或夜间 ,即可由干燥机来承担木材干燥的供热与除湿任务。太阳集热器为拼装式平板型空气集热器 ,它采取阵列形式布置 ,可以根据需要拼装成任何采光面积 ,安装维修都很方便 ;干燥室为金属型结构 ,外砌砖墙 ,内贴铝板 ,中间衬以保…     

太阳能联合热泵型煤干燥系统设计

为了减少污染降低成本,设计了一套太阳能空气集热器、空气源热泵和热泵蒸汽机组联合干燥系统。通过实验测试和热量衡算后,拟采用400 m~2的空气集热器、8台空气源热泵和3台蒸汽热泵机组即可满足型煤干燥需求。预计改造费用约236万元,投资回收期2.7年;成本由35元/t降低为21.6元/t;年节约标煤2 660 t以上,减排CO_2约6 916 t,减排SO_2约63.84 t,减排NO_x约18.62 t,改造后具有较好的经济效益和环境效益。     

太阳能辅助的双源耦合热泵系统制热特性研究

传统空气源热泵在较低环境温度下存在制热量不足和制热效率偏低问题,该文提出一种太阳能辅助的双源双压缩耦合热泵系统,通过集热器将太阳能转化为低温热水以构建太阳能水源热泵单元,利用2台压缩机和1台冷凝器实现太阳能水源热泵单元和空气源热泵单元并联耦合工作。太阳能水源热泵单元和空气源热泵单元既能各自独立运行又能同时运行以满足用户全天候热负荷需求。基于DeST软件评估一个供热期(120 d)郑州某建筑逐时热负荷特性。在建立热力学数学模型基础上编写程序进行新系统循环特性计算和能耗分析,结果表明:双源耦合热泵系统COP_h较传统空气源热泵明显升高;前者日节能率介于1.01%～14.75%之间,在整个供热期总能耗较后者减少8.72%。双源(空气源蒸发器和水源蒸发器)双压缩机并联流程耦合热泵比双源单压缩机串联流程耦合热泵更具有节能优势。     

日间供暖太阳能热泵系统负荷分析及面积优化

以青岛市某公司办公楼太阳能热泵系统为研究对象,通过TRNBuild建立建筑模型,仿真分析同一建筑全天供暖与日间供暖热负荷分布特点,针对建筑日间供暖需求建立太阳能-空气源热泵仿真供热系统,利用TRNSYS软件进行供热季仿真模拟,计算日间供暖集热器最佳设计面积。仿真结果表明：相较于全天供暖,建筑日间供暖热负荷波动更为剧烈,最大峰值约为全天供暖的2倍,针对日间供暖设计的太阳能热泵系统在集热器面积为417 m²时运行经济性最佳,系统COP可达4.1,对应太阳能贡献率为24.7%,供暖季相较于传统空气源热泵可节约电能9 091 kW·h。     

中低温热源干燥系统的设计及试验

为解决工农业干燥过程中存在的干燥效率低、能耗高等问题,同时充分利用生产过程中产生的中低品位热能,设计了一种可控温湿度的中低温热源干燥系统,干燥系统由加热系统、排湿换气系统、温湿度控制系统和干燥室组成。介绍了其干燥工艺,分析了其运行性能和能耗情况,通过试验数据分析发现该干燥系统气流温度和速度分布均匀、能耗低,系统在整个干燥过程中的干燥速率为0.122 kg/(kg∙h),整个过程的能耗因子为391.2 kJ/kg。系统适用于以地热能和工业余热等中低温热能为热源的工农业干燥过程。     

Review of solar assisted heat pump drying systems for agricultural and marine products

Combining solar energy and heat pump technology is a very attractive concept. It is able to eliminate some difficulties and disadvantages of using solar dryer systems or solely using heat pump drying separately. Solar assisted heat pump drying systems have been studied and applied since the last decades in order to increase the quality of products where low temperature and well-controlled drying conditions are needed. This paper reviewed studies on the advances in solar heat pump drying systems. Results and observation from the studies of solar assisted heat pump dryer systems indicated that for heat sensitive materials; improved quality control, reduced energy consumption, high coefficient of performance and high thermal efficiency of the dryer were achieved. The way forward and future directions in R&D in this field are further research regarding theoretical and experimental analysis as well as for the replacement of conventional solar dryer or heat pump dryer with solar assisted heat pump drying systems and solar assisted chemical and ground source heat pump dryers which should present energy efficient applications of the technologies.     

Performance analysis of a heat pump assisted drying system

The paper describes a simulation model developed to predict the performance of drying systems assisted by vapour-compression heat pumps. The heat is used to preheat the air stream before it enters the drying chamber. Energy consumption is thus reduced, as the heat pump is capable of delivering more energy as heat than it in fact consumes as input work. Ambient air provides the heat source. A computer program, based on simplified modelling of components (compressor, heat exchangers and drying chamber) has been developed. Results have been produced for a typical application, revealing that a considerable reduction in energy consumption can be obtained with the use of a heat pump. The effect of air flow rate on system performance is also studied.     

Experimental results of a solar assisted heat pump rice drying system

In the last rice harvest season, experimental results have been obtained on the efficiency and drying quality of a solar assisted heat pump drying prototype system. The system has been operated as a solar and heat pump system and drying curves for the different options have been obtained. The advantage of the low temperature and better control in the drier shows that the heat pump assisted solar drying system is an excellent alternative to traditional drying systems.     

A solar assisted heat pump drying system for grain in-store drying

For grain in-store drying, a solar assisted drying process has been developed, which consists of a set including a solar-assisted heat pump, a ventilation system, a grain stirrer, etc. In this way, low power consumption, short cycle time and water content uniformity can be achieved in comparison with the conventional method. A solar-assisted heat pump drying system has been designed and manufactured for a practical granary, and the energy consumption performance of the unit is analyzed. The analysis result shows that the solar fraction of the unit is higher than 20%, the coefficient of performance about system (COPS) is 5.19, and the specific moisture extraction rate (SMER) can reach 3.05 kg/kWh.     

A solar assisted heat pump drying system for grain in-store drying

For grain in-store drying, a solar assisted drying process has been developed, which consists of a set including a solar-assisted heat pump, a ventilation system, a grain stirrer, etc. In this way, low power consumption, short cycle time and water content uniformity can be achieved in comparison with the conventional method. A solar-assisted heat pump drying system has been designed and manufactured for a practical granary, and the energy consumption performance of the unit is analyzed. The analysis result shows that the solar fraction of the unit is higher than 20%, the coefficient of performance about system (COP_S) is 5.19, and the specific moisture extraction rate (SMER) can reach 3.05 kg/kWh.     

热泵干燥系统的空气旁通率的遗传算法优化

首先介绍了适用于干燥领域的热泵干燥系统,空气的旁通率影响着干燥系统的有效性与经济性。综合考虑系统除湿效果和热泵机组运转能耗,推导出了系统除湿时的优化模型。以某一具体问题为例,采用遗传算法对热泵干燥系统除湿比能耗进行了优化,得出了空气最佳旁通率及其运行情况,对热泵干燥系统的设计、运行具有一定的指导作用。     

太阳能与空气源热泵复合式供暖系统在西安地区的应用特性分析及评价

以西安地区的某个房间为研究对象,采用TRNSYS软件针对该房间分别应用太阳能集热系统、空气源热泵系统及太阳能与空气源热泵复合式供暖系统进行供暖时的情况进行了分析.首先,建立了太阳能与空气源热泵复合式供暖系统的仿真模型,并对其正确性进行了实验验证;其次,对比分析了在3种运行模式下各个系统的运行特性;最后,以系统能耗及能效...     

复合热源太阳能热泵供热系统及其性能模拟

提出了一种复合热源太阳能热泵供热系统,通过阀门切换,可根据不同的天气状况改变运行模式,以空气和太阳辐射作为热源制取供暖用水。针对所设计的10kW供热系统,建立了系统的数学模型,对热泵串联集热器(SC+HP)及集热器串联热泵(H+SC)两种运行模式下的循环性能进行了计算机模拟分析,并计算了系统的全年运行状况。从模拟结果可以看出,在模拟进水温度区间内,HP+SC模式下热泵COP较高,最高比SC+HP模式高2.58%;而SC+HP模式集热器热性能较好,总热效率更高,最高比HP+SC模式高2.62%。     

Exergetic performance evaluation of heat pump systems having various heat sources

In this study heat pump systems having different heat sources were investigated experimentally. Solar‐assisted heat pump (SAHP), ground source heat pump (GSHP) and air source heat pump (ASHP) systems for domestic heating were tested. Additionally, their combination systems, such as solar‐assisted‐ground source heat pump (SAGSHP), solar‐assisted‐air source heat pump (SAASHP) and ground–air source heat pump (GSASHP) were tested. All the heat pump systems were designed and constructed in a test room with 60 m² floor area in Firat University, Elazig (38.41°N, 39.14°E), Turkey. In evaluating the efficiency of heat pump systems, the most commonly used measure is the energy or the first law efficiency, which is modified to a coefficient of performance for heat pump systems. However, for indicating the possibilities for thermodynamic improvement, inadequate energy analysis and exergy analysis are needed. This study presents an exergetic evaluation of SAHP, GSHP and ASHP and their combination systems. The exergy losses in each of the components of the heat pump systems are determined for average values of experimentally measured parameters. Exergy efficiency in each of the components of the heat pump systems is also determined to assess their performances. The coefficient of performance (COP) of the SAHP, GSHP and ASHP were obtained as 2.95, 2.44 and 2.33, whereas the exergy losses of the refrigerant subsystems were found to be 1.342, 1.705 and 1.942 kW, respectively. The COP of SAGSHP, SAASHP and GSASHP as multiple source heat pump systems were also determined to be 3.36, 2.90 and 2.14, whereas the exergy losses of the refrigerant subsystems were approximately 2.13, 2.996 and 3.113 kW, respectively. In addition, multiple source heat pump systems were compared with single source heat pump systems on the basis of the COP. Exergetic performance coefficient (EPC) is introduced and is applied to the heat pump systems having various heat sources. The results imply that the functional forms of the EPC and first law efficiency are different. Results show that Ex_loss,total becomes a minimum value when EPC has a maximum value. Copyright © 2008 John Wiley & Sons, Ltd.