Modeling and Optimization of Solar Collector Design for the Improvement of Solar-Air Source Heat Pump Building Heating System

To enhance system stability,solar collectors have been integrated with air-source heat pumps.This integration facilitates the concurrent utilization of solar and air as energy sources for the system,leading to an improvement in the system’s heat generation coefficient,overall efficiency,and stability.In this study,we focus on a residential building located in Lhasa as the target for heating purposes.Initially,we simulate and analyze a solar-air source heat pump combined heating system.Subsequently,while ensuring the system meets user requirements,we examine the influence of solar collector installation angles and collector area on the performance of the solar-air source heat pump dual heating system.Through this analysis,we determine the optimal installation angle and collector area to optimize system performance.

Research on Operation Optimization of Heating System Based on Electric Storage Coupled Solar Energy and Air Source Heat Pump

For heating systems based on electricity storage coupled with solar energy and an air source heat pump(ECSA),choosing the appropriate combination of heat sources according to local conditions is the key to improving economic efficiency.In this paper,four cities in three climatic regions in China were selected,namely Nanjing in the hot summer and cold winter region,Tianjin in the cold region,Shenyang and Harbin in the severe cold winter region.The levelized cost of heat(LCOH)was used as the economic evaluation index,and the energy consumption and emissions of different pollutants were analyzed.TRNSYS software was used to simulate and analyze the system performance.The Hooke-Jeeves optimization algorithm and GenOpt software were used to optimize the system parameters.The results showed that ECSA systemhad an excellent operation effect in cold region and hot summer and cold winter region.Compared with ECS system,the systemenergy consumption,and the emission of different pollutants of ECSA system can be reduced by a maximum of 1.37 times.In cold region,the initial investment in an air source heat pump is higher due to the lower ambient temperature,resulting in an increase in the LOCH value of ECSA system.After the LOCH value of ECSA system in each region was optimized,the heating cost of the system was reduced,but also resulted in an increase in energy consumption and the emission of different pollutant gases.

Simulation of embedded heat exchangers of solar aided ground source heat pump system

Aimed at unbalance of soil temperature field of ground source heat pump system, solar aided energy storage system was established. In solar assisted ground-source heat pump (SAGSHP) system with soil storage, solar energy collected in three seasons was stored in the soil by vertical U type soil exchangers. The heat abstracted by the ground-source heat pump and collected by the solar collector was employed to heating. Some of the soil heat exchangers were used to store solar energy in the soil so as to be used in next winter after this heating period; and the others were used to extract cooling energy directly in the soil by circulation pump for air conditioning in summer. After that solar energy began to be stored in the soil and ended before heating period. Three dimensional dynamic numerical simulations were built for soil and soil heat exchanger through finite element method. Simulation was done in different strata month by month. Variation and restoration of soil temperature were studied. Economy and reliability of long term SAGSHP system were revealed. It can be seen that soil temperature is about 3 ℃ higher than the original one after one year's running. It is beneficial for the system to operate for long period.

Experimental Investigation on System with Combination of Ground-Source Heat Pump and Solar Collector

This paper presents the heating performance and energy distribution of a system with the combination of ground-source heat pump and solar collector or a solar-assisted ground-source heat pump system (SAGSHPS) by calculation and experiment.The results show that the average absolute error is less than 0.6 ℃ and the relative error is less than 5% under the pulse load when the analytical solution to the 2-D solid cylindrical source model is used for the SAGSHPS.The coefficient of performance (COP) of the SAGSHPS is 2.95-4.70.The average fluid temperature in the borehole heat exchanger can increase by 3 ℃ with the assistance of solar collector,which will improve the COP of the heat pump by approximately 10% from the experimental data.The energy contributions to the total heating load of soil,electricity and solar are 56.30%,36.87% and 6.83%,respectively.

Performance analysis on solar-water compound source heat pump for radiant floor heating system

A solar-water compound source heat pump for radiant floor heating (SWHP-RFH) experimental system was introduced and analyzed. The SWHP-RFH system mainly consists of 11.44 m2 vacuum tube solar collector,1 000 L water tank assisted 3 kW electrical heater,a water source heat pump,the radiant floor heating system with cross-linked polyethylene (PE-X) of diameter 20 mm,temperature controller and solar testing system. The SWHP-RFH system was tested from December to February during the heating season in Beijing,China under different operation situations. The test parameters include the outdoor air temperature,solar radiation intensity,indoor air temperature,radiation floor average surface temperature,average surface temperature of the building envelope,the inlet and outlet temperatures of solar collector,the temperature of water tank,the heat medium temperatures of heat pump condenser side and evaporator side,and the power consumption includes the water source heat pump system,the solar source heat pump system,the auxiliary heater and the radiant floor heating systems etc. The experimental results were used to calculate the collector efficiency,heat pump dynamic coefficient of performance (COP),total energy consumption and seasonal heating performance during the heating season. The results indicate that the performance of the compound source heat pump system is better than that of the air source heat pump system. Furthermore,some methods are suggested to improve the thermal performance of each component and the whole SWHP-RFH system.

The Characteristics of the Evaporator/Evaporator for Direct Expansion Solar Assisted Heat Pump System

Direct expansion solar assisted heat pump (DX-SAHP) technology is developed by combining solar energy heat utilization with heat pump energy saving technology. The experimental researches of the DX-SAHP hot water system are conducted in this paper, and overall performance of DX-SAHP is analyzed with three different structures of collectors/evaporators, namely a bare-plate collector, a glass-plate collector and double collectors/evaporators (a bare-plate collector and a glass-plate collector). The influence factors and overall performance are studied, which show that the overall performance of the system is mainly influenced by solar irradiation intensity and the collector area. Comparing with glass-plate collector in similar conditions, bare-plate collector system COP is higher. While increasing collector area is conducive to improve the system COP, but will reduce the collector efficiency and increase the workload of the compressor by comparing the bare-plate collector with double-plate collectors.

太阳能-空气源热泵牧草干燥系统制热性能研究

以太阳能-空气源热泵牧草干燥系统为研究对象,通过系统不同工作模式的温升、恒温制热试验及带载试验,分析了温升速率、单位温升能耗、COP及除湿效率。研究结果表明:联合制热模式与太阳能单独制热相比,单位温升耗电量降低了86.2%,温升速率提高了99~112倍。联合制热模式与热泵单独制热试验相比,在温升过程中温升速率降低了7.7%~17.6%,单位温升耗电量降低8.0%;在恒温制热过程中,前者COP比后者提高了6.5%~11.1%,耗电量降低了5.8%~10.7%;在升温制热过程中前者COP比后者提高了6.0%~10.4%,耗电量降低了6.6%~11.1%。联合干燥模式比热泵单独干燥模式的SMER值高19.8%~36.2%。

基于ANFIS的太阳能-空气源热泵供暖系统温度控制研究

针对太阳能-空气源热泵供暖系统运行环境复杂多变,模糊控制器的设计高度依赖人工经验的问题,提出一种基于自适应神经模糊推理系统(ANFIS)改进的模糊控制方法。该方法利用ANFIS在复杂系统建模中的优势,结合供暖系统温度响应特性和实际运行数据,建立联合供暖系统变工况ANFIS模型,生成与系统性能适配的模糊规则库并传递给模糊控制器执行。Matlab/Simulink仿真对比试验表明,与单一的模糊控制相比,该方法的控制精度提高了17.65%,调节时间缩短了36.4%,具有更高的控制精度和响应速度。

超低温空气源热泵与太阳能供热系统在寒冷地区的优化应用

为了加强对环境的保护,推动可持续发展社会的建设,超低温空气源热泵联合太阳能供热系统被研发出来。该联合系统的应用极大地缓解了当前能源紧张的问题,同时对降低环境污染、提高能源利用率、降低供暖成本也有着积极的作用。基于此,围绕超低温空气热源泵与太阳能供热系统展开论述,对当前超低温空气源热泵与太阳能联合供热系统结构进行分析,剖析其中所存在的问题,同时针对问题提出超低温空气源热泵与太阳能供热系统的优化方案,将其应用于北方寒冷地区的一建筑当中,并对应用效果进行分析。

太阳能光热光电技术在高校宿舍的对比研究

针对夏热冬冷地区某高校宿舍用能特征,基于太阳能的两种利用方式分别设计了太阳能光热供能系统和太阳能光电供能系统。利用TRNSYS仿真软件模拟两种供能系统的运行特性,对比了两种系统的组件性能、经济性及减排量。结果表明:除假期时间外,太阳能集热单元的集热效率保持在40%左右,年太阳能保证率可达58%;并网光伏发电单元全年发电量为311 394 kW·h,发电量自用率达到70.5%。太阳能光电供能系统的年能耗费用较光热供能系统节省11万元,费用年值减少4.9万元,年碳排放量降低166 t。对光伏安装面积进行优化后可知,光伏安装面积每增加52 m^(2),光伏供能系统费用年值减少2111元。研究结果可为高校宿舍建筑选择适宜的太阳能利用形式提供参考和依据。

基于正交试验法的太阳能复合热水系统优化

为降低生活热水能耗,实现空气源热泵辅助太阳能供热水系统的高效节能运行,选取济南市某高校学生宿舍空气源热泵辅助太阳能供热水系统作为研究对象,利用瞬时系统模拟软件搭建了系统仿真模型,并采用无交互作用的正交试验法,分别以全年系统性能系数和太阳能保证率为优化目标,优化了太阳能集热器面积、集热器倾角、热泵制热功率及水箱容积,并分析其结果的经济性和节能性。结果表明:当以系统性能系数为优化目标时,最优组合中集热器面积为390 m^(2)、集热器倾角为42°、热泵制热功率为50 kW、水箱容积为23.94 m3,而动态费用年值为7.38万元,较天然气系统年节省标煤为17.12 tce;当以太阳能保证率为优化目标时,最优组合中集热器面积为342 m^(2)、集热器倾角为44°、热泵制热功率为35.5 kW、水箱容积为20.58 m3,而动态费用年值为6.56万元,较天然气系统年节省标煤为16.63 tce。

光伏光热-双源热泵系统地区适用性研究

利用TRNSYS软件建立了光伏光热-双源热泵(PV/T-DSHP)系统仿真模型,选取拉萨和上海对PV/T-DSHP系统的运行特性进行了模拟分析,对不同室外气象条件(环境温度、太阳辐照度)下单一光伏-空气源热泵(PV-ASHP)系统和光伏光热-水源热泵(PV/T-WSHP)系统的性能系数进行了对比分析。结果表明:PV/T-DSHP系统在拉萨和上海的供暖季平均系统性能系数(COP s)分别为4.23和3.34;在太阳能资源一般区和丰富区,PV/T-WSHP系统较PV-ASHP系统在根据环境温度和太阳辐照度划定的最佳COP*s运行区域内运行更具性能优势。

太阳能-空气源热泵热水系统新型组合优化设计

太阳能-空气源热泵热水系统(solar-air source heat pump hot water system, SAHWS)常用于宿舍楼宇供暖,通过对系统参数的优化设计可显著提高系统能效性能与环境友好性。为得到一种综合考虑SAHWS经济、能源、环保与节能的优化方法,提出了一种新型组合优化设计策略,并利用TRNSYS软件搭建系统仿真模型,以西安、西宁、拉萨这3座不同太阳能资源等级城市为例,对SAHWS运行工况对比分析。结果表明:与常用生命周期成本设计相比,所提出的组合优化设计不仅降低了系统成本,还有着较低的系统能耗;组合优化设计的热泵能耗与工作小时数最短,且有最低的热损,在投资成本、系统季节性能因子、太阳能保证率以及碳粉尘、二氧化碳排放量均有较好表现。

基于TRNSYS的太阳能-热水源热泵复合供暖系统运行优化

针对太阳能供暖技术与热泵供暖技术的不足,提出了一种太阳能-热水源热泵复合供暖系统,并以西藏日喀则地区某项目为研究对象,利用TRNSYS仿真模拟软件建立太阳能-热水源热泵复合供暖系统模型,模拟分析该供暖系统的运行特性,并对系统的经济性进行了分析,然后利用Hooke-Jeeves优化算法对供暖系统关键参数进行优化。结果表明:西藏地区太阳能-热水源热泵复合供暖系统能够高效稳定运行,实现了对太阳能由高温到低温的梯级利用,供暖季系统季节能效比可达4.43;相比于电锅炉供暖,复合供暖系统具有更高的经济性,静态回收期为5.3年;优化后系统能耗减少,供暖季系统季节能效比提高了7.9%。

基于PV/T的双源热泵热水系统的实验研究

为提高热泵热水循环的效率,构建基于光伏/光热一体化(PV/T)的双源热泵热水系统,选取全年中4个典型日,测试系统的可靠性、热泵运行性能以及PV/T运行特性。结果表明:系统的电源和热源可稳定使用;4个典型工况中,环境温度为27.3℃、太阳辐照度为975.6 W/m^(2)时热泵运行性能最优,制热系数(COPh)达到6.2,PV/T性能最优,平均光电转换效率相对于传统光伏组件高6.6%,总发电量比传统光伏组件高0.11 kWh。

基于PSO-MSVR的太阳能耦合土壤源热泵系统优化配置

为了优化太阳能耦合土壤源热泵系统(SGSHPS)的配置,以沈阳地区办公建筑为例,基于TRNSYS平台建立了不同运行模式的SGSHPS模型,对比分析不同模式下系统运行30 a后土壤温度不平衡率和系统总能耗;以并联过渡季蓄热模式为对象,对不同的太阳能集热系统和地埋管换热器组合方式进行模拟;在保证系统稳定的前提下,以动态费用年值最低为目标,优化太阳能集热器面积和地埋管换热器钻孔数的配置方式;引入粒子群优化-多输出支持向量机回归(PSO-MSVR)算法,使用PSO算法生成MSVR模型参数并寻找最优值。结果表明:与采用传统热平衡法确定的配置方式相比,优化后运行30 a的系统能耗降低379522 kW,节能11.2%,费用年值降低61863元,土壤温度仅上升0.73 K;对于不同的太阳能集热器和地埋管换热器造价,优化后费用年值相较优化前仍有不同程度的节省,且土壤温度均未有较大偏移。

粮食平房仓太阳能光伏-地源热泵供冷系统仿真研究与试验

为解决粮食平房仓通风能耗大、储粮成本高的问题,该研究提出太阳能-地源热泵供冷系统,研究太阳能光伏-地源热泵供冷系统在粮食平房仓建筑中的可行性以及节能效果,以实现“零能耗”和“零排放”绿色储粮。基于粮食平房仓实际尺寸,建立了空气源热泵与太阳能光伏-地源热泵供冷系统仿真模型,并通过与仓房实测数据的对比进行了模型验证,从运行性能、光电适配性、经济性、节能以及环保效益等方面对供冷系统进行了分析。结果表明:系统运行1 a后性能系数(coefficient of performance,COP)最大值为4.76,最小值3.3;运行10 a后COP最大值为3.96,最小值3.07;系统年实际发电量与库区用电量之比为192%~270%;投资回收期为7.8 a;与传统空气源热泵系统相比,太阳能-地源热泵供冷系统节能率达59%,研究结果可为粮食平房仓供冷系统优化提供理论依据和设计参考。

温室太阳能跨季节蓄热-土壤源热泵耦合供暖运行特性

针对温室采用土壤源热泵供暖存在土壤热失衡明显、土壤温度和供暖能效逐年降低的问题,该研究在112 m^(2)玻璃温室建设了耦合太阳能跨季节蓄热的土壤源热泵供暖系统,通过两个供暖周期试验,对热泵机组的运行、土壤热失衡、太阳能跨季节蓄热以及太阳能直供-土壤源热泵耦合供暖的运行特性进行深入分析。结果表明,在土壤源热泵供暖结束后,工作井温度下降2.40~2.97℃、监测井土壤温度下降0.60~1.00℃,土壤热失衡问题突出;太阳能跨季节蓄热使得监测井土壤温度较初始地温上升约0.2℃,有效解决了土壤热失衡问题;耦合供暖时太阳能直供可承担11%的热负荷,使得温室供暖能效系数从上一年度的2.79提升至3.19,提高了14.3%,节能效果明显。该研究揭示了供暖系统全年度和典型工况下的运行特性,实证了耦合太阳能解决土壤源热泵热失衡问题的可行性和高效性,并给出了系统高效运行主要操作参数的推荐值,为温室供暖相关研究与工程应用提供案例参考和数据支撑。

应用埋式毛细管网换热器的海水源热泵系统适用性研究

海水源热泵系统面临着生物附着、管道腐蚀、严寒天气换热器结冰等问题,影响其性能系数。将材质为PP-R的毛细管网换热器埋置于海床砂土中的海水源热泵系统能够有效避免以上问题。基于能耗模拟数据,对比了海水源热泵系统、空气源热泵系统和冷水机组+燃气锅炉系统的经济性和环保性。结果显示,应用埋式毛细管网换热器的海水源热泵系统的经济效益和环保效益均为最优。系统运行20年,海水源热泵系统的全寿命周期成本为459.5万元,最小年费用为46.8万元,建筑生命周期内其单位面积的碳排放量比空气源热泵系统低10%,比冷水机组+燃气锅炉系统低21%。本研究使消费者对该热泵系统有了更深的了解,为推广此应用提供数据支撑。

高校宿舍太阳能-空气源热泵复合热水系统设计与应用探讨

在当前积极倡导节能减排的政策要求下,可再生能源利用逐渐普及。以西安建筑科技大学学生宿舍太阳能-空气源热泵复合热水系统为例,阐述了复合热水系统的构成、工作原理,对太阳能集热系统、空气源热泵换热系统、热水供水系统等进行了设计计算,给出了集热器、热泵机组、集热水箱、供热水箱等主要设备的选型结果,提出了系统运行控制方案,并结合实际运行工况下的热性能数据,计算得到系统在不同季节的太阳能保证率、热泵能效比COP值,表明系统具有极大的节能性。