Thermal comfort assessment and energy consumption analysis of ground-source heat pump system combined with radiant heating/cooling

A new ground source heat pump system combined with radiant heating/cooling is proposed, and the principles and the advantages of the system are analyzed. A demonstration of the system is applied to a rebuilt building： Xijindu exhibition hall, which is located in Zhenjiang city in China. Numerical studies on the thermal comfort and energy consumption of the system are carded out by using TRNSYS software. The results indicate that the system with the radiant floor method or the radiant ceiling method shows good thermal comfort without mechanical ventilation in winter. However, the system with either of the methods should add mechanical ventilation to ensure good comfort in summer. At the same level of thermal comfort, it can also be found that the annual energy consumption of the radiant ceiling system is less than that of the radiant floor system.

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.

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 of U-vertical direct-expansion ground-source heat pump

The performance of a direct-expansion ground-source heat pump（DX GSHP）system is theoretically analyzed.Compared with the conventional ground-source heat pump（GSHP）,the DX GSHP has a lower condensing temperature in the cooling mode and a higher evaporating temperature in the heating mode,and the ground heat exchanger（GHE）in the DX GSHP has a low thermal resistance.Therefore,the coefficient of performance（COP）of the DX GSHP is higher than that of the GSHP.In addition,the system performance of the DX GSHP system is higher than that of the conventional GSHP system because there are no secondary solution loops and water circulating pumps in the DX GSHP system.The experimental energy performance of the DX GSHP system is also investigated based on the actual operational data.The tested DX GSHP system is installed in Xiangtan,China.The U-vertical GHE of the DX GSHP is buried in a water well.The length and the outside nominal diameter of the GHE are 42 m and 12.7 mm,respectively.The experimental results show that the maximum（COP）and the average COP of the DX GSHP system in the heating mode are 5.95 and 4.72,respectively.

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.

Performance analysis of heat pump based on a new solar air-source heat pump heating system

To further improve the utilization efficiency of solar energy and the performance of solar heat pump heating systems,a new heating mode of a solar air-source heat pump（SASHP）is proposed,and the characteristics and performance of the heat pump part of this new heating system are studied.Based on a SASHP with 10 kW,the mathematical model of this system is built,and the characteristics and performance are concluded from the simulation analysis at different environmental temperatures and output water temperatures.The results show that the performance of heat pumps can be greatly improved based on the new SASHP.When the environmental temperature is 7 ℃,the coefficient of performance（COP）of the air-source heat pump（ASHP）can be increased by 26% at most.This paper sets up a base for further study on the heating system with this new SASHP in the heating season.

Performance analysis of a novel tobacco-curing system with a solar-assisted heat pump

A novel tobacco-curing system with a solar-assisted heat pump was proposed.The proposed system has various advantages,such as reducing energy consumption and pollutant emissions and enhancing the stability of system operation.The thermal characteristics of the system under different climate conditions were analyzed,and the economic and environmental benefits of different tobacco-curing technologies were compared.Results indicated that the dehydration rate,the mass flux of exhaust air,and the heat load of the novel tobacco-curing system in different months had similar changes with the baking time,and all reached the maximum in the later stage of color fixing.Compared with the power saving rate of a heat pump tobacco-curing system,that of the novel system reached 25.9%-35.1%.The dry leaf curing cost of the novel system was only 0.86-1.06 yuan/kg,which can reduce the cost by more than 60%compared with traditional coal-burning tobacco-curing systems in China.Compared with other parts of the tobacco leaf,the top leaf had the lowest dry leaf curing cost due to its highest mass of dry leaf.The payback period and the annual CO_(2) emission reduction of the novel system were 3.0-3.7 a and 15586 kg,respectively.

Efficiency of Combined Solar Thermal Heat Pump Systems

In this project, different combinations of solar energy and heat pump systems for preparation of DHW （domestic hot water） and space heating of buildings are analyzed through dynamic system simulations in TRNSYS （Transient System Simulation Program）. In such systems, solar thermal energy can be used, on one hand, directly to charge the buffer storage and, on the other hand, as heat source for the evaporator oftbe HP （heat pump）. In this work systems, in which solar heat is only used directly （parallel operation of solar and HP）, systems using the collectors also as a heat source for the HP are analyzed and compared to conventional air HP systems. With a combined parallel solar thermal HP system, the system performance compared to a conventional HP system can be significantly increased. Unglazed selectively coated collectors as source for the HP have the advantage that the collector can be used as an air heat exchanger. If solar radiation is available and the collector is used as source for the HP, higher temperatures at the evaporator of the HP can be achieved than with a conventional air HP system.

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。

多源分布式换能系统构建理论方法研究与应用

“双碳”背景下分布式换能系统以其在低碳环保方面的显著优势逐渐在集中供热领域得到应用。本文针对分布式换能系统中热泵、太阳能集热器、板式换热器和燃料电池等关键单元提出了单元能耗评价方法,并通过EES软件对各单元进行了热力学建模以定量评价不同单元在不同工况下的经济性,进而提出分布式换能系统的构建方法以获得流程经济性最优化。以此为依据搭建了最优化流程,并以北京地区某小区为例分析了该系统的供暖季性能,最后进行了经济性和碳减排分析。结果表明:室外温度在-10~5℃范围内变化时,该新型分布式换能系统的COP为2.69~4.43,太阳能集热器效率为45.19%~61.87%,燃料电池日发电量为8047.4~32228.0 kW·h;与常规热力站相比,该新型分布式换能系统的运行成本节省率为32.66%~53.92%,碳减排率为69.07%~73.29%。

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Dymola的太阳能-热泵双水箱复合供暖系统参数优化设计

为降低西北地区居民使用太阳能复合供暖系统的经济成本和碳排放量,并提高太阳能利用率,设计一种太阳能-热泵双水箱复合供暖系统,并优化其重要参数。利用Dymola平台,搭建太阳能-热泵双水箱复合供暖系统模型,目标函数是系统全生命周期成本,选取太阳能集热器面积、集热器安装倾角、水箱容量和热泵功率作为优化变量,采用遗传算法同步优化系统所选变量,并对系统的环保性进行分析。以宁夏地区为案例进行优化计算,结果表明,所创建的数学模型准确性较好,比较模拟数据与实验数据,二者平均误差均在±8%以内。在系统15年寿命周期内,优化后系统性能系数提高10.3%,水箱平均温度提高至54.71℃,系统生命周期成本减少5.3%,节能率为24.4%,节能效果显著。系统的SO_(2)、CO_(2)、NOx及烟尘的减排量分别为0.82、26.6、0.41、7.48t,该系统可以显著降低环境影响,与传统燃煤锅炉相比减排效果显著。

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。

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。

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。