Development and Experimental Study of Air Source Heat Pump Water Heater

The principle and development prospect of air source heat pump water heat were introduced,as well as the designation of condenser (storage water tank),experimental study on installations was also carried out.The results showed that air source heat pump water heater was superior to conventional system.Under the operation of cooling and heating,heat pump comprehensive utilization equipment could improve heating performance,reduce energy consumption,and recycle condensing heat to provide hot water.

Study on corrosion behavior of heat exchanger in water source heat pump

Water source heat pump is a new kind of energy saving process.One of the most common problems for water source heat pump system is the corrosion of the copper in heat exchanger.The quality of water is the key factor.The river water collected in six different places of the Yangtze River and Jialing River in Chongqing were analyzed.Various parameters(pH,coexisted ions,and hardness value)were investigated.It showed that the Yangtze River and Jialing River water was suitable for developing water source heat pump technology.Further more,aimed at the temperature and pH of the raw water's variation range in a year,the corrosion behavior of copper material was studied by controlling the water environmental condition.Corrosion rate of copper is accelerated at high temperature and lower pH value.

Development of Instantaneous Hot Water Dispenser Based on Water Source Heat Pump

Natural energy use is important to reduce the energy consumption of buildings. However, further reducing energy consumption with traditional systems is difficult. Therefore, we proposed a MMHP （multi-source and multi-use heat pump） to achieve higher efficiency than traditional systems. The MMHP system connects multiple heat sources such as solar heat, the ground, and air and multiple heat uses such as cooling, heating, and a hot water dispenser with a water loop. Each type of heat use side can utilize heat efficiently. However, there is a distinct lack of highly efficient hot water dispensers available. Therefore, we developed the IHWD WS （instantaneous hot water dispenser based on a water source） heat pump. In this study, we developed a prototype of the IHWD WS heat pump. The coefficient of performance of the IHWD WS heat pump was 5.2-8.5 throughout a year. When it is improved, COP （coefficient of performance） is expected to be 9.3-9.9.

Performance and Optimization of Air Source Heat Pump Water Heater with Cyclic Heating

A new type of microchannel condenser applied in the air source heat pump water heater(ASHPWH)with cyclic heating was proposed in this study.The operating performance of the ASHPWH was frst tested.Then,the structure of the microchannel condenser was optimized with the implement of vortex generators.Finally,a numerical model of the ASHPWH was established and the optimized microchannel condenser was studied.The experimental results showed that the average coefficient of performance(COP)of the 1HP(735 W)ASHPWH reached 3.48.In addition,the optimized microchannel condenser could be matched with a 3 HP(2430W)ASHPWH with an average heating capacity of 10.30 kW,and achieving an average COP of 4.24,14.6%higher than the limit value in the national standard.

地铁车站围护结构耦合埋管换热系统运行策略研究

以某地铁车站为研究对象,模拟了其全年动态负荷,确定了地源热泵参数,建立了估算热泵出力及耗电量的参数模型,结合建立的动态换热模型得到了地源热泵系统-埋管阻容耦合仿真模型。以10年为运行周期,计算了埋管出水温度和换热量,分析了不同工况下的换热性能,提出了热泵机组联合冷却塔辅助换热的运行策略。结果显示:围护结构耦合埋管换热系统在长期运行工况下存在机组停机或机组出力不足的情况,当负荷为计算负荷的80%时,可以保证热泵机组出力满足需求;冷却塔联合运行策略在制冷季可以有效降低埋管出水温度,在过渡季冷却塔的免费冷量可以降低埋管出水温度1~2℃,在长期运行工况下具有较好的地温恢复效果。

光伏/光热三联供系统运行性能与优化研究

为消除太阳能随机性与不稳定性对建筑供能的不利影响,降低建筑运行能耗,基于TRNSYS建立PV/T耦合水源热泵与溴化锂吸收式制冷机三联供系统模型。以天津市某学生宿舍的太阳能三联供系统为研究对象,探究系统全年运行特性,以系统[火用]效率与投资回收周期为目标函数,以系统关键设备参数与运行参数作为决策变量,通过Grasshopper调用超体积估计算法(HypE)进行优化。研究结果表明,系统能够满足建筑负荷,采用PV/T与水源热泵耦合能够同时提升两者性能,PV/T产电能覆盖系统大部分能耗。优化结果表明,在最优条件下系统的[火用]效率为20.10%,投资回收周期为8.02年。PV/T耦合水源热泵与溴化锂吸收式制冷机系统能够达到更好的能效与经济性。研究结果可为太阳能三联供系统的设计提供理论依据。

光伏、光热与空气源热泵热水系统碳减排特性仿真与实测

我国生活热水供热品质、使用量逐步提升,其能耗在建筑节能发展过程中占比突显。为比较太阳能热利用、光伏电加热及空气源热泵热水系统的碳减排特性,本文建立了各类系统的性能化设计模型,并会同国家级检测中心开展了实测验证,分析了系统碳减排特性与室外环境温度、太阳辐照资源及运行控制策略的相关性。结果表明:严寒、寒冷地区低温环境显著影响太阳能集热保温和空气源热泵蒸发工况,在Ⅱ类太阳能资源区太阳能热水系统碳减排贡献更大;夏热冬冷、夏热冬暖地区空气源热泵性能最优,Ⅱ、Ⅲ类太阳能资源区受归一化温差影响,太阳能热利用时长和稳定性不及光伏电加热热水系统;光伏电加热热水系统受光伏组件效率影响,能源利用率不及太阳能热水系统,但通过增加光伏装机容量获得的节能收益提升最为显著。

高寒地区中深层地源热泵系统运行表现分析

对青海省共和县中深层地源热泵集中供暖系统实际运行情况展开了研究。通过室内外温度、取水与回灌水温度、供回水温度、能耗和性能系数等数据,综合分析了供热系统实际运行表现。研究结果表明,地热水出水温度存在0.078℃/d的衰减率,为维持地热动态平衡,取水上限流量为80 m 3/h。此外,天气转暖过程中室外平均温度5℃可看作热泵机组启停节点,关闭地源热泵机组仅靠板式换热器换热,能使系统综合性能系数最大升至8.7,系统能耗降幅达42.9%。本文可为地热供暖系统优化运行及能效提升提供参考。

基于GA-BP神经网络的地源热泵空调负荷预测及实例验证

针对当前建筑供热负荷预测模型预测精度低和能源利用率不高的问题,以及BP神经网络负荷预测方法存在的预测精度不高、易陷入局部最优等缺陷,采用GA-BP神经网络进行负荷预测。首先建立GA-BP神经网络模型,然后对采集到的数据进行处理,最后将该模型应用于北京某办公建筑的集中供热系统。验证数据显示,GA-BP神经网络负荷预测模型的总体平均相对误差为6.9%,预测的相对误差绝对值范围在6%~8%之间,显示出更高的预测精度。应用效果表明,GA-BP神经网络负荷预测模型相较于BP神经网络模型,能够更为精确地预测未来24h的逐时负荷。

高校食堂空气源热水系统的应用

以南通市某高校食堂项目为例,结合高校食堂的热水用水特点,对高校食堂热水热源、热水定额、冷水温度等各参数对高校食堂热水系统的影响进行探讨,并给出合理的取值建议。

结合空气源热泵能耗分析及光伏辅助的建筑供热设计方法

随着国家对北方地区冬季集中供热方式的普及,煤燃烧供暖方式造成的环境污染和能源消耗问题更加严重。为了优化北方建筑供热系统的能耗问题,研究设计了光伏辅助的空气源热泵供热系统。研究方法通过数值模拟构建了建筑能耗模型,结合供热需求优化了空气源热泵供热系统,增设了保温层和除霜模式。同时,研究评估了建筑供热系统的热负荷,以最小二乘法修正热泵的实际效能。并借助光伏供电方式协调了空气源热泵的能耗,结合供热系统的整体效益优化了供热控制系统。研究结果显示,光伏辅助的空气源热泵平均供热量可以达到23.74 kW,在模拟环境下的整体节能效益为77.19%~83.26%,相较于传统锅炉供热节能效益提升了59.24%。可见改进供热系统在同等制热效果下表现出更高的节能效益。因此,改进供热设计在节能效果上具有更高效的节能效果,为建筑供暖提供了一种环保节能的供热方式。

基于深度强化学习的空气源热泵供热系统温度控制策略

空气源热泵(air source heat pump,ASHP)负荷具备良好的可调节特性,其建模的准确性和控制策略的设计是充分发挥其调节潜力的关键。文中考虑空气源热泵供热系统的储热特性,提出了基于深度强化学习(reinforcement learning,RL)的空气源热泵供热系统温度控制策略。首先建立了基于参数辨识的空气源热泵供热系统数学模型。其次建立了空气源热泵供热系统马尔可夫过程决策模型,并基于Q-Learning算法设计了供热系统深度强化学习控制策略。基于实际运行数据的仿真结果表明,本文提出的考虑供热延迟的供热系统数学模型能够准确预测供回水温度及室内温度变化情况,且所提出的基于深度强化学习的温度控制策略能够在维持用户室内温度在设定值的前提下,有效降低用电成本。

基于FLOW HEAT的地下水源热泵一抽多灌井群优化布置数值研究

为研究一抽多灌井群的最佳布置方式,基于FLOW HEAT软件,将抽水井附近的灌水井群采用集中环绕型、直线型等8种不同布置方式建立数学模型,分析抽水井水温变化规律、温度和渗流场及最佳井距。结果表明,采用以抽水井为中心回灌井环绕布置方式时井群影响范围较小,渗流效果也较好,但抽水井水温较高易发生热贯通现象;采用直线型布置方式时抽水井水温变化较慢、井群渗流效果一般;井群水温随井距的增加逐渐降低。综合考虑,抽水井在回灌井中间的直线型布置且井距为51.63m为最佳布置方式。

Performance analysis of air-water dual source heat pump water heater with heat recovery

A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre-heated by waste hot water,then heated by the heat pump.Waste heat is recovered by first preheating the cold water and as water source of the heat pump.According to the correlated formulas of the coefficient of performance of air-source heat pump and water-source heat pump,and the gain coefficient of heat recovery-preheater,the formulas for the coefficient of performance of heat pump in six operating modes are obtained by using the dimensionless correspondence analysis method.The system characteristics of heat absorption and release associated with the heat recovery-preheater are analyzed at different working conditions.The developed approaches can provide reference for the optimization of the operating modes and parameters.The results of analysis and experiments show that the coefficient of performance of the device can reach 4-5.5 in winter,twice as much as air source heat pump water heater.The utilization of waste heat in the proposed system is higher than that in the system which only uses waste water to preheating or as heat source.Thus,the effect of energy saving of the new system is obvious.On the other hand,the dimensionless correspondence analysis method is introduced to performance analysis of the heat pump,which also has theoretical significance and practical value.

Data-driven sensitivity analysis and electricity consumption prediction for water source heat pump system using limited information

The studies on predicting the energy consumption of air conditioning systems are meaningful to building energy conservation and management. Generally, the more comprehensive the building information is, the easier the prediction model can be developed. However, it is very difficult to get detailed information about existing/old buildings (information-poor buildings), it is a big challenge to predict the energy consumption accurately by limited information. This study aims to predict the electricity consumption of the water source heat pump system of an office building based on meteorological data. The key variables are selected by error analysis and sensitivity analysis, and the effects of each variable on the models’ prediction performance can be obtained. Besides, the prediction models are established by support vector regression algorithm and trained by the local meteorological data. The results show that the positive and negative variables can be identified, and these positive variables are responsible for more than 70% of the total importance. Moreover, the root mean square error falls to 4.6044 from 7.8227 and the relative square error falls to 0.1494 from 0.4313 when the negative inputs are removed. And the errors reduce further to 4.1160 and 0.1194 by parameter optimization.

Experimental Study of Energy-Saving Air-Conditioner with Hot Water

Energy-saving air-conditioner with hot water is an air source heat pump air-conditioner,which can also supply hot water.The hot water is heated by a double pipe condenser connected with an air-cooled condenser in series in the system.This experiment of the energy-saving air-conditioner was carried out in the enthalpy-difference air-conditioner laboratory.The hot water temperature and the compressor's discharge and suction pressure were recorded in the working condition,where the ambient temperature was at 43 ℃,35 ℃,21 ℃,7 ℃,and 2 ℃ separately.The results showed that the system operated stably and reliably.This system can supply 240 L hot water at 50 ℃ in the whole year,and its coefficience of performance(COP)is much higher than the conventional air source heat pump system.Its energy conservation was proved by comparing the thermal efficiency with other sourece water heaters.

Water pumping analysis and experimental validation of beach well infiltration intake system in a seawater source heat pump system

Based on energy conservation equation and Darcy＇s law, a model of beach well infiltration intake system applied in a seawater source heat pump system was established. The model consists of the seawater seepage and the heat transfer process. A porous medium model in a software named FLUENT was applied to simulate the seepage and the heat transfer process. This model was also validated by field experiment conducted on the seashore in Tianjin, China. The maximum relative error between simulation results and experimental results was 2.1% （less than 5%）, which was acceptable in engineering applica- tion. The porosity and coefficient of thermal conductivity of the aquifer soil were determined to be 0.49 W/（m. K） and 1.46W/（m.K）, respectively in the simulation. In addition, the influencing factors of pumping water of beach well were also analyzed. The pumping water was found to increase when the distance between the beach well and the impervious boundary becomes longer, when the distance between the beach well and the supplying water source shortens, when the diameter of the beach well enlarges, and the drawdown enlarges.

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%。

光伏光热联合双源热泵系统运行模式研究(1):最佳切换模式验证

讨论了光伏光热联合双源热泵系统制热运行的最佳切换模式。利用TRNSYS软件建立了仿真模型,对双源(水源、空气源)热泵系统性能系数(COP_(s))进行了计算,提出以某时刻空气源热泵模式或水源热泵模式运行COP_(s)较大者优先运行作为COP_(s)切换模式。通过前期实验结果验证了模拟结果的正确性,并与常规的集热水箱温度切换模式进行了对比实验,验证了COP_(s)切换模式的有效性。结果表明,该实验系统以COP_(s)最佳切换模式运行时发电量和发电效率较集热水箱温度切换模式分别提高了5.35%和1.73%,耗电量降低了17.03%,COP_(s)提高了4.91%。

严寒地区空气源热泵耦合电磁能系统模拟运行研究

目的 为了促进空气源热泵耦合电磁能供热系统在严寒地区住宅建筑中的应用,研究该系统的运行性能和稳定性。方法 以沈阳地区某住宅建筑为例,应用Trnsys软件建立了空气源热泵耦合电磁能供热系统仿真模型,并用实测值对模型进行了验证;深入探讨空气源热泵耦合电磁能供热系统在供热期的运行特点,并与空气源热泵和电磁能供热系统分别进行比较。结果 空气源热泵耦合电磁能供热系统模型可靠,相对误差可以控制在15%以内;在供热期,室内平均温度可保持在17.97~21.84℃;空气源热泵耦合电磁能供热系统比电磁能供热系统的COP提高了59.17%,空气源热泵耦合电磁能供热系统CO_(2)减排量比空气源热泵和电磁能供热系统分别提高1.47%和59.50%。结论 空气源热泵耦合电磁能供热系统运行和COP变化更为稳定,系统环境效益更佳,室内热舒适性更高。