Quasi-dynamic energy-saving judgment of electric-driven seawater source heat pump district heating system over boiler house district heating system

The electric-driven seawater source heat pump district heating system is a renewable energy utilization system, but this cannot guarantee the energy-saving effect of the system. The static energy-saving judgment between this system and the conventional boiler house district heating system was provided in a former research paper. However the static method has proved to be a very rough evaluation method and may lead to misjudgment as well. So a quasi-dynamic method, taking the total energy consumption during a whole heating season into consideration, is established in this paper. The energy-saving index turns out to be the expression of the lower limit of the average COP of the seawater source heat pump unit throughout the heating season (COP_h,mc). Then a case study is presented to show how the index of COP_h,mc and the actual average COP of the heat pump unit throughout the heating season (COP_h,ma) are calculated. The calculation results show that the quasi-dynamic method improves the calculation accuracy dramatically, and thus provides a better solution to the quantitative energy-saving evaluation of the electric-driven seawater source heat pump district heating system.     

Energy-saving judgment of electric-driven seawater source heat pump district heating system over boiler house district heating system

As a renewable energy utilization system, the electric-driven seawater source heat pump district heating system is gaining popularity in some coastal areas. However, under what conditions can the system achieve its energy-saving effect and how to evaluate its energy-saving potential are not clear in practice. In this paper, an expression of the critical COP value of the heat pump unit for energy-saving (COP_h,c) is derived through the comparison of the system and the conventional boiler house district heating system in the energy consumption respect. On the other hand, the actual COP values of the heat pump unit (COP_h,a) are calculated by an experimental data regression model on the basis of the manufacturer's dataset. The comparison of the values of COP_h,c and COP_h,a makes the energy-saving judgment of an electric-driven seawater source heat pump district heating system and its energy-saving potential, if it has, readily available. It was found that both the heating district radius and the natural conditions of the seawater are the most important factors that determine the energy efficiency of the system. And through comparison, it was also found that the type of the fuel of the boiler has significant impact on the crucial index value of COP_h,c.     

Verification of energy efficiency of district heating and cooling system by simulation considering design and operation parameters

This paper aims to verify the advantages of district heating and cooling (DHC) systems in terms of energy efficiency. From the measurement data, the parameters that characterize the energy efficiency of a heating/cooling plant are identified for DHC and an individual building. A simulation model that considers the difference in these parameters is developed. This model examines both the advantages and disadvantages of DHC systems and the effect of each parameter. The results show that the energy efficiency for cooling in DHC systems is superior to that in the case of individual cooling systems because of the “concentration effect” and “grade of operation”.     

燃气冷热电三联供与地源热泵的联合应用

以中新天津生态城能源站为例,分析了联合系统一次能源效率、燃料节约率、经济性、影响因素的敏感性和环保性等,结果表明,冷热电三联供系统的能源利用率可达88.9%,联合系统的能源消耗比常规系统少18.5%,冷热电三联供系统的初投资在6年内可以收回。     

海水源热泵区域供热系统最大供热半径的研究

在国家建筑节能设计标准中的耗电输热比EHR的基础上引申得到了热水循环泵输送能耗与系统供热量的一次能耗比EHR'指标,并根据对海水源热泵区域供热系统EHR'指标的不同控制要求,得到了系统的最大供热半径.经计算,当热水供回水温差为10℃,海水源热泵区域供热系统的EHR'指标分别控制在5%,10%,15%,20%时,系统的最大供热半径应分别为0.875,2.75,4.625,6.5 km.     

谈暖通空调节能问题与地源热泵的实际应用

针对暖通空调节能问题进行了研究,结合实际案例介绍了地源热泵在工程项目中的应用,通过与以城市供热为热源的室内散热器取暖方案进行对比分析,得出地源热泵系统能够有效解决空调系统节能问题,值得推广。     

无散热损失的热泵型供热系统研究

提出了一种可在环境温度下实现能量输运的供热系统。该系统利用吸收式热泵原理,以氨水为工作流体,发生器和冷凝器布置在热源端,而吸收器和蒸发器布置在热用户端,利用吸收器中溶液吸收蒸气所放出的吸收热来提供热能。由于采用质量分数不同的氨水作为能量载体,因此,可以在环境温度下实现能量输运,没有散热损失;同时,由于该系统利用潜热供热,大大减少了泵功耗。分析结果表明,当供热距离较远时,该系统具有明显优势。     

水源热泵系统在住宅供热空调中的应用

从基本原理及技术方案、经济分析等方面阐述了水源热泵系统在住宅供热空调中的应用，提出了中国水源热泵推广应用中存在的问题，对我国供热、环保和节能方面都有促进作用。     

地源热泵及地下蓄能系统的实验研究

采用系统能量平衡结合热传导方程建立二维温度场模型求解地下蓄能系统埋管换热器的全年动态传热特性。介绍了计算地下温度场的分布情况、单位埋管深度换热量、平均传热系数、进出地下埋管的水温和埋管换热器面积的方法。     

Optimal design of district heating and cooling pipe network of seawater-source heat pump

The district heating and cooling (DHC) system of a seawater-source heat pump is large system engineering. The investments and the operational cost of DHC pipe network are higher than a tradition system. Traditional design methods only satisfy the needs of the technology but dissatisfy the needs of the economy, which not only waste a mass of money but also bring problems to the operation, the maintenance and the management. So we build a least-annualized-cost global optimal mathematic model that comprises all constrict conditions. Furthermore, this model considers the variety of heating load and cooling load, the operational adjustment in different periods of the year. Genetic algorithm (GA) is used to obtain the optimal combinations of discrete diameters. Some operators of GA are selected to reduce the calculation time and obtain good calculation accuracy. This optimal method is used to the design of the DHC network of Xinghai Bay commercial district which is a real engineering. The design optimization can avoid the matter of the hydraulic unbalance of the system, enhance the running efficiency and greatly reduce the annualized-cost comparing with the traditional design method.     

中高温热泵辅助太阳能三联供系统的实验研究

本文建立了利用中高温热泵作为辅助方式的太阳能三联供实验系统,开发了基于触摸屏操作的系统数据采集及运行监控系统(SCADA),并进行了采暖性能实验。结果表明,在12月份每天10:00￣14:00范围内,太阳能可以单独进行采暖,其它时间需要辅助,高温水箱在正常运行时温度一般都维持在45℃左右,12月份实验系统的太阳能保证率为64.6%。在3月份太阳能一天的蓄热量可以达到83.5kWh,热泵工作的性能系数为4.21。     

空气源热泵-地板供暖系统测试分析

对青岛某空气源热泵+地板供暖系统运行数据进行了实测分析,结果表明该系统具有节能、舒适的特点。指出通过采用间歇运行和减小盘管间距等方法,可以进一步降低系统的运行费用。     

某医院热电冷三联供+集中供热技术方案研究

分析了某医院2004-2006年的热、电、冷负荷和天然气、蒸汽消耗情况,提出了热电冷三联供 集中供热的节能改造方案.分析结果表明,热电冷三联供 集中供热技术方案的安全性及经济效益较好,是一种合理可行的改造方案.     

地源热泵节能技术在苏州地区的应用

介绍了地源热泵中央空调系统的工作原理,将地源热泵中央空调系统与VRV系统中央空调系统进行对比,分析其在苏州地区运营的经济性和效果的舒适性,指出该空调系统环保、节能,适于在苏州地区推广应用。     

CO2跨临界水源热泵两级供热系统理论比较

在供热系统中，需要的水温较高时，由于回水温度高而导致CO2跨临界水源热泵能效比下降。如果降低回不温度，就要求不同温度的热水分级处理。CO2跨临界水源热泵两级供热系统可以实现能量的分级利用。分析对比了3种形工的CO2跨临界水源热泵两级供热系统，发现它们各有特点，可根据不同的使用要求采用适宜的两组系统。     

Comparison between design and actual energy performance of a HVAC-ground coupled heat pump system in cooling and heating operation

This work compares the experimental results obtained for the energy performance study of a ground coupled heat pump system with the design values predicted by means of standard methodology. The system energy performance of a monitored ground coupled heat pump system is calculated using the instantaneous measurements of temperature, flow and power consumption and these values are compared with the numerical predictions. These predictions are performed with the TRNSYS software tool following standard procedures taking the experimental thermal loads as input values. The main result of this work is that simulation results solely based on nominal heat pump capacities and performances overestimate the measured overall energy performance by a percentage between 15% and 20%. A sensitivity analysis of the simulation results to changes in percentage of its input parameters showed that the heat pump nominal coefficient of performance is the parameter that mostly affects the energy performance predictions. This analysis supports the idea that the discrepancies between experimental results and simulation outputs for this ground coupled system are mainly due to heat pump performance degradation for being used at partial load. An estimation of the impact of this effect in energy performance predictions reduces the discrepancies to values around 5%.     

四管热泵热回收型空调系统及其能耗分析

简要介绍了四管热泵热回收型空调系统的构造和运行，给出了用于评价整个系统综合性能的系统能效比的定义，分析了系统全年能效比随建筑冷热负荷比Ｋ的变化规律，指出在一定的Ｋ值范围内，四管热泵系统既能够满足不同用户的冷热需求，又能实现节能运行，能效比高于通常的双管热泵系统。     

氨水蓄能土壤源热泵集成系统工作过程的模拟研究

提出了以浅层土壤为热源/汇的氨水蓄能热泵集成系统,建立了系统工作过程动态数学模型。以长江流域某一办公建筑为例,对该系统夏季空调工况和冬季供暖工况进行了数值模拟。与以空气为热源/汇的氨水蓄能热泵集成系统进行了比较,结果显示以土壤为热源/汇的系统工作性能优于以空气为热源/汇的系统。     

浅谈地源热泵空调系统

介绍了地源热泵技术的概念及工作原理，对地下水热泵系统、地表水热系统等三种地源热泵空调的应用方式作了阐述，经与传统的中央空调作比较，提出了国内外地源热泵的发展前景。     

太阳能热水系统与地源热泵应用情况分析

对太阳能热水系统和地源热泵系统在工程实际中的应用情况进行了比较分析,分别就其工作原理、优缺点等作了论述,以期更有针对性的推广和应用这两种可再生能源系统。