Thermodynamic and thermoeconomic optimization of a cooling tower-assisted ground source heat pump

Thermodynamic and thermoeconomic optimization of a cooling tower-assisted ground source heat pump (GSHP) in a multi-objective optimization process is performed. A thermodynamic model based on energy and exergy analyses is presented, and an economic model of the hybrid GSHP (HGSHP) system is developed according to the total revenue requirement (TRR) method. The proposed hybrid cooling tower-assisted GSHP system, including 12 decision variables, is considered for optimization. Three optimization scenarios, including thermodynamic single objective, thermoeconomic single objective, and multi-objective optimizations, are performed. In multi-objective optimization, both thermodynamic and thermoeconomic objectives are simultaneously considered. An optimization process is performed using the genetic algorithm (GA). In the case of multi-objective optimization, an example of a decision-making process for selection of the final solution from the Pareto optimal frontier is presented. The results obtained using the various optimization approaches are compared and discussed. Further, the sensitivity of optimized systems to the interest rate, the annual number of operating hours in cooling mode, the electricity price, and the water price are studied in detail. It is shown that the thermodynamic optimization is focused on provision for the limited source of energy, whereas the thermoeconomic optimization only focuses on monetary resources. In contrast, the multi-objective optimization considers both energy and monetary. Further, it is found that thermodynamic optimization is economical when the operating time in cooling mode is long and/or the electricity price is high, and water prices variations have no marked impact on the total product cost.     

Optimum thermoeconomic and thermodynamic performance characteristics of an irreversible three-heat-source heat pump

The coefficient of performance and specific heating load of an irreversible three-heat-source heat pump are given by using a general cycle model affected by the finite-rate heat transfer, heat leak and internal irreversibility of the cyclic working fluid. The heat pumping load divided by the total cost per unit time is taken as a new objective function and used to investigate the performance of the heat pump. The thermoeconomic and thermodynamic performance characteristics of the heat pump are discussed in detail. Some important performance parameters such as the thermoeconomic objective function and coefficient of performance are optimized. The optimally operating regions of the heat pump and the bounds of several performance parameters are determined. Finally, it is pointed out that the Carnot heat pump may be taken as a special case of a three-heat-source heat pump and consequently its optimal performance can be directly derived from the results obtained here.     

两级热电热泵的有限时间热力学分析

建立了考虑外部传热影响的两级半导体热电热泵模型，用有限时间热力学对牛顿传热规律下两级半导体热电热泵的性能进行分析，导出了供热率、供热系数与工作电流的一般关系式，得到了热电单元数的最优分配，并分析了多种因素对其性能的影响。     

基于溶液除湿的风冷热泵系统性能分析

为了克服利用冷却除湿的风冷热泵空调系统机器露点过低、需要再冷和过热、难以适应显热潜热比例的变化、不能蓄能等缺点,提出基于集热再生器溶液除湿的热泵空调系统。通过济南某工程实例研究表明,与冷却除湿空调系统相比较耗电量减少12.3%,利用太阳能加热溶液除湿具有降低空调除湿能耗、利用可再生能源、减少高品位能源消耗等优势。证明太阳能溶液除湿在空调系统中是处理潜热负荷的理想选择,具有较好的节能性。     

水源热泵空调系统运行优化

以采用水源热泵机组的某住宅小区为例,分析其建筑的冷热负荷特性,探讨其变化规律;对水源热泵机组、水泵系统、热源井的运行控制策略提出优化方案,为同类工程的节能运行提供参考。     

补燃型不可逆联合循环热机的性能分析

在原有的不可逆联合动力循环模型的基础上,建立了一个存在热阻、热漏、补燃、内不可逆性的定常流联合卡诺热机循环模型。研究其在补燃作用下的功率和效率特性并对其进行优化,导出功率、效率的基本优化关系,分析了补燃对最优性能的影响。     

地热水高温热泵及风机盘管系统的优化

针对60～85℃地热水的高温热泵及风机盘管供热空调系统,建立系统模型的目标函数;采用MATLAB软件求解出满足约束条件下的各级温度参数以及地热水第一、二级利用的最佳回水温度;从理论上分析了负荷侧供水温度对高温热泵价格和性能系数的影响。     

变频系统在单、双级组合式热泵空调系统中的应用

本文根据我国北方的地域特点,提出了一种单、双级定频-变频组合式混合热泵系统。这种热泵 在单、双级混合热泵系统的基础上,引入了变频系统,使之既能在夏季满足制冷要求,又能在冬季热泵采 暖中,在外界环境温度变化范围大的情况下高效节能地运行,同时还可提高系统的部分负荷性能,从而 提高了整个系统的能效比EER,增大了热泵的季节性能系数HSPF,是一种既节能又满足舒适性要求的 热泵系统。     

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.     

基于模糊控制的土壤源热泵系统研究

应用模糊控制技术,将土壤源热泵的两个水系统看成一个整体,以房间设定温度与实际温度的误差、冷却水侧供回水温差与设定温差的误差为输入参数,直接控制循环水泵的输入电流功率,进而控制水泵转速。避免了阀门开度变化引起的管网系统特性变化,最大程度地节省系统运行能耗。     

燃气机热泵的热力学分析

燃气机热泵是以燃气机作为动力来驱动的压缩式热泵。对燃气机热泵的热力学第一定律、Yong分析和能级平衡理论分析结果表明：其一次能源利用率可达1.76,Yong效率为0.291,能级平衡系数为0.394。与电动热泵等其他供热装置相比,燃气机热泵有着较高的热力学完善性,是一项高效节能技术。由于能级平衡理论分析考虑了Wu的作用,而热泵供暖时其性能系数的提高主要是利用了环境热量,所以建议采用能级平衡理论来分析评价热泵的性能。     

Performance analysis of an irreversible cogeneration heat pump cycle

An irreversible heat engine-driven vapour compression and absorption heat pump system is considered as a cogeneration cycle. The effects of thermal resistances and internal irreversibilities on the coefficient of performance (COP) of this cogeneration cycle were investigated using finite-time thermodynamic approach. An improved equation for the COP of the system under consideration was obtained. The results obtained here may serve as a good guide for the evaluation of existing real cogeneration heat pumps or provide some theoretical bases for the optimal design of future cogeneration heat pumps. © 1998 John Wiley & Sons, Ltd.     

Performance analysis of a closed regenerated Brayton heat pump with internal irreversibilities

This paper analyses the performance of a real heat pump plant via methods of entropy generation minimization or finite‐time thermodynamics. The analytical relations between heating load and pressure ratio, and between coefficient of performance (COP) and pressure ratio of real closed regenerated Brayton heat pump cycles coupled to constant‐ and variable‐temperature heat reservoirs are derived. In the analysis, the irreversibilities include heat transfer‐irreversible losses in the hot‐ and cold‐side heat exchangers and the regenerator, the non‐isentropic expansion and compression losses in the compressor and expander, and the pressure drop loss in the pipe and system. The optimal performance characteristics of the cycle may be obtained by optimizing the distribution of heat conductances or heat transfer surface areas among the two heat exchangers and the regenerator, and the matching between working fluid and the heat reservoirs. The influence of the effectiveness of regenerator, the effectiveness of hot‐ and cold‐side heat exchangers, the efficiencies of the expander and compressor, the pressure recovery coefficient and the temperature of the heat reservoirs on the heating load and COP of the cycle are illustrated by numerical examples. Published in 1999 by John Wiley & Sons, Ltd.     

“制冷、制热、卫生热水”型空气源热泵系统及分析

提出一种小型中央空调用“制冷、制热、卫生热水”型空气源热泵系统设计方案,能够利用空调部分冷凝热提供生活用卫生热水,该系统可与家用中央热水系统连接。     

Performance analysis of solar water heater combined with heat pump using refrigerant mixture

In the research presented in this paper the thermal performance of a solar water heater combined with a heat pump is studied. A solar collector was modified from corrugated metal roofing with a copper tube attached beneath. The performance of the solar water heater was tested, and models for the collector efficiency and storage tank were developed and used for the evaluation of their performance when combined with a heat pump system.     

Optimum allocation of heat exchanger inventory of irreversible air heat pump cycles

This study has determined the optimal ratios of heat conductance of a cold-side heat exchanger to that of a hot-side heat exchanger when the heating load and the coefficient of performance (COP) of the irreversible air heat pump cycles are taken as the optimization objectives. Both the optimum distributions of heat conductance corresponding to the maximum heating load and the maximum COP are less than 0.5 for the fixed total heat exchanger inventory. The influences of the heat reservoir temperature ratio, the total heat exchanger inventory, and the efficiencies of the compressor and expander on the optimum distribution of heat conductance and the maximum heating load and the maximum COP are analysed and shown by numerical examples.     

寒冷气候条件下耦合双级热泵制热性能实测与分析

建立耦合双级热泵制热系统,即设定空气源热泵作为一级预热机组,水源热泵机组作为二级制热机组,从而实现双级耦合制热。实验对空气源热泵在各种实际工况下运行的COP值进行测量与分析,当环境温度在-5℃时,若循环制热温度20℃左右．其COP值仍能够达到4;水-风式水源热泵机组在15～20℃水源循环进水温度时,能耗比（COP）值平均超过4;同时,实验还在对建型的耦合双级热泵装置进行实际测量的基础上．得出客观结论．即使在寒冷的气候条件下,双级热泵仍能够保持较高的节能效果和使用效果。     

地源热泵系统动态经济性分析

介绍地源热泵系统的基本原理,分析地源热泵技术的应用背景。利用费用现值法和年值法对地源热泵系统和空气源热泵系统的经济性进行计算,运用动态追加投资回收期公式得出地源热泵系统初投资的动态追加投资回收期。实例分析表明：地源热泵系统比传统空调系统运行费用低,具有明显的节能环保功效。     

一种基于排取热量平衡的地源热泵系统设计方法

地源热泵空调系统作为一种高效节能的空调系统,正得到日益广泛的应用.然而,由于建筑物的冷负荷及其运行时间往往大于供暖负荷及其运行时间,设计过程中往往取最不利情况下的负荷计算结果作为设计依据,排取热量的不平衡导致地温变化,最终影响空调运行性能.针对于此,提出了一种基于排取热量平衡的地源热泵系统设计方法.     

Thermodynamic and thermoeconomic analyses of an irreversible combined Carnot heat engine system

A combined cycle model which includes the irreversibilities of finite‐rate heat transfer in heat‐exchange processes and heat leak loss of the heat source is used to analyse the performance of a multi‐stage Carnot heat engine system. The efficiency, power output, ecological function and profit of operating the combined system are optimized. The optimally operating region of the combined system is determined. The optimal combined conditions between two adjacent cycles in the combined system are obtained. Moreover, the cycle model is generalized to include the internal irreversibilities of the working fluids so that the results obtained here become more general. Copyright © 2001 John Wiley & Sons, Ltd.