Performance Optimization of a Combined Heat Pump Cycle

2003 ◽  
Vol 10 (04) ◽  
pp. 377-389 ◽  
Author(s):  
Lingen Chen ◽  
Yuehong Bi ◽  
Fengrui Sun ◽  
Chih Wu
Keyword(s):  
Heat Resistance ◽  
Steady Flow ◽  
Heat Pump ◽  
Performance Optimization ◽  
Coefficient Of Performance ◽  
Cycle Model ◽  
Heat Leakage ◽  
Heating Load ◽  
Internal Irreversibility ◽  
Optimal Heating

A steady flow combined heat pump cycle model with heat resistance, heat leakage and internal irreversibility is built in this paper. The optimal performance of the model is studied. The relation between optimal heating load and coefficient of performance (COP), as well as the maximum COP and the corresponding heating load are derived.

The Optimal Performance of a Carnot Heat Pump under the Condition of Mixed Heat Resistance

2002 ◽  
Vol 09 (03) ◽  
pp. 251-256 ◽  
Author(s):  
Xiaoqin Zhu ◽  
Lingen Chen ◽  
Fengrui Sun ◽  
Chih Wu
Keyword(s):  
Heat Resistance ◽  
Heat Pump ◽  
Optimal Performance ◽  
Coefficient Of Performance ◽  
Heating Load ◽  
Optimal Coefficient ◽  
The Relationship

The optimal performance of an endoreversible Carnot heat pump under the condition of mixed heat resistance is investigated. The relationship between the optimal coefficient of performance (COP) and the heating load is derived.

Model of irreversible finite-heat capacity heat reservoir absorption heat transformer cycle and its application

2007 ◽  
Vol 221 (12) ◽  
pp. 1643-1651 ◽  
Author(s):  
L Chen ◽  
X Qin ◽  
F Sun
Keyword(s):  
Performance Characteristic ◽  
Variable Temperature ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Working Fluid ◽  
Cycle Model ◽  
Heating Load ◽  
Internal Irreversibility ◽  
General Relations ◽  
Heat Transformer

An irreversible four-temperature-level absorption heat transformer cycle model with variable-temperature heat reservoirs is established, which considers the heat resistances between the heat reservoirs and the working fluid, the internal irreversibility due to internal dissipation of the working fluid, and the heat leakages between the heat reservoirs and the surrounding. The general relations between the heating load and the coefficient of performance are derived, and the general performance characteristic and the optimal performance characteristic are obtained using numerical examples. Moreover, the cycle model and the derived general relations are confirmed by comparing the prediction results of the model and engineering analysis results for real absorption heat transformer, and the cycle performance characteristic are discussed. The results obtained herein can provide some guidance for the optimal design of absorption heat transformer.

Heating load and COP optimisations for a universal steady flow endoreversible heat pump model

2011 ◽  
Vol 32 (2) ◽  
pp. 70-77
Author(s):  
Huijun Feng ◽  
Lingen Chen ◽  
Fengrui Sun ◽  
Chih Wu
Keyword(s):  
Steady Flow ◽  
Heat Pump ◽  
Heating Load

scholarly journals Optimization of absorption systems: case of the refrigerators and heat pumps

2019 ◽  
Vol Volume 30 - 2019 - MADEV... ◽  
Author(s):  
René Tchinda ◽  
Paiguy Armand Ngouateu Wouagfack
Keyword(s):  
Performance Optimization ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Entropy Generation Rate ◽  
Design Parameters ◽  
Working Fluid ◽  
Ecological Design ◽  
Ecological Performance ◽  
Heating Load ◽  
Main Components

The new thermo-ecological performance optimization of absorption is investigated by taking the ecological coefficient of performance ECOP as an objective function. ECOP has been expressed in terms of the temperatures of the working fluid in the main components of the system. The maximum of ECOP and the corresponding optimal temperatures of the working fluid and other optimal performance design parameters such as coefficient of performance, specific cooling load of absorption refrigerators, specific heating load of absorption heat pumps, specific entropy generation rate and the distributions of the heat exchanger areas have been derived analytically. The obtained results may provide a general theoretical tool for the ecological design of absorption refrigerators and heat pumps.

scholarly journals Performance Optimization of an Air-Standard Irreversible Dual-Atkinson Cycle Engine Based on the Ecological Coefficient of Performance Criterion

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Guven Gonca ◽  
Bahri Sahin
Keyword(s):  
Performance Optimization ◽  
Pressure Ratio ◽  
Performance Criterion ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Temperature Ratio ◽  
Finite Rate ◽  
Ecological Performance ◽  
Atkinson Cycle ◽  
Internal Irreversibility

This paper presents an ecological performance analysis and optimization for an air-standard irreversible Dual-Atkinson cycle (DAC) based on the ecological coefficient of performance (ECOP) criterion which includes internal irreversibilities, heat leak, and finite-rate of heat transfer. A comprehensive numerical analysis has been realized so as to investigate the global and optimal performances of the cycle. The results obtained based on the ECOP criterion are compared with a different ecological function which is named as the ecologic objective-function and with the maximum power output conditions. The results have been attained introducing the compression ratio, cut-off ratio, pressure ratio, Atkinson cycle ratio, source temperature ratio, and internal irreversibility parameter. The change of cycle performance with respect to these parameters is investigated and graphically presented.

Optimal Performance of an Endoreversible Four-Heat-Reservoir Absorption Heat-Transformer

2004 ◽  
Vol 11 (02) ◽  
pp. 147-159 ◽  
Author(s):  
Xiaoyong Qin ◽  
Lingen Chen ◽  
Fengrui Sun ◽  
Chih Wu
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Heat Transfer Surface ◽  
Coefficient Of Performance ◽  
Heat Reservoir ◽  
Cycle Model ◽  
Surface Areas ◽  
Heating Load ◽  
Temperature Levels ◽  
Heat Transformer

Based on an endoreversible absorption heat-transformer cycle model operating between four temperature levels with linear (Newtonian) heat transfer law, the fundamental optimal relation between the specific heating load and the coefficient of performance, the optimal temperatures of the working substance, and the optimal heat transfer surface areas of the four heat exchangers are derived by using finite-time thermodynamics. Moreover, the effects of the cycle parameters on the cycle characteristic are studied by numerical examples. The results obtained herein can provide some guidance for the optimal design of absorption heat-transformers.

Performance optimization of an air source heat pump water heater using mathematical modelling

2015 ◽  
Vol 26 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Stephen Tangwe ◽  
Michael Simon ◽  
Edson L. Meyer ◽  
Sampson Mwampheli ◽  
Golden Makaka
Keyword(s):  
Ambient Temperature ◽  
Heat Pump ◽  
Performance Optimization ◽  
Rate Of Change ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Tank ◽  
Water Heater ◽  
Conservation Of Energy ◽  
Air Source Heat Pump

In South Africa, there is an ongoing constraint on the electricity supply at the national grid to meet the demand. Eskom is implementing various measures such as the Integrated Demand Management and the promotion and encouragement of the use of energy efficient devices like an Air Source Heat pump (ASHP) water heater to replace the high electrical energy consuming conventional geysers for sanitary hot water production. The ASHP water heater market is fast gaining maturity. A critical mathematical model can lead to performance optimization of the systems that will further result in the conservation of energy and significant reduction in global warming potential. The ASHP water heater comprises of an ASHP unit and a hot water storage tank. In this study, a data acquisition system (DAS) was designed and built which monitored the energy used by the geyser and the whole building, the temperature at the evaporator, condenser, tank outlet hot water, tank inlet cold water, the ambient temperature and relative humidity in the vicinity of the ASHP evaporator. It is also worthy to mention that the DAS also included to a flow meter and two additional temperature sensors that measured the volume of water heated and inlet and outlet water temperature of the ASHP. This work focused on using the mathematical equation for the Coefficient of Performance (COP) of an ideal Carnot’s heat pump (CHP) water heater to develop basic computation in M-file of MATLAB software in order to model the system based on two reservoir temperatures: evaporator temperatures (Tevp) of 0°C to 40°C (approximated to ambient temperature, Ta) and condenser temperatures (TCon) set at 50°C, 55°C and 60°C (approximated to the hot water set temperature of 50°C, 55°C and 60°C) respectively. Finally, an analytical comparison of a CHP water heater to the practical ASHP water heater was conducted on a hot water set point temperature of 55°C. From the modelling results, it can be deduced that at 0°C Tevp, the COP was 5.96 and 2.63 for CHP and ASHP water heater respectively, at a hot water set temperature of 55°C. Above 20°C Tevp, the rate of change of COP increased exponentially for the ideal CHP system, but was constant at 0.01/°C for the practically modelled ASHP water heater.

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