scholarly journals Influence of desorption temperature on the thermodynamic performance of adsorption heat pump

2018 ◽  
Vol 70 ◽  
pp. 01022
Author(s):  
Katarzyna Zwarycz-Makles
Keyword(s):  
Heat Pump ◽  
Heat Pumps ◽  
Adsorption Heat ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Thermodynamic Efficiency ◽  
Efficiency Coefficient ◽  
Desorption Temperature ◽  
Adsorption Heat Pump ◽  
Thermodynamic Performance

In the paper an analysis of the desorption temperature effect on the thermodynamic efficiency of the adsorption heat pumps is presented. The thermodynamic performance of heat pump is determined by Coefficient of Performance (COP) as well as exergetic efficiency coefficient (ηex) at the adsorption equilibrium conditions and compared to the performance at heat of evaporation of the working fluid conditions. Possible estimation of reduced efficiency of adsorption silica gel/water heat pump, as distinct from the equilibrium efficiency in realistic technical system is presented.

scholarly journals Modeling the Performance of Water-Zeolite 13X Adsorption Heat Pump

2017 ◽  
Vol 38 (4) ◽  
pp. 191-207 ◽  
Author(s):  
Kinga Kowalska ◽  
Bogdan Ambrożek
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Pump ◽  
Heat Pumps ◽  
Adsorption Heat ◽  
Coefficient Of Performance ◽  
Desorption Kinetics ◽  
Zeolite 13X ◽  
Adsorption Heat Pump

Abstract The dynamic performance of cylindrical double-tube adsorption heat pump is numerically analysed using a non-equilibrium model, which takes into account both heat and mass transfer processes. The model includes conservation equations for: heat transfer in heating/cooling fluids, heat transfer in the metal tube, and heat and mass transfer in the adsorbent. The mathematical model is numerically solved using the method of lines. Numerical simulations are performed for the system water-zeolite 13X, chosen as the working pair. The effect of the evaporator and condenser temperatures on the adsorption and desorption kinetics is examined. The results of the numerical investigation show that both of these parameters have a significant effect on the adsorption heat pump performance. Based on computer simulation results, the values of the coefficients of performance for heating and cooling are calculated. The results show that adsorption heat pumps have relatively low efficiency compared to other heat pumps. The value of the coefficient of performance for heating is higher than for cooling

Development of a µ-Scale Turbine Expander for Energy Recovery

2009 ◽  
Author(s):  
Marcus Keding ◽  
Piotr Dudzinski ◽  
Martin Tajmar ◽  
Reinhard Willinger ◽  
Klaus Ka¨fer
Keyword(s):  
Heat Pump ◽  
Pressure Difference ◽  
Energy Recovery ◽  
Low Pressure ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Low Flow ◽  
Working Fluid ◽  
Small Scale ◽  
Work Recovery

Waste heat is a primary source of energy loss in many applications. A number of developments around a micro rocket engine at the Austrian Research Centers (ARC) promise innovative energy recovery and micro power generation solutions. Here we focus on the investigation of micro technologies for application in HVAC (heating, ventilating, and air conditioning) systems. The use of μ-scale turbine expanders for work recovery in transcritical CO2 heat pump processes has been identified as most interesting and promising for the application in HVAC cases. One of the main drawbacks of transcritical CO2 heat pumps is the lower COP (coefficient of performance) compared to conventional heat pump systems which originates from the non isothermal heat rejection in the gas cooler. This drawback can be compensated by utilizing the pressure difference between the high pressure and low pressure part of the heat pump for work recovery. This is feasible as the pressure difference is considerably larger in case of CO2 heat pumps compared to conventional systems. Work recovery can be realized by substituting the expansion valve between the high and low pressure side by an expansion machine. Due to the low flow rate of the working fluid, the turbine type is based on the Pelton turbine with specific two phase flow turbine blades. In addition to the turbine part a magnetic coupling, miniature bearings and a small scale generator are important parts of the system. Thermodynamic simulations showed an absolute microturbine power yield between 60 W and 150 W for a 2 kW heating system.

scholarly journals Parametric Investigation of a Ground Source CO2 Heat Pump for Space Heating

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3563
Author(s):  
Evangelos Bellos ◽  
Christos Tzivanidis
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Pumps ◽  
Geothermal Field ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Space Heating ◽  
Geothermal System ◽  
Parametric Investigation ◽  
Ground Source

The objective of the present study is the parametric investigation of a ground source heat pump for space heating purposes with boreholes. The working fluid in the heat pump is CO2, and the geothermal field includes boreholes with vertical heat exchangers (U-tube). This study is conducted with a developed model in Engineering Equation Solver which is validated with data from the literature. Ten different parameters are investigated and more specifically five parameters about the heat pump cycle and five parameters for the geothermal unit. The heat pump’s examined parameters are the high pressure, the heat exchanger effectiveness, the temperature level in the heater outlet, the flow rate of the geothermal fluid in the evaporator and the heat exchanger thermal transmittance in the evaporator. The other examined parameters about the geothermal unit are the ground mean temperature, the grout thermal conductivity, the inner diameter of the U-tube, the number of the boreholes and the length of every borehole. In the nominal design, it is found that the system’s coefficient of performance is 4.175, the heating production is 10 kW, the electricity consumption is 2.625 kW, and the heat input from the geothermal field is 10.23 kW. The overall resistance of the borehole per length is 0.08211 mK/W, while there are 4 boreholes with borehole length at 50 m. The parametric analysis shows the influence of the ten examined parameters on the system’s performance and on the geothermal system characteristics. This work can be used as a reference study for the design and the investigation of future geothermal-driven CO2 heat pumps.

Analysis of Two-Phase Flow Solar Collectors With Application to Heat Pumps

1982 ◽  
Vol 104 (4) ◽  
pp. 358-365 ◽  
Author(s):  
S. K. Chaturvedi ◽  
Y. F. Chiang ◽  
A. S. Roberts
Keyword(s):  
Heat Pump ◽  
Thermal Performance ◽  
Two Phase Flow ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Phase Flow ◽  
Solar Collectors ◽  
Ambient Conditions ◽  
Two Phase

A thermodynamic model is developed to analyze the thermal performance of two-phase solar collectors. The well-known equilibrium homogeneous theory is used to model the two-phase flow in the solar collectors. The resultant set of coupled ordinary differential equations for saturated pressure and quality of working fluid in the collector tubes are solved by an iterative procedure using a fourth-order Runge-Kutta method. The results are then applied to determine the thermal performance of a solar assisted heat pump which uses two-phase flow collectors as the evaporator. The results indicate that even with the use of less expensive bare solar collectors as evaporator for the heat pump, the heating coefficient of performance (COPH) as high as 6 can be obtained under realistic ambient conditions provided a proper matching exists between the collector’s evaporative capacity and the compressor’s pumping capacity.

scholarly journals Modeling and Simulation of Combined Heat and Mass Transfer in Zeolite SAPO-34 Coating for an Adsorption Heat Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Imen Amari ◽  
M. H. Chahbani
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Pump ◽  
Adsorption Heat ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Experimental Database ◽  
Energy Technologies ◽  
Adsorption Heat Pump ◽  
Mass Transfers

Heat and mass transfers inside an adsorbent bed of an adsorption heat pump (AHP) are considered poor; consequently, they can cause low system performance. They should be enhanced so as to increase the coefficient of performance of the cooling machine. The aim of this work is to study an adsorbent bed coated with the zeolite SAPO-34. A simulation model based on governing equations for energy, mass, and momentum transfers is developed using COMSOL Multiphysics software. The system zeolite SAPO-34/water has been considered. Modeling results are validated by experimental database available at the Institute for Advanced Energy Technologies “Nicola Giordano,” Italy. It has been shown that the adsorption heat pump performance is affected by both heat and mass transfer. The enhancement of heat transfer solely is not sufficient to attain high values of specific cooling power. In the case of water vapor/SAPO-34 pair, mass transfer has a significant impact on the duration of the cooling step which should be shortened if one would want to increase the specific cooling power. The sole way to do it is to enhance mass transfer inside porous adsorbent.

Performance of a Thermoelectric Adsorption Heat Pump Vis-à-Vis Thermoelectric Device and Adsorption Heat Pump for Electronics Cooling Applications

2012 ◽  
Author(s):  
Ashish Sinha ◽  
Yogendra Joshi
Keyword(s):  
Mathematical Models ◽  
Heat Pump ◽  
Temperature Difference ◽  
Electronics Cooling ◽  
Heat Pumps ◽  
Adsorption Heat ◽  
Thermoelectric Device ◽  
Adsorption Heat Pump ◽  
Heat Regeneration ◽  
Adsorption Cycle

Performance of ‘ThermoElectric (TE)’, ‘ThermoElectric-Adsorption (TEA)’ and Adsorption heat pumps has been compared, theoretically, for identical conditions. The TEA heat pump uses TE devices to drive heat regeneration for its adsorption cycle. While this increases the COP of the TEA heat pump, it also highlights the need to investigate if a TE device, when applied alone, could have outperformed the TEA and the Adsorption heat pumps. This becomes important in the context of cooling applications that only require cooling of a few degrees below ambient, and in cases where the ambient environment is thermally harsh. In the first context the TE devices pump heat across a lesser temperature difference with good COP that may outweigh the COP of a TEA or an Adsorption heat pump, in the second, the performance of TE device deteriorates due to high temperatures, and gains in overall COP of TEA heat pump due to heat regeneration become marginal. A heat rejection temperature range of 50 to 200 °C is considered for this investigation. Mathematical models for formulation of the COP of these systems are constructed and compared. It is observed that a TE device is preferable for cooling 20–30°C below the ambient. Beyond this range a TEA chiller is a good option.

Finite-Time Thermodynamic Performance for a Class of Irreversible Heat Pumps

1997 ◽  
Author(s):  
Chih Wu ◽  
Lingen Chen ◽  
Fengrui Sun
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Pump ◽  
Finite Time ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Heat Leak ◽  
Thermodynamic Performance ◽  
The Relationship

The effect of heat resistance and heat leak on the performance of irreversible heat pumps using a generalized heat transfer law is analyzed in this paper. The relationship between the optimal cooling load and the cop (coefficient of performance) for a steady-state irreversible heat pump is derived.

Development and Experimental Study of New Working Fluids for Moderate-High-Temperature Heat Pumps

2012 ◽  
Vol 468-471 ◽  
pp. 1313-1321
Author(s):  
Shi Jie Liu ◽  
Wen Sheng Yu ◽  
Wu Chen
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Working Fluids ◽  
Heating Efficiency ◽  
Temperature Heat ◽  
Performance Results ◽  
High Temperature Heat Pump

Some suggestions for developing new working fluids for moderate-high-temperature heat pump with excellent thermal and environmental performance were given firstly in this paper. The theoretical and experimental performance analysis of new-developed working fluids M1-M6 was carried out. The theoretical performance results showed that M1-M6 had high heating efficiency and GWP (Global Warming Potential) of M2 was less than 150. The experimental results showed that M5 had higher thermal efficiency than other two working fluids under same working condition. At the ambient temperature respectively of 30 Centigrade Degree and 40 Centigrade Degree, it took 70 and 65 minutes by the heat pump charged with M5 as working fluid to heat 100 liters of water respectively from 30 Centigrade Degree to 80 Centigrade Degree. Meanwhile the system’s COP (Coefficient of Performance) was respectively 2.9 and 3.0.

Experimental Study on the Performance of a Hybrid Water Heater

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Lihua Dong ◽  
Yuko Suzuki ◽  
Noriyuki Kobayashi
Keyword(s):  
Experimental Study ◽  
Heat Pump ◽  
Process Simulation ◽  
Adsorption Heat ◽  
Coefficient Of Performance ◽  
Heat Sources ◽  
Water Heater ◽  
Heat Pump Water Heater ◽  
Adsorption Heat Pump ◽  
Domestic Use

We study a hybrid adsorption heat pump water heater for domestic use that comprises a water heater with dual heat sources. This water heater combines the advantages of an adsorption heat pump and a conventional gas boiler. An experimental study on the output and coefficient of performance (COP) of the system was performed under various environmental conditions, and some important conclusions and suggestions that improved the hybrid water heater system are presented. In addition, a numerical analysis for experimental results was presented by process simulation, and then the COP of the system was examined.

scholarly journals Heat Pump Bridge Analysis Using the Modified Energy Transfer Diagram

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 137
Author(s):  
Florian Schlosser ◽  
Heinrich Wiebe ◽  
Timothy G. Walmsley ◽  
Martin J. Atkins ◽  
Michael R. W. Walmsley ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Heat Pump ◽  
Heat Recovery ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Combined Application ◽  
Recovery Potential ◽  
Composite Curve ◽  
And Performance ◽  
The Individual

Heat pumps are the key technology to decarbonise thermal processes by upgrading industrial surplus heat using renewable electricity. Existing insight-based integration methods refer to the idealised Grand Composite Curve requiring the full exploitation of heat recovery potential but leave the question of how to deal with technical or economic limitations unanswered. In this work, a novel Heat Pump Bridge Analysis (HPBA) is introduced for practically targeting technical and economic heat pump potential by applying Coefficient of Performance curves into the Modified Energy Transfer Diagram (METD). Removing cross-Pinch violations and operating heat exchangers at minimum approach temperatures by combined application of Bridge Analysis increases the heat recovery rate and reduce the temperature lift to be pumped at the same time. The insight-based METD allows the individual matching of heat surpluses and deficits of individual streams with the capabilities and performance of different market-available heat pump concepts. For an illustrative example, the presented modifications based on HPBA increase the economically viable share of the technical heat pump potential from 61% to 79%.

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