A novel approach to enhance heat and mass transfer in adsorption heat pumps using the zeolite–water pair

1999 ◽  
Vol 27 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Melkon Tatlıer ◽  
Birgül Tantekin-Ersolmaz ◽  
Ayşe Erdem-Şenatalar
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Pumps ◽  
Adsorption Heat ◽  
Novel Approach

Experimental study of 3D – structured adsorbent composites with improved heat and mass transfer for adsorption heat pumps

2021 ◽  
pp. 133365
Author(s):  
Marc Scherle ◽  
Timothy A. Nowak ◽  
Stefan Welzel ◽  
Bastian J.M. Etzold ◽  
Ulrich Nieken
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Heat And Mass Transfer ◽  
Heat Pumps ◽  
Adsorption Heat

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

Design of Microscale Heat and Mass Exchangers for Absorption Space Conditioning Applications

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Ananda Krishna Nagavarapu ◽  
Srinivas Garimella
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Flow Distribution ◽  
Mass Transfer Process ◽  
High Heat ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Pressure Drops ◽  
Transfer Rates ◽  
Small Absorption

This paper presents the development of a miniaturization technology for heat and mass exchangers used in absorption heat pumps. The exchanger consists of an array of parallel, aligned alternating shims with integral microscale features, enclosed between cover plates. These microscale features facilitate the flow of the various fluid streams and the associated heat and mass transfer. In an absorber application, effective vapor and solution contact and microscale features for the flow of both the solution and the coolant induce high heat and mass transfer rates without any active or passive surface enhancement. The geometry ensures even flow distribution with minimal overall pressure drops. A model of the coupled heat and mass transfer process for ammonia-water absorbers using this configuration under typical operating conditions demonstrates the potential for extremely small absorption components. The proposed concept is compact, modular, versatile, and in an eventual implementation, can be mass produced. Additionally, the same concept can be extended to the other absorption heat pump components as well as for several other industries involved in multicomponent fluid processes.

Use of the Linear Driving Force Approximation in Adsorption Heat Pump and Chiller Modeling

2009 ◽  
Author(s):  
Alex Raymond ◽  
Srinivas Garimella
Keyword(s):  
Mass Transfer ◽  
Driving Force ◽  
Waste Heat ◽  
Heat Pumps ◽  
Adsorption Heat ◽  
Activated Carbon Fiber ◽  
Fickian Diffusion ◽  
Half Cycle ◽  
Linear Driving Force ◽  
Adsorption Heat Pump

Adsorption heat pumps and chillers can utilize solar or waste heat to provide space conditioning, process heating or cooling, or energy storage. In these devices, accurate modeling of intraparticle adsorbate mass transfer is an important part of predicting overall performance. The linear driving force (LDF) approximation is often used for modeling intraparticle mass transfer in place of the more detailed Fickian diffusion (FD) equation for its computational simplicity. This paper directly compares the adsorbate contents predicted by the conventional LDF approximation, an empirical LDF approximation proposed by El-Sharkawy et al. [1], and the FD equations for cylindrical adsorbent fibers such as activated carbon fiber (ACF). The conditions under which the LDFs agree with the FD equation are then evaluated. It is shown that for a given working pair, agreement between the LDF and FD equations is affected by the diffusivity, particle radius, half-cycle time, initial adsorbate content, and equilibrium adsorbate content. The maximum possible error in adsorbate content predicted by the LDF approximation compared with the FD solution is then calculated for the ACF (A-20)-ethanol working pair. Although the maximum error will be different for other cases, the technique used in this paper can be reproduced to determine the greatest possible LDF error for any working pair.

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