Enhancement of heat and mass transfer in silica-expanded graphite composite blocks for adsorption heat pumps. Part II. Cooling system using the composite blocks

2000 ◽  
Vol 23 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Tai-Hee Eun ◽  
Hyun-Kon Song ◽  
Jong Hun Han ◽  
Kun-Hong Lee ◽  
Jong-Nam Kim
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Cooling System ◽  
Expanded Graphite ◽  
Heat Pumps ◽  
Adsorption Heat ◽  
Graphite Composite

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

Heat and Mass Transfer Characteristics in Consolidated Silica Gel/Water Adsorption–Cooling System

1997 ◽  
Author(s):  
Hideharu Yanagi ◽  
Nobumi Ino
Keyword(s):  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Silica Gel ◽  
Cooling System ◽  
Adsorption Heat ◽  
Overall Heat Transfer Coefficient ◽  
Operational Characteristics ◽  
Adsorption Cooling System ◽  
Desorption Cycle

The heat and mass transfer on adsorption beds is decisive for the operational characteristics of adsorption refrigerators. To overcome its heat and mass transfer limitations a consolidated silica gel adsorption heat exchanger has been designed and successfully developed. It was made of composite as 4.3 wt% graphite, 86.4 wt% silica gel and binders, which was pressed into a heat exchanger module and then dried under a temperature of 90°C for 24 hours. With use of this adsorption heat exchanger, we measured an overall heat transfer coefficient of 62.2 W/m2K at the beginning of desorption cycle and 61.5 W/m2K during desorption, respectively. Whereas corresponding values of a granular silica gel bed were 44.8 W/m2K and 25.9 W/m2K, respectively. This paper presents the operational characteristics of consolidated silica gel adsorption heat exchanger in refrigeration cycles, in addition to its isoster measurements for silica gel-water pair compared to that of the granular heat exchanger.

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.

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