A novel adsorption module with fiber heat exchangers: Performance analysis based on driving temperature differences. (September 2017)

• Record Type: Journal Article
• Authors: Wittstadt, Ursula; Füldner, Gerrit; Laurenz, Eric; Warlo, Alexander; Große, André; Herrmann, Ralph; Schnabel, Lena; Mittelbach, Walter
• Is Part Of: Renewable energy. Volume 110(2017)
• Page Start: 154
• Page End: 161
• Publication Date: 2017-09
• Subjects: Adsorption heat exchanger -- Adsorption heat pump -- Chiller -- Aluminum fiber composite -- SAPO-34 -- Driving temperature differences; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2016.08.061
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: A main focus of recent R&D on adsorption modules for thermally driven heat pumps and chillers has been to enhance the volume specific power output while maintaining a reasonable coefficient of performance (COP). An adsorption module using a new type of heat exchanger based on aluminum sintered metal fiber structures brazed on flat fluid channels has been developed. The heat exchangers for adsorber/desorber and evaporator/condenser are identically constructed. The adsorption heat exchanger is coated with a silico-alumino phosphate (SAPO-34) by a partial support transformation direct crystallization (PST) [1]. Both components are placed in a vacuum tight housing using a valve-free configuration. Water is used as adsorptive. The experimental characterization of the module shows a high volume specific power (up to 82 W/litre module for cooling, 320 W/litre for heating). Although no heat is recovered between ad- and desorption cycle, a COP of almost 0.4 is reached for cooling and 1.4 for heating. Driving temperature differences are defined for the analysis of the heat exchanger performance. The evaporator/condenser shows extremely good performance with about 240 W/K specific evaporation power per litre of heat exchanger, while the adsorber is limiting the module performance. Highlights: A novel adsorption module has been developed based on sintered aluminum fiber/SAPO-34 composites. The module shows a high volume specific power density at good COP values without heat recovery. An analysis of cyclic measurements at different temperatures gives insight in limitations and optimization potential.