Title
Thermochemical heat storage - system design issues
Author
de Jong, A.J.
Trausel, F.
Finck, C.J.
van Vliet, L.D.
Cuypers, R.
Publication year
2014
Abstract
Thermochemical materials (TCMs) are a promising solution for seasonal heat storage, providing the possibility to store excess solar energy from the warm season for later use during the cold season, and with that all year long sustainable energy. With our fixed bed, vacuum reactors using zeolite as TCM, we recently demonstrated long-term heat storage with satisfactory output power. For domestic application, however, it will be necessary to considerably increase storage density and to reduce system costs. In this paper, we discuss issues on system, component and material levels for realizing a commercially attractive system. We first discuss a modular, fixed bed concept with a hot water storage. We show that with proper dimensioning of TCM modules and hot water storage, one can obtain a system where daily storage and on-demand heat delivery can be arranged by the hot water storage, while demands on output power, power control and material stability during operation are relaxed as much as possible. We also discuss atmospheric and central reactor concepts, which may provide lower-cost TCS systems. An important issue on component level is the implementation of a low temperature source providing evaporation heat in winter. We discuss several options, including the application of solar collectors in winter. Heat storage density can be increased by an order of magnitude by applying hydration reactions of hygroscopic salts, but this introduces physical and chemical stability issues during repeated cycles of hydration and dehydration. We discuss several of these stability issues as well as possible stabilization in a composite TCM, which should also provide sufficient vapor and heat transport.
Subject
TS - Technical Sciences
Fluid Mechanics Chemistry & Energetics
Built Environment
Buildings and Infrastructure
Thermochemical heat storage
Energy storage
Zeolite
Sodium sulfide
Thermochemical materials
Hydroscopic salts
PID - Process & Instrument Development EM - Energetic Material HTFD - Heat Transfer & Fluid Dynamics
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http://resolver.tudelft.nl/uuid:f129440a-0d31-408c-9e44-a8815286e278
TNO identifier
492331
Source
Energy Procedia, 48 (48), 309-319
Bibliographical note
Paper ook gepresenteerd op de SHC 2013, International Conference on Solar Heating and Cooling for Buildings and Industry September 23-25, 2013, Freiburg, Germany
Document type
article