Closed Adsorption Heat Storage—A Life Cycle Assessment on Material and Component Levels

Björn Nienborg,Peter Schossig,Rafael Horn,Gunther Munz,Dominik Fröhlich,Tobias Helling

doi:10.3390/en11123421

Björn Nienborg, Peter Schossig + Show 4 more

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https://doi.org/10.3390/en11123421

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Abstract

Closed adsorption storages have been investigated in several projects for heat storage in building applications with focus on energy density and performance. This study complements this research with the assessment of the environmental impacts over the life cycle. Global warming potential (GWP) was chosen as the assessment criterion. Selected sorption materials in combination with water as the refrigerant were analyzed first by themselves and then embedded in a generic storage configuration. Sensible storage in water served as the reference benchmark. Results on material and component level showed that the relative storage capacity compared to water under realistic operating conditions reached values of below 4 and 2.5, respectively, in the best cases. Since the effort for producing the sorbents as well as the auxiliary material demand for assembling storage components was significantly higher than in the reference case, the specific environmental impact per storage capacity also turned out to be ~2.5 to ~100 times higher. We therefore suggest focusing sorption storage research on applications that (a) maximize the utilization of the uptake of sorbents, (b) do not compete with water storages, and (c) require minimal auxiliary parts.

Highlights

The promotion and use of renewable energy sources is a key strategy for combating climate change.In order to match their fluctuating supply to the demand, energy storages play an essential role [1]
By using salt-impregnated matrixes, high values seem achievable: For materials with vermiculite as the substrate, values of up to 253 kWh/m3 and even 330 kWh/m3 have been reported, the latter analysis showed stability problems [9,10]. Even though these results indicate a great potential of solid sorption for thermal energy storage, their performance is significantly lower considering actual operating conditions
This paper focuses on the storage and provision of heat in temperature ranges suitable for building applications

Summary

Introduction

The promotion and use of renewable energy sources is a key strategy for combating climate change.In order to match their fluctuating supply to the demand, energy storages play an essential role [1]. In the field of heat storage, currently sensible hot water storages are widely used, especially for short-term energy storage. In regard to their extended use in combination with renewables, storage losses and space consumption are disadvantageous. Thermo-chemical materials (TCM) have been widely studied in the past couple of years, as they potentially allow higher storage densities and almost loss-free storage of thermal energy. The latter is the reason why they have been considered very promising for seasonal storage in combination with solar thermal energy [2]

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