Verification of hydrothermal stability of adsorbent materials for thermal energy storage

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experimental comparison of two heat exchanger concepts for latent heat storage applications

Abstract In the present work, two different types of heat exchangers are experimentally compared, namely a fin-and-tubes custom made HEX and a commercial asymmetric plate heat exchanger, for the application with phase change materials. In particular, the two devices were tested in a specifically designed testing rig located at CNR-ITAE and suitable for the characterization of thermal energy storages. The testing bench allows simulating a heat source up to 100°C (e.g. solar thermal collectors, low-grade waste heat) and to set the desired discharge temperature in the range 20°C-80°C. The phase change material with which the exchangers were filled, is a commercial paraffin (Plus ICE A82), having a nominal melting temperature of 82°C. The experimental results on charge and discharge tests, realized with the same protocol, were used for a comparison of the systems, through the identification of suitable performance figures and Key Performance Indicators, such as material-to-metal ratio, heat storage density, maximum and average power achievable and effectiveness of the system. The results show that, for the tested material, characterised by a very low thermal conductivity (i.e. about 0.2 W/mK), the selected plate heat exchanger allows a better exploitation of the heat stored inside the material, letting at the same time to reach a power output in the range 1-10 kW

Enabling technologies for sector coupling: A review on the role of heat pumps and thermal energy storage

In order to reduce greenhouse gas emissions, current and future energy systems need to be made more efficient and sustainable. This change can be accomplished by increasing the penetration of renewable energy sources and using efficient technologies in energy generation systems. One way to improve the operation of the whole energy system is through the generation and end-use sector coupling. Power-to-heat energy conversion and storage technologies, in this view, are enabling technologies that can help in balancing and improving the efficiency of both thermal and electric grids. In the present paper, a comprehensive analysis of the role of heat pumps and thermal energy storage for sector coupling is presented. The main features of the analyzed technologies are presented in the context of smart electric grid, district heating and cooling and multi-carrier energy systems, and recent findings and developments are highlighted. Finally, the technical, social, and economic challenges in the adoption of investigated technologies are discussed.This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31—MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades—Agencia Estatal de Investigación (AEI) (RED2018-102431-T). The authors at the University of Lleida would like to thank the Catalan Government for the quality accreditation given to her research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia program

Model development and validation for a tank in tank water thermal storage for domestic application

5noThe hot water tanks are the typical thermal storage systems in Solar Domestic Hot Water (SDHW) plants. In this paper a new model for ESP-r has been developed, in order to simulate a tank in tank heat storage. The tank in tank system is made up of two tanks in which the smaller, storing potable hot water, is contained in a larger buffer filled with heating-circuit water. The developed model is an enhanced version of a component already available in ESP-r. Experimental results are used to identify some parameters and to perform the validation of the developed code.openopenPadovan, Roberta; Manzan, Marco; Zandegiacomo De Zorzi, Ezio ; Gullì, Giuseppe; Frazzica, AndreaPadovan, Roberta; Manzan, Marco; ZANDEGIACOMO DE ZORZI, Ezio; Gullì, Giuseppe; Frazzica, Andre

dynamic simulation of a multi generation system for electric and cooling energy provision employing a sofc cogenerator and an adsorption chiller

Abstract Aim of this work is the dynamic simulation of the operation of a small-scale multi-generation system, based on a Solid Oxide Fuel Cell (SOFC) micro-cogenerator (μCHP) coupled to an adsorption chiller, to provide electric and cooling energy to a telecommunication shelter. The dynamic simulation model has been implemented in TRNSYS environment. The μCHP has nominal electric power of 2.5 kW and its thermal output is used to drive a thermally driven adsorption chiller, with nominal cooling power of 10 kW. The performance of both components were experimentally validated under controlled lab conditions. The developed model allowed to optimize the system configuration and to perform an energy and environmental analysis. This analysis demonstrated the possibility of achieving global energy efficiency up to 63% with a CO2 reduction proportional to the electric and cooling load of the telecommunication shelter

Experimental testing of a hybrid sensible-latent heat storage system for domestic hot water applications

Aim of this work is to present the results of the testing of a small scale hybrid sensible/latent storage system (nominal volume 48.6 dm3), consisting of water in which macro-encapsulated phase change materials (PCMs) are added. Two different PCMs were macro-encapsulated, a commercial paraffin and a hydrate salts mixture prepared in the CNR ITAE lab, and loaded inside the tank in order to be tested. Different volume ratios between the PCM and the water were tested. The tests were conducted simulating different domestic hot water draw-off profiles. The resulting data showed an appreciable increase of heat storage capacity per unit of volume, even for limited fractions of PCM employed, reaching up to 10% of heat storage increasing by 1.3 dm3 of hydrate salts mixture added. Finally, the experimental results were used to test a numerical method of a PCM enhanced tank for dynamic plant simulations in ESP-r environment