In the context of the FW project "Restwärmenutzung durch intelligente Speicher- und Verteilungssysteme (Utilization of Waste Heat by Intelligent Storage and Distribution Systems)", various kinds of heat storage technologies (sensible, latent, and chemical) were analysed and evaluated. For automotive applications, the chemical heat storage based on reversible processes provides a promising approach. At the temperature level up to 100 °C, the chemical heat storage based on salt hydrates like sodium sulphide or calcium chloride has the highest potential. During extensive preliminary investigations, different material combinations in a temperature range from -15 °C to 20 °C were tested. In this connection, ethanol proved to be an inappropriate reaction partner, whereas exothermic reactions with methanol were confirmed. In addition, it was shown that the preparation of the material had a great influence on the course of reaction. in the next step a heat storage prototype was designed and constructed to carry out investigations in vehicle-related conditions (heat capacity, installation space). The energy density of the measurements determined using sodium sulphide methylate is currently only one-third of the theoretical maximum values of this absorber material, the energy density of calcium chloride about one-fifth. The causes of for these significant deviations could be verified on the experimental set-up: Reduced intercalation of sorbate molecules during the absorption process, heat losses due to the massive construction of the storage, Change of the sorbate from water to methanol, Slight decomposition of the material. Considering the optimization potential, the energy density can be increased accordingly and the advantages of a lossless storage as well as the possibility of vehicle cooling could be realized. Thus, this system seems very attractive to climatize the cabin and it can also bring fuel consumption benefits in driving cycles, for example, cold starts at the NEDC, standstill phases at the WLTP or during the MACtest.
Chemical heat storage for automotive heating and cooling applications
2013
17 Seiten, 11 Bilder, 1 Tabelle, 19 Quellen
Conference paper
English
Heat storage devices for automotive applications
Automotive engineering | 1987
|Heating and heat storage processing method based on automotive heat management system and automobile
European Patent Office | 2023
|Chemical hydrogen storage material property guidelines for automotive applications
Online Contents | 2015
|SAE Technical Papers | 2016
|