International Journal of Waste Resources

Heat battery technologies for waste heat utilization for low carbon processes and automotive use

8^th World Congress and Expo on Recycling

June 25-26, 2018 | Berlin, Germany

Noriyuki Kobayashi

Nagoya University, Japan

Posters & Accepted Abstracts: Int J Waste Resour

Abstract:

Thermochemical heat battery is one of heat management technology that shows potential for reducing waste heat and fuel consumption. The system stores a working medium utilize waste heat by repetitive heat charging and discharging operations using reversible endothermic and exothermic reactions. This material is commonly used because of its low cost, non-toxicity, and thermochemical stability. We have investigated the potential use of the CaCl2/H2O reversible reaction. To achieve practical application of such a system, a higher volumetric power density and longer-term durability are required. Few studies have attempted to quantify the long-term durability of heat input/output performance for assessing practical application. In this study, we studied a bench scale reactor using halogenated alkaline such as CaCl2/H2O reaction system over 1000 repetitions to quantify the long-term durability of heat input/output performance. We used a reagent anhydrous CaCl2 powder with the diameter of 125-250 μm. The experimental setup consists of an evaporator, a condenser, and a reactor. Each component was connected to a thermostat bath as a heat source. A heat exchanger for reactor had 1.1 L in whole volume capacity and measured 250x200x20 mm. The pitch of the fluid flow path was 8 mm, and the pitch of the corrugated fin was 1 mm. The reactor was filled with 530 g of the anhydrous CaCl2 particles. From the results for CaCl2 anhydrate/dehydrate reaction system for the condition of 155°C in reactor temperature, 97°C in evaporator temperature and 30°C in condenser temperature. Discharging or charging reaction almost finished within 1200 seconds for both reaction systems. The heat discharging rate for anhydrate/dihydrate system was twice higher than that for another system due to their original reaction heat. The amount of heat discharged within 1200 seconds were 1.03 MWh/m3-HEX for (1->2), 1.75 MWh/m3-HEX for (0->2), respectively. Those performances were maintained for long repetitive operation over 1000 times.