Experimental investigation on latent heat thermal energy storage system for stationary C.I. engine exhaust

Highlights: • Thermal energy storage system is integrated with stationary CI engine. • Erythritol is used as phase change material. • Maximum 69.53% charging efficiency is obtained. • Percentage energy saved is 11.33%. - Abstract: Increasing gap between demand and supply of energy has resulted in raised prices of conventional energy sources, and concern for clean environment has led to increase in use of renewable energy and focus on increased energy efficiency. In context of increased energy efficiency, energy storage and waste heat recovery play an important role as these systems improve overall efficiency of systems. In this study, a latent heat thermal energy storage system (LHTESS) for stationary C.I. engine exhaust heat was developed and integrated with engine. A shell and tube type heat exchanger having 346 mm diameter and 420 mm height with 45 numbers of tubes with 18 mm diameter was developed to store thermal energy, in which Erythritol (C₄H₁₀O₄) was used as a phase change material. The engine performance and the thermal energy storage system performance parameters such as amount of heat stored, and charging efficiency were evaluated. Slight decrease in the engine performance was observed when latent heat thermal energy storage system was integrated to engine but amount of energy which could be recovered was significant. At a load of 4.4 kW the maximum charging efficiency, recovery efficiency and percentage energy saved was 69.53%, 38% and 11.33% respectively.