Cold thermal storage integration in a large industrial refrigeration system

Abstract

Global warming is one of the greatest challenges our society faces today, and researchers strive to find solutions to reduce the emissions of greenhouse gases that accelerate the global warming effect. This paper describes a concept for a large cold thermal energy storage (CTES) system integrated in an industrial NH3/CO2 cascade refrigeration system for a poultry processing plant. The refrigeration system is fully centralized while oil-free CO2 is pumped to the freezing and cooling equipment. The CTES consists of closed tanks that contain stacks of heat exchanger plates with circulating CO2 on the inside and a phase change material (PCM) in the tank. During charging, the CO2 evaporates inside the plates while the PCM changes phase from liquid to solid. The purpose of CTES is to reduce daytime peaks in the energy use, e.g. charging the storage during night and weekends and discharging during times of peak refrigeration demand. The performance of the system is investigated through simulations with Modelica/Dymola.