Utilization of Low Temperature Waste Heat for Cold TES

Abstract

This paper presents an advanced energy cogeneration system that utilizes low temperature waste heat in the range of 60°C to 95°C to produce cold thermal energy storage (TES). Since there is usually a temporal variance between the availability of low temperature waste heat and demand for commercial building air conditioning, a cold TES system is incorporated into this advance energy system. The proposed TES system uses a lithium bromide/water solution both as a refrigerant and as a cold thermal storage material. The cold storage material can be stored at ambient temperature without thermal insulation for an indefinite period of time without losing its charge, making it an ideal system for utilizing peaking system’s low temperature waste heat or to utilize low temperature waste heat during nocturnal operation of continuous generation systems at a time when there are usually low or minimal air conditioning requirements. The heat pump and waste heat is used to recover the thermal storage by reprocessing the stored lithium bromide weak solution to a higher concentration.