Experimental investigation on power generation with low grade waste heat and CO<inf>2</inf>transcritical power cycle

Abstract

In this study, a small-scale test rig of CO 2 transcritical power cycle (T-CO 2 ) system driven by low-grade heat has been developed and investigated experimentally. The test rig consists of a number of essential components including a CO 2 turboexpander with high speed generator, finned-tube air cooled condenser, liquid receiver, CO 2 liquid pump and CO 2 gas generator. The CO 2 is heated in the plate-type gas generator by hot thermal oil flow which is circulated and heated by exhaust flue gases from an 80kW e microturbine CHP unit. The test rig has been fully commissioned, instrumented, controlled and is ready to operate experiment as required. Subsequently, at constant heat sink (ambient) and heat source (thermal oil) temperatures, a series of experiments have been carried out to examine the effects of various important parameters on the T-CO 2 system performance. These include thermal oil flow rate and CO 2 mass flow rate etc. Preliminary experimental results show that the CO 2 TPC is applicable for the low temperature heat sources to generate power although further efficiency improvements are needed. In addition, the experimental outcomes can instruct future optimal system design and controls.