CONCEPT AND OPERATION OF AN INNOVATIVE TWO-STAGE ABSORPTION CHILLER FOR EFFICIENT AND FLEXIBLE TRIGENERATION

摘要

In conventional Tri-Generation systems, single-stage absorption chillers are coupled to cogeneration engines through a single hot water loop at temperatures below 100°C. In this configuration, the heat from the co-generator's exhaust gas at temperatures of about 400-500°C is transferred to the hot water loop, implying a significant loss of exergy. A substantial increase in system performance can be achieved by a stepwise utilization of the exhaust gas enthalpy in a Double-Effect and a Single-Effect cycle. In order to establish highly efficient Tri-Generation systems with optimum adaptation of the aggregates - i.e. motor engine and absorption chiller - and in order to give maximum flexibility an innovative system concept has been developed, allowing for an increase of the cooling capacity by about 30%. The new coupling scheme is based on a standard direct-fired Double-Effect chiller and introduces only minor design changes, like adaptation of the thermal layout of the exhaust gas driven regenerator heat exchanger of the chiller. No additional low temperature regenerators are required. In case of simultaneous heating and cooling the system supports a continuous switchover from maximum cooling to maximum heating capacity. In this mode up to 80% of the driving heat for cold production can be recovered as useful heat at temperatures up to 100°C. A description of the coupling scheme together with a discussion of energetic and operational characteristics of the concept is presented. A full-scale demonstration project is under preparation.