TECHNICAL AND ECONOMIC ASSESSMENT OF A NATURAL GAS-POWERED ENGINE-DRIVEN CHILLER SYSTEM

摘要

A considerable share of the electrical energy consumption is due to the air conditioning of buildings. Those consumers operating under differentiated electricity tariffs incur high operating costs, and it is worth of mentioning that it is not always possible to turn off the air conditioning systems during the periods of high tariffs, the so called peak hours. An interesting way of going around this situation is the use of thermal storage systems, where ice or cold water is produced and stored during off-peak periods, when the tariffs are lower. Another way is the use of natural gas fired chillers driven by reciprocating internal combustion engines, since the fuel price is not time dependent. In this work, an assessment of the technical and economical feasibility of the air conditioning systems operating under the Brazilian climate is carried out. Four types of systems are considered, namely conventional electric chillers, taken as reference; conventional electric chillers with thermal storage; turn key package, internal combustion engine plus chiller; and another turn key package, internal combustion engine plus chiller, with thermal storage. Financial parameters, such as internal rate of return (IRR) and the simple payback time, is determined for each system and compared with the reference case, for a given thermal load. Moreover, performance parameters, like fuel consumption, electricity demand and other important figures for the correct technical and economic analysis is presented and discussed.