Technical and economic modeling of a trigeneration system with EF7 engine as a prime mover

Abstract

In this paper, a comprehensive technical and economic modeling of a trigeneraion system based on a gas engine named EF7 is presented. The innovation is presenting a differential model with high accuracy which considers the effects of spark timing in half-load and full-load modes on the system technical performance, including specific fuel consumption, and the economic performance of the system, including fuel cost savings, investment payback period, net present value and internal rate of return.From economic viewpoint, at half-load condition and optimal spark timing (18° CA BTDC), the system will reach profitability after 8 years. From technical viewpoint, at half-load condition, the spark timing should be more advanced (24° CA BTDC) and the overall specific fuel consumption is 103.24 gr/kWh.But, at full-load mode and optimum ignition timing (18° CA BTDC), the economic performance has improved and with 10% inflation rate, the system can reach profitability after 4 years. Also, after 7 and 10 years, the profit values are $42,300 and $80,500, respectively and internal rate of return values of 22 and 26%, respectively. Also, from technical viewpoint, at full-load condition and optimal spark timing (22° CA BTDC) the minimum amount of overall specific fuel consumption is 110.42 gr/kWh.

Keywords

• CCHP system
• Gas engine
• Spark timing
• Net present value
• Internal rate of return