Case of Study: Off-Design Performance Simulation of a Combined Cycle Taking Account Environmental Conditions in Peru

Authors

Bravo, Héctor J.

Adriazola, Pascual H.

Robles, Gregorio E.

Abstract

The demand for electricity in the country and the world has increased consistently in recent years. Electricity from thermoelectric plants is a viable option that allows diversifying the electricity market and using fossil fuels such as natural gas. The influence of weather conditions on the performance of any machine can mean its viability or infeasibility from a technical and economic point of view. Combined cycle power generation plants are no exception to this fact, but rather their great physical magnitude as machines make them more vulnerable to climatic variables. Environmental conditions such as air temperature and atmospheric pressure significantly influence the performance of a thermoelectric plant, this thesis studies the effect that these climatic variables have on combined cycle comprising a Brayton cycle fed with natural gas and a Rankine cycle of three levels of pressure. Considering the local atmospheric pressure and ambient temperature in La Joya and Majes (located in the department of Arequipa) 8760 off design simulations for each hour of the year in both locations were performed and subsequently the results were compared. Having the same thermoelectric plant installed, the results show that the energy generated in the life of the plant is greater in La Joya than in Majes by 6.64% and that translates into an average annual electricity cost of 6.59% more in Majes than in La Joya, while the efficiency of the plant is 0.2414% higher in La Joya than in Majes. The model also determines the behavior of the plant in certain periods of the year, being the winter and autumn when the performance of the plant increases while in summer and spring periods performance is reduced. While early morning and evening hours are more productive for the plant than daylight hours.