Modeling and simulation of cogeneration systems for buildings on a university campus in Northeast Brazil – A case study

Abstract

In countries with tropical climates there is a great need for air-conditioning in buildings. This is due to the high temperatures and high humidity in the tropics and sub-tropical regions such as Northeast Brazil. Overall, electricity bills show that an excessive amount of money is spent on achieving thermal comfort using regular air-conditioning systems to remove heat from buildings. The electricity consumed by such systems can represent about 50% of the total electricity bill. This paper proposes using a cogeneration system in the rectorate building of a university campus. A cogeneration system comprises a reciprocating engine as the prime mover, a back-up boiler, an accumulation tank and a single-effect absorption chiller to remove excess heat. The main advantage of using this kind of system is that increasing the production temperature of cold water improves the overall efficiency of the system as the residual heat is at a lower temperature. This solution is applied to the rectorate of the Federal University of Paraíba (UFPB) in João Pessoa, Northeast Brazil, where the demand for cool temperatures is intense and the consumption of energy is extremely high since the average annual relative humidity and the dry bulb temperature are about 75% and 27 °C, respectively.