In the quest for a better use of energy resources, energy integration and
cogeneration strategies have been employed in the industrial and commercial
sectors with considerable benefits realized. However, the residential sector
remains underexplored. An optimization procedure should be carried out
whenever there is a need to ensure or verify the economic viability of an
energy system. This study uses Mixed Integer Linear Programming to optimize
the energy supply to a residential building, with 20 floors and 40
apartments, located in the city of Jo?o Pessoa (Northeast Brazil). The
equipment available includes gas engines, electric and natural gas boilers,
heat exchangers, cooling towers, and absorption and mechanical chillers. The
optimization establishes the optimal system configuration and operational
strategy (operation throughout the year). Economic, technical, and legal
aspects were considered in the minimization of the total annual costs
associated with the building?s energy supply. The energy demands were
calculated on an hourly basis, throughout one year, by the EnergyPlus
software and corresponded to hot water (83 MWh/year), electricity (171
MWh/year) and cooling (242 MWh/year) demands. The optimal system was
entirely reliant on the electric grid to meet the electricity demand
directly and to satisfy heating and cooling demands by means of an electric
hot water boiler and a mechanical chiller. The optimal solution is tested by
varying, within reasonable limits, selected parameters: natural gas and
electricity tariffs, the behavior of residents, amortization factor and
relationship between the tariffs of electricity and natural gas.