Small Scale Polygeneration System for Hotels in Costa Rica

Abstract: In a world where energy consumption increases every year and the current system harms the environment, new technologies are necessary to cope with such intensive energy demands worldwide. In such an era, polygeneration systems are an innovative and sustainable solution for that problem. Polygeneration systems can simultaneously produce electricity, heating, cooling, hot water, potable water, and other services in smaller, more flexible, and more efficient ways. Small-scale polygeneration systems can also help with the decentralization of energy generation and with promoting the use of more renewable energy sources in the power generation sector. In this study, a polygeneration system is proposed for an ecohotel in the Guanacaste region of Costa Rica. The ecohotel demand as well as the availability of local renewable energy resources were studied to size the components of the system correctly. The small-scale polygeneration system consists of a biomass gasifier and an internal combustion engine as prime mover, as well as PV panels, batteries, a biomass boiler, an absorption chiller, and a membrane distillation system. The outputs obtained from the system and to be used in the hotel are electricity, cooling, hot water, and potable water. The results obtained were positive from an economic and environmental perspective when compared to the national grid electricity system. The economic savings are of $410,268 per the system lifetime of 25 years, which represents a 27% margin difference. As for the emissions, 14.4 tons of CO2 are saved every year from going into the atmosphere which represents a 38% yearly reduction. The results shown in this study reflect that the polygeneration systems are of great interest in order to shift to a more sustainable and efficient energy system. This study can be replicated by other hotels in Costa Rica taking into consideration the natural resources present in the local surroundings and adjusting the system to those resources available.