Residential microcogenerators for multifamily houses

Miniaturization of energy conversion devices is an ongoing process which could also be extended to cogeneration systems. Many models of microcogenerators are being commercialized worldwide nowadays. With respect to energy performance, many benefits are expected by these systems, such as the reduction of cycling losses and of transmission and distribution losses due to distributed generation. Furthermore, the reduction of performance with the size of the device must be considered to evaluate the effective reduction of primary energy consumption, greenhouse gas emissions and operating costs. This paper reports the results of an energy, economic and environmental analysis performed on different microcogenerators used to meet energy requirements of a residential building located in Southern Italy. On the basis of thermal and electric load profile of a typical residential user, two configurations have been considered: central and autonomous heating system. Primary energy saving is satisfactory for microcogeneration systems considered, ranging between 16.6 % and 26.4%. A similar results is obtained by environmental parameter with avoided CO₂ emission higher than 24%. The economic analysis does not produce positive results due to high specific investment cost of small size cogeneration units and low operating hours per year. Finally the solution based on centralized heating system provides the best results.