Experimental analysis of small scale polygeneration system based on a natural gas-fired Micro-CHP and a hybrid HVAC system equipped with a desiccant wheel

During the last decade, in the Mediterranean area, during the warm season, there is an increasing demand of cooling energy in domestic and small commercial sectors, generally satisfied by electrically-driven units. This trend has involved an increase of the power generation capacity of electric utilities and a summer peak load of electric energy consumption with the related problem of electric black-out. This problem has been the driving force to an increasing interest in small scale polygeneration systems fuelled by natural gas, especially in the South of Europe. These energy conversion systems are based on a prime mover that can drive in different ways (mechanically, electrically, thermally) electric generators and/or electric heat pump, absorption heat pumps, desiccant wheels, … allowing a wide range of operating conditions to match thermal (heating and cooling) and electric end-user requirements. In particular, in this paper, attention is paid to the description of a test facility, located in Southern Italy, designed and built to carry out experimental analysis on a small scale polygeneration system based on a natural gas-fired Micro- CHP and a hybrid HVAC (Heating, Ventilation and Air Conditioning) system equipped with a desiccant wheel. The MCHP supplies thermal power, recovered by engine cooling and exhaust gas, to the regeneration of the sorption material of the desiccant wheel and electric power for Air Handling Unit, AHU, self consumptions (fans, pumps, …), to drive the electric chiller and finally for the external units (computers, lights…). The hybrid HVAC system can also operate in traditional way, interacting with separate “production” systems (electric grid and gas-fired boiler). In this paper the first experimental results considering different operating modes are reported.