Cogeneration is the process of simultaneously producing and consuming electricity and heat from the same main energy source and within the same facility. It is based on the fact that the production of electricity releases a large quantity of heat that is usually unused. It uses this heat to achieve an overall energy efficiency of up to 85%. For residential scale, current restrictions insist on considering micro-cogeneration, in minimum, as a second source of supplying energy. As part of the energy transition, micro-cogeneration is a technology that could address the growing demand for decentralized generation. The challenge counter the micro-cogeneration technology is to be beneficial for homes with a high heat demand. The micro-CHP systems sized from 0.7 to 5 KW consisted mainly of an electrical component, heat recovery system and a prime mover. The prime mover, which constitutes the first part of a cogeneration plant, producing electricity as main-product and heat as a by-product, is divided into three common categories: Steam turbines, Gas turbines and Fuel cells. The increase in demand for electricity to provide hot water and space heating, pushed the micro-CHP market to head towards PEMFC (Proton Exchange Membrane Fuel Cell). Since, the electrical output of the fuel cell-based micro-CHP systems is more resilience in than conventional engine systems, they are expected to widely expand during the upcoming period.

In this article, a micro-CHP system composed of a 750-W LT-PEMFC, a hydrogen condensing boiler, a domestic hot water tank and a management system, integrated with a renewable source system (Photovoltaic (PV) and Wind turbine) to produce the needed hydrogen, is investigated. In order to validate our system, a bench test was built. The Vitovalor-PT2, a residential CHP system fabricated by Viessmann to cover the electrical, heating and domestic hot water of a single family. The Vitovalor-PT2 works with hydrogen and air. A system where natural gas is transformed into hydrogen thanks to the integrated gas treatment device. The heat induced by the production of electricity will be used for heating and the production of domestic hot water, all the energy is thus used without loss. Vitovalor- PT2 is composed of two main units: the fuel cell module,which consume hydrogen produced by an integrated reformer which convert natural gas to hydrogen, and the peak load module with gas condensing boiler. Plus, an integrated 220-liter stainless steel hot water tank as well as the hydraulics, sensors and controls. The performance of the validated system over a year was evaluated basing on the daily estimated thermal and electrical needs of a 120 m2 typical French house. The system was evaluated by applying different external and internal conditions, in order to prove its capability to withstanding different climate zone and meeting the comfort demanded. Furthermore, the effect of the house surface and insulation rate on the overall system efficiency was investigated. The findings of the dynamic simulation for the city of Caen (491109N - 02132E), shows that the system overall efficiency was 88.45% with an electrical and thermal efficiency of 17.53% and 70.93% respectively. The electrical, thermal and hydrogen coverage rates are 73%, 100% and 47% respectively with 34 installed PV panels.