Experimental Investigation of a Micro-CHP Unit Driven by Natural Gas for Residential Buildings

peer reviewedIn this paper, an experimental performance analysis of a natural gas-driven micro-CHP unit is conducted. This system shows a global nominal heating output of 30.8 kW and is composed of a proton exchange membrane fuel cell (PEMFC), an integrated gas condensing boiler, and a storage tank. The PEMFC has a nominal thermal output of 1.1 kW and 750 W of electrical output. This unit is intended for residential applications to supply the related demands of space heating (SH) and domestic hot water (DHW) while producing electricity during operation. Tests are carried out in the laboratory to characterize the behavior of the global system and its components under different demand requirements. To do so, an emulator of SH and DHW is installed and measures of gas consumption, heat production, and electricity consumption/generation are collected. A test campaign based on the requirements of the EN 50465 is proposed and performed, where the base requirements are extended to a wider range of depart temperatures for SH and DHW; also, the effect of the imposed load over the system global performance is studied. After, both boiler and fuel cell are tested separately to characterize their contribution to the global system. The results show that the overall efficiency is mainly composed of the thermal output, being the electrical part a small fraction of the total, and with trends indicating that the lower the water outlet temperature, the higher the efficiency; the same trend is observed with respect to the heat demand since the lower this is, the higher the efficiency. The results obtained for the boiler efficiency are close to those announced by the manufacturer, but for the fuel cell, the obtained results are varied due to the complexity of the system.7. Affordable and clean energy11. Sustainable cities and communities13. Climate actio