Experimental results of the influence of environmental conditions on the performance of a small-size ICE-based CHP

Abstract

The diffusion of distributed sources for the electricity generation is growing worldwide in reason of the inherent advantages they bring to the power grid and to the environment: the relief in the grid congestion and the reduced carbon footprint, in conjunction with the increased flexibility, bring great advantages in the total performance of the energy systems. Within this context micro-cogeneration, especially if based on alternative Internal Combustion Engines (ICEs), plays a fundamental role, and the technical and experimental evidence shows the benefit in terms of energy efficiency and Green-House Gases (GHGs) reduction it can bring, also including their affordability and reliability. When dealing with their performance, one of the aspects that is quite often neglected is the influence that the varied environmental conditions play in the performance of the system; if this issue can be considered as one of the minor affecting the Combined Heat and Power (CHP) system output for the small sizes, its consequence can remarkably modify the profitability on the investment compared to the initial plan. In the present analysis, the experimental data gathered from the monitoring of a Yanmar micro-CHP installed in a Small-Medium Enterprise (SME) in central Italy are extensively analyzed, particularly focusing the attention on the variation of the efficiency and on the gas consumption in different periods of the year. The micro-cogeneration system data are gathered for more than one year, allowing a precise characterization of the system and, at the same time, the analysis of the aging of the installed piece of equipment. A comparison in terms of environmental and economic performance of the CHP between real data and catalogue data will be carried out as well in order to quantify the total influence of the environmental off-design conditions.