Performance of micro CHP unit based on SI engine with quantitative-qualitative load control

Abstract

The paper presents data resulting by the preliminary experimental tests performed on a micro CHP (combined heat and power) 7 kWel unit. The engine load has been controlled by throttle position (quantitatively) or/and the value of air excess ratio (qualitatively) QQLC. By this way the engine efficiency can be improved in the range of partial loads by reducing the exergy losses during the inlet stroke. During the tests engine has been powered with LPG fuel. The engine performance together with environmental impact has been studied in this paper. Used method shows that despite the reduction of the load from 5.6 kW to 4.7 kW while burning the lean mixture, the efficiency of electricity generation increased slightly. The efficiency grew by approx. 1.41 percentage point comparing with the re-sults obtained for almost constant load but obtained by burning the lean mixture (λ = 1.3), followed by increased throttling and combus-tion of the stoichiometric mixture.

The tests of micro-CHP prototype with SI engine powered by LPG and natural gas

“…in cooperation with a research team from the Silesian University of Technology as part of a project co-financed from the sources of the Regional Operational Program of the Silesian Voivodeship. A similar study has been conducted previously when using an asynchronous generator and the results were presented in the paper [11].…”