O. Le Corre

Fuel Savings and CO2 Emissions for Tri-generation Systems

Abstract The paper presents a method for analysing tri-generation systems from the point of view of fuel savings and environmental impact. The authors have focused on the solution of tri-generation plants based on gas turbine or internal combustion engine with an absorption chilling machine. Criteria that characterise the fuel savings and CO2 emissions of tri-generation have been defined. An analysis has been performed for the case of tri-generation with an absorption chilling machine. The mathematical dependence of fuel savings and CO2 emissions on different technical criteria has been analysed. For a certain case there has been plotted the variation of fuel savings as a dependence of technical criteria. The graphs highlight the range of technical criteria with better fuel savings for tri-generation than for separate production. There has been established the order of influence of different technical criteria on fuel savings.

Thermodynamic analysis of tri-generation with absorption chilling machine

The paper presents a method for analysing tri-generation systems. The authors have focused on solutions of tri-generation plants based on gas turbine or internal combustion engine with absorption chilling machine. Several technical criteria have been defined. A thermodynamic analysis has been performed for the case of tri-generation with an absorption chilling machine. From the thermodynamic point of view there have been established the limits for the best energetic performance of tri-generation. The dependence of different technical criteria on each other has also been analysed. A certain case of a tri-generation plant has been analysed using this method. The dependence of the energetic performance of tri-generation on different technical criteria has also been studied.

Knock rating of gaseous fuels in a single cylinder spark ignition engine

Abstract This paper presents the determination of knock rating of gaseous fuels in a single cylinder engine. The first part of the work deals with an application of a standard method for the knock rating of gaseous fuels. The Service Methane Number (SMN) is compared with the standard Methane Number (MN) calculated from the standard AVL software METHANE (which corresponds to the MN measured on a Cooperative Fuel Research engine). Then, in the second part, the ‘mechanical’ resistance to knock of our engine is highlighted by means of the Methane Number Requirement (MNR). A single cylinder LISTER PETTER engine was modified to run as a spark ignition engine with a fixed compression ratio and an adjustable spark advance. Effects of engine settings on the MNR are deduced from experimental data and compared extensively with previous studies. Using the above, it is then possible to adapt the engine settings for optimal knock control and performances. The error on the SMN and MNR stands beneath ±2 MN units over the gases and engine settings considered.

TDC Determination in IC Engines Based on the Thermodynamic Analysis of the Temperature-Entropy Diagram

A thermodynamic methodology of TDC determination in IC engines based on a motoring pressure-time diagram is presented. This method consists in entropy calculation and temperature- entropy diagram analysis. When the TDC position is well calibrated, compression and expansion strokes under motoring conditions are symmetrical with respect to the peak temperature in the (T,S) diagram. Moreover, in case of error on the TDC position, a loop appears which has no thermodynamic significance. Hence an easy methodology has been conceived to obtain the actual position of TDC. This methodology is applied to motoring measurements in order to present its performance, which are compared to usual methods.

Thermal efficiency and environmental performances of a biogas-diesel stationary engine

Abstract Municipal and agricultural waste, and sludge from wastewater treatment represent a large source of pollution. Gaseous fuels can be produced from waste decomposition and then used to run internal combustion engines for power and heat generation. The present paper focuses on thermal efficiency and environmental performances of dual‐fuel engines fuelled with biogas. Experiments have been carried out on a Lister‐Petter single cylinder diesel engine, modified for dual‐fuel operation. Natural gas was first used as the primary fuel. An empirical correlation was determined to predict the engine load for a given mass flow rate for the pilot fuel (diesel) and for the primary fuel (natural gas). That correlation has then been tested for three synthesized biogas compositions. Computations were performed and the error was estimated to be less than 10%. Additionally, NOx and CO2 contents were measured from exhaust gases. Based on exhausts gas temperature, the activation energy and the pre‐exponential factor of an Arrhenius law were then proposed, resulting in a simpler mean to predict NOx.

Compression Ratio and TDC Calibrations Using Temperature - Entropy Diagram

An extension of a thermodynamic methodology of TDC determination in IC engines is presented. The effect of an error on the TDC position coupled with an error on the compression ratio is analyzed in the temperatureentropy diagram. When the TDC position and the compression ratio are well calibrated, compression and expansion strokes under motoring conditions are symmetrical with respect to the peak temperature in the (T,S) diagram. Moreover, in case of an error on the TDC position, a loop appears, which has no thermodynamic significance. In the same way, in case of a compression ratio error the (T,S) diagram leans. Hence, an easy methodology has been conceived to obtain the right position of TDC and eventually to correct the compression ratio. This methodology is applied on motoring measurements to assess its performance.