Comparison Based on Exergetic Analyses of Two Hot Air Engines: A Gamma Type Stirling Engine and an Open Joule Cycle Ericsson Engine

Abstract

Abstract:In this paper, a comparison of exergetic models between two hot air engines (a Gamma type Stirling prototype having a maximum output mechanical power of 500 W and an Ericsson hot air engine with a maximum power of 300 W) is made. Referring to previous energetic analyses, exergetic models are set up in order to quantify the exergy destruction and efficiencies in each type of engine. The repartition of the exergy fluxes in each part of the two engines are determined and represented in Sankey diagrams, using dimensionless exergy fluxes. The results show a similar proportion in both engines of destroyed exergy compared to the exergy flux from the hot source. The compression cylinders generate the highest exergy destruction, whereas the expansion cylinders generate the lowest one. The regenerator of the Stirling engine increases the exergy resource at the inlet of the expansion cylinder, which might be also set up in the Ericsson engine, using a preheater between the exhaust air and the compressed air transferred to the hot heat exchanger. OPEN ACCESSEntropy 2015, 17 7332

4.6 Stirling Engines

“…• According to Hachem et al [113], the proportion of total exergy destruction compared with the exergy flux from the hot source is similar for both engines (respectively 44% and 47% of the exergy flux from the hot source for the Stirling and Ericsson engines). The largest exergy destruction occurs in the compression cylinder, mainly due to generated entropy in the case of the Ericsson engine and due to a similar proportion of generated entropy and of heat loss toward the cold source for the Stirling engine.…”

“…Based on this study, authors proposed an empirical model for predicting the value of an asymmetry of temperature between both regenerator sides' function of operation parameters. • At nearly the same working conditions, the Stirling engine presents higher global performances (specific indicated work, thermodynamic and exergetic efficiencies) compared with the Ericsson engine [113], due to the presence of a regenerator. The gap between these performances (about 24.18% of global exergetic efficiency and 15.53% of global thermodynamic efficiency) might be reduced using a preheater in the Ericsson engine.…”

The effects of different channel geometries in the displacer cylinder, working fluids, and engine speed on the energy and exergy performance characteristics of a β-type Stirling engine with a slider-crank drive mechanism

“…The exergy balance of the control volume in Figure 3 is given in equation (5). 23 Here ( E x dest ) is exergy destruction, ( E x in ) is exergy entering the system, and ( E x out ) is exergy leaving the system. The power acquired from the engine is taken equal to the exergetic power (W) value.…”

Biomass Cogeneration Technologies: A Review

“…It is a reciprocating engine that operates with the open Joules cycle, it is composed of two cylinders (compression cylinder and expansion), a heat exchanger that allows the adjustment of the inlet and valve temperature levels at the inlet and outlet of the cylinders [65] [66]. The working fluid, which is air, enters the compression cylinder at atmospheric pressure and ambient temperature, is compressed and then sent to the heat exchanger, its temper increases and then enters the expansion cylinder where it expands so that it is finally discharged outside the engine [67] (Figure 6).…”