Exploration of a simple, low cost, micro gas turbine recuperator solution for a domestic combined heat and power unit

Clay, A. and Tansley, G.D. (2011). Exploration of a simple, low cost, micro gas turbine recuperator solution for a domestic combined heat and power unit. Applied Thermal Engineering, 31 (14-15), pp. 2676-2684.

Abstract

For micro gas turbines (MGT) of around 1 kW or less, a commercially suitable recuperator must be used to produce a thermal efficiency suitable for use in UK Domestic Combined Heat and Power (DCHP). This paper uses computational fluid dynamics (CFD) to investigate a recuperator design based on a helically coiled pipe-in-pipe heat exchanger which utilises industry standard stock materials and manufacturing techniques. A suitable mesh strategy was established by geometrically modelling separate boundary layer volumes to satisfy y + near wall conditions. A higher mesh density was then used to resolve the core flow. A coiled pipe-in-pipe recuperator solution for a 1 kW MGT DCHP unit was established within the volume envelope suitable for a domestic wall-hung boiler. Using a low MGT pressure ratio (necessitated by using a turbocharger oil cooled journal bearing platform) meant unit size was larger than anticipated. Raising MGT pressure ratio from 2.15 to 2.5 could significantly reduce recuperator volume. Dimensional reasoning confirmed the existence of optimum pipe diameter combinations for minimum pressure drop. Maximum heat exchanger effectiveness was achieved using an optimum or minimum pressure drop pipe combination with large pipe length as opposed to a large pressure drop pipe combination with shorter pipe length.

Publication DOI: https://doi.org/10.1016/j.applthermaleng.2011.04.037
Divisions: Engineering & Applied Sciences > Mechanical engineering & design
Engineering & Applied Sciences > Engineering systems & management
Uncontrolled Keywords: CFD,Coiled,DCHP,domestic Combined Heat and Power,heat exchanger,helically,MGT,micro combined heat and power,micro gas turbine,micro recuperator,pipe-in-pipe,Energy Engineering and Power Technology,Industrial and Manufacturing Engineering
Full Text Link: https://hal.arc ... 781355/document
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2011-10
Authors: Clay, A.
Tansley, G.D.

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