Numerical analysis of secondary heat exchanger designed for CHP units with microturbine

Macháčková, Adéla; Kocich, Radim; Bojko, Marián; Klečková, Zuzana

doi:10.1016/j.ijheatmasstransfer.2014.12.038

Cited by 5 publications

(2 citation statements)

References 28 publications

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“…Rapid developments in engineering, together with the demand for innovative materials featuring specific properties for challenging applications, from transportation [1,2], through power engineering [3][4][5], to biomedicine [6,7], have resulted in the emergence of several paths leading to the fabrication of various metallic materials with exceptional performances and increased longevity. The mechanical properties-ultimate tensile strength (UTS), in particular-of metallic materials are highly influenced by the microstructures, i.e., grain size and morphology [8,9].…”

Section: Introduction 1grain Refinement Mechanismsmentioning

confidence: 99%

Structural Phenomena Introduced by Rotary Swaging: A Review

Kunčická

2024

Materials

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Rotary swaging is an industrially applicable intensive plastic deformation method. Due to its versatility, it is popular, especially in the automotive industry. Similar to the well-known methods of severe plastic deformation (SPD), rotary swaging imparts high shear strain into the swaged materials and thus introduces grain refinement down to a very fine, even ultra-fine, level. However, contrary to SPD methods, one of the primary characteristics of which is that they retain the shapes and dimensions of the processed sample, rotary swaging enables the imparting of required shapes and dimensions of workpieces (besides introducing structure refinement and the consequent enhancement of properties and performance). Therefore, under optimized conditions, swaging can be used to process workpieces of virtually any metallic material with theoretically any required dimensions. The main aim of this review is to present the principle of the rotary swaging method and its undeniable advantages. The focus is primarily on assessing its pros and cons by evaluating the imparted microstructures.

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Section: Introduction 1grain Refinement Mechanismsmentioning

confidence: 99%

Structural Phenomena Introduced by Rotary Swaging: A Review

Kunčická

2024

Materials

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“…The core part of a CHP system is a primary unit, which can be an engine, microturbine or solid oxide fuel cells, which additionally produces waste heat. Heat can be used for the heating purposes or for preparation of the hot utility water [2,6]. Moreover, µ-CHP units with solid oxide fuel (SOFC) demonstrate electrical efficiency exceeding 45% at a power output of single kilowatts [7].…”

Section: Introductionmentioning

confidence: 99%

Modeling the dynamic operation of a small fin plate heat exchanger – parametric analysis

Motyliński

Kupecki

2015

Archives of Thermodynamics

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Given its high efficiency, low emissions and multiple fuelling options, the solid oxide fuel cells (SOFC) offer a promising alternative for stationary power generators, especially while engaged in micro-combined heat and power (µ-CHP) units. Despite the fact that the fuel cells are a key component in such power systems, other auxiliaries of the system can play a critical role and therefore require a significant attention. Since SOFC uses a ceramic material as an electrolyte, the high operating temperature (typically of the order of 700-900• C) is required to achieve sufficient performance. For that reason both the fuel and the oxidant have to be preheated before entering the SOFC stack. Hot gases exiting the fuel cell stack transport substantial amount of energy which has to be partly recovered for preheating streams entering the stack and for heating purposes. Effective thermal integration of the µ-CHP can be achieved only when proper technical measures are used. The ability of efficiently preheating the streams of oxidant and fuel relies on heat exchangers which are present in all possible configurations of power system with solid oxide fuel cells. In this work a compact, fin plate heat exchanger operating in the high temperature regime was under consideration. Dynamic model was proposed for investigation of its performance under the transitional states of the fuel cell system. Heat exchanger was simulated using commercial modeling software. The model includes key geometrical and functional parameters. The working conditions of the power unit with SOFC vary due to the several factors, such as load changes, heating and cooling procedures of the stack and others. These issues affect parameters of the incoming streams to the heat exchanger. The mathematical model of the heat exchanger is based on 1 Corresponding Author. E-mail: konrad.motylinski@ien.com.pl 86 K. Motyliński and J. Kupecki a set of equations which are simultaneously solved in the iterative process. It enables to define conditions in the outlets of both the hot and the cold sides. Additionally, model can be used for simulating the stand-alone heat exchanger or for investigations of a semiadiabatic unit located in the hotbox of the µ-CHP unit.

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