Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger

We analyzed the potential of thermoelectrics for electricity generation in a combined heat and power (CHP) waste heat recovery system. The state-of-the-art organic Rankine cycle CHP system provides hot water and space heating while electricity is also generated with an efficiency of up to 12% at the...

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Autores principales:	Kazuaki Yazawa, Ali Shakouri
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	thermoelectric figure of merit analytic model heat exchanger CHP waste heat recovery Technology T
Acceso en línea:	https://doaj.org/article/d3e897ac077043559b6d239466c7ab39
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spelling	oai:doaj.org-article:d3e897ac077043559b6d239466c7ab392021-11-25T17:28:47ZHeat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger10.3390/en142277911996-1073https://doaj.org/article/d3e897ac077043559b6d239466c7ab392021-11-01T00:00:00Zhttps://www.mdpi.com/1996-1073/14/22/7791https://doaj.org/toc/1996-1073We analyzed the potential of thermoelectrics for electricity generation in a combined heat and power (CHP) waste heat recovery system. The state-of-the-art organic Rankine cycle CHP system provides hot water and space heating while electricity is also generated with an efficiency of up to 12% at the MW scale. Thermoelectrics, in contrast, will serve smaller and distributed systems. Considering the limited heat flux from the waste heat source, we investigated a counterflow heat exchanger with an integrated thermoelectric module for maximum power, high efficiency, or low cost. Irreversible thermal resistances connected to the thermoelectric legs determine the energy conversion performance. The exit temperatures of fluids through the heat exchanger are important for the system efficiency to match the applications. Based on the analytic model for the thermoelectric integrated subsystem, the design for maximum power output with a given heat flux requires thermoelectric legs 40–70% longer than the case of fixed temperature reservoir boundary conditions. With existing thermoelectric materials, 300–400 W/m<sup>2</sup> electrical energy can be generated at a material cost of $3–4 per watt. The prospects of improvements in thermoelectric materials were also studied. While the combined system efficiency is nearly 100%, the balance between the hot and cold flow rates needs to be adjusted for the heat recovery applications.Kazuaki YazawaAli ShakouriMDPI AGarticlethermoelectricfigure of meritanalytic modelheat exchangerCHPwaste heat recoveryTechnologyTENEnergies, Vol 14, Iss 7791, p 7791 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	thermoelectric figure of merit analytic model heat exchanger CHP waste heat recovery Technology T
spellingShingle	thermoelectric figure of merit analytic model heat exchanger CHP waste heat recovery Technology T Kazuaki Yazawa Ali Shakouri Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger
description	We analyzed the potential of thermoelectrics for electricity generation in a combined heat and power (CHP) waste heat recovery system. The state-of-the-art organic Rankine cycle CHP system provides hot water and space heating while electricity is also generated with an efficiency of up to 12% at the MW scale. Thermoelectrics, in contrast, will serve smaller and distributed systems. Considering the limited heat flux from the waste heat source, we investigated a counterflow heat exchanger with an integrated thermoelectric module for maximum power, high efficiency, or low cost. Irreversible thermal resistances connected to the thermoelectric legs determine the energy conversion performance. The exit temperatures of fluids through the heat exchanger are important for the system efficiency to match the applications. Based on the analytic model for the thermoelectric integrated subsystem, the design for maximum power output with a given heat flux requires thermoelectric legs 40–70% longer than the case of fixed temperature reservoir boundary conditions. With existing thermoelectric materials, 300–400 W/m<sup>2</sup> electrical energy can be generated at a material cost of $3–4 per watt. The prospects of improvements in thermoelectric materials were also studied. While the combined system efficiency is nearly 100%, the balance between the hot and cold flow rates needs to be adjusted for the heat recovery applications.
format	article
author	Kazuaki Yazawa Ali Shakouri
author_facet	Kazuaki Yazawa Ali Shakouri
author_sort	Kazuaki Yazawa
title	Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger
title_short	Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger
title_full	Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger
title_fullStr	Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger
title_full_unstemmed	Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger
title_sort	heat flux based optimization of combined heat and power thermoelectric heat exchanger
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/d3e897ac077043559b6d239466c7ab39
work_keys_str_mv	AT kazuakiyazawa heatfluxbasedoptimizationofcombinedheatandpowerthermoelectricheatexchanger AT alishakouri heatfluxbasedoptimizationofcombinedheatandpowerthermoelectricheatexchanger
_version_	1718412314244284416

Heat Flux Based Optimization of Combined Heat and Power Thermoelectric Heat Exchanger

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