Convective heat transfer in a thermal chimney for freshwater production in geothermal total flow systems

Li, W., Yu, G. and Yu, Z. (2023) Convective heat transfer in a thermal chimney for freshwater production in geothermal total flow systems. Applied Thermal Engineering, 230(Part A), 120848. (doi: 10.1016/j.applthermaleng.2023.120848)

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Abstract

The convective heat transfer of air in a laboratory-scale thermal chimney with rectangular cross-section of constant area and two row electrical heaters simulating two heat exchangers was studied experimentally and numerically at 60–200 ℃ nominal temperatures of the top row heaters, 100 ℃ of the low row heaters and 20 ℃ ambient temperature to verify our design concept on freshwater production in geothermal total flow systems. Computational fluid dynamics simulations of air convective heat transfer were performed in ANSYS 2019R CFX based on the three-dimensional, steady Reynolds-averaged Navier-Stokes equations, Boussinesq buoyancy model, k-w turbulence model, and energy equation. The thermal radiation between heater surfaces and chimney walls was considered. The overall thermal and heat transfer characteristics, temperature and flow fields in the chimney were obtained. Effects of boundary condition of heater surface and thermal radiation between two row heaters on heat transfer were discussed. The thermal characteristics of the chimney with two row heaters are better than that with single row heaters. The predicted thermal power and convective Nusselt number agree with the experimental data, and the convective Nusselt number of the low row heaters is enhanced by (11.6–29.8) % compared with the single row heaters. The optimal operating nominal temperature of top row heaters should be higher than 140 ℃, and the optimal centre-to-centre row gap ratio is 5. Multiple jets in the gaps among the heaters and temperature jump crossing each row were observed. The maximum velocity and temperature jump rise with increasing heater nominal temperature.

Item Type:Articles
Additional Information:Zhibin Yu and Wenguang Li would like to acknowledge the financial support provided by EPSRC (EP/T022701/1, EP/V042033/1, EP/P028829/1, EP/N020472/1, EP/N005228/1, EP/V030515/1) in the UK.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Li, Dr Wenguang and Yu, Dr Guopeng and Yu, Professor Zhibin
Authors: Li, W., Yu, G., and Yu, Z.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Applied Thermal Engineering
Publisher:Elsevier
ISSN:1359-4311
ISSN (Online):1873-5606
Published Online:24 May 2023
Copyright Holders:Copyright © 2023 The Authors
First Published:First published in Applied Thermal Engineering 230(Part A): 120848
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
312686Flexible Air Source Heat pump for domestic heating decarbonisation (FASHION)Zhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/V042033/1S&PS - Urban Studies
300663Geothermally Sourced Power and Freshwater Generation for Eastern AfricaZhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/P028829/1ENG - Systems Power & Energy
172394Thermally Driven Heat Pump Based on an Integrated Thermodynamic Cycle for Low Carbon Domestic Heating (Therma-Pump)Zhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/N020472/1ENG - Systems Power & Energy
171763Dynamic Organic Rankine Cycle for Recovering Industrial Waste HeatZhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/N005228/1ENG - Systems Power & Energy
309846Decentralised water technologiesWilliam SloanEngineering and Physical Sciences Research Council (EPSRC)EP/V030515/1ENG - Infrastructure & Environment