Performance improvement of a solar air heater by covering the absorber plate with a thin porous material

Document identifier: oai:DiVA.org:ltu-76958
Access full text here:10.1016/j.energy.2019.116437
Keyword: Engineering and Technology, Mechanical Engineering, Fluid Mechanics and Acoustics, Teknik och teknologier, Maskinteknik, Strömningsmekanik och akustik, Solar air heater, Porous media, Turbulence, Nusselt number, Thermo-hydraulic performance, Strömningslära, Fluid Mechanics
Publication year: 2020
Relevant Sustainable Development Goals (SDGs):

The SDG label(s) above have been assigned by OSDG.ai

Abstract:

The effect of covering the absorber plate of a solar air heater with a thin porous media is investigated in the present study. Simulations are carried out for turbulent flow and heat transfer in the solar heater and within the porous layer. The effects of different parameters such as Reynolds number, Darcy number and solid to fluid thermal conductivity ratio on the thermal and thermo-hydraulic performances of a solar air heater are studied. It is observed that the implementation of a thin porous layer over the absorber plate significantly increases the thermal and thermo-hydraulic performances of the solar air heater. The maximum increase in the thermal and thermo-hydraulic performances is more than 5 times of those obtained in a solar heater without porous medium. Meanwhile, the maximum increase in the frictions factor of the porous solar heater is 2 times of that in a solar heater without porous media at the maximum Reynolds number studied. The proposed configuration also reduces the risk of hot spots since no entrapped eddies are formed over the absorber plate. It is shown that the turbulence produced at the porous-fluid interface penetrates into the thin porous layer and enhances the heat transfer from the absorber plate. The results also reveal that the conduction heat transfer within the porous layer highly affects the thermal and thermo-hydraulic performances of the solar heater.

Authors

Nima Fallahjoybari

Luleå tekniska universitet; Strömningslära och experimentell mekanik
Other publications >>

Staffan Lundström

Luleå tekniska universitet; Strömningslära och experimentell mekanik
Other publications >>

Record metadata

Click to view metadata

	
    header: 
        identifier: oai:DiVA.org:ltu-76958
        datestamp: 2021-04-19T12:44:48Z
        setSpec: SwePub-ltu
    metadata: 
        mods: 
            @attributes: 
                version: 3.7
            recordInfo: 
                recordContentSource: ltu
                recordCreationDate: 2019-11-29
            identifier: 
                http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76958
                10.1016/j.energy.2019.116437
                2-s2.0-85075359673
            titleInfo: 
                @attributes: 
                    lang: eng
                title: Performance improvement of a solar air heater by covering the absorber plate with a thin porous material
            abstract: 
The effect of covering the absorber plate of a solar air heater with a thin porous media is investigated in the present study. Simulations are carried out for turbulent flow and heat transfer in the solar heater and within the porous layer. The effects of different parameters such as Reynolds number Darcy number and solid to fluid thermal conductivity ratio on the thermal and thermo-hydraulic performances of a solar air heater are studied. It is observed that the implementation of a thin porous layer over the absorber plate significantly increases the thermal and thermo-hydraulic performances of the solar air heater. The maximum increase in the thermal and thermo-hydraulic performances is more than 5 times of those obtained in a solar heater without porous medium. Meanwhile the maximum increase in the frictions factor of the porous solar heater is 2 times of that in a solar heater without porous media at the maximum Reynolds number studied. The proposed configuration also reduces the risk of hot spots since no entrapped eddies are formed over the absorber plate. It is shown that the turbulence produced at the porous-fluid interface penetrates into the thin porous layer and enhances the heat transfer from the absorber plate. The results also reveal that the conduction heat transfer within the porous layer highly affects the thermal and thermo-hydraulic performances of the solar heater.

            subject: 
                    @attributes: 
                        lang: eng
                        authority: uka.se
                    topic: 
                        Engineering and Technology
                        Mechanical Engineering
                        Fluid Mechanics and Acoustics
                    @attributes: 
                        lang: swe
                        authority: uka.se
                    topic: 
                        Teknik och teknologier
                        Maskinteknik
                        Strömningsmekanik och akustik
                    @attributes: 
                        lang: eng
                    topic: Solar air heater
                    @attributes: 
                        lang: eng
                    topic: Porous media
                    @attributes: 
                        lang: eng
                    topic: Turbulence
                    @attributes: 
                        lang: eng
                    topic: Nusselt number
                    @attributes: 
                        lang: eng
                    topic: Thermo-hydraulic performance
                    @attributes: 
                        lang: swe
                        authority: ltu
                    topic: Strömningslära
                    genre: Research subject
                    @attributes: 
                        lang: eng
                        authority: ltu
                    topic: Fluid Mechanics
                    genre: Research subject
            language: 
                languageTerm: eng
            genre: 
                publication/journal-article
                ref
            note: 
                Published
                2
                
Validerad;2020;Nivå 2;2020-01-10 (johcin)

            name: 
                    @attributes: 
                        type: personal
                        authority: ltu
                    namePart: 
                        Fallahjoybari
                        Nima
                    role: 
                        roleTerm: aut
                    affiliation: 
                        Luleå tekniska universitet
                        Strömningslära och experimentell mekanik
                    nameIdentifier: 
                        nimfal
                        0000-0002-4627-2760
                    @attributes: 
                        type: personal
                        authority: ltu
                    namePart: 
                        Lundström
                        Staffan
                    role: 
                        roleTerm: aut
                    affiliation: 
                        Luleå tekniska universitet
                        Strömningslära och experimentell mekanik
                    nameIdentifier: 
                        stlu
                        0000-0002-1033-0244
            originInfo: 
                dateIssued: 2020
                publisher: Elsevier
            relatedItem: 
                @attributes: 
                    type: host
                titleInfo: 
                    title: Energy
                identifier: 
                    0360-5442
                    1873-6785
                part: 
                    detail: 
                            @attributes: 
                                type: volume
                            number: 190
                            @attributes: 
                                type: artNo
                            number: 116437
            physicalDescription: 
                form: print
            typeOfResource: text