Vacuum enclosures for solar thermal panels Part 2: Transient testing with an uncooled absorber plate

Farid Arya, Trevor Hyde, Paul Henshall, Phillip Eames, Stan Shire, Roger Moss

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Creating a vacuum (<1 Pa) around a solar absorber in a flat plate solar thermal collector can increase efficiency by minimising gaseous conduction and convection between the absorber plate and the glass cover. High performance and architecturally attractive flat plate solar thermal collectors are appealing to building owners and designers for supplying clean and renewable energy cost effectively produced via the façade of the building. This two part paper describes the construction techniques and thermal performance of two vacuum enclosures, fabricated at Ulster University, as prototype components for evacuated flat plate solar collectors. The enclosures were tested at three conditions: 0.0033 Pa, 17 Pa and atmospheric pressure. The first enclosure consisted of two glass panes, sealed to an edge spacer and separated by an array of support pillars on a regular square grid to form a narrow evacuated space. The second enclosure, incorporated an uncooled copper plate to represent a solar thermal absorber. Part 1 of this paper has described the fabrication techniques and compared results from hot-box calorimeter and IR thermography testing of the first enclosure with numerical and analytical predictions. Part 2 describes solar simulator testing of the second enclosure which incorporated an uncooled copper plate. Testing under a solar simulator showed a higher stagnation temperature in the high vacuum test (0.0033 Pa) in comparison with the low vacuum (17 Pa) and atmospheric pressure tests. Curve fitting of a heat transfer model to the transient response data demonstrated that radiation and gas conduction were close to predictions. Simulated results were in close agreement with both the transient response and the steady-state asymptotic plate temperatures.
LanguageEnglish
Pages1224-1236
Number of pages13
JournalSolar Energy
Volume174
DOIs
Publication statusPublished - 9 Nov 2018

Fingerprint

Enclosures
Vacuum
Testing
Transient analysis
Atmospheric pressure
Copper
Simulators
Solar absorbers
Glass
Facades
Solar collectors
Curve fitting
Calorimeters
Hot Temperature
Gases
Heat transfer
Radiation
Fabrication
Temperature
Costs

Keywords

  • Solar absorber
  • Evacuated flat plate solar collector
  • Transient heat transfer

Cite this

Arya, Farid ; Hyde, Trevor ; Henshall, Paul ; Eames, Phillip ; Shire, Stan ; Moss, Roger. / Vacuum enclosures for solar thermal panels Part 2: Transient testing with an uncooled absorber plate. 2018 ; Vol. 174. pp. 1224-1236.
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Vacuum enclosures for solar thermal panels Part 2: Transient testing with an uncooled absorber plate. / Arya, Farid; Hyde, Trevor; Henshall, Paul; Eames, Phillip; Shire, Stan; Moss, Roger.

Vol. 174, 09.11.2018, p. 1224-1236.

Research output: Contribution to journalArticle

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AU - Hyde, Trevor

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