Abstract
Natural convection is measured in an enclosure that represents an integral collector storage solar system with an immersed heat exchanger. The enclosure has an aspect ratio of 9.3:1 and is inclined 30 deg to the horizontal. Heat transfer coefficients for bundles of 240 tubes are obtained for a range of transient operating modes and pitch-to-diameter ratios of 1.5, 2.4, and 3.3. Results for isothermal and stratified enclosures yield a correlation for the overall Nusselt number, NuD = (2.45±0.03)RaD 0.188, 230 ≤ RaD ≤ 9800. Nusselt numbers are three times larger than those for a similarly configured single-tube and an eight-tube bundle. This increase is attributed to stronger fluid motion within the bundle and greater overall circulation rates in the enclosure.
Original language | English (US) |
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Title of host publication | International Solar Energy Conference |
Pages | 237-246 |
Number of pages | 10 |
DOIs | |
State | Published - 2004 |
Event | 2004 International Solar Energy Conference - Portland, OR, United States Duration: Jul 11 2004 → Jul 14 2004 |
Other
Other | 2004 International Solar Energy Conference |
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Country/Territory | United States |
City | Portland, OR |
Period | 7/11/04 → 7/14/04 |