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Performance prediction of solar thermal systems and the use of monolithic silica aerogel to improve collector efficiency

Abstract

This thesis is devoted to a study of active solar thermal systems, and focuses on analysis and design tools. The main part of this work is concerned with development of algorithms for modeling flat-plate collectors that use monolithic silica aerogel (MSA) as part of cover glazing. This study of MSA collectors also includes evaluation of the performance of the collector component, and simulation studies of solar systems with and without the use of MSA collectors. The other parts of the thesis involves evaluation of analysis and design tools algorithm concerning the solar performance prediction. Accuracy and ease-of-use has been assessed. MSA is an absorbing and scattering material in the solar part of the spectrum (0.3 to 3.0 {mu}). It is shown that isotropic scattering may be assumed, as long as the cover thickness is less than 50 mm. Analysis of scattering is usually mathematically very complex and requires a great deal of computational effort. However, a relatively fast and simple method for isotropic scattering within an absorbing and scattering medium has been proposed. MSA has a very low thermal conductivity. However, the material is partially transparent in the infrared between 3 and 5 {mu}. Due to large spectral variation in  More>>
Authors:
Publication Date:
Mar 01, 1991
Product Type:
Thesis/Dissertation
Report Number:
NEI-NO-308
Reference Number:
SCA: 141000; PA: NW-93:005005; SN: 93000928583
Resource Relation:
Other Information: TH: Thesis (Dr.ing.).; PBD: Mar 1991
Subject:
14 SOLAR ENERGY; SOLAR COLLECTORS; EFFICIENCY; PERFORMANCE; SILICA GEL; GLAZING; MATHEMATICAL MODELS; COMPUTERIZED SIMULATION; 141000; SOLAR COLLECTORS AND CONCENTRATORS
OSTI ID:
10120643
Research Organizations:
Trondheim Univ. (Norway). Norges Tekniske Hoegskole
Country of Origin:
Norway
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0802-3271; Other: ON: DE93761363; TRN: NO9305005
Availability:
OSTI; NTIS
Submitting Site:
NW
Size:
163 p.
Announcement Date:
Jun 30, 2005

Citation Formats

Nordgaard, A. Performance prediction of solar thermal systems and the use of monolithic silica aerogel to improve collector efficiency. Norway: N. p., 1991. Web.
Nordgaard, A. Performance prediction of solar thermal systems and the use of monolithic silica aerogel to improve collector efficiency. Norway.
Nordgaard, A. 1991. "Performance prediction of solar thermal systems and the use of monolithic silica aerogel to improve collector efficiency." Norway.
@misc{etde_10120643,
title = {Performance prediction of solar thermal systems and the use of monolithic silica aerogel to improve collector efficiency}
author = {Nordgaard, A}
abstractNote = {This thesis is devoted to a study of active solar thermal systems, and focuses on analysis and design tools. The main part of this work is concerned with development of algorithms for modeling flat-plate collectors that use monolithic silica aerogel (MSA) as part of cover glazing. This study of MSA collectors also includes evaluation of the performance of the collector component, and simulation studies of solar systems with and without the use of MSA collectors. The other parts of the thesis involves evaluation of analysis and design tools algorithm concerning the solar performance prediction. Accuracy and ease-of-use has been assessed. MSA is an absorbing and scattering material in the solar part of the spectrum (0.3 to 3.0 {mu}). It is shown that isotropic scattering may be assumed, as long as the cover thickness is less than 50 mm. Analysis of scattering is usually mathematically very complex and requires a great deal of computational effort. However, a relatively fast and simple method for isotropic scattering within an absorbing and scattering medium has been proposed. MSA has a very low thermal conductivity. However, the material is partially transparent in the infrared between 3 and 5 {mu}. Due to large spectral variation in this region, the radiative transport will not be a local phenomenon anymore, and direct radiative communication between the boundaries may occur. The results of a simulation study of a solar heating system and a combined solar heating and cooling system are presented. In particular, the predicted performance obtained using conventional solar collectors is compared with the predicted performance using MSA collectors. 91 refs., 66 figs., 9 tabs.}
place = {Norway}
year = {1991}
month = {Mar}
}