Buoyancy-driven convection in cavities with particular application to the development of a low cost solar water heating system

  • Jose Manuel dos Santos Cruz

Student thesis: Doctoral ThesisPhD

Abstract

The overall aim of the research reported here was the development of a simple, low-cost passive solar heating system for operation in the Portuguese climate. The performance of this device is critically dependent on the rate of convective heat exchange across the cavity behind the heater plate. Both computational and experimental studies of the heat transfer characteristics of this new storage device, have been conducted.

An experimental installation in full scale was designed and constructed to enable the measurement of local heat transfer rates. Computer simulations of the laminar flow under solar-driven conditions were made using an existing steady, three-dimensional computational fluid dynamics (CFD) code based on the finite-volume method (PHOENICS Code shareware version 1.5). A boundary-fitted co-ordinate system was developed to fit the non-rectangular geometry of the cavity, that represented the water store, which provided the computational grid for the CFD code.

The experimental data from the test rig was used to validate the CFD model. A solar water heating system was built to test the design under realistic weather conditions.

The experimental thermal performance was evaluated in 48% while the theoretical was estimated in 51%.

Date of Award3 Dec 1997
Original languageEnglish
Awarding Institution
  • University of Bath

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