Dynamic model of a small scale concentrating solar cooker with rock bed heat storage

Journal of Energy in Southern Africa. 2016;27(1):20-27 DOI 10.17159/2413-3051/2016/v27i1a1563


Journal Homepage

Journal Title: Journal of Energy in Southern Africa

ISSN: 1021-447X (Print); 2413-3051 (Online)

Publisher: University of Cape Town

Society/Institution: University of Cape Town

LCC Subject Category: Technology: Mechanical engineering and machinery: Energy conservation | Geography. Anthropology. Recreation: Environmental sciences

Country of publisher: South Africa

Language of fulltext: English

Full-text formats available: PDF



Karidewa Nyeinga (Makerere University)

Ole J Nydal (Norwegian University of Science & Technology)

Denis Okello (Makerere University)

Eldad J.K.B. Banda (Makerere University)


Double blind peer review

Editorial Board

Instructions for authors

Time From Submission to Publication: 18 weeks


Abstract | Full Text

This study presents a dynamic model for a concentrating solar energy collector with an integrated rock bed heat storage system. The model is based on numerical integration of a set of conservation equations for mass, momentum and energy of the heat carrier, the rock pebbles and the walls. The heat carrier is compressible air. Numerical solutions are implemented based on implicit time integration without iterations. Stability problems at large time steps do not occur but the accuracy is reduced. The model predicts pressure, velocity, density and temperatures of the fluid, rock bed and wall in time and along the bed. The model is validated with experimental results in a laboratory setting on temperature profiles during charging and discharging of rock bed heat storage. The intention is that the model shall serve as a computational tool for upscaling of air based concentrating solar energy systems with rock bed heat storage units.