Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
Solar thermal technology is a booming market. As a result, a
wide range of solar thermal collectors and systems are produced
by numerous manufacturers all over the world. In order
to assess thermal performance, manufacturing quality, safety of
operation and to identify potential for further improvement,
accurate testing of solar thermal collectors and thermal solar
systems is required. Standardized testing procedures for solar
thermal collectors are e.g. specified in the European Standard
EN 12975 or the international standard ISO 9806 and for solar
thermal systems in the South African Standards SANS 1370
(Mechanical tests) and SANS 6211-1 (Thermal tests) as well as
in the international standards ISO 9459-2 (CSTG-method) and
ISO 9495-5 (DST-method).
In order to secure a growing market for solar thermal products
in South Africa and its neighbouring countries, it is essential to
establish a solar thermal test institute as a service provider for
manufactures and suppliers in the Southern African area. For
this purpose, a turn-key test facility for solar thermal collectors
and systems was purchased from the German company Solarund
Wärmetechnik Stuttgart (SWT). SWT is a spin-off company
from the Institute for Thermodynamics and Thermal Engineering
(ITW) of the University of Stuttgart. ITW has been
working in the solar thermal field for more than 30 years and is
operating the “Research and Test Centre for Thermal Solar Systems”
(TSZ). The TZS is the largest solar test centre in Europe.
Hence, very substantial experience related to testing and the
construction of test facilities has been gained at ITW and SWT.
The test facility for the South African Bureau of Standards
(SABS) is part of a project financed by the Central Energy
Fund (CEF) and the United Nations Development Program
(UNDP). The facility was manufactured and instrumented by
SWT based on a standard office container as a turn-key product.
Before the test facility arrived from Germany, two staff
members of SABS were trained for one week at SWT in Stuttgart,
Germany. An additional training program took place onsite,
after the test facility had been set-up and commissioned in
Pretoria. The initial operation was performed together with an
expert from SWT.
After shipment to South Africa the test facility could be taken
into operation within a few days at the South African Bureau of
Standards (SABS), located in Pretoria. The South African Bureau
of Standards has been working with the mobile, standalone
test facility since the beginning of 2007 and has already
tested several systems according to SANS 6211-1. To-date, the
experiences gained with the mobile, stand-alone test facility are
very good. It operates without notable problems and delivers
reliable and accurate results.
The paper describes the principle set-up of the test facility as
well as the experience gained by SABS.
The heat transfer properties of phase change materials (PCMs) are of importance for the efficiency assessment on the heat storage and release in solar thermal systems. Previous research results demonstrate that the increase ...