Showcasing solar cooling in South Africa: The Netcare Moot Hospital in Pretoria has installed the first cooling system based on a solar thermal powered absorption chiller. Photo: Voltas Technologies
The first “Solar Thermal Driven Chilled Water System” (STDCHW) in South Africa is up and running: The showcase project includes a WFC 10 chiller (cooling capacity: 35 kW) by Japanese manufacturer Yazaki and a solar collector field of evacuated tube collectors. The South African company Voltas Technologies (PTY) Ltd. implemented the system on the roof of the Moot Hospital in Pretoria in partnership with several other solar installers. The goal here was to demonstrate the economics and the operating characteristics of absorption cooling systems under South African weather conditions.
There are only a few cooling systems based on thermal-driven sorption chillers in South Africa to date - and none has been a solar-powered one. Building developers are finding themselves in a situation, in which electricity permits and allowances are more and more difficult to obtain and many are now exploring how viable solar and eco-friendly technology can be as alternatives. In 2008, Cristian F. Cernat, CEO of Voltas Technologies, finalized a distribution agreement with Yazaki.
“The project’s results will be available shortly and will prove that absorption technology is the optimal air-conditioning solution for South African's environmental conditions”, Cristian F. Cernat, CEO of Voltas Technologies, stated.
Photo: Voltas Technologies
The major challenges Voltas Technologies is facing today are structural limitations of existing buildings and the need to prove that absorption chiller technology could be an ideal solution for the South African market. The STDCHW project is an important step in overcoming market barriers. The Netcare Group Management realised this clear opportunity and provided sufficient roof space and is able to operate the system within the existing air conditioning plant. ““The installation uses solar energy instead of electricity to produce the chilled water needed to operate the building's air conditioning system,” Cernat explains. “Thus, utilizing solar thermal energy becomes an efficient process: It can not only provide for cooling in summer, but also for hot water and space heating in winter.”
Finding the right ratio between kW cooling capacity and required solar collector area under South African weather conditions became the focus point for all cooperating partners. “We validate the ratio between cooling capacity and solar absorption area when it comes to evacuated tube collector, U-tube and heat-pipe types,” Cernat explains. Furthermore, the CEO wants to optimise the company's heat storage solution, in order to ensure a constant hot water supply to the chiller and a 12-hour operation of the system.
“A performance report will be available soon," states Cernat. Once conclusive data has been collected and the heat source/cooling ratio confirmed, the project will move to the next stage - upgrading the system to 200 kW nominal cooling capacity.
Voltas Technologies Pty Ltd provides customised heating and cooling solutions based on solar technology. The company holds the South African distribution rights for a number of sorption systems, including manufacturers like Broad (China), Yazaki (Japan) and Sortech (Germany).
Text was written by communication specialist Hanna Schober based in South Africa. Schober@solrico.com