Renewable energy, and in particular solar energy, has been getting a bit more attention over the last couple of year. Not only because it lowers the carbon footprint of whoever is using it, but it is also cheaper.
Mobile operator MTN has taken that to heart, and installed Africa’s first concentrated solar cooling plant at their 14th Avenue Data Centre in Johannesburg. The plant will be used to power the air conditioning system for the entire building, saving it money and lowering their dependence on the local electricity grid.
“You wouldn’t normally associate a telecommunications company with energy efficiency, but this isn’t our first renewable energy project. Our tri-generation plant installed a couple of years ago powers the very building we are in. We have a number of renewable energy projects, and have been recognised in the space,” MTN said during a press conference.
The system consists of 242 solar mirrors covering a total area of 484 square metres, which track the sun to generate pressurised hot water at 180 degrees Celsius. The hot water in turn powers an absorption chiller that produces chilled water circulated into the data centre for cooling of IT equipment.
It is driven by technology called Linear Fresnel Concentrating Solar Power (CSP) and has a peak cooling capacity of 330 kW.
“The mirrors follow the movement of the sun, based on the GPS location, orientation and the date and time. This information guides the system to track the sun to concentrate on the central absorber tube where heat is generated,” MTN explained.
The Solar Cooling Plant is a collaboration between MTN, Industrial Solar, Voltas Technologies and Luft Technik, and supported by the German Energy Agency (DENA)
“This project is part of the worldwide ‘Dena Solar Roofs Programme’ coordinated by the German Energy Agency – and supported by the German Federal Ministry for Economic Affairs and Energy (BMWi). We are happy that this innovative system generating green energy is now a part of the MTN strategy to reduce its carbon footprint. So this lighthouse project is a win-win-situation for all,” said Gabriele Eichner from DENA.
For those that want a little bit more technical detail, the solar field consists of:
- Number of Modules: 22
- Module Dimensions (h,w,l): 4.5m, 7.5m, 4.06m
- Primary Mirrors: Glass with metal support structure Number of Mirrors: 242
- Mirror Arrangement: 2*11 Rows Mirror Area: 484m2
- Control: Closed-loop Mirror Tracking: Uniaxial
- Primary Motor Drives: 24V, 15W
- Number of Motors: 22
- Secondary Reflector: Highly Reflective Aluminium
- Absorber Tube: Schott PTR 70 (vacuum)
- Solar Loop Fluid: Superheated Water
- Operating Temperature: 180°C Operating Pressure: 16bar
- Specific Weight: ~28kg/m2
- Specific Thermal Peak Power: 562W/m2 (at reference conditions)
- Peak Thermal System Capacity: 242kW
- Annual Gross Heat Production: 391MWh