Free energy for Fort Hare University
Tuesday, 10 August 2010 10:14 Nondi Nkonzo
Fort hare, situated near Alice in the Eastern Cape, is an iconic university with great statesmen such as Nelson Mandela as an alma mater.The University of Fort Hare is near East London, South Africa’s forgotten city and once economic hub of the Eastern Cape. In keeping with the global initiative to go green, and being a leader in its class, the university decided to install solar water heaters on some of its residences so as to be less dependent on ESKOM and to reduce its carbon footprint.
The installationsThe final tender was awarded to Kei Boilers (KBS) in Port Elizabeth (PE). This company specialises in the manufacturing, and installation, of large heating vessels.
Managing member of Kei, Devon Muller, was excited to be involved with this green energy project and he immediately involved a solar company Solar Reaction, also from PE. Eric Higgs, CEO of Solar Reaction, says his company is PIRB accredited and they have installed many solar water heating systems in and around PE.
They use the TASOL brand of solar products supplied by Solar Academy of sub-Saharan Africa (SASSA) from Johannesburg. Research manager at SASSA, Ronnie Mulder, assisted with the sizing and design of the system according to supplied specifications. He uses TSOL, free energy for Fort Hare University Fort hare, situated near Alice in the Eastern Cape, is an iconic university with great statesmen such as Nelson Mandela as an alma mater. a solar simulation software package, for thermal system performance verification.Two residences were chosen for this project. Jabavu has 6x1800L boilers with 60 20- tube AKH Tasol evacuated tube collectors on the roof. Jalobe has 2x3000L boilers with 20 collectors for each boiler, as well as 1x2400l boiler with 15 collectors on the roof. All the boilers have electrical back-up in case of persistent bad weather. An example of the simulation output is shown below for the JABAVU residence. Not all the details are shown since the program has many features and for the sake of brevity, only some important parameters are given.
The controller
A Geyserwise controller was chosen as the solar management system because of some unique features. Some of these include a “holiday mode” that prevents overheating of the system during holidays by wasting excess energy and prevents temperatures above 50°C.
A Geyserwise controller was chosen as the solar management system because of some unique features. Some of these include a “holiday mode” that prevents overheating of the system during holidays by wasting excess energy and prevents temperatures above 50°C.
It has an anti-frost protection mechanism that prevents temperatures in the plumbing, near the collectors, of below 5°C. It has the usual “delta-T” function to properly control the pumping cycles of the water from the collectors to the boilers. It also controls the electrical contractors for the heating elements, when required via its onboard timer settings. A host of error codes supply valuable information to system faults. It has a kWh logging facility so energy to the elements can be logged.The circulation pumps were also sized used software, so as to compensate for head losses due to pipe friction and other system losses. 42 mm class1 copper pipes were used and the flow was designed to be 2 l/ min per collector.
The collectors were connected five in series and then in parallel so as to minimise pressure losses in the pipes. The hot water reticulation was done by KBS and Solar Reaction and the boilers and manifolds were supplied and fitted by KBS.
From the simulation program it is predicted that the university will save 108.5 MWh of energy per annum on the JABAVU residence alone. This equates to 108 500 kWh and @ R0.75 per kWh amounts to cash saving of R81 375 per annum, says Mulder.
www.heatingandcooling.co.za
