Xstrata Elands Mine
GENERGY: 60-kL Solar system with 504 m2 Evacuated Tube Collectors
TOTAL M2 Panels 504
Tank Storage 60,000
Year Commisioned 2011
Tank Construction Mild Steel, Vertical
High / Low- Pressure Storage High Pressure
Litre / m2 119
Energy Savings / Annum kWh 1,800,000
SHORT DESCRIPTION OF THE SYSTEM
Every mineral processing facility knows that a rand saved on overheads is a rand gained towards the sustainability of the facility. Traditional methods of water heating, such as electrical resistance heating, have been used for years in the South African market with great success and reliability. With the rise in energy costs in South Africa over the last few years, consumers have become more innovative in their approach to energy efficiency and renewable energy.
Fortunately for Xstrata Elands Platinum their management team has established those improvements on the energy efficiency of their facility is a fantastic way of reducing overall operational costs. Thus, when Genergy was given the opportunity to partner with Xstrata Elands on the newly built division, we jumped at the opportunity. The opportunity allowed Genergy to design, supply, install and commission an energy efficient hot water system making use of solar thermal technology as the primary source with heat pump as a secondary source.
“Projects like this are an investment in the future of sustainable mineral processing”
The energy efficient hot water system at the change house of the facility was designed to accommodate up to 1500 users per day over three 8 hours shifts. This equates to approximately 100 000 litres of hot water at 60°C per day. From the 100 000 litres of hot water used per day approximately 15% is used in the nearby laundry for washing. The facility consists out of two change house next to each other. The project was implemented in 1 phase, starting off with accommodating 500 users and the remainder of the users over a duration of 5 years. A 1500m² concrete slab was constructed for the implementation of the solar thermal hybrid heat pump system and plinths for heat pumps and boilers specifically designed to rig the equipment.
CHARACTERISTIC’S OF THE SYSTEM
A total of 160 evacuated tube solar thermal collectors, each covering an area of 4.9m², were installed at a tilt angle of 28° to ensure optimal year round performance of the solar thermal system. The orientation of the slab was north which allowed for maximum daily solar yield. The collectors were installed in 4 banks of 5 in series and 8 in parallel on the Tichelman’s reticulation principle to ensure uniform pressure and temperature of the solar collector array. Two inline circulating pumps, controlled by a temperature differential solar controller, ensured the optimal flow rate of the fluid conduit inside the closed loop. The fluid conduit exists of a 60% water and 40% food grade glycol mixture to prevent freezing and overheating of the closed loop. Expansion tanks were used to accommodate expansion and retraction of the fluid inside the closed loop. The internal heat exchangers fixed inside the hot water storage vessel were made of a corrugated flexible metal hose to increase surface area and promote better heat transfer to the water inside the vessel.
Four off 45kW air source heat pumps were installed as a secondary form of water heating. The four heat pumps ensure sufficient hot water recovery between usage peaks even when no solar radiation is available
The hot water storage vessels had a combined storage capacity of 60 000 litres, each one being 15 000 litre. The vessels and all associated pipework is lagged and cladded to reduce heat losses in storage and reticulation.
A reduction of 90-95% in the energy used for water heating is achieved, thus a reduction in operational cost of the facility. Work load of the heat pump water heaters are reduced ensuring longer lifespan and reduced maintenance/replacement cost. A 90-95% reduction in carbon emissions when compared to electrical resistance heating
A payback period of less than 5 years and an effective lifespan in excess of 10 years and an increased value of the facility .
CONTACT INFORMATION:Tel: +27 86 115 9159 Mail: email@example.com Web: http://genergy.co.za/
Address: 3 Alabaster Road, Baakens Valley, Port Elizabeth