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GENERGY: 1,26-kL Solar system with 13 m2 Evacuated Tube Collectors


TOTAL M2 Panels 13
Tank Storage 1,260
Year Commisioned 2012
Tank Construction Integrated Heat Pump Mild Steel, Vertical
High / Low- Pressure Storage High Pressure
Litre / m2 97
System Capex Cost R350,000
Rand / m2 R6,731
Energy Savings / Annum kWh 75,000



Every administration 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 Truworths Head Office 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 Truwoths on their Energy Efficiency Campaign, 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 office block facility was designed to accommodate up to 1200 users per day over a normal 8 hour shift as well as a restaurant that serves 700 meals per day. This equates to approximately 5 000 litres of hot water at 60°C per day. The facility consists out hand wash basins on every floor, a shower on every floor and the restaurant. Space availability is a constraint as there is limited space available of the rooftop.
Existing hot water facilities included a 2300 litre hot water storage vessel with 36kW of electrical resistance heating


A total of 8 evacuated tube solar thermal collectors, each covering an area of 2m², were installed at a tilt angle of 23° to ensure optimal year round performance of the solar thermal system. The orientation of the roof slab was North West which allowed for peak afternoon solar yield. The collectors were installed in 1 bank of 4 in series and 2 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 100% water and operated as a direct system. Expansion tanks were used to accommodate expansion and retraction of the fluid inside the closed solar loop. The integrated heat pump used at this installation had sufficient ports available for a dedicated solar loop.

Four off 6.2kW air source integrated 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 integrated heat pump vessels had a combined storage capacity of 1 260 litres, each one being 315 litres. 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. An effective 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.


Tel: +27 86 115 9159

Address: 3 Alabaster Road, Baakens Valley, Port Elizabeth





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