Advanced solar technology of Solarus applied to landmark Vineyard Hotel

Advanced solar technology of Solarus applied to landmark Vineyard Hotel

The 207-room luxury Vineyard Hotel, in Claremont, Cape Town, is the site of a 60 panel demonstration installation of Solarus Sunpower’s hybrid solar PowerCollectors which will see the 90kWp hybrid photovoltaic-thermal system provide 75kW peak thermal and 15kW peak electric output to the hotel. The system has been endorsed by the Dutch Government who are partially subsidising the cost of installation.

This is the first large scale commercial Solarus installation in South Africa – the company having piloted various residential and hospitality projects over the past two years to prove the concept which is now ready for commercial rollout.

Solarus was founded in 2006 and is headquartered in Venlo, the Netherlands, with a Research & Development centre in Gävle, Sweden.

“There have been many attempts by companies and research institutions to combine the benefits of both PV (Photo voltaic) and T (Thermal) in a single solar panel” explained Henning Brand, Solarus local representative and project manager.

“Achieving this combination has often been dubbed as the holy grail of solar. Solarus has successfully achieved this with our PowerCollector™, and we are now recognised as a leader in the field of hybrid solar (PVT) technology. We have won numerous international awards for both our technology as well as for the way we do business and we are very pleased to announce that the PowerCollector™ is now commercially available in South Africa” continued Brand.

“Solarus PowerCollector™ panels offer a unique benefit of being PVT – that is able to convert sunlight to electricity as a normal photovoltaic (PV) panel and also to provide hot water as a solar geyser (T) in one integrated panel. The introduction of the hybrid solar system has the potential to both reduce the Vineyard’s current and future energy costs while adding security of supply in the maintenance of the hotel’s hot water supply” said Brand.

Space saving

The advantage of this installation, the first of its kind in Africa, is that as both solutions are provided in a single unit providing significant space-saving advantages as well as being more efficient than side-by-side units.

“The Vineyard Hotel and sister properties – Townhouse in downtown Cape Town and Oude Werf in Stellenbosch – are committed to continuously improving the levels of energy efficiency, especially where energy can be sourced from renewable sources,” says Director strategic business innovation Lex Petousis. “Our target was to increase our storage and conversion of solar energy and to produce thermal energy – for heating water, for example.

“The space-saving solution offered by the Solarus hybrid system is highly efficient on our limited roof space, making this system an attractive choice for the Vineyard Hotel and for supplementing an existing solar PV system. We are very proud that the Dutch Government recognized our commitment to sustainable practices and chose to subsidise the installation. We hope that the success of the project will encourage other hotels to follow suit” he said.

The system

The installation consists of 60 PowerCollectors™, which produce four times more total energy than traditional photo-voltaic installations of the same size, while providing heat to a thermal storage of 5,000ℓ – which can be likened to a ‘thermal battery’. Heating is supplemented by two heat pumps and hot water from the five 1 000ℓ tanks gives up heat to mains cold water through a heat exchanger where it is distributed to the ten River Suite hotel rooms, the spa, gym and Splash Cafe. The hot water produced by the system is in a closed loop where energy efficient pumps circulate the water through the solar collectors and back to the storage tanks, never coming into contact with a running tap.

The 15kW of electrical power produced by the system is connected to a grid-tied inverter system. DC power from the panels is inverted to AC and used to power guest amenities, the system’s circulation pumps, heat pumps (when necessary) and control system.

Advanced measurement tools have been installed to record the total output of the system as well as the carbon savings.

State of the art installation

The installation partner for this project is Greenability Installations, a leading service provider in the renewable-energy field in the Western Cape that specialises in solar installations, hydronic underfloor heating, building insulation and double glazing systems.

Joerg Schilling, CEO of Greenability says: “We are always looking to improve our offering with products that give our clients the best solutions on the market. With the PowerCollectors™ we are able to meet two of the most important needs of our clients; heat and electricity, in one system. In the past we installed separate thermal and photovoltaic solar collectors. As the PowerCollector™ ticks both of these boxes installation is quicker and more convenient. The system is also more effective than the independent units.”

Schilling stressed the point that solar installations require in-depth knowledge of thermal dynamics and sophisticated control systems and regrettably there are many examples of underperforming, or even failed, installations installed by unskilled personnel.

Solarus’ joint venture partner for the distribution and the development of projects using the Solarus technology in Africa, is Build Africa Energy, which is part of the Build Africa Group. .  The company also distributes the Power Up hybrid power control system which is the most advanced Solar backup power system available using Crystal battery technology With the Solarus system covering electricity as well as hot water generation and the Power Up system offering safe clean backup power, the company has a complete and unique offering for cost effective  green energy solutions for the hospitality  industry, says CEO of Build Africa, Miles Oates.

Research and Development

Today’s incarnation of the Solarus PowerCollector™ panel represents the culmination of a ten year research and development programme initiated by European energy giant Vattenfall in collaboration with Swedish research institutions and companies including Uppsala and Lund Universities and the Swedish Energy Agency. The result is a panel that boasts 70% solar efficiency without the degradation of its PV properties due to high surface temperatures. Its receiver is able to effectively and uniformly cool the solar cells allowing them to work efficiently under concentrated sunlight through its patented Active Cell Cooling technology-ACC™.

Solarus was formed as a spin off from Vattenfall to market the new hybrid panel system and is currently upscaling its production facilities and rolling out projects to international markets.

“One square meter of such a module will at an input temp of 20°C and output temp of 50°C in Cape Town, give 168kWh/m2/year in electricity and 799kWh/m2/year in hot water, offering great value to prospective future users of solar energy” says Brand. South Africa is one of several countries where Solarus has identified enormous potential.

Sustainability goals

“The Solarus vision is not simply profit motivated – we subscribe to the principles of B(enefit) Corp and Blue Economy and the Solarus PVT panel is the ultimate in sustainability – using the free energy from the sun to power human development. Using electricity to heat water is inherently inefficient, is wasteful, and creates pollution and tons of harmful CO2 through the burning of fossil fuels.

“The potential of this region is enormous – the sun shines most of the time and there are millions of people who either don’t have or have limited access to hot water and electricity. We also have a target market of millions of conventional domestic geysers to aim at that currently heat water in South Africa!” he said.

“The concept is catching hold in Europe and Scandinavia where we have installations running in domestic applications where hot water is not only used for ablutions, but for central heating systems too. Similarly, in hospitals where an added advantage of the hot water produced by our panels can go to 70̊C to make it bacteria free, unlike water at 50̊C which actually encourages the growth of bacteria.”

‘The new power to fuel our future’

“We complain bitterly about the rising cost of energy in South Africa, but further north, they are worse off where many countries pay much more for interrupted and less secure energy supplies’ said Brand. “We see great potential on the continent to fulfil our motto Sunpower for the people!

“With the installation at the Vineyard Hotel, Solarus is making its official entry into the African market. More projects are in progress covering sectors including hospitality, housing, swimming pools, commercial office space, agri-processing and manufacturing” he said.