SOLAR Cooling, Co-Generation THE BANK

BLACKDOT Energy designed a Solar Cooling, Co-Generation solution for the Rosebank Project, THE BANK.

Aptly named, this building located in Rosebank, Gauteng, is the product of a complete re-development of an old bank building that had substantial design changes mid-construction, and a solution to fit.

The design aesthetic celebrates the history of the original building. The deep facebrick façade created an impression of strength and resilience, which is softened by the various incorporated greenery. The building then de-fragments at the top into a minimalist crown-shape, which creates deep landscaped roof-gardens offering magnificent views of the Johannesburg skyline.

The new design then called for a conversion into a high-rise building, and initially four-storeys on top of the original structure were to be added. What changed the development quite drastically mid-way, was that the owners decided on a higher design and thus required an additional three storeys more be included. So, this then became a 12 storey building - excluding the ground floor. The entire re-development also made use of the original building’s foundations.

There was a very limited power supply from the council to the building (600kVA), and that brought into the design brief the requirement for an alternative source of power, and thus highly-efficient systems, which the VRF system meets.

To solve the power scenario, and which was another technological advancement that was added to the building, was the implementation of a gas generator. The building was determined to require at least 1200kVA. To provide this power requirement BLACKDOT ENERGY deisgned a Hybrid renewable Co-Generation solution consisting of a Solar PV rooftop installation of 90 kVa, an onsite 416kVA gas generator was installed, supplemented by a COJ 600 kVa connection. As a system redundancy the 700kVA diesel backup generator is in place should the COJ connection be lost.

The Co-generation solution enabled the entire hotels hot water requirements to be provided from the generator waste heat. This is recovered through heat exchangers from the engine block and exhaust heat. The heat recovery enable a large electrical baseload reduction, by not having to provide the hotel hot water requirements through electrical heating, but from recovered heat in the Co-Gen system resulting in substantial cost saving.

All three of these power sources feed through a synchronised supply into the building. So the primary means of power supply to this building is now a mix of the gas generator and Solar PV, and the shortfall provided by council supply, designed and implemented by BLACKDOT ENERGY.

The hot water system for the hotel is also implemented on this services level. A 7,600 litre tank was installed which is heated from the second floor gas generator plantroom, and the buildings hot water ring main is circulated from here. This services level also houses the heat evaporation units that dumps the remainder of the generator waste heat to the back of the building.

Renewable energy was a core design element, the buildings entire available roof space was covered with a solar PV panel array, this power generation system feeds directly into the buildings main grid intended to supply the baseload power requirement for the day time HVAC system. The solar PV serves as a first phase of Solar Cooling design that is strategically planned for the Blend Properties group in a planned strategic roll-out to their other property portfolios.

From an Energy security and redundancy supply perspective, having the ability to control and generate your energy requirements on-site, results in a competitive energy reliable property portfolio. If the building supply was grid connected to a 1200 KVA COJ supply (which would have cost R3 million just for the upgrade connection), would then require an additional 1200 KVA Diesel backup redundancy reuirement. With this Hybrid renewable Co-gen design, the generation capacity is controlled onsite, only requiring a Diesel back up capacity for the COJ supply.

Tri and co-generation power solutions are very new to the industry and there are also not a lot of companies that specialise in this field that can supply solutions based on the various needs of the client. BLACKDOT ENERGY is one of the scarce companies in South Africa who were able to provide a solution for this building. In 2018 BLACKDOT ENERGY deisgned and implemented the first Solar Co-Generation district heating system, including South Africa in the list of only 25 countries globally with Distric Heating technology, and included in several international press releases.

Видео SOLAR Cooling, Co-Generation THE BANK канала Blackdot Energy Engineering