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Hybrid Heat Recovery and Storage Solution

Netcare Milpark

In collaboration with Spoormaker & Partners and Airgro, SIRAC supplied and commissioned 3 x 7,500L THERMOCUBE™ Heat Accumulator sets which act as a junction for multiple heat sources – Chiller heat recovery and 2 x 100kW SIRAC High Temperature specific SIRAC Heat Pumps.

The THERMOCUBE™ System simply and conveniently connects all aspects of this project together, improving combined efficiency, sanitation and comfort levels.



As an Indirect heating system, the ThermocubeTM  Heat Accumulators enhance the sanitation for the hot water system.

The heated water never leaves the tank and sanitised fresh mains water, at regulated mains pressure, passes through purpose-made 316L stainless steel heat exchangers which are suspended into the hot water within the tank, drawing heat therefrom. This heated sanitised water is then available for distribution.”

This eliminates the threat of legionella growth in the hot water vessels making this the perfect solutions for higher risk environments.


Capital on the Park Hotel – Sandton

SIRAC’S team of engineers simplify and streamline the design process for the professional industry. Our wealth of knowledge and experience in the hot water heating industry enables us to provide clients and design engineers with quick information and component selection advice.

“Gas heating in combination with high-efficiency heat pumps and the energy-saving THERMOCUBE ™ heat accumulators provide an extremely cost-effective and efficient solution for variable heating loads”

Our broad and carefully selected product range ensures that we select the correctly matched components for each job. The installations are tailored to meet the client’s exact needs rather than adjusting their requirement to fit the product.

One such project is the Hybrid – Heat Pump Natural, Gas Heating System at The Capital on the Park – Sandton.

The system was designed to accommodate Highveld winter ambient conditions between-3°C and +40°C. With an expected peak occupancy of 644 people, the Hybrid Plant provides 60,000 litres of hot water per day.

Supplied and Installed:

Two 31kW SIRAC (high-temperature R134a) heat pumps were selected and installed to maintain the base/off-peak heating load of the building. This included the standing ring main losses, hand washing and building cleaning.

Twelve Internally mounted, gas-fuelled heaters fed by the Egoli natural gas pipeline are installed to accommodate the hot water demand throughout the peak periods. These heaters provide high-capacity heating with the ability to re-heat the full storage system within one hour.

Two SIRAC 7,500L THERMOCUBE ™ Accumulator Tanks are installed to provide a constant supply of hot water. The low-pressure storage system with internal 316L stainless steel heat exchangers ensures that regulated temperature hot water is efficiently supplied to the building at all times. This eliminates the fluctuating supply water temperatures often experienced with high-capacity gas heating systems.


Highrise Residential Apartments

Heat recovery systems

16 on BREE CAPE TOWN – Highrise Residential Apartments

At 36 Floors 16 on Bree is Cape Town’s tallest residential tower. In partnership with ER Plumbers and Eckon Consulting Engineers, SIRAC supplied and installed the ThermocubeTM Hot Water Heat Accumulators which provide all hot water storage for the apartments.

The Storage System is heated recovering waste heat from the chilled water air conditioning system. A four pipe chiller provides exceptional efficiency pulling heat from the building and storing this energy as hot water in the Thermocube System. The low pressure storage provides a great neutral point for simple and flexible inclusion of multiple heat sources. The System also includes an electric in-line element heater, manufactured and supplied in-house, for back up during chiller maintenance periods.


Heat Recovery System – 4 x 11,000L Thermocube Systems supplying all the hot water to the building.

Inner City Revival

Towers Main – Johannesburg CBD

In collaboration with WSP Johannesburg, SIRAC supplied and installed a large hot water installation for iThemba Properties Towers Main development.

The challenges of re-developing building in tight quarters were easily overcome by installing the flat panel ThermocubeTM Hot Water Storage System. The Heat Accumulators were delivered and then constructed on site in position.

The rooftop plantroom houses 2 x 15,500L and 1 x 11,000L Thermocube Heat Accumulators with 6 x 62kW SIRAC High Temperature R134a Heat Pumps.

The ability to heat the water beyond 60°C with the heat pumps not only improves system sanitation it also guaranties high comfort levels for all occupants throughout the expansive hot water network.


15th Floor Installation:

  • ABSA Office Suite – 1,600L Thermocube with 2 x 15kW High Temperture R134a Heat Pumps
  • TOWERS MAIN Lower Level Apartments – 2 x 7,500L Thermocube with 4 x 31kW HighTemperature Heat Pumps

Student Housing

Uct avenue road residence – turnkey projects

With its water and energy savings and full suite of disability features, the University of Cape Town’s (UCT) new 500-bed Avenue Road Residence is the first South African student housing development to be awarded a Green Star rating from the Green Building Council South Africa (GBCSA). The project achieved a four-star rating.

In partnership with Plumbcon and WSP,  SIRAC supplied and installed a turnkey hot water installation for the new University of Cape Town Residence in Observatory:


Relying solely on Heat Pumps for the water heating the system is incredibly efficient. 

4 x High efficiency 90kW SIRAC, Environmentally friendly R410a Heat Pumps. Providing all the water heating for the facility. 


SIRAC Built up and installed the Grundfos Booster Pump Set, which provides pressurised potable hot and cold water throughout the facility.


3 x 10,000 Insulated 600kPa Hot Water Storage Vessels with zero power consumption.

Tight workspaces made for a tricky installation but the three 10,000L hot water vessels fit neatly within the confines of the hot water plant room.

Related Products:

  • SIRAC 90kW R410a high Efficiency Commercial Heat Pumps
  • Bulk Hot Water Storage Vessels
  • Booster Pump Sets and Controls

Social Housing

DISTRICT SIX – Split Type Heat Pumps

SIRAC is proud to have played a part in this historic re-development of District 6 in Cape Town. With 108 apartments finished and land redistributed to the displaced occupants. SIRAC provided and installed the hot water heat pumps and storage cylinders for each apartment.

Each Apartment is provided with a 150L Geyser and 7kW SIRAC Heat Pump water heater.


Hybrid Systems

Ukzn – Edgewood Campus

In search for the highest level of energy efficiency the University of Kwa-Zulu Natal commissioned SIRAC to supply and install a high tech installation incorporating Solar Thermal and Heat Pumps to generate hot water for two residences at their Edgewood Campus. The system was paired with a Photovoltaic collector system with super capacitor energy storage.


With combined energy savings of nearly 90% when compared with historic system consumption.

The system is also paired with advanced monitoring capabilities which ensure that the heat pump back up heating is carefully controlled stepping each compressor circuit on demand with an anticipation of solar energy calculated into the decision making.

System Installed

  • 20 x 2m2 Flat Plate Solar Collectors
  • 1 x 7,500L Thermocube Heat Accumulator Storage System
  • 2 x 35kW High Efficiency SIRAC R417a Heat Pumps



SIRAC Southern Africa (Proprietary) Limited
23 Reen Avenue


Cape Town

South Africa

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