Introducing the new ACCUMULATOR
by ThermoWise.

Conventional calorifiers have been in the market for as long as hot water has been consumed on a commercial scale. The primary downfalls of this technology are (1) lifespan, (2) installation challenges for retrofit or replacement in existing areas where access is limited.

Every few thousand years a major evolutionary jump, is observed in nature. Single celled organisms in the oceans became multicellular, these then evolved further and developed self-propulsion, then became foragers and then became predatory and started hunting for food `and eventually took the first steps on dry land.

It is time for hot water generation and storage to evolve and take its first steps out of the oceans of old technology and onto the dry land of the future, and the evolution has come. The commercial hot water industry has been calling for it and at ThermoWise we are proud to present it – The ACCUMULATOR.

Heat Accumulator


The ACCUMULATOR vessel is made of high-density polyurethane foam panels, sandwiched between two layers of Chromadek. This construction offers flexibility of installation in confined spaces or spaces with limited access and gives the vessel outstanding thermal insulating properties.

Because the vessel is built from these panels both on the base, side walls and lid assembly, the vessel is well insulated against heat loss via radiation or conduction to the substrate and surrounding atmosphere. This eliminates the process of lagging and cladding entirely which reduces construction time and guarantees uniformity and quality of the finished product. The Chromadek is treated with a primer and a zinc coating which gives it anti-corrosion properties, this is then coated with a final colour for a semigloss appearance.

Vessel Construction




The walls are supported by an aluminium extrusion framework for structural strength and rigidity to withstand the hydraulic forces acting on the side walls. The use of aluminium for this structure over cheaper materials like mild steel further adds to the longevity of the unit, as the aluminium will not corrode over time due to exposure and aid in reducing the total weight of the unit. Weight saving has always been a factor in commercial hot water when a plant is being installed on a suspended slab or steel platform. Reducing the total mass of the assembly reduces the dead load of the system, thereby reducing the cost on the supporting structure required.

The bladder or water proofing layer inside the vessel is Firestone’s EPDM Geomembrane, a product long used in industry for irrigation reservoirs and canals, agricultural pits and ponds, constructed wetlands and more. The product is UV stable, offers an excellent elongation modulus and will stretch over 300% without failure, can be easily installed and repaired without having to remove the lining from the vessel first, and comes with Firestone’s 10yr warranty.

The heat exchanger coils suspended in the water column are available in 304 stainless-steel and 316L stainless steel variations. The latter being more expensive to install but offering a higher anticorrosion resistance and thus longer lifespan in return.

The coils are SABS approved, JASWIC certified and come with a 2yr standard warranty. They are easily replaced with minimal downtime to the system and minimal water loss during the process thanks to the modular design of the system. Any one of the heat exchangers in a system can be removed and replaced in a matter of minutes.

The ACCUMULATOR is designed as a project specific solution to hot water generation and storage. The required flow rates through the heat exchangers should be known at the onset to determine the best layout of the heat exchangers to prevent excessive pressure drop across the unit and to prevent inadequate transfer of heat energy to the domestic hot water circuit.

Table 1, Chemical composition of heat exchanger material options.

Table 2, Resistivity of heat exchanger materials in chloride solutions.


The ACCUMULATOR can be simultaneously heated by multiple sources without cross contamination. Such as integrated solar heating circuits to maximize free energy.

The ACCUMULATOR is designed primarily for heating through a ThermoWise heat pump, but induction element backup supply can be coupled into the system.

Heat recovery circuits can be integrated for higher overall building efficiency. Using recovered heat such as that off existing HVAC systems to reduce the required primary input heat source capacity.

The ACCUMULATOR logging and data collection can be integrated into the system as a packaged unit.

The ACCUMULATOR can be supplied fitted with a control panel for BMS integration to MODBUS or BACnet, offering an RS485 communications port for data collection.

The ACCUMULATOR can be disassembled and repositioned at a later stage should the site conditions or needs change from the time of installation.

The ACCUMULATOR heat exchangers are SABS tested to 8MPa without failure.

The ACCUMULATOR heat exchangers are SABS tested for water hammer over a 2000 cycles test during which the samples were suddenly pressurized from 350kPa to 2 000kPa in 1sec without leakage or failure.

The ACCUMULATOR maintenance is simple and easy, this can be integrated into the service level agreement of the heat pump and circulating pump equipment either annually or biannually.


The ACCUMULATOR heat exchangers come with a 2yr warranty. The overall lifespan of the heat exchanger is subject to site conditions. Average life expectancy is 15yrs – 20yrs.

The ACCUMULATOR vessels come with a 5yr warranty.

The ACCUMULATOR lining comes with a 10yr warranty.

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Weather-compensated heating circuit control unit as an easy-to-operate control unit with plain text and graphic display

For one heating circuit with mixer and cylinder temperature control


For controlling a cylinder loading system with mixer assembly


High control quality by adapting to different user profiles.

Control for systems with or without circulation.

Thermal disinfection function

Day / Week programming for various functions

Cascade of up to 4 units possible

Provision to connect flow sensor for exact DHW measurement – V-Bus/0-5V/0-500 Hz/Impulse input

PWM Pump control

Clear system graphics in user interface

Inputs: 5 temperature sensor (Pt1000), Flow sensor

Outputs: 2 PWM, 2 Semiconductor relays, 1 potential free contact

Supply voltage: 100 – 230 V, 50-60 Hz

Protection class IP 21

Operating Temp : 0 – 40 C

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Telephone: +27 32 947 0377
Fax: +27 32 947 0349
Share Call: 0860 HEAT H20 / 0860 4328 420

Physical Address
Corner of Umkhoba & Umzithi Road
Etete, Dolphin Coast, Shakaskraal
KwaZulu-Natal, South Africa
GPS Co-Ordinates
-29.426958, 31.228099
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Postal Address
PO Box 6980
South Africa


Telephone: +27 11 450 1418
Fax: +27 86 602 0311
Share Call: 0860 HEAT H20 / 0860 4328 420

Physical Address
88 Driehoek Road
Germiston 1401
Gauteng, South Africa
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