Concrete core cooling with supply air

An innovative symbiosis between component temperature control and supply air creates comfort with high energy efficiency through maximum utilisation of free cooling. Supply air induction is practically invisible,resulting in above-average user satisfaction.

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High energy savings through maximum use of free cooling and an overall heat recovery rate of > 95 %.


The air ducts are not visible from within the room – air diffusers are unobtrusively integrated into the concrete ceiling or corridor partition wall.


The cooling medium is air, so there is no risk of it freezing on building sites in winter, and drilling into the tubes will not result in water damage.


Cooling tubes with 60 or 80 mm diameter, made of aluminium that conducts heat very well, are cast into concrete ceilings, in line with the building grid. The tubes are finned on the inside for improved heat transfer. Supply air is not delivered directly to the interior; instead, it initially streams through the cooling tubes within the concrete ceilings. This warms the cold supply air to approximately the same temperature as that of the ceiling. The heat required is drawn from the ceiling itself. The removal of heat simultaneously cools the ceiling. The supply air is then fed to the interior via Kiefer air diffusers, providing the fresh air changes necessary to meet hygiene requirements. A discharge temperature of approximately 21 °C is achieved for the supply air without the need for supplementary heating. The process is self-regulating and virtually free of fluctuations, providing excellent temperature stability due to the high storage capacity of the concrete ceilings. Heat recovery by the air handling system is raised to over 95 % by incorporating the CONCRETCOOL system. This exceeds all requirements set out in the German Renewable Energies Act (EEWärmeG).

Cooling capacity (transient) 30 - 70 W/m²
Tube diameter 60 and 80 mm
Material Aluminium
Heat transfer up to 90%
Ceiling strength 22 – 30 cm
Specific air flow rate 6 - 7,5 m³/hm²

Invisible air ducts in the concrete ceiling or corridor partition wall

CONCRETCOOL cooling tubes are available in 60 or 80 mm tube diameter. The heat transfer efficiency of the installed tube in the concrete lays between 20 and 30 W/m²K.


Installation situation

The cooling tubes can be installed with concrete cast in-situ, filigree ceilings and factory cast slabs. When sizing the CONCRETCOOL system units, an individual technical solution is drawn up for each project.

CONCRETCOOL in the planning stage

We will prepare a CONCRETCOOL system proposal for you at no cost. We would be pleased to draw up a control concept for the optimum use of our system in connection with the air handling system. As air conditioning experts, we also offer you a full range of services in air handling technology – from the planning stage all the way through to commissioning.

Cooling tube in combination

with GLS 230 ceiling air diffuser; connector behind the ceiling panelling
CONCRETCOOL detailed drawings

Cooling tube

with the INDULSNAP wall air passage; supply and extract air version

Cooling tube in combination

with the INDUL linear air diffuser behind the ceiling panelling
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Kiefer Klimatechnik GmbH

Kiefer Klimatechnik GmbH is a leading company in the field of ventilation, air handling and air conditioning technology. Our range of services includes consulting, planning and execution of systems for thermal comfort and industrial air conditioning, as well as the associated installation and maintenance. For more than three decades, Kiefer has also been selling high grade ventilation components worldwide, such as linear diffusers, wall passages, displacement outlets, light and acoustic sails, chilled ceiling panels and concrete core cooling systems, developed in the company's own laboratories.

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