Solar thermal energy - Flat collectors

Flat collector RA 251/4

Efficient conversion of solar energy into heat

Heating costs account for the largest share of energy costs. More than 80 percent of domestic energy consumption is attributable to space heating and hot water preparation. By including solar energy, this cost block can be significantly reduced. With its 2.5 m² surface area and variable connections, it can cope with almost any task.

The advantages of the RA 251/4 flat plate collector at a glance:

Highest solar yields due to blue, highly selective Tinox vacuum coating
Durable thanks to hail-resistant safety glass, double-walled aluminium frames and permanently tight cutting ring connections
Optimum use of space due to horizontal and vertical installation

more than 525 kWh/m² per year

Use of minimum solar radiation through combination with the Oskar° stratified tank and/or a heat pump
A completely coordinated system with other ratiotherm components

It is more than a normal solar collector and represents an important building block in the overall system for the use of the free solar energy source, whose potential is only partially exploited. Unlike pure fair-weather solar systems, our RA 251/4 flat-plate collector captures even the smallest ray of sunlight.


In combination with the Oskar° stratified storage tank or the WP Max-Air hybrid heat pump, additional heat gains can be achieved even at temperatures below 35 °C. The solar collector RA 251/4 can be used to capture even the smallest solar rays.


The RA 251/4 flat-plate collector is designed as a harp collector and can therefore be used in a very wide range of applications. Whether flat, pitched or saddle roof, we supply the appropriate mounting material. The installation as a high-quality and attractive facade element is also possible.

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