Thermal solar system
ROTEX Solaris

The high-performance solar system for hot water and heating support.

ROTEX Solaris uses free solar energy and thereby supports the heating system. Solaris flat collectors are available in three versions. They can be used flexibly in on-roof, in-roof or flat roof mounting. All ROTEX thermal stores are already optimized for the use of solar energy. In combination with the ROTEX thermal storage tanks, the free-of-charge power of the sun is exploited in a highly-effective manner for hot water generation and heating support. This combination convinces by its highest level of energy efficiency thanks to low heat losses, perfect water hygiene and unlimited hot water convenience.

System advantages

For the health of your family

ROTEX thermal store with hygienic freshwater technology.

Flexible combination

Perfect connection to different heating systems.

For each roof

Possible as on-roof, in-roof or flat roof installation.

For all applications

Choose between efficient Drain-Back or flexible pressure solar system

Product description

ROTEX Solaris high performance solar collectors

The ROTEX Solaris offers a flexible solar thermal system providing water heating and space heating backup, to be used for pressurised solar and drain-back applications. The Solaris solar panels convert almost all of the shortwave solar radiation into heat through their highly selective coating. The three solar panel sizes and different assenbly types mean there is flexibility in adapting to roof characteristics. Since all buildings are different, there are various installation options for fitting the ROTEX flat solar panels onto the roof.

Maximum water hygiene day after day

The ROTEX thermal stores were conceived in accordance with the latest thermal technology and water hygiene requirements. Its structure is fundamentally different from normal large volume hot water storage tanks. As a result of its design concept it delivers hygienically perfect hot water at any time. The actual heat is not stored in the domestic water itself, but in the storage tank water which is clearly separated from it. The optimum tank layering ensures that a supply of hot water is always available.

Innovative heat storage concept - Hygienic, flexible and future-oriented

All ROTEX products with the ECH2O label are characterized by a unique heat storage principle. Particularly space-saving, with the highest warm water comfort and open for additional heat sources.


ROTEX Solaris solar panels - flexible assembly

The Solaris solar panels convert almost all of the shortwave solar radiation into heat through their highly selective coating. The three different solar panel sizes mean there is flexibility in adapting to roof characteristics. Since all buildings are different, there are various installation options for fitting the ROTEX flat solar panels onto the roof. The solar panels can be fitted onto the tiles (on-roof ), into the roof (in-roof ) or also with a special substructure onto a flat roof.

Solar energy also to assist in heating

ROTEX Solaris uses solar energy for water heating and effectively supports heating. In all ROTEX solar thermal stores, and the gas condensing/solar combination (GCU compact) and heat pump/solar combination (HPSU compact) with a storage tank volume of 500 litres, solar heating support has also been integrated ready for connection, alongside the solar hot water generation. If the solar heat is not consumed immediately, the ROTEX solar thermal store can store large volumes of solar heat and it is possible to use the heat for hot water or heating hours later or even the next day.

Monthly energy consumption of an average family house

The diagram shows the monthly energy consumption of an average single-family house. The gray / yellow bar shows a system with the ROTEX A2 oil condensing boiler with 4 solar collectors for hot water generation and solar heating.

white = old system, grey = condensing boiler, yellow = solar energy use

Structure and function

The perfect store for use with solar – the right temperature at every level

Solar collectors work more effectively the colder the water flowing through them. In solar thermal systems, it‘s important for the thermal store to achieve the widest possible thermal stratification. With the ROTEX thermal store, cool fresh water is fed into the corrugated pipe heat exchanger at the lowest point in the store. From here it travels upwards and is heated employing the instantaneous water heater principle. This ensures maximum cooling in the lower part of the store, from which the collectors are supplied with water. The degree of thermal stratification this creates in the ROTEX thermal store significantly increases the benefit to be gained from the solar thermal system as a whole.

ROTEX Solaris: 2 possibilities - always the first choice

ROTEX Solaris is available in two different variants, that meet all structural conditions and individual requirements.

1. The pressurised solar system (Solaris-P)
The pressurised solar system impresses with its simple installation and is suitable for all applications and buildings. It operates efficiently and safely at any desired length of pipes and feed height. The well-engineered structure of the ROTEX solar thermal store means that an additional plate heat exchanger is not required. A bivalency heat exchanger for pressurised solar or other heat sources is already incorporated. That makes the system simple and flexible.

2. the direct Drain-Back system (Solaris-DB)
If the constructional conditions permit, we recommend the unpressurised and direct Drain-Back system. The water in the store is supplied directly and without heat exchanger to the solar panels, heated and then stratified into the store. This considerably increases the efficiency of the solar collectors and the entire utilisation of the installation. Since the system is unpressurised, components which would otherwise be required are not necessary, such as the expansion tank, pressure relief valve, pressure gauge and heat exchanger. The Solaris solar panels are only filled if there is enough heat from the sun and if the thermal store can absorb heat. The fully-automatic control system controls the system independently to provide optimum utilisation of the solar energy. If the sunshine is insufficient, or if the solar thermal store does not need any more heat, the feed pump switches off and the entire solar system drains into the thermal store. The addition of antifreeze agents is not required since the panel surface is not filled with water when the system is not operating. This is a further plus from the environmental perspective. The principle functions only if the connection pipes in the building and on the roof are installed with a constant gradient. If this is not possible, the pressurised solar system is the optimum alternative.

Energy efficiency class

Energy efficiency label for heating systems – safe in the knowledge it‘s ROTEX

Haus Ölkessel mit Heizöltank und SolaranlageAll ROTEX products are tested and meet the criteria of the Ecodesign Directive. For both individual products and packaged solutions, energy labels are a reliable indicator of the precise efficiency class. Perfectly matched in terms of their individual components, our complete systems provide both maximum convenience and the highest safety standards. 

The combination with a thermal solar system is the most effective way to improve the efficiency class of the entire system.


Example energy efficiency classes for the A2 oil condensing boiler as stand alone product and in combination with a solar system

Information about the energy efficiency labels

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