Solarthermie² - Warm hotel pools in the winter season 

& solar drinking water heating in the summer season -  for sunny regions!

The Problem

  • Holiday hotels invest large sums in the construction of attractive pools and sophisticated water slides.
  • Pools and slides are only used for a few months during the peak seasons. Low water temperatures make it impossible to enjoy such facilities during the other seasonal periods.


  • The state of the art for about 30 years in Central Europe, largely unknown in southern regions: Solar absorbers for heating large amounts of water.
  • A pleasant side effect in sunny regions: During the summer months, you can use the energy generated in the absorber to heat drinking water.

  Dipl.-Met. Bernhard Weyres-Borchert, President German Solar Energy Society (DGS), Board of Directors International Solar Energy Society,SolarZentrum Hamburg: 
  "Solar swimming pool heating with unglazed absorbers is, economically speaking, the most interesting application in the area of solar-thermal utilisation. For hotels in Southern Europe, the question of how to exploit solar energy often arises in the summer months, since the swimming pool water is already heated sufficiently by the air temperature and direct solar radiation alone. The Solarthermie² system solves this problem with the novel concept of utilising the summer excess for drinking water heating. This kills two birds with one stone: extending the operating period of the swimming pool in the winter term and cost-effective drinking water heating during the summer months. It only now remains for this concept to become a model for hotels in southern holiday regions."

Solar absorber systems for effective and efficient pool and drinking water heating

Solar absorbers made of EPDM

  • A nearly indestructible material made of EPDM (a product used in the automotive industry among others)
  • Service life > 25 years
  • Cost-effective and almost completely maintenance-free
  • Short amortisation period
  • Resistant against UV radiation, ozone, frost and chemicals
  • Temperature-resistant from – 50°C to + 150°C
  • Environmentally friendly: You make use of clean energy, reduce the emission of pollutants and have a positive effect on your image


Berlin, Dipl. Ing. Michael Thoma, Energy commissioner of the Berliner Bäderbetriebe:

  "For the Berlin baths, solar absorber systems are a practical solution for reducing operating costs and meeting climate protection goals."

Absorber systems have already been installed in well over 2,000 municipal pools in D-A-CH!


Dipl. Ing. (FH) Ralf Orths, Wagner Solar GmbH: 

  "Solar absorber pool hearing systems are not promoted financially in Germany because of the relatively short amortisation period.“

Pool heating systems in Central Europe with a focus             on D-A-CH

An economical and effective method. The bathing season can be extended significantly.

Combination of 1 and 4.

A practical solution when constant temperatures are required, e.g. for training and competition pools!


Pool heating systems for hotels in southern regions

The easiest and most economical method.

High temperature fluctuations and short times of use, depending on the region.

The most expensive and environmentally harmful method.


Guarantees constant water temperatures, causes high energy costs and high CO2 emissions!


The solar revolution - Solarthermie²


Prof. Dr. Klaus Vajen, University of Kassel, Institute of Thermal Energy Technology, Germany

  "The innovative solar system developed by the Wagner company for use in Mediterranean hotel facilities is technically sophisticated and has great potential for lowering energy costs." 

The advantages

  • You offer your customers added value
  • You increase your seasonal capacity
  • You win over new target groups
  • You create unique selling points
  • You reduce your energy costs considerably
  • You can remain calm amid rising energy costs
  • You reduce CO2 emissions substantially
  • You make a name for yourself ecologically

The solarthermics system of the future for pool and drinking water heating in sunny regions:

The technology

  • A hotel‘s existing heating technology is supplemented by the solar absorber, the preheating reservoir and the control technology.
  • When the pre-set pool water temperature has been reached, valve 1 directs the energy generated in the absorber to the preheating reservoir.
  • The cold water in the preheating reservoir can be heated to 45/50°C or 55°C with solar energy depending on the intensity of the sun.
  • The existing heating system only needs to compensate the difference to reach the required 60°C.

Simulation calculations

The data you submit become the parameters to determine the following values, amongst others:


  • Savings in fossil fuels in litres of oil or in m3 of gas
  • Prevented CO2 emissions in kg or tonnes
  • Attainable average pool temperature per period in °C
  • Energy supply for drinking water heating
  • Solar fraction of water heating
  • Volume of preheating reservoir required
  • System efficiency in %

Graphic displays:

  • Share of energy consumption accounted for by solar energy
  • Temperature profile of the pool water
  • System efficiency for pool and drinking water heating
  • Amortisation pattern
  • Energy balance schematic

The right partner, little by little

With unique component designs and customised construction processes, we provide solutions for all phases of implementation:

  • Consulting
  • Dataacquisition by questionnaire
  • Cost estimate
  • On-site testing
  • Proposal
  • Construction
  • Service and monitoring

SPENSO Partner:

ISS GmbH, 

Ice & Solar Systems 


Wagner Solar GmbH

Questionnaire Solarthermie²

For a quote: Please fill in the details of your object.
Download Questionnaire Solarthermie² - english version (PDF)
Object data.pdf
Adobe Acrobat Dokument 1.5 MB