Storage of Renewable energies

The storage of energy plays a key role in the use of renewable energy nowadays. High quality components and an accurate design secure a reliable operation without giving up modern convenience. Whether an electric or thermal storage is more suitable for you depends on your needs and your conditions onsite. You will get a concerted solution with optimum results!

Battery Storage Systems for solar energy

Battery storage systems are getting more and more into the limelight. The first economical useful systems of different manufacturers are on the market and already installed. The systems differ not only in their different battery technology but also in their connection to the photovoltaic system.  With the application of a storage system you can increase significantly the amount of your own used electricity. To design a battery storage system for your need some important requirements have to be analysed to ensure the best solution for your application. We are happily advise you with all our knowledge and experience and identify the best storage system for you.

Fuel Cells

Fuel cells are used to generate electricity from hydrogen. There are different kinds of fuel cells for different application areas. The difference between the cell types lays in the electrolytes and the used fuel gas. An advantage of a fuel cell is the generation of electrical power without mechanical parts and emissions. Only water arises. The storage of energy in form of hydrogen is only then ecologically worthwhile if the hydrogen is generated by renewable energies and available in excess. The water itself which is used to generate hydrogen abounds on our earth. At the moment the storage and transport of mineral oil and natural gas can be achieved in a simpler way but well-known institutes and automobile manufacturers research intensively to find a solution to this challenge shortly. Hydrogen can be saved in liquid form (in extra isolated tanks) and in gas form (huge amounts in subsurface salt and rock caverns, small amounts in compressed gas cylinders) as well as in chemically bound state (Metal Hydride Storage). Prototypes of passenger cars, busses and vans as well as the first fuel cell heating systems are already used.

Ice Storage 

In combination with a Brine/Water-Heat Pump the ice storage uses the energy in the water during the transition to ice. The storage system is entrenched into the ground near-surface so that the lower end is approx. 4 meters under the surface. To the top it is covered with some soil.  Because the low temperature level is not sufficient for a direct use of heating support and warm water generation the thermal energy is extracted by a brine/water-heat pump. Everytine the water in the storage system cools down to 0 °C it starts to freeze. During the freezing latent heat is released. Eventually the storage system has to be recharged (regenerated) in which corresponding heat quantity has to be applied to melt the ice (e.g. with the help of a solar thermal system, the ambient air through an air heat exchanger or the waste heat of a ventilation system). The additional energy gain from this phase transformation equates to 100 liter of heating oil with an ice storage content of approx. 10 m³. During summer time the ice storage system can be used to naturally cool down the rooms. Therefor the system is completely frozen at the end of the heating period due to the disruption of the regeneration of the storage system by the heat source management. The generated ice can be used as a cold source.

Water Storage

The variety of warm water storage system is huge. Main areas of application are drinking water reservoirs and buffer storage for heating. Warm water storage systems can be heated in different ways:   

  • with an internal heat source (e.g. electric heating rod)
  • with an heat exchanger (e.g. helical tube in the storage system which can be connected to a solar system or a boiler) 
  • through the supply pf hot water which was heated externally (e.g. buffer storage with outside located plate heat exchanger) 

Warm water systems with warm water storage and the single distribution pipelines are technically very demanding. Warm water storage systems should not be designed too big but also not to small. Bigger systems have to be designed by an expert to guarentee the compliance with the "Technical regulations for drinking water systems". Also building norms and building laws of the federal states in regards to noise protection, fire protection and reliable operation as well as the numerous DIN EN norms and guidelines have to be considered. 

Paraffin Storage

A paraffin storage system consists of multiple approx. 200 cm long and 20 cm thick plastic pipes. Around these plastic pipes a thermally insulated corpus is build. The interspaces are isolated with filling material, e.g. gravel. The pipes itself contain paraffin. Through the paraffin run the heat exchanger of the solar system as well as pipelines for the heater circuit and the raw water. The space requirements of a paraffin storage system is on third lesser than for a water storage system. An adaption to the available space is possible in some circumstances. That's why a paraffin storage system can be also installed at unfavourable housing conditions. The storage capacity of a paraffin storage system is up to four times higher than of a water storage system. Also the long term storage capacity is significantly higher that of other storage system. During the heat supply (charging) the solid paraffin is melting inside the tubes. Because of this phase transformation a temperature of up to max. 85°C is stored. Is cold water piped through the tubes the paraffin solidifies again. The discharge takes place due to the solidifying whereat the storage medium releases the before absorped heat quantity as solidification heat to the ambiance.


Do you need help to choose the right storage technology for your individual requirements? Contact us and get a comprehensive consulting.