Fast accesses

11. – 15.3.2019 (Monday – Friday), Frankfurt am Main

Sustainable systems for domestic hot water heating

Using renewable energies for domestic hot water heating

Hintergrundbild bdew

Dwindling reserves of fossil fuels and society’s focus on greater sustainability have paved the way for renewable energy sources such as solar energy. This, among other energy sources, can be used for producing hot water in our own homes. However, fluctuating temperatures in the hot water tank can put domestic water hygiene at risk.

"Domestic hot water systems powered by solar energy present a particular challenge because the temperature of the hot water can fall below what is required, owing to seasonal variations and ambient weather conditions", says Wolfgang Burchard, Director of the VDMA’s Association of Valve Manufacturers. According to the DVGW worksheet W 551, in large systems the temperature of the hot water drawn from domestic hot water heaters must be kept at 60° C. Otherwise legionella bacteria can multiply and put domestic water hygiene at risk. Not all domestic water heating systems, therefore, are suitable for use with solar thermal installations.

'Water storage' systems are commonly used to supply hot water to buildings. They heat up the water and store it till it’s drawn off. This can lead to long periods of stagnation. 'Instantaneous' domestic water heaters only heat the water when the tap is turned on, and so provide a more hygienic solution. What is more, systems of this kind can be connected to renewable energy sources such as solar panels. 'Storage charging' systems constitute a combination of both models but, like storage systems, are not recommended for connecting up to solar panels. In principle, increasing use of renewable energy sources promotes sustainable use of resources, but domestic water hygiene must not be jeopardised by the use of solar energy. As Burchard points out, "Domestic water hygiene must always have top priority". Constant monitoring to check that the hot water is at the temperature required and regular maintenance of the domestic water heater are essential.

  • off icon facebook

    2 Klicks für mehr Datenschutz:
    Erst wenn Sie hier klicken, wird der Button aktiv und Sie können Ihre Empfehlung an Facebook senden. Schon beim Aktivieren werden Daten an Facebook übertragen.

  • off icon twitter

    2 Klicks für mehr Datenschutz:
    Erst wenn Sie hier klicken, wird der Button aktiv und Sie können Ihre Empfehlung an Twitter senden. Schon beim Aktivieren werden Daten an Twitter übertragen.

  • off icon google plus

    2 Klicks für mehr Datenschutz:
    Erst wenn Sie hier klicken, wird der Button aktiv und Sie können Ihre Empfehlung an Google+ senden. Schon beim Aktivieren werden Daten an Google+ übertragen.