The SOLARstore Pre-heating Storage System Wagner& Co Efficient solution for very high consumption Fig. 1 The SOLARstore pre-heating storage system The SOLARstore pre-heating storage system cobines the use of larger solar storage tanks with the demands on higher water hygiene in combination with highest tap rates. Features at a glance: Ideally suited for highest tap rates, e.g. in hospitals, hotels and commercial premises ● Easy to retrofit to existing systems ● 100 % water hygiene according to the standard set by the German Technical and Scientific Association for Gas and Water (DVGW) ● Proven concept from the solar heating program of the German government, Solarthermie 2000 ● High solar yield ● Unlimited supply reliability ● Optional system additions to support spatial heating ●

Collector field T1 P6 Oil or gas boiler Circuit Hot water P1 CIRCO M Pre-heating tank T7 Lower priority buffer tank M Priority buffer tanks P2 P4 Standby tank Ttw P3 M V4 T8 P5 Cold water Membrane expansion vessel Fig. 2 Example of functional scheme with prioritized loading of two buffer tanks System Design a) Solar storage tank loading The buffer tanks are loaded by a pump in the primary solar circuit which uses a frost resistant heat carrier to transport the heat absorbed by the collectors to the loading heat exchanger (Fig. 2). The typical design for large installations in low-flow operation...

pre-heating storage drops below the minimum difference, the pumps switch off again. To assure optimal cooling of the buffer storages, a two-prong regulator is used on the pre-heating tank. In line with regulation W551 of the German Technical and Scientific Association for Gas and Water (DVGW) the pre-heating section can be heated to 60 °C once daily if this is not achieved by solar irradiation. Preferably this disinfection is scheduled for evenings. This is also referred to as auxilliary heating for legionella prevention. e) Solar support of spatial heating – just a small step The SOLARstore...

Sizing ● ● ● ● To achieve a good economic outcome, the solar installation should be so dimensioned as to avoid production of unusable excess energy even in periods of lower hot water consumption. Energy production and storage are aimed at meeting daily needs, so that small, lower-cost tanks can be used. The 60 % to 70 % solar fractions commonly fitted for single-family homes are not aimed at for this application. A design oriented to an optimal cost-benefit ratio achieves solar fractions of 35 % to 50 % related to hot drinking water and re-circulation heating. The table below offers only a crude...