The SOLARfresh System Wagner& Co Domestic water hygiene for multi-family houses Fig. 1 The SOLARfresh system The SOLARfresh system combines the possibility of using larger solar storage tanks with the demands of higher water hygiene in multi-family dwellings, sports facilities and commercial premises without compromising supply security and ease of operation. Features at a glance: Optimal sizing by modular options (storage tanks, tapping volume) ● Compact and especially suitable for new installations ● 100 % water hygiene (according to DVGW 551, German professional gas and water association standards) ● High solar yield (good cooling of storage tanks) ● Very good cost-benefit ratio ● RATIOfresh return switching for optimal performance with high circuit volumes ● Simple system additions for space heating support ● Optimal suitability for solar systems with tapping rates up to 160 l/min (e.g. for sport venues, hotels and multi family houses with up to 100 apartments) ●

Collector field Solar controller P1 Lower priority storage tank CIRCO Priority storage tank SV HK P4 Freshwater unit M1 RATIO-H P P3 RATIO-H P PHE Oil or gas boiler P2 RATIOfresh Vu1 Vu2 M Back flow switchover P5 Circuit Vr Cold water Hot water Fig. 2 Example of functional scheme with load priorities for two buffer storage tanks System Design a) Solar loading of storage tank Buffer storage tanks are loaded by a pump in the primary solar circuit which transports the heat absorbed by the collectors to the loading heat exchanger by a frost-resistant heat carrier (fig. 2). The typical design for...

RATIOfresh 80 mbar 10 mbar Circuit Fig. 3 Cascade connection of two RATIOfresh freshwater units M Oil or gas boiler M e) Solar support of spatial heating – just a small step The SOLARfresh system uses solar buffer storage tanks filled with heating water and already connected with the conventional auxilliary heating of the stand-by volume. That makes it very easy to add solar support to spatial heating. Recommended for projects in small buildings is boosting the return temperature of the heating circuit by switching to the buffer tank through a three-way diverter valve, provided that sufficient...

circulators, which causes a defined volume stream to be run through the solar buffer tanks (fig. 5). Switching the whole heating circuit volume to the buffers would produce only a short-term support while unfavorably mixing up the entire buffer content. Heating domestic water [%] 100 80 60 40 20 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Time span 01.01- 31.12. Solar fraction, tot. 46% Support for DHW and space heating [%] [kWh] 100 2,500 80 2,000 60 1,500 40 1,000 20 500 0 0 Sizing ● ● ● ● To achieve a good economic outcome the solar installation should be so dimensioned as to avoid production...