The SOLARdrive Pre-heating System Wagner& Co Economic solution for existing buildings Fig. 1 The SOLARdrive pre-heating system The SOLARdrive pre-heating system supports conventional boiler based water heating and is equally suited for solar-thermal expansion of existing hot water systems and for new installations. Features at a glance: Optimal dimensioning through modular design (storage tank, drawing capacity) ● Easy to combine with existing systems ● 100 % water hygiene (according to DVGW 551, German professional gas and water association standards) ● High solar yield (good storage tank cooling) ● System additions for implementing space heating support ● Usable for systems with tapping rates of up to 200 liters per minute (e.g. for multi family dwellings up to 120 units) ●

Collector field Lower priority storage tank SV Priority storage tank P1 Vu1 M RATIO-H P Pre-heating unit RATIO-H P CIRCO DHW storage tank PHE P4 P2 RATIOdrive Oil or gas boiler Vu2 M 000 m³ Hot water P5 Re-circulation Membrane expansion vessel Cold water Fig. 2 Example of functional scheme with load priorities for two buffer storage tanks System Design a) Solar storage tank loading The buffer storage tanks are loaded by a pump in the primary solar circuit which transfers the heat absorbed by the collectors to the loading heat exchanger (figure 2). Capacity for large installations in low-flow...

Precondition for the choice of a SOLARdrive system is a consistent user tapping profile, as for example with multi-family homes, as well as a not too high solar fraction (approx. 30 % to 50 % related to the DHW demand without taking circulation losses into account). d) DHW re-circulation (fig. 3) Many multi-family dwellings have long DHW re-circulation pipes and times, requiring considerable stand-by energy to keep supplies ready for delivery. Especially during summer these heat losses can largely be recovered by solar energy. In connection with our SOLARdrive system, the solar heating of the...

influence for using the latent heat recovery is the temperature level of the heating installation. In large heating circuit volume flows (from pipes of about DN32) partial volumes are separated by means of their own small scale circulators, thus causing a defined volume flow to be passed through the solar buffer storage tanks (fig. 5). A switching of the complete heating circuit volume flow to the buffer storage tanks would deliver only short-term support while unfavorably mixing the strata of the water stored. M Sizing ● ● ● Oil or gas boiler For good economic outcomes, the solar installation...