Vaughn's solar storage line (the SS Series) is engineered specifically for solar thermal water heating systems. Solar storage tanks have unique requirements vs standard indirect tanks: stratification preservation, multiple temperature sensors at different tank heights, dedicated solar-loop heat exchanger, and electric backup capability for solar-deficient periods.
Solar-specific tank design
An SS tank typically has two heat sources: the solar collector loop (heat exchanger near the bottom of the tank where cold water settles) and an electric backup element in the upper third of the tank. This allows the solar collectors to charge the entire tank when sun is available, while the backup element heats only the upper portion as needed. Stratification preservation is critical — well-stratified tanks deliver maximum solar capture by allowing the bottom of the tank to remain cold for collector inlet temperatures.
Sensor placement
SS tanks have multiple sensor wells along the tank height: bottom (solar return temperature), middle (overall tank temperature), and upper (backup element control). The differential controller monitoring collector temp vs tank bottom temp decides when to run the circulator pump. Proper sensor placement is critical — misconfigured sensors cause cycling, overheating, or solar capture inefficiency.
SS-Series sizing
Vaughn SS tanks are available in 80, 100, and 120-gallon capacities. For solar DHW, oversize the tank vs straight DHW demand — typical sizing is 1.5–2x daily hot water use to capture peak solar production. An 80-gallon SS handles a 2–3 person residence; 120-gallon for 4–5 person.
Closed-loop vs open-loop systems
Closed-loop solar systems use propylene glycol antifreeze in the collector loop, isolated from potable water by the heat exchanger. Open-loop systems circulate potable water directly through the collectors — simpler but only suitable in non-freezing climates. SS tanks support both configurations; the heat exchanger coil is designed for either water or glycol service.
Backup element configuration
The backup element is typically 4500W or 5500W 240V residential element. It runs only when solar input is insufficient to maintain setpoint temperature in the upper tank zone. Properly configured controllers minimize backup element runtime — typical solar-active homes use the backup 10–25% of total water heating hours, with solar handling the rest.
Lifetime stainless construction
Like all Vaughn tanks, the SS-Series uses 316L stainless throughout and carries lifetime warranty against tank failure. For solar applications where tanks experience repeated thermal cycling and (in open-loop) potentially aggressive water chemistry, stainless is the appropriate choice — glass-lined tanks fail faster under solar duty than standard residential service.
Pairing with collector brands
SS tanks work with collectors from any major manufacturer: Heliodyne Gobi, SunEarth Empire, Caleffi, Apricus, Rheem Solpak, etc. The tank doesn't impose brand restrictions; the controller and circulator/loop hardware match collector spec.