Buffer tank with coil Wolf SPU-2-W 800 2483050

Integrated Heat Buffer for Hybrid Systems

A buffer tank with a working capacity of 780 liters (according to manufacturer data, based on a nominal 800 l) is a key component in modern heating installations, enabling effective separation of heat production from its consumption. Constructed from black steel and intended exclusively for closed-loop systems, this unit eliminates the need for internal anti-corrosion protection—a standard in oxygen-free systems. This design ensures high durability while maintaining lower operational costs.

The main advantage of this model is the built-in flat heat exchanger (coil) with a surface area of 2.4 m² and a volume of 15 liters. This configuration allows direct connection of solar collectors without the need for additional circulation pumps or complex intermediate circuits. In practice, this means excess solar energy can be efficiently stored in the lower sections of the tank and subsequently used to heat heating water or domestic hot water during peak hours or during nighttime cooling.

Mounting Flexibility and Thermal Insulation

High-quality thermal insulation directly translates into reduced heat losses and lower primary energy consumption. The tank is equipped with a 100 mm thick polyurethane foam layer, ensuring a ready-made heat loss indicator of approximately 2.59–2.89 kWh/24h (depending on measurement conditions). For the installer, the ability to remove the outer jacket along with the insulation before transport to the boiler room is crucial. This allows the unit, with an external diameter of 990 mm (including insulation), to be easily moved through standard doors approximately 80 cm wide and then reassembled on-site—a process that significantly simplifies logistics in existing buildings.

The tank design includes a wide range of connections, making it a universal component for various heat sources:

• 8 main connections with a diameter of 1½ inches allow flexible connection of the boiler (e.g., solid fuel), low-temperature source (heat pump), heating circuits, and domestic hot water circulation.
• 4 temperature sensor connections (½ inch) enable precise monitoring of thermal stratification inside the tank.
• Ventilation connection (1½ inches) and a dedicated inlet for the solar heat exchanger (1 inch) ensure system completeness without the need for additional adapters.

Application and Operating Conditions

The device is designed for operation in closed heating circuits in accordance with DIN 4753 and DIN 12828 standards. The maximum operating temperature for the secondary circuit is 95°C, while for the primary circuit (e.g., from a boiler or collector) it can reach up to 110°C, making it a safe solution even for solid fuel boilers operating with a large temperature margin. Working pressure varies: up to 3 bar on the heating water side and up to 10 bar on the heat source/exchanger side, providing a large safety margin when operating with heat pumps or condensing boilers.

A working capacity of 780 liters makes this tank an optimal buffer for single-family homes and small multi-family buildings. The solar heat exchanger surface area of 2.4 m² guarantees effective integration with medium-sized solar installations, while the 100 mm thick thermal insulation minimizes standby losses and contributes to real energy savings. It is worth noting the varied working pressures: the standard 3 bar on the central heating installation side, sufficient for most residential buildings, and the higher allowable pressure up to 10 bar on the heat source side—ensuring resistance to high operating parameters, e.g., in network boilers or heat pumps.

It should be remembered that this tank does not have an internal anti-corrosion coating. This is an intentional solution resulting from operation exclusively in closed water circuits devoid of oxygen. In case of use in open systems or where there is a risk of water aeration, additional protective measures or a different type of tank will be required. Installation should be carried out by a qualified person in accordance with the manufacturer's guidelines and applicable health and safety regulations and industry standards.

Thanks to its solid steel construction and precise heat exchanger manufacturing, this model proves effective not only as