Buffer tank with coil Wolf SPU-2-W 1000 2483051

Balancing System Operation and Energy Savings

A 1000-liter buffer tank (actual working capacity 960 l) is a key element for the stable operation of modern heating systems. Its primary function is to store excess heat produced by the source, such as a solid fuel boiler, heat pump, or solar collectors, and release it into the heating circuit when energy demand is lower than production. This prevents the boiler from operating in a continuous short-cycling mode, significantly extending the lifespan of its components and improving the overall system efficiency. When used with solid fuel boilers, the buffer allows for burning a full fuel charge at maximum efficiency, with excess energy simply "stored" for later use instead of being lost through the chimney.

Heat Retention and Installation Flexibility

The thermal insulation, made of 100 mm thick polyurethane foam, effectively minimizes heat losses, with a loss coefficient of only about 3.02 kWh/24h. This means that the energy stored in the tank remains available for many hours without the need to restart the heat source. For installers, the design allows for the removal of the outer jacket along with the insulation before transport to the technical room. This enables a unit with external dimensions (including insulation) of approximately 2135 mm in height and 990 mm in diameter to be easily carried through standard doors with a width of about 80-90 cm and then assembled in the final location. The tank itself is made of black steel and is intended exclusively for closed water installations free of oxygen; the lack of internal anti-corrosion protection is due to the fact that steel is sufficiently durable under such conditions.

Solar Coil and Universal Connections

The SPU-2-W version features a built-in coil (heat exchanger) made of smooth steel pipes with a heat exchange surface of 3 m² and a capacity of 19 liters. This allows for the connection of an additional heat source—most commonly solar collectors—which can heat the water in the tank independently of the main boiler. Such a setup enables the utilization of free solar energy even when the boiler is switched off or operating at low load. The tank is equipped with a comprehensive connection list:

• 8 threaded openings with a diameter of 1½" intended for main hydraulic circuits (boiler supply and return, radiator/floor heating circuit).
• 4 openings with a diameter of ½" dedicated to temperature sensors or additional accessories.
• Possibility to mount a thermometer and an automatic air vent directly into the tank wall.

The device operates safely at a maximum working pressure of up to 10 bar (primary and secondary sides) and temperatures up to 110°C on the primary side and 95°C on the secondary side, making it compatible even with condensing boilers operating at high parameters or high thermal output solar systems. The unit weighs approximately 149 kg, which must be taken into account when planning the foundation or mounting surface in the technical room.

Using this type of buffer is an investment in the stability of the heating system, which translates into lower operating costs through optimization of the heat source operation, as well as the possibility of easily expanding the installation with renewable energy sources in the future.