Solar Accumulator Tanks

Radiator circuits are connected flow from the top of the tank and return to mid point. Underfloor heating circuits can be connected flow from the mid point, return to the bottom. Heating flow temperature can be controlled using a 3 way blending valve and regulator such as the Thermomatic K.

Systems incorporating both radiator and underfloor heating can be connected with flow from both the top and the mid point using a 4 way bi-valent blending valve controlled by a Thermomatic K or similar. This arrangement makes use of heat energy from the mid point of the tank when available.

Akvaterm’s Solar and Solar Plus range of tanks are designed to make solar energy available to both heating and DHW. If the top of the tank is not connected to an automatic boiler capable of meeting the heating demand consideration must be given to the control of the heating to prevent depletion of the heat reserve for DHW.

The AKVAir Solar is available from 300-2000 litres and is 3 bar pressure rated. The tank has 3 coils, one for solar input and two for domestic hot water (DHW).

The coils are permanently fitted and not removable as in the AKVA, AKVASAN and AKVANTTI tanks.

The tank is divided by a baffle plate with approximately 60% below and 40% above the baffle.

The solar coil and the pre-heat DHW coils are positioned vertically in the lower part of the tank. The solar coil is connected for downwards flow and the domestic water for upwards flow.

The secondary DHW coil is located above the baffle plate, for connection in series from the lower coil. A thermostatic mixing valve can be installed between the lower and upper DHW coils if desired to reduce flow through the top coil. A thermostatic mixing valve is required in all cases after the top DHW coil.

Automatic boilers, whether gas, oil, wood chip or wood pellet, are connected across the top and mid point of the tank. Batch fed boilers and stoves should be connected top and bottom to provide the full buffer volume of the tank.

AKVAir - Solar Accumulator Tank