Modern heat pump installations provide air conditioning (heating/cooling) in summer. However, the PU foam used to permanently seal commercially available buffer tanks is not diffusion-proof. The connections are not sealed in an airtight manner. Some flanges are also not insulated. Such designs were conceived only for heating purposes. Using them as a cold buffer may result in damages over the long term. Water condensing on the exterior of the tank leads to corrosion. This causes the tank to rust from the outside inwards.

Cooling/heating storage tanks with a time delay need to be of the right size and insulated specifically for this purpose.

Depending on the specific usage scenario, diffusion-proof thermal insulation for cold will need to be installed in addition to insulation for heat. The large variation in the installation scenarios of the tank may also contribute to the temperature falling below the dew point, such as installation in niches without air circulation, high temperatures and humidity due to the use of electric clothes dryers in the room they are installed in, or a low air circulation due to good insulation.

When does a cold buffer tank need to be installed? 

If cooling is done via the floor, the temperature in the buffer generally does not fall below 18°C, as this would be below the dew point, and water will condense on the floor. For a buffer tank in a ventilated room with a normal relative humidity, this generally does not occur. We recommend that the connections at the sockets be double-sealed, and if there is a flange installed, that cold insulation be glued over the cover.

If cooling is done via convector or ventilation devices, the buffer temperature may fall to 8 – 10°C. In this case, it is recommended that the buffer tank be equipped with cold insulation (vapor barrier).

hpa cold buffer tank

We have adapted our PU series for this usage scenario and insulated it accordingly. This reduces the heat loss when it is being operated for heating purposes, and also restricts the formation of condensed water.

Cold buffer tank

Schematic diagram of insulation for heating/cooling

Schematic diagram

Delivery time: 4 weeks

For cooling systems below 8°C, the specifications of the buffer will need to be calculated accordingly and insulated on-site.