Whether of not a buffertank?

There are (many) people who are not familiar with a heat pump and when purchasing or advising them often ask: “I cannot install a buffer tank. It takes so much space and money……”

What role does the buffer tank actually play in the system?

This is the difference between a commercial installation (without buffer tank) and a technical installation (with buffer tank).

The buffer (water) tank is a necessary part of the central heating system:

• increasing the water capacity (of the system that is too small);
• storage of heat and cold;
• prevention of fluctuations in the water flow (malfunctions in the heat pump);
• less frequent start-up of the heat pump (shortens lifespan).

With the ultimate goal of extending the lifespan of the equipment and saving energy and electricity.

1: Reduce the frequent start of the heat pump

Since the circulating water in the loop is limited, the heat pump will reach the target temperature in a very short time. The heat pump stops working and in a very short time the water temperature reaches the starting state of the heat pump and the heat pump starts again, so the frequent starting will significantly reduce the service life of the heat pump and significantly increase the waste of electricity. The buffer tank effectively solves this problem. That is why the heat pump system not only needs a buffer tank. The capacity of the buffer tank is also important. The rule of thumb is 20 x the heat pump’s capacity with a minimum of 200L.

2: Efficient defrosting, the defrosting time is short

When used in severe winter, especially between -3° C and 5° C, the white frost on the heat pump is clearly visible and the effect of defrosting on the indoor temperature is a disadvantage. Because the unit needs to consume heat in the pipeline during reverse operation (cooling), if the water volume of the water system is small, the defrosting time will increase, and the water temperature in the pipeline will be low and the defrosting effect will be poor.

In this way, if the buffer tank is present during the defrosting process, and there is a certain temperature in the buffer tank, defrosting can be completed in a short time, and the heat consumption is also small, thus avoiding temperature fluctuations (in the home).

3: Fully automatic venting

When the system is running, the water temperature will repeatedly produce bubbles. If these air bubbles are not discharged in time, it will cause system instability, resulting in frequent failure of the heat pump and even damage to the pump and other components.

The water pipe connection is directed up and down, so that the air bubbles in the water accumulate in the upper space of the buffer tank. The pressure in the closed system will automatically ensure that the air bubbles are discharged through the upper air vent. This solution will not only protect the pump impeller, but also guarantee the operation of the heat pump.

In addition, the rapid venting can also reduce commissioning time and difficulty. If there is air in the system, the flow switch often gives an alarm and the heat pump is also equipped with high-voltage protection, which significantly extends the troubleshooting time. If the buffer tank is installed, not only the heat exchange of the system is faster, but also the failure rate can be reduced, greatly shortening the troubleshooting time.

4: Protect the heat pump from the end

The buffer tank also plays an important role in the overall system. Namely the hydraulic balance between heating and delivery. The aim is to separate the various circulation pipes in the heating system from the heat pump so that the various circulation pipes do not (negatively) influence each other.

We call this a secondary system: the heat pump and the buffer tank are an independent circulation system. The buffer tank and the delivery system in the home are an independent circulation system. The heat pump and the delivery system are not directly connected to each other. The heat pump only heats the buffer tank, stops or starts when the set temperature is reached and is not affected at the end. In this way the stability of the heat pump is significantly increased. Because the heat pump has a minimum required water flow value, if the water flow is lower than the minimum value, the system will report high pressure in heating, while in cooling it reports antifreeze.

After reading the explanation, do you have any questions or would you like advice for your system? Please contact us for further advice on this.