What does the power factor reveal?

In data centres, the power factor (PF) refers to the ratio between the active power and the total power(apparent power). It indicates how
effectively electrical energy is used.

The apparent power indicates the total electrical power in the system. This also includes reactive power. The active power shows the actual, usable power. The apparent power is therefore a combined representation of the active and reactive power that is required to provide and maintain the electrical system.

The active power and the apparent power are in phase when the power factor is 1.0 or 100 per cent. This indicates optimal use of the electrical energy. However, if the power factor is less than 1, energy is lost in the system because it is not used effectively.

Data centres try to achieve a high power factor in order to maximise energy efficiency. A low power factor may be due to the fact that electrical systems that support energy supply and distribution are not working optimally.

If the cause is found, the power factor in the data centre can be improved and thus energy losses can be reduced. This can be achieved by using power factor correction equipment or optimising the power supply.

How is it different from the PUE?

The power usage effectiveness (PUE) is an indicator that can quantify the energy efficiency of a data centre. The PUE indicates how much energy is fed into a data centre in total, and how much of it is consumed by the IT equipment. 

The PUE therefore includes all values including the IT equipment and the auxiliary systems as well as cooling and lighting. Since the supporting systems require less energy than the IT equipment, a low PUE value indicates higher energy efficiency.

The power factor and the PUE value are indicators of energy efficiency, but they measure different things. While the PUE takes into account the efficiency of the total energy consumption of the data centre, the power factor only pertains to the use of purely electrical energy.

What are the advantages of the power factor?

The power factor is very important for a data centre. You too can derive many benefits from it. These are some of the
added values that a high PF value entails:

Energy efficiency: A low power factor indicates that part of the electrical energy is not being used efficiently. This leads to additional electrical losses in the data centre that are avoidable. These losses can be reduced and energy efficiency increased by improving the power factor.

Cost savings: Because energy suppliers often charge extra for customers with a low power factor, a low value can lead to higher electricity costs. Data centres can reduce their electricity bills and save costs by optimising power factors.

Load on the electrical systems: Since more current must flow to provide the same amount of active power, a low power factor leads to a higher load on the electrical systems. This can lead to overloads and damage to the electrical IT infrastructure of the data centre. A high PF value improves the reliability of the power supply system and reduces the load.

Environmental impact: The energy consumption of a data centre can be reduced by improving the power factor. This reduces the environmental impact, especially the emission of CO2. It also simultaneously contributes to the sustainability of the data centre.

It is crucial to monitor the power factor and make improvements where necessary. This may include using more efficient equipment, optimising the power supply or using PF correction equipment.

Even now, there are monitoring systems that can monitor the power factor in real time. Smart PDUs, for example, are advanced energy supply systems that make this possible. You can monitor the PF values and take measures to improve the power factor if necessary.