Nearly 40% Reduction in Site Energy Consumption — Without New Equipment
At a technical site operated by a nationwide telecommunications provider, submetering revealed that the unusually high energy consumption was not caused by the core technology, but by the way the cooling system was operating.
As a result of the investigation, the site’s electricity consumption was reduced from 510 kWh per day to approximately 300 kWh per day.
No new air-conditioning equipment or other energy-efficiency investment was required.
The existing system simply needed to be configured and operated correctly.
The starting point
We were analysing the energy consumption of several sites operated by a nationwide telecommunications provider when one technical site stood out because its consumption was higher than that of comparable locations.
The main meter could show only that the site was using a large amount of electricity.
It could not show what was actually consuming that energy.
We therefore installed submeters on the main consumption groups.
What did we measure?
We measured separately:
the site’s total electricity consumption;
the consumption of the two air-conditioning units;
the 230 V input consumption of the 48 V power supply serving the telecommunications equipment.
Why was this necessary?
This allowed us to divide the site’s overall consumption into two fundamental components:
technology-related consumption and cooling energy demand.
This was the point at which it became clear that the proportion of energy consumed by the air-conditioning units was unreasonably high.
What did submetering reveal? image
The measurement data quickly showed that the air-conditioning units accounted for an unusually large share of the site’s total electricity consumption.
The units were operating almost continuously in compressor cooling mode.
This was particularly striking because the site was also equipped with free cooling.
When outdoor temperatures were suitable, there should therefore have been no need for the much more energy-intensive air-conditioning compressors to provide continuous cooling.
Based on the measurement data, we were able to focus the investigation specifically on the operation of the cooling system.
We found three problems
The investigation showed that the high consumption was not caused by a single fault.
1. The temperature sensor was installed in the wrong location.
The sensor controlling the air-conditioning system had been positioned directly above technical equipment that continuously generated heat.
As a result, the sensor measured a higher temperature than the actual room conditions and continuously generated a demand for cooling.
2. Free cooling had been disabled.
Although a lower-energy cooling option was already available, the system was not using it.
3. The target room temperature was set too low.
This further increased the operating time and energy consumption of the air-conditioning units.
What did we change?
We did not replace the air-conditioning units.
We did not install a new cooling system.
No energy-efficiency investment was required.
We made three changes:
relocated the temperature sensor to an appropriate position;
enabled the existing free-cooling function;
adjusted the target room temperature to an appropriate value.
We then measured the site’s electricity consumption again.
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The result: 510 → 300 kWh/day
The comparison was made using the same week in August 2021 and August 2022, under similar outdoor temperature conditions.
Before intervention:510 kWh/day
After intervention:300 kWh/day
Reduction:210 kWh/day
Reduction in total site electricity consumption:nearly 40%
All of this was achieved without installing any new equipment.
What does this case show?
High energy consumption does not necessarily mean that a piece of equipment is inefficient or needs to be replaced.
In this case, all the necessary equipment was already available.
The problem was that the system was not operating correctly and was not using the most energy-efficient cooling method already available.
The main meter alone could not have revealed this.
Submetering, however, made it visible where the energy was being used, allowing the cause of the high consumption to be identified precisely.
What is consuming energy at your site?
Your main meter shows how much energy you use.
Submetering can also show you where that energy is going.