Our customer identified that this particular site was consuming excessive energy against their benchmark of an extensive number of similar sites. FEL Group were engaged and set an objective to reduce energy by the utilising recognised project initiatives to optimise energy performance.

FEL Group Energy Optimisation is an initiative to draw upon our extensive range of Energy Reduction Measures whilst remaining within the confines of the customers Design and Build standards. The corporate programme tackles the feasibility, design and delivery of energy performance improvements in existing technical facilities throughout the entire UK. The key stage programme is as follows:

  • Benchmarking
  • Improvement Scoping
  • Project and Programme Management
  • Project Delivery
  • Improvement Reporting

Recent trials suggest that the programme can improve overall site performance by 25%. These trials have shown there is reasonable room for improvement by way of cooling energy systems optimisation. Therefore, we can reduce the amount of energy we consume by dealing more efficiently with the network service by-product, heat.



Optimising energy performance


International television & telecommunications company


Leeds, West Yorkshire


2 weeks


3.3 years

Seasonal Site PUE Post Project


Predicted Annual Savings


Project outcomes

  • Benchmark savings identified 25% energy saving
  • Minimum spend for Maximum return – ROI’s
  • Mitigate and ensure that all initiatives meet stringent risk assessments
  • Life Cycle assessments
  • Refrigerant upgrade lowers energy & carbon footprint
  • Time Critical Implementation

Getting the balance right comes with our extensive knowledge and understanding of what the correct blend of multiple initiatives will cost, versus the target time period for a Return On Investment (ROI) – Minimum spend for Maximum return.

There are typically numerous challenges faced with implementing any optimisation programme.

Our process begins with surveying the whole facility, identifying the key rooms that can benefit from optimisation but then applying a logistical view against the potential impact of implementation to critical infrastructure.

The key step is to mitigate and ensure that all our initiatives meet stringent risk assessments that will prevent failure of any equipment. Maximising the balance between minimum spend for maximum return, customer timescales for delivering projects realising most of these are time critical, and finally taking a view on Life Cycle, noting the age and condition of the equipment to safeguard the ROI.

The main objective of this project was to reduce mechanical cooling running times and therefore maximise energy savings. The existing cooling on the site was in good condition, although utilisation was less than 50%. The site features 8no. Weatherite VMR15 fresh air DX AHUs, within the technical space providing N+1 cooling to the room.

A comprehensive matrix of Energy Performance Improvements was highlighted for this site.

The adopted measures to achieve our target were:

  • Temperature set points were modified in line with ASHRAE recommended standards to improve the Calibration and actual temperature set points were modified to the existing Outside Air Temperature sensors to improve the performance of the fresh air DX AHUs.
  • Replacing non-compliant refrigerants and optimising a performance enhancing upgrade the refrigerant type and the optimising the refrigerant volume in 2 of the existing units. The benefits were not only that these units became more economical on energy, but this refrigerant is more readily available, more efficient, sustainable, lower cost, and most importantly, a lower Global Warming Potential (GWP), thus directly improving the customers Carbon Footprint.
  • Room optimisation including rack and floor air blanking, minimising short cycling leakage and offering better air flow distribution around the room to the servers.
  • Introduce intelligent DX ‘hold off’ controls to 5 of the 8 fresh air DX AHUs. This reduced power consumption for the mechanical cooling function on the AHUs and maximised the direct free air cooling potential.
  • Installing EC fan upgrades to 3 of the primary existing AHUs benefited to a very high degree of improved efficiency. The smaller sized motor gave the same level of performance for less power consumption.

The existing site Power Usage Effectiveness (PUE) before the implementation of the programme was measured and calculated as 1.77

The seasonal PUE post project was completed became 1.65

Predicted savings for this project were £2,173/month.

Actual first month savings were £2,827/month. (30% higher than seasonal prediction)

The overall predicted savings for the first year is tracking at £24,037. (seasonal adjustment for Free Cooling potential taken into account)

This gives an ROI for the project of 3.3 years.