Case Study - NATS, Prestwick Centre

16.36

FINANCIAL SAVING

£6,753

CO2 SAVING

46,370 kg

EndoTherm was installed into a NATS air traffic control centre in Ayrshire, Scotland.

The Prestwick Centre in Ayrshire is NATS northern office. It is a 14,000 square meter mixed use
commercial building. The site is heated by air conditioned systems and fan coils which is powered by 5 x Ferroli 247.5kW boilers (combined rating of 1,237.5kW). The system was dosed with the closed system inhibitor (Chem Aqua 999).

Existing records of the system noted the combined system volume as being 14,000L needing 140L of EndoTherm. The site was also dosed with 30% Glycol which is commonly used as an anti-freeze.

 

Results

A methodology adopting CUSUM and regression analysis was agreed by Endo Enterprises (UK) Ltd and NATS.

The monthly values of usage (kWh) over heating degree days (HDD) for the previous 15 months was plotted to establish a relationship of the building before any change occurred. The on-site kitchen usage is sub-metered and was removed from the gas values.

The trend-line equation was confirmed as: y = 168.31x + 110143. See graph below.
Note: Degree Days were taken from the on-site EGPK: Prestwick Airport

 
NATS case study graph
 

Using the trend-line equation. The predicted usage was taken for each month and compared with the actual usage on site.

Month HDD Predicted Usage Actual Usage Difference CUSUM
Apr 2015 234 149,504 121,137 -28,366 -28,366
May 2015 182 140,757 107,933 -32,823 -61,189
Jun 2015 95 126,122 105,456 -20,666 -81,855
Jul 2015 64 120,908 105,945 -14,962 -96,817
Aug 2015 49 118,385 105,809 -12,576 -109,393
Sep 2015 108 128,309 82,663 -45,646 -155,039
Oct 2015 154 136,047 100,139 -35,908 -190,947
Nov 2015 208 145,130 136,920 -8,210 -199,157
Dec 2015 224 147,822 126,511 -21,310 -220,467
Jan 2016 314 162,960 158,316 -4,644 -225,111

Over the 10 months the cumulative saving was 225,111kWh. At 3p/kWh this is a total saving of £6,753 and a total carbon saving of 46,370kg of CO2. Consideration is now being given to the other NATS sites around the UK.

“In April 2015 NATS Facility Management introduced EndoTherm and Glycol into its Prestwick Centre heating system. The results have been impressive, 16% reduction in energy and a CO2 reduction of 46 tonnes.”

Facilities Team

NATS