Case study - King's College London

Six-figure sum saved at King's College London

We are delighted to be able to announce results from our first case study. Since Demand Logic was installed at King's College London, savings worth around £390,000 have been identified.

Carbon saving 2500 tonnes per year*
Money saving £390,000 per year*
Project start date January 2013
Major plant items tracked 554
(includes boilers, chillers, pumps, air-handling units)
Data points In excess of 100,000
(includes sensors and terminal units)
Biggest source of savings Run time of major plant

* Indicative savings based on changes in plant behaviour. See below.

"The Demand Logic web system allows us to see at a glance where problems are likely to be. Without this, it's like trying to find a needle in a haystack"

Ian Armitage, Campus Operations Manager, King's College London

King's College London has been using the Demand Logic energy efficiency web platform since January 2013. The use of the platform is the latest in a series of leadership projects conducted by the college to reduce carbon emissions, for which the College has won numerous awards [1].

This latest initiative covers three campuses: Guy's, Denmark Hill and the Strand. Approximately 100 buildings ranging considerably in size and usage pattern were involved in the project.

The purpose of the Demand Logic platform is to identify energy saving opportunities in the heating, cooling and ventilation systems which are extremely hard to pinpoint in large, complex buildings. The system works by analysing data generated by the building control systems.

Savings

The project found that in the main, the College's facilities were running very efficiently thanks to determined efforts and successive energy efficiency drives. There are, however, many issues that can arise which cannot be easily identified by traditional energy management systems. This is why Demand Logic was chosen as a way to discover hard-to-find savings.

The project (still in progress as of Sept 2013) has so far unearthed 47 specific energy-saving opportunities. 38 of these have already been acted upon. Overall it is estimated the project identified savings worth approximately £390,000 per year. (NB: this is an indicative savings figure based on changes in plant behaviour as monitored by the Demand Logic system. It is not based on meter readings.) [2]

The indicative annual carbon saving is estimated at 2500 tonnes [3].

The College's annual energy spend is approximately £5m.

What kind of problems were uncovered?

The different energy problems identified by the system were highly diverse. In one case, boilers were rapidly cycling on and off because they did not have enough load. In another, several conflicting "set points" (desired temperature settings) had been applied to the same open plan office, causing both heating and cooling of the same space.

In a particularly notable case, having uncovered a large chiller running all day in the middle of winter, the system then found a single office that was causing the problem. This single room was being heated by a personal electric heater which was fighting the centralised cooling plant. (The main plant was trying to cool the space, and the electric heater was trying to heat it). This discovery was possible because the Demand Logic system monitors each of many hundreds of ceiling-mounted air-conditioning outlets in the building, and was able to identify the one that was demanding the most from the central plant.

Importance of the in-house team

In order to ensure that opportunities raised by the Demand Logic platform were acted upon, the College brought together a team of key staff, comprising facilities managers and other personnel from each campus. This group were able to share with each other live and historical visualisations of the heating and cooling systems, for example showing when large items of plant, like chillers or ventilation plant, were running.

This team also uses the Demand Logic system to ensure that measures they introduce don't "slip back" a common problem in energy efficiency. Slip-back can be caused, for example, by plant being put into manual control for urgent reasons and then remaining in manual without being noticed.

Ian Armitage, Campus Operations Manager at King's College London, said:

"I believe that good control systems in buildings are the key to saving energy without compromising user comfort. Demand Logic has helped the College to find a host of issues about how our heating and cooling plant is controlled, leading to significant savings which we are using to fund investment in our student facing facilities. Our campus buildings generate a vast amount of data, but accessing and analysing this is a real challenge. The Demand Logic web system allows us to see at a glance where problems are likely to be. Without this, it's like trying to find a needle in a haystack."

Notes

[1] For example, In 2007, the College won the Green Gown Award for Sustainable Construction. And in 2008, it won a Green Business award and the Carbon Trust standard for reducing carbon emissions. See news story on the College website.

[2] Out of the 47 energy saving opportunities registered in the Demand Logic system, 21 have so far been analysed in detail. For each one, a high and low estimate of the saving was calculated by estimating a minimum and maximum electricity and gas reduction (for example through analysing run-times and plate-ratings). This analysis is available on request. Analysis of the remain 26 is in progress. An average 'annual saving per opportunity' was derived (£8278). This saving was assumed to apply to the rest of the sample. The total finding ranged from £181,000 per year (worst case) to £598,000 per year (best case). The middle figure of £390,000 was used above.

[3] Savings opportunities came from both gas and electricity reduction. Using the prices paid by the college, the carbon-per-pound for gas was 6.33 kgCe/£ and for electricity was 6.75 kgCe/£. An overall intensity of 6.5 kgCe/£ was assumed in order to convert from pounds saved to approximate carbon emissions avoided.

Demand Logic was installed on three campuses at King's College: Strand, Denmark Hill and Guys


Needle in a haystack: A personal electric heater in one of these rooms caused the huge central chillers to come on in the middle of winter. This was discovered because the Demand Logic system monitors each air-conditioning unit, and found the one demanding unusual amounts of cooled water.


A college campus represents a real challenge for energy efficiency due to the great diversity in building types and usage patterns


"To be honest, I think this is just the beginning at King's. The system found the low-hanging fruit quite early on, and then we focussed on developing even better methods for analysing data. Now these are going live, I am convinced we'll find many more savings."

Mike Darby, Chief Technical Officer, Demand Logic

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