When you think you’ve done everything – what’s next?

Industry comment

Published: 13 December

Author: Geoff Newman

Type: Industry comment

Year: 2013

As FMs become increasingly involved in the energy performance of their buildings, a key challenge is how to deliver continuous improvement in energy efficiency. Once the obvious areas have been tackled, such as automatic meter reading, voltage optimisation, behavioural campaigns, lighting upgrades, optimising the BMS etc., what comes next?

One thing to consider is whether individual plant is being properly controlled. They may have one or more levels of control, but is each piece of plant fully optimised to deliver maximum efficiency? Or can more be done?

This principle can be illustrated by considering a typical boiler system, where the boilers may be controlled by a building management system (BMS), weather compensation, demand control and boiler sequencing. Even when all of these have been optimised there is often scope to achieve further savings of between 10% and 25% by optimising each individual boiler to address the problem of boiler dry cycling.

The exact savings that can be achieved vary from one project to another but, as an example, installation of 111 M2G intelligent boiler load optimisers to HMS Sultan was shown to deliver a 12% energy saving (based on CUSUM analysis), with a return on investment within 1.4 years. Similarly, Lincolnshire County Council reduced its gas consumption by 15% across 23 properties by retrofitting M2G and is now installing M2G to over 1,200 boilers within its school estate.

These savings are over and above the control strategies that were already in place, because BMS and other boiler controls aren’t typically configured to detect or prevent boiler dry cycling. So this is an obvious area where investment in additional levels of control can return significant savings.

Choosing the right technology

Boiler dry cycling is not a new phenomenon, engineers have been aware of it for many years – and is found in boiler houses regardless of the age and size of the boilers. As a result, early attempts to control it tended to delay boiler firing based on historic firing patterns and not real time data or artificially lower each boilers set point temperatures and as a consequence compromising comfort levels and potentially conflicting with the existing controls i.e. BMS. It is therefore essential that any additional controls can be integrated with what is already there and add to the savings that are already being made.

M2G integrates and complements any BMS system, including controls such as weather compensation, boiler sequencing and optimum start control. As Glenn Chatwood at HMS Sultan observed: “The M2G’s ability to work in harmony with our existing BMS and any future BMS upgrades and deployments was a prerequisite for us and this has been proven since the installation of M2G.”

Consequently, it’s important to ensure you understand the principles of the technology under consideration. The technology providers you are considering should be able to explain how their product works without trying to lose you in technical jargon - and guarantee their product won’t interfere with existing control strategies. Remember boilers respond to temperature not time – so any product which uses a time delay or artificially lowers the boilers’ designed set-points could cause you and your building problems.

Secondly, it’s worth talking to other users of the technology to gauge their views on how well the technology has worked and also how efficiently the project was delivered. A supplier that has experience of delivering complex projects with minimum input from your department will help to take the pressure off your in-house resources.

Additional peace of mind comes from working with a supplier that has staff certified to the International Performance Measurement and Verification Protocol (IPMVP). David Bakst, Sabien’s Operations Director and Certified Measurement and Verification Professional (CMVP), explains: “The IPMVP defines a best practice framework for quantifying the results and benefits of energy efficiency investments. Importantly, it ensures that there is total clarity and transparency for all parties in relation to the scope of work from initial planning, the measurement methodology, through to the validation of results.”

Above all, whatever energy saving project is being considered, it always pays to adopt a questioning approach and understand exactly what is planned, what it should achieve (and how this will be validated) and how the project will be implemented in the best way for your organisation.

Useful links

What is dry cycling?

What is M2G?