Three Key Elements That Lead to Savings

by JONATHON CANDY Energy Manager at Mitie Sustainability

In my opinion, the three pillars of Energy Management are data, Mechanical & Electrical (M&E) and BMS. Individually they don’t add up to much, but bring these three pillars together and they become mutually compatible allies.

Typically there are two types of data which you would gather from an audit. These are as follows:

• Building data: This equates to things like building pattern of use, architectural design, HVAC design and specification.

• Operational data: This includes energy data, half hourly gas and electric. I may also have the availability of sub meter data although during the initial phase of an audit this may prove to be too burdensome to deal with. Other types of data include BMS data which will give an indication of how well the plant is performing. It is possible that the BMS isn’t set up to correctly gather data. If this is the case, then this needs to be addressed quickly.

The next step

Once I have a reasonable understanding of this data, I can bring together the M&E team and the BMS controls engineer to progress the scope for operational change. Typically, M&E and BMS don’t communicate well together. The M&E team may not have energy as part of their KPI and the scope of the controls engineer may be limited to maintaining the system to the existing design which will involve making sure the system is properly backed up and that the sensors and actuators work correctly. In terms of saving energy, this is completely inadequate and as the incumbent energy manager you will need to take full control of BMS controls engineer’s scope of work. Adding additional controls engineering days does come with a cost, but this cost will generally be negated by the savings.

From the initial survey, we should by now have an understanding of what the savings potential might be and therefore the number of additional days we can add in order to make these savings achievable. Typically the savings far outweigh the costs. During the initial BMS visit we would carry out a more detailed review of the system as we now have a greater ability to interrogate the system. As a basic list of items to check I would start off with the following:

• Time schedules. Are they right for the building?

• Plant control strategy. Is it the right strategy for the plant or right for the building?

• Data quality. Is enough data being logged to allow you to successfully determine if the plant is performing correctly? If no data is being logged it would be fair to say that we cannot determine if the plant is performing correctly or not, neither can anyone else.

• Set points. Are these appropriate for the situation? A good example is heating and cooling ambient hold offs; if these are a mile off where they should be, then this is a clear indication that there are some good savings to be made. This could also indicate that there could be some serious plant or building issues.

• System oscillation.

• M&E repairs. This allows us to provide feedback to the M&E team regarding any mechanical repairs they have not identified during their planned maintenance regime.

During this initial visit, it might be possible to make some small changes that will help to get the ball rolling.

The road block

At this stage, it is also important to engage with the M&E team – it is often the case during the initial visit that you will get some push back from the M&E team. Their involvement with the BMS system may be limited or they may have a good knowledge, either way getting the two sides together will often pave the way for more change.

They will want to know what you intend to do and the reaction to this will typically be one of the following:

• ‘We have done that.’

• ‘We have already had a billion consultants giving us advice to no affect.’

• ‘Cannot do that, we get bombarded with complaints.’

• ‘There are lots of problems with the building /plant that will prevent you from carrying out the changes you want to make.’

The simple answer for all of the above is that you are here to help, and from then you can open up the discussion around some of the evidence you found in the audit. For example, the scheduling may start at 2 am but the CO2 data suggest that building occupancy starts at 8 am. This will allow you to get some movement on the timings and over a number of visits push these back to more suitable start times.

The other important thing to remember is not to make too many changes at once, otherwise if there is a problem you end up reverting back to the original settings and starting again from scratch. Normally on a typical optimisation visit, I would have made all the changes very early on in the day and the rest of the time is spent adding functionality that will give us better information on which we can build a scope for further change.

Risk

I have recently been fortunate to gain experience optimising data centres. Again working with the M&E team but this time the road block was risk. My learning path was from carrying out the surveys and from this I found that we had a number of different scenarios for which we had solutions but no appetite for change due to the risk involved. We did some minor works on the BMS to improve information availability from which we were able to open up the scope of the conversations. After some time, I was given back my list of improvements, but they are no longer mine, the M&E team own the solutions. The task for me has therefore been more about change through education, for example we may see in the data that a compressor is short cycling on low load. Instead of saying that it is controlling badly I can ask ‘why is this behaving in this way? Is there a way we could influence the control so that it is on more often or off completely?’ We then move on and look at something else. The process then is that sometime in the future the M&E team have a light bulb moment and come up with a solution that is then implemented in the PPM. I then get an email to approve the change.

From the two examples above, we can see that the M&E team can at first appear to be difficult to deal with and in the worst case can block change. You can also see that if you persevere through the early stages they become more helpful in bringing ideas to the table and do some of your work for you.

BMS contractors come in different packages, both in terms of plant knowledge and skill in manipulating control strategy. I am very lucky in that as part of the business that I work for we have a large experienced BMS team, and it is very much the case that if I identify a change that needs to be changed then I can simply send them a scoping document and they will get on with it. On occasions, I have sometimes had to work with third party controls contractors and it is usually the case that I have to look after them a little bit more and make sure any changes are fully tested, even something simple can prove troublesome as I have found to my cost.

Monitoring the results

After you have engaged with the two pillars, M&E and controls, it is time again to check the third pillar, data. For me this is the most exciting part of the job. I check all the sites I manage as often as possible, every day. I will be looking at the performance of sites where I have made changes to see if there is a benefit. It could also be the case that the M&E team have made some changes that have an impact on energy which I will need to check. The other reason to make regular checks on data is to identify any changes which could be possible due to operational change, people movement, plant failure and plant in override.

If you are being measured on savings, then a single piece of additional equipment could wipe out a significant chunk of the building savings. Therefore following on from an increase in consumption, it is important that this is followed up by an investigation which could be a phone call to the FM or a visit to the site. I experienced a good example of this a number of years ago where my base load consumption went up by over 60 KW. The base load was actually a good clue as we had previously got this to quite a low level therefore we identified that there was an issue with the IT cooling equipment. In this case, the building had suffered a lighting strike which had scrambled the control in two of the computer room air conditioning (CRAC) units. We had one in heating, one in humidification and one trying to compensate for the failure of the other two. We were quickly able to resolve the problem and get the base load back under control.

If changes to the controls have taken place it may be necessary to revisit the site to review the data to check that the control outputs are responding to the inputs in the correct manner.

To sum up. There is a clear simple process to follow:

1. Gather data, building and operational.

2. Review the data and build a scope for change.

3. Engage with M&E and BMS. Get them talking to each other, carry out change and redefine scope.

4. Monitor the data for change and go back to step 3.

Without proper management, it is unlikely you will get best value out of either the M&E or the BMS contractor, but if an energy manager takes control of these two important strategic partners, then it is likely that you will get an improvement on quality and ultimately reduced energy bills leading to a net cost saving.

Author’s profile: Jonathon has a background in Electrical and Electronic Engineering and currently works as an Energy Manager for MITIE energy. He has 15 years’ experience of trouble shooting SCADA systems (supervisory controls & data acquisition system) for major clients in the UK and around the world, prior to a career in building services consultancy and finally Energy Solutions management.