I need to monitor energy use in my building, where do I start?


#1

I have been assigned to manage energy use for a new commercial customer. As part of this project I’ll be deploying an energy management system since they have very little information on how they use energy. I’m willing to apply best practice to optimize budget and results, any suggestions?


#2

Because sites’ layout and electrical installations are unique, it is difficult to know what needs to be monitored to get a full picture of energy use within a building. Any monitoring and targeting project must therefore start with a site survey to learn the status quo.

Site surveys must be carried out to define the exact monitoring requirements to support your project’s execution and validation. In particular, site surveys are necessary to:

  • Gather information about electrical installation
  • Devise clear energy management/breakdown strategy
  • Quote exactly what is going to be installed
  • Avoid surprises
  • Serve as reference to go back to when managing conflicts with end-customer

Step 1: Get a quick understanding of what you really want
Your project specifications are mostly driven by what you are trying to achieve. Ask yourself a number of questions:

  • Have you got any metering system in place already
  • Do you want specific equipment to be monitored
  • Do you already know how energy is used throughout the site
  • Do you know the main energy offending machines and areas
  • Are you interested in electricity, water and gas metering, or more
  • Have you already conducted an energy audit to base your work on

This information helps focus the site survey and match your expectations.

Step 2: Get an overview of the electrical installation setup
Electrical installations are generally the result of original installations combined with a number of changes and upgrades made over the years to accommodate site expansion or new business requirements. Subsequently, electrical wiring is very often not optimised or logical, and more importantly poorly documented. A number of checks should be made to provide you with the most up-to-date information.

  • Get your hands on the electrical wiring diagram and ask your site electrician to explain it to you and to point what recent changes have been made

  • Take a tour to the main switch room where all the site distribution boards are fed from to get a better understanding of what you are working with

  • Walk-through the building to locate the main distribution boards and their type as a way to assess the monitoring complexity

  • Pictures, pictures, pictures… notes, notes notes… sub-board cabinets, labels, wiring sheets, cable size, MCB size, etc, anything that will help establish the current setup

Labeling is the key to a successful installation, and non-existent or incomplete labeling of circuits can jeopardise profits. No labeling means that the link between electrical loads and circuits monitored is unknown. When labels do not exist or exist but are incorrect or meaningless then the measurements collected are misleading. Inconsistent labeling should be identified at this stage, because you may otherwise need to lengthen, postpone or cancel the works at a later stage.

Step 3: Find out how you can deploy your system
Deploying a monitoring system comes with a number of requirements in terms of power supply, access to cables and access to the Internet.

  • Where can the meter be located (DIN rail/panel mount), will you need a separate enclosure
  • Where will the CT leads pass through to reach the cable chamber from the meter(s)
  • Is there a spare MCB and neutral that can be reused for the installation or must they be deployed. Can they be deployed on installation date considering board shutdown is necessary for that
  • Are wall sockets available to power up laptop for installation or GPRS/3G router
  • Can your network infrastructure be used to connect the metering system to the Internet
  • Is there a wired Internet point in the vicinity of the board that can be used
  • Is the GSM signal strong enough should a GPRS/3G router be needed (you can check with your phone)

Step 4: Discover future problems early

Some issues are more annoying than others, as they can dramatically delay an installation and occur massive hardware and labour costs that would not be budgeted in the first place. Some examples of recurrent issues are:

  • Components of a same machine are fed from multiple distribution boards in different locations, e.g. production line, meaning that metering equipment must be deployed at multiple locations.
  • A circuit feeds more than one machine, meaning that metering equipment must be moved to the level down closer to the machine of interest
  • Circuits can only be powered down during scheduled shutdown periods, meaning that circuit breakers and current sensors must be deployed prior to installation or at a agreed dates such as week-end
  • Labels are non-existent or not clear, meaning you must go through a tedious labeling exercise
  • Existing equipment does not work as expected, e.g. existing pulse meters are defective and do not issue pulses, meaning that you must take into consideration troubleshoot of 3rd party systems

Step 5: Size effort for dealing with 3rd parties

Now that the electrical wiring is pretty clear and you have a picture of how you’re gonna tackle the metering aspect of your installation, you must not forget the work related to dealing with all the various organisations over the course of the project. Very often project management proves to be time-consuming as you must go to site and meet various people to get the information you need. The items below should be considered:

  • Switching off loads: is management pre-approval required, should a person with authority be present during installation, can machines or circuits be switched off, etc
  • Integrating 3rd party systems: who can get you authorization to request data from the energy provider or connect loggers to Utility meters. Communication with city councils and energy providers can be tedious and lengthy, datasheet and technical information may not be available.
  • Obtaining tariff information: what are the tariff and charges applied, is the tariff structure standard
  • Access to IT network: what are the requirements, is the IT team aware and available to help.
  • Access to on-site electrician: can site electrician label circuits and install circuit breakers before installation date. Is on site induction required?