The DIY Building Energy Audit – Plastics Manufacturing

Conducting your own building energy audit, or site survey, to assess your energy use is a smart way to get an overview of your facility’s energy consumption. Only by an in-depth understanding of how, when, where and why you use energy can you improve your plastics manufacturing plant’s energy optimization and practices. The goal? Walk around your site as if you were an energy manager, on the hunt for some rapid no-cost or low- cost improvements that can be made to save money. Don’t be intimidated by how qualified you are for the job—you’ll be surprised by how much you may identify as wasteful when you are observing your facility through the lens of energy efficiency.

The first step of a building energy audit is the walk-around. In fact, it’s a good idea to do several walk-arounds of your site at various times for a complete picture of the plant’s processes and behavioral habits of your staff. Using the checklist that follows, observe what happens mid-shift, at lunchtime, at night, and over the weekend. Checking energy use at various times gives you a better sense of the overall energy pattern and a clearer take on when energy gets wasted most.

Building Energy Audit Checklist

These questions, adapted from Reduced Energy Consumption In Plastics Engineering European Best Practice Guide and Tangram Technology’s Energy Efficiency in Plastics Processing, will guide you in conducting your survey:

  • Which areas have the largest electrical load? Typically the largest machines have the largest motors and create the largest load.
  • Do all the machines have sufficient heat insulation and is it in good condition?
  • Are there lines that are shut down but still have ancillary equipment running?
  • Are there any good reasons for machines to be kept idling to be ready for the next production run?
  • Why are the motors the size they are?
  • Would a smaller motor be more efficient?
  • Are cooling water pumps and chillers set at the most efficient temperature?
  • Is your plant in an area with cold winters?
  • Could you use ambient exterior air during winter months to help cool process chill water?
  • Could variable speed drives be used instead of fixed speed, especially where the airflow from fans is being throttled back with dampers?
  • Where can you hear steam and compressed air leaks?
  • Anytime you hear a hissing noise it is costing you a lot of wasted energy. Is the compressed air system still running even when there is no production?
  • Is it sited in the most suitable place and set to the appropriate pressure?
  • Is compressed air being used for expensive applications where other cheaper methods, such as cleaning and drying, can be used?
  • Are vacuum pumps sited in the most suitable place, such as near the major user, to avoid losses?
  • Is the lighting dirty? Broken? Dim? Difficult to access?
  • What are the best maintenance measures that can be adopted to reduce energy use?
  • Are ‘accepted’ practices wasting energy? Can they be easily modified?
  • Are there clear instructions for all machines and products to ensure best practices are implemented?
  • Do staff members routinely exhibit energy-wasting behaviors (i.e., leaving lights on when leaving spaces, propping doors open, etc.?)

Turn the Building Energy Audit into Energy Savings 
Of course, the most important step in this process isn’t conducting this survey—it’s taking action as a result of your findings. Use the survey to estimate the excess energy usage of the site, identify operating practices that cost money, and indicate improvements that can be made. Involve key members of the staff, both to identify problems and opportunities and to ensure they feel part of the process. Holding a brainstorming session to determine how to prioritize the most critical energy-saving projects can be a dynamic way of ensuring staff buy-in.

A natural outcome of the site survey is the creation of an energy policy that becomes embraced as part of the company’s broader environmental policy. Often, a designated energy manager whose main purview is energy accountability follows policy development. With improved energy efficiency infrastructure and staff, energy savings can be quantified—and promoted. A company can then leverage those savings to create a favorable climate for investing in other energy systems optimization upgrades. That’s the ultimate goal of the site survey: to set in motion an energy awareness cycle that can be a catalyst for systemic change.

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