'Go-to' strategies for energy management

Condition-based maintenance will allow you to assess your building envelope and plug your leaks

05/20/2013


“Energy management” is a term that has a number of meanings, but I’m sure most folks are mainly concerned with the one that relates to saving energy in businesses, industrial environments, and public-sector or government organizations. When it comes to energy savings, energy management is the process of monitoring, controlling, and conserving energy in a building or organization.

Typically, this involves the following steps:

  • Metering your energy consumption and collecting related energy data.
  • Finding opportunities to save energy and estimating how much energy each opportunity could save. You would typically analyze your meter data to find and quantify routine energy waste, and you might also investigate the energy savings that you could make by replacing equipment (e.g., low efficiency motors replaced with high efficiency, lighting, upgrade or replace piping insulation).
  • Taking action to target the opportunities to save energy (i.e., tackling the routine waste and replacing, upgrading, or repairing the inefficient equipment). Typically, you would start with the best opportunities, as defined by ROI.
  • Tracking your progress by analyzing your quantifiable meter data to see how well your energy-saving efforts have worked. 

When you look around, there are a large number of companies that provide energy management services offering a vast array of products and services that are intended to help the end user not only understand its inefficiencies but the actions it can take to become more energy efficient and responsible. I have personally had the experience of working with multiple clients in differing industry verticals and have seen how equipment reliability and energy efficiency go hand-in-hand. The ability to understand how and why equipment fails is essential in understanding and developing energy-efficient strategies for the operation and maintenance of industrial equipment.

This will come as no surprise. Energy costs are rising and becoming a larger percentage of costs for industrial plants and facilities alike. Plant and facilities managers are looking for savings but are wary of full-scale, costly energy savings programs. However, most I have spoken with are interested in “low or no cost” opportunities if prioritized and executed in a way that funds future activities. I often refer to this as a “paying it forward” approach. 

Analyzing savings and opportunities

Figure 1: Follow-up system level audits. Courtesy: Allied ReliabilityBecause all plants and facilities are unique in their own way, opportunities are plant or facility dependent. This dependency makes the “paying it forward” approach extremely flexible. The flexibility begins with an initial current state analysis, which would identify future threats to profitability and ways to reduce costs. The identified opportunities should, therefore, become an integral part of the corporate strategy to counter such threats and improve profit margins through energy savings. Applying good energy management practices is just as important to achieving these savings as the appropriate process technology. It should be remembered that any operational savings translate directly to bottom-line improvement, dollar for dollar.

During a current state analysis, the plant or facility systems will be identified and evaluated for follow-up “paying it forward” energy opportunities. While most facilities and plants have common systems, such as HVAC, electrical distribution, and lighting, others are building specific, such as compressed air or steam.

Generally speaking, the types of follow-up system level audits are illustrated in Figure 1.

While each of the items listed above is important and savings are significant, each has a different ROI valuation. Some represent large savings and relatively quick ROIs, while others are steady savings over a longer duration. In the remainder of this article, I’d like to draw your attention to the auditing of the building envelope, which can help (plants and facilities equally) identify where conditioned air is leaking or outside air and other matters are entering, causing systems to work harder (HVAC, steam, etc.) and be less efficient. 

What is the building envelope?

Figure 2: Building envelope functions. Courtesy: Allied ReliabilityTo begin our discussion about building envelope, let me start by defining it as all of the components that make up the shell or skin of a building. These components are designed and utilized to separate the exterior of a building from the interior. The building envelope may also be defined as the components that separate conditioned areas from unconditioned space.

Building envelopes are designed by project architects and engineers to meet the needs of each individual application (i.e., distribution warehouse, food processing facility, automotive manufacturer, commercial facility, etc.). The building envelope must be carefully designed with regard to climate, ventilation, and energy consumption within the structure.

By serving the four basic functions of a building envelope, as shown in Figure 2, the envelope affects ventilation and energy use within the building. This is a key point to understand when identifying and quantifying related energy cost savings opportunities.

Figure 3: Advantages and disadvantages of tight and loose building envelopes. Courtesy: Allied Reliability

Building envelopes are often characterized as “tight” or “loose.” A tight envelope is designed and built to allow relatively few air leaks. This often requires significant quantities of insulation, caulk, sealants, and energy-efficient windows to create a tight shell for the building. A loose envelope is designed and built to allow air to flow more freely from the exterior to interior spaces. I should add that a loose envelope may be created by design or may be the result of poor construction.

Debates are ongoing as to the benefits of tight versus loose building envelopes. Some advantages and disadvantages are shown in Figure 3. 


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