Tag Archives: retro-commissioning

A Closer Look at Energy Conservation Measures – Window Replacement

As promised, here are more highlights from a recent energy audit and retro-commissioning assessment project. The energy conservation measure (ECM) I’d like to highlight this time is upgrading a facility’s windows.

The majority of the existing windows in our case study are single pane with wood frames in fair to poor condition. With window replacement there is an opportunity for thermal efficiency improvement with the installation of windows with better insulating properties. Typically, energy savings from window replacement are a result of reduced infiltration from gaps and cracks around window frames and glazing and from reduced heat transfer during the heating and cooling season. For a conservative savings estimate associated with this measure, the calculations below are only based on improvements to the windows’ thermal properties.

Overall, we calculated a savings of approximately $5,857/year (based on improvements to the windows’ thermal properties) with a simple payback of nearly 200 years! What can be recommended with these stats? Window replacement was considered, but the economic payback did not justify implementation as an ECM. Therefore, we suggest that when window replacement is required, high performance windows should be used. Replacement windows should have insulated frames (with thermal breaks), two or more layers of glazing with an inert gas “air” gap between and solar heat gain coefficient appropriate for the window orientation and desired level of solar heat gain.

Although not all ECMs end with a recommendation for implementation, this facility can now plan appropriately for the future. When putting together their budgetary needs, they can now reference this study to plan more accurately and most efficiently.

What are some lessons learned from your building energy studies? Have you recently replaced your windows? How did you choose the best fit? Share your thoughts and questions in the comments below.

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Top Tips and Pitfalls of Implementing Energy Conservation Measures (ECMs)

Now that we have developed an energy audit and/or retro-commissioning report, it is time to implement some of our findings. Which energy conservation measure (ECM) to implement has a lot to do with your facility’s priorities and needs. Typically, the ECM that makes the most sense to implement is the one with the greatest return on investment. When investigating implementation, one must keep in mind that some ECMs may be linked. For example, if an ECM involves upgrading your current BMS system, it may initially seem unappealing because of the long return on investment. However, you may want to consider this ECM if it is tied to another ECM, such as adding a reset control or an air side economizer. Both of these are better served if the BMS is upgraded first.

An example of a pitfall, however, includes upgrading current motors to energy efficient motors. I am always a proponent of saving energy, but this particular investment may not make sense based on your facility’s current utility rate and the run time of your motors. A real-life example of this is in a primary school we recently worked. It was identified that the existing HVAC motors were not premium efficiency motors. However, after investigation and pricing, the payback was calculated to be 180 years! This ECM was therefore not recommended, however, if the motors should fail and require replacement, it was recommended to replace them with premium efficiency motors. The most logical thing to do is to work on your low cost/no cost measures. This includes items such as schedules, thermostat recalibrations, sensor recalibrations, etc.

The key to implementing ECMs is to have a plan and document what your intentions are with your report. Identify which measures you are going to implement going forward, who is going to do the work and how you are going to check that the implementation measures were installed correctly and are working. Once we have a plan, it is crucial to share it with ownership so they understand what you are doing with the report and their recommendations

Whether you are planning to use in-house labor or contract labor, a clear scope of work is imperative to making your implementations successful. Clearly define the level of expectations, desired results and most importantly who plans to be in charge of and manage the implementation program.

Scheduling your work to minimize disruptions to your tenants and end users is also important. Having regular job check-in meetings are vital to keeping the project on track with either formal or tool box sessions.

Over the next couple of months, I will be discussing details regarding a dozen or so commonly found ECMs and the pros and cons of implementing them. Stay tuned! As always, if you have any questions, leave a comment below.

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Existing Building Energy Consumption: Current Situations, Trends, Legislature and Solutions (Series Post #7: PlaNYC Local Law 84 and 87)

Energy use in NYC buildings contributes to 74% of citywide GHG emissions through the use of heating fuel, natural gas, electricity and steam. Energy expenses are up to $15 billion per year; therefore, NYC needed to act. NYC responded to this problem with the development of PlaNYC. In particular I’d like to focus on Local Law 84: Benchmarking (LL84) and Local Law 87: Energy Audits & Retro-commissioning (LL87).

“Released in 2007, PlaNYC was an unprecedented effort undertaken by Mayor Bloomberg to prepare the city for one million more residents, strengthen our economy, combat climate change, and enhance the quality of life for all New Yorkers. The Plan brought together over 25 City agencies to work toward the vision of a greener, greater New York. Since then, we have made significant progress towards our long-term goals.”

LL84 began in 2009 and requires owners of large buildings to annually measure and report their energy consumption through the previously mentioned benchmarking practice. In July, they upgraded the online energy star reporting tool (www.energystar.gov/portfoliomanager). They also recently released their second year benchmarking scores (read the report here: http://www.nyc.gov/html/gbee/html/plan/ll84_scores.shtml).

The first energy efficiency reports for LL87 are due at the end of this year. Due dates are based on a building’s tax block id #. Those ending in 3 are required to comply in 2013, those ending in 4 are required to comply in 2014 and so on and so forth. LL87 requires that all buildings 50,000 sf or larger undergo not only an energy audit but also retro-commissioning.
LL87 requires the following base building energy systems to be investigated:
•    Heating, ventilation and air conditioning
•    Electrical and light
•    Domestic hot water
•    Building envelope
•    Conveying systems

The approved certified engineers that can help one comply with LL87 include:
•    Certified Commissioning Professional (CCP)
•    Certified Building Commissioning Professional (CBCP)
•    Commissioning Process Management Professional (CPMP)
•    Accredited Commissioning Process Authority Professional (ACPAP)

Horizon Engineering Associates, LLP (HEA) has conducted nearly 70 energy audits and retro-commissioning projects for LL87 compliance. The facilities have ranged from museums to hospitals. Just to put into perspective how effective energy audits and retro-commissioning has been, when we surveyed 9 buildings, HEA was able to identify over 70 energy conservation measures that, when implemented, will save over $3.36 million in energy costs annually.

Has your building complied with LL84 and LL87? Are you aware of early compliance? Is your city implementing similar laws to NYC’s PlaNYC? Share your experiences in the comments below!

My next post will highlight an energy audit and retro-commissioning case study and comment on my experience with retro-commissioning.

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Existing Building Energy Consumption: Current Situations, Trends, Legislature and Solutions (Series Post #6: Retro-commissioning)

This blog series is focused on different methods to evaluate and reduce energy consumption of buildings. The demand for energy is increasing at an alarming rate and the building sector is one of the largest consumers of energy; gaining more and more prominence over the past few decades. Retro-commissioning is a proven process to help combat this problem. Let’s start with a quick overview of what building commissioning is.

Commissioning is a quality assurance process that provides documented confirmation that a building is operating at optimum level of the owner’s requirements. Commissioning ensures that building systems are planned, installed, tested, operated and maintained the way the owner intended. Commissioning often provides:
•    Increased energy efficiency
•    Maximized occupancy comfort
•    Extended life cycle of equipment
•    Reduces O&M costs

During the retro-commissioning process, existing building systems are inspected for physical, functional and performance conditions. All issues are documented and presented in a comprehensive report to the owner. Diagnostic test equipment is used to assess existing equipment efficiency and operating characteristics. This analysis is used to identify opportunities for energy conservation. The retro-commissioning process usually occurs in four distinct phases as illustrated below:

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A research study on commissioning and retro-commissioning performed by Lawrence Berkeley National Laboratory in 2009 found that the average retro-commissioning project cost $0.30 per square foot with energy savings of 16% and with a simple payback of 1.1 years. Which brings us to the glaring question, why isn’t everyone doing this? Some possible reasons could be unfamiliarity with the retro-commissioning process and fear of any upfront costs. In order to overcome these hurdles, many cities across the nation are recognizing the importance of retro-commissioning/energy audits and are developing legislation that makes it a mandatory procedure. For example, New York City has developed PlaNYC, an agenda to meet energy challenges to building a greener, greater New York. Included in this plan is Local Law 84: Benchmarking and Local Law 87: Energy Audits and Retro-commissioning. In my next blog, I will discuss these laws in detail.

Do you have any questions regarding retro-commissioning? Drop me a line in the comments section below!

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Existing Building Energy Consumption: Current Situations, Trends, Legislature and Solutions (Series Post #5: Intro to Retro-commissioning)

Now that we have an understanding of what ASHRAE is, let’s discuss how their standards are applied, particularly with the retro-commissioning process.

When it comes to maintaining a building, it is important to keep up with the continuous environmental and economic factors attributed to occupancy and utilization patterns. This blog series is intended to highlight the different trends and avenues towards reducing a building’s carbon footprint for an optimized and energy efficient building system. We have identified that buildings present the best opportunity to make a large scale impact towards reducing energy usage. In my earlier posts, we have discussed energy audits and benchmarking as great starting points to access your building’s energy consumption and as a pathway to understanding the functionality of a building. ASHRAE has led the way in providing standards and guidelines to conduct an energy audit, benchmarking and, commissioning and retro-commissioning.

Energy auditing is a practical tool to help determine capital improvement plans. Developing a plan to replace outdated equipment with energy efficient measures is a great way to reduce energy costs. However, this method’s initial costs tend to be higher and return on investments (ROIs) take longer than those of retro-commissioning.

Retro-commissioning enables you to improve the performance of your existing systems by helping you to return your building to optimum performance. It is the number one process that can provide energy efficiency, improved tenant comfort, training for operations staff and improved documentation. Retro-commissioning is a systematic process for optimizing the energy efficiency and operations of existing base building systems. Adjustments that occur throughout this process include, but are not limited to: repairs of defects, cleaning, adjustments of valves, sensors, controls or programmed settings, and/or changes in operational practices. These items are typically low cost to no cost measures that yield high ROIs. Median commissioning costs: $0.30 and $1.16 per square foot for existing buildings and return on investments are typically 13%-15% with payback times of anywhere between 1.0 and 4.2 years. In some cases you are seeing cash on cash returns of 91%.

Good candidates for retro-commissioning include underperforming buildings, older buildings and facilities with large loads. Do you manage and/or own any of these types of buildings? What are common problems you are experiencing? Share your thoughts in the comments section.

In my next blog, I will be walking you through the retro-commissioning process and going into details about each of the four phases.

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Existing Building Energy Consumption: Current Situations, Trends, Legislature and Solutions (Series Post #4: ASHRAE)

American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) is accredited by the American National Standards Institute (ANSI) and follows ANSI’s requirements for due process and standards development. ASHRAE has helped to mainstream the integrity of commissioning by setting guidelines and criteria for the commissioning process. ASHRAE has also partnered with the United Nations Environment Program to drive their global effort in reducing the amount of pollutants released into the atmosphere by buildings. ASHRAE has created an international advisory team to assist developing countries in their goals to institute and revamp relevant codes and standards.

In terms of building commissioning and retro-commissioning, ASHRAE developed Guideline 0 – Commissioning Process and Guideline, which details the process, intent, activities and deliverables that should be followed to optimize benefits. This document has incited the development of numerous supporting guidelines and standards for the commissioning process. In addition, ASHRAE also defined best practices and created different levels of energy audits (Preliminary Analysis, Level 1, 2 and 3).  If you are interested in learning more about these guidelines, visit ASHRAE’s website (https://www.ashrae.org). In particular, they have posted their Fall 2013 online courses here: https://www.ashrae.org/education–certification/2013-fall-online-courses. On October 9th there is a Commissioning for High Performance Buildings course and on November 4th and 6th there is a Commercial Building Energy Audits course.

As part of the PlaNYC initiative to have a more sustainable New York City, all buildings over 50,000 sf are required to file an Energy Efficiency Report (EER) with the New York City Department of Buildings (NYC DoB). This requirement is known as Local Law 87. The EER consists of an ASHRAE Level II energy audit and retro commissioning study of base building systems. Base building systems include systems or subsystems that use energy or impact energy consumption, including: building envelope, HVAC systems, conveying systems, domestic water systems and electrical/lighting systems. EERs are due to the NYC DoB once every 10 years starting this year. The EER reports are due in a staggered schedule, which is based on the last digit of the building’s tax block number.

Do you have any questions regarding ASHRAE and how they are involved with Local Law 87 legislature? Post them in the comments below. In my next blog, I will provide an overview of the second part of Local Law 87 compliance, retro-commissioning.

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