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:
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!
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.
Right now, many building managers do not have access to the information needed to make the most energy efficient capital improvement decisions. Information such as energy saving measures, paybacks and life cycle costs of implementing energy efficient strategies are integral. This barrier has deterred the momentum of energy efficient building systems. The solution to help building managers make energy efficient capital improvement decisions are energy audits. Energy audits can identify where energy is being expended (and/or wasted) and provide methods for improving a building’s performance.
What is an energy audit?
An energy audit is a systematic approach to quantify how building systems are currently performing, how performance can be improved, what benefits will occur if these improvement are implemented and the cost and payback for each improvement. The goal of the audit is to identify ways to reduce energy consumption in the building by giving information to owners so they can make informed business decisions. I recommend applying an ASHRAE Level II energy audit, as it is simple yet comprehensive. Below are all the steps taken to achieve a Level II energy audit:
- Preliminary Energy-Use Analysis: Includes a general space analysis, utility bill analysis, Energy Utilization Index generation and comparison to similar buildings.
- Level 1: Walk-through: Includes the investigation of operational practices via interview, space function analysis, rough estimates of energy end-use, identifies low or no cost changes to the facility or O&M procedures, potential capital improvements for further study and provides an initial estimate of potential costs and savings.
- Level 2: Energy Survey & Analysis: Includes a review of mechanical, electrical and plumbing design and operation, maintenance problems, comparison of key operating parameters to design levels, annual energy end-use breakdown, equipment modifications and practical measures and financial and cost analysis.
Who can perform an energy audit?
Energy audits can be facilitated by owners/facility managers ,however, public utility and independent, private sector companies will provide important third party perspective.
There are many individuals that can perform energy audits, but who is truly qualified? According to NYC, the following five types of certifications are approved to provide PlaNYC Local Law 87: Energy Audit and Retro-commissioning (to be discussed as a future topic):
- NYSERDA approved FlexTech consultants
- Certified Energy Manager (CEM)
- Certified Energy Auditor (CEA)
- High Performance Building Design Professional (HPBD)
- Multi-family Building Analyst (MFBA)
Have you had an energy audit done on your building? Share your experiences in the comments below. My next blog will explain the term benchmarking, which can help you to understand how your building operates in comparison to similar buildings and explain why this is important.