When you have decided to select an energy analyst to compliment your project team, understanding what energy analysis is will help ensure that you select a qualified professional.
Energy analysis in its broadest definition helps evaluate the energy performance of buildings and equipment through both direct metering and measurement (also called monitoring and verification) and computer simulation. Energy analysis encompasses daylighting analysis and commissioning.
Within the Leadership in Energy and Environmental Design (LEED) framework, energy analysis typically incorporates modeling for optimizing and predicting:
Energy performance, including HVAC, lighting, water, daylighting, and building-envelope analysis.
- Thermal performance.
- Ventilation effectiveness.
- Occupant comfort.
- Life-cycle-cost analysis.
In addition, it encompasses metering and energy analysis for ongoing monitoring and verification of building systems and calculations related to water efficiency and indoor environmental quality.
Other related areas of energy analysis and modeling include modeling of urban heat islands and urban-air-shed modeling.
The majority of energy analysis in the LEED program centers around completing a "building energy simulation model." This refers to a commercially available software program that performs hour-by-hour simulation of a building. It incorporates all building-envelope, building-system, schedule, utility-rate, cost, and weather data.
A building simulation model is required work to earn up to 20 LEED points. A computer model helps architects and engineers find the best combination of material and systems for a given set of project-specific goals, but it does not necessarily guarantee an energy-efficient building. It is a prospecting tool that, in the hands of a dedicated and experienced user, can indicate which combination of building strategies is most likely to produce a building that is energy-efficient, has the desired thermal performance, and is a comfortable and healthy environment in which to live and/or work. A properly constructed model will allow the design team to vary several different aspects of the construction and evaluate the impact these changes would have on the economic and environmental bottom line.
Firms specializing in mechanical engineering, electrical (lighting and daylighting) engineering, commissioning, or energy management are good places to start when looking for a qualified energy analyst. A firm dedicated to energy analysis may have depth of knowledge and experience in evaluating a wide range of project energy issues.
Questions to Ask
When selecting an energy analyst, review the general guidelines for selecting a green design professional (see "Steps to Selecting a Sustainability Professional," HPAC Engineering, October 2011, http://bit.ly/sustainpro). Then review the 10 questions specific to energy analysis below. This guide will help you conduct a thorough selection process.
1. What hourly energy-analysis programs is the firm experienced in using?
Typical hourly energy simulation programs currently in vogue are DOE-2 (via simplified user interfaces such as eQUEST), Trane's Trace 700, and Carrier's E-20 HAP. There are myriad other commercially available programs. Consult http://1.usa.gov/uj3NxD for a list of the more common programs available and in use today. At a minimum, the firm should be experienced in applying the Energy Cost Budget Method, LEED Energy Modeling Protocol, and International Performance Measurement and Verification Protocol (IPMVP).
2. What energy analysis spreadsheets does the company use?
For some needs, detailed building hourly simulation is overkill or not required to obtain LEED credit. Firms often develop their own proprietary spreadsheets. Ask to see a sample or two and be sure to verify that these spreadsheets conform to requirements of the IPMVP.
3. What is the firm's experience in life-cycle-cost analysis?
The firm should demonstrate experience with life-cycle-cost analysis for the types of design alternatives that are part of your project.
4. How does the firm ensure the use of accurate life-cycle-cost information?
A combination of in-house energy expertise, discussion with other project-team members, cost-estimating manuals, and information from installation and service contractors and equipment manufacturers should be used to complete the life-cycle-cost analysis.
5. If metering equipment is to be used, what equipment does the firm use for direct measurements/metering and what is the firm’s experience in monitoring building energy performance?
Get a list of the equipment owned by the company and equipment that typically is rented. Your company may have preferences as to the type of equipment used. Monitoring building energy performance can involve a combination of engineering calculations using metered data, utility-bill tracking software, regression analysis, and building calibration using hourly computer simulation programs.
6. What building energy systems is the firm experienced in modeling, which of these system options would the firm recommend for your project, and how will the firm use its experience to recommend these appropriate system alternatives to the design team?
This will give you a sense of the firm’s past modeling experience and how it will use this experience to provide educated recommendations on your project. It also will give you a sense of how the firm will structure communications with the design team to get buy-in to design concepts that may be unfamiliar to the design team and how they will contribute to influencing the design direction of the project.
7. What type of experience does the company have with utility-bill tracking/analysis and establishing building baselines (building calibration)?
Knowledge of utility-rate structures is key in energy-analysis work. There are as many rate structures as hours in a day, and knowledge of these shows experience. Knowledge of effective energy-conservation measures and the performance-contracting process is important. It may be a benefit for the firm to have knowledge/experience with the following commercially available tools to analyze, track and monitor utility bills and costs if these are a part of the project: Faser, Energy WatchDog, MarketManager, Metrix, and Energy Star Benchmarking Tool.
8. Who will be performing the energy analysis?
Ask to get the personal resume for all people who will be involved in the energy analysis, as well as a description of each person's core skills and value added to the energy-analysis effort. Meet these people if you will have direct communications with them during the project-implementation process.
9. What is the firm’s project-management approach (to ensure quality of energy analysis)?
Be sure you are comfortable with the process used by the firm to ensure quality services and manage risk.
10. Why should you hire this firm to do your project?
Have the firm give you its reasons for why you should hire it. This will let you know if the firm understands the needs of your project and how its experience meets those needs. Answering this question may bring to light additional direct and indirect benefits the firm will bring to the project and help make the final decision.
Peter C. D’Antonio, PE, CEM, LEED AP, is president of PCD Engineering Services Inc., an award-winning provider of building-energy-analysis, mechanical/electrical-design, and commissioning services. His work has been recognized with design and service awards from organizations such as the U.S. Environmental Protection Agency, the U.S. Green Building Council, the Colorado Governor’s Energy Office, and the Colorado Renewable Energy Society. He is a member of American Society of Heating, Refrigerating and Air-Conditioning Engineers Technical Committee 7.6, Building Energy Performance.
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