Session 5

Introduction to the elements of commercial energy auditing

Week 5

• Understand the need to manage energy and how systems use and waste energy

• Address areas of concern to the facilities• Understand aspects of building energy use typically examined in an audit• List the types of data required to provide an exhaustive audit• Understand different types of energy analyses that are part of an audit• Understand the fundamentals of utility data analysis• List several typical energy saving strategies• Understand the basics of an audit schedule and final report• Research ENERGY STAR for commercial and industrial buildings and

facilities

How much energy can the we use? 350 years of energy use: a worldwide public health issue.

Problem Statement: Buildings use 60% of all electricity in the U.S. There are 4.5 million commercial buildings with 55 billion square feet of space. It is estimated that non-residential buildings convert 35 percent of all energy. Also according to the DOE & the EPA, it is estimated that US buildings use about 25% more energy than necessary, mostly because of outdated inefficient infrastructures. And it is not just older buildings that are poor performers, new buildings are among the worst.

Understand the need to manage energy and how systems use and waste energy

ASHRAE Level 1 – Walk-Through Analysis/Preliminary Audit

The Level 1 audit alternatively is called a “simple audit”, “screening audit” or “walk-through audit” and is the basic starting point for building energy optimization. It involves brief interviews with site operating personnel, a review of the facility’s utility bills and other operating data, and an abbreviated walk-through of the building. The ASHRAE Level-1 audit is geared toward the identification of the potential for energy improvements, understanding the general building configuration, and defining the type and nature of energy systems. The audit should result in a preliminary, high-level, energy-use analysis for the entire facility, and a short report detailing the findings, which may include identifying a variety of recognizable efficiency opportunities. Usually this report does not provide detailed recommendations, except for very visible projects or operational faults.• The ASHRAE Level-1 audit is intended to help the energy team understand

where the building performs relative to its peers; establish a baseline for measuring improvements; deciding whether further evaluation is warranted; and if so, where and how to focus that effort. The Level-1 also will outline the range of potential financial incentives available from Federal, State, Local, and Utility sources.

ASHRAE Level 2 – Energy Survey and AnalysisThe next step for most facilities is the ASHRAE Level-2 audit/assessment. The Level-2 project starts with the findings of the Level-1 audit, and evaluates the building energy systems in detail to define a variety of potential energy-efficiency improvements. This should include the Building Envelope, Lighting, Heating, Ventilation, and Air Conditioning (HVAC), Domestic Hot Water (DHW), Plug Loads, and Compressed Air and Process Uses (for manufacturing, service, or processing facilities). This study starts with a detailed analysis of energy consumption to quantify base loads, seasonal variation, and effective energy costs. From there, the study should include an evaluation of lighting, air quality, temperature, ventilation, humidity, and other conditions that may affect energy performance and occupant comfort. The process also includes detailed discussions with the building Ownership, Management, and Occupants to explore potential problem areas, and clarify financial and non-financial goals of the program.• The Level-2 audit should result in a clear and concise report and briefing with the Owner and Management

Team describing a variety of Energy Efficiency Measures (EEMs) including no- and low-cost measures, modifications to system controls and building automation, operational changes, and potential capital upgrades. The findings should include general costs and performance metrics, as well as a means for the Owner to evaluate the EEMs and decide how to proceed with implementation.

• Many of the EEMs revealed during the ASHRAE Level-2 audit can be implemented quickly with rapid or immediate financial payback for the Owner. Other EEMs will require more detailed analysis of benefit and cost and the other goals that are important to the Owner. The audit should define next steps to accomplish this analysis and decision making. Sometimes it is through discussion with manufacturers or suppliers or other relatively simple means. For other EEMs, involving complex interaction among building systems and potentially large financial investments, it may be necessary to dig deeper into the building operation and also the human factors influencing performance. This is where the ASHRAE Level-3 audit becomes essential.

ASHRAE Level 3 – Detailed Analysis of Capital Intensive Modifications

• Some of the system upgrades or retrofits revealed by the Level-2 audit may require significant investments of capital, personnel, and other limited resources. Before making this level of investment, the Owner will want to have a much more thorough and detailed understanding of the benefits, costs, and performance expectations. This is the purpose of the “investment-grade” Level-3 ASHRAE audit. There may be only a few capital-intensive EEMs exposed by the Level-2 audit, or there may be dozens for larger facilities. Investment levels can range from tens of thousands to tens of millions of dollars. In most cases, since this cannot be clearly determined or accurately estimated in advance, the recommendation and scope definition for a Level-3 audit usually is an outcome of the Level-2 process.

• The ASHRAE Level-3 audit focuses on a “whole-building computer simulation”, where a computer program is used to very accurately model the way the brick-and-mortar building would respond to changes in the energy systems, whether those are major HVAC retrofits or architectural modifications to walls, windows, and roof. The ASHRAE Level-3 audit involves much more detailed data collection over the course of weeks or months. Data loggers typically will be placed temporarily to monitor the operation of pumps and motors, temperatures of affected spaces, lighting levels, switching behavior, and other factors. These data are used to calibrate the computer model of the facility, so that the computer model responds to inputs and changes the same way the building could be expected to respond. This calibration is checked and validated by simulating a year or more of past, minute-by-minute climate conditions to see if power and energy usage in the model mirrors actual energy power and energy usage.

• Once the three-dimensional computer model is responding like the real building, changes to energy systems can be simulated with very accurate results. Combining that process with construction-grade cost estimating supports informed investment decisions.

Addressing Facility Concerns

• Interview management • Interview the rank and file • Interview O&M Staff • Share results and build consensus

PRELIMINARY ENERGY USE ANALYSIS -DETAILS

Potential Owner Interface and Information

• Executive Management - Corporate goals

• Facility Managers - Drawing, maintenance policies, previous energy conservation projects, schedule of facilities.

ENERGY AUDIT OBJECTIVES

The objectives of an energy analysis or audit are to identify and develop modifications that will reduce the energy use and/or cost of operating a building. The results should be presented in a format that will provide the information needed by an owner/operator to decide if any or all of the recommended modifications should be implemented.

CURRENT DRIVERS FOR COMMERCIAL ENERGY AUDITS

Demand for energy audit services can be attributed to one or more of the following items:1.Increasing impact of utility costs on overall operation cost of buildings2.Competitive real estate market now including energy ranking as a factor in purchasing a building.3.State and local energy conservation codes requiring higher efficiency for new construction, and building additions or retrofit projects4.Federal, state and local governments and corporate policies demands construction and occupancy in “LEED Certified or Green Buildings”

BUILDING ENERGY CODES AND STANDARDS

TOP 10 COMMON PROBLEMS IN ENERGY AUDITS

Reference ASHRAE Journal February 2011

10. Inadequate review (30% of Audits)9. Overestimated savings (53% of Audits)10. In adequate billing analysis (57% of Audits)11. Poor Building description (60% of Audits)12. Low (or missing) installed costs (60% of

Audits)

10 COMMON PROBLEMS IN ENERGY AUDITSReference ASHRAE Journal February 2011

(in reference section)

5. Poor improvement selection (63% of Audits)

4. No Life-cycle costing (73% of Audits)3. Improvement life too long or not provided

(73% of Audits)2. Weak improvement scope (77% of Audits)1. Missed improvements (80% of Audits)

10 COMMON PROBLEMS IN ENERGY AUDITS

•High efficiency HVAC•High efficiency Domestic Hot Water•High efficiency Lighting•Lighting Power Density•Lighting Control•Wall or Roof Insulation•Motor Drives•HVAC Controls

KEY ELEMENTS OF AUDIT

1. Analysis of current energy consumption.

2. Description and analysis of existing energy using systems.

3. Presentation of engineering and economic analysis.

ANALYSIS OF CURRENT UTILITY CONSUMPTION

Obtain two or more years of utility data, review building plans and conduct site walk-through to establish:1. Type building, principal use, and floor area, ft2 2. Annual Energy Utilization Index, kBtu / ft2 3. Annual Energy Cost Index, $ / ft2 4. Breakdown spaces by function, use and area.5. Determine maintenance problems or practices

affecting energy efficiency6. Conduct Benchmarking to compare energy and cost

indices with similar facilities

DESCRIPTION AND ANALYSIS OF EXISTING ENERGY

SYSTEMSDescription and analysis of the energy-using systems of this building, resulting from on-site observations, measurement, and engineering calculation, including:1. Envelope (wall, roof, floor, slab, windows, doors skylights)2. Lighting (interior and exterior) 3. HVAC 4. Domestic hot water5. Equipment 6. Food preparation7. Conveying systems8. Other systems

PRESENTATION OF ENERGY AND ECONOMIC

ANALYSIS As result of engineering analysis and economic calculations, develop:1. Breakdown of the components of annual energy use and cost2. Recommended energy conservation measures including

predicted savings and cost to implement3. Description and cost estimate of necessary repairs in order for

energy conservation measures to be effective4. A description and cost estimated of measurement and

verification methods needed to determine project effectiveness5. Energy analysis summary

• Present and target energy use and cost• Savings from recommended measures and comparison

to ultimate target

PROCEDURES FOR ENERGY AUDIT AND

ANLYSISProvide sufficient information for the owner/operator to understand:1.Breakdown of the components of annual energy use and cost2.Need to commit necessary resources for building energy costs, operation and maintenance costs including personnel, and any energy efficiency capital improvement projects3.Appropriateness of recommended measures, based on institutional and organization issues (i.e. regulatory environment, financial options, and occupant requirements)4.Understand different levels of energy analysis can be performed based on specific purpose of owner from simple ranking of building energy usage, to contemplating major energy-saving capital improvements requiring significant level of confidence in results of engineering and economic analysis

PRELIMINARY ENERGY USE ANALYSIS -DETAILS

Review of Utility Data• Show examples of data for various

facilities and explain what we can determine from the data about a facility

• Determine potential local utility rebate programs

PRELIMINARY ENERGY USE ANALYSIS -DETAILS

EPA Energy Star Benchmarking • Demonstrate Energy Star

Target Finder analysis (based on U.S. Energy Information Administration - Commercial Buildings Energy Consumption Survey)

• https://www.energystar.gov/istar/

pmpam/

PRELIMINARY ENERGY USE ANALYSIS -DETAILS

2. EPA Energy Star Benchmarking • Demonstrate Energy Star Target

Finder analysis (based on U.S. Energy Information Administration - Commercial Buildings Energy Consumption Survey)

• •http://www.energystar.gov/index.cfm?c=new_bldg_design.bus_target_finder

ENERGY STAR TARGET FINDER

PRELIMINARY ENERGY USE ANALYSIS -DETAILS

EPA Energy Star Benchmarking • U.S. Energy Information

Administration - Commercial Buildings Energy Consumption Survey)

http://www.eia.doe.gov/emeu/cbecs/cbecs2003/detailed_tables_2003/

detailed_tables_2003.html#consumexpen03

PRELIMINARY ENERGY USE ANALYSIS - REPORT

1. Provide description of facility, occupancy, usage and floor area.

2. Present Summary Table / Graph of Utility Bills• Annual totals per fuel, average cost ($/unit)

and cost per sq. ft. floor area

3. Present results of Energy Star Target Finder4. Present preliminary list of potential

operation, maintenance and energy efficiency projects for further analysis.