ENPM808W Energy Efficiency/Energy Audit and Conservation Week III, Lecture 1: Energy Audit Procedures and Energy Benchmarking Dr. Michael Ohadi Spring 2015

2ENPM 808W: Advanced Energy Audit Energy Auditing  Energy audit is part of the overall energy program  Audit: official examination and verification of accounts and records  Energy audit tasks per ASHRAE:  Collect and analyze historical energy use  Study the building and its operational characteristics  Identify potential modifications that will reduce the energy use and cost  Perform an engineering analysis of the modifications  Prepare a rank-ordered list of modifications  Prepare a report to document the analysis process and the results

3ENPM 808W: Advanced Energy Audit ASHRAE Commercial Building Energy Audit Levels  Three Levels  ASHRAE Level 1: Walk-Through Analysis  ASHRAE Level 2: Energy Survey and Analysis  ASHRAE Level 3: Detailed Analysis of Capital Intensive Modifications

4ENPM 808W: Advanced Energy Audit ASHRAE Level 1 Analysis  Walk-through analysis  Analyze energy bills  Conduct a brief on-site visit  Brief survey of the building characteristics and occupants  Recommendations on low-cost/no-cost improvements  Preliminary Identification of Capital Improvements

5ENPM 808W: Advanced Energy Audit ASHRAE Level 2 Analysis  Energy survey and engineering analysis  Analyze energy bills in more detail  More detailed building survey  Breakdown of energy use within the building  Review operational and maintenance procedures  Provide savings and cost analysis of all practical improvements  Provide a list of potential capital-intensive improvements

6ENPM 808W: Advanced Energy Audit ASHRAE Level 3 Analysis  Detailed analysis of capital-intensive modifications  Very detailed building survey  Detailed review of operational and maintenance procedures  Detailed building modeling/simulation (Transys, EnergyPlus) with validation from data gathering  Focus on analyzing potential capital-intensive modifications  Provide detailed project cost and savings calculations with a high level of confidence  Obtain actual contractor pricing if possible

7ENPM 808W: Advanced Energy Audit Energy Audit Procedures  Pre site visit  Information gathering  Site visit  Building Survey  Post site visit  Calculate energy savings and generate report

8ENPM 808W: Advanced Energy Audit Pre Site Visit  Obtain review Mechanical, Electrical, Lighting and Plumbing Drawings  Obtain Floor plans  Obtain basic facility physical information  Building area (SQFT), year built, types of utilities  Weather information  Perform a Utility Analysis  Calculate EUI (Energy Utility Index) for Benchmarking

9ENPM 808W: Advanced Energy Audit Site Visit  Survey mechanical, electrical and lighting systems  Envelope  Lighting  HVAC  Domestic Hot Water  Laundry  Food Preparation  Conveying Systems and Other  Identify Energy Conservation Measures  Gather related information such as equipment name plate information, motor efficiencies, lighting measurements etc.

10ENPM 808W: Advanced Energy Audit Post Site Visit  Energy Savings and Payback Calculations  Energy Conservation Measures  List assumptions  Provide basic methodology of the calculations – May be asked to provide more details  Results  Report findings including cost and payback  Provide reasonable cost estimates  Typically expected to be within ±20% for ASHRAE Level 2  Payback calculations  Simple payback = Cost / Savings  Complex (based on time value of money, inflation, depreciation, before and after tax considerations)  Recommendations

11ENPM 808W: Advanced Energy Audit Energy Benchmarking  Utility Analysis  Collect and review minimum 1 year of utility data  Electric, gas, steam, propane, oil, chilled water, etc.  Graph consumption and cost data – Energy load profile, Demand, Load Factor  Look for seasonal patterns and anomalies  Energy Benchmarking:  Important part of ASHRAE Audit Procedure  Calculate Energy Utilization Index (EUI): kBtu/ft²  Cost Index: $/ft²

12ENPM 808W: Advanced Energy Audit Energy Utilization Index (EUI): kBtu/ft²  EUI = Total Energy Consumption of the building divided by the total building area  Site EUI  The Btu value of energy is measured at the point it enters the building  Source EUI (Primary Energy Consumption Index)  The Btu value is equal to site energy plus losses that occur in the generation, transmission, and distribution of energy  Incorporates inefficiencies at the power plants, transmission and distribution lines etc.  Source EUI Varies regionally due to the diversity of fuel sources utilized in the power plants. Average values used under consensus.

13ENPM 808W: Advanced Energy Audit Site Energy Utilization Index (EUI): kBtu/ft²  Total Energy Consumption of the building divided by the total building area  Example: An Office Complex in Landover, MD  345,065 ft²  Annual Electricity Consumption: 5,145,874 kWh – x3.413 kBtu/kWh = 17,562,868 kBtu  Annual Natural Gas Consumption:158,100 Therms – x100 kBtu/ Therm = 15,810,000 kBtu  EUI = 96.7 kBtu / ft²

14ENPM 808W: Advanced Energy Audit Forms of Energy Utilization Index (EUI) Energy/Productivity Indicator AdvantagesDisadvantages Btu/ft 2 -Concise. Most commonly used. -Accurate when process energy is low or constant and weather is consistent. -Very consistent (easy to measure sq feet). -No measure of production. -Doesn’t account for weather -Assumes energy is linear with floor space. Btu/unit of production-Concise. -Accurate when process energy dominates. -Appropriate for comparing plants with similar production profiles. -Difficult to measure “units of production”. -Doesn’t capture high HVAC and/or lighting contributions. Btu/degree day-Concise. -Accurate when HVAC system energy dominates. -Consistent between similar structures/plants (easy to measure or obtain degree day data). -Disregards production energy and process needs. -Buildings with large thermal mass don’t respond as quickly to degree days. Btu/unit-degree day-ft 2 or Btu/unit-degree day -Captures several variables. -Somewhat consistent and more accurate than the above measures. -Can capture a very specific need. -More complicated. -More difficult to comprehend. Btu/sales dollar or Cost of energy/$ sales or $ profit -Easy to compute. -Relates energy consumption to profitability. -Demonstrates $ results, not just conservation. -Does not account for inflation. -Difficult to account for all variables that influence profitability. Btu/direct labor-Similar to a measure of production. -Easy to get accurate data. -Good when process energy is the dominant energy. -Consistent across plants and possibly industries. -Energy is often not linearly proportional to labor costs. -Does not account for high HVAC/lighting demands.

15ENPM 808W: Advanced Energy Audit How to compare EUI between different buildings?  U.S. D.O.E. Energy Information Administration provides statistical data   Databases for Energy Intensity  Residential  Commercial Buildings  Manufacturing Industries  Experience!

16ENPM 808W: Advanced Energy Audit U.S. Commercial Buildings Energy Intensity

17ENPM 808W: Advanced Energy Audit Energy Star Portfolio Manager for energy benchmarking  Free benchmarking tool by EPA and DOE  Interactive energy management tool that allows tracking and assessing energy and water consumption  Manage Energy and Water Consumption for all Buildings  Rate Building Energy Performance  Estimate Carbon Footprint  Set Investment Priorities  Verify and Track Progress of Improvement Projects  Gain EPA Recognition  Improve property value => High profile tenants

18ENPM 808W: Advanced Energy Audit   Create online account  Add new facility  Define space use types  Add energy consumption data  Enter energy bills directly  Obtain energy star score and interpret results  Energy Star 50 = Average Building  Energy Star 75 = Energy Star Certified Building  Requires to be a Licensed Professional Engineer (PE) to certify  Track monthly changes with the score Energy Star Portfolio Manager How does it work?

19ENPM 808W: Advanced Energy Audit

20ENPM 808W: Advanced Energy Audit