Energy Auditing Techniques for Small Commercial Facilities Directions: -Use this slide as the cover power point slide for your given section -Customize this slide by typing in your name and organization Sean Harleman, kW Engineering

HVAC Systems Directions: -Customize this slide by typing in the title of your assigned lecture section from the list below: Introduction to Energy Audits, Pre-Audit Assessment, Lighting Systems, Motor Systems, Commercial Refrigeration Systems, Commercial Kitchen and Food Service Systems, Natural Gas Fired Equipment, HVAC Systems, Envelop Systems, Misc Systems, Demand Response, Financial Calculations, or Renewables. -An additional use of section titles can help to categorize major topic concepts within your slide deck before a group of slides related to specific topic of content is presented. This visually helps the learner transition from one major topic to the next. This also helps to organize the content into chunks of information for a given topic. Sample section titles within Ryan’s power point decks include “The Energy Auditing Process” , “Gas Fired Equipment Efficiencies”, “Demand Response Strategies”

Energy Auditing Techniques Learning Objectives Recognize common system types and controls Understand economizers and outside air Gather useful nameplate data Provide recommendations for replacements Do some simple energy savings calculations Directions: -Customize this slide by typing in the Learning Objectives for your section. -All of the Learning Objectives bullet points must fit within 1 slide only. We recommend using a minimum of 24 point font and a maximum of 32 point font for onscreen text. -When developing the Learning Objectives for your section, we recommend thinking about high level and general key concepts that you would like the learner to know. We recommend building objectives around high level pieces of the knowledge, skills, or abilities from your section. Energy Auditing Techniques

Energy Auditor Role and Activities Basic Inspect HVAC equipment Record nameplate information Review equipment operating schedules and controls Develop a list of energy efficiency measures (EEMs) Present EEMs, savings, incentives, and costs to the client Advanced Above items plus: Log existing power use (status, amps, or kW) Log economizer operation (OAT, MAT, etc.) Directions: -Customize this slide by typing in the specific concepts in relation to the Energy Auditor Role and Activities for your section. -All of the Energy Auditor Role and Activities bullet points must fit within 1 slide only. We recommend using a minimum of 24 point font and a maximum of 32 point font for onscreen text. -The Energy Auditor Roles and Activities bullet points are specific ways the learner can apply knowledge and skills within the field. This focuses on the “action” or application of information rather than the high-level general knowledge presented in the Learning objectives. Energy Auditing Techniques

Energy Auditing Techniques HVAC Fundamentals Heating Offset heat that is lost to the environment Temper ventilation air Ventilating Provide fresh air to building occupants Air Conditioning (or Cooling) Offset heat that gained from the environment Offset heat generated internally Control interior moisture (Relative Humidity) Energy Auditing Techniques

Why is HVAC Important? CA Commercial Sector Electricity Use California Commercial End Use Survey, Itron, CEC-400-2006-005. Energy Auditing Techniques

Primary Purposes of HVAC Comfort for occupants (ASHRAE 55) Temperature Humidity Air movement Fresh air (ASHRAE 62.1 & T24) We need about 15 cfm per person (occupancy) Remove dust, pollutants, contaminants & “bio-effluents” Energy Auditing Techniques

Heat Sources, Sinks & Paths Envelope Solar Conduction Ventilation Air Required for IAQ Internal Loads Lighting Computers Equipment People Energy Auditing Techniques

Energy Auditing Techniques What is a HVAC Zone? A discreet physical area that is conditioned by an HVAC system Heat enters/leaves a zone through Conduction, Convection and Radiation Borders on zones are not always clear, obvious, or tangible Distinct zones in HVAC system marked by separate thermostats Energy Auditing Techniques

Single Zone HVAC System Energy Auditing Techniques

Primary Cooling Technologies Mechanical Cooling Unitary equipment uses a direct expansion (DX) cooling coil accounts for ≈ 67% of all commercial and ≈ 90% of all small commercial this will be our focus today Chilled water systems used in large buildings en.wikipedia.org Energy Auditing Techniques

Unitary HVAC Equipment Unitary refers to equipment where components are matched and rated together. These components include a compressor, condenser, evaporator and fan. Unitary equipment has two main classes: Packaged and Split-System Packaged equipment houses all components in the same enclosure Split-Systems have the compressor & condenser in one enclosure and the evaporator and fan in another, connected by refrigeration tubing Units can be cooling only or cooling with heating All units circulate air, most provide ventilation Energy Auditing Techniques

Unitary Equipment Identification Packaged Unit All components contained in one location Ventilation is introduced through the unit Heating is supplied by a gas furnace, heat pump, electric resistance or a hot water coil http://www.carrier.com Energy Auditing Techniques

Packaged Unit Components Economizer EA OA Cooling Coils SA Heating Coils Filter Supply Fan Condenser Fan and Coils RA T Controls Thermostat Economizer is FREE Cooling Discuss need for barometric relief (weighted) damper at the exhaust air outlet. Fresh air enters at OA. Supply air fan may be “draw through” or “blow though”. SA is supply air or discharge air. Compressor Packaged Unit Building Energy Auditing Techniques

Packaged With Horizontal Discharge http://www.carrier.com Energy Auditing Techniques

Packaged With Vertical Discharge http://www.carrier.com http://www.carrier.com Energy Auditing Techniques

Unitary Equipment Identification Split-System Compressor Component Only No Ventilation provided by unit Only heating is heat pump http://air-condition-units.com Energy Auditing Techniques

Energy Auditing Techniques Split-System www.carrier.com Energy Auditing Techniques

Split-System Examples www.geo4va.vt.edu/A3/A3.htm Energy Auditing Techniques

Split-System Examples www.amvair.com/typesofac.html www.letricharddoit.com/products.htm Energy Auditing Techniques

Energy Auditing Techniques Unclear on the concept Energy Auditing Techniques

Primary Cooling Technologies Mechanical cooling (e.g. DX) energy use can be reduced through the use of economizers and evaporative cooling HVAC equipment is sized for design day loads, but operates the majority of the time under part load (~30-50% average is typical) Energy Auditing Techniques

Energy Auditing Techniques Economizers The economizer cycle refers to using controls and dampers to make use of outside air for “free” cooling when it makes sense Controls used to bring in outside air instead of return air An “economizer” is generally not a single piece of equipment, although people may refer to it as such Energy Auditing Techniques

Economizer Offsetting All Cooling Energy Auditing Techniques

Reduced Mechanical Cooling Energy Auditing Techniques

Energy Auditing Techniques Air Side Economizer Easy to show it’s not working, harder to show that it is working Spot checks not conclusive; must trend data over time Is the economizer bringing in 100% outside air when appropriate? Is the system always providing minimum ventilation air? 80F is the return air temperature Mixed and outside should match between 45F and 55F on all economizers should track up to 78F on integrated economizers Energy Auditing Techniques

Economizer Expected Performance Expected Economizer Operation 80 Minimum outside air 75 70 65 Outside Air Temperature Temperature Return Air Temperature 60 Mixed Air Temperature 55 100% Outside air Supply Air Temperature OA and Mixed air track from 60F to 74F system shuts down to a minimum at 74F but mixed air continues to warm as OA rises due to minimum ventilation requirement shuts down to maintain 60F supply air from cold OA (below 60F) 50 Mixed return and outside air 45 40 1 2 3 4 5 6 7 8 9 10 Noon 11 12 13 14 15 16 17 18 19 Midnight 20 21 22 23 24 Time Energy Auditing Techniques

Economizer Expected Performance Data taken from a study in Southern California Building type is Small Office Percent Loaded is calculated as Compressor Run Hours / by Total Cooling Hours OA and Mixed air track from 60F to 74F system shuts down to a minimum at 74F but mixed air continues to warm as OA rises due to minimum ventilation requirement shuts down to maintain 60F supply air from cold OA (below 60F) Energy Auditing Techniques

Economizers: Implementation Assess economizer operation by observing damper positions for various ambient conditions Use temperature data loggers to better estimate economizer performance Consider add-on economizer kits for existing units with failed economizers Check for adequate relief for outside air Energy Auditing Techniques

Energy Auditing Techniques Evaporative Cooling Cools air via evaporation of water Direct evaporative coolers draw air through evaporative media lowering the temperature and increasing humidity Indirect evaporative coolers use a heat exchanger to reduce the air temperature without increasing humidity; less effective Dampers controlled by economizer: OA, RA & EA. 55 degrees is the supply air temperature 80 degrees is the return air temperature For100% economizer cooling: Economizer control opens damper (cycles) as if it is the first stage of cooling. Minimum ventilation is about 15% (w/ operable windows value can be lower?) For Partial cooling high limits apply: single set-point uses an assumed return air temperature (this is typical case) differential uses two sensors: OA & RA and chooses the cooler: if OA is cooler unit brings in 100% OA if RA is cooler unit brings in 85% RA and 15% OA Needs to be maintained annually. www.muntersamerica.com/ Energy Auditing Techniques

Direct Evaporative Cooling www.wikipedia.com This image has been (or is hereby) released into the public domain by its creator, Buster2058. This applies worldwide. Energy Auditing Techniques

Evaporative Cooling: Implementation Best when high percentage of outside air is required Supply air temperature limited by ambient conditions Direct evaporative cooling is best suited for areas where high humidity won’t cause problems Indirect evaporative cooling can be used when humidity needs to be controlled or mechanical cooling will also be used Direct Evaporative Cooler www.muntersamerica.com/ Energy Auditing Techniques

Primary Heating Technologies Gas Furnaces are the most common source for heat in small commercial applications Range of efficiencies available Forced & Induced draft Electric Heat Pumps provide both heating and cooling Air source Water Source Ground Coupled Electric Resistance Heat Strips can be convenient if natural gas is limited or combustion exhaust is an issue, but Heat pumps are more energy efficient Hot water or Steam coils can also be used, but are generally found in larger systems or systems with many zones highperformancehvac.com Energy Auditing Techniques

Energy Auditing Techniques Air Source Heat Pump Utilizes same vapor compression refrigeration cycle, only now the condenser can be used to add heat to the space Energy Auditing Techniques

Air Source Heat Pump Energy Auditing Techniques oee.nrcan.gc.ca/publications/infosource/pub/h... Energy Auditing Techniques

Air Source Heat Pump Energy Auditing Techniques oee.nrcan.gc.ca/publications/infosource/pub/h... Energy Auditing Techniques

Energy Auditing Techniques Air Source Heat Pump Use air as heat sink Therefore: Efficiency depends on air temperatures (minimum outside operating temperature is ~ 17 °F) Typically smaller systems / single zone Best applicability: mild climates SEERs range from 8 to 16 Title 20 Sets minimum standards by size Also: Water Source Ground Coupled www.fmcs.coop/.../electrical_heat/air_source.htm Energy Auditing Techniques

Field Identification of HVAC Zones Ask facility staff/engineer Review as-built mechanical drawings Inventory the number of thermostats and HVAC units Observe placement of units to thermostats Last resort: go after hours and observe response to changed setpoints Energy Auditing Techniques

Unitary HVAC Nameplate Brand/Model # Age Voltage/Amperage/kW Other information: Rated efficiency Heating/cooling capacity Air flow rate Liquid flow rate Pressure rise Refrigerant Lighting retrofit Optimized “Free” cooling Notice consistent increases June-September (or January lows) Energy Auditing Techniques

It’s not always easy to get the size Energy Auditing Techniques

It’s not always easy to get the size Energy Auditing Techniques

Reinforcement Activity HVAC system exercise… Why are we here? “Packaged units represent cooling for 49% of commercial buildings space” Esource Energy Auditing Techniques

Energy Efficiency Opportunities Retrofits High Efficiency Units Evaporative Cooling Controls Scheduling / reduce operating hours Programmable thermostats Economizer operation Demand control ventilation Operations Reduce cooling loads Keep units maintained www.carrier.com Energy Auditing Techniques

High Efficiency Replacements Package unit replacement isn’t generally cost effective on energy savings alone So where are the opportunities? Older units Early retirement New additions How do we promote it? Comfort Reliability Reduced O&M Costs www.trane.com Energy Auditing Techniques

What to specify: Unitary AC and HP For larger units, use Consortium for Energy Efficiency (CEE) guidelines (www.cee1.org) Specify Tier 1 or 2 Efficiency level www.trane.com Energy Auditing Techniques

What to specify: Unitary AC © 2009 Consortium for Energy Efficiency, Inc. All rights reserved. www.cee1.org Energy Auditing Techniques

What to specify: Heat pumps © 2009 Consortium for Energy Efficiency, Inc. All rights reserved. www.cee1.org Energy Auditing Techniques

Unitary HVAC: Calculations Average Demand kW = (Cooling CapacitykBtu/h) / (SEER) Annual Energy Use kWh/yr = (kW) * (hours per year) Energy Auditing Techniques 48

Evaporative Pre-cooling Lower head pressure by pre-cooling condenser air by direct evaporation New units use microprocessor controls to minimize excess water Water off for outside air temps less than 70°F Evaporative pre-cooling is available as add-on kit to fit many unitary systems Energy Auditing Techniques

Evaporative Pre-cooler Details Energy Auditing Techniques

Evaporative Pre-cooler Details Energy Auditing Techniques

Evaporative Pre-Cooling This data from the Baypoint McDonalds shows that the evaporative pre-cooler operates when the OA temperature is above 75F. It clearly drops the temperature of the air as it exits the media. Delta T as large as 15F Energy Auditing Techniques

Evaporative Pre-cooler Energy Auditing Techniques

Energy Auditing Techniques Control Measures On/off Setbacks Demand Control Ventilation Energy Auditing Techniques

The Opportunity: Controls General Concepts Controls are generally the most cost effective of EEMs Whatever doesn’t have controls probably needs it Controls reduce opportunity for human “enhancements” Limit hours of operation Use to maximize system efficiencies Energy Auditing Techniques

Energy Auditing Techniques Scheduling Mechanical Time Clocks http://www.moonlightinglls.com/ Energy Auditing Techniques

Energy Auditing Techniques Commissioning is key Even with simple equipment Energy Auditing Techniques

Setbacks and Programmable Thermostats Install Programmable Thermostats on all units Scroll through settings during audit www.white-rodgers.com Energy Auditing Techniques

Energy Auditing Techniques Where there’s a will… Energy Auditing Techniques

Setback Thermostats / Scheduling Pitfalls Need to be set correctly, not in “hold” mode Persistence: document with a system manual how things are intended to work Savings Range widely depending on occupancy and use. Typical is 5% to 50%. Demand savings are minimal Non-Energy Benefits Reduced wear on equipment www.white-rodgers.com Energy Auditing Techniques

Web-enabled Thermostats Web-based now available About $170 to $300 each Include ability to monitor remotely www.proliphixstore.com Energy Auditing Techniques

Energy Auditing Techniques For Classroom Control Occupancy-based HVAC controls e.g. Bard CS2000 Energy Monitor “Learns” occupancy patterns No programming required Can control lighting too Outside air off when unoccupied www.proliphixstore.com www.doersales.com Energy Auditing Techniques

Demand Control Ventilation (DCV) Primary purpose of HVAC is to provide adequate ventilation Basic method has been to provide sufficient ventilation for design conditions at all times DCV provides sufficient ventilation based on actual occupancy, rather than worst case Requires continuous monitoring of CO2 as proxy for occupancy Energy Auditing Techniques

DCV: CO2 and Ventilation Rates Energy Auditing Techniques

Energy Auditing Techniques DCV: Implementation All major controls companies support Best practice is to measure outside air and indoor air CO2 concentrations If only indoor concentrations monitored, typical outside CO2 concentration is 400 ppm Controls typically set to introduce OA when indoor concentration is about 500 ppm higher than outside (T-24 requires 600 or better) DCV should be overridden when system in economizer mode Commission to ensure ventilation rates are not compromised Select equipment that automates building purge for overnight buildup of contaminants Energy Auditing Techniques

Load Shifting for Small Commercial “Ice Bear” makes ice at night for use the next day Thermal Energy Storage Capacity = 5 tons Storage = 30 tonhrs Primary savings are in cost of energy due to load shifting Peak kW cost savings May have small energy savings too, depending… www.ice-energy.com Energy Auditing Techniques

Ice Bear Installations www.ice-energy.com Energy Auditing Techniques

Energy Auditing Techniques Ice Bear Performance www.ice-energy.com Energy Auditing Techniques

Operations and Maintenance Commissioning: check set points, schedules and resets Check for controls overrides (e.g. bypassed time-clocks) Filter changes for IAQ Check fixed damper and minimum damper positions Adjust/tighten/replace belts Lubricate rotary equipment Energy Auditing Techniques

Operations and Maintenance (cont.) Clean condenser coils Clean evaporator coils Insulate suction lines Check refrigerant charge Check thermostat/sensor calibration Insulate/seal ductwork Energy Auditing Techniques

O&M horrors from HVACfun.com Energy Auditing Techniques

Small HVAC: Frequent Issues www.energy.ca.gov/pier PIER Buildings Program Design Guide: Big Savings on Small HVAC Systems Energy Auditing Techniques

Reinforcement Activity HVAC calculation system exercise… Energy Auditing Techniques

Energy Auditing Techniques Key Points to Remember Economizers fail frequently and make a big difference in CA climates HVAC units are sized for design-day conditions, but typically operate at 40-50% load Calculating unitary HVAC annual energy use: Energy (kWh/yr ) = [Capacity (kBtu/h) *hours (hr)] / SEER Evaporative pre-cooling can yield big savings in dry climates Record the entire model number from HVAC units DCV provides savings for building with variable occupancies Energy Auditing Techniques

References and Resources PG&E http://www.pge.com/mybusiness/ Database for Energy Efficiency Resources http://www.deeresources.com CEC Guide to Preparing Feasibility Studies for Energy Efficiency Projects www.energy.ca.gov/efficiency Consortium for Energy Efficiency(guidelines for specifying EERs & rough costs/savings) www.cee1.org Energy Design Resources www.energydesignresources.com Washington State University (calculators & other resources) www.energyexperts.org Directions: -Customize this slide by adding additional References and Resources related to this section. -All of the References and Resources bullet points must fit within 1 slide only. Additional References and Resources should be added to the appendix slides. We recommend using a minimum of 24 point font and a maximum of 32 point font for onscreen text. Energy Auditing Techniques

Course Tracker Please take a moment to fill out your Course Tracker excel sheet. Directions: -At the end of each section please remind the learners to fill out the Course Tracker excel sheet. Give the learners an average of 2-3 minutes to fill out the tracker in order to help them capture their knowledge retention during class. -The goal of this Course Tracker learning tool is to provide the learner the opportunity for self assessment of knowledge and documentation of questions at the end of each section. We hope that students will utilize this tool to help them assess what they know and what they may need to brush up on. Energy Auditing Techniques

Energy Auditing Techniques What is that? 1. Split - condenser 2. Packaged unit 3. Exhaust fan 4. Split - evaporator A. Exhaust fan B. Packaged Unit C. Split - evaporator D. Split - condenser Energy Auditing Techniques

Model number: DPS-007-AHCY3 1. Cooling capacity: 7.5 tons 3. Line voltage: 230 2. EER: High? Need more info 4. Heating type: None Energy Auditing Techniques

Energy Auditing Techniques Appendix Energy Auditing Techniques

Energy Auditing Techniques VFD’s for Fans Many systems use variable flow air distribution Fan power laws dictate that power is roughly proportional to the flow rate cubed VFD quality/reliability have improved greatly over time VFD costs have dropped significantly with wider adoption Now required by code for many applications in new construction www.abb.com Energy Auditing Techniques

Why Fans with VFD’s Save Energy This relationships between fan energy and fan flow are taken from the California Energy Commission Guide to Preparing Feasibility Studies and the 1998 Nonresidential ACM Approval Manual. Note that a typical system curve, DOE2 default, is assumed and these relationships are not applicable to all systems. Energy Auditing Techniques

Energy Auditing Techniques A Note on IPLV IPLV is being replaced by IEER Integrated Energy Efficiency Ratio (IEER) IEER Used for unitary equipment ≥ 65 kBtu/h AHRI is dropping use of IPLV because it did not accurately represent efficiencies for units with multi-stage compressors AHRI Standard 340/360 2007 defines IEER as "a single number figure of merit expressing cooling part-load EER…” Incorporated by addendum into ASHRAE 90.1 2007 Not yet adopted by CEE, but soon Energy Auditing Techniques

Energy Auditing Techniques A Note on IPLV Source: http://www.cee1.org/com/hecac/Prog_Guidance_IEER.pdf Energy Auditing Techniques

Energy Auditing Techniques DCV Savings www.energy.ca.gov/pier PIER Buildings Program Design Guide: Commercial Buildings Breathe Right with Demand-Controlled Ventilation Energy Auditing Techniques

Energy Auditing Techniques DCV Savings Case studies show real energy savings with payback periods of 2 years or less www.energy.ca.gov/pier PIER Buildings Program Design Guide: Commercial Buildings Breathe Right with Demand-Controlled Ventilation Energy Auditing Techniques

Water-source Heat Pumps AKA “California Heat Pump” system Uses water loop as heat sink Requires supplemental heat rejection/supply Cooling mode: rejects heat water loop Heating mode: absorbs heat from water loop Efficiency depends water loop temperatures Typically mid-sized commercial systems / multiple zone Best applicability: mild climates Title 20 Sets minimum standards by size McQuay Water Source Heat Pump Design Manual, C:330-1 Energy Auditing Techniques

Water-source Heat Pump Configuration McQuay Water Source Heat Pump Design Manual, C:330-1 Energy Auditing Techniques

Equipment Efficiencies Efficiency: Ratios developed to represent equipment ability to transfer or generate heat relative to the input energy required by that equipment COP - Coefficient of Performance (unit less) What you get divided by what you pay for (in same units) EER - Energy Efficiency Ratio (BTU/Watt-hrs) Fully loaded unit output / electrical input SEER - Seasonal Energy Efficiency Ratio (BTU/Watt-hrs) Average output over a range of conditions / Electrical input IPLV - Integrated Part Load Value (units vary) Weighted average at four part load conditions HSPF - Heating Seasonal Performance Factor (BTU/Watt-hrs) Similar to SEER (same units) but for Heat Pump heating AFUE - Annual Fuel Utilization Efficiency (%) Efficiency of gas furnaces and small boilers measured as the useful energy output divided by the input ή Energy Auditing Techniques

Equipment Efficiencies Energy Auditing Techniques

Energy Auditing Techniques Units Energy Btu = Raises the temperature of 1 pound of water 1 degree Fahrenheit under standard conditions Watt-Hour = 3.413 Btu kilowatt-hr = 1000 Watt-hours = 1 kWh 100,000 Btu = 100 kBTU = 1 therm Rates (units of energy per time) Watt = 3.413 Btu/h (Btu’s per hour) kilowatt = 1000 Watts = 1 kW Energy Auditing Techniques

Energy Auditing Techniques Handy Equations Motor Draw kWh = (hp)(0.746 kW/hp)(%Loaded)(hours)/Efficiency kWh = (FLA)(Volts)(PF)(%Loaded)(hours)(Phase^½) Conduction Btu/h = (U-Value)(Area in sq ft)(Toutside-Tinside) Surface heat gain/loss due to Convection & Radiation Ventilation / Infiltration Btu/h = (1.085)(CFM)(Toutside-Tinside) Radiation Btu/h = Assess qualitatively Energy Auditing Techniques

Energy Auditing Techniques More Handy Equations Efficiency Conversions kW/ton = 12 / EER COP = EER / 3.412 COP = 3.516 / (kW/ton) Heat Transfer in Water Capacity (kBTUh) = GPM * ΔT / 2 Power from hp Power (kW) = 0.746 * Power (hp) Pump power Water Power (hp) = (ft of head) * (GPM) / 3960 Pump Power = Water Power / [Pump eff * Motor eff] Fan power Fan Power (hp) = (cfm)*(SP) / [6354*ήfan* ήmotor] Energy Auditing Techniques

Estimating Savings – Billing Data Estimate amount of bill dedicated to air conditioning Estimate the average efficiency of the existing equipment - SEER Select new efficiency based on available equipment Estimate savings as: or Energy Auditing Techniques

Energy Auditing Techniques Estimating Savings Simplified Full Load Hour Calculation Bin Simulation SPC Software PGE.COM/SPC Order CD Energy Auditing Techniques

Example Calculation: The Problem Existing 5 ton air conditioner is on 24/7 Site is Sunnyvale, CA EER is 10.0 Furnace is 80% efficient Office environment with fan in “on” position (i.e. not “auto”) Propose to schedule M-F, 7 AM to 6 PM Energy Auditing Techniques

Energy Auditing Techniques Here’s the nameplate Energy Auditing Techniques

Example Calculation: Scheduling RTUs Energy Savings from scheduling RTUs off consist primarily of two parts: Reduced fan energy savings Reduced ventilation loads No simple way to take credit for transient effects Energy Auditing Techniques

Example Calculation: Part 1 Fan Savings Fan draw: 208V * (1 phase)^½ * 5.7A * (0.9 PF) = 1.07 kW Hours reduced: Was 24*365 = 8760 hrs/yr Now 11 hrs per day * 365 days * 5/7 ≈ 2868 hrs/yr Savings: 5892 hrs/yr Savings = 1.07 kW * 5892 hrs = 6304 kWh Assuming $0.15/kWh → $945.60 Energy Auditing Techniques

Example Calc: Part 2 Ventilation Savings Use Sunnyvale bin weather data Ventilation load Btu/h = (1.085)(CFM)(Toutside-Tinside) If positive, then cooling load If negative, then heating load Multiply by hours in bin Divide by equipment efficiency Energy Auditing Techniques

Example bin method calc: Energy Auditing Techniques

Energy Auditing Techniques Savings Summary Energy Auditing Techniques