Agenda Introduction Focus of Study Approach Model Data Gathering Preliminary Findings

Introduction Est. 40% of electrical energy used in office buildings is for lighting In most cases, lighting is only needed when the area being lit is being occupied Occupancy sensors uses heat/sound/motion detection technology to identify occupancy Can be used to switch lights on and off as necessary

Introduction

Focus of study Problem Physical Plant is looking into installing occupancy sensors to conserve energy Energy is being wasted because area being lit does not equate lighting actually needed Goal How much energy can be saved under occupancy sensors Perform cost benefit analysis of installing sensors

Approach Compute amount of energy consumed by lighting in base case (no occupancy sensors) Compute amount energy actually needed Estimate the cost of installing and implementing lighting controls

Approach Unit Cost of Energy * ( Energy consumed – Energy needed ) – Cost of installing and implementing lighting control = Amount saved in dollars

Assumptions Unit cost of energy – 6 cents per kilowatts hour Certain type of light fixtures are not suited for occupancy controls (ie. High Intensity Discharge) Certain type of rooms require lighting 24 hours a day Employee satisfaction/dissatisfaction and environmental factors are not considered in cost/benefit

Model: Base Energy Consumption 1.For each room, determine type and number of fixtures 2.For each fixture, calculate unit energy consumption 3.Determining annual energy used per room by multiplying room consumption by the operation time 4.Obtain energy cost by aggregating room consumption and multiplying that by 0.06 dollars

Annual Cost of Energy Consumption: ∑ ( [#of bulbs]*[quantity of fixture] Fixture type * [energy consumed] ) * [unit kwH of bulbs]*[estimated daily operated time]*[estimated weekly operated time]*[estimated year operated time] * 0.06 dollars [Fixture type] i =A,B,H,DG,…etc (different types of fixtures) Different fixture has different # and type of bulbs Model: Base Energy Consumption

Model: Actual Energy Needed 1.For each room, determine type and number of fixtures 2.For each fixture, calculate unit energy consumption 3.Determining annual energy needed per room by multiplying room energy consumption by the percentage of actual usage 4.Obtain energy cost by multiplying annual energy consumption by 0.06 dollars

Model: Actual Energy Needed Annual Energy consumptions: ∑ ( [#of bulbs]*[quantity of fixture] Fixture type * [energy consumed] ) * [unit kwatt-hr of bulbs]*[estimated daily actual usage]*[estimated weekly operated time]*[estimated year operated time] * 0.06 [Fixture type] i =A,B,H,DG,…etc (different types of fixtures) Different fixture has different # and type of bulbs

Model: Determining Cost 1.For each room, identify type of optimal occupancy sensor based on room type and fixture type 2.For each room, identify quantity of occupancy sensors needed, based on room type 3.Calculate the cost of purchasing and installing the occupancy sensor 4.Perform cash flow analysis to determine the timeframe for return on investments

Gathering Data Obtained lighting blue print of physical plant Surveyed physical plant employees to obtain data regarding actual usage Call vendor for lighting control prices

Preliminary Findings Units of energy (kilowatts hour) Electricity costs (dollars) Annual Energy Consumption Annual Energy Needed Amount of Energy Saved

Questions and Answers