Emerado Public School: Energy Audit & Energy Conservation Alternatives Undergraduate Thesis Mechanical Engineering Kristin McKenzie March 15th, 2007.

Emerado Public School: Energy Audit & Energy Conservation Alternatives

Undergraduate Thesis

Mechanical Engineering

Kristin McKenzie

March 15th, 2007

2

Purpose

• Conduct an energy audit of an existing school in Winkler

• Analyzing Manitoba Hydro data

• Modeling the building through a computer program

• Develop fossil fuel energy displacement strategy

• Incorporate renewable energy• Implement in existing

buildings

3

Procedure

#1:Analyze Current

Heating, Ventilation & Air ConditioningSystem (HVAC)

#2:Computer Generated

Building Model

Electricity Consumption

Natural GasConsumption

#3:Conduct Alternative

Energy Analysis

Electricity Consumption

Natural GasConsumption

#4:Research Energy

Efficient HVAC Alternatives

Technical Analysis

CostAnalysis

4

Procedure

#5:Compare Electric &

Natural Gas Consumption

Results

Computer Generated

Actual

Conservation Alternatives

#6:Recommendation

Reduce Costs Reduce ConsumptionReduce

Environmental Impact

Current Heating, Ventilation & Cooling Equipment Installed

HeatingCooling

VentilationHeat Recovery Unit

6

Building Heating• 2 Aerco Condensing Boilers

– High Efficiency• Maximum heat recovery from flue

gases• Heat contained in water vapor is

released through condensing and re-directed into the boiler

– Efficiency of approx. • 95%-98% HHV

– Low inlet water temperature• <140F

– 1 MMBtu/hr

7

Building Cooling

Evaporator

Qout

Compressor

Hot refrigerant liquid

Refrigerant liquid-vapormixture

Expand

Compressed vapor

Cold refrigerant

Cold Water to School

Hot Water from School

CHILLER

A Trane, 70 ton chiller is installed to provide building cooling

Mechanical Work

Qin

8

Building Ventilation• Trane M-Series Climate Control AHU

- Supply: 33,000 CFM- No pre-heat coil- Provides supply air for all school zones

excluding the gym• Trane M-Series Climate

Control AHU- Supply: 5,000 CFM- No pre-heat coil- Provides supply air for

only the gym

9

ExhaustedAir

(from Building)

Heat Recovery Unit – Cycle #1

OUTSIDE

OUTSIDE

Aluminum Cassettes

Aluminum Cassettes Supply

Air(to AHU)

Damper

10

ExhaustedAir

(from Building)

SupplyAir

(to AHU)

Heat Recovery Unit – Cycle #2

OUTSIDE

OUTSIDE

Heated Aluminum Cassettes

Aluminum Cassettes

Damper

Computer Building Modeling & Energy Simulation

Procedure

Results

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eQUEST Procedure

1. Draft building floor plans in AutoCAD

2. Import floor plans into eQUEST

3. Create Building Shells• 9 Shells required to model the

Emerado School

4. Create building zones

within all shells• Multiple shells required within each

shell to model the school

Shell #1

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eQUEST Procedure5. Following procedure completed for all shells:

• Roof, wall, floor, window, door construction• Building operation schedule• Activity areas

6. Specify heating, ventilation and air conditioning equipment and parameters

Shell #1:Main Level

Shell #9:Upper Level

Shell #2:Shell #3:

Shell #4:

Shell #5:

Shell #6:Shell #7:

Shell #8:

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Simulation Results

Heating Load

Cooling Load

(MBtu/hr) (MBtu/hr)

System #1 1697 761

Main AHU

System #2 202 150

Gym AHU

System #3 151 0

Change Rooms

TOTAL 2049 911

Actual Aerco Condensing Boiler Input:1000 MBtu/hr * 2 = 2000 MBtu/hr

eQUEST Calculated Required Input:2049 MBtu/hr

Actual Trane Chiller Input:70 tons (840 MBtu/hr)

eQUEST Calculated Required Input:911 MBtu/hr

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Simulation ResultsINVERSE EFFICIENCY CURVES

80

82

84

86

88

90

92

94

96

98

100

60 80 100 120 140 160 180

TH

ER

MA

L E

FF

ICIE

NC

Y

25% & 50% Input

75% Input

100% Input

RETURN WATER TEMP (deg F)

Building Energy Conservation Alternatives

Biomass

BioFuel Boiler

Absorption Chiller

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Biomass

Biomass Btu/lb

Wheat Straw 7528

Corn Cobs 8070

Alfalfa 6934

Sunflower Hulls

7474

Soybean Hulls

6660

• Biomass– living or biological material that has

recently been living, providing renewable energy

• Plant or animal matter• Forest waste• Municipal waste• Food processing waste

– Form of stored solar energy that is developed when sun is captured through the process of photosynthesis

– Grown from:• Hemp, corn, willow, sugarcane,

switchgrass

• BioFuel• Fuel derived from Biomass

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Locally Produced BioFuel

• Local producer in Manitoba– Prairie BioEnergy

• Produces– Compressed biomass cubes made of a

mixture of wood by products and flax– Energy Content

• 7900 Btu/lb

– Density• 33 pounds/ft²

– Moisture Content• Approx 5%-6%

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Locally Produced BioFuel

• Product Handling– Product Displacement

• Conveyor• Large screw auger

– Storage• hopper

– Product must be kept dry• Delivery System

– Slow speed auger• Combustion System

– Ability to handle ash

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Pelco Hot Water Boiler

• Locally distributed hot water boiler• Solid fuel fired boiler• Automatic feed auger• Automatic ash removal system

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AnalysisCurrent Design

New ‘BioFuel’ Design

Building Heating Requirements

Approx 2,000,000 Btu/hr

Aerco Condensing Boiler #1

1,000,000 Btu/hr

Aerco Condensing Boiler #2

1,000,000 Btu/hr

Pelco Hot Water Boiler

2,500,000 Btu/hr

TOTAL 2,000,000 Btu/hr

4,500,000 Btu/hr

If required, condensing boilers will operate at part capacity

Pelco HW boiler will run at near full capacity

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Analysis

40 tonstorage

• Prairie Fuel Cube Energy Content:– 7900 Btu/lb

• Prairie Fuel Cube Moisture Content:– 5%-6% of total mass

• BioFuel Boiler Input: – 2.5 MMBtu/hour

• Required BioFuel: – 2,500,000*6% + 2,000,000 = 2.6 MMBtu/hour

• Required biomass: – 335.4 lb/hour– 8,050 lb/day– Approx 4 tons/day

•

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Cost Comparison• NATURAL GAS

– Blended Rate• $0.3810/m³

– HHV• .035GJ/m³

– Energy Input• 2.5 MMBtu/hr = 2.6

GJ/hr– Required Volume NG

• 75.36 m3/hr– Hourly Cost

• $29/hr

• BIOMASS– Cost

• $75/BDT– HHV

• 7.4GJ/m³– Energy Input

• 2.5 MMBtu/hr = 2.6 GJ/hr

– Required Biomass• 0.14 tons/hr

– Hourly Cost• $11/hr

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Cost Comparison

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Absorption Chiller

Evaporator

Qin

Compressor

Hot refrigerant liquid

Refrigerant liquid-vapormixture

Expand

Compressed vapor

Cold refrigerant

Cold Water to School

Hot Water from School

ABSORPTIONCHILLER

Heat Input From Boiler

**Trane 100 ton absorption chiller, approximately $155,000 Canadian Dollars

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Is Biomass Feasible?

Pelco Hot Water Boiler

Prairie BioEnergy

DisplacementEquipment

Absorption Chiller

Potential Manitoba Hydro Chiller Incentives

+ + +

+ =

•Renewable energy Resource

•Eliminates fossil fuelDependency

•Healthier for theEnvironment

•Reduced fuel costs

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Conclusion

• Gained experience through studying and analyzing the current HVAC system installed

• Biomass provides an environmentally friendly, renewable resource, and readily available fuel is approx 1/3 of the cost of natural gas

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Further Work

• Energy Conservation Alternative– BioFuel Boiler

• Cost Analysis

– Solar Panels• Technical Analysis• Cost Analysis

• Design Recommendations

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Acknowledgements• Dr. E. Bibeau, P. Eng

– Thesis Advisor

• Dr. P. Zanetel, P. Eng– Thesis Advisor

• Robert Bisson, P. Eng– Public Schools Finance

Board– Mechanical Engineer

• George Marchildon, P.Eng– Public Schools Finance

Board– Mechanical Engineer

• Terry Silcox– Manitoba Hydro

• Stephane Gauthier– Prairie BioEnergy

• Gerry Porter– Entropic Energy

Questions???