sustainable building systems - thayer school of …d30345d/courses/en… · ·...

Presentation to:Dartmouth CollegeJanuary 21, 2010

van Zelm Engineers10 Talcott Notch RoadFarmington, CT 06032(860) 284-5064 www.vanzelm.com 1

Sustainable Building Systems

David Madigan

Thayer School of EngineeringDartmouth College

May 8, 2014

VANZELME N G I N E E R S


• Energy use in Buildings• Air Systems

• Heat recovery• Underfloor air distribution (UFAD)• Dedicated outside air systems (DOAS)• Displacement ventilation• VAV kitchen hoods

• Hydronic systems• Hydronic heating/cooling• Sensible-only cooling terminals

• Primary energy systems• Cogeneration• Ground source heat pumps (GSHP)• Renewable energy systems

Presentation Overview





• USA uses 40% of World-wide Energy Flows and Generates 33% of CO2 and Associated Pollutants World-wide

• Buildings use 1/3 of Total US Energy and 2/3 of Electricity• Buildings account for 30% of Total U.S. Greenhouse Gas

Emissions

Energy Use in Buildings


Total Energy Cost

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

FY Ending

An

nu

al

Co

st

vs

. B

ase

lin

e (

199

5)

Thermal

Electric

Baseline 1995 = 1.0

Electric Cost > Double

Thermal Cost > Quadruple

Campus Energy Costs


Typical Building Energy Usage


* Electricity Cost: $3.50 - $4.50 / 100,000 Btu* Thermal Cost: $1.50 - $2.00 / 100,000 Btu

Building Type Energy Use Cost / sf

Campus Average : 150,000 to 250,000 Btu/sf $3.00 - $5.00

Modern “Baseline” : 80,000 to 90,000 Btu/sf $2.00 - $3.00

Modern “State-of-the-Art” 30,000 to 40,000 Btu/sf $0.75 - $1.50

Inefficient Lab Buildings: 300,000 to 500,000 Btu/sf $7.00 - $12.00

“State-of-the-Art” Labs < 100,000 Btu/sf $2.00 - $3.00




Typical Building Energy UsageDormitory Cost

Breakdown


Lights$23,646

24%

Plug Loads$25,411

26%

Fans$7,059

7%

Space Cooling$12,349

12%

Pumps & Aux$8,619

9%

Heat Rejection$205 0%

Domestic Hot Water

$8,038 8%

Space Heating$13,978

14%

Lights20%

Plug Loads21%

Fans6%

Space Cooling11%

Pumps & Aux8%

Space Heating20% Heat Rejection

0%Domestic

Hot Water14%

Dormitory Energy-UseBreakdown


• 200 + Buildings

• 250 Acre Core Campus

• 6+ Million Square Feet

• Central Heat Since 1898 w/ Co-generation since 1911

• Fuel Oil #6

• 3 Backpressure turbines. Makes around 40% of campus electricity

• 5 miles of underground steam piping

• District Chilled Water. Four plants.

• Centralized Digital Building Controls

Dartmouth College Background




Historical Oil Cost and Usage – Last 20 Years

0

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4,000,000

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8,000,000

10,000,000

12,000,000

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Oil

Cos

t ($

)

Gal

lon

s

Oil Consumption and Cost

Oil Consumption (gals) Oil Cost (S)

And Rising Energy Use - Oil


Historical Electrical Cost and Usage – Last 20 Years

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2,000,000

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4,000,000

5,000,000

6,000,000

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40,000,000

50,000,000

60,000,000

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1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Electric Cost ($)

kWH

Electric Consumption and Cost

Total Electric Consumption (kWH) Purchased Electric Cost ($)

And Rising Energy Use - Electricity




• Gross Square Feet14% Growth

• Air Conditioned GSF 41% Growth

• Air Conditioned Growth from 33% to 50% of Campus GSF

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

2005 2006 2007 2008 2009 2010 2011 2012

To

tal G

SF

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

2005 2006 2007 2008 2009 2010 2011 2012

Air

Co

nd

itio

ned

GS

FDartmouth’s Growth 2005-2012

Expanding Conditioned Area


• Increasing building area and conditioned space requires additional campus utility capacity

• Boiler Plant expansion

• Chiller Plant(s) construction

• Long term energy planning has started to show results.

• “Business as Usual” will not achieve goals for reduction in energy use / cost and emissions

• Decisions based on short term energy cost / payback will not provide long term value to institution

• Need a total cost accounting approach to energy investments

Dartmouth Energy Picture




Embodied Environmental Impacts


“Over time, environmental impacts from high energy use may far outweigh all other (environmental ) factors.”

- Environmental Resource Guide

0 5 10 15 20 25 30 35 40

Years

0

1000

2000

3000

4000

5000

6000

7000

8000

9000S

ourc

e K

Btu

/sf

Operating Energy

Embodied Energy


Sustainable Design Process

Building Shape

Orientation

Glass location

Glass area & type

Insulation values

Thermal mass

Building Volume

Passive Solar

Daylighting

Lighting

HVAC

Heat Recovery

Optimized Ventilation

Building Automation

Domestic Hot Water

Electricity

Steam

Hot Water

Chilled Water

Cogeneration

Solar Thermal

Photovoltaics

Bio-Mass

Schedules

Controls

Maintenance

Setpoints

Windows

Equipment

Education

Commissioning

Re-commissioning

Minimize load as a first priority.

Use efficient, cost-effective systems

Produce and distribute energy

efficiently

Operate the building well

Building design and program fixes

the load

Primary Energy Systems supply

energy to buildings

Efficient building systems meet

the load

People run the systems




Building Air Systems Evolution


Pre - 1900 -- Operable windows, steam heat

1900 – 1940 -- Exhaust, operable windows, steam heat

1940 – 1960 -- Single zone, constant volume AC, steam heat

1960 – 1980 -- Multiple zone, constant volume AC, HW reheat

1980 – 2000 -- Variable air volume systems, HW heating

2000 - ? -- DOAS, Heat recovery, hydronic heating and cooling, UFAD.


HCCCFilterSupply Fan

Return Fan

VAV Box

Return Damper

Exhaust Damper

Outside Air Damper

Traditional Recirculating VAV System

Supply Air

Return Air

TT

Toilet Exhaust





Airside Heat Recovery


• Applicable to nearly all air handling systems

• Best economics obtained for:

• 100% outside air systems

• Long hours of operation

• Labs, classrooms, locker rooms and pools

• Substantial peak load reductions allows savings in boiler and chiller equipment costs.

• Latent heat recovery allows substantial savings in cooling costs.


Airside Heat Recovery Options

Runaround Coils• Pros

• Greatest airstream separation, flexibility

• Simple Technology• Easily cleaned• Minimum space requirements

• Cons• Lowest recovery efficiency (55%)• High parasitic loads for pumping• No latent transfer• Poor cooling performance• Most moving parts, highest

maintenance VANZELME N G I N E E R S

Cooling and Dehumidification Coil

Outside

Air

SupplyAir Fan

To Labs

From

LabsEnergy

Recovery Coil

Energy Recovery FromExhaust Air Loop

Exhaust

Air Coil

ExhaustFan

ExhaustAir






Plate Heat Exchangers and Heat Pipes• Pros

• Good airstream separation• High sensible efficiency (75%)

sometimes latent available• Heat pipes easily cleaned• High reliability – no moving parts• Indirect evaporative cooling possible

• Cons• May be space intrusive• Generally no latent transfer• Plate heat exchangers difficult

to clean




Heat Wheels• Pros

• Highest sensible and latent efficiency (80%)

• Excellent cooling performance• Significant reductions in peak

heating and cooling loads• Purge minimizes carry over

• Cons• Airstream separation issues• Can be space intensive• Operational issues




Heat Recovery Systems


Type Effectiveness Carryover Reliability Airstream Proximity

Comments

Sensible Latent

Enthalpy Wheel

70%-80% 65%-75% Yes

(< 0.05%)

Average Required Greenest

Heat Pipe 60%-75% 0% None Highest Required Contains refrigerant

Plate HX 60%-75% 0% None Highest Required

Runaround Loop

50%-60% 0% None Average Not Required

Glycol or Refrigerant

Options Summary


Heat Recovery System EconomicsDartmouth Life Sciences Building

• 175,000 sf Laboratory Building• Peak airflow: 107,000 cfm• First Cost Savings: Enthalpy wheels

– Cooling: 269 tons @ $2500 = $672,500– Heating: 7813 MBH @ $30 = $234,390

$906,890

• Heat Recovery System cost:– 107,000 @ $6 / cfm = $642,000– 1500 sf @ $200 = $300,000

$942,000

• Annual Energy Savings: $600,000 + VANZELME N G I N E E R S




Dedicated Outdoor Air Systems (DOAS)

• Concept:

Separate the control and load associated with ventilation air supply from local envelope and internal loads.

• 100% outdoor air supply system – usually packaged with air/air heat recovery

• May be Sized for diversified ventilation load

• Deliver DRY cooling or neutral air to occupied spaces

• Enables use of highly efficient and high comfort terminal systems (Radiant, chilled beams, valence, etc.)



DOAS System Schematic


100% OA DOAS Unit W/ Energy Recovery

Cool/Dry Supply

Parallel Sensible Cooling System

Building With

Sensible and Latent

cooling decoupled

Exhaust





Exhaust Fan

4 Pipe Chilled Beam

Exhaust Damper

Outside Air Damper

Dedicated Outdoor Air System

Return Air

Toilet Exhaust

FilterHeat Wheel

2 Pipe Chilled Beam



DOAS System vs. VAV

Example: 20,000 sf building – 200 People


Traditional VAV System• 1 CFM/sf = 20,000 CFM

Total Supply Air

• 0.75 HP/1,000 CFM = 15 HP fan energy

• 32 Sq Ft duct area (Supply and Return)

• Varying air volume to maintain space comfort

DOAS System• 20 CFM/person = 4,000

CFM Total Ventilation Air

• 0.75 HP/1,000 CFM = 3 HP fan energy

• 8 Sq Ft duct area (Supply and Exhaust)

• Constant ventilation air only supply




• Can be used for virtually any occupancy type• Both new construction and renovation projects• Highly effective when combined with ventilation air

reset through CO2 sensing control to track occupancy• Improved energy efficiency over all air based systems

with better comfort and control.

• Must consider air delivery method:

• Underfloor

• Displacement Ventilation

• High Induction Diffusers

• Greater assurance of proper ventilation volume

DOAS System Applications



Displacement Ventilation

• Objective – deliver clean air to the “breathing zone”

• Avoid mixing clean supply air with contaminated room air

• Does not necessitate an underfloor delivery system

The Breathing

Zone

Supply Air

Exhaust Air

3’ Above Floor

7’ Above Floor

63-65 deg F.

75-85 deg F.

Raised Floor

Ceiling or Structure Above

Hard SlabVANZELME N G I N E E R S




Displacement vs Traditional Supply


Displacement:Clean air enters space low and rises through breathing zone

Overhead Mixing Supply:Clean air enters space from overhead and mixes with contaminated room air



Exhaust Fan

Return Damper

Exhaust Damper

Outside Air Damper

Underfloor Air Distribution System

Return Air

General Exhaust

Exhaust Fan

Heat Wheel

Supply Air

Baseboard RadiationVANZELME N G I N E E R S




Displacement Ventilation – Applications

Consider for:

• Open Offices

• Enclosed Offices

• Classrooms

• Tiered Lecture Halls

Don’t consider for:

• Laboratory Spaces

• Residential Units



Hydronic Heating / Cooling Systems

Benefits over Air Based Systems:

• Lower transport energy requirements

• Greatly reduced space requirements

• High degree of flexibility

• Improved environmental control

• Excellent acoustical performance

• Applicable to essentially all occupancies

• Can be lower in cost





Hydronic vs. Air Based Energy Transport

To transport 100,000 Btu / hr:


30”

16”

Supply Return

Air Based Hydronic Based

1 ½”

CHWS CHWR

Fan Horsepower: 4.2 hp

Annual Electric Cost $2711

Pump Horsepower: 0.3 hp

Annual Electric Cost $193

16”

30”


Hydronic Heating/Cooling Systems

Application Issues:

• Typically combined with DOAS

• Condensing verses non-condensing terminals

• Lack of airside economizer

• Chilled water temperature optimization

• Condensation control

• Integrated vs. separate heating/cooling terminals

• Two pipe versus four pipe distribution





Hydronic Heating/Cooling Systems

Terminal Types

• Condensing:• Fan coil units

• Valence units

• Non-condensing:• Radiant ceilings

• Radiant structural slabs

• Passive chilled beams

• Active chilled beams



Sensible Only Cooling Terminals

Concept:

• Once you have delivered Dry ventilation air to meet code Outdoor Air requirements ------ Remaining load is all Sensible• Solar Gains

• Internal Gains

• Therefore, you do not need to condense water vapor from the air (Latent load) and can use local sensible only (non-condensing) hydronic cooling terminals.

• The cooling system then looks just like the simplest of heating systems, H&V AHU with perimeter radiation





Application:

• Must be combined with a DOAS system

• Control solar, envelope and internal loads

• Select most effective and appropriate cooling terminal

• Consider implications of operable windows




Radiant (Cooling) Ceiling Panels:

• Output is based on surface area of panels

• May need to cover a significant % of ceiling (or walls) with panels to meet loads (40-60%)

• Best applied where there are modest solar and internal loads• Private offices

• Interior open spaces

• Same panel can also be used for heating

• Highest level of occupant comfortVANZELME N G I N E E R S




Radiant Panels




Active Chilled Beams:

• Convection is aided by supply air which induces greater flow across chilled beam coil

• Active Beams can be exposed (pendant), surface, or flush to ceiling mounted.

• Higher output than passive chilled beams are possible

• Low or no capacity without supply air

• Can also be used effectively for heating (while air system operating)

• Can have noise or draft issues if mis-applied





Active Chilled Beams



Chilled Beam Applications






Condensation / Humidity Concerns:

• Must maintain Dry DOAS supply air

• Must control infiltration

• Must control internal sources of moisture

• Provide local condensation sensor


Cogeneration


• Combined Heat and Power (CHP/Co-generation)

• Economically viable in some form for nearly all campus heating/cooling systems.

• Requires careful analysis to justify capital expenditure and optimum approach.

• Can be applied to central or distributed systems.

• Provides significant source of standby power

• Potential for major environmental benefits




Co-Generation System Options


• Combined Heat / Power Systems• Use waste heat from electric generation for thermal loads• Use waste thermal loads for electric generation

• Central Plant Configurations• Backpressure Turbine (bottoming cycle)• Gas Turbine (topping cycle)• Reciprocating Engine (topping cycle)

• Distributed Plant Configurations• Fuel Cell• Reciprocating Engine• Micro-Turbine


Conventional Energy System


BOILER(Efficiency = 83%)

STEAM TURBINE(Eff. = 42%)

GENERATOR(Eff. = 94%)

DISTRIBUTION SYSTEM(Eff. = 90%)

CONDENSER

BOILER(Efficiency = 80%)

100Units 30

Units35

Units

33

Units

50Units

High Pressure Steam

83 Units

Heat to Process40 Units

150 Fuel Source units yields:

30 units of electricity and

40 units of thermal energy

Overall Efficiency: 46%




Topping Cycle Cogeneration System


GENERATOR(Eff. = 90%)

100Units

39

Units

35Units

ENGINE(Efficiency = 39%)

EXHAUST GASHEAT EXCHANGER

JACKET WATERHEAT EXCHANGER

Steam to Campus

Hot Water to Campus40 Units


35 units of electricity and

40 units of thermal energy



10Units

Bottoming Cycle Cogeneration System


BOILERBACKPRESSURE

STEAM TURBINE

GENERATOR100

Units

High Pressure Steam

83 Units


10 units of electrical and

70 units of thermal

To Campus Heating System


70 Units




Cogeneration Systems


• Cogeneration Options – Topping Cycle

• Primary electrical, thermal byproduct

• Gas turbines, reciprocating engines, fuel cells

• High ratio of electrical to thermal

• Wide range of sizes: 30 KW to 100 MW+

• Consistent year round output possible

• Standby power benefits



Cogeneration Systems

• Cogeneration Options – Bottoming Cycle

• Primary thermal with electrical byproduct

• Steam turbine, thermal cooling

• High ratio of thermal to electrical output

• Sizing limited by thermal load

• Electrical output tracks thermal –may not be available in warm weather




Distributed Systems



Cogeneration Summary

Campus Cogeneration Projects

Institution Type SizeFirst Cost

First Year Saving

Annual ROI

CO2

Savings

Amherst College

Gas & Steam

Turbines1.8 / 3.1 MW $6.8 M $615,000 16% 6,600 T/yr

Mount Holyoke College

Gas Recip.

1.8 MW $5.1 M $410,000 12% 8,700 T/yr

Smith College

Gas Turbine

3.5 MW $10.9 M $1,400,000 18% 16,400 T/yr

Will reduce net carbon emissions by 30,000 tons/year (30%)




Ground Source Heat Pumps


• GSHP Geothermal?

• GSHP – What it is?“Electrically driven mechanical refrigeration

system using the earth or groundwater to draw heat from, or reject heat to, in order to improve system efficiency”

• Consistent earth temperatures year round allow high system efficiency throughout the year

• Coefficient of Performance (COP)• Energy output / energy input (efficiency)• COP for GSHP – typically 3-4




Heat Rejection Options

• Closed Loop• Vertical shallow wells (250’)• Horizontal trench

• Open Loop• Standing column deep well (1500’)• Extraction / reinjection wells• Ponds / lakes / ocean

• Capacity• Horizontal trench• Vertical shallow wells 2-3 tons / well• Standing column 30-40 tons / well






• Pros:• High efficiency compared to distributed building heating /

cooling systems• All electric – no local fuel required• No external heat rejection device required

• Acoustics, Aesthetics• Perceived as very “green”

• Cons:• May not be more efficient than campus

heating / cooling systems.• First cost may be high• Underground piping & wells – complexity, space• Heating / Cooling electronically dependant




Good Applications:

• Locations not served by high efficiency campus heating/cooling systems

• Applications using radiant slab heating/cooling• Low temp HW, high temp CHW

• Applications with moderate, consistent loads

• Locations with substantial developed sites




Seasonal Cooling Efficiency

Cooling SourceI PLV

Kw / tonSEERUnits

COPOutput / Input

LT Chiller (42°LWT)

0.40 23 8.6

HT Chiller (58°LWT)

0.29 40 11.8

Packaged Air Cooled Chiller (42°F)

0.73 15.9 4.7

Ground Source Heat Pump

0.85 13.7 4.0

Rooftop DX AHU

1.14 10.3 3.0


• Many commercially available options

• Reduce GHG & pollutant emissions

• Minimize dependence on foreign oil

• Protection against increasing fuel prices

• Reduces trade imbalance, stimulates domestic economy

• Attractive life cycle economics

• Visible commitment to environmental stewardship

Renewable Energy





• Solar Thermal

• Solar Electric

• Daylighting

• Wind

• Biomass

• Hydro

Renewable Energy Options


Low-Impact Hydro

Photovoltaics

Biomass

Wind


• Conservation preferable over renewable energy• Usually better economics

• Even renewable energy has environmental consequences

• Conservation measures result in reduction of usage and peak loads

• Conservation and renewable energy complement one another• Renewable energy capital intensive

• Conservation reduces capital investment by limiting peak loads

• Implement renewable energy systems after making maximum use of conservation options

Conservation vs. Generation





• Solar energy is the basis for essentially all renewable energy sources

• Solar energy incident on earth annually:• 160 times the world’s proven resources of fossil fuels

• 15,000 times the world’s annual use of energy

• Solar can be utilized directly or indirectly

Solar Energy



• Active Solar Heating

• Passive Solar Heating

• Solar Thermal Engines

• Daylighting

Solar Energy




• Highly effective in residential buildings, educational and small commercial buildings

• Limited applications in “traditional” large scale buildings• Can be effective as part of an integrated design process • Coordinate with daylighting design• Performance improved with massive construction• Commercial applications to consider

• Solar heated entry vestibules• Solar induced natural ventilation• Double wall facades

• Optimized passive solar features can produce excellent economics

Passive Solar Design



• Dark surface with high absorptance gathers full spectrum of solar radiation

• Heat is drawn away by working fluid – usually glycol / water

• Glass and/or selective surface used to minimize Conduction and re-radiation losses

• Efficiency dependant on collector design working temperature and ambient temperature– Lower Fluid Temperature = Higher Efficiency

– Lower Ambient Temperature = Lower Efficiency

Solar Thermal Collectors





Collector Types


• Domestic Hot Water Heating

• Pool Heating

• Space Heating

• Make-up Air Preheat

• Thermal Based Cooling

Active Solar Thermal Systems





• Low temperature operation allows high collector efficiency, year round loads

• Storage requirements dependent on use profile

• Back-up heating required – inexpensive

• Good application for dormitories, athletic centers, dining facilities, laundry, healthcare

• Limited Loads in Commercial Buildings

• Excellent Economics if Displacing Electric Heat

Application Considerations

Domestic Hot Water



• Electricity production directly from sunlight

• Utilizes photon energy in sunlight to promote electrical current flow

• Relies on semi-conductor effects in specialized materials

• Think of PV as “Solar Energy Converter Systems”

Photovoltaic Energy Concepts





Thin Film on flexible substrate

Thin Film on glass substrate

Mono-crystallineMono-crystalline

Poly-crystalline

Types of PV Modules



Crystalline PV Modules

• Output: 10-12 watts/SF

• Efficiency: 12% - 18%

• Color: blue

• Module sizes: 5 watts –300 watts

• Reduced efficiency under hot conditions

• Longer track record in field

Thin Film Modules

• Output: 5-7 watts/SF• Efficiency: 6% - 8%• Color: gray to black, deep

blue• Module sizes: 5 watts – 120

watts• Less efficiency drop under

hot conditions• More efficient in low light

conditions

Crystalline vs. Thin Films





Grid-tied System

PV Components


To Building Uses


Building Integrated Photovoltaics - BIPV





Custom Glass Laminates

BIPV - Skylights


Uni-Solar Standing Seam Metal Roof

BIPV Roofing Products




Site Performance Estimates

Overall Efficiency

Performance

Kwh/meter2 /yr

Denver, CO 11.4% 163

Shreveport, LA 11.1% 145

Atlanta, GA 11.2% 151

Syracuse, NY 11.6% 126

PV Regional Performance



Solar Thermal PVPanel Efficiency 60 – 80 % 12 – 16 %Panel Cost $12 – 18 /s.f. $40 – 50 / s.f.Peak Output 50 – 60 w/ s.f. 8 – 12 w/ s.f.System Cost $80 – 100 / s.f. $80 – 100 / s.f.

$1.25 – 2.00 / w $6 – 10 / wAnnual Output 65 – 85 kwh/s.f./yr 12 – 16 kwh/s.f./yr

Offset Energy Cost ($15/mmbtu) / ($0.15 kwh) $0.15 /kwh

Annual Savings $4.00/s.f. / $11.00/s.f. $2.00/ s.f.Simple Payback 15 – 20 yrs./ 6 – 10 yrs. 30 – 40 yrs.ROI 8% / 18% 4%

Solar Thermal / PV Comparison




• Solar Resource Used to Offset Highest Cost Electricity

• Technology Well Developed

• Allows Reduced Cooling Loads Also

• Can Help to Downsize HVAC Systems

• Glazing Optimization by Exposure

• Need to Control Excess Solar Heat Gain

• Best Implemented as Part of an Integrated Design Process

• Can Be Highly Cost Effective

• Improves Indoor Environment

Overview

Daylighting



• Window and Shading Devices

• Skylights and Clerestories

• Atria and Reflectors

• Light Tubes

• Focusing Fiber Optic Technology

• Daylight Dimming Systems

Daylighting Technologies




Daylighting Technologies


• Energy from plant matter or other biological material

• Generation of electricity and/or thermal energy

• May be utilized directly….• Feedstock combustion

• …or Indirectly• Gasification• Distillation

Biomass





• Solid Biomass• Wood Chips

• Wood Waste

• Agricultural Waste

• Biogas• Landfill Gas

• Biogas from Animal Wastes

• Gasification of Solid Biomass

Biomass



• Application is very facility specific

• Most feasible with on-site or nearby fuel source• Landfills

• Livestock and agricultural facilities

• Sawmills

• Mountain locations near forest thinning

• Economics can be very favorable – Fuel is inexpensive compared to fossil fuels

Biomass





• Liquid Bio-fuels / Bio-diesel / Yellow Grease• Liquid fuel made from agricultural crops or wastes

• Fuel source for vehicles or stationary applications

• Potential use in place of diesel for backup generators, cogeneration

• Need to confirm compatibility with equipment

Biomass



• Biomass is renewable energy…

• Biomass is largely carbon neutral……if sustainably harvested & utilized

• Is it “Clean Energy”?

particulates, combustion, emissions of NOX

• Cleaner then fossil fuels, not as clean as solar or wind.

Biomass





• Energy in wind captured with a turbine

• Wind speed is critical; power varies with the cube of the speed

• Efficiency typically increases with turbine size and tower height

Wind Power



• On-Site generation is possible

• Small turbines available for commercial applications, down to less than 1 kW

• Technology is available and proven

Wind Power





• Application is very location specific

• Ideal site is open without surrounding buildings to block wind

• Varying wind resources by location

• At a good site, the financial performance can be much better than PV

• However, Limited Application in campus environment• Location and site specific

• Aesthetic issues – more conspicuous than PV

• Consider off-campus development

Wind Power



Wind Power




• Resources:• Wind Maps Available from National Renewable Energy

Lab: www.nrel.gov

• Information on Small-Scale Wind Systems from American Wind Energy Association: www.awea.org

• OEMC has Anemometer Loan Program to Measure Resource at a Site: www.state.co.us/oemc

Wind Power



• Fuel Cell Technology is not new (1950’s)

• Conversion of source fuel to electricity through chemical process rather than mechanical

• No traditional combustion used – no typical products of combustion

• Source Fuel – almost anything with hydrogen

• Fuel “reforming” is required unless pure hydrogen is available

General

Fuel Cell Technology





• Most common fuel – Natural Gas(CH4 – Methane Based Fuels)

• High conversion efficiencies possible (like diesels)

• Emissions– CO2 (Fuel Reforming)– Fuel impurities– H2O

• Waste heat available for use

General

Fuel Cell Technology


• Energy not truly “Renewable” if fueled on Natural Gas

• Some states allow renewable energy incentive for fuel cells using any fuel

• Renewable fuel options– Bio Derived Gas

– Landfill Gas

– Solar / Wind Derived Hydrogen from Water

– Bio-fuel Derived Hydrogen from Water

Fuel Cells – Renewable Energy?




Maintenance Issues

• Stack Replacements – 40,000 hours?

- 3 to 5 years

• 20+ Year Life Expectancy – Balance of Plant Components

• Maintenance Costs 0.005 – 0.015 $/kWh

• “High-Tech” Maintenance Required

Technology Overview

Fuel Cells



• Phosphoric Acid (PAFC)

• Proton Exchange Membrane (PEMFC)

• Molten Carbonate (MCFC)

• Solid Oxide (SOFC)

Technology Overview

Fuel Cells





• High First Cost at Present• $4000 - $6000 / kW

• With Mass Production, Prices Could Drop Substantially• $1000 - $2000 / kW or Less

• Clean / Uninterruptible Power Applications can Improve Economics

• Cogeneration Improves Economics

• Bio-Derived Fuels can be Expensive

• Depends on Hydrogen – the ideal fuel if only we had some and it weren’t so hart to store

Fuel Cell Economics


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