3/7/2014 GAOI 2014

Kirk Mescher, PE, LEED® APMatthew Slager, PE LEED® AP

Ground Source Solutions for

Architects and Engineers

What is in it for us?

• High Efficiency system• Energy efficient / Green solutions for

clients• Gaining technical high ground

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What not to do

• Use rules of thumb• Turn all of the responsibility over to a

contractor• Design it like a 2 pipe fan coil system• Let others sign the ground loop

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Architects and Engineers Should Embrace Ground Source

• These systems are Simple• They have a very low life cycle cost

– Low cost of maintenance– Low operating cost– Long lived system value

• Owners are requesting high efficiency system

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Why• Should architects get involved with ground

source heating and cooling solutions?– Cannot see anything on the exterior of the

building– Clients are demanding high value buildings

and systems– When properly applied, outstanding energy

efficiency– Seasonal energy recycling

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Why

• Should Engineers get involved with ground source heating and cooling solutions?– Lowest life Cycle Cost– Energy efficient– Simplicity – Requires Engineer to understand building

operation to properly design– Modular design

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Utility Rates

• Electricity Production is Diversified– Lower Inflation– Lower Risk

• Electric Rates are Historically More Stable• Utility Bills are More Predictable

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Getting Started:

• References– ASHRAE CHAPTER 34 – HVAC

Applications Volume– ASHRAE TC 6.8 Geothermal Heat Pump

and Energy Recovery Applications– Various Journal articles

• Attend seminars like this

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Recommended ASHRAE Design Guide for Commercial and Institutional Buildings

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Ground Source

• What is it?– Efficient system connected with the

ground?• Heat recovery system?

– Recover energy from season to season?

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The earth absorbs nearly half of the sun’s energy.

Ground Source Energy

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Ground Source“The Efficiency Silver Bullet”

• The most efficient HVAC system there is!!!

• It works everywhere!!!• XXX m/kW (xx ft/ton) is adequate

everywhere!!!

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Geo-Exchange System Efficiency

Low Loop Pumping Power

Efficient Heat Pumps

Well-Designed Ground Loop

© 2007 Kevin Rafferty, PE3/7/2014 GAOI 2014 14

Energy Efficient Heating:Coefficient of Performance

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or building

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How Geo-Exchange Works

Thermal Conductivity

Bore field actsas a battery, storingheating energy in the summerand releasing it in the winter

GeothermalBore Field

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What is a Geo-Exchange Heating and Cooling System?

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KEY:

Ground Coupled heat exchanger

Piping Network

Pumps

Water source heat pumps

Controls

VFD

PD

T

Life Cycle Costs

• Determine the real cost of ownership of an HVAC system– System First Cost– Maintenance– Energy Consumption– Debt Service – Equipment replacement and Frequency

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Building Winnebago Middle SchoolArea 66,000

Thermal Conductivity 1.3Geothermal Budgeting Average Total

$/sq. ft. $Demolition $0.39 $26,004.00One Pipe Loop $2.87 $189,526.42Insulation $0.57 $37,374.16Pumps $0.14 $9,143.79Expansion Tank $0.11 $7,128.76Air Venting $0.02 $1,417.61Equipment Installation $0.78 $51,218.62Electric/Controls $2.15 $141,900.00Sheet Metal $1.28 $84,337.26General Work $1.04 $68,569.47Condensate drainage $0.08 $5,204.80Equipment Mark-up $0.40 $26,620.00

Balance $0.10 $6,600.00Chemical $0.03 $1,819.28Glycol $0.11 $7,118.83

Total $9.98 $637,979.00

Well Field $5.90 $445,566.00Energy recovery Equip $1.65 $108,900.00Equipment $4.25 $266,200.00TOTAL $22.10 $1,458,645.00

2 pipe Estimate

Demolition $0.69 $45,540.00Two Pipe Loop $4.30 $283,800.00Insulation $1.10 $72,600.00Pumps $0.05 $3,300.00Expansion Tank $0.02 $1,320.00Air Venting $0.04 $2,640.00Equipment Installation $1.88 $124,080.00Electric/Controls $2.15 $141,900.00Sheet Metal $1.92 $126,720.00General Work $0.45 $29,700.00Equipment Mark-up $0.98 $64,735.00

Balance $0.17 $5,000.00Chemical $0.03 $1,000.00Glycol $0.11 $0.00

Total $12.98 $856,795.00

Boiler $0.00 $0.00Chiller $1.89 $124,666.67Energy Recovery Equip $1.65 $108,900.00Fan coils $3.00 $198,000.00TOTAL $19.52 $1,288,361.67

Geo Differential $170,283.33% Differential 13.22%ICEF Grant $56,193.50

Net Geothermal Cost $114,089.83

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Maintenance Costs

• From ASHRAE Data– Lowest maintenance cost system

• No boilers or cooling towers to maintain• Refrigeration systems are factory sealed

– Maintenance technician cost• “Residential” type technicians can manage the

maintenance.• No large equipment requiring special tools and

training is involved.

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Maintenance Costs - ASHRAE

Various HVAC Systems Maintenance Costs in 2004 Dollars ($/ft2-yr)

Age of System (Years)

0 2 5 10 20

GSHP (WLHP less Cooling Tower)* 0.208$ 0.215$ 0.226$ 0.243$ 0.277$ WLHP 0.360$ 0.367$ 0.378$ 0.395$ 0.429$ DX-Cooling/Electric Heating 0.382$ 0.388$ 0.399$ 0.416$ 0.450$ 2-Pipe Fan Coil w/ CI Boiler & Recip Chiller 0.523$ 0.530$ 0.541$ 0.558$ 0.592$ VAV w/ Firetube Boiler & Recip Chiller 0.634$ 0.641$ 0.651$ 0.668$ 0.703$ 4-Pipe Fan Coil w/ CI Boiler & Recip Chiller 0.686$ 0.693$ 0.703$ 0.720$ 0.755$

* Cooling Tower Reduction Estimate not in ASHRAE ChapterOriginal work in 1983 dollars, here inflated to 2004 dollars using US Dept of Commerce CPI rate of 1.90ASHRAE 1995 Applications Handbook, Chapter 33, Table 4Based upon analysis by Dohrmann and Alereza (1986)Costs are from office buildings only

Washington Elementary School Belvidere, Illinois

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Client:Belvidere Community Unit

School District 1001201 5th Avenue

Belvidere, IL 61008

815-544-0301Contact: Michael Houselog, Superintendent

Geothermal HVAC System retrofit9,755 m2

60+ classroomsOne Pipe Design

Energy recovery ventilationDigital control system

Lighting retrofit throughout the classroomsVRF (Variable Refrigerant Flow) in office area

Annual operating cost savings -$64,000Renovation over 1 summer

$26.12/ m2

System Life

• Ground Source – Bore Field- 100 yrs– Heat pump- 20 yrs– Piping - 50-100 yrs– Pumps- 20-30 yrs– Digital controls- 15 yrs– Thermostats- 10-15 yrs

• Conventional– Condensing unit- 15 yrs– Boiler- 15-20 yrs– Air handler 20-30 yrs– Piping 50-100 yrs– Pumps 20-30 yrs– Digital controls- 15 yrs– Thermostats- 10-15 yrs

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HVAC System Designer

• Responsible for– Thermodynamics of the

system– Design of system hydronics– Specification of the entire

HVAC system• The ground HX is part of it!

– The entire system performance

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Water Source Heat Pumps(Self-Contained Approach)

• Many consider: Traditional Equipment• Horizontal Units• Vertical Units• Water to Water• Console Units

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Water Source HP’s, Traditionally

– “100’s of noisy boxes” above the ceiling– “Require” cooling towers or boilers “to work right”– 2-pipe controlled water distribution

• Water flow control• Motorized isolation valves • Variable speed drives

– Have maintenance issues• Low flow at the end of the distribution • Low temp difference

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New Paradigm• Many different heat pump systems• When properly designed and implemented, ground loops

can provide all system heat rejection and heat addition• Water distribution

– Traditional 2-pipe variable capacity– Individual circulations– Circulators with central pumps– One pipe

• Lower maintenance costs– Simpler distribution– Managing flow to the units

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Non-Traditional Equipment• Chiller Heaters

– Chilled beams– Fan coils

• Vertical Stack Units• Variable Refrigerant Flow• 100% outdoor air units• Roof top units

– Single Zone– VAV

Why Ground Source for A/Es?

• Delivers client satisfaction through – Simplicity– Performance – Value

• Area where experience and expertise is demonstrated with performance.

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Supplemental Funding• Supporting funding is available from

different areas– Illinois Clean Energy Community Foundation– AMEREN/Com ED– DCEO– Electric Cooperatives– Tax Incentives– Advanced Depreciation

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Questions

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