Geothermal Heating & Cooling

Digging Deeper for Energy Savings

Luann T. Kolstad

Business Manager

Prospect Heights School District 23

Geothermal Ground-source heat pump

GeoExchange

Geo-exchange

Geothermal heat pump

Earth-coupled heat pump

Geo

Earth Energy

Why Geothermal in Schools?

• Saving energy and dollars… typically 50% lower energy bills. Geothermal provides heat AND cooling – one system.

• Saving on maintenance.• Comfort/health in the classroom.• Be green on the environment.

Enhanced Learning Environment

• Noise• Temperature control and adjustability• Humidity control• Allergen control• Ventilation• Efficiency• Adaptable to changing education

environment

Why Not Geothermal in Schools?

• Higher initial cost.• Age of current HVAC System• Technology can be more complicated than

traditional HVAC.• Limited space - need for earth-loop.

A simple explanation of geothermal technology

The mystery of Geothermal heating and cooling

The more complicated explanation.

Geothermal 101

The simple view of what geothermal does …

Uses the earth’s free energy for heating in the winter and cooling in the summer

Geothermal 101

How does it work? A more detailed view.

Common Geothermal SystemThe traditional closed loop outside system … with a two-pipe installation and conventional geo equipment … either a series of smaller “residential sized” heat pumps, or larger “commercial sized” heat pumps.

(Loops could be installed vertically in boreholes up to 500 feet deep – or horizontally in a trenched configuration, approximately 6 feet deep or more.)

Another version – common in schools – the one-pipe systemIn this version, the loop field is connected to the individual geothermal units inside the facility, with a single, large geothermal pipe and all the individual units draw from that that pipe.

Advantages are lower initial cost and efficiencies from different zones (rooms) within the school that might require heating and cooling at the same time. This system works as one to move that energy throughout the facility.

(Kirk Mescher of CM Engineering in Columbia, MO.)

This is what construction looks like…

Geothermal Drilling

• Piping: Piping installed in bore holes is a closed loop system. Piping material is a high density polyethylene material designed for geo applications. Material carries 50 year warranty. Think yellow natural gas pipe.

• Solution flowing through pipes: 80-85% water, 15-20% food grade propylene glycol

• Project overseen by IGSHPA (International Ground Source Heat Pump Association), NGWA (National Ground Water Association) and IDPH (Illinois Department of Public Health).

Loop field construction

Loop field construction

Loops under athletic field

Loop installation

MacArthur Drilling

MacArthur Middle School

MacArthur Main Loop

Branch Off Main Loop

New Bard Unit in Classroom

Prospect Heights SD 23

• Elementary School District:– Serving 1500 students– Two Campuses– Five Buildings:

• 1 Middle School (Main Campus) 6th – 8th Grades• 1 Grade School (Second Campus) Pre-K – 1st Grades• 1 Grade School (Main Campus) 2nd – 3rd Grades• 1 Grade School (Main Campus)4th – 5th Grades• 1 Administration Building (Main Campus)

In the Beginning…..

• District faced with Deferred Replacement of Mechanicals in all Buildings:– Obsolete Unit Ventilators and Controls– Boilers at end-of-life and beyond– AHU at end-of-life and beyond– Existing HVAC Systems in locations where A/C

was all reaching end-of-life– 3 Schools – No Air Conditioning except offices.

At a Cost of…..

• $5,145,875 - Replacement of only Priority Mechanical Items.

• Priority Maintenance Items Account for only ½ of Necessary Mechanical Replacements!

• Cost does not include adding air conditioning.• $3,629,000 – Estimate from 2008 to add air

conditioning to three buildings. • $8,774,875 – Total for both.

The Answer…..

• $6,203,064 Estimated Total Cost before architectural fees of Geothermal Heating & Cooling in Four Schools.

• Project will result in replacement of ALL mechanical systems in four schools.

• Minimal maintenance for at least 20 years!• Domestic Hot Water Heaters are only use

of Natural Gas = Decreased Gas Bill!

Here we Go!

• Summer 2013: – MacArthur Middle School Converted to

Geothermal Heating & Cooling– Two Well Fields Drilled:

• Central Campus field 120 bore holes at a depth of 500 feet. Sized to serve middle school, two grade schools and administration building.

• Eisenhower Campus 32 bore holes at a depth of 500 feet.

• **We call it “Bore Holes” instead of “Wells”**

First Winter Results

In Graphic Form

February 2014 Usage Comparison

MacArthur Middle School : 110,000 sq ft 352 ThermsMy Humble Home: 2,900 sq ft 254 Therms

Some key geothermal thoughts

• If an engineer tells you “geothermal doesn’t work in…” walk away … Fast.

• Also walk away from the engineer/expert who makes the blanket statement that “geothermal is too expensive.”

Key thoughts, cont.

• Geothermal can work in new school construction or can be used to retrofit a school HVAC system.

• Geo provides BOTH heating and cooling.• While a simple concept, geothermal can

be designed in various configurations.

Key thoughts, cont.

• Geothermal ISN’T always the best option.• PARTNER WITH COMPETENT,

EXPERIENCED PROFESSIONALS!!!!!• The design element is KEY!• Using the low bidder – sometimes you get

what you ask for.

Incentives for geo installation

• Illinois Clean Energy Community Foundation.

• Department of Commerce and Economic Opportunity (DCEO)

www.gaoi.org