Ohio State’s High-Rise Residence Hall Renovations with
Geothermal Well FieldTom Reeves, Director
Jeffrey Roe, Senior Energy Engineer
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Business Reasons:Quarters to Semester Switch
-Late September through mid-June-Now: Mid August move-in (HOT!)
Additional capacity needed
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This project added ~250 new beds and renovated the spaces for ~2150 existing beds.These residence halls now have air conditioning, new restrooms, new lobby spaces and courtyard
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“South High-Rise” (SHR for short)These are 5 individual 11 story buildings built in the 1950s – heating only without outside air. Rooms designed for doubles and triples with corridor bathrooms
Typical old floor plan:
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Major renovation included:1. Insulation – Walls ~R3 to ~R182. Air Conditioning – Using “Valence” units. 3. Upgraded windows - operable aluminum frame4. Privatized Bathrooms 5. Additional Programming Space
(Study Rooms, Lounges, Courtyard)
Typical new floor plan:
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Move in Day 2013This is the second year for Park-Stradley (pictured)
This is the first year for Smith-Steeb and Siebert
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Design Decisions - GeothermalPros of Geothermal System:1. Expected long lifespan of energy savings2. Upfront costs relatively low due economic conditions at
the time3. GREAT PR
Cons:4. Requires fencing off significant green space for several
years for construction
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Geothermal Well Field Design• 411 wells at 550 feet deep• 4 underground “vaults” for isolating branches of wells
• (7-13 wells/branch)
• Plastic piping used, tracing wires
• Designed for 1500 tons of cooling, expecting more for heating.
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Design Decisions - Fan-Coils vs. ValancePros of Valance Units:1. No fan – no electrical use (other than valve)2. No filter3. No floor space loss4. No refrigerant near student quarters
Cons:5. Takes up ceiling space6. May require higher water temperatures to provide
circulation to heat the room – 150F recommended by our design engineer
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Design Decisions - Large Heat PumpsReasoning:1. We used this system on a much smaller installation, the
510 person dorm “Residence on 10th, which received LEED Gold.
2. Residence on 10th has been operating satisfactorily• The output of the chillers is only 130F here, where fan coils
are used, which allowed for different choices in heat pump selection
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Design Decisions - Large Heat PumpsRequirements:1. Large equipment allows for refrigerant risk mitigation –
minimal HVAC refrigerant lines near student areas2. Condenser side must be able to produce 150F water for
best operation of the valance1. This requirement drove the decision to between two pieces of
equipment1. York CYK 2. Multistack Packaged Scroll
3. Steam remains as backup system
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York CYKPro•Small footprint
Con•Limited turndown, especially heating mode
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MultistackPro•Better turndown / part loading
Con•Large footprint (many units needed)
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York CYKChosen for smaller footprint
Constant 42F/150F or floating either point
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WindowsTriple Glazed, Low E
South and WestSHGC: 0.24U-Value: 0.12 = R-Value of 8
North and EastSHGC: 0.35U-Value: 0.12 = R-Value of 8
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½ slide picture
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Design Decisions - Other Considerations• 2-Pipe risers – Only heating or cooling provided
• Did not include bypass at end of each loop – dead ends, but valance units flush this water within a few minutes.
• Lack of simultaneous heating and cooling uses far less energy• Outside air to hallways and out bathrooms
• No direct outside air to student rooms – requires operable windows.
• Window sash sensors not installed – no ability to cut cooling/heating out with windows open.
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2012-2013 School Year ResultsPark-Stradley was lived in. Plant provided heating and cooling to Smith-Steeb and Siebert as well, as they were under renovation.1. Plant Steam (York CYK not running until spring): 13,700
x 10^6 BTU2. Plant kWh: 1.5M kWh3. Park-Stradley kWh: 1.7M kWh4. Smith-Steeb and Siebert kWh (under construction):
1.0M kWh
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7/30 8/4 8/9 8/14 8/19 8/24 8/29 9/3 9/80
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Complex's Ton-Hrs from Plant and Outside Temperature
Ton-
Hrs
Degr
ees F
2400 Students No Students
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Example Operating Points – 11:30 9/4/13• Commissioning is NOT complete yet• Student Capacity Cooled: 2400 students• OAT: 71F• Chiller EEFT/ELFT/Flow 49.6/43.3/1370 (360 tons)• Chiller kW / kW/ton 788kW / 2.2 kW/ton
• Secondary Chilled Water • SCWS / SCWR / Flow: 46/50/2060 (backflow in bypass
sends warmer water to valances, which work fine at higher temperatures)
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Future Plans• We have (3) 800 ton heat-pump chillers and the existing
load appears to max at out about 550 tons for cooling. • Heating load is unknown, but it appears to also be much
below the available (3) 13.3M Btu/Hr units. • We have added piping to send heat to existing heating
hot water only low rise buildings nearby – ready for this winter
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Lessons LearnedKeep mechanical rooms above sewer level
Water main burst, flooding the chiller bunker. Much equipment needed rebuilt/replaced.
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