Underfloor Air Distribution and Radiant Heating/Cooling · Underfloor Air Distribution and Radiant...
Transcript of Underfloor Air Distribution and Radiant Heating/Cooling · Underfloor Air Distribution and Radiant...
Underfloor Air Distribution and Radiant Heating/Cooling: Innovative Applications of Geothermal HP Systems in Schools
STEPHEN HAMSTRA, P.E., HBDP, LEED AP, CGD
IGSHPA Technical ConferenceGrapevine, TexasOctober 22, 2009
Why?
Reduce operational costs – free up $$$ for education
Community Credibility – show good stewardship
Attract students/families and retain staff
Funding opportunities – donors like “green” projects
Case Study: Existing Elementary School•Retrofit Geothermal Heat Pump Project
•Replacing Existing Gas Boiler/Classroom Unit Ventilators
•Ventilation Energy Recovery built into Unit Ventilators
•Adding cooling
Jamestown Elementary Site Plan
Floor Plan
New Exterior Elevations
Mechanical Floor Plan
Heat Pump Unit
Unit Ventilator Replacement
Lessons Learned:•Geothermal Heat Pump Unit acoustics are important!
•Connections to outside air louvers – special attention to sealing
Jamestown Elementary
The “Flux Capacitor” Concept
What does time travel have to do with Geothermal Heat Pump Systems?
GeoExchange Systems can “store” massive amounts of energy (like a “flux capacitor”) giving us a thermal flywheel effect
GeoExchange Systems can “time shift” that energy
Heat Dissipation/Absorption
GeoExchange Heat Transfer
Solar Radiation
Conduction/Convection/Radiation at surface
Conduction to surrounding soil
Ground Water Movement
1 Gigawatt-hour = 3.4 Billion BTU-hours
Typical 1,000 ton capacity system:
150,000 borefeet at 20 feet on center
Control volume of 60 million cubic feet of soil
At 100 #/CF density => 6 billion pounds
At 0.35 BTU/ degree F Specific Heat we get:
2.1 Billion BTU’s stored per one degree F
To store 1.21 Gigawatt-hours we need only change the soil temperature by 1.6 F!
If the annual temperature swing for this system was 30 F, we would be “storing” more than 22 “gigawatts!”
Heat Dissipation/Absorption
Combining Mixed Use Buildings on Common Loop
THE ENERGY CHASSIS CONCEPT Pioneered by GMB A+E
Geo HX In
Geo HX Out
Geo HX In
Geo HX Out
CHWR In
CHWS OutHWS Out
HWR In
VVP VVP
Extended Range Heat Pump Chiller
Operating Modes:
1. Heat recovery - make chilled water and hot water simultaneously
2. Chilled water – make chilled water and reject heat to geothermal HX
3. Hot water – make hot water and absorb heat from the geothermal HX
THE ENERGY CHASSIS CONCEPT Pioneered by GMB A+E
Case Study: New Elementary School•Central Plant Geothermal Energy Center
•Displacement Ventilation System – 100% Outside Air/No Recirculation
•Radiant ceiling cooling
•Radiant floor heating
•Net annual energy consumption 50 kBTU/SF/year
Georgetown Elementary School Site Plan
TOTAL SQUARE FOOTAGE
Footprint : 66,765
Mezzanine: 2,071
Total: 68,846
Floor Plan
Radiant Cooling Panel
Concept Diagram for Ventilation
Mechanical Floor & Site Plan
Geothermal System Floor Schematic
To effectively apply advanced concepts we need to have advanced simulation tools for design.
SIMULATIONS ARE IMPORTANT
Radiant Cooling Panels and Displacement Diffusers
Sp1
65.2
76.2 °F
70
75
FLIR Systems
Sp1
65.7
76.6 °F
70
75
FLIR Systems
Thermal Images
Radiant Cooling Panels
Radiant Floor Heating
Lessons Learned:•Control deadbands are important – Clients can be hard to control…
Georgetown Elementary
Case Study: New Elementary School•Central Plant Geothermal Energy Center
•Displacement Ventilation System – 100% Outside Air/No Recirculation
•Underfloor (raised floor) Air Distribution System
•Thermal mass energy storage
•Net annual energy consumption 35 kBTU/SF/year
Quincy Elementary
Typical Classroom
Cafetorium
Media Center
Raised Access Floor - Diffusers
Raised Access Floor – Floor Power/Data Outlet
Geothermal Borefield- Loop Manifolds
Central Plant Geothermal Heat Pumps
Lessons Learned:•Give yourself some room with regards to capacity and performance at high condenser water temperatures – don’t live life on the edge!
•Thermal mass can work with you or against you – think about it when developing control sequences.
Quincy Elementary
Conceptual Net Zero Energy School
Can we create Net Zero Schools?
• Optimized Building Envelope
• Daylight Harvesting Systems
• Advanced Lighting Controls
• Earthtubes
• Solar-Reactivated Cooling
• Radiant Chilled Ceilings/Chilled Beams
• Radiant Floor Heating
• Displacement Ventilation
• Hybrid Geothermal Heat Pump System
• Solar Domestic Hot Water Heating
• Ventilation Energy Recovery Systems
• Potable Water Use Reduced by 90% through Rain Water Harvesting and Low Flow Fixtures
• Solar Photovoltaic (PV) System for Electrical Generation
• Wind Turbines for Electrical Generation
Yes it can be done! And not just schools…
Whole Building Design
Whole Neighborhood/Campus Design
Whole Community Design
Design Philosophy (everything connects to everything…)
Classical engineering training says “solve problems one at a time”.
Design Philosophy
We say “NO!”
This is partly how we got into the challenging position we are in today – we’ve solved
problems without first considering the solution in a larger context.
Consider:
(in order of importance)
1. Reduce the loads, reduce the loads, reduce the loads…
2. Recover wasted energy wherever you can
3. Find ways to reuse waste energy
4. Consider innovative energy systems (geothermal heat pumps)
5. Consider renewable energy systems
6. Measure, verify, learn, improve, repeat…
Design Philosophy
THANK YOU!
www.gmb.com
STEPHEN HAMSTRA, P.E., HBDP, LEED AP, CGD
Executive Vice President