Dr. Xinbao Yu, Assistant Professor Dr. Nan Zhang, Postdoc Research Fellow Department of Civil...

USE OF GEOTHERMAL ENERGY FOR DE-ICING APPROACH PAVEMENT SLABS

AND BRIDGE DECKS

Dr. Xinbao Yu, Assistant ProfessorDr. Nan Zhang, Postdoc Research Fellow

Department of Civil Engineering November 4, 2015

Outline

Winter Snow Road Condition

Current Road Deicing Methods

Shallow Geothermal Energy

Geothermal Energy Earth Structures

Geothermal Bridge/Pavement

Deicing

Underground Thermal Energy

Storage

TxDot Work Plan

North Texas hit with record snowfall Fort Worth a ghost town.

http://www.star-telegram.com/news/local/article12483803.html

DFW: 2015 Spring, 6 day closure, 1 fatal crash

Texas: 642 events (00-10) Nation: 7000 lives lost annually

Winter Snow Road Condition

Winter Road Hazards

https://www.google.com.hk/?gws_rd=ssl#safe=strict&q=Winter+Snow+Ro

ad+hazard

Snow removal and application of de-icing salts/sand

Current Road Deicing Methods

Deicing chemicals: Summary of deicing chemicals (Zhang

et al. 2009)

CHALLENGES WITH DEICING CHEMICALS Pot Holes Costs Environmental Contaminations

Alternatives to Salt

Heated pavement/bridge deck (Electricity)

Heated pavement/bridge deck (Geothermal)

Snow melting system 9th street and I64, Louisville, Kentucky

Snow melting on Mar 14, 1978 Snow melting on Mar 14, 1978

Heated pavementHeated bridge deck

Hydronically heated bridge/pavements

Heat transfer

Heat conduction

Heat convection

Thermal radiation

Heat transfer mechanisms in a hydronically-heated bridge deck (Chiasson and Spitler, 2000)

Heating Mechanisms:

Ambient factors:

Wind speed

Solar radiation

Snowfall/rainfall

Air temperature

Shallow Geothermal Energy as Heat Source

Seasonally ground temperature (Sutman and Olgun, 2013)

Seasonally ground temperature:

Mean earth temperature contours across the United States.

Geothermal Pump – Exchange Heat

Geothermal pump:

Heating Mode – Winter Operation

Geothermal Pump

Geothermal pump - Cooling:

Cooling Mode – Summer Operation of GSHP

Cooling Mode –Conventional HVAC

Geothermal Energy Earth Structures

Ground Loops

Horizontal loops

Top: Schematic plot of a GSHP for space heating and cooling

Bottom: Energy piles as host of the absorber pipes (Johnston et al. 2011)

Geothermal Bridge/Pavement De-icing

Oklahoma State University Geothermal Bridge (Spitler 2000)

Conceptual design: • Part 1: Ground loop heat exchanger (GLHE) • Part 2: Hydronically-heated pavement slabs and bridge

decks• Part 3: Heat pump• Part 4: Control system

Conceptual schematic of ground-source bridge deck deicing (Bowers and Olgun 2014)

Design procedures:

(Chiasson and Spitler, 2000)

Establish required heat flux

Estimate the bridge heating

loads

Estimate the energy

available for thermal

recharge in summer

Design GLHE system

including the number,

spacing, diameter and depth

of the boreholes



Experimental study: Experimental study: Wadivkar Ojas , 1997

“Thermal performance of a bridge deck de-icing system”

The experimental bridge deck section (Ojas, 1997)

The heat pump (Ojas, 1997)


Experimental study: Balbay and Esen, 2010

“Investigation of using ground source heat pump system for snow melting on pavements and bridge decks”

The photographs of initial and intermediate snow melting process on slabs: (a) initial state (t=0) for BS and PS, (b) intermediate state (t=30 min) for BS and PS. (Balbay and Esen, 2010)


Images of bridge surface condition taken by a digital camera along with estimates of snow free area ratio. The last image shows drifted snow on the heated surface after snowfall (Liu and Rees, 2007)

Experimental study: Liu and Rees, 2007

“Experimental validation of modeling snow melting on heated pavement surfaces”

Comparison of measured and predicted bridge average surface temperature (Liu and Rees, 2007)


Experimental study: Chen et al, 2011

“Study of ice and snow melting process on conductive asphalt solar collector”

Images of surface condition during the snow melting process (Chen et al, 2011)

The schematic of pipes and measuring point in tested slab


Numerical simulation (FEM):

Balbay and Esen, 2013

“Temperature distributions in pavement and bridge slabs heated by using vertical ground-source heat pump systems”

The meshed model of the PS and BS

Typical temperature distribution of PS

Dimensions of the bridge and pavement models


Geothermal bridge heating system (a) 3D bridge schematic, and (b) deep foundation (Xiao et al. 2013)

Finite element mesh for half of the bridge cross section for the Jamestown-Verrazzano Bridge (Xiao et al. 2013)


Xiao et al, 2013

“Use of geothermal deep foundations for bridge deicing”

Measured temperature within the bridge slab compared to the analytical results (Xiao et al. 2013)

Start heating


Temperature distribution (°C) over time with 25 mm O.D. PEX pipe (Becker et al. 2014)

Pavement section profile view (Becker et al. 2014)


Becker et al, 2014

“Finite element modeling of heat transfer in a reinforced concrete pavement”

Time required to reach non-freezing temperature at pavement surface (Beck et al. 2014)


Bridge deck slab used in the analyses and layout of the circulation tube (Bowers and Olgun, 2014)

Temperatures along the vertical section in between circulation tubes (Bowers and Olgun, 2014)

Numerical simulation (FEM): Bowers and Olgun, 2014

“Ground-source bridge deck deicing systems using energy foundations”


Case study: SERSO: Bridge heating in Switzerland

Swiss solar storage system (Eugster 2007) The SERSO system in operation (Eugster 2007)

Heated area: over 1300 m2

Typical average heat output: 100 W/m2

Installation cost: 2500 Euro/m2

Operation cost: 4 Euro/m2 for electricity and maintenance


Case study: Sidewalk heating in Aomori City in Japan

The schematic plain view of the site Sidewalk heating in operation

Designed heat output: 170 W/m2

Annual operation time: 500 hrsInitial installation cost: not knownOperation cost: 6 Euro/m2/year for electricity


Case study: Germany: Bad Waldsee Street

Infrared picture the asphalt street at Bad Waldsee, Germany (Zorn et al. 2015)

Demonstration of successful operation of the system at Bad Waldsee, GermanyHeated area: over 165 m2


Case study: Texas (FHWA-RD-99-158)

Close-up of supply and return manifolds (pipes in center) and thermocouple conduits terminating in enclosure at right.

Heating hoses in place ready for concrete pour; hoses are on 152 mm (6-in.) centers placed 76 mm (3 in) under top of slab, affixed below #4 rebarsInitial installation cost: $1,200,000

Operating cost: $7500


Case study: Laramie, Wyoming

Earth heat system at Laramie, WY (Richard G. Griffin, 1982)


Case study: Five-span pedestrian viaductNebraska (FHWA-RD-99-158)

Flexible expansion loops in supply/return pipes underneath walkway

Deck condition after heating 31h

Design cost: $150,000 Construction cost: $161/m2

Operating cost: $9.25/hr


Case study: Two-lane bridge across Buffalo River, Amherst

County, Virginia (FHWA-RD-99-158)

Riser deliver heated working fluid to a series of evaporators, each serving 10 Perkins tubes in bridge deck

Bridge over Buffalo River on Rt. 60 is on a gentle curve

Design/construction cost: $181,500 ($35/ft2, $10.75/m2)Operating cost: $2160/yr

Case study: Snow melt projects in

Klamath falls Oregon, Boyd, 2003


Bridge decking loops attached to the reinforcing steel

The approach road loops placed latitudinally

Detail of the snow melt system for the stairs


Summary of case study in U.S. (Minsk, 1999)

Underground Thermal Energy Storage

Introduction and background:

Energy foundations

Soil borehole thermal energy storage (SBTES)

Case history performance

http://decarboni.se/ http://ceae.colorado.edu


Type of UTES system: Open system

Closed system

ATES

Aquifer thermal energy storage

BTES

Borehole thermal energy storage

CTES

Cavern thermal energy storageOutline of the most common UTES system (Nordell et al. 2007)


ATES:

Aquifer Thermal Energy Storage

Heat storage medium

Ground water

Minerals in aquifer

Short and long term

Large scale

Problem

Conflicts in ground water use Schematic of ATES system (Nordell, 2000)


BTES:

Borehole Thermal Energy

Storage

Heat storage medium

Bedrock

Soils

Short and long term

Small and Large scale

Suitable for base loading and

unloading for seasonal

thermal energy storage

Section of a group borehole system (Nordell, 2000)

CTES:

Rock Cavern Thermal Energy

Storage

Heat storage medium

Hot water

Long term

Large scale

Problem

Construction is very costly


CTES-Rock Cavern hot water storage (Nordell 2000)


Heat storage materials: Sensible heat storage (by raising the

temperature)

Latent heat storage (by phase change )

Comparison of various heat storage media (stored energy =106 kJ=300 kWh; ΔT=15 K) (Hasnain, 1998)

Case study: Solar BTES in Canada


Computer generated image showing the solar BTES sub-division (Wong et al. 2006)

Boiler Energy Supply for the First 5 Years (Wong et al. 2006)

Benefits: An estimated 5 ton reduction in greenhouse gas (GHG) emissions per home per year will be realized due to the solar BTES operation and related energy efficiency features.

Case study: ATES in Germany

Two ATES systems at

different levels

Upper for cold storage

Lower for heat

storage


Schematic of Berlin Reichstagsgebaude ATES system (not to scale) (Sanner 2001)

Total energy

demand: Power: 8,600 kW

Heat: 12,500 kW

Cold: 6,200 kW

Case study: CTES in Japan

Snow storage at the New Chitose Airport in

Sapporo


The snow storage (L: 200 m, W: 100 m, D: 2 m) is filled up and covered with thermal insulation at the New Chitose Airport in Japan

Comments: This system which is inspired by the Sundsvall snow storage was made for 120.000 to 240,000 m3 of snow corresponding to 5 to 10 GWh of cold


Case study: UTES in Sweden

The principle of ATES (Andersson et al. 2013)

The principle of BTES (Andersson et al. 2013)Ranges of efficiency, energy saving, specific investment and payback time of UTES

applications in Sweden.


Efficiency and cost analysis: BTES

Life cycle cost (LCC) of 20 year period per kWh of recovered energy from the storage area (Gaine and Duffy, 2010)

Summary: Deep system has the highest LCC for small system due to higher losses; medium system has the lowest cost LCC in all the cases.

Task 1: Conduct comprehensive synthesis on the use of geothermal technologies for bridge and pavement deicing

Task 2: Synthesize literature on underground thermal energy storage (UTES) for bridge deck and pavement deicing

Task 3: Feasibility using finite element simulations and cost benefit analysis

TxDot Work Plan

Thermo-Time Domain Reflectometry Probe

Thermo-Time Domain Reflectometry (TDR) probe:

Soil thermal properties

Soil moisture content

Soil density

Photo of thermo-TDR probe Schematic of thermo-TDR probe system (unit: mm)

Comparison between thermo-TDR probe and KD2 probe

Thermal Imager

IR FlexCam Thermal Imager:

Articulating thermal imaging camera with infrared and visible light images fused together

Resolution: 320×240

Sensitivity: <0.05°C

Temperature range:

-20°C - 600°C

Accuracy: ±2°C or 2%

Photo of IR FlexCam Thermal Imager Ti55

http://en-us.fluke.com/products/infrared-cameras/fluke-ti50ft-infrared-camera.html

Dr. Xinbao Yu, Assistant Professor Dr. Nan Zhang, Postdoc Research Fellow Department of Civil...

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