Dimensioning of de-icing and snow melting systems supplied ... · XVIII EYGEC – Ancona / Italy...

XVIII EYGEC – Ancona / Italy – June 17-20,2007 Session 5.Environmental Geotechnics

Dimensioning of de-icing and snowmelting systems supplied by

geothermal energy

by R. KALLER

Institute for Soil Mechanics and Geotechnical Engineering


Kaller: ”Dimensioning of de-icing and snow melting systems supplied by geothermal energy”

Geothermal Energy

extracting heat from ground > „Geothermal Energy“

in Central Europe: constant earth temperature is in average approximately 10 – 12 °C in a depth of about 10 – 20 meters

utilization of geothermal energy using suitable systems integrated in earth-coupled structures (foundations ...)



Principle of the heat pump

ENERGY FOUNDATION

HEATINGSYSTEM

Temperature of Extraction: 0 – 4°C

Soil Temperature: 10 – 12°C

primary circuit

secondary circuit

Heating Temperature25 – 45°C



Energy consumption

heating with heat pump:

→ saving a large amount of

primary energyHP

1/4 part external energy for operation of heat pump

(electricity or gas)

3/4 partsgeothermal energy 1 part

useableenergy



Recent Development:double use of „Energy Foundations”

Deep foundations such as

piles

diaphragm walls

base slabs

reach to depth with constant earth temperature,

offer large earth coupling elements and therefore

are ideal structures for „Energy Foundations“ such as

„Energy Piles“

„Energy Diaphragm Walls“

„Energy Slabs“



Application for Building Constructionenergy diaphragm wall

energy pileenergy bottom slab





distribution block





distribution block

manifold





distribution block

manifold

heat pump





distribution block

manifold

heat pump

heating / cooling



Utilization of Tunnels

large surfaces are in contact with earth

constant temperature because of depth

internal heat sources (trains, lights, …) increasetemperature

ideal structures for geothermalenergy utilization



Projects – NATM Tunnel

Development of heat absorber systems for NATM

“Energy Membrane”



Methods of plant utilization

Utilizationinside company

For stations,operation centers,

public areas...

Pavementheating

For streets, bridges,railway stations(platforms), …

Third partyutilization

Sell energy to public or

private buildings



• Text des Gliederungspunktes

Pavement heating



Construction details:

pipe system

ground loop heat exchander

heat pump / circulation pump

controller unit



Pavement heating

+ storage

Swiss project “SERSO”



Pavement heating / cooling increases asphalt-lifetime



nT

AQ

AtQqkond v

&&

∂∂

−=== λ

Tqkonv Δ⋅=α&6,3

1⋅⋅= W

WV r

Amq&

&

cWScSgesS qqqq &&&& ++=,

Tq SS Δ⋅=α&

evaporation konvection radiation

ASHRAE: Ar=Af/At



Heizleiterabstand h und mittlere Heiztemperatur tH bei verschiedenen Heizleitern und einer Verlegungstiefe s=15cm

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50

Rohrabstand h [cm]

mitt

lere

Tem

pera

tur d

es R

ohre

s - a

ußen

tH [°

C]

Recknagel: qo = 210 W/m² - tm = 31 °C - d = 7,4 mm

FEM: qo = 210 W/m² - tm = 31 °C - d = 7,4 mm

Recknagel: qo = 210 W/m² - tm = 31 °C - d = 30 mm

FEM: qo = 210 W/m² - tm = 31 °C - d = 30 mm



FEM: qo = 140 W/m² - tm = 15 °C - d = 30 mm



Heizleiterabstand h und mittlere Heiztemperatur tH bei verschiedenen Heizleitern und einer Verlegungstiefe s=35cm

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50

Rohrabstand h [cm]

mitt

lere

Tem

pera

tur d

es R

ohre

s - a

ußen

tH [°

C]



FEM: qo = 210 W/m² - tm = 69 °C - d = 30 mm



FEM: qo = 140 W/m² - tm = 41 °C - d = 30 mm



FEM: qo = 93 W/m² - tm = 22 °C - d = 30 mm

Heizleitertemperatur tH an der Rohrinnenwand abhängig von der Verlegungstiefe s in cm bei unveränderlichem Horizontalabstand der Rohre

h=20cm und verschiedener Energieanforderung qo (155; 225; 338 und 451W/m² jeweils mit to an der Oberfläche von 2°C)

0

10

20

30

40

50

60

70

0 5 10 15 20 25

s [cm]

tH [°

C]

FEM: qo = 451 W/m² - to = 2 °C - h = 20 cm

FEM: qo = 338 W/m² - to = 2 °C - h = 20 cm

FEM: qo = 225 W/m² - to = 2 °C - h = 20 cm

FEM: qo = 155 W/m² - to = 2 °C - h = 20 cm

s

h



Benefits

less car accidents

less traffic jam

less money for winter service

less salt and sand used

less track drilling

nonpolluting and environmental-friendly technique and energy source

reduction of CO2 emissions

supports the compliance with international obligations like Kyoto- and Toronto-aims

savings on investments due to „double use“ of units (energy piles, energy diaphragm walls, energy slabs)

self-regenerating energy source

low dependence on conventional energy

closed circuits which prevent any risk regarding groundwater

positive public image



ReferencesAmerican Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (1999) – 1999 ASHRAE HANDBOOK – HVAC Applicationc (SI cEdition).

Atlanta, USA, ISBN 1-883413-72-9

BRANDL, H. (1998): Energy piles and dia-phragm walls for heat transfer from and into the ground. Proceedings of the 3rd International Semi-nar Deep Foundations on Bored and Auger Piles (van Impe ed.), Ghent; A.A.Balkema, 37-60.

BRANDL, H. (2001): Energy foundations and other thermo-active ground structures. 41st Rankine Lecture, British Geotechnical Association, (pub-lished2006: Vol.56, No.2, pp 81-122)

CHAPMAN, W.P., (1952): Design of snow melt-ing systems. Heating and Ventilating (April):95 and (November):88.

EUGSTER, W.J. (2002): SERSO PLUS – Neue Wege in der Belagsbeheizung. Geothermische Ener-gie 38/39, 10. Jahrgang/Heft 5/6 http://www.geothermie.de/gte/gte38-39/serso_plus_.htm

HILTGARTNER, K., KALLER, R., SVANDA, N. (2007): Vienna as a world class environmental city, the example of CO2 reduction according to the Kyoto Protocol. in: "UPE 7 World class cities: envi-ronmental impacts and planning opportunities", In-ternational Environmental and Planning Association; University of Technology Tampere, Bangkok, Thai-land, 978-974-537-995-4, p 76.

HOPKIRK, R.J., HESS, K., EUGSTER, W.J., KNOBEL, P. (1994): SERSO – Pilotprojekt zur Sonnenenergierückgewinnung aus Straßenoberflä-chen. Hrsg. Bundesamt für Straßenbau und Tiefbau-amt des Kanton Bern http://www.geothermie.de/oberflaechennahe/serso/serso.htm

LIU, X. (2005): Development and experimental validation of simulation of hydronic snow melting systems for bridges. Ph.D. Thesis, Graduate Collage of the Oklahoma State University, Stillwater, OK.

MARKIEWICZ, R., ADAM, D. (2003): Utilisa-tion of Geothermal Energy using Earthcoupled Structures – Theoretical and Experimental Investi-gations, Case Histories. XIIIth European Confer-ence on Soil Mechanics and Geotechnical Engineer-ing. 25-28th August 2003, Prague.

RECKNAGEL, H., SPRENGER, E., SCHRA-MEK, E.-R. (2007): Taschenbuch für Heizung und Klimatechnik Oldenbourg Industrieverlag, München, Hrsg.:SCHRAMEK, E.-R.

WABERSECK, T., (2006): Temperierung von Verkehrsflächen mittels oberflächennaher Geother-mie. 29.Baugrundtagung 2006, Messe und Congress Centrum Bremen, Spezialsitzung „Forum für junge Geotechnik-Ingenieure“



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Dimensioning of de-icing and snow melting systems supplied ... · XVIII EYGEC – Ancona / Italy...

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