System description

Heating in winterCooling in summer

GeoCollect-geothermal absorber system

GeoCollect®

High-level geothermal energy

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General information on the GeoCollect system

1. Die physikalischen Grundlagen 03

2. Die Technik des Absorbers 06

3. Die Dimensionierung (Auslegung) des GeoCollect-Systems 07

4. Hinweise und Ideen zur kostengünstigen Montage 09

5. Arbeitsschritte bei der Verlegung 10

6. MöglichkeitenzurEffizienzsteigerung 16

7. Kombination mit anderen Energiequellen 17

8. ÜberbauungmitversickerungsfähigemPflaster 18

9. ErfüllenvonAuflageninTrinkwasserschutzgebietenZone3a/b 19

Contents

Table of contents

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Please observe regulations according to DIN 4124 (10.02)!

GeoCollect-absorber modules collect valuable energy from the soil surrounding them. Correct dimensioning ensures reliable regeneration of the soil in the absorption area.

GeoCollect-absorber modules are an effective and affordable alternative to soil sensors. This system requires much less space than conventional collectors.

1. The physical principles

The physical principles

0,7 mVerlegeabstand

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Function – extraction rate

Theoptimumsurfaceareaprincipleandthethin-layer&turbulentflowthrough(low-flowprinciple)allow theGeoCollect-absorbers toachieve theirefficientextractionrate.

The vertically installed GeoCollect-absorbers take the energy from a large cubatureofsoil(approx.0.5mhorizontalandapprox.0.4mvertical).Thislayout,withadistanceof0.7mbetween theabsorbers, leads toextremely lowspatialrequirementswithanextraction rateof142.61W/m2.Thisapplies tomore than 95 % of all climate zones and soil types in Germany.

Theperformance table, in theAttachments to theTechnicalmanual, is requiredforprecisedesignwithregardtobothpossibleextractionperformanceaswellasannual output.

In the case of dry gravel soils, additional water retention measures are to beplanned(e.g.rainwaterirrigation,sheetingbasin).

The performance values are determined based on the average soil composition in Germany:

The physical principles

>=135

126 - 134

117 - 125

108 - 116

99 - 107

90 - 98

82 - 89

75 - 81

64 - 74

55 - 63

< 55

m 0

- 20

- 40

- 60

- 80

- 100

Mittlere GeothermischeErgiebigkeit[kWh / (ma)]*

141

130

121

118

*) berechnet für 1800 Betriebsstunden

GWL Grundwasserleitung

GWGL Grundwassergeringleiter

1. The physical principles

0-5 m sand, gravel (quaternary) 25 - 30 m sand. gravel (quaternary)

Mean geothermal yield[kWh / (ma)]*

*) calculated for 1.800 operating hoursGWL aquifers GWGL aquitards

20 - 40 m fine sand, clayey, silty (tertiary)

20 - 30 m alternating clay/sand, with lignite (tertiary)

15 - 25 m fine sand, clayey, silty (tertiary)

Extraction range of GeoCollect modules: 1.10 to 1.6 m depth

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Period Jan. / Feb.

Temperatureprior to operation of heat pump

Temperature after halfan houroperation ofheat pump

Temperature after one hour

operation ofheat pump

Temperature after one hourpause ofheat pump

Temperature after two hours

pause ofheat pum

WQA(Outlet from heat pump)

3 °C - 2 °C - 4 °C 1,9°C 2,5°C

WQE(Inlet into heat

pump)3 °C 1 °C - 1 °C 2,1°C 2,6°C

Thisexampleshowshowtheenergystoredinthesoilrepeatedlyleadstoavaluableenergy phase change at the outside of the absorber with the result that the system attheJan./Feb,levelvirtuallycompletelyregeneratesintheheatpumpswitchoffphase even after a long winter (e.g. until April).

Typical temperature progression at the start and peak of the heating period

Period Sept. / Oct.

Temperatureprior to operation of heat pump

Temperature after halfan houroperation ofheat pump

Temperature after one hour

operation ofheat pump

Temperature after one hourpause ofheat pump

Temperature after two hours

pause ofheat pum

WQA(Outlet from heat pump)

12 °C 8 °C 7 °C 10 °C 11 °C

WQE(Inlet into heat

pump)12 °C 11 °C 10 °C 10 °C 11 °C

The physical principles

1. The physical principles

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2. Absorber technology

Performance Pressure loss

Leistung PPer module

Delta pPer module

Delta p per group(10 modules)

99,83W 96 Pa 960 Pa

Geometry

Areaextractionrate(plot area)

Length Width Absorption area

142,61W/m²(two absorbers per 1.4 m2)

0,89m 0,35m 2x0,31m²

width 990 mm

Hig

ht 3

50 m

m

GeoCollect®

7Dimensioning (design) of the GeoCollect system

3. Dimensioning (design) of the GeoCollect system

Design with reference to the heat extraction performance from the soil and cooling performance to be covered or the brine/water heat pump used.

• Trenchdimensionswithuprightinstallation(DxW): 1.5mx0.7m• Trenchlength(for10absorbers;5eachinsupplyandreturn): 5m• Ideallyadditional: +0.5monconnectionside

• The theoreticallymissing 0.17Wper absorber = 1.7Wper group is effected bytheexistingroutinginthesoilnottakenintoaccountinthedesign.1

1Theperformancespecificationsarebasedonthespreadingsupply/return brineof3Kat5l/mingroupflowrate.

Extraction rate B0/W35° -> 3 kW 4 kW 5 kW 6 kW 7 kW 8 kW 9 kW 10 kW 11 kW 12 kW 13 kW 14 kW 15 kW

Calculated module amount [99.83Wmodule]

30 40 50 60 70 80 90 100 110 120 130 140 150

Number of circuits [10modulespercircuit]

3 4 5 6 7 8 9 10 11 12 13 14 15

Length of individual trench [m]

5 5 5 5 5 5 5 5 5 5 5 5 5

Number of trenches of 5 m length,0.7mwide,1.5mdeep

3 4 5 6 7 8 9 10 11 12 13 14 15

Plot area required [m2]

21 28 35 42 49 56 63 70 77 84 91 98 105

Groupflowthrough [l/min]

5 5 5 5 5 5 5 5 5 5 5 5 5

Totalflow [l/h]

900 1.200 1.500 1.800 2.100 2.400 2.700 3.000 3.300 3.600 3.900 4.200 4.500

Fillamountabsorber[excl.WP+distributor][litre]

60 80 100 120 140 160 180 200 220 240 260 280 300

Proportion of antifreeze 29%ethyleneglycol][litre]

17,4 23,2 29,0 34,8 40,6 46,4 52,2 58 63,8 69,6 75,4 81,2 87,0

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Area required for a GeoCollect system: approx. 1/3 of the effective area of the building*

Blue: area required for conventional near-surface geothermal systemsRed: area required for GeoCollect absorber system

* The GeoCollect-system often requires only 1/3 of the effective area of the building.The area required can be reduced to approx. 1/6 of the effective area of the building with installation at two levels (lower level 2.5 m installation depth).

Space comparison

Dimensioning (design) of the GeoCollect system

3. Dimensioning (design) of the GeoCollect system

GeoCollect®

9Informationandideasforinexpensiveinstallation

4. Information and ideas for inexpensiveinstallation

Figure

Fig.1 Fig.2

Fig.3 Fig.4

> Fig.1:Excavation trenches parallel to house walls: trenches running parallel to the house walls are used. Thus only a small surface area is dug up.

> Fig.2:Available trenches:existingtrenchesandsupplylinesaround thehouse(e.g.wastewater,electricityorcable)canbeused. Wastewaterheatisabsorbedviageothermalexchangers.

> Fig.3:Embankments: small trenches to take geothermal absorbers can be dug in embankments such as patios or natural slopes.

> Fig.4:Parking area: parking areas with permeable paving can be used double by installing underground absorber modules.

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5. Workstepsfor installation

Workstepsforinstallation

1.Excavationof0.8mtrenchwidth(installationdistance70cm)and1.5mdepth

…orcompleteexcavation.

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2. Pre-assembly of the GeoCollect absorber groups of 10 modules according to the installation plan

5. Workstepsfor installation

Workstepsforinstallation

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8. Arbeitsschritte bei der Verlegung GeoCollect

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4. Attachment of the manifold in the light well (rigid foam sheet as insulation to building wall); then fusing of the supply and return lines of the group to the PP sockets at the brine manifold and adjustment of the volume flowsoftheindividualgroups;thecollectorpipesaremadeofPE.Furtherroutingintothehouseservicesroom is effected with PE fusion sleeves

3.InstallationoftheGeoCollectgroupsinthetrenchesorexcavatedholeaccordingtotheinstallationplan.The illustration shows a bentonite barrier layer as an additional measure in drinking water protection areas.

5. Workstepsfor installation

Workstepsforinstallation

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6.FillingandpurgingoftheGeoCollectsystem5. Pressure test air 1 h at 6 bar

... initially completely; then group by group until rinsing is bubble-free.

7. Pressure test brine 12 h at 3 bar

5. Workstepsfor installation

Workstepsforinstallation

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GeoCollect®

8.Fillingthetrenchesorcompletelyexcavatedholewithcohesivesoilorslurrysandto10cmcoveringtheabsorbers;thenbackfillingwithpermeablespoil.

5. Workstepsfor installation

Workstepsforinstallation

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9. Slurrying of GeoCollect system to covering of the GeoCollect absorbers

10.Positioningofwarningtapesapprox.0.5mbelow ground level

11.Backfillingoftrenchesandcompaction.

5. Workstepsfor installation

Workstepsforinstallation

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GeoCollect®6. Possibilities of

increasingefficiency

Rainwater irrigation over the absorber groups (imperative for dry gravel soils)

WasteheatutilisationfromwastewaterpipingAn average detached house emits energy into the environment via the waste water system every day. A large part of this energy can be recovered by positioning the absorber modules on either side of the waste water piping (distance 30 cm).

Possibilitiesofincreasingefficiency

Rainwater tank

GeoCollect®

17Arbeitsschritte bei der VerlegungCombination with other sources of energy

7. Combination with other sources of energy

The GeoCollect-absorber system is an ideal addition to other sources of energy for brine/waterheatpumps.

The GeoCollect-system can be designed correspondingly smaller, thus savingcostsandreducingspatialrequirements,dependingontheoutputanddurationofavailability of other sources of energy.

Typical combinations are:

• Supplementtosolarthermalsystemsandenergyroofs,theoutputofwhich canbeusedinwinterasthesourcefortheheatpump(Fig.1+2)• Wasteheatutilisation(e.g.compressorwasteheat;otherprocesswasteheat) or“cellardehumidification”inoldbuildingsbyusingheatexchangers• Wasteheatutilisationfromphotovoltaicsystemsorback-ventilatedfacades• SLabsorbers(noiselessair/heatexchangerse.g.asheatcollectorfences) which use the air as a source of energy at plus temperatures and the soil only at low air temperatures.

Fig.1 Fig.2

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8. Building over with permeable paving

Building over with permeable paving

versickerungsfähiges Pflaster(Versickerungswert: 270 l/s ha)

offenporiger Beton(Kf-Wert > 10-4 m/s)

Kies

Steinfreies Verfüllmaterial(Aushub/Schlemmsand)

0,1 - 0,2 m

0,1 - 0,5 m*

0,1 - 0,6 m*

0,7 m

Distribution systems according to Tichelmann are connected in larger GeoCollect systems. Building over can be effected with permeable paving with drain concrete underneath (according to the required bearing load).

Permeable paving (seepage: 270 l/s ha)

Open-Pored Concrete (Kf value > 10-4 m/s)

Gravel

Stone-free backfill material (spoil/slurry sand)

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GeoCollect®

GeoCollect®

Conformingwithrequirementsindrinkingwaterprotectionzone3a/b

9. Conforming with requirements in drinking waterprotectionzone3a/b

The GeoCollect-system often makes it possible to set up a geothermal system even if a borehole cannot be permitted.There are not usually any particular requirements if the aquifer layers have a high distance to the GeoCollect-system in drinking water protection zone 3a/b. Atlowerdistances,e.g.abentonitebarrierlayercanprovidethenecessarysafety.Agroundwater detection rod can be set up to demonstrate the leakproofness of the bentonite barrier layer.Wewouldbepleasedtoassistyouintheplanningindirectdiscussionswiththerelevant authorities.

Installation with bentonite barrier layer

Perforated KG pipe as holder for the groundwater detection rod

Basic structure (cross-section) with bentonite barrier layer

5 x absorber groups u-shaped installation

Lower edge soil collectors227,15 m NHN

Terrain‘s top edge (after backfilling)Cap

Measuring rod with metric scale

Drainage pipe DN100 with fleece cover

Bentonite barrier layer

Top edge of groundwater

„This project has received funding from the Eurpean Union´s Horizon 2020 research and innovation programme under grant agreement No 768292“

Contact data

GeoCollect GmbH Borssenanger 10 D 09113 Chemnitz

Tel.: +4937133782475 Fax: +4937133782476 Mobil:+491709209790 Mail: vertrieb@geocollect.de www.geocollect.de

Geschäftsführer:Kai-UweWohlers Handelsregister:AmtsgerichtChemnitz·HRB:Nr.32134 USt.-ID:DE815332719