T E C H N I C A L I N F O R M AT I O NGround Energy
2 UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 3Contents:Introduction •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 4Ground Energy – in brief •••••••••••••••••••••••••••••••••••••••••••••••••••• 5Hot stuff – Planet earth – a source of energy •••••••••••••••••••••••••••••••••• 6BasicsGeneral ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 8Heat pump system ••••••••••••••••••••••••••••••••••••••••••••••••••••••• 9Ground Energy SystemsSystem overview ••••••••••••••••••••••••••••••••••••••••••••••••••••••• 20Operating modes ••••••••••••••••••••••••••••••••••••••••••••••••••••••• 21Horizontal CollectorsSystem/scope of application •••••••••••••••••••••••••••••••••••••••••••••• 24Energy CagesSystem/scope of application •••••••••••••••••••••••••••••••••••••••••••••• 32Energy PilesSystem/scope of application •••••••••••••••••••••••••••••••••••••••••••••• 41Vertical CollectorsSystem/scope of application •••••••••••••••••••••••••••••••••••••••••••••• 56Uponor quality materialsPE-Xa•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 63Quick & Easy •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 65Project planningProject scheduling •••••••••••••••••••••••••••••••••••••••••••••••••••••• 66Detailed planning••••••••••••••••••••••••••••••••••••••••••••••••••••••• 68
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/20124Ground Energy has a number of beneﬁtsRenewable: Ground energy is available endlessly, 24 hours a day forheating and cooling.Environmentally friendly: Any usage of ground energy reduces theemissions of greenhouse gas.Safe and controllable: Ground energy is technically mature and hasbeen used for heating and cooling for more than 50 years.High performance: a response to all energy demands such as heat-ing, cooling, hot water and energy storage.Versatile: applicable in combination with other energy sources.Economically sustainable: regionally usable, independent of exter-nal suppliers and changes in currency exchange rates.Securing the competitiveness: Ground energy increases the indus-trial competitiveness and as a result has a positive effect on theregional development and employment.IntroductionGround Energy – Independence of the energy situationGround Energy – versatile useGovernments across Europe havethe ambitious goal of reducing theenergy consumption in order toreduce the dependence on fossilfuels such as oil and gas. Renewa-ble energy sources like solar energyand ground energy increasingly gainimportance with respect to thefuture energy demand in buildings.With the 20-20-20 target the EUplans to reduce the energy consump-tion and greenhouse gas emissionby 20 % until 2020 and to increasethe use of renewable energy sourcesto 20 % (2007: 8.5 %) of the ener-gy mix. Therefore various legislativeinitiatives have been started allover Europe to promote the use ofrenewable energy sources.Ground energy cannot only be usedas source of energy for radiantheating and water heating but alsoas an energy source for radiantcooling with very low operatingcosts. Ground energy can be usedin all types of buildings fromsingle-family houses to large ofﬁceand industrial buildings.When a ground system is operatingit hardly requires any running costsand has a long operating period.Though the investment costs for aground energy system are slightlyhigher than for conventional boilersand cooling aggregates the amorti-zation period is shorter due to thelow operating costs.Ground energy as energy sourcein combination with radiant emittersystems is the all-in-one solutionwith respect to the combination ofheating and cooling.Such systems are more efﬁcientand easier to install than two sep-arate systems for heating andcooling.In addition, the radiant emittersystems benefit from the exergyprinciple in the form of reductionof the operating temperatures forheating and high operating tem-peratures for cooling. Thus theheat pump can work with a higherefficiency (operating factor)which reduces the power consump-tion and hence the operatingcosts accordingly.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 5Ground Energy – in briefFields of application / usagesHeatingHot waterCoolingEnergy storageEnvironmental aspectReduces the use of fossil fuelsReduces the CO2emission, whereapplicableRenewable energy sourceWhen installed and used properlyno adverse effects on groundwa-ter and soilFields of applicationSingle-family homes and apart-ment blocksPrivate and public buildingsIndustrial buildingsOfﬁce buildingsTechnical aspectsGround energy is available almostunlimited all-the-yearNo chimney requiredFully automatic safe operation, lowmaintenanceDistributed and central system usageCan be combined with otherenergy sourcesEconomic aspectsLow operating expenditures(power required for heat pump,but no fuel costs)Low cost of ownership (no emis-sion measurements, no costs forchimney sweep)No fuel supplies requiredComparatively high investmentcostsAmortization dependent on thegeneral development of energycostsEfﬁciency dependent on properlayout of the complete systemand electricity tariffs (“heat pumppower“) of the energy suppliersGeothermy (Greek: geo = earth; thermy = heat)or ground energy is the heat stored in the accessi-ble part of the earth crust. Geothermy describesboth, dealing with thermal energy and its utiliza-tion from a technical point of view and the scien-tiﬁc investigation of the thermal situation of theEarth.Visible thermal heat – Hot spring on Iceland
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012The crust of the earth in compari-son to the diameter of the earthof about 12,750 km is only a thinlayer. Below the oceans the crusthas a thickness of approximately 5to 10 km, below the continents ithas a thickness of 15 to a maximumof 50 kilometers. High temperaturesprevail already in the crust; at thecrust’s bottom side up to 1,100 °C.Below the crust there is the mantlewhich according to petrophysi-cal characteristics is split into theupper and lower mantle and atransition zone. The upper mantlespreads to a depth of approxi-mately 400 km with temperaturesof up to 1,400 °C, the transitionzone spreads to up to 900 km andthe lower mantle to a depth of2,900 km with temperatures of upto 3,700 °C.Below 2,900 km begins the earthcore with an outer liquid core andan inner solid core. In the outercore temperatures of approximately4,000 °C prevail, in the innercore probably more than 5,000 °C.Hot Stuﬀ: Planet Earth – the Energy SourceShell structure of the earthCrust(approx. 30 km)approx. 3 °C/100 mMantle> 1.200 °CCoreapprox. 5000 °CAt present the economic useof geothermal energy is limitedto the upper part of the crust.A distinction is made betweenground energy collectors anddeep geothermal energy.6 UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012
7Geothermal EnergyGeothermal energy is further dividedinto two applications or systems:hydrothermal and petrothermal sys-tems.Hydrothermal MethodWith the hydrothermal method natu-rally occurring thermal water resourc-es (hot water aquifers) are tapped.These aquiferous layers can be usedfor both direct (heat) and indirect(electricity) energy generation.Petrothermal MethodWith the petrothermal method ener-gy is generated from hot dense rock.The Geothermal energy can be uti-lized by means of the so-called hot-dry-rock-method. The rock exploitedby drilling in a depth of some thou-sand meters is fractured by waterstreaming in under very high pres-sure resulting in hydraulic routing.The subterraneous “heat exchanger“generated this way now directs theenergy in the form of water vaporupwards through another borehole,where it either drives turbines togenerate electricity or is used fordirect heat generation.Ground EnergyWe speak of ground energy incase of application depths of up to400 m. Here, the temperatureincreases by 3 °C per 100 m depthon average. The average surfacetemperature of the earth is approx-imately 13 °C and is determinedthrough a combination of irradiat-ing solar energy, emission of heatinto space, ground ﬂux and variantsor interferences of these factors.In contrast to geothermal energythe ground energy does not pro-vide energy directly in the form ofusable heat. For heating and hotwater generation the temperaturelevel must be increased to therequired value through a heatpump.Apart from the depth and the typeof rock also groundwater plays animportant role in energy generation.In Central Europe the groundwaterhas an almost constant temperaturethroughout the season. Due to thepermanent ﬂow heat energy isconstantly supplied for heating ordissipated for cooling.Even in case of outside tempera-tures that seasonally vary consider-ably the temperature in a fewmeters depth remains relativelyconstant at an average of 10 °C.Hence, ground energy is a perma-nently functioning or constantsource of energy that enables useover the whole year both forheating and cooling of buildings.UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/20128When planning the use of groundenergy local conditions are of funda-mental importance. Determiningthe soil properties with respectto the water content, the thermalground soil characteristics, i.e.thermal conductivity, density, spe-ciﬁc and latent thermal capacity aswell as evaluating the differentheat and substance transport pro-cesses are pre-requisites to deter-mine and deﬁne the capacity ofa ground application. The dimen-sioning of the ground energyGeneralsource has great impact on theenergy efﬁciency of a heat pumpsystem. Heat pumps with a highcapacity have unnecessary highpower consumption when com-bined with a poorly dimensionedheat source.Region with highground energypotentialBasics
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 9A heat pump system is an energysystem comprising a heat source, aheat pump and a heat utilizationsystem.Heat SourceHeat sources for the pump systemcan generally be air, water andground soil. One speaks aboutground utilization when ground soilis used as heat source. For theextent of ground utilization mainlygeology, hydrology and the climaticconditions and thus the ability forregeneration of the ground soil areof primary importance.Geology, Hydrology and ClimateSoils usually have a pore share of35 and 45 %. If these are ﬁlled withwater instead of air, the heat con-ductivity, the density and the spe-ciﬁc and latent heat capacity ofthe soil increase. This has a positiveeffect on the maximum possibleabstraction capacity of a groundcollector.The water content of the soildepends on the climatic conditions,the cultivation, the groundwaterlevel and the hydraulic characteris-Heat Pump SystemΨGes= ΨM+ ΨG= 0 [Vol. %]tics (capillarity) of the ground soil.The water contents of the soil aremainly inﬂuenced the effects of thecapillary rise from the groundwaterlevel and the moisture penetrationdue to seeping rain water.The matrix potential ΨM(suctionpressure) of a soil describes theextent to which existing water isbound in the soil matrix. The lowerthe water content the more theremaining water is bound to thesoil matrix. Mainly the gravitationpotential ΨG(dynamic pressure)or geodetic height above thegroundwater level as well as neg-ligently the osmotic potential,the surcharge load potential andthe pressure potential workagainst the matrix potential. Inthe stationary state both poten-tials even out.VolumetricwatercontentMatrix potential or height above groundwater [m]Stationary water content subject to the height above groundwaterlevel0.1 1001022.214.171.124.350.4126.96.36.199.050.25SandLoamSiltSilty clayloamClayHeat pump systemHeat sources:AirWaterHeat pumpHeat utilizationsystemGround soil
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201210Apart from the height abovegroundwater the average rain waterquantity seeping into the soil overa longer period of time has a greatimpact on the water content ofthe relevant soil. Short showers thatcause a surface runoff have hardlyany inﬂuence.The higher the water content of thesoil the better the soil allows waterto seep in (groundwater permeabi-lity). With relatively steady rain overa longer period of time the watercontent in the soil rises until therain water can seep in due to gravi-tation.The monthly water quantity seepinginto the ground results from thedifference between rainfall andevapotranspiration (evaporationplus transpiration of the plants).The characteristics of the soil duringthe heating period are mainly in-ﬂuenced by the months of Octoberand November. During thesemonths the plant growth and theaverage outside temperature isdecreasing, thus the evaporationrate will decrease as well.Actually the course of rainfall is notvery stationary. This is dampenedin the top earth layers by the soilcapacity and the groundwater per-meability dependent on the watercontent to an extent that in the rel-evant soil only long-term changesof rainfall affect the water content.Thus the water content in the rele-vant soil materializes from rainfallaveraged over several weeks.The soils commonly found in natureare mixtures of sand, silt and clay.They comprise the three phases –solid matter, water and gases – thedensity, heat conductivity as wellas speciﬁc and latent heat capacityare based on. These characteristicsare very difﬁcult to determine dueto the many variances and can bestbe taken from respective referencecatalogues for different climaticregions.Information:The speciﬁc heat conductivity λ [W/(K · m)]describes the ability of a rock to transport thermalenergy by means of heat conduction (conductiveheat transport). It is a temperature-dependentmaterial constant.The speciﬁc heat capacity cp[MJ/(m³ · K)]speciﬁes the energy quantity that is needed toheat 1 m³ of the rock to 1 K.The bigger it is the more heat energy the rock canabsorb (store) and eventually release.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201212Groundwater with its high heatcapacity of 4.190 J/kgK at 10 °Cplays an important role for theabstraction capacity of the groundsystem. With respect to thegroundwater permeability a dis-tinction is made between the poreOn average the temperatureincreases by 3 °C per 100 m depth.The course of the temperaturesduring the year (Central Europe) inpermeability and the joint permea-bility with respect to the sub-sur-face of unconsolidated rock or sol-id rock. With unconsolidated rock(pore aquifer) especially the grainsize and grain distribution, andin case of solid rock the frequencythe upper 15 m is shown in theillustration below. In the Winter theoutside temperatures may oftengo below zero degrees, but in a fewUnconsolidated rock Coefﬁcient of hydraulic con-ductivity kf[m/s]Evaluation of the permeabilityPure gravel above 10-2highly perviousSandy gravel,medium/ torpedo sandabove 10-4to 10-2highly perviousFine sand, silty sand above 10-6to 10-4perviousSilt, clay loam 10-8to 10-6slightly perviousClay, silty clay below 10-8imperviousReferencevalues for thepermeability ofunconsolidatedrockmeters depth the soil temperaturealready reaches a value of 10 °Con average. In the Summer the out-side temperature is almost 20 °Con average, the ground soil in a fewmeters depth, however, showsalmost constant temperatures of10 °C. This applies in most cases forthe transition periods of springand fall.From the course of the shallow soiltemperatures over the year itbecomes apparent that groundenergy is an always functioning andconstant source of energy.and opening width of the separat-ing joints are decisive for thegroundwater permeability. Thetable below shows reference valuesfor the permeability of unconsoli-dated rock.Source: VDI 4640Depthinsoil[m]Temperature (depth) [°C]On average the soil temperature increases by 1 °C approximately every 33 m.0 205 10 1520015105Temperature (earth’s surface) [°C]0 205 10 151. February 1. May 1. November 1. August
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 13The cycle running within the heatpump consists of four compo-nents: the evaporator, the com-pressor, the condenser and theexpansion valve. The carrier forthe thermal energy is a refrigerantwith an extremely low boilingpoint. In the evaporator the refrig-erant takes up the heat from theenvironment and thus becomesgaseous.In the compressor the gaseousrefrigerant is brought to a highertemperature level by compression.To do so, the device needs theexternal electrical power.In the condenser the thermal ener-gy is supplied into the heatingcircle. In the expansion valve therefrigerant is expanded in orderto pass through the circle againafterwards.Heat pumps are categorizes asfollows:air/water heat pumpswater/water heat pumpsbrine/water heat pumpsThe designation of the heat pumptype depends on which mediumabsorbs the heat (heat transfermedium) and which medium distrib-utes the heat in the house.If brine (water / glycol mixture)absorbs the heat through a groundcollector and if water dissipates theheat e.g. through an underﬂoorheating system, this is called abrine/water heat pump.Heat pumps are cold vapor machinesby means of which low temperatureambient energy can be utilized forheating or cooling buildings. Theambient energy is extracted from theambient air, the groundwater orHeat Pumpsthe ground soil. By using electricalpower the temperature is brought tothe desired level.CompressorCondenserEvaporatorExpansion valveHeatingsystemFunction principle ofa heat pump
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201214With respect to the operating modes a distinction is made between:monovalent (one energy source)bivalent (two energy sources)monoenergetic (one energy resource).Air/water heat pumps are directlysubject to ﬂuctuations of the outsidetemperatures. Thus they have thelowest energy efﬁciency in timeswhen the heat demand is the high-est – in the Winter when the ambi-ent air has the lowest energy con-tent. In order to cover theseextreme cases, with the air/waterheat pump the peak loads caneither be accommodated monoen-ergetically through an additionalelectric heating (heating rod) orbivalent through a second energysource (e.g. solid fuel boiler).Temperature[°C]Days20-1515105-50-10Dimensioning point100 %Heat pump with mono-valent operating modeTemperature[°C]Days20-1515105-50-10Dimensioning point> 95 %-3Heat pump with mono-energetic operating modeTemperature[°C]Days20-1515105-50-10Dimensioning point> 60 %3Heat pump with bivalent-parallel operating mode
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 15For ground applications brine/water heat pumps are used. In thistype of pump a water/glycol mix-ture ﬂows through the heatexchanger. In order to assess thequality of a heat pump system theso-called seasonal performancefactor β is used. It shows the ratioof heating energy delivered to elec-trical energy supplied (rated capac-ity) over one year.Overview of heatpump systemsThe higher the seasonal perfor-mance factor the higher theefﬁciency of the heat pump. Theusual range is 3 to 4.5.Seasonal performancefactor β=W (usable thermyl energy)W (supplied electrical power)To be able to evaluate the energyquantity or capacity that can beextracted from or supplied to theground by a heat exchanger, criteriamust be deﬁned by means of whichthe efﬁciency can be measured andwith which limit values must notbe exceeded.The following criteria must be metto ensure that the heat pump sys-tem is not damaged:Operational safety is understoodas preventing damage of the systemand complying with the maximumcapacity of a heat pump to ensurethat safe operation can be guaran-teed over the whole year. Withrespect to the heat source thismeans that the brine neverfalls below the solidiﬁcation tem-perature and the minimum brinetemperature speciﬁed by the heatpump manufacturer.The brine is cooled down in theevaporator before it heats up againin the heat source. Thus, there arethe lowest temperatures in thebrine circuit. The common heat car-riers that contain water expandduring solidiﬁcation. Hence here isthe danger that pipes or the evapo-rator burst, if the brine solidiﬁes.The heat carriers mainly used forheat sources are mixtures of waterEnsuring the operational Safetyand glycol (mainly monoethyleneglycol). With the establishedmixing ratio of 3:1 a protectionagainst freezing to approx. -14 °Cis guaranteed. Therefore it mustbe ensured not to fall below thistemperature at any point. For thisreason most manufacturers haveintegrated safety devices so thatthe heat pump is switched offearly. This function can forinstance be taken over by a LPpressure control switch positionedin the suction line leading to thecompressor. When falling belowthe pressure which corresponds toan evaporation temperature ofapprox. -15 °C or in case of over-heating which corresponds to aHeat utilization systemHeat pumpHeat sourcesHeat exchangePanel heating and cooling systems suffused with waterbrine/waterheat pumpwater/waterheat pumpair/waterheat pumpGround soil Water AirHorizontal collector- vertical collectorGroundwater- surface watersSurrounding air
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201216Gas Heat pumpRequired heat energy [kWh] 20,000 20,000Efﬁciency/Seasonal performance factor 85% 4Energy quantity obtained [kWh] 23,529 5,000Price per kWh [ct/kWh] 6.68 13.61Basic price [¤/year] 142.8 41 ,40Operating costs [¤/year] 1,714.56 721.90Costs exhaust gas measurement [¤/year] 45.11 –Total cost [¤/year] 1,759.65 721.90Difference [¤/year] – 1,037.75Costs in per cent 100% 41%suction gas temperature of -10 °C,the pressure control switch causesthe heat pump to switch off.Depending on the heat transfercharacteristics of the evaporatorand of the temperature spreadin the brine circuit a suction gastemperature of -10 °C corre-sponds to a brine return tempera-ture of approx. -5 °C.Due to the safety reasons men-tioned above and partly dueto the maximum possible pressureratio of the compressor this tem-perature is speciﬁed as the limitby most heat pump manufactur-ers. Therefore, the heat sourcesystem has to be laid out so thatthe brine return temperatureinto the heat pump does not fallbelow -5 °C also during peakloads in the Winter.The table below shows an exam-ple of a calculation of the costof ownership of a heat pumpcompared to a traditional heatingsystem.Exemplary comparison of cost of ownership in Germany
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 17Low temperature systems are espe-cially suited to operate togetherwith heat pump systems. Due tothe large surface the required oper-ating temperatures are only slightlyabove (heating) or below (cooling)the room temperature which con-siderably improves the energy efﬁ-ciency of heat pumps used forground energy systems.Low-temperature systems includeradiant heating and cooling sys-tems in which water is circulated:underﬂoor heating and coolingsystemwall heating and cooling sys-temsceiling heating and coolingsystemsIn radiant heating or cooling sys-tems the energy is almost exclu-sively transferred through radiationand not through convection. Thusdrafts and stirring up of dust areavoided. Since radiant heating andcooling systems are “invisible” theydo not take up valuable space andoffer almost unlimited freedomwith respect to the design and fur-nishing of rooms as well as anoptimal ratio of interior space andusable space.Underﬂoor heating and coolingSystemsThere are tailormade system solu-tions not only for new buildings butalso for retroﬁtting existing ﬂoors.To increase comfort these systemscan also be used for interior cool-ing. When planning ahead thecooling function can be retroﬁttedlater.Underﬂoor heating and coolingsystems are installed in differentways. The most typical types fornew buildings and renovation are:Low height systemsWet systemsDry systemsWall heating and coolingSystemsAs an alternative to underﬂoorheating or cooling systems or toextend the heating or coolingsurfaces wall systems can be used.A distinction is made between:Dry wall systemsWet wall systemsDry wall systems are used for reno-vating, if the ﬂoor construction isnot to be changed or must not bechanged. Apart from existing wallsadditional lightweight constructionswalls (stud walls) can be used asheating or cooling surfaces.Depending on the wall constructionthe system is installed below thepanelling or directly in the plasterlayer. Wet wall systems are used incase of partial renovating or whennew plaster is applied.Ceiling heating and coolingSystemsHeating and cooling in the form ofceiling heating and cooling systemsis increasingly used for reasons ofHeating emitter systemscomfort and efﬁciency comparedto air conditioning systems.With ceiling heating and coolingsystems a distinctin is madebetween the following types:Suspended ceilings or ceilingpanelsActivation of thermal mass orconcrete core activationSuspended ceilings are used innew builds and renovation. Heat-ing and cooling in ceiling panels isactivated by installing pipes inwhich water is circulated directly inthe ceiling panels.Concrete ceilings are used forcooling or heating of multi-storybuildings. This future-orientedsolution results in thermally activeceilings by means of pipe registersin which water is circulated alsoin module construction. Concretecore activation is used to ensurethermal comfort in the building ina simple, environmentally friendlyand cost-saving way. Concretecore activation should be used forbuildings with low or mediumcooling loads in order to workagainst heating-up in the Summer.In buildings with medium orhigh cooling loads the concretecore activation can be used tocover the basic loads.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201218Uponor WallUponor ContecUponor MinitecUponor Horizontal Collectors Uponor Energy Cages Uponor Energy Piles Uponor Vertical Collectors
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 19Uponor ClassicUponor SiccusUponor Klett / VELCRO
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201220Ground Energy utilization SystemsWith ground energy collectors (heatexchangers) a distinction is madebetween Horizontal and verticalcollectors.Conventional ground energy sys-tems can be classiﬁed as follows:HorizontalHorizontal collector or surfacecollector (earth-to-air heat ex-changer)Spiral and energy cagesRift collectorsVertikalBoreholesEnergy piles and slotted wallsSystem OverviewThe suitability of the respectiveground energy system depends onthe environment (soil propertiesand climatic conditions), the per-formance data, the operatingmode, the type of building (com-mercial or private), the space avail-able and the legal regulations.Horizontal CollectorsHeat exchangers that are installed horizontally or diagonally in the upperﬁve meters of the ground (surface collector). These are individual pipecircuits or parallel pipe registers which are usually installed next to the build-ing or under the ground slab.Energy PilesHeat exchangers in pile foundations that are installed in areas with insufﬁ-cient load capacity. Individual or several pipe circuits are installed in founda-tion piles in U-shape, spiral or meander shape. This can be done with pre-fabricated foundation piles or directly on the construction site where thepipe circuits are placed in prepared boreholes that are then ﬁlled with con-crete.Vertical CollectorsHeat exchangers that are installed vertically or diagonally in the ground.Here one (single U-probe) or two (double U-probe) pipe circuits are insert-ed in a borehole in U-shape or concentrically as inner and outer tube.Energy CagesHeat exchangers that are installed vertically in the ground at lower levels.Here, individual pipe circuits are arranged in spiral or screw shape. Energycages are a special form of horizontal collectors.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 21Heating operationCooling operation (active)Cooling operation (passive/free cooling)Operating modesThe operating mode and the resulting operating cost of the heat pump are deﬁned according to the heating andcooling requirements of the respective building.Ground energy is used as heat sourceThe heat pump increases the media temperature to alevel utilizable for the building.Ground energy is used as heat sinks (cooling source)Temperature level for passive cooling insufﬁcientCompressor activeDual operation possibleGround energy is used as heat sink (sold source)Temperature level from ground energy sufﬁcient forpassive cooling – only circulation pump is activeNo dual operation possibleVery low operating costsElectrical energyGround energyHeating systemCooling systemElectrical energyGround energyHeating systemCooling systemElectrical energyGround energyHeating systemCooling system
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201222Ground energy is the only systemthat enables so-called passive cool-ing or free cooling. Vertical collec-tors are the most effective solutionof all potential applications forthis operating mode.A pre-requisite for this is the useof a radiant heating or coolingsystem.The “free cooling” operating modehas several advantages for the userand the environment:Increased living comfort due toan agreeable room climateImprovement of the seasonalperformance factor of the wholesystem by regeneration of theground soilMinimum additional investmentcosts, low operating costsSaved resourcesEnvironmentally compatibleDue to the improved insulation ofnew buildings the ratio of heatingand cooling changes. Where in thepast the focus was on heating,now cooling is more in the focusdue to increased demands forcomfort. Modern buildingsincreasingly tend to overheat inwarmer periods of the year. Towork against this effectively shad-ing measures are taken. Toachieve an operative room tem-perature (comfort temperature) of26 °C, the cooler temperaturesstored in the ground is used andtransferred to the buildingthrough a radiant system.By discharging excess heat fromthe building into the ground theground is actively regenerated,i.e. it heats up again. In singlefamily houses more heat isextracted from the soil in theWinter than is resupplied in theSummer. This can be regarded asunproblematic since usually dur-ing the transition from heating tocooling period there is sufﬁcienttime for the passive or naturalregeneration. The active regener-ation supports this additionally.When using passive cooling onlyminimal additional investmentcosts arise. Monitoring of thedew point and switching overfrom heating to cooling can betaken over by modern regulatingor radiant heating and coolingssystem, like for instance theDynamic Energy Management(DEM). Additional costs onlyoccur for the dew point sensorsHeating and cooling – dual operationDepending on the energy balance in the building theground energy is used as heat source and heat sink(cold source)Mode of operation Heating CoolingActive Passive / Free CoolingSystem size < 30 kW > 30 kW < 30 kW > 30 kW < 30 kW > 30 kWVertical Collector ● ● ● ● ● ●Horizontal Collector ● ●● ● – ● –Energy Cage ● ● ● – ● –Energy Pile ● ● ● ● ● ●Selection matrix of ground energy systems depending on the operating mode and system size● applicable ● limited use dependent on the general conditionsPassive cooling – free coolingElectrical energyGround energyHeating systemCooling system
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 23Operative room temperature usingpassive coolingThe use of the passive cooling function resultsin a clear improvement of the operative roomtemperature.Example calculation – potential annual costs – passive coolingExample calculation – potential annual cost – active coolingBrine circulation pump Emitter circulation pumpEl. power 5 – 70 W 16 – 310 WEl. power with calculated ﬂow rate 60 W 55 WOperating time 800 h 800 hTotal annual energy demand 48 kWh 44 kWhElectricity tariff per kWh 0.20 ¤/kWh 0.20 ¤/kWhAnnual energy costs 9.60 ¤ 8.80 ¤Total energy costs 18.40 ¤Compressor Emitter circulation pumpEl. power 2,300 W 16 – 310 WEl. power with calculated ﬂow rate – 55 WOperating time 800 h 800 hTotal annual energy demand 1,840 kWh 44 kWhElectricity tariff per kWh 0.20 ¤/kWh 0.20 ¤/kWhAnnual energy costs 368.- ¤ 8.80 ¤Total energy costs 376.80 ¤Operative room temperature withoutusing passive coolingThe illustration on the left shows the courseof the temperature inside a room with outershading on a typical summer day in July.Overheating of the room is obvious.Operativeroomtemperature[°C]Time [h]Operative room temperature without using passive coolingOperative room temperature in the course of a dayOptimal operative room temperatureUsual range of the operative room temperature151617181920212223242526270 01 2 3 4 5 6 7 8 9 10 11 12 13 14 1615 17 18 19 20 21 22 23Operativeroomtemperature[°C]Time [h]Operative room temperature without using passive coolingOperative room temperature in the course of a dayOptimal operative room temperatureUsual range of the operative room temperature0 01 2 3 4 5 6 7 8 9 10 11 12 13 14 1615 17 18 19 20 21 22 23151617181920212223242526272829and mounting. In case of passivecooling only the brine circulationpump and the emitter circulationpump of the system are operat-ing. The heat pump compressordoes not run. Thus the operatingcosts are limited to the powerconsumption of the circulationpump(s).
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201224Application descriptionHorizontal collectors are the mostwidely used variant of ground ener-gy exchangers. They consist of hori-zontal pipes, i.e. pipes laid in paral-lel to the surface of the earth.The important beneﬁt of the hori-zontal collectors is the low invest-ment with a relatively high seasonalperformance factor. Of all groundenergy systems the horizontal col-lector is the variant with the lowestcosts involved. A relatively largespace of unsealed garden is to beplanned.An alternative to the horizontal col-lectors is the activation of the foun-dation slabs for heating and/or pas-sive cooling. Here, no additionalspace apart from the actual buildingis required. Since most buildings arebased on foundation slabs, stripfoundations or deep foundations ora combination therefore, utilizationof the ground energy heat throughthe foundations would be useful.Below the foundation slab or ﬂoorslab, i.e. between ground soil andslab usually a so-called blindinglayer is integrated which consistsof lean concrete or ﬁne gravel. Toutilize the ground energy collectorpipes can be integrated here.The capacities that can be reachedwith foundation slabs are limitedand clearly lower than with horizon-tal collectors that are not overbuilt;Here apart from the soil conditionthe groundwater level and ground-water ﬂux are of fundamental impor-tance. Temperatures below thefrost level are to be avoided in anycase!System/scope of applicationSchematic illustration of a horizontal collector systemBeneﬁtsComparably low investmentcostsGood seasonal performancefactorEasy installationIdeal solution for singlefamily or multi-family housesas well as small business andindustrial applicationsLow installation depth with-out affecting the hydrologicbalanceDepending on the respectiverequirements and conditions theindividual pipe loops are laid atdistances of 0.5 to 0.8 m (with pipediameters of 40 mm 1.2 to 1.5 m) –similar to the pipe loops of anunderﬂoor heating system. The sup-ply and return pipes of the individu-al pipe loops are combined in col-lecting and distribution chambers ormanifolds and routed to the heatpump.Note:Combining horizontal col-lectors with the UponorEPG6 cooling station makesan ideal free-cooling solu-tion.Horizontal Collectors
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 25Fixing of the pipe loops on reinforcement meshLaying of the individual pipe loopsFunctioningUp to 99 % of the heat extractedfrom the ground soil by horizontalcollectors is solar energy storedin the ground soil and not groundenergy from the earth core. Forthis reason the thermal contactwith the surface of the earth isdecisive for the efﬁciency.In the Winter the net solar energyhitting the ground soil is the lowest,but the extraction of heat ofground energy collector by meansof heat pumps is the highest. Theextracted energy is the solar ener-gy stored in the ground soil duringsummer. The basic storage capacityof the ground soil can be put downto the phase change of the waterexisting in the ground soil. In orderto enable a horizontal collectorto utilize this storage capacity it isnecessary that the top edge of thecollector which can have any shapeis positioned below the naturalfrost line.Physical properties of the characteristic soil typesUnit Sand Clay Silt Sandy clayWater content % Vol. 9.3 28.2 38.1 36.4Heat conductivity W/mK 1.22 1.54 1.49 1.76Speciﬁc heatcapacityJ/kg K 805 1,229 1,345 1,324Density kg/m³ 1,512 1,816 1,821 1,820Source: VDI 4640Depthinsoil[m]Temperature (depth) [°C]On average the soil temperature increases by 1 °C approximately every 33 m.0 205 10 1520015105Temperature (earth’s surface) [°C]0 205 10 151. February 1. May 1. November 1. AugustUponor Horizontal Collector Installation depth: usually 1.2 – 1.5 m
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201226During longer operating periods both the speciﬁc abstraction capacity q and the speciﬁc annual abstraction factor are to be considered.For ground energy collectors this should be between 50 and 70 kWh/(m² year). Reference value for ground energy collector training according to VDI 4640:valid for heating operation and water heating only!Reference values for the dimensioning of horizontal collectorsSubsurface Speciﬁc abstrac-tion capability qEwith 1.800 h/a[W/m²]Speciﬁc abstrac-tion capability qEwith 2.400 h/a[W/m²]Installationdistance[m]Installation depth[m]Distance tosupply pipes[m]Dry, non-cohesive soils 10 8 1 1.2 – 1.5 > 0.7Cohesive soils, damp 20 – 30 16 – 24 0.8 1.2 – 1.5 > 0.7Water saturated sand/gravel 40 32 0.5 1.2 – 1.5 > 0.7Application limitsThe efﬁciency of a horizontal col-lector mainly depends on the watercontent of the surrounding groundsoil. In sandy soil with its low capil-lary action, rainwater seeps quicklyinto deeper earth layers. Clay soilwith a high capillary effect, howev-er, can keep the water much betteragainst gravity. These differencescause the volumetric water contentof sand to be usually below 10 %and that of clay to be above 35 %.Thus in clay more than double theamount of water per ground soilvolume is available as latent storagefor a horizontal collector than insandy soil. In addition, water con-tained in the ground soil improvesthe heat conductivity, wherebystored heat from deeper earth layersand the solar energy of the earth’ssurface can ﬂow much easier to thecollectors.In the table on the previous pagea distinction is made between sand,clay, silt and sandy clay whichreﬂect the wide spectrum of soilsexisting in nature very well.Sand in this context is loose soilconsisting of individual grains(> 50 mm). In this type of soil thecapillary effect is extremely lowand the groundwater permeabilityis high. Thus rainwater seeps quicklyinto deeper layers which abovethe groundwater results in a low vol-umetric water content below 10 %.Clay mainly consists of a mixtureof sand and silt, while silt is a soilwith medium-ﬁne graininess(between 2 mm and 50 mm). Thesecohesive soils usually have volu-metric water contents between 20and 40 % and are therefore bettersuited for horizontal collectorsthan sand.In sandy clay of which the biggestfraction consists of very ﬁne grains(< 2 mm) the capillary effect is evenhigher resulting in volumetric watercontents above 30 %.The exact physical properties varyfrom place to place which amongother things is caused by differentprecipitation amounts. The followingtable shows the mean values ofthe physical properties of the dif-ferent soil types.Within Europe the climatic differ-ences are so big that it does notmake sense to lay horizontal collec-tor according to the same rules. Inwarmer climes a higher surface-spe-ciﬁc abstraction capacity is possiblewithout causing damage of the sys-tem or the environment.Building and the environmentDuring heating the horizontal collec-tors extract heat from the groundsoil, so that afterwards it cools downto below the temperature of theundisturbed ground soil. Whendimensioning systems it is to beensured that the surrounding groundsoil and the environment are notheavily affected or damaged.In general it is possible that the ﬂoraabove a horizontal collector developsslightly delayed in the Spring. Sincethe horizontal collector is usuallypositioned in depths below onemeter and only few roots of beddingplants drift into this depth, theeffect is low. In principle any type ofplant can be planted on the horizon-tal collector ﬁeld, even trees. Groundenergy pipes in the usual depth can-not be damaged by roots and theeffect on the plants caused by pipesis minimal.It is not the sensitive cooling butrather the ice formation in the Win-ter that can cause damage. Whenfalling below the pipe surface tem-perature of 0 °C the water existingin the surrounding ground soil startsto freeze. Slight ice formation usuallyis not problematic, since in the Win-ter also the undisturbed ground soilfreezes up to a depth of 0.5 m – 0.8 mand melts with rising temperatures
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 27in the Spring. However, due to twoeffects ground soil or the environ-ment might be negatively affected incase the ice formation is too heavy.Expansion of the water duringfreezingThe water existing in the pores ofthe ground soil extends its volumewhen freezing. If only relatively fewpores are ﬁlled with water the iceformation does not have remarkableeffects, since the ice can thenexpand into the adjacent poresﬁlled with air. However, when thewater content is high, stress occurswith different consequences.First the water close to the collectorfreezes and expands. Due to theexpansion the ground soil aroundthe collector pipe is pressed to theoutside. Especially loamy soils keepthis shape even after the ice hasmelted in the Spring. Thus the ther-mal contact between the collectorpipe and the ground soil is interrupt-ed. Only by increased rainfall can thespace in between be ﬁlled again.Water damage in the SpringWhen the radii of ice around theindividual collector pipes growtogether the vertical humiditytransport is interrupted. Then themelting water formed in the Springand the increasing amount of rain-water cannot seep into theground. Mud is produced on theearth’s surface. Especially on steephills continuous ice layers belowwaterlogged soil can cause land-slides. However, with a groundslope of up to 15 % the horizontalcollector can be installed in paral-lel to the surface of the earthwithout problems.It has to be considered that iceradii that potentially grow togeth-er melt down in the Spring ontime to ensure that the water canseep into the space. Since theannual course of temperatures andthe start of vegetation in theSpring are regionally very differentit is not useful to ﬁx a due datefor this. Instead the point of timewhen the average ambient tem-perature over two to four dayreaches a limit temperature of12.0 °C is considered appropriate.This point of time usually isbetween the middle of April andthe middle of May. Until thenthe ice radii should have melteddown to an extent that they arenot longer in contact with eachother. Then the water seeping inaccelerates the further melt down.The effects of water damage areespecially high in case of well sat-urated sandy soils close to thegroundwater level, since withthese soils usually the water canseep in easily and the ice layerwould hinder the natural drainage.In clayed soils the water onlyseeps in slowly also when they arefrozen which is why a closed icelayer has a minimal effect on thenatural drainage. When dimen-sioning the horizontal collector inaccordance with VDI 4640 envi-ronmental effects are not to beexpected.Generation of a ﬂoor slab collectorCollector pipe loops made of PE-Xa
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201228Apart from the soil properties andclimatic conditions the dimension-ing of horizontal collectors dependson the annual operating hours ofthe heat pump system. Usually amaximum of 1800 h operatinghours is assumed.The required collector area for hori-zontal collectors is based on thespeciﬁc abstraction capacity qEofthe soil and the refrigerant capacityQOof the brine/water heat pump.Amin= [m²]QOqEThe refrigerant capacity corre-sponds to the capacity share of theheat pump extracted from the envi-ronment and forms the differenceof the heating capacity QHand theelectric power consumption Pel.The required collector pipe lengthLKis calculated out of the requiredcollector surface Aminand the dis-tance s of the collector pipes.QO= QH– Pel[W]LK=Amins[m]Dimensioning of Horizontal CollectorsWhen reducing the pipe distancewhile maintaining the same abstrac-tion capacity there is principally therisk of mud formation in the Spring.The ice radii around the pipes wouldthen not melt in time, in order toprovide space for the rainfall to seepin. When increasing the pipe dis-tance the brine temperaturedecreases for the same heat extrac-tion. In the case of peak loads thebrine return temperature would thenfall below -5 °C, which might resultin a switch-off of the heat pump.Thus, a deviation from the pipe dis-tance by more than 5 cm alwaysrequires a reduction of the surface-speciﬁc abstraction capacity.Example calculationHeat pump (data of manufacturer)- Heating capacity QH= 8.9 kW- el. power consumptionPel= 1.98 kW➔ Refrigerant capacity QO=6.92 kWHorizontal collector(data acc. to VDI 4640)- Annual usage period 1,800 h- Abstraction capacity qE= 25 W- Installation distance s = 0.8 m➔ Collector areaAmin= 277 m²➔ LK= 346 mDimensioning of horizontalcollector➔ 4 Heating circuit à 100 m➔ Actual installation distance= 0.69 mWhen dimensioning the collectorpipes low pressure losses are to beensured – important: increasedviscosity of the brine compared tothe medium water – since the pumpcapacity reduces the seasonal per-formance factor β of the heat pumpsystem.In case of monovalent dimensioningof the brine/water heat pump theheat sources must be dimensionedto meet the capacity requirement ofthe building QGand not that of theheat pump.The total heating capacity QWPincludes the capacity requirementof the building QGand for thedomestic hot water heating Qwwinconsideration of a blocking time Z.QWP= (QG+ QWW) · Z [W]If a model with lower heatingcapacity or smaller collector surfaceis used when selecting the heatpump, the operating hours of theheat pump increase. This means thecollector is under more strain or ahigher annual abstraction factorresults. To compensate the increaseof operating hours the collectorsurface has to be increased result-ing in a higher power consumption.Careful planning and dimensioningof horizontal collectors is indispen-sable. Undersizing is to be avoided,it leads to a decrease of the brinetemperatures and thus to poor sea-sonal performance factors.Undersizing can result in continu-ously decreasing heat source tem-peratures; in extreme cases theoperating limit of the heat pump isreached.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 29Laying and installationEarthwork represents a considera-ble cost factor of horizontal collec-tors. Basically it is possible toremove the ground soil over thefull area or to lay the pipe loopsin trenches or to use non-disruptivemethods. With the open excava-tion method a trench is excavatedwith a relatively small excavatorwith a shovel width that core-sponds to the pipe distance. Thena pipe loop is laid in this trench.When the second trench is exca-vated for another pipe loop theexcavated soil can be used tobackﬁll the ﬁrst trench. Duringbackﬁlling it must be ensured todensify the groud soil as best aspossible, because loose materialreduces the capillary effect whichresults in a low water contant andthus poorer thermal properties.Laying in trenches, however, is onlyuseful with pipe distance > 40 cm.With smaller distances there mostlyis no alternative to excavate over thefull area. The main disadvantagehere is that the double quantity ofground soil has to be moved sincethe strips of land between thetrenches are not available. In addi-tion free space is required to storethe complete excavated soil.Thetransport of the excavated soil to thefree space and back to the collectorﬁeld are additional work steps, whichwould not occur when laying thepipes in trenches. The non-disruptivelaying is the most efﬁcient variant,however the respective equipmentmust be provided.All pipe loops of the horizontalcollectors laid in the ground soilshould have the same length andcan be connected to a heat pumpthrough supply and return ﬂowmanifolds with collecting pipesaccording to the Tichelmann prin-ciple.When laying the pipes accordingto the Tichelmann principle therequired pipe length is divided inpipe loops switched in parallel forthe respective abstraction capaci-ty. Thus with respect to the pres-sure loss the ﬂow in the individualpipe loops, the pipe lengths andpipe diameters are to be consid-ered. The individual collector cir-cuits can be designed as pipeloops (picture Tichelmann installa-tion), spirals or double meanders.Laying system heating circuitas a spiralLaying system heating circuitas a double meanderTichelmann piping principlewith the heating circuitsdesigned as pipe loopsPossible installationvariants
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201230Bedding of the horizontal collector in accordance with VDI 4640According to VDI 4640 the pipeloops should not exceed a maxi-mum length of 100 m and their col-lecting line and distribution lineshould not exceed a length of 30 mto the heat pump due to pressurelosses. If it is not possible to laypipe loops of the same length ahydraulic compensation must beused for balancing valves to main-tain the same pressure loss in eachpipe register.Operational safetyPipe loops of the same length areto be laid with minimum slope tothe manifold to enable venting ofthe horizontal collector. All mani-folds and ﬁttings should be installedin rain protected chambers outsidethe building. Moreover the pipeloops should be equipped with ballvalves at the manifolds to be ableto shut them off. The collector pipesare to be connected to the mani-folds in a stress-free manner.Sealing of the collector surfaces isto be avoided. When installing aground energy collector below thefoundation slab of a building thefunctionality of the collector or thesurrounding ground soil is to beregarded as energy store. Long-term operation is only ensured withthe same heat extraction and heatinput level (heating and coolingfunction) over the year becauseregeneration of the soil by surﬁcialenergy input is excluded.Pipe connections assembled on theconstruction side that are notaccessible are to use maintenancefree connection methods e.g.Uponor Quick & Easy or electrofu-sion ﬁttings.According to DIN 4140-2 all collec-tor pipes in the area of the wallduct as well as all brine-carryingpipes installed in the house mustbe insulated (insulation resistant towater vapor diffusion) to avoidcondensing water.If possible, horizontal collectorsshould be laid in a minimum depthof 1.2 m up to a maximum depth of1.5 m to ensure optimal regenera-tion of the ground soil without therisk of naturally falling short of thefreezing point. In addition the heatpump system is ﬁlled with brine –usually a mixture of water and gly-col (heat transfer medium) to avoidfreezing of the collector and theevaporator.Heat transfer media for collectorpipes are always to be selected sothat in case of a leakage a ground-water and soil contamination isavoided or kept as low as possible.Non-toxic or biodegradable organicsustances regarding VDI 4640should be selected.Take care that ﬁlling and dischargeof the system is possible. To avoidoverfilling the heat pump systemhas to be equipped with a safetyvalve. The brine has to be mixedbefore ﬁlling it into the heat pumpsystem to ensure proper blendingand thus to avoid freezing at certainpoints. The glycol percentage usual-ly is between 25 – 30 %. Thus thepressure losses of the collectorpipes are by 1.5 -1.7 higher as ﬁlledwith pure water. This has to be con-sidered when dimensioning thepump. The pressure test has to becarried out in accordance withEN 805.ImportantThe antifreeze agent andthe water must be mixed ina sufﬁciently large contain-er before the horizontal col-lector is ﬁlled with the mix-ture!SupplylineTrench warning tape30 – 40 cm above pipe50 – 80 cm pipe distance(1.2 – 1.5 m with a diameter of 40 mm)Bedding:PE-XanosandbedrequiredPE100approx.30cmsandmin.70cm120-150cmMain fillingincl. road design
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 31Depending on the type of pipe usedthe pipe loops are to be laid in asand bed. Only when using UponorPE-Xa pipes embedding in sand isunnecessary due to their resistanceto slow and fast crack growth.The installation distance of horizon-tal collectors is to be selected sothat growing together of the iceradii that form around the collectorpipes is avoided. These distancesusually are between 0.5 m and0.8 m (1.2 – 1.5 m for 40 mm diam-eter).pools should be at least 0.7 m.Fixing of the pipe loops (height inthe ground and cleanrance) canbe done using pegs or by ﬁtting thepipes on reinforcement mesh.Legal regulationsCountry-speciﬁc approval of the responsible authorities may berequired for horizontal collectors. VDI 4640 and Wasserhaushalts-gesetz (Federal Water Act) (D), SIA 384/6 and BAFU-Vollzugs-richtlinie (CH), österreichische Wasserrechtsgesetz, Gewerbeord-nung und Bauordnung (Austrian Water Rights Act, IndustrialCode and Building Code are to be observed.The installation distance betweenhorizontal collectors and other sup-ply lines (gas, water, heat, power,etc.), buildings, circulation space,neighboring plots and swimmingPE-Xa pipe dimension[mm]Inner diameter[mm]Water volume[l/m]25 x 2.3 20.4 0.32732 x 2.9 26.2 0.53940 x 3.7 32.6 0.835Water volume per pipe dimension for horizontal collectors
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201232Schematic illustration of an energy cage systemEnergy CagesThe energy cage is a special designof the horizontal collectors. Energycages are used when deep drillingsor deep foundations are not possi-ble for reasons of water law condi-tions or for hydrological reasons,or when the available space is toosmall. The energy cage is an eco-nomically and energetically veryeffective alternative in the ﬁeld ofground energy.The Uponor Energy Cage is theideal solution for single-family ormulti-family houses as well as smallbusiness and industrial applica-tions.System/scope of applicationYour beneﬁtEconomically and energetical-ly effective for ground energyIdeal solution for single-familyand multi-family houses andsmall business and industrialapplicationsSmall landscape required whileat the same time good utiliza-tion of the soil volumeConstant heat extractionLow installation depth withouteffects on the groundwaterlevelNote:The combination of a groundenergy cage with the UponorEPG6 cooling station is anideal free-cooling solution.Application descriptionWhile operating the brine (water-glycol mixture) circulates throughthe energy cage and extractesheating from the Ground. In combi-nation with a heat pump the tem-perature level will be lift up to anuseable operation temperature.In the warm Summer months thecool ground soil temperature canbe used for passive cooling, alsoknown as free-cooling. During thisprocess usually only the brine cir-culation pump of the heat pump isrunning. Therefore the energy con-sumption during the cooling phaseis restricted to a minimum andclearly more cost-effective thanconventional cooling variants.The condition for the above, howev-er, is an radiant heating and coolingsystem. The targeted alternatingstress on the ground through heat-ing and cooling creates an energybalance in the subsurface and thusguarantees a long-serving energysource.The Uponor Energy Cage is designedfor use in a depth of 1-4 meters.The energy cage is installed close tothe surface and are positioned ina depth where seasonal temperatureﬂuctuations occur. Hence, theground soil temperature is 100 %
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 33affected by weather conditions.Seasonal ﬂuctuations are measura-ble up to a depth of approx. 20 m(regional differences); daily ﬂuctua-tions up to a depth of approx. 1 m.In addition a clear phase shiftbetween air temperature and groundsoil temperature can be seen. InNovember the highest ground soiltemperature prevails and in Maythe lowest, vice versa to the outertemperatures. This is caused by thefact that on the one hand theground soil is a poor heat conductorand on the other hand has a largeheat storage capacity.As a result the solar energy (solarradiation) that permeates theﬁrst meters of the earth’s surface inearly summer, is stored for severalmonths. The ground soil tempera-ture decreases slower than the airtemperature. At the beginning ofthe heating period the highest tem-peratures occur in the ground soil;the lowest prevail at the beginningof the cooling period.In the installation depths of theUponor Energy Cage a relativelyconstant temperature prevails overthe whole year ranging from approx.7 to 13 °C. The conical shape ofthe Uponor Energy Cage enablesutilization of a large ground soil vol-ume despite its relatively small sur-face area.Thus the large ground soil volumeand the steady heat extraction pre-vent untimely freezing of the directenvironment. In cases of extremeload it is only possible that ice formson the side of the energy cage.However, when reducing the loadthis ice formation will degenerate.Due to the fact that the extractiontemperatures are almost constantthis is an ideal energy source for theheat pump. Thus the efﬁciency ofthe heat pump is considerablyincreased. The preferred use is in acapacity range of up to 30 kW.Depthinsoil[m]Temperature (depth) [°C]On average the soil temperature increases by 1 °C approximately every 33 m.0 205 10 1520015105Temperature (earth’s surface) [°C]0 205 10 151. February 1. May 1. November 1. AugustUponor Energy Cage Installation depth: 1 to 4 mInstallation of the Uponor Energy CageDeﬁned collector pipe distance with the Uponor Energy Cage
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201234Due to the large-volume conicalshape of the Uponor Energy Cagean increased surface for the ab-sorption of ground energy is creat-ed and the content volume for theheat transfer medium, the brine, ismaximized. Thus the thermal energycan be extracted from the groundsoil more consistently.The so-called freezing solid isavoided since the heat extractiontakes place below the frost line indepths between 1 to 5 m. Thereby,In the table above a distinction ismade between sand, loam, silt andsandy clay which reﬂect the widespectrum of soils existing in nature.Sand in this context is loose soilconsisting of individual grains(> 50 mm). In this type of soil thecapillary effect is extremely lowand the groundwater permeabilityis high. Thus rainwater seepsquickly into deeper layers whichabove the groundwater results in alow volumetric water contentbelow 10 %.effects on the ecological micro-organisms in the soil are avoided.Due to this fact the surface abovethe installed Uponor Energy Cagecan be used as garden area withoutany effects. Overbuilding and seal-ing of the area should be avoided.The natural regeneration of thetouched ground is given by regularsolar radiation and moistening ofthe ground soil by rain and snow-melt. The low installation depthprevents a change in the water bal-Loam mainly consists of a mixtureof sand and silt, while silt is asoil with medium-ﬁne graininess(between 2 mm and 50 mm).These cohesive soils usually havevolumetric water contents between20 and 40 % and are thereforebetter suited for horizontal collec-tors than sand.In sandy clay the biggest fractionof which consists of very ﬁnegrains (< 2 mm) the capillary effectis even higher resulting in volu-metric water contents above 30 %.Application limitsance. The compact size of theUponor Energy Cage requires upto 60 per cent less space for thecomplete energy cage ﬁeld than acomparable horizontal collector.Szenarios such as uneven heavingof the ground soil by massive icering formation in case the dimen-sioning is too small, or formation ofan ice patch below the surfacewhich would cause rain and meltwater not to seep in, usually donot occur with energy cages.The exact physical properties varyfrom place to place which among oth-er things is caused by different pre-cipitation amounts.The table showsthe mean values of the physical prop-erties of the different soil types.Within Europe the climatic differ-ences are so big that it does notmake sense to lay horizontal collec-tor according to the same rules. Inwarm climes a higher surface-spe-ciﬁc abstraction capacity is possiblewithout causing damage of the sys-tem or the environment.Physical properties of the characteristic soil typesUnit Sand Loam Silt Sandy clayWater content % Vol. 9.3 28.2 38.1 36.4Heat conductivity W/mK 1.22 1.54 1.49 1.76Speciﬁc heat capacity J/kg K 805 1,229 1,345 1,324Density kg/m³ 1,512 1,816 1,821 1,820Source: VDI 4640
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 35When dimensioning an energy cagesystem the following aspects mustbe considered:The basis for the right dimensioningof the energy cage system is the cor-rect calculation of the heating loadand the concrete analysis of the soiltype and ground soil humidity.Selection of emitter systemFor an energy cage system as wellas for all other ground energy sys-tems the selection of the respec-tive emitter system and systemtemperature is extremely impor-tant. To ensure the highest possi-ble efﬁciency of the system itshould be selected to be as low aspossible.As a rule of thumb the followingapplies:An increase of the ﬂow temperatureDimensioning of Energy Cagesby 1 Kelvin means approx. 2.5 %more energy required. Recommend-ed ﬂow temperature for area heat-ing systems: max. 35°CBased on experience the followingreference values were determinedfor the dimensioning of the UponorEnergy Cages. They are used toassess the soil conditions. Soil class-es 1-4 (DIN 18300) are suitable forthe installation of an Uponor EnergyCage. From soil class 5 the manufac-turer must be contacted.Specific abstraction capacity (heating case) per Uponor Energy Cagewith 1800 h/a [W/basket]Reference value for the dimensioning of an Uponor Energy CageDry cohesionless soilCohesive, humid soilWaterlogged sand / gravel500 2000600 700 1000 1200 13001100800 1400 1500 1600 1700 1800 1900Specific abstraction capacity (heating case) per Uponor Energy Cage XLwith 1800 h/a [W/basket]Reference value for the dimensioning of an Uponor Energy Cage XL500 2000600 700 1000 1200 13001100800 1400 1500 1600 1700 1800 1900Dry cohesionless soilCohesive, humid soilWaterlogged sand / gravelThe beneﬁts of the UponorEnergy Cage are:No planning and cost-intensivedrilling workSimple building approvalprocedure (duty of disclosure,depending on the country)Due to the low installation depthuse even in water protectionareas possibleNo effects on the groundwaterNo risk of freezing solid, no effectson utilization as garden, no effectson capillary action of the soilQuick regeneration of theground soil by sun, rain andsnow meltPassive coolingLow space required, 50 – 60 %lower than with horizontal col-lectorsInstallation possible on plots ofland with difﬁcult access whereheavy drilling equipment cannotbe usedQuick installationMaintenance-free system
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201236If it should not be possible to clear-ly classify the soil on the construc-tion site, the ground soil should beanalyzed by a geologist.With operating modes > 1,800 h thenumber of Uponor Energy Cagesmust be adapted to the soil condi-tions.The required heat pump must beselected by the manufactureror heating engineer. He selects therespective heat pump model basedSinge-family houseCalculated heating capacity * 6 kWRefrigerant capacity 4 kW (according to HP manufacturer)Soil propertymax. abstraction capacity of an Uponor Ener-gy CageCohesive, humid soil1.2 kWRequired no. of energy cages 4Brine volume 336 lGround energy manifold size 2 outgoings* incl. hot water and blocking time of the utility company; 1,800 h operating periodMonoethylene glycol 29%Density kg/m³ 1,051cpkJ/(kg · m) 3,72Viscosity Pa · s 0.00313Mass ﬂow kg/s 0.36Max. no. of baskets in row 2Flow velocity m/s 0.32Pipe length PE-Xa 32 x 2.9 mm per Cageincl. connection line in m150Pipe length PE-Xa 32 x 2.9 mm by series con-nection of 2 Cages in m300Pressure loss of the energy cage series connec-tion incl. integrated connection line280 mbarPressure loss Uponor ground energy manifold, 2outgoings30 mbarTotal pressure loss incl. manifold 310 mbarThe calculation of the pressure lossrefers to the example given above.Here just the data for monothyleneglycol is used.on the heating load, the systemtemperatures, the application andthe operating time. This resultsin the cooling and heating capacity.The following example shows howto calculate the required number ofUponor Energy Cage:
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 37Entering trees, lines (water, tele-phone, wastewater, etc.) on the siteplan must be considered. Only thisway can potential problems be clari-ﬁed beforehand and the exactposition of the energy cage can bedeﬁned. Uponor Energy Cages canbe connected in series. The positionof the individual energy cages canbe deﬁned as requested.Take care that the energy cages arenot overbuilt with structures suchas garages, carports, cellars, swim-ming pools or streets. Otherwisenatural regeneration is no longerpossible.The following distances must bemaintained:The minimum distance to founda-tions, adjacent plots, trafﬁc areas,swimming pool and tap water andwastewater lines must be 1.5 to2 meters. The ideal distancesbetween the energy cage and thespace required can be found inthe table listing the technical data.The Uponor Energy Cage consistsof 150 m PE-Xa pipe of 32 x 2.9 mmdimension while the Uponor EnergyCage XL consists of 200 m pipe. Thepipe is ﬁxed on a framework offour foamed polyurethane brackets.The tapered conical increases thesurface to absorb the ground ener-gy and the volume for the energytransport medium. The PE-Xa pipemakes the Uponor Energy Cageresistant to slow and fast crackgrowth. Especially when reﬁlling theenergy cage excavation pit the Cagecan get into contact with sharp-edged ﬁlling material. When usingconventional materials, e.g. PE 100,Laying and installationthe pipes would be damaged. Thesoil would have to be exchanged fora humus/sand mixture. This is notrequired when using the UponorPE-Xa pipe.Uponor Energy CagePE-XaTechnical data Energy Cage Energy Cage XLPipe meter 150 m 200 mDiameter top (a) 2.4 m 2.4 mDiameter bottom (b) 1.4 m 1.4 mHeight (c) 2.0 m 2.7 mPipe distance 114 mm 114 mCage volume 6.1 m³ 8.1 m³Center distance Cage middle-middle (d) 6.0 m 7.0 mPure space required in case of layout inrow / Cage15 – 20 m² 20 – 25 m²Pure space required in case of parallel lay-out / Cage35 – 40 m² 35 – 40 m²Circuitry max. 2 in series directly individually at manifoldBrine volume 84 ltr. 108 ltr.Abstraction capacity (guaranteed with1800 full load hours per year)1.1 – 1.5 kW 1.6 – 2.0 kWPipe ﬁxing PU-foam strip with ﬁxing tapeIntegrated connection line for ﬂow andreturn ﬂow20 m 25 mdabc
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201238The Uponor Energy Cage should beconnected according to the Tichel-mann principle which says that withthe same pipe lengths and samecross-sections also identical ﬂowrates and ﬂow conditions prevail.It has to be ensured that the pipelengths do not differ by more than10 %.20 or 25 m ﬂow and return ﬂowconnecting lines are already integrat-ed in the Uponor Energy Cage. If inexceptional cases this should not besufﬁcient, the line can be extendedusing the Uponor Quick & Easy con-nection technology or electrofusionﬁttings.It must be ensured that the connec-tion lines have the same length toavoid different pressure conditions.If this cannot be avoided, an adjust-ment can be made using the ﬂow-meters at the Uponor ground energymanifolds.Uponor Energy Cages are usuallyinstalled in a depth of 1.4 meters.The installation time is approx. 1hour per kW heating capacity, i.e. fora singe-family home with 6 kWapprox. one working day should becalculated.The Uponor Energy Cages are deliv-ered to the construction site ontrucks. Due to their low weight theycan either be rolled to the construc-tion site after unloading or can bepositioned using an excavator.For the soil excavation the excavatorshould have a minimum weight of5-7.5 tons depending on the scopeof the project. If there is sufﬁcientspace, bigger excavators are prefera-ble – In the ideal case an excavatorwith a two-meter humus shovel.The energy cage excavation pit canbe reﬁlled with the soil excavatedbefore. It has to be ensured that theexcavation soil is washed in whenreﬁlling the energy cage excavationpit.To avoid settlement compactingequipment can be used after reﬁll-ing. Otherwise settings might occurduring the ﬁrst two years.Installation of the energy cage
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 39The Uponor Energy Cage should beinstalled following the steps below:1. Excavation work2. Fitting of the Uponor EnergyCage and reﬁlling of excavationpit3. Connection to manifold4. Pressure test5. Filling the system6. Acceptance and documentationof energy cage systemWith a suitable excavator a squareexcavation of approx. 2.5 x 2.5 m ismade for the ﬁrst Uponor EnergyCage and Energy Cage XL to be ﬁt-ted. The excavation depth dependsPositioning the connection linesDetaching the connection lines Fixing the return ﬂow lineFixing the ﬂow line Excavation of the installation pit Positioning the energy cageWashing in the ﬁlling material Reﬁlling of the Uponor Energy Cage PE-Xa Installed and compacted energy cageon the regional frost line. In mostregions this is 0.7 – 1.2 m below theearth’s surface. Hense an excava-tion depth between 3.2 – 3.7 m canbe assumed. Then a connectiontrench with a depth of 1.2 m is cutfrom the ﬁrst excavation hole tothe manifold.Before the energy cage can be low-ered into the excavation pit someadditional preparatory steps shouldbe taken.The connection line integrated inthe energy cage must be pulled outof the inside and ﬁxed to the pipeturns using cable ties. With this stepthe “twist“ is removed from theconnection line which facilitateslaying of the pipe in the connectiontrench later.The following pictures illustrate thisagain.After the excavation work the ener-gy cage is lowered into the excva-tion pit using a suitable machine(excavator) and reﬁlled with the soilexcavated before. It is importantto wash it in with sufﬁcient water.The other energy cages are posi-tioned accordingly.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201240PE-Xa pipe dimension[mm]Inner diameter[mm]Water volume[l/m]32 x 2.9 26.2 0.539It has to be ensured that theplanned minimum distances of theenergy cages among each otherare maintained. Then connectiontrenches are cut between twoeach of the individual energy cagesof the Cage ﬁeld aligned with thetop edge of the energy cage. Thenthese two energy cages are con-nected in series. The Uponor EnergyCage XL must be connected indivi-dually.Depending on the installation vari-ant now the individual connectionlines already integrated in the ener-gy cage, the energy cages connect-ed in series or the extened connec-tion lines are connected to theUponor ground energy manifoldand mounted on the manifold bymeans of compression ﬁttings.Depending on the volume ﬂow ofthe energy cage system the connec-tion lines can have different dimen-sions. This has to be calculted inadvance. The house duct should besealed watertight to pressure. Alter-natively the Uponor manifold shaftcan be used.The pressure test according toEN 805 has to be carried out oneach pipe run.The energy cage system must beﬁlled with an anti-freeze solutionaccording to VDI 4640 for up tominimum -15 °C. When usingUponor anti-freeze solutions thiscorresponds to a mixing ratio of 3:1.The brine quantity required for theenergy cage can be found in thetechnical data. The anti-freeze solu-tion and the water must be mixedin a sufﬁciently large container,before the Uponor Energy Cage isﬁlled with the mixture!After completion of the UponorEnergy Cage ﬁeld it is recommend-ed to enter the actual position ofthe Cage in the site map and tomark it with pipe run numbers. Thisdocumentation is useful for assign-ing the pipes to the manifold andfor evidence for the authorities. Theperson installing the system isresponsible for compliance with allvalid standards and regulations.An acceptance procedure for thesystem has to take place.Example for the right mixingratio:ImportantThe anti-freeze solution andthe water must be mixed ina sufﬁciently large containerbefore the Uponor EnergyCage is ﬁlled with the mixture!Legal regulationsThe country-speciﬁc regulations such as VDI 4640 and Wasser-haushaltsgesetz (Federal Water Act) (D), SIA D-0190, SIA S 0179and BAFU-Vollzugsrichtlinie (CH), österreichische Wasserrechts-gesetz, Gewerbeordnung und Bauordnung (Austrian WaterRights Act, Industrial Code and Building Code are to be observedfor all energy cage systems.Water volume per pipe dimensionBrine volumeUponorEnergyCageUponorEnergyCageXLTotal brinevolume84 l 108 lMixing ratio 3:1 3:1>Anti-freezesolution21 l 27 l>Water 64 l 81 l
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 41Energy PilesSystem/scope of applicationApplication descriptionAn energy pile has to fulﬁl twofunctions:The main function is the load trans-fer into the ground; the secondaryfunction is the use as ground ener-gy transfer medium. By using thefoundation pile as energy pile itsload-bearing capacity must not beaffected.Application limitsA reduction of the load-bearingcapacity of the pile (formation offrost, reduction of cross-section dueto heat exchanger pipes) must beexcluded in any case by temperaturelimitation and static tests. Energypile systems are often ground loadsystems. Peak loads must be cov-ered by additional ground energysystems, if necessary.Single-family houses with deepfoundations usually can be providedmonovalently with Energy Piles dueto their excellent insulation – how-ever, this is a rare application.The building statics determine thelayout and number of foundationpiles. A layout of foundation pilesaccording to energetic aspects isoften not economical (exception:e.g. low-cost pre-fabricated drivenpiles, that are partly also used as“lost piles”).Schematic illustration of an energy pile systemBeneﬁtsVery low additional invest-ment costs in case ofplanned pile foundationsBase-loadableCan be used with all deepfoundationsIdeal solution for residentialand non-residential applica-tionsDepthinsoil[m]Temperature (depth) [°C]On average the soil temperature increases by 1 °C approximately every 33 m.0 205 10 1520015105Temperature (earth’s surface) [°C]0 205 10 151. February 1. May 1. November 1. AugustUponor energy pile Installation depth: ca. 10 - 30 m
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201242Filling pipe for concreting Supervision of the pile assemblyAn energy pile system should beoperated as alternating storagesystematically changing heatingand cooling operation. Thus anoptimal speciﬁc abstraction capaci-ty is achieved both for heating andcooling generation. The tempera-ture balance of the energy pile sys-Concreting procedure of the in-situ pilesInstalling the reinforcing cagestem can be designed in a sustaina-bly stable manner. With an almosteven heat balance over the yearsthe mutual thermal interferene ofadjacent Energy Piles is minimized.From experience with medium-sized and big energy pile systemsthe basic load operation is the mosteconomical one. For this an optimumratio of capacity and work is to beplanned and deﬁned during dimen-sioning. Mainly the heating andcooling work performed determinesthe efﬁciency of the energy pilesystem.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 43Foundation pilesWhen it comes to foundation pilesa distinction is made between thetype of assembly and the installa-tion.Type of assemblyPre-fabricated pilePile is pre-fabricated completelyor in parts before installing it intothe ground.Massive concrete pilesHollow spun concrete pilesSteel pipesIn-situ concrete pilePile is assembled on site in theground by ﬁlling a cylindrical voidwith concrete.Type of installationRam and press pile.Pile is rammed into the ground orpressed into the ground under stat-ic pressure.Bored pile.Pile is installed in a borehole. Theboreholes can be generated usingdifferent drilling methods.Drilling methodsKelly-method.With the Kelly method uncased,partly cased, fully cased orslurry-supported bored pilesare produced. The drilling toolis ﬁxed on a telescopic Kellybar. When using a full encasingthe bore pipes are drilled intothe ground until they reach therequired depth and drilling iscontinued until they reach theﬁnal depth.Kelly-method with pile baseexpansion.Pile base expansions are basedon the principle of a circularsymmetric extension of the dia-meter at the bottom of the bore-hole. The outer load capacity ofthe pile is increased by enlargingthe endbearing area of the pilein the bearing soil. The extensionmeasure is deﬁned in considera-tion of the existing soil and thegeometric limiting criteria ac-cording to statical requirements.Another possibility to increasethe load-bearing capacity isshaft grouting. With this methodthe skin friction of the bore pileis increased by ﬁlling it up withcement suspension.SOB-methodThis pile drilling method is anauger drilling procedure whichenables a high drilling meteragein ﬁrm ground. With this methoda continuous ﬂight auger is usedas a drilling tool. After reachingthe ﬁnal depth of the boreholethe inner tube of the hollow stemauger is fed with concrete frombottom to top.DKS-method.The dual rotary head systemis the combination of the SOBmethod with continuous drillauger and the Kelly methodwith encasing. The result is anencased boring generated with acontinuous ﬂight auger.VDW-method.The against-the-wall system wasdeveloped out of the demandto be able to erect new build-ings directly in front of existingbuildings in cities. The produc-tion principle corresponds to thatof the DKS method, but smallerdiameters are used.Assembly of a bore pile Prefabricated concrete bored pile
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201244Foundation pile typesBored piles (hollow-spun piles)Bored piles (hollow-spun piles) areround piles made of concretethat are transferred into the groundthrough different drilling proce-dures. They divert structural loadsinto deeper, solid soils, stringedtogether form a retaining wall forexcavation pits or terraces, re-move obstacles in the soil or blockgroundwater below the surface.Corresponding to the use length,diameter, material, design andlayout of the individual piles canbe varied.Special type of bored piles aremicro-piles. These are foundationelements with a diameter of up to300 mm, by means of which loadsare trasnferred into deeper solidground layers through skin friction.The special feature of the micro-pileis that with a small diameter a highload bearing can be achieved bytargeted pressure grouting technol-ogies.Due to a multitude of device vari-ants highly productive proceduresfor the production of small diameterbored piles also in conﬁned areasare possible.Buildings that were damaged byuneven settlements can be stabi-lized by and/or raised by pre-stressed micro-piles. Adapted to therespective soil conditions micro-piles can be assembled with variousdrilling methods. The bored piles areprovided with continuous reinforce-ment that absorbs tensile loads,pressure or alternating loads.The load transfer to the surroundingground is achieved by ﬁlling orgrouting the borehole with cementmortar (with or without supportgrain). The pile is post grouted inorder to increase the skin friction /load transfer.Hollow-spun concrete ram pilesThe Hollow-spun concrete ram pilesis an extremely economical andtechnically sound alternative to con-ventional foundation systems. Theductile ram pile is a quick, ﬂexibleand simple foundation system, inwhich ductile cast iron pipes –depending on the length requiredwith pipe segement, that areplugged into one another usingsleeves – are rammed into theground to transfer loads.Depending on the soil propertiesthe pile is constructed as end-bear-ing pile or as pressure-grouted pile.Depending on the load to be trans-ferred different pipe diameters withthe respective wall thicknesses areavailable for pile construction. Dueto the use of lightweight and agilehydraulic excavators also minorbuilding activties in conﬁned spacecan be carried out. The piles areinstalled on the construction site bymeans of a double-acting hydraulichammer almost without vibration.Pressed massive concrete pileThe pressed massive concrete pileis built up of sections whichare pressed into the ground by ahydraulic system. An existing build-ing or a ballast arrangement pro-vides the reaction necessary for this.The pile is built up of reinforcedconcrete sections placed on top ofeach other. Soil can be excavatedfrom the pile through the hollowpile core so that the pile reaches therequired depth without a large reac-tion being required. When the pile isat the correct depth, an enlargedbase is made by compacting metalcontainers with a dry mortar mixtureunder the pile.The pile core is ﬁlledwith concrete. This working methodis vibration free.Since light, dismountable machinesare used, this system is extremelywell suited for working under difﬁ-cult conditions and in very conﬁnedworking spaces.The pressed massive concrete pile ismainly used for underpinning work.The reaction required in this case isusually provided by the buildingitself by means of a new concreteﬂoor cast on site. Anchors are con-creted into this concrete ﬂoor andholes are left open through whichthe piles are pressed. The pictureat the top of this page shows howthis method works. By using thistechnique it is possible to ﬁx thepiles onto the ﬂoor at a preload.The minimum working height is0.8 m. As a result it is possible toforce a jacked reinforced concretepile under an existing foundation.This existing foundation is thenused as the counterweight for jack-ing the pile.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 45Pre-fabricated concrete pilesPre-fabricated concrete piles aremanufactured with circular cross-section or a square cross-sectionwithout void. They transfer highbuilding loads to deeper solidground through skin friction andload transfer and are providedwith continuous reinforcement.Pre-fabricated ram concrete pileThe pre-fabricated ram concretepile is a very economical and tech-nically sound alternative to conven-tional foundation systems as well.The pre-fabricated full-wall pilesare installed on the constructionsite almost without vibration usinga double-acting hydraulic hammer.Depending on the subsurface it ispossible that the originally plannedpositioning depth is not reachedand the pile has to be cut to length.In case of activation with pipe loopsthe removal of surplus concretebears the risk that the heat exchang-er pipes are damaged.In-situ pilesWith large-diameter bored pilesthe soil is not pushes aside but asteel pipe with an opening on thebottom is drilled into the ground.The soil is then removed and aninner steel reinforcement is insert-ed and ﬁlled with in-situ concrete.Then the steel pipe is pulled outagain. This type of in-situ pile isused for statically sophisticatedfoundations such as high-risebuildings.Slotted wallsSlotted walls are walls assembledin the ground from so-called in-situconcrete that can reach in greatdepths. The walls – thicknessaccording to statical requirementsand equipmed used – are manu-factured with low-noise and low-vibration methods.Slotted walls show minim deforma-tions, and are therefore mainly usedas retaining walls in inncer cityfoundations. Due to their relativelyhigh watertightness they are alsoused at outer wall of the building tobe constructed. In special casesindividual slotted wall elelments arealso used for deep foundations.Cut-off walls seal dams and retainlandﬁll sites, take storages or otherindustrial plants that may jeopard-ize the groundwater.By means of special grippers or mill-ing cutters the ground is openedup into the depth forming slots,whereupon the slot is continuouslysecured by means of a slurry ﬂuid.In-situ concrete slotted wall.When the required wall depth isreached the slurry ﬂuid usuallyis replaced by reinforced concreteso that statically effective andgroundwater retaining walls canbe assembled.Single-phase sealing walls.Single-phase sealing walls areslotted walls made of a self-hardening suspension which areconstructed in a slot excavatedin the ground. The self-hard-ening suspension is at the sametime used as support suspen-sion. Sealing elements such asdiaphragms or sheet pilings canbe installed additionally.Inserting the steel reinforcing cage in theborehole
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201246HP CPExcavation of a pit and preparation ofa pile driving schemeRam and coupling the hollow-spunpilesCutting off the projecting hollow-spun piles, checking the void andmeasuring of the effective voidlength using the tape measureFitting of the double U-collector andsubsequent filling o the voidLaying and mounting of the horizontalconnection lines incl. connection tothe manifold connection group.Pressure test of the complete systemconcreting of the foundation slab.Completion of the shell and mountingof the circulation pump (CP) and heatpump (HP)Bored piles (hollow spun piles)Hollow-spun concrete ram piles andpress piles are only provided withcollector pipes after they have beendriven into the ground. This is also abig advantage of the hollow-spunconcrete piles since the collectorpipes can be adapted to the actualinsertion dept and the risk ofdamage of the collector pipes canbe minimized by inspecting the pilevoid in advance.Similar to borehole collectors twopipe loops are lowered into theground and ﬁlled up with backﬁllmaterial. In case of narrow bendingradii of the pipe loops it is recom-mended to use electrofusionU-bends or alternatively boreholecollectors can be inserted directly.During backﬁlling it is to be ensuredthat the backﬁll material showshigh heat conductivity, good con-tact to the materials under differentActivation of foundation pilesenvironmental conditions and that itcan be fed in without creating voids.The supply and return ﬂow of arespective energy pile can be bun-dled through Y-pieces or T-piecesand combined in groups with otherpiles.Installation ofthermally activatedhollow-spun piles
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/2012 47Pre-fabricated ram concretepilesPre-fabricated ram concrete pilesare already equipped with therespective collector pipes at thefactory. To do so, the collector pipeis ﬁxed on the inside of the rein-forcing cage and the pile is con-structed by concreting. The numberof pipe loops is adapted to the pileform and the pile diameter.A recess for the connection lines isto be provided at the bottom of thepile. The pipe ends are led out ofthe pile so that they protrude afterinstallation. During installation thedirection of the projecting pipeends should be selected so that theInstallation ofthermally activatedpre-fabricated con-crete pilesExcavation of a pit Preparation of a pile driving scheme Driving the pre-fabricated concretepilesRemoval of the protective coatingand installing of the 90° bracketsLaying and mounting of the horizontalconnection lines incl. connection tothe manifold connection group.Pressure test of the complete systemconcreting of the foundation slab.Completion of the shell and mountingof the circulation pump (CP) and heatpump (HP)HP CPconnection line does not have to beled around the pile.Depending on the subsurface it ispossible that the originally plannedpositioning depth is not reachedand the pile has to be cut to length.In case of activation with pipe loopsthe removal of surplus concretebears the risk that the heatexchanger pipes are damaged.The beneﬁt of using pre-fabricatedconcrete piles is that the ﬁtting andpressure tests are carried out in thefactory and damages of the heatexchanger pipes are excluded dueto concreting of the pile on theconstruction site.
UPONOR GROUND ENERGY TECHNICAL INFORMATION 05/201248In-situ concrete pilesWith piles that are manufacturedwith the in-situ concrete method thereinforcing cage is provided with thecollector pipes before inserting it intothe prepared borehole. The collectorpipes are usually mounted on theinside of the reinforcement cage toavoid damage of the pipes wheninserting the reinforcing cage into theborehole.. When doing this the collec-tor pipes are ﬁxed vertically endlessin a spiral at the reinforcing cage wallor crosswise at the pile foot or inindividual pipe loops with redirection(Omega bow) at the reinforcing cagewall or crosswise at the pile foot inthe reinforcing cage using cable ties.Inserting the PE-Xa pipe loops Cutting the inserted pipe loops to length Fixing the pipe loopsStorage of ﬁtted reinforced cages Connection lines made of Uponor ground energy PE-Xa pipesPipe loops ﬁtted inthe reinforced crates