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Free cooling guide 02 2013_46512

  1. 1. 02 | 2013Free cooling guideCOOLI N G I N TEGRATI ON I N LOW-ENERGY HOU SES
  2. 2. Table of contents1. Introduction to the concept of free cooling ...3The need for cooling in low-energy houses.............4Comfort and energy efficiency – the best fitfor low-energy houses ............................................4Investing for the future – the design of alow-energy house ...................................................52. Cooling loads in residential buildings .............6Factors influencing the sensible cooling load..........6Factors influencing the latent cooling load .............7The effect of shading..............................................7Room variation .......................................................8Duration of the cooling load ..................................8Required cooling capacity.......................................93. The ISO 7730 guidelines.................................10Optimal temperature conditions............................10Draught rate .........................................................11Radiant asymmetry ...............................................11Surface temperatures............................................12Vertical air temperature difference........................124. Capacity and limitations of radiantemitter systems ..............................................13Heat flux density...................................................13Thermal transfer coefficient..................................13Dew point limitations............................................13Theoretical capacities of embeddedradiant cooling......................................................145. Ground heat exchangers.................................15Ground conditions ................................................15Ground heat exchangers .......................................16Ground temperature profile...................................17Primary supply temperatures.................................17Dimensioning of ground heat exchangersfor free cooling .....................................................176. Free cooling in combination withdifferent heat sources ....................................197. Choosing and dimensioning the radiantemitter system................................................20Capacity of different radiant emitter systems........20Radiant floor constructions and capacity ..............22Radiant ceiling constructions and capacity ...........24Capacity diagrams.................................................24Regulation and control..........................................26The self-regulating effect in underfloor heating ..27Functional description of Uponor ControlSystem .................................................................27Component overview ............................................298. Uponor Pump and exchanger group (EPG6)for ground sourced free cooling.....................29Dimensions ...........................................................30Pump diagram.......................................................30Control principle ...................................................31Installation examples.............................................33Operation of Uponor Climate Controller C-46.......36Operation mode of Uponor ClimateController C-46 .....................................................36Dew point management parameters andsettings.................................................................37Heating and cooling change-over:external signal.......................................................38Heating and cooling change-over:Uponor Climate Controller C-46............................382 UPONOR · FREE COOLING G UIDE
  3. 3. 1. Introduction to the concept of free coolingFree cooling is a term generally used when low externaltemperatures are used for cooling purposes in buildings.This guide presents a free cooling concept based ona ground coupled heat exchanger combined with aradiant heating and cooling system. A ground coupledheat exchanger can for example be horizontal collectors,vertical boreholes or energy cages. A radiant systemmeans that the floors, ceilings or walls have embeddedpipes in which water is circulated for heating andcooling of the building. Under floor heating and coolingis the most well know example of a radiant system.A radiant system combined with a ground coupled heatexchanger is highly energy efficient and has severaladvantages. In the summer period, the ground coupledheat exchanger provides cooling temperatures that arelower compared to the outside air. The radiant systemoperates with large surfaces, which means it can utilizethe temperatures from the ground directly for coolingpurposes. The result is that free cooling can be providedwith only cost being the electricity required for runningthe circulation pumps in the brine and water systems.No heat pump is required.In the heating season the system is operated using aheat pump. As the ground temperature during winteris higher compared to the outside air temperature,the result is improved heat pump efficiency (COP)compared to an air based heat pump. In addition, theradiant emitter a system (under floor heating) operatesat moderate water temperatures in large surfaces whichfurther improves the heat pump COP.3UPO NO R · FREE COOLING GUIDE
  4. 4. The need for cooling in low-energy housesToday, there is a high focus on saving energy andutilising renewable energy sources in buildings.The energy demand for space heating is reduced byincreased insulation and tightness of buildings.However, increased insulation and tightness alsoincrease the cooling demand. The building becomesmore sensitive to solar radiation through windows andbecomes less able to remove heat in the summer. Moreextreme weather conditions further contributes to thecooling needs and together with an even more increasedconsumer awareness of having the right indoor climate,the need for cooling also in residential buildings willbecome a requirement. Optimal architectural designand shading will help to reduce the cooling need, butsimulations and practical experience show that suchmeasures alone will not eliminate the cooling need.Space cooling is needed, not only in the summer, butalso in prolonged periods during spring and autumnwhen the low angel of the sun gives high solar radiationthrough windows. In order to meet the energy framerequirements of the building regulations, space coolingcan be provided by utilising renewable energy sourcessuch as ground heat exchangers for cooling purposes inconjunction with a radiant system with embedded pipesin the floor, wall or ceiling.Cooling needs will differ between rooms and are highlyinfluenced by direct solar radiation. Rooms with largerwindow areas and facing the south will generally havehigher cooling requirements. In periods with highcooling loads, active cooling is normally required duringboth day and night time.Comfort and energy efficiency– the best fit for low-energyhousesUsing shading will help to reduce the cooling demand.However, this forces occupants to actively pull down theshades e.g. when leaving the house. Also, shading willblock daylight which increases electricity consumptionon artificial light, and shading will block the view whichmay not be in the interest of the home occupant.In fact many architects state that energy efficiencyand comfort may conflict when defining comfort in abroader sense, such as the freedom to design windowsizes, spaciousness with increased ceiling height,daylight requirements and the occupant’s tendency toutilise open doors and windows. All such requirementsput increased demands on the HVAC applications.Ground heat exchangers combined with radiant systemsis the only “all-in-one” solution, with the ability toprovide both heating and cooling. Such systems aremore cost efficient and simpler to install than havingto deal with a separate heating and cooling systems.Furthermore, radiant systems are able to heat at alow supply temperature and cool at a high supplytemperature. This fits perfectly to the typical operatingtemperatures of a ground coupled heat exchanger.Furthermore, the connected heat pump will be ableto run more efficiently and thereby consume lesselectricity. In addition, a radiant system provides nodraught problems and provides an optimal temperaturedistribution inside a room. Last but not least, radiantsystems provide complete freedom in terms of interiordesign, as no physical space is occupied inside the room.Even more important when looking at the lifetime andproperty value of a house, such systems have very lowmaintenance need and a lifetime that almost followsthe lifetime of the building itself. In today’s uncertainenvironment of future energy prices, free cooling andground coupled heat pumps provides a high stabilityon the future energy costs of the building in question.It will most certainly meet today’s and future buildingregulations even in a scenario where future propertytaxation would be linked to energy efficiency. Hence, itis an investment that helps to maintain and differentiatethe future property value.4 UPONOR · FREE COOLING G UIDE
  5. 5. Investing for the future – thedesign of a low-energy houseA radiant system, e.g. underfloor heating and cooling,coupled to a ground source heat pump, providesoptimal comfort with high energy efficiency bothsummer and winter. In addition, due to the increasedtightness requirements in low-energy houses, aventilation system is necessary to maintain anacceptable indoor air quality. In order to keep theventilation system energy efficient, it should be coupledto a heat recovery ventilation (HRV) unit to minimiseheat losses through the air exchange.Energy sources for coolingThere are several alternative HVAC applications availablefor cooling purposes. A district heating connection is anenergy efficient option for space heating, but cannotbe used for cooling purposes. Alternative means ofcooling could be an air-to-water heat pump, but no“free cooling” can be extracted from such a system,hence cooling can only be provided with the heatpump running causing a higher electricity consumption.Purely air-based systems like split units can also act asa cooling system but as can be seen from the picturebelow, the efficiency is considerably lower than forwater-based cooling systems.European seasonal energy efficiency ratio (ESEER) for different coolingsystems. ESEER is defined by the Eurovent Certification Company andcalculated by combining full and part load operating conditions.Correlation between average property m2prices and energy classThe figure above shows the correlation betweenproperty prices and the energy efficiency level of theproperty in Denmark. Properties with energy class A orB are on average 6% more expensive than energy classC and 17% more expensive than energy class D.DKK/m2Energy class0510152025Air to airheat pumpAir to waterheat pumpBrine to waterheat pumpFreecooling5UPO NO R · FREE COOLING GUIDE
  6. 6. 2. Cooling loads in residential buildingsThe design cooling load (or heat gain) is the amountof energy to be removed from a house by theHVAC equipment, to maintain the house at indoordesign temperature when worst case outdoor designtemperature is being experienced. As can be seenfrom the figure above, heat gains can come fromexternal sources, e.g. solar radiation and infiltrationand from internal sources, e.g. occupants and electricalequipment.Two important factors when calculating the cooling loadof a house are:• sensible cooling load• latent cooling loadThe sensible cooling load refers to the air temperatureof the building, and the latent cooling load refers to thehumidity in the building.Factors influencing the sensiblecooling load• Windows or doors• Direct and indirect sunshine through windows,skylights or glass doors heating up the room• Exterior walls• Partitions (that separate spaces of differenttemperatures)• Ceilings under an attic• Roofs• Floors over an open crawl space• Air infiltration through cracks in the building, doors,and windows• People in the building• Equipment and appliances operated in the summer• Lights6 UPONOR · FREE COOLING G UIDE
  7. 7. The effect of shadingTo reduce the cooling load from solar gains, the mostefficient and sustainable way is to use passive measures.From an architectural point of view, shading can becreated by building components and by using blinds.Depending on the type of blinds used, the solar gaincan typically be reduced with up to 85% with externalshading. The figures below show a building simulationexample conducted on a low-energy single familyhouse, where using different shading factors have beenapplied.Without shading; cooling loads up to 60 W/m2.Shading factor 50%; cooling loads up to 40 W/m2.Shading factor 85%; cooling loads up to 25 W/m2.As can be seen from the figures above, even with themost efficient shading factor, the cooling load stillamounts to 25 W/m2.ExternalheatgainInternalheatgainTransmission (Sensible)Solar Radiation (Sensible)AirVentilation(Sensible)(Latent)(Sensible)(Latent)(Sensible)(Sensible)(Latent)LightingEquipmentPeopleCONDITIONEDSPACETotalsensibleTotallatentCoolingLoad2%5%3%10%13%15%52%Heat from air flowsHeat from occupants(incl. latent)Heat from equipmentHeat from walls andfloors (structure)Heat from lightingHeat from daylight(direct solar)Heat from windows(including absorbed solar)and openingsFactors influencing the latentcooling loadMoisture is introduced into a room through:• People• Equipment and appliances• Air infiltration through cracks in the building, doors,and windowsInternal gains in residential buildings are limited to thepeople normally occupying the space and householdequipment. In national building regulations, the loadfor internal gains in ordinary residential buildings isoften mentioned (3-5 W/m2). In residential buildings,the cooling load primarily comes from external heatgains, and mostly from solar gains through windowsand doors, transmission through wall and roof, andinfiltration through the building envelope/ventilation.The figure below shows that about 2/3 of the coolingload comes from the solar radiation.7UPO NO R · FREE COOLING GUIDE
  8. 8. 373635343332313029282726252423222120195001000150020002500300035004000450050005500600065007000750080008500Temperature[°C]Time [h]No window opening, no HRV by-passOpen windows, no HRV by-passOpen windows, with HRV by-passUFH, no opening windowRoom variationThere is a big variation in the cooling load from roomto room, caused by the architectural design of thebuilding. Large window areas facing the south and westare needed for daylight requirements and winter heatgains, but they also incudes high summer cooling loads.As a result of large south facing window areas, thecooling demand in south facing rooms are higher thanin the north facing rooms. In addition, the desiredtemperature levels of each room may differ rangingfrom the highest temperature requirements in thebathroom, to the lowest temperature requirements inthe bedroom.Duration of the cooling loadThe figures below show the duration of over-tempera-ture with different shading and ventilation strategies.The data originates from a full year building simulationof a low-energy single family house in NorthernEuropean climatic conditions (Denmark).Without shading; over-temperature up to 2 300 hours per year.373635343332313029282726252423222120195001000150020002500300035004000450050005500600065007000750080008500Temperature[°C]Time [h]No window opening, no HRV by-passOpen windows, no HRV by-passOpen windows, with HRV by-passUFH, no opening window373635343332313029282726252423222120195001000150020002500300035004000450050005500600065007000750080008500Temperature[°C]Time [h]No window opening, no HRV by-passOpen windows, no HRV by-passOpen windows, with HRV by-passUFH, no opening windowShading factor 50%; over-temperature up to 1 100 hours per year. Shading factor 85%; over-temperature up to 800 hours per year.The simulations show that without active coolingthere will be a significant amount of time with over-temperature (assuming that the maximum temperatureallowed is 26 °C). All the cases also show thatwith radiant floor cooling, it is possible to keep thetemperature below 26 °C all year round. Nationalbuilding regulations across Europe have already startedto implement maximum duration periods of over-temperature. In Denmark, the requirement in the 2015standard is that a temperature above 26 °C is onlyallowed for maximum 100 h during the year and above27 °C for maximum 25 h during the year.8 UPONOR · FREE COOLING G UIDE
  9. 9. 5000450040003500300025002000150010005000Capacity[W]JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberCoolingHeating5000450040003500300025002000150010005000Capacity[W]JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberCoolingHeating5000450040003500300025002000150010005000Capacity[W]JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberCoolingHeatingRequired cooling capacityBased on the peak load calculations of the building, theheating and cooling system can be designed. The HVACsystem should be designed to cover the worst case(peak load). The figures below show an example of thevariation of the needed capacity to cover the heatingand cooling loads.Required heating and cooling capacityLow energy building, shading in-between windows.Window opening and HRV by-pass are used during cooling seasonLow energy building, external shading.Window opening and HRV by-pass are used during cooling seasonAs can be seen, the cooling capacity peaks are actuallyhigher (up to 4 kW), than the heating capacity peaks(up to 3.5 kW) under any shading conditions (excludingdomestic hot water). Although, the heating periodstill remain longer than the total cooling period, it isinteresting to note that the cooling period extends intoearly spring and late autumn.Low energy building, no shading.Window opening and HRV by-pass are used during cooling season9UPO NO R · FREE COOLING GUIDE
  10. 10. In order to provide thermal comfort, it is necessaryto take into account local thermal discomfort causedby temperature deviations, draught, vertical airtemperature difference, radiant temperature asymmetry,and floor surface temperatures. These factors caninfluence on the required capacity of the HVAC system.Optimal temperature conditionsEN ISO 7730 is an international standard that can beused as a guideline to meet an acceptable indoor andthermal environment. These are typically measured interms of predicted percentage of dissatisfied (PPD)and predicted mean vote (PMV). PMV/PPD basicallypredicts the percentage of a large group of peoplethat are likely to feel “too warm” or “too cold” (theEN ISO 7730 is not replacing national standards andrequirements, which always must be followed).PMV and PPDThe PMV is an index that predicts the mean value ofthe votes of a large group pf persons on a seven-pointthermal sensation scale (see table below), based on theheat balance of the human body. Thermal balance isobtained when the internal heat production in the bodyis equal to the loss of heat to the environment.PMV Predicted mean votePPD Predicted percentage dissatisfied [%]+3 Hot+2 Warm+1 Slightly warm0 Neutral-1 Slightly cold-2 Cool-3 ColdSeven-point thermal sensation scaleThe PPD predics the number of thermally dissatisfiedpersons among a large group of people. The rest ofthe group will feel thermally neutral, slightly warm orslightly cool.The table below shows the desired operative tempera-ture range during summer and winter, taking into con-sideration normal clothing and activity level in order toachieve different comfort classes.ClassComfort requirements Temperature rangePPD[%]PMV[/]Winter1.0 clo1.2 met[°C]Summer0.5 clo1.2 met[°C]A < 6 - 0.2 < PMV < + 0.2 21-23 23.5-25.5B < 10 - 0.5 < PMV < + 0.5 20-24 23.0-26.0C < 15 - 0.7 < PMV < + 0.7 19-25 22.0-27.0ISO 7730 basically recommends a target temperatureof 22 °C in the winter, and 24.5 °C in the summer. Thehigher the deviation around these target temperatures,the higher the percentage of dissatisfied. The reasonfor the different target temperatures is because that thetwo seasons apply different clothing conditions as canbe seen in below figure:Operative temperature for winter and summer clothingDissatisfied[%]PPDPMVOperative temperature [°C]Basic clothinginsulation: 0.5PredictedPercentageofDissatisfied[%]Basic clothinginsulation: 1.0Metabolic rate:1.23. The ISO 7730 guidelines10 UPONOR · FREE COOLING G UIDE
  11. 11. 1802462080 5 10 20 30 3525150 9 18 36 54 634527[°C][°F]604010Dissatisfied[%]Radiant temperature asymmetry [°C]Warm ceiling Cool wallCool ceiling Warm wallRadiant asymmetryWhen designing a radiant ceiling or wall system, makesure to stay within the limits of radiant asymmetry. Ascan be seen in the figure below, the radiant asymmetrydiffers depending on the location of the emitter system,and whether it’s used for heating or cooling.With the insulation levels typically used today, radiantasymmetry does normally not cause any problemsdue to the moderate heating and cooling load theemitter has to perform. However, especially when usingceiling heating, a calculation must be made for a givenreference room.When designing radiant cooling systems, the dew pointis normally reached before radiant asymmetry problemsoccur. Can be calculated according to ISO 7726. 41 1.5 2 2.5 3 3.5 4.53.0 K4.0 K5.0 K6.0 K7.0 K8.0 K9.0 K10.0 KMaximumairvelocity,0.5mfromwall[m/s]Recommended comfort limit forsedentary personsHeight of cool wall [m]Δt (wall-room)Draught rateRadiant systems are low convective systems and willnot create any problems with draught. However, downdraught from a cold wall can put a limitation to thesystem. A cold wall can create draught as we know fromwindows. When designing wall cooling, the velocity onthe air need to be within the recommendation (Class Ais 0.18 m/s).11UPO NO R · FREE COOLING GUIDE
  12. 12. DissatisfiedFloor temperatureLocal discomfort caused by warm and cool floorsSurface temperaturesFor many years, people have chosen underfloor heatingsystems as the preferred emitter system, because of theperceived comfort of walking on a warm floor. Similarly,the question is if the occupants complaint about discom-fort when utilising the floor to remove heat (cooling).According to ISO 7730, the lowest PPD (6%) is foundat a floor temperature of 24 °C. A typical floor coolingsystem will have to operate with a minimum floortemperature of 20 °C, where the expected PPD wouldstill be under 10%. As will be seen later, such floortemperatures still provide a significant cooling effect,due to the large surface area being emitted.Vertical air temperaturedifferenceThe comfort categories are divided into A, B and Cdepending upon the difference between the airtemperature at floor level and at a height equivalent toa seated person. As can be seen below, the temperaturedifference must be under 2°C in order to reachcategory A.CategoryVertical air temperature difference a°CA < 2B < 3C < 4a) 1,1 and 0,1 m above floorA study done by Deli in 1995 shows the correlationbetween the ΔT floor surface/room (difference betweenthe floor surface temperature and the dimensionedroom temperature) and the vertical air temperaturedifference.Vertical temperature profile with different emitter systems[°C]18 20 22 2624Ideal heating Underfloor heatingRadiant ceiling heating External wall radiator heatingTemperature profile radiant cooling[°C]18 20 22 2624Radiant floorcoolingRadiant ceilingcoolingRadiant wallcoolingCorrelation between the temperature difference floor surface to roomand the vertical air temperature difference (Deli, 1995).The study concludes that up to a ΔT 8K, the comfortcategory is still A. This would equal a floor temperatureof 20 °C and a dimensioned room temperature of28 °C. The dimensioned room temperature must bebelow 26 °C and similarly above a floor temperatureof 20 °C in order to reach comfort class B. Hence, thevertical air temperature difference will in practice notcause a indoor climate below category A.As the pictures below show, different emitter systemsprovide different temperature gradients in a room.Clearly, a radiant heating system in the floor providesa temperature gradient closest to the ideal. Similarly,a radiant cooling system in the ceiling provides atemperature gradient closest to the ideal.00,511,522,532 4 6 8 10ABΔT floor surface roomVerticalairtemperaturedifference[K]0,1 - 1,1 m12 UPONOR · FREE COOLING G UIDE
  13. 13. Thermal transfer coefficientThe thermal transfer coefficient is an expression of howlarge an effect per m2the surface is able to transfer tothe room, per degree of the temperature differencebetween the surface and the room. The figure belowshows the thermal transfer coefficient for differentsurfaces for heating and cooling respectively.Due to natural convection, the floor provides thebest thermal transfer coefficient for heating while theceiling provides the best thermal transfer coefficient forcooling.Dew point limitationsIn order to secure that there is no condensation on thesurface of the emitter in the room the supply watertemperature should be controlled so that the surfacetemperatures of the emitter always is above dew point.In the diagram below, the dew point temperatures canbe found under different levels of relative humidity(RH):2423222120191817161514131211109840 45 50 55 60 65 70 75 80Dewpointtemperature[°C]Relative humidity RH [%]Room temp. 26 °CRoom temp. 25 °CRoom temp. 24 °CRoom temp. 23 °CAll emitter systems, whether it is pure air-based,radiators or pure radiant systems, are bounded by theirability to transfer energy. The capacity of any radiantemitter systems is limited by the heat flux density, whichdiffers depending on the location of the emitter, i.e.floor, wall or ceiling. The heat flux density can be usedto calculate the capacity of the emitter, also known asthe thermal transfer coefficient. Specifically regardingcooling, any radiant emitter will need to work within thedew point limitations in order to avoid moisture on thesurface and within the construction.Heat flux densityThe ability of a surface to transfer heating or coolingbetween the surface and the room, is expressed by theheat flux density. According to EN 1264/EN 15377,the values below can be used to express the heat fluxdensity.Floor heating, ceiling cooling: q = 8.92 (θs,m- θi)1.1Wall heating, wall cooling: q = 8 (| θs,m- θi|)Ceiling heating: q = 6 (| θs,m- θi|)Floor cooling: q = 7 (| θs,m- θi|)Whereq is the heat flux density in W/m2θs,mis the average surface temperature (always limitedby dew point)θiis the room design temperature (operative)4. Capacity and limitations of radiant emittersystems105015Surface heating and coolingFloor Ceiling WallHeatingCooling[W/m2K]Thermaltransfercoefficient13UPO NO R · FREE COOLING GUIDE
  14. 14. Emitter surface and humidityDesign temperatures for cooling systems are specifiedaccording to the dew point. The dew point is defined bythe absolute humidity in the room and can be estimatedfrom the relative humidity RH and the air temperature.The cooling capacity of the system is defined by thedifference between the room temperature and the meanwater temperature.Often standard design parameters for cooling systemsare an indoor temperature of 26 °C and a relativehumidity of 50%. At the dew point, condensationwill occur on the emitter surface. In order to avoidcondensation, the emitter surface temperature has to beabove the dew point temperature.For radiant floor cooling a minimum surface temperatureof 20 °C is required, which means that only when therelative humidity exceeds 70% in the room, the riskof condensation occurs, because that corresponds toa relative humidity of 100% at the emitter surface.Radiant cooling from the ceiling is limited by the radiantasymmetry between the surface of the emitter and theroom temperature recommendation is that it should notexceed more than 14 K. For standard conditions (26 ºC,50% RH) the surface of the emitter usually reaches thedew point before the radiant asymmetry limit.Distribution pipes and manifoldsIn any cooling system where you have distribution pipesor manifolds you have to be aware of that these partsof the system also have a risk of condensation becausethey sometime operates below the dew point. Insulationof distribution system is often necessary in order toavoid condensation.Design temperatureThe design supply water temperature of the systemdepends on the type of surface used, the design indoorconditions (temperature and relative humidity) and thecooling loads to be removed. It should be calculated toobtain the maximum cooling effect possible from thesystem.The capacity and mean water temperature for radiantfloor cooling depends on the floor construction, pipepitch and surface material. To have the highest possiblecapacity of the system you should design your floorconstruction so the surface temperature is equal to theminimum temperature of 20 °C.The capacity and mean water temperature for radiantcooling from the ceiling is calculated, or can be readdirectly, in the capacity diagram of the cooling panels.To have the highest possible capacity of the system youshould design as close to the dew point as possible.Theoretical capacities ofembedded radiant coolingTaking both ISO 7730 (surface temperatures, radiantasymmetry, and down draught) and the dew pointlimitations into account, the following surfacetemperature limitations exist.Surface temperature limitationsWith these surface temperature limitations in mind, themaximum capacities of different radiant emitter systemscan be calculated. The results are shown in the figurebelow.Maximum heating a cooling capacitiesIn theory, the highest heating capacity can be achievedfrom the wall. Since space is limited due to windowsand other things hanging on the wall, the real heatingcapacity from walls is significantly reduced. Hence, thebiggest capacity can be achieved by heating from thefloor, and cooling from the ceiling. In practice, eithera floor system or a ceiling system is installed and usedfor both heating and cooling. A floor system shouldbe chosen if the heating demand is dominant and aceiling system should be chosen if the cooling demandis dominant.35251545302040Floor Ceiling WallHeatingCoolingParimeterTemperature[°C]804001206020100140180160200Floor Ceiling WallHeatingCoolingParimeterHeatingandCoolingCapacity[W/m2]14 UPONOR · FREE COOLING G UIDE
  15. 15. 5. Ground heat exchangersGround conditionsWhen planning the use of ground heat exchangers,the ground conditions are of fundamental importance.Determining the ground properties, with respect tothe water content, the soil characteristics (i.e. thermalconductivity), density, specific and latent thermalcapacity as well as evaluating the different heat andsubstance transport processes, are basic pre-requisitesto determine and define the capacity of a ground heatexchanger. The dimensioning has a significant impacton the energy efficiency of the heat pump system.Heat pumps with a high capacity have unnecessaryhigh power consumption when combined with a poorlydimensioned heat source.With a higher water concentration in the ground, youget a better system capacity. Horisontal collectors arehence depending on the ground’s ability to prevent rainwater from mitigating downwards due to gravitation.The smaller the corn size in the soil, the better theground can prevent rain water from gravitation. Henceclay will provide a better performing ground heatexchanger than sand. Vertical collectors are dependingon being in contact with ground water. Hence the depthof ground water levels has an important impact on theperformance of a vertical ground heat exchanger.In addition to the water concentration, different groundtypes have different thermal conductivity. For examplerock has a higher thermal conductivity than soil, soground conditions with granite or limestone will give abetter performing ground heat exchanger than sand orclay.Soil typeThermal conductivity(W/m K)Clay/silt, dry 0.5Clay/silt, waterlogged 1.8Sand, dry 0.4Sand, moist 1.4Sand, waterlogged 2.4Limestone 2.7Granite 3.2Source: VDI 464015UPO NO R · FREE COOLING GUIDE
  16. 16. Ground heat exchangersWith ground heat exchangers, a distinction is madebetween horisontal and vertical collectors. These can befurther classified as follows:Horisontal:• Horisontal or surface collectors• Energy cagesVertical:• Boreholes• Energy piles and wallsThe suitability of the different collectors depends on theenvironment (soil properties and climatic conditions),the performance data, the operating mode, buildingtype (commercial or private), the space available andthe legal regulations.Horisontal collectorsCollectors installed horisontally or diagonally in theupper five meters of the ground (surface collector).These are individual pipe circuits or parallel piperegisters which are usually installed next to the buildingand in more rare cases under the building foundation.Energy cagesCollectors installed vertically in the ground. Here, thecollector is arranged in a spiral or a screw shape. Energycages are a special form of horisontal collectors.BoreholesCollectors installed vertically or diagonally in theground. Here one (single U-probe) or two (doubleU-probe) pipe runs are inserted in a borehole inU-shape or concentrically as inner and outer tubes.Energy pilesCollectors build into the pile foundations that areused in construction projects with insufficient loadcapacity in the ground. Individual or several pipe runsare installed in foundation piles in a U-shape, spiral ormeander shape. This can be done with pre-fabricatedfoundation piles or directly on the construction site,where the pipe runs are placed in prepared boreholesthat are then filled with concrete. Most often energypiles are used for larger commercial buildings.16 UPONOR · FREE COOLING G UIDE
  17. 17. Ground temperature profileThe figure below shows a generic temperature profile inthe ground for each season during the year.The closer to the ground surface, the higher theinfluence from the outside temperature and solarradiation. Hence not surprisingly, the highesttemperatures are found in late summer and thelowest temperatures in late winter. The reason for thetemperatures being higher in late autumn than latespring, has to do with the ground’s ability to storeenergy. After a warm summer period, the groundremains relatively warm during the autumn. Groundtemperatures stabilize below 10-15 m. It is clear fromthese ground temperature profiles that the coolingcapacity is higher below 15 m. Hence vertical collectorsystems provides a better cooling capacity thanhorisontal collector systems.Primary supply temperaturesThe temperatures mentioned in the previous sectionare often referred to as the undisturbed groundtemperature. Depending on the thermal resistancebetween the collector and the surrounding ground, thetemperature of the fluid in the collector will be higherthan the surrounding ground.0 20200151050 2010 15510 1551. February1. May1. November1. AugustTemperature (earth’s surface) [°C]Depthinsoil[m]Temperature (depth) [°C]Dimensioning of ground heatexchangers for free coolingThe first thing to decide is whether the ground heatexchanger shall be used for heating only or for bothheating and cooling. As demonstrated in this guide,new built low energy houses will often have substantialcooling loads. It is therefore highly recommendable touse the ground heat exchanger for free cooling in thesummer period. A combined use for heating and coolingalso balances of the ground temperature during theyear and leaves the ground environment undisturbed.Existing guidelines for dimensioning ground heatexchangers are typically based on the peak load for theheating demand. But in order to ensure that adequatecooling capacity is available in the summer season, itis recommend doing a design check for the maximumcooling load as well.Dimensioning for the heat load should be done basedon the peak load for space heating plus the domestichot water need. As a heat pump is used for coveringthe heat load, the COP of the heat pump on thecoldest day (design day) should be applied in thedesign calculation. In addition to this, the specificcharacteristic of the chosen heat exchanger and thethermal conditions in the ground must be taken intoaccount.Dimensioning for the cooling load should be donebased on valid information of the maximum coolingload in the building. Free cooling operates without aheat pump. It is therefore vital that the thermal capacityof the ground heat exchanger is able to fully cover themax cooling load (no COP is included). In residentialbuildings in Northern Europe the cooling need willnormally be covered with the capacity derived fromthe heating requirements. But a design check is alwaysrecommended.In special cases in residential buildings and typically inoffice buildings, the cooling need will be dominant andthus the design driver. In such case vertical collectorsare normally recommended as the deeper groundtemperatures are sufficiently stable and independent ofsurface temperature and solar radiation. If a horizontalsystem is chosen, the space requirements can be acapacity limitation. Designing for inadequate coolingcapacity on the warmest summer days may thenbe necessary compromise, but should be evaluatedcarefully.17UPO NO R · FREE COOLING GUIDE
  18. 18. Dimensioning examplesIn order to dimension ground heat exchangers cer-tain information has to be considered. First of all anestimation of the physical properties of the ground isneeded. Normally its possible to obtain local grounddata (thermal conductivity etc.) from local databasesor authorities. The figures below show the capacity fordifferent collectors.Horisontal collectors Energy cage Vertical collectorsPipe size 25, 32 and 40 mm Normal 32 mm XL 32 mm 40 mmCapacity cooling 7-28 W/m2800-1120 W 1000-1500 W 30-70 W/mDimensioning temperature,supply/return17-20 °C 14-17 °C 10-13 °C 10-13 °C*) Energy cage; normal height is 2.0 m, andXL height 2.6. Required depth is 4 m.Flow and pressure drop in the collectorWhen the cooling need is defined, the flow can becalculated. When using ground collectors, the waterused has to be mixed with anti-frost liquid. Hence,the specific heat capacity and density in the brine isCooling need[kW]Ethanol Monoethylenglyciol PropylenglycolFlow [kg/s] Flow [l/s] Flow [kg/s] Flow [l/s] Flow [kg/s] Flow [l/s]2 0.16 0.15 0.18 0.19 0.17 0.183 0.24 0.23 0.27 0.28 0.26 0.274 0.32 0.31 0.36 0.38 0.34 0.365 0.40 0.38 0.45 0.47 0.43 0.456 0.48 0.46 0.54 0.56 0.51 0.54different from the physical properties of pure water.The table below shows the required flow of often usedbrines for providing different cooling capacity.When calculation the pressure loss in the collector theflow is divided equally up in the number of loops. Forvertical collectors the total pressure loss is normallyvery low hence the pressure is equalized and it is onlythe pressure loss in the feeding pipe has an influence.For horisontal collectors and partly energy cagesthe pressure loss has to be calculated in order to besure that the pump will be able to circulate the waterthrough the collector and the cooling exchangerincluding manifolds and valves.Example: 4 kW installationsHorisontal collector extractionpower15 W/m2Liquid MonoethylenglycolTotal flow 0.38 l/s, 1.37 m3/hDiameter of collector Ø 32 mmIn the diagram below, the pressure loss in theground collector should be maximum 34 kPa at thedimensioning conditions, and the ground collectorshould be dimensioned so that the pressure loss in eachloop is less than 34 kPa.Pump diagramAvailable pressure for the primary circuit.CP1CP20 0.5 1 1.5 2 2.5 350403020100Pressure loss [kPa]Rate of flow [m3/h]18 UPONOR · FREE COOLING G UIDE
  19. 19. 6. Free cooling in combination with different heatsourcesHeating mode, the free cooling is deactivated Cooling mode, the free cooling is activatedThe illustrations below shows a ground heat exchangercombined with a radiant system in heating mode andcooling mode. In this example a ground sourced heatpump is providing heating to domestic hot water(DHW), space heating, and for heating up the incomingventilation air. This could of course be utilized withother heat sources such as boilers or district heating.Free cooling is provided through a special pump andexchanger group (see chapter 8) that supplies coldwater/brine from the ground heat exchanger directly tothe radiant emitter system and possibly the incomingventilation air. In cooling mode, the heat pump will onlybe active for domestic hot water generation.As one can see from the grey connection lines the pumpand exchanger group is not active in heating mode.Similarly, the connection lines from the heat pump (orany other heat source) to the emitter systems are in-active in cooling mode.If a boiler or district heating system is used as heatingsource, the ground heat exchanger will only work duringcooling (also known as a bivalent system). If a groundsource heat pump is used as heat source, the groundground heat exchanger will work both during heatingand during cooling (also known as a monovalentsystem).19UPO NO R · FREE COOLING GUIDE
  20. 20. Embedded emitters are the key to any radiant system.In order to have an energy efficient and comfortablesolution, the emitter system has to be designed tothe construction but also to the task it has to solve.There are many types of constructions for floor, walland ceilings. Uponor offers emitters that can meet therequirements of all types of installations. All emittersare able to provide heating and cooling. However, someemitters are more efficiently than others. The mostefficient cooling system is placed in the ceiling, but theheating efficiency is lower whereas an emitter system inCapacity of different radiantemitter systemsIn order to calculate the capacity of the radiant emitter,it is important to know the construction in which theembedded emitter is integrated, including the surfacematerial on top of the construction. In general, there arethree factors that influence on the capacity of a radiantemitter system:• Thermal resistance in the surface construction RB• Pipe pitch, i.e. the distance between the pipes T• Thermal conductivity in the construction materialIn practice, this means that when designing the floorconstruction, the performance of the radiant system canbe optimised by choosing the right construction, pipelayout and surface material.Floor installation Wall installation Ceiling installationthe floor has the highest heating efficiency, but with alower cooling efficiency.Another important factor is the supply watertemperature. Radiant emitter systems operate on arelatively low temperature for heating, and a relativelyhigh temperature for cooling. A radiant system shouldbe designed for the lowest possible temperature forheating and the highest possible temperature forcooling. This secures a heating/cooling system withhigh energy efficiency and optimal conditions for theheating and cooling supply.Example: floor construction7. Choosing and dimensioning the radiant emittersystem20 UPONOR · FREE COOLING G UIDE
  21. 21. Pipe pitch, i.e. distance between thepipesThe pipe pitch, i.e. the distance between the pipes inthe embedded construction, not only has an influenceon the capacity, but also on how equal the surfacetemperature is. This is especially important from acomfort perspective.The diagram shows the capacity of a concrete floorconstruction with  =1.8 W/(mK), and with differentkinds of surface material. The diagram illustrates thevariation of the capacity depending on the pipe pitch.A short distance between the pipes, gives a highercapacity and vice versa. For a combined heating andcooling system, it is recommended to use a relativelysmall distance  300 mm between the pipes, in orderto utilise free cooling and maintain an even surfacetemperature.Thermal conductivity in the constructionThe thermal conductivity in the construction has aneffect on the system’s ability to distribute heating andcooling in the thermal mass. A construction with a lowthermal conductivity requires a smaller pipe pitch, inorder to obtain an equal surface temperature variation.RλB= 0RλB= 0.05RλB= 0.10RλB= 0.15qCN(RλB= 0.15)qCN(RλB= 0)ΔθCNY = Specific thermal output qc[W/m2]X = Temperature difference betweenroom and cooling medium [θcK]45403530252015100.1 0.15 0.2 0.3 0.4 0.50.25 0.35 0.45Thermaloutputq[W/m2]Pipe spacing T [m]θm15.5 °C,14 mm parquetθm15.5 °C,7 mm parquetθm15.5 °C,10 mm tilesθm18.5 °C,14 mm parquetθm18.5 °C,7 mm parquetθm18.5 °C,10 mm tilesFloor surface temperature limit 20 °CThermal resistance in the surfaceconstructionThe thermal resistance in the surface construction has abig influence on the performance of the emitter. In thediagram, an example of a cooling curve where differentthermal resistance values from 0.00 to 0.15 m2K/W areshown. The curve shows that higher resistance gives alower capacity. All constructions with embedded radiantemitter systems will have a surface resistance that has tobe considered. In order to get the highest efficiency, theresistance value has to be as low as possible.Field of characteristic curves of a cooling systemFor dry constructions, high performance material likeheat distribution plates in aluminium or similar are usedto ensure optimal heating and cooling distribution.21UPO NO R · FREE COOLING GUIDE
  22. 22. Surface materialTiles 10 mm, = 1.0 W/mKSurface materialWood 14 mm parquet, = 0.014 W/mKInstallationprincipleCooling effectq [W/m2]θm15.5 °CCooling effectq [W/m2]θm18.5 °CCooling effectq [W/m2]θm15.5 °CCooling effectq [W/m2]θm18.5 °CWet floorinstallation42 40 33 24Installationintegrated inconstruction42 40 33 24Installation on thejoists28 20 27 19Dry floorinstallation28 20 27 19Installationbetween the joists24 17 18 14FloorinstallationRadiant floor constructions andcapacityRadiant floor systems are far more common thanceiling or wall systems, and can be used for cooling andheating. A radiant floor system can be installed in wetconstructions using concrete and screed, and in dryconstructions with heat emissions plates.A radiant floor has a cooling capacity of up to 42 W/m2limited by a surface temperature of 20 °C. The mostefficient installation is in a wet construction with con-crete or screed, because of its high heat conductivity,using a relatively short distance between the pipes, anda surface material with a low thermal resistance.In the figure below, an overview of the capacity inthe most common floor installations is shown withmean water temperatures of 15.5 °C and 18.5 °Ccorresponding to supply temperatures of 14 °C and17 °C with a T of 3 K over the emitter loops. Figuresare based on a room temperature of 26 °C and a surfacetemperature of 20 °C.22 UPONOR · FREE COOLING G UIDE
  23. 23. WallinstallationInstallationprincipleCooling effectq [W/m2]θm15.5 °CCooling effectq [W/m2]θm18.5 °CCooling effectq [W/m2]θm15.5 °CCooling effectq [W/m2]θm18.5 °CCooling effectq [W/m2]θm15.5 °CCooling effectq [W/m2]θm18.5 °CDry wallinstallation45 32Wet wallinstallation60 45Stud wallinstallation42 34Radiant wall constructions andcapacityRadiant wall systems are typically used as a supplementto floor and ceiling emitter systems for roomswith a higher need for cooling/heating. Instead ofdimensioning the floor or ceiling system according tothe room with the highest peak load, it can be designedaccording to the average and the peak room(s) can besupplemented with a wall emitter.A radiant wall system will be limited by the architectureand by the furnishing. Radiant wall systems have acooling capacity of up to 60 W/m2(active area) limitedSurface materialPlaster 10 mm,  = 0.7 W/mKSurface materialPlaster 11 mm,  = 0.24 W/mKSurface materialPlaster 11 mm,  = 0.23 W/mKby a surface temperature of 17 °C, in order to be withinthe limits of radiant asymmetry and to prevent draught.In the figure below, an overview of the capacity of themost common wall systems is shown with mean watertemperatures of 15.5 °C and 18.5 °C correspondingto supply temperatures of 14 °C and 17 °C with a Tof 3 K over the emitter system. Figures are based on aroom temperature of 26 °C and a surface temperatureof 20 °C .23UPO NO R · FREE COOLING GUIDE
  24. 24. InstallationprincipleCooling effectq [W/m2]θm15.5 °CCooling effectq [W/m2]θm18.5 °CCooling effectq [W/m2]θm15.5 °CCooling effectq [W/m2]θm18.5 °CCooling effectq [W/m2]θm15.5 °CCooling effectq [W/m2]θm18.5 °CWet ceilinginstallation75 55Dry ceilinginstallation59 42Suspendedceilinginstallation97 67CeilinginstallationRadiant ceiling constructionsand capacityRadiant ceiling systems are the most efficient systemsfor cooling, but can also be used for heating. Ceilingsystems have originally been developed for officeenvironments, but are also available for residentialconstructions using wet plaster or dry gypsum panels.Radiant ceiling systems have a cooling capacity of upto 97 W/m2. It is important to note that especially forceiling cooling, the surface temperature of the systemis in peak often very close to the dew point. Specialattention has to be taken for adequate dew pointcontrol.In the figure below, an overview of the capacity inthe most common ceiling systems is shown, withmean water temperatures of 15.5 °C and 18.5 °Ccorresponding to supply temperatures of 14 °C and17 °C with a T of 3 K over the emitter system. Figuresare based on a room temperature of 26 °C and a surfacetemperature of 16 °C.Capacity diagramsUponor offers a wide range of embedded emittersystems adapted to different kinds of constructions inthe floor, wall or ceiling. Whenever the choice of systemhas been selected, detailed diagrams can be used inorder to make the planning of the capacity. The diagramand example on next page shows a floor constructionwith the cooling and heating output of the emittersystem.Dimensioning diagram for coolingAnalogue to dimensioning for heating, the followingparameters must be considered:1. Cooling effect of the radiant area qc[W/m2]2. Thermal resistance in the surface construction RB[m2K/W]3. Pipe pitch, i.e. centre distance between the pipes T[cm]4. Difference between room temperature and meanwater temperature θc.= θi- θc[K]5. Recommended minimum surface temperature(20 °C)6. Difference between room temperature and surfacetemperature θv- θr, m[K]If three of the parameters above are known, theremaining parameters can be calculated using thediagram to the right.Surface materialPlaster 10 mm,  = 0.7 W/mKSurface materialPlaster 11 mm,  = 0.23 W/mKSurface materialPlaster 11 mm,  = 0.24 W/mK24 UPONOR · FREE COOLING G UIDE
  25. 25. 0,150,050,10T qH ΔθH,Ncm W/m2 K10 98,6 15,915 96,3 18,120 93,0 20,325 87,3 22,030 81,3 23,600,050,10201004060800,15T qC ΔθC,Ncm W/m2 K10 34,8 815 39,8 820 27,5 825 24,5 80204060800ΔθH= θHÐθi= 15 KT 15T 25T 30T 20T 10T 15T 20T 25T 10T 15T20T25HeatingCoolingT 30ΔθC= θiÐθC= 4 K10 K8 K6 KDimensioning example for coolingEstimating the dimensioned supply water temperature θV, Ausl.Given: qc= 29 W/m² θi= 26 °CRB= 0.05 m² K/WChosen pipe pitch = Vz 15 T: θv- θH= 2 KRead from the diagram: θc= 12 K θr, m- θi= 3.9 KCalculated: θr, m= i- 4.3 K θr, m= 21.7 °C(O.K., as this is above the recommendedminimum surface temperature (20 °C)θV, calc.= θi- θc- (θv- θR)/2θV, calc.= 26 - 9 - 2/2θV, calc.= 16 °CThermaloutputheatingqH[W/m2]ThermalresistanceRB[m2K/W]Thermaloutputcoolingqc[W/m2]Note: The required cooling effect can only be achievedif the median surface temperature and the dimensionedsupply temperature are above the dew-point. In orderto avoid condensation, a supply water controller such asUponor Climate Controller C-46 is needed.25UPO NO R · FREE COOLING GUIDE
  26. 26. The purpose of a control systems is to keep oneor more climate parameters within specified limitswithout a manual interference. Heating and coolingsystems require a control system in order to regulateroom temperatures during shifting internal loads andoutdoor temperatures. Good control systems adaptto the desired comfort temperatures while minimisingunnecessary energy use.In residential buildings two different types of controlsprinciples are common; zone control and individualroom control.In a zone control system, the temperature iscontrolled in a common zone consisting of severalrooms and heating and cooling is supplied evenly tothe full zone. Not all national building codes allowzone control systems as they have major shortfalls withcomfort as well as energy consumption.In low-energy buildings there will in particular be highvariations in the individual room heating and coolingloads (see figure 5.2). This means that lack of individualroom control causes the room with the highest demandto determine the heating or cooling supply to a fullzone, resulting in over temperatures and unnecessaryhigh energy consumption.An individual room control system is muchpreferable in order to meet room specific load variationsand individual comfort requirements. Due to highvariations in the individual room loads in low-energybuildings, an individual room control system is alsorequired to minimise the energy consumption.The basic principle in an individual room control systemis that a sensor measures the room temperature andregulates the heating or cooling supplied to the spacecontrolled in order to meet a user defined temperatureset point. The most well-know examples are radiatorswith thermostatic valves and underfloor heating systemswith room thermostats.In addition, room by room regulation provides thepossibility to shut down cooling in a specific room, suchas a bathroom or a room without cooling loads.21°C21°C21°C18°C18°C22°C22°C 20°C21°CTypical desired temperature (set points) in a single family house. Typical variation between individual room heat demands in alow-energy house.Regulation and controlLiving room KitchenRoom 1Bedroom Bath 1 Room 3 Entrance Bath 2Room 226 UPONOR · FREE COOLING G UIDE
  27. 27. The self-regulating effect inunderfloor heatingRadiant floor heating and cooling benefits from asignificant effect called ”self control” or “self regulatingeffect”. The self regulating effect occurs because theheat exchange from the emitting floor is proportionalto the temperature difference between the floor andthe room. This means that when room temperaturedrifts away from the set point, the heat exchange willautomatically increase.The self regulating effect depends partly on thetemperature difference between room and floor surfaceand partly on the difference between room and theaverage temperature in the layer, where the pipes areembedded. It means that a fast change of the operativetemperature will equally change the heat exchange.Due to the high impact the fast varying heat gains(sunshine through windows) may have on the roomtemperature, it is necessary that the heating system cancompensate for that, i.e. reduce or increase the heatoutput.Low-energy houses will largely benefit from the selfregulating effect, because the temperature differencebetween floor and room will be very small. A typicallow-energy house has on average for the heatingseason a heat load of 10 to 20 W/m² and for this size ofheat load, the self regulating effect will be in the rangeof 30 - 90%.Self-regulating effect. UFH/C outputs for different temperaturesbetween room and floor surface.Functional description ofUponor Control SystemIndividual room control with traditionalon/off functionalityFor a radiant floor heating and cooling system, thecontrol is normally split up in a central control andindividual room controls. The central control unit isplaced at the heat source. It controls the supply watertemperature according to the outside temperaturebased on an adjustable heat curve. The individual roomcontrol units (room thermostats) are placed in eachroom and controls the water flow in the individualunderfloor heating circuit by ON/OFF control with avariable duty cycle. Its done according to the set-pointby opening and closing an actuator placed at the centralmanifold.Individual room control with DEMtechnologyUponor’s Dynamic Energy Management controlprinciple is an advanced individual room system basedon innovative technology and an advanced self learningalgorithm. Instead of a simple ON/OFF control, theactuators on the manifold supplies the energy to eachroom in short pulses determined based on feedbackfrom the individual room thermostats.Uponor Control System DEM is self learning and willremember the thermal behavior of each room. Thisensures an adequate and very accurate supply ofenergy, which means better temperature control andenergy savings.Typical behaviour in a heavy floor construction, where UponorDEM technology ensures that a minimum of energy is lost to theconstruction. Compared with traditional on/off regulation, savingfigures between 3-8% can be obtained.192021222324252627°Ccba= Floor surface temperature= Room temperaturea heating = 19.1 W/m2b heating = 13.9 W/m2c cooling = -10.5 W/m2TimeUponor DEMtechnologySaved energy whenusing Uponor DEM technology Actuator on/offLost energy whenusing Uponor DEM technologyHighertemperature+-LowertemperatureThermostat setpoint 20°CTime27UPO NO R · FREE COOLING GUIDE
  28. 28. Zone controlWhen using zone control for a radiant floor heatingand cooling system, the central controller is normallyplaced at the heat source. It controls the supply watertemperature according to the outside temperaturebased on an adjustable heat curve. The manifold systemSimple zone control, the central controller provides a regulated supplytemperature based on the outdoor/indoor temperature.MC-46230 V AC230 V AC24 V DCMC-56C-56C-56I-76H-56T-75T-55T-54has no actuators and normally the system works at aconstant flow with temperature regulation based ona reference thermostat is placed in one of the mainrooms.Individual room control, the central controller provides a regulatedsupply water temperature based on the outdoor/indoor temperature andthe room thermostat controls the room temperature by using actuators.C-46M230 V AC28 UPONOR · FREE COOLING G UIDE
  29. 29. The Uponor Pump and exchanger group, EPG6,is designed for a separate cooling supply andtemperature control for ground source freecooling. The EPG6 is pre-mounted and readyto install in the installations. Together withthe Uponor ground collectors it is readyto provide free cooling for radiant emittersystems.The EPG6 can be integrated in HVACinstallations for applications a separate supplyof cooling needs to be provided through aheat exchanger (e.g. from a ground collector).The EPG 6 is controlled by Uponor ClimateController C-46, which is able to adjust thesecondary temperature supplied to the emitter8. Uponor Pump and exchanger group (EPG6) forground sourced free coolingsystem and interact with the Uponor ControlSystem used to control the emitter system.Uponor Climate Controller C-46 is also able tocontrol the temperature according to the dewpoint, in order to prevent condensation.The primary side of the system is driven bya circulation pump, to circulate the fluidin the brine circuit and a 3-way mixingvalve for controlling the primary flow, inorder to maintain the correct temperatureon the secondary side. The exchanger thatexchanges the brine from the ground circuitwith the water in the emitter system isdesigned for a capacity up to 6 kW.12345678912345678910101111Secondary circlet,to emitter systemPrimary side, ground collectoror other cooling supplyComponent overviewPrimary sideThe primary side of the system (ground collector) isconnected to the EPG6 and will work as the heat sink.The mixing valve (1) will adjust the flow of the primaryside and is controlled by the Uponor Climate ControllerC-46 (10), which opens and closes the valve to theadjusted supply temperature on the secondary sidemeasured by the supply sensor (7). The primary pump(2) will circulate the fluid in the brine circuit throughthe exchanger (4) and will shut down when there is norequest from the secondary control system. The fillingand air valve (3) is used to fill up the primary systemwith brine. Connection to an expansion tank and safetyvalves can be done on the connection valve (9).Secondary sideThe secondary ball valves (5 and 6) are shutting downthe secondary side of the system, and have a ballvalve (5) including a check valve to prevent backflowin the system. The blind piece (8) can be replacedby a circulation pump, if no other pump is used forthe secondary side. The secondary pump has to beconnected to the Uponor Climate Controller C-46 (10).3 way mixing valve Kvs7 m3/hPrimary circulation pump Grundfos Alpha 2L 26-60Filling and air valve G ¾”Heat exchanger 6 kW SWEP ESTH x 40/1P-SC-S 4 x ¾”Ball valve with integrated check valve and thermometer Rp 1”Ball valve with integrated thermometer Rp 1”Sensor pocket (supply)Blind piece 180 mm G 1¼” for secondary circulation pumpFilling valve G ¾”Uponor Climate Controller C-46Primary connection Rp 1¼”29UPO NO R · FREE COOLING GUIDE
  30. 30. DimensionsPump diagramAvailable pressure for the primary circuitRp 1¼360580Rp 1 Rp 112523080Rp 1¼CP1CP20 0.5 1 1.5 2 2.5 350403020100Pressureloss[kPa]Flow rate [m3/h]30 UPONOR · FREE COOLING G UIDE
  31. 31. Control principleControls is required for the primary system as well as thesecondary system.Since the primary control of the heating mode isseparated from the primary control of the cooling mode,the change-over between heating and cooling mustbe defined. This can be done either automatically if acommunication interface can be setup between theUponor Climate Controller C-46 and the heat source orthrough a manual switch if it is not possible to setup acommunication interface.Because a radiant emitter system can act for bothheating and cooling, the secondary system can becontrolled by one system as described below.Secondary control – heating and coolingFor the secondary control of the emitter system,Uponor recommends to apply individual room control,in order to provide energy efficiency and comfort. Theindividual control system also secures that cooling canbe deactivated in single rooms/zones, e.g. in bathroomswhere cooling might not be required. The UponorControl System offers a long range of benefits for theuser and can be integrated with the primary controllerfor cooling, Uponor Climate Controller C-46.Primary control – coolingThe primary control of the cooling system is provided bythe EPG6 which includes the Uponor Climate ControllerC-46 that manages:• the supply temperature of the system• pump management of primary and secondarypumps• change-over between heating and cooling• dew point management with up to six wireless dewpoint sensors (Uponor Relative Humidity SensorH-56)In order to eliminate therisk of condensation on theemitter surface, dew pointmanagement is an essentialpart of the cooling system.The relative humidity sensorsmeasure the relative humidityand the temperature in theroom, and Uponor ClimateController C-46 uses the datato calculate the dew point.Thereby, it is able to securethat the supply water temperature never gets too low,and that no condensation will occur on the emittersurface.C-56 I-76T-75H-56 T-54 T-5531UPO NO R · FREE COOLING GUIDE
  32. 32. Hydraulic change-over between heatingand coolingUponor recommends using a diverting valve in thesecondary heating/cooling distribution system, whichopens and closes when changing between heating andcooling. The diverting valve is controlled by the UponorClimate Controller C-46 either directly through a 24 Vactuator or through a relay for a 230 V actuator. Thediverting valve is activated by the change-over signalbetween the heating and cooling modes.Heating modeIn heating mode, the free cooling system is deactivated.Hence, no pumps are running and the diverting valve isclosed (the flow goes straight through).Cooling modeIn cooling mode, the free cooling system is activated.Hence, pumps are running and the diverting valve isopen. An internal circuit is secured for the heat sourcefor producing domestic hot water.32 UPONOR · FREE COOLING G UIDE
  33. 33. TWM643123456787958129Installation examplesBrine to water heat pump with Uponor EPG6The system diagram illustrates a Uponor free coolinginstallation using a ground collector and Uponor EPG6in combination with a brine to water heat pump forspace heating and domestic hot water.The EPG6 (3) is connected to a Uponor ground collector(1) on the primary side of the free cooling installation. Ifmore than one ground loop is installed, a manifold canbe used to connect the ground loops.The secondary side of the EPG6 is connected to theheating pipe system before the manifold of the radiantsystem (4).A diverting valve (7) is used to switch the flow directionin the hydraulic system between heating and cooling(diverting valve to open when cooling is activated).When switching between heating and cooling, the heatpump must be in a position where it only producesdomestic hot water (typically “summer mode” can beused).The Uponor Climate Controller C-46 can send anexternal signal to the heat pump when switchingbetween heating and cooling or it can be donemanually with a relay switch. Contact the heat pumpmanufacturer in order to check the possibilities.Ground collectorBrine to water heat pumpUponor EPG6 with Uponor Climate Controller C-46Radiant emitter systemBuffer tankDomestic hot water tankDiverting valveNon return valveSecondary circulation pump33UPO NO R · FREE COOLING GUIDE
  34. 34. M6258741312345678Condensing boiler with Uponor EPG6The system diagram illustrates a Uponor free coolinginstallation using a ground collector and Uponor EPG6in combination with a gas/oil boiler for space heatingand domestic hot water.The EPG6 (3) is connected to a Uponor groundcollector (1) on the primary side of the free coolinginstallation. If more than one ground loop is installed, amanifold can be used to connect the ground loops.The secondary side of the EPG6 is connected to theheating pipe system before the manifold of the radiantsystem (4).A diverting valve (7) is used to switch the flow directionin the hydraulic system between heating and cooling(diverting valve to open when cooling is activated).When switching between heating and cooling, the boilermust be in a position where it only produces domestichot water (typically “summer mode” can be used).The Uponor Climate Controller C-46 can send anexternal signal to the boiler when switching betweenheating and cooling or it can be done manually with arelay switch. Contact the boiler manufacturer in order tocheck the possibilities.In the example below, a solar collector is supporting theboiler for space heating and domestic hot water but isnot interacting with the cooling system.Ground collectorCondensing boilerUponor EPG6 with Uponor Climate Controller C-46Radiant emitter systemSolar tankSolar panelDiverting valveSecondary circulation pump34 UPONOR · FREE COOLING G UIDE
  35. 35. M123123Free cooling with Uponor EPG6The system diagram illustrates a Uponor free coolinginstallation using a ground collector and Uponor EPG6as a stand-alone system.The EPG6 (3) is connected to a Uponor groundcollector (1) on the primary side of the free coolinginstallation using the same supply line as to the heatpump. If more than one ground loop is installed, amanifold can be used to connect the ground loops.The secondary side of the EPG6 is connected to theheating pipe system before the manifold of the radiantsystem (4).Please note that a circulation pump (180 mm) has to beadded to the EPG6 in order to circulate the secondarycircuit. There is a blind piece on the EPG6 that can bereplaced with a pump.The activation of the EPG6 cooling module can bedone automatically through the Uponor ClimateController C-46 included in the EPG6 or throughanother external signal through the climate controller.Ground collector (or bore hole)Uponor EPG6 with Uponor Climate Controller C-46Radiant emitter system35UPO NO R · FREE COOLING GUIDE
  36. 36. Operation mode of UponorClimate Controller C-46Two possible operation modes for cooling are describedbelow. The most typical operation mode of UponorClimate Controller C-46 is heating and cooling modewhen the controlled radiant system is used for bothheating and cooling emitter. In the case where a radiantceiling or wall system is installed purely for coolingpurposes, the operation mode is set to cooling mode.This could apply to an example where cooling is neededin an energy renovated house with radiators.Operation mode heating and cooling ofUponor Climate Controller C-46When having a combined heating and cooling systemwhere you change between heating and cooling, theclimate controller always have to be in heating andcooling mode, even though the climate controller is notused as the primary controller for heating.Uponor > Main menu > Control settings > Advanced control > Operationmode. Note that the startup wizard will start when changing mode.Heating min./max. supply UponorClimate Controller C-46In the case of combined heating and cooling system,where you can change between heating and cooling,the climate controller C-46 must always be set toHeating and cooling mode, even when the climatecontroller is not used as primary controller for heating.In this case the heating setting in the climate controllermust be neutralized as follows:Uponor > Main menu > Control settings > Heating > Min./max supplyOK, also covered in startup wizard.Operation of Uponor ClimateController C-46Uponor EPG6 is delivered integrated with UponorClimate Controller C-46. It is important that the settingsand parameters are programmed to fit the designedsystem. A detailed user manual describes all settingsand parameters.Wizard – great installation guideWhen Uponor Climate Controller C-46 is started forthe very first time, it guides the installer to make thenecessary primary settings of the system. Wizard helpsyou step by step through the installation process. Onthe display, the installer can read all about the set-upand what to do next. The installation wizard is alsostarted after changing or resetting the operation mode.Quick menu – gives easy access to basic settingsMade for end-users: The quick menu consists of a seriesof screens easily accessible from the Uponor screen.These screens display readings for daily use. If theUponor Climate Controller C-46 is set to installer accesslevel, it is also possible to modify some parameters.Main menu – all informations and settings on thewholeThe main menu and all its sub-menus are used fordisplaying any accessible information, parametersettings, and selecting operating modes that areaccessible in the system.Operating modeHeatingHeating and coolingCoolingMin./max supplyMin5.0 °CMax8.0 °C36 UPONOR · FREE COOLING G UIDE
  37. 37. Uponor > Main menu > Control settings > Cooling > Dew pointThe functions require Uponor Relative HumiditySensor H-56 and can handle up to six sensors, placedin different rooms/zones. The sensor mode functionallows to decide which value to use in the dew pointcalculation. It can be set as an average or maximumvalue of the sensor. For cooling application, it is alwaysrecommended to use the maximum sensor mode.Uponor > Main menu > Control settings > Cooling > Sensor modeResulting supply water temperaturesThe dew point control is activated if the cooling supplysetpoint is below the calculated dew point. The functionoverrules the cooling supply setpoint, and automaticallyadapts the temperature according to calculated dewpoint based on the measured room temperature andhumidity of the room/zone. The resulting supply watertemperature is the calculated dew point + the dew pointmargin.Uponor Climate Controller C-46 calculates the dewpoint using data from Uponor Relative Humidity SensorH-56, i.e. relative humidity and temperature. It isdisplayed in the quick menu.Cooling mode onlyIf the system works as a stand alone cooling systemwithout any change over between heating and cooling,cooling mode is chosen:Uponor > Main menu > Control settings > Advanced control > Operationmode. Note that the startup wizard will start when changing mode.Dew point managementparameters and settingsIn the operation mode cooling, indoor compensatedsupply with dew point control will help you to preventcondensation problems if the actual condition in theroom/zone is different from the design criteria.The supply water set point is referring to the designsupply temperature of the system, and is the absoluteminimum temperature that the Uponor ClimateController C-46 will provide. The supply temperatureshould be set according to the design of the emittersystem, taking into account the limitations factors, suchas surface temperature and dew point.Uponor > Main menu > Control settings > CoolingThe function also allows using a dew point margin asan extra safety to compensate for having the variationin room conditions, occupation of the room, etc. Thedew point margin can be adapted to the installation.A smaller margin will improve the cooling power, whilea larger margin will reduce the risk of condensation.The installation needs to be checked after startup andre-configuration. If condensation occurs, the dew pointmargin must be increased.Sensor modeAverageMaximumCalculated dew point18.3 °CDew point margin1Operating modeHeatingHeating and coolingCoolingSupply setpoint14.0 °C37UPO NO R · FREE COOLING GUIDE
  38. 38. Uponor > Main menu > Control settings > H/C switchover > Bus masterUponor > Main menu > General settings > General purpose output >ModeHeating and cooling change-over: Uponor Climate ControllerC-46Change-over between heating and cooling can alsobe handled by Uponor Climate Controller C-46, eitherautomatically using the indoor-outdoor temperaturecontrolled switch-over, or a manual command. Whenthe change over from the climate controller is activated,the hydraulic change-over with the diverting valve ismanaged by the general purpose output (11 and 12)that sends out a potential free signal. At the same time,the same signal can be used through a relay to send asignal to the heat source. The automatic change-overindoor, outdoor and trigger parameters have to beselected in the climate controller, as well as the functionof the general purpose output.The heat source must be able to receive potential free signal, i e sense adry contact closure. The supplier of the heat source will be able to giveguidelines of which signal is availableHeating and cooling change-over: external signalWhen having a combined emitter system for heatingand cooling, the change-over between heating andcooling system can be managed by Uponor ClimateController C-46 or through it. The climate controllerhas several options for how to switch between heatingand cooling. The most common is to use the generalpurpose input (5 and 6) in the climate controller, tocontrol that the system should switch from heating tocooling. The general propose input is a contact sensinginput that can be connected to a relay in the heatsource or a manual switch. The heating and coolingchange-over behavior needs to be configured in UponorClimate Controller C-46. The hydraulic change-over withthe diverting valve is managed by the general purposeoutput (11 and 12) that sends out a free signal using adry contact output.Contact closing output from the best source or from manual switch. Thesupplier of the heat source will be able to give guidelines of which signalis available.Activating the general purpose output needs to beconfigured in Uponor Climate Controller C-46.Uponor > Main menu > Control settings > H/C switchoverH/C switchoverBus masterBus slaveNo busBus masterIndoor and outdoorSupply water temp.General purpose inputGeneral purpose outputInactiveH+C commandsFault signallingV ~ 50 HzN L0-10V-NL+230 V ~50 Hzμ 2 A230 V ~G H I J K L230 Vμ 2A24VAC/DC1 2 3 4 5 6 7 8 9 10 11 125 6C-56Reset24 V230 V1234512345Heat pumpPumpDiverting valveActuator 24 VRelay (e.g. Uponor 1000517)12345V ~ 50 HzN L0-10V-NL+230 V ~50 Hzμ 2 A230 V ~G H I J K L230 Vμ 2A24VAC/DC1 2 3 4 5 6 7 8 9 10 11 125 6C-56Reset24 V12345Heat pumpPumpDiverting valveActuator 24 VRelay (e.g. Uponor 1000517)38 UPONOR · FREE COOLING G UIDE
  39. 39. Uponor > Main menu > Control settings > H/C switchoverUponor > Main menu > Control settings > H/C switchover > Bus masterUponor > Main menu > General settings > General purpose output >ModePump management EPG6The EPG6 is equipped with a Grundfoss circulationpump Alpha 2L 25-60 for circulation of the primarybrine circuit. The pump is powered up through theUponor Climate Controller C-46 and prepared for pumpmanagement. The actuator for the three-way mixingvalve is also powered by the climate controller andconnected to the control signal. The signal adjusts thevalve and secures the correct supply temperature usingthe supply sensor which is also pre-installed in theEPG 6.In order to get the correct operation of the mixingvalve, motorised valves have to be selected in UponorClimate Controller C-46. The pump management alsohas to be selected in the climate controller and in orderto get optimal control, “bus control” is selected. The buscontrol will react on the secondary control system andthe pump will stop if there is no demand to the zones.The secondary pump can also be connected throughthe Uponor Climate Controller C-46, but the pump relayhas a limit of 100 W for the primary and the secondarypump. The primary pump has a maximum consumptionof 45 W. Hence, 55 W is left for the secondary pump.An alternative is to connect the secondary pump to thesecondary controller, i.e. Uponor Controller C-56.Uponor > Main menu > Control settings > Advanced control > PumpmanagementPump managementInternal controlBus controlAlways on230 Vμ 2A24VAC/DC1 2 3 4 5 6 7 8 9 10 11 12C-56ResetDEM65Bus masterIndoor and outdoorSupply water temp.General purpose inputGeneral purpose outputInactiveH+C commandsFault signallingH/C switchoverBus masterBus slaveNo bus39UPO NO R · FREE COOLING GUIDE
  40. 40. 2012-12-18_UKProduction:UponorAB,IC/EL,Virsbo;SwedenUponor Corporationwww.uponor.comUponor reserves the right to make changes, without prior notification, to the specification ofincorporated components in line with its policy of continuous improvement and development.