Daikin DPS005 Installation And Maintenance Manual

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Daikin DPS005 Installation And Maintenance Manual Manual pdf 66 page image

opTIonal energy reCovery WheelSystem DescriptionWhen a unit is equipped with an optional enthalpy wheel, energyrecovery is provided by drawing outside air across half of theenthalpy wheel and drawing exhaust air across the other half.Latent heat and sensible heat are transferred from the hotterand moist exhaust air to the colder and dry outside air duringwinter conditions. Latent heat and sensible heat are transferredfrom the hotter and moist outside air to the cooler and dryexhaust air during summer conditions. Energy recovery controlconsists of starting and stopping an exhaust fan, modulatingthe speed of the exhaust fan, starting and stopping an enthalpywheel, optionally controlling the speed of the enthalpy wheeland opening and closing a set of bypass dampers. The outdoordampers are controlled in the normal manner.DefinitionsThe following are descriptions of various components relatedto the enthalpy wheel construction (Figure 60):Bearing, external - The wheel and bearing rotate on the shaft,no field lubrication is required.Brush seal - The seal used for both the circumferential sealand the inner seal in the cassettes. They are constructed ofnylon brush and configured to seal against the enthalpy wheelband in the case of the circumferential seal, and against thewheel face in the case of the inner seal. These seals are fullcontact seals, have an integral clip, and they are clipped to thecassette face panel cutout (circumferential) or to the (inner)postCassette - The steel structure that houses the rotor. Cassettesare of punched sheet metal panel construction.Enthalpy wheel - A generic name for an energy conservationwheel. The term “enthalpy” refers to an air stream’s totalenergy (temperature and humidity level).Exhaust air - The air stream that is exhausted to the outside.Exhaust air is building return air that has been run through theenthalpy wheel.Heat wheel - Synonymous with an enthalpy wheel, energyconservation wheel, or total energy recovery wheel. Some heatwheels are sensible only wheels and should not be confusedwith Daikin total energy recovery wheels.Hub - The center support of an enthalpy wheel.Latent energy - Latent energy, in the context of enthalpy wheeldiscussions, is the work done by the wheel to transfer moisturefrom one air stream to another. Latent work is accompanied byhumidity changes in the air streams.Media - The chemical composite part of the enthalpy wheelwhich actually performs the latent and sensible exchange.Outdoor air - The air stream that is brought in from the outside.Outdoor air becomes supply air after going through the enthalpywheel.Purge - A small segment of supply air defined by the gapbetween the inner seal on the outdoor air edge of the centerpost and the supply air edge of the center post. The purge angleis adjustable. The purge captures the small amount of supply aircaptive in the enthalpy wheel when the wheel moves from returnto supply and routes it to return to minimize cross contamination.Return air - The air stream that is returned from the building.Return air becomes exhaust air after going through the enthalpywheel.Rotor - The part of an enthalpy wheel that performs the energyexchange and consists of the wheel media, hub, spokes andbandSensible heat - Sensible energy, in the context of enthalpywheel discussion, is the work done by the enthalpy wheel totransfer heat from one air stream to another. Sensible work isaccompanied by temperature changes in the air stream.Supply air - The air stream that is supplied to the buildingspace. Supply air is outdoor air that has been run through theenthalpy wheel.ArrangementsTwo arrangements are offered for the enthalpy wheel:1 Single enthalpy wheel with economizer and bypass(Figure 60). This arrangement is available for all units.2 Single enthalpy wheel without economizer (100%outdoor air unit).Wheel ConstructionYour Daikin enthalpy wheel is delivered completely assembledand ready to run. The wheel is built to provide many years oftrouble free service following proper installation and performanceof the minimal maintenance requirements.IM 1125-7 • REBEL ROOFTOPS 66 www.DaikinApplied.comopTIonal energy reCovery Wheel