Transcription
CHAPTER 8CENTRAL HEATINGProf. Dr. Uğur Atikol
Central Heating A central-heating system provides warmth to the wholeinterior of a building (or portion of a building) from onepoint to multiple rooms. Central heating can be achieved by Combustion of fosil fuel by a furnace (boiler) Air-to-air heat pump system Air-to-water heat pumpsystem70oCBoiler90oC Water-to-water heat pump system Solar thermal systems. Heat is distributed by Water circulating through pipes Forced air through ductwork Steam circulating through pipesRoom 4Room 3Room 1Room 2Hot water centralheating system
Components Boilers (or heat pumps) Solar collectors Heat distribution pipes or headersHot water tanksUnderfloor pipesRadiatorsTowel railsFan convectors(Source: orks.aspx)
One-pipe Central Heating SystemRadiator thermostatRoom thermostat
Two-pipe Central Heating SystemCentral Heating with BoilersCentralheatingBoilerEfficiency 0.83 – 0.95To radiotors, fanconvectors or floorheatingReturn pipeFuelFlow pipePumpBurner
Two-pipe Central Heating SystemHydro-flow (or water circulation) Heating SystemsCombi-boilerRadiatorsShowerTwo-pipe systemWith flow and return pipes.
A Modern Central Heating ow-it-works.aspx)
How Does a Boiler Work?Cast iron blockFLAMEBurnerCan be gas oroil fired
Installation of RadiatorsRadiators and Towel RailsCorridorBedroomBathroom
Installation of RadiatorsWhy place them under the windows?Radiator placed on an interior wallRadiator placed under the windowSource: diator-heat-the-room/
Underfloor HeatingA cutaway of underfloor heating arrangementFloor finishPipeworkScreedThermal insulationSlab
Underfloor Heating vs Radiator HeatingRadiator heatingUnderfloor heatingSource: comfort/
Underfloor Heating vs Radiator HeatingRadiator HeatingUnderfloor Heating
Heat PumpsRefrigeration ://www.samsainc.com/refrigeration.html)Outdoor unitIndoor unit(http://www.descoenergy.com/system type.htm)Coefficient of Performance 3 – 5(in warm climates)
Ducted PackagedSystems or Rooftop Units
Rooftop Unit with Fresh AirRooftop unitFresh airMixingchamberRoofA/CSupplyairReturn airConditionedBuildingRoofExhaustair
Heat Recovery VentilationHeat recovery ventilation for Energy Efficiency in Winter5oCIndoors20oC8oCOutdoors17oC(Source: http://omega-bud.pl/main.php?l en&p l)
Heat is absorbedby the refrigerantleading to itsevaporationCooledairAir-to-Air Split System Heat PumpHeatHeatHeatHeatfrom airRefrigerant releases its heat and condensesElectricity tocompressor
Ducted Split-Unit Heat Pump SystemsDuctingOutdoor unitIndoor unitSupplygrilles
Air-to-Water Heat PumpsEvaporator coilsCoolairWarmairCondenser coilsThe achieved water temperatures are mostappropriate for underfloor heating
Variable Speed Drive (VSD) in DuctedSystemsAir ductFanMotorAir flowPressuresensorVSDElectricity inputFeedback signal issent to VSD toincrease or decreasethe speed of motor
Variable Speed Drive (VSD) Because of the fan laws, large savings canbe achieved using variable speed drives forfans and pumps. The cube law says:kWnew [RPM new ] 3kWold [RPM old ]3 VSD can be applied to all electric motors(where ever they are available in a system)in order to achieve energy efficiency.Fans, pumps,compressors etc.
Air-to-air heat pump system Air-to-water heat pumpsystem Water-to-water heat pump system Solar thermal systems. Heat is distributed by Water circulating through pipes Forced air through ductwork Steam circulating through pipes Boiler Room 1 . Room 3 . Room 2 Room 4 70 o C . 90. o. C . Hot water central heating system
