temperature operational temperature
DESCRIPTION
Temperature Operational temperature. Design temperature. t Tp,max. System supply t 1. t w1. Systém return t 2. t w2. t w. Emitter supply t w1. t 1. Emitter return t w2. Mean emitter temperature tw. t 2. Maximal emitter surface temperature t Tp max. - PowerPoint PPT PresentationTRANSCRIPT
Expansion vessel
Heat emmiter
Boilerl
H
T 1 , 1
T 2 , 2 Supply
Return
Expansion vessel
Heat emmiter
Boilerl
H
T 1 , 1
T 2 , 2 Supply
Return
Temperature Temperature Operational temperatureOperational temperature
Design temperature
t2
t1
tw1
tw2
tTp,max
tw
Temperature difference - emitter = tw1 - tw2
Temperature difference system = t1 - t2
System supply t1
Systém return t2
Emitter supply tw1
Emitter return tw2
Maximal emitter surface temperature tTp max
Mean emitter temperature tw
Expansion vessel
Heat emmiter
Boilerl
H
T 1 , 1
T 2 , 2 Supply
Return
Expansion vessel
Heat emmiter
Boilerl
H
T 1 , 1
T 2 , 2 Supply
Return
Temperature in the Temperature in the system system
Heat Heat transferred by transferred by the systemthe system
Heat Heat transferred by transferred by the emitterthe emitter
21 ttcMQ
iwt ttAhQ t2
t1
tw1
tw2
tp1,max
tw
Temperatures Temperatures Design Criterions Design Criterions
Economical criterions
Physical properties of the medium
Hygiene requirements
Technical properties of the heat source
TemperatureTemperatureParameters designParameters design
Heating system supply temperatureHeating system supply temperature Low- temperature t1
<=65°C Medium - temperature 65°C< t1 <=
115°C High temperature t1 > 115°C
Temperature difference Temperature difference – 10K - 25K, high temperature 40K - 50K. – 90/70 °C, 80/60°C, 75/55°C, 55/45°C
Temperature Parameters Temperature Parameters DesignDesign
Emitter Emitter – Maximal surface temperature (85 - Maximal surface temperature (85 -
90°C)90°C)
– Temperature differenceTemperature difference Two-pipe = systTwo-pipe = systeem temperature difference m temperature difference
(15 - 25 K) (15 - 25 K) one-pipe < systone-pipe < systeem temperature difference m temperature difference
OS (5 - 10 K) OS (5 - 10 K)
5,21max wTp tt
Piping materialsPiping materials
– The material should be selected at The material should be selected at the beginning of the design processthe beginning of the design process
– Used materialsUsed materials steelsteel coppercopper plasticplastic
Piping materialsPiping materialsSteelSteel
Traditional materialTraditional material WeldingWelding
Piping materialPiping materialCopperCopper
Lower material usageLower material usage Chemical reaction with water pH Chemical reaction with water pH
min7min7 Electrochemical corrosion (Al)Electrochemical corrosion (Al) solderingsoldering , , torch brazingtorch brazing
Piping materialPiping materialPlasticPlastic
MaterialsMaterials Netted polyethylene (PEX, VPE), polybuten (polybutylen, polybuten-1,PB), polypropylen (PP-R, PP-RC,PP-3), Chlorided PVC (C-PVC, PVC-C) Multilayer pipes with metal
Life-cycle !!!Life-cycle !!! Oxygen barierre ?Oxygen barierre ?
Heating system hydraulic Heating system hydraulic calculationcalculation
CalculationCalculation
Temp difference Temp difference setupsetup
Transferred outputTransferred output Circulation modeCirculation mode HydraulicHydraulic sch scheemmee, ,
sectionssections, , circuitscircuits Water flow rateWater flow rate
Design of the pipe Design of the pipe diameterdiameter
Forced circulationForced circulation– metmethhod od eecconomiconomical specific pressure al specific pressure
loss loss 60 60 -- 200 Pa.m 200 Pa.m-1-1
– metmethhod od optimal velocityoptimal velocity 0,05 0,05 -- 1,0 m.s 1,0 m.s-1-1 (!!! (!!! NoiseNoise))
– metmethod hod given pressure differencegiven pressure difference buoyancybuoyancy + pump head+ pump head 10-70 kPa 10-70 kPa
Natural circulationNatural circulation– metmethod hod given pressure differencegiven pressure difference
buoyancybuoyancy
Pressure loss calculationPressure loss calculation Pressure lossPressure loss
– frictionfriction– Local resistanceLocal resistance
Pressure loss of the circuit Pressure loss of the circuit compare with the pump headcompare with the pump head
Pressure excess Pressure excess is reduced by the is reduced by the control valvescontrol valves
Pressure lack – Pressure lack – must be changed must be changed the pump or the pump or redesigned the redesigned the systemsystem