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FLOOR HEATING ++Lecture 2c
• Bjarne W. Olesen, Ph.D.
• Professor,
• International Center for Indoor Environment and Energy
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RadiantRadiant surfacesurface heatingheatingand and coolingcooling systemssystems
FloorFloor WallWall
Thermo Active Building SystemsThermo Active Building Systems
CeilingCeiling
ReinforcementReinforcement
FloorFloor
ConcreteConcrete PipesPipes
RoomRoom
RoomRoom
WindowWindow
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Determination of Heating and Cooling Capacity
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STANDARDS• prEN 1264-2, 2007: Prove methods for the determination of the thermal
output of floor eating systems using calculation and test methods– EN 1264-1, 1999: Floor heating: Systems and components - Part 1 :
Definitions and symbols – EN 1264-3, 1999: Floor heating: Systems and components - Part 3 :
Dimensioning – EN 1264-4, 2001: Floor heating: Systems and components - Part 4:
Installation • prEN 1264-5, 2007: Heating and cooling surfaces embedded in floors,
ceilings and walls — Determination of thermal output and cooling output
• EN15377-1, 2007: Embedded water based surface heating and cooling systems: Determination of the design heating and cooling capacity
• EN15377-2, 2007: Embedded water based surface heating and cooling systems: Design, Dimensioning and Installation
• EN15377-3, 2007: Embedded water based surface heating and cooling systems: Optimizing for use of renewable energy sources
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SURFACE HEATING AND COOLING
Heat transfer coefficient
8,08,0
6,0
11,011,0
7,0
5,5
6,5
7,5
8,5
9,5
10,5
11,5
Floor
Ceiling
Wall
W/m2K
HeatingCooling
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Floor heating and Ceiling cooling: q = 8,92 (θS,m - θi)1,1
Wall heating and Wall cooling: q = 8 ( θS,m - θi )
Ceiling heating: q = 6 ( θS,m - θi )
Floor cooling q = 7 ( θS,m - θi )
Where q is the heat flux in W/m2θS,m is average surface temperature θi is room design temperature (operative)
SURFACE HEATING AND COOLING
Heat transfer coefficient
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SURFACE HEATING AND COOLING
Max. - Min. Surface temperature
40
17
27
17
35
20
29
20
15
20
25
30
35
40
45
Floor
CeilingWall
oC
HeatingCooling
Perimeter
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MAXIMUM HEATING AND COOLING CAPACITY
160
72
42
99
165
42
99
42
020406080100120140160180200
Floor
CeilingWall
HeatingCooling
Perimeter
W/m2
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• CALCULATION OF THE HEAT OUTPUT W/m²
• System factor B will depend on type of system and type of pipe
Universal single power function (EN1264)
FLOOR HEATING
System constant~ 6.5 - 6.7 Temperature difference(Room - water)
Factors
B a a a a tB Tm
Dm
um
wT D u
Floor covering Pipe spacing Pipe diameter Screed covering
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HEATING CAPACITY
• Floor covering aB, spacing aT, and covering aD factors in tables
• mT = 1- T/0.075 (T = Pipe spacing, m)
• mu = 100 ( 0.045 - su ) (su = covering thickness, m)
• mD= 250 ( D-0.020 ) (D = Pipe diameter, m )
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Table A.1 : Floor covering factor aB depending on the thermal resistance R,B of the floor coveringand the thermal conductivityE of the screed for type A and C systems
R,B(m2K/W) 0 0,05 0,10 0,15
E(W/(m.K)) aB
2,0 1,196 0,833 0,640 0,519
1,5 1,122 0,797 0,618 0,505
1,2 1,058 0,764 0,598 0,491
1,0 1,000 0,734 0,579 0,478
0,8 0,924 0,692 0,553 0,460
0,6 0,821 0,632 0,514 0,433
NOTE : The floor covering factor aB may be determined withthe following equation:
a
s
sR
B
u,0
u
u
EB
1
10
0
,
,,
where = 10,8 W/m2K;u,0 = 1 W/m.K; su,0 = 0,045 m
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HEATING CAPACITY
m2K/W
FACTOR FOR FLOOR COVERING, aB
Screed0.80
1.20
00.050.10.15
0.490.46
0.60
0.55
0.76
0.69
1.06
0.92
0.00
0.50
1.00
1.50
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COOLING CAPACITY
• Total factor for the following example• 17 mm pipe
• 45 mm concrete above pipes
• Concrete ~ 1,2 W/mK
75150
300
0,01
0,1
0,52
0,77
0,96
0,420,57 0,66
0
0,2
0,4
0,6
0,8
1
T, mm
Rb, m2K/W
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COOLING CAPACITY
• Cooling capacity in W/m²for the following example• 17 mm PEX-pipe
• 45 mm concrete above pipes
• Concrete ~ 1,2 W/mK
• Space temperature 26 °C
• Supply water temperature 14 °C
• Return water temperature 19 °C
75150
300
0,01
0,1
25
37
46
2027
32
0
10
20
30
40
50
W/m2
T mm
Rb m2K/W
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ALUMINUM HC device: Floor Heating & Cooling (type B), R=0.01~0.1, T=150 & 300
0
20
40
60
80
100
120
140
160
-15 -10 -5 0 5 10 15 20 25 30
Heating/cooling medium differential temperature ΔθH=θH-θi [°C]
He
at e
xc
ha
ng
e [
W/m
2]
T=150, R=0.01
T=150, R=0.1
T=300, R=0.01
T=300, R=0.1
Figure 4.17 Heat exchange between the surface (with ceramic tiles, wooden
parquets or carpet R?B=0.1 and no covering R?B=0) and the space when aluminium heat conductive device used
Heating/ cooling capacity, EN1264 and EN 15377
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Thermal resistance methods
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Pipes embedded in a massive concrete layer
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s1
s2
v
R2
Rt
R1
q1
q2
c
Thermal resistance method
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Capillar tubes
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c
v Rt
R1
R2
s2
Thermal resistancemethods
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Thermal resistance method
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Thermal resistance method
Ri
Re
RHC
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Thermal resistancemethods
Total thermal resistance between the heat source and the conducting layer
m² °C/W
CLUcon,RRHC RRT
RTRTR 2
W/m²
HHi ΔθKq
is the differential temperature of the heating/cooling medium
KH
H H i
equivalent coefficient of thermal conductivity
W/m²C
)/(1 iHCH RRK
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Finite Element Method
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Laboratory testing
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UNIFORMITY OF FLOOR SURFACE TEMPERATURE
Maximum
Minimum
Mean
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RADIANT FLOOR COOLING
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COOLING CAPACITY
107
129
148
15
35
55
75
95
115
135
155
25 20 15
W/2m
CALCULATED CAPACITY IN AN ATRIUMWITH DIRECT SUNSHINE ON THE FLOOR
Supply water temperature, oC
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ALUMINUM HC device: Floor Heating & Cooling (type B), R=0.01~0.1, T=150 & 300
0
20
40
60
80
100
120
140
160
-15 -10 -5 0 5 10 15 20 25 30
Heating/cooling medium differential temperature ΔθH=θH-θi [°C]
He
at e
xc
ha
ng
e [
W/m
2]
T=150, R=0.01
T=150, R=0.1
T=300, R=0.01
T=300, R=0.1
Figure 4.17 Heat exchange between the surface (with ceramic tiles, wooden
parquets or carpet R?B=0.1 and no covering R?B=0) and the space when aluminium heat conductive device used
Heating/ cooling capacity, EN1264 and EN 15377
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Hea
t su
pp
ly
Flo
o rsu
rfac
ete
mp
erat
ure
Flo
o rco
v eri
ng
Pipe distance
Twater-average – troom
Diagram for
17x2 mm pipe
45 mm screed
= 1,2 W/mK
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Wa t
er f
l ow
rat
e
Pressure drop
Water
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The design supply water temperature is determined
according to the room with the highest heat load or with the highest heat resistance of the floor covering.
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Calculation of the water supply temperature
Heat resistance of the floor covering R,B = 0,15 m2K/WPipe spacing 15 cmDesign heat loss 80 W/m2
From the dimensioning diagramDifference between average water temperature and room:
H = 28,9 K
Average water temperature:HM= 20°C + 28,9 K = 48,9 °C
Temperature difference (supply-return) for the critical room: EN1264 = 5 K
Design supply water temperature:
Vdim = HM + /2 = 48,9°C +2,5 K = 51,4 °C
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H = 28,9°C
HM = 48,9 °C
Vausl = 51,4 °C
80 W/m2
0,15m2K/W
FB= 27,3 °C
Boundaryconditions
Så = 45 mm å = 1,2 W/mK
Diagram fordimensioning
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DIMENSIONING AND DESIGN
• Pipe diameter
• Pipe spacing
• Pipe layout
• Water flow rate
• Pipe circuits
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RL
VL
Kombizone
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RLVLRLVL
Perimeter and occupied space
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RLVL
Occupied space
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Cover as much surface as possible
Possible solution
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VLRL
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RL
VL
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Joints in the concrete
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Example
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Floor area
Korrektur afNormvarmetabet
Største varmestrøm
Bad tages ikke med
Correction for coveredsurface
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Tilslutningsledninger
Total rørlængde
egen varmekreds
gennemgående
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Forbindelses rör
9
10
11
12
13
14
15
45 46 47 48 49 50 51 52 53 54 55 56 57 58
Dimensionerende fremlöbstemperatur [°C]
Var
mea
fgiv
else
[W
/m]
45 mm Beton, Ü = 1,2 W/mK
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Vandstrøm:
RFRFr TTTTc
q
86,0
qr: Vandstrøm l/h
c: Vands varmefylde Wh/kgC
Φ: Varmeydelse W
Water flow
Water flow
Specific heat capacity
Heat supply
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Tryktabsdiagramdiagramfor 17 x 2 mm rør
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Pressure drop 14 x 2 mm pipe
Pressure drop
WaterWat
er f
low
rat
e
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Valveposition
5 1/4
14
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Valve position
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INSTALLATION
• Floor systems
• Wall systems
• Ceiling systems
• TABS Thermo Active Building Systems
• Pre-fabrication
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1. Screed-concrete 2. Pipe3. Plastic foil4. Insulation 5. Acoustic insulation6. PE foil7. covering 8. Concrete slab
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RadiantRadiant surfacesurface heatingheatingand and coolingcooling systemssystems
FloorFloor WallWall
Thermo Active Building SystemsThermo Active Building Systems
CeilingCeiling
ReinforcementReinforcement
FloorFloor
ConcreteConcrete PipesPipes
RoomRoom
RoomRoom
WindowWindow
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Calculation methods
1. Rough sizing method based on a standard calculation of the cooling load (accuracy 20-30%). To be used based on the knowledge of the peakvalue for heat gains (section 5.1)
2. Simplified method using diagrams for sizingbased on 24 hours values of heat gains (accuracy15-20%, section 5.2).
3. Simplified model based on finite difference method (accuracy 10-15%). Detailed dynamic
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