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8 STEPS - CONTROL OF HEATING SYSTEMS
CHAPTER 8 TECHNICAL DATA, FORMULAS AND CHARTS
161
TECHNICAL DATA, FORMULAS AND CHARTS
Diagram for local district heating plants and heating and power plant . . . . . . . . . . . . . . .162
Diagram for heating and domestic hot and cold water . . . . . . . . . . . . . . . . . . . . . . . . . . .163
Heat emission from radiators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164
Conversion chart for radiators in one-pipe systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165
Reduction of heat emission from radiators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .166
Heat losses from uninsulated pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .167
Pressure drops in steel pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168
Resistance in heating systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
Sizes of steel pipes for heating systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
Flow chart for thermostatic radiator valves in one-pipe system . . . . . . . . . . . . . . . . . . . . .170
Flow chart for thermostatic radiator valves in two pipe system . . . . . . . . . . . . . . . . . . . . .171
Flow chart for p control valves for risers or circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .172
Flow chart for control valves in heating systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173
Flow chart for control valves in district heating systems . . . . . . . . . . . . . . . . . . . . . . . . . . .174
Flow chart for p control valves in district heating systems . . . . . . . . . . . . . . . . . . . . . . . .175
Heat requirements for domestic hot water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177
Flow limiters for one-pipe circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .178
Calculation of one-pipe systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .180
Calculation of two-pipe systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182
SI-units, Greek alphabet, Physical properties for water . . . . . . . . . . . . . . . . . . . . . . . . . . . .184
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162 8 STEPS - CONTROL OF HEATING SYSTEMS
130 C
70 C
130 C
130 C
70 C
70 C
130 C
130 C
70 C
70 C
130 C
130 C
70 C
70 C
Diagram for local district heating plants connected to a heating and power plant.
Heating andpower plant
Local heating plant
Flue gascooler
Safetyvalve
Exp. tank
Boiler
Safetyvalve
Heat exchanger
Accumulator
Heat meter
Flue gascooler
Safetyvalve
Exp. tank
Boiler
Safetyvalve
Heat exchanger
Accumulator
Heat meter
Flue gascooler
Safetyvalve
Exp. tankBoiler
Safetyvalve
Heat exchanger
Accumulator
Heat meter
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CHAPTER 8 TECHNICAL DATA, FORMULAS AND CHARTS
163
6
120-70 C
90 C65 C
Diagram for heating and domestic hot and cold water.
Expansion tank
p - control
Flow meter
Domestic hot water
Domestic cold water
Flowmeter> 6 storeys
Heat meterDomestic hot water 60
Domestic cold waterCirculation
Control valve< 6 storeys
Storeys
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40 30 25 20 16
0
1,0
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
1,1
1,2
0 1,0 2,0
90
60
70
80
50
0,5 1,5 2,5
1
2
4
5
6
3
164 8 STEPS - CONTROL OF HEATING SYSTEMS
CHAPTER 8 TECHNICAL DATA, FORMULAS AND CHARTS
Heat emission from radiators.
Two-pipe system with thermostaticvalves.Measured 1 : tflow 75 oC, t 8 oCHeat requirement : 0,83, Q = 2,47
tflow 80o
C : 2 t 16o
C, Q = 1,23Every point along the horizontal line0,83 gives the same heat emission.
The influence of gravity forces on heat emission from a radiator in a two-pipe systemFor a correctly sized radiator 3 ( with manual radiator valve in a two-pipesystem ) the heat emission will increases only by 5% when the flowincreases by 23%, 4 , depending on gravity forces. The temperature dropacross the radiator however will decrease by 5 oC and that is significant,because it reduces the capacity of the whole system all the way down tothe heating and power plant.
Resuls t for one- and two - pipe circuits, and required pump capacitywhen thermostatic valves utilize internal and external heat gains.
Two-pipe circuit One-pipe circuitPoint Heat Flow t Circuit resi- Pump ca- Flow t Pump ca-
gain % % oC stance % pacity % % oC pacity %
3 0 100 25 100 100 100 25 100
5 10 66 33 44 29 100 22,5 100
6 20 47 39 22 10 100 20 100
n = 1,3 troom = 20 oC tflow = 90 oC t = 25 oC
t oC
Heat
emission
Q
12
10
8
6
5
4
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0,8
0,9
1,0
1,1
1,2
1,3
1,4
1,5
1,6
1,7
1,8
1,9
2,0
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
90
85
80
75
70
60 65
21
Conversion chart for radiators in one-pipe circuits.
Conversion chart for panel and section radiators in one-pipe circuits.Enter the current tflow and temperature drop and find the conver-
sion factor, Fc.
Multiply the heat requirement by Fc and select size of the radiator
according to the new value.
Example.Calculated heat requirement: 1.230 W.
tflow : 82oC, t: 15 oC, 1
Fc = 1,16 2Converted heat requirement: 1.230 x 1,16 = 1.427 W.
Formula for calculating Fc:
49,33 x ln
t1 - t2[ ]t1 - tr n
t2 - tr( )n
Panel radiator 1,28Section radiator 1,29Convector 1,3 - 1,33
F =
tflow oCFc
to
C
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a
The control unit has to sense the room temperature to be able to control it.
No enclosure0%
Shelf withopening0%
Shelf close tothe wall10 -2%
Open frontedrecess with ashelf12 -6%
Encased withgrille in front> -15%
Encased withsmall grille infront. Notrecommended.> -30%
Acceptablecabinet. -8 - 10%
Reduction of heat emission from radiators fixed in some type of enclosure
Radiation from a radiator depending on the treatment of thesurface.
Material Surface treatment Radiation %
Steel, cast iron 100
Oil paint 100
Aluminium orcopper bronzes 75
Zinc white 101
Lead white 99
Enamelled White 101
Matt green 96
Aluminium 8
10 - 100 mm 30 - 100 mmAlternativeopenings a+40
>
100mm
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0
100
200
300
400
0
20 40 60 80 100 120
80/89 65/76
50/6
40
32
25
20
1015
CHAPTER 8 TECHNICAL DATA, FORMULAS AND CHARTS
8 STEPS - CONTROL OF HEATING SYSTEMS
Heat losses from uninsulated horizontal pipe.
For vertical pipe reduce by 20%
One-pipe above another reduce by 12%
Three pipes above each other reduce by 20%
Temperature above room temperature oC
Heat emissionW/m pipe DN/0
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5 7 10 20 30 mmWG/m
,05 ,07 0,1 0,2 0,3 0,4 0,5
kPa/m
25
15
20
32
40
80
50
100
125
150
,01,015
,02
,03
,04,05
,07
,1
,15
,2
,3
,5
,4
,7
1
1,5
2
3
457
10
4050
15
20
30
1,0
2,0
10
100
1000
10
100
1,5
2
3
45
7
15
20
30
4050
70
150
200
150
200
300
400500
700
70
5040
15 40 50
0,15
65
3,0
m/s0,
2
0,3
0,4
0,5
k = 0,00003 m
Density = 1.000 kg/m3
Pressure drop in steel pipes for heating installations.
m3/h DN mm l/s
l/h
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0,1
0,20,30,5
1,02
3
,01 ,02 ,03 ,05 0,1 ,2 ,3 ,5 1
1
2
64
3
2 3 4 5 107
169
CHAPTER 8 TECHNICAL DATA, FORMULAS AND CHARTS
8 STEPS - CONTROL OF HEATING SYSTEMS
p for values at differnt rates.Symbol Units Coefficient of resistance,
Branch tee 1
Through tee 1
Elbow, smooth 0,2
Bend 1
The values for the coefficient of resis-tance for tees, elbows and bends.
The pressure drop is calculated from:p = 0,5 2 ,
Recommended portion of pipe losses for different systems or part ofsystems.
Type of system Unit Friction %
Heating Small buildings 50 - 60
Large buildings 60 - 70
Sub-stations Primary and secondary side 20 - 30
Distribution pipe net work Primary side 80 - 90
valuem/s
p kPa
Sizes of steel pipes for heating systems. Working pressure 1,0 MPa (10 bar)Nominal diameter External diameter Wall thickness Internal diameter
mm inch mm mm mm8 1/4 13,50 2,25 910 3/8 17,00 2,25 12,515 1/2 21,25 2,75 15,7520 3/4 26,75 2,75 21,2525 1 33,50 3,25 27,0032 1 1/4 42,25 3,25 35,7540 1 1/2 48,00 3,50 41,0050 2 60,00 3,50 53,0065 2 1/2 75,50 3,75 68,0080 3 88,50 4,00 80,50100 4 114,00 4,00 106,00125 5 140,00 4,50 131,00150 6 165,00 4,50 156,00
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30
5070100
200
300
5007001000
0,1 ,2 ,3 ,4 ,5 ,7 1,0 2 3 kPa
0,01 ,02 ,03 ,07 ,1 ,2 ,3 mWG
,001 ,002 ,004,006 0,01 ,02 ,03 Bar
,01
,02
,03
,05,07,1
,2
,3
,05
4 5 7 10 20
,7 1 2
,04 ,06 0,1 ,2
,5
15
2025
170 8 STEPS - CONTROL OF HEATING SYSTEMS
CHAPTER 8 TECHNICAL DATA, FORMULAS AND CHARTS
Flow chart for RTD-G 15, 20 and 25
RTD - G 15, 20 and 25
l/h l/sValve size
pvalve
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3
5710
20
30
5070100
,001
,002
,003,005
,007,01
,02
,03
1 2 3 4 5 7 10 20 30 kPa
0,1 0,2 ,3 ,4 ,5 ,7 1 2 3 mWG
0,01 ,02 ,04 ,06 0,1 ,2 ,3 Bar
,1
,05,07
500
300
200N
1
23
45
67
3
5710
20
30
5070100
,001
,002
,003
,005,007,01
,02
,03
1 2 3 4 5 7 10 20 30 kPa
0,1 0,2 ,3 ,4 ,5 ,7 1 2 3 mWG
0,01 ,02 ,04 ,06 0,1 ,2 ,3 Bar
,1
,05,07
500
300
200
N
1
23
456
7
Flow chart for thermostatic valves in two-pipe system
l/hl/sPre-set value
pvalve
Pre-set value 1 2 3 4 5 6 7 N
kv values 0,04 0,08 0,12 0,20 0,27 0,36 0,45 0,60
Pre-set value 1 2 3 4 5 6 7 N
kv values 0,10 0,15 0,17 0,25 0,32 0,41 0,62 0,83
l/hl/sPre-set value
pvalve
RTD - N 15
RTD - N 20 - 25
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0,1
0,2
0,3
0,5
0,71,0
23
5710
0,1
0,2
0,3
0,50,7
1,0
2
3
,03
,05,07
1 2 3 4 5 7 10 20 30 40 60 80 kPa
0,1 0,2 ,3 ,4 ,5 ,7 1 2 3 4 5 7 mWG
0,01 ,02 ,04 ,06 0,1 ,2 ,3 ,4 ,5 ,7 Bar
520
8
,8
1,62,54,06,3
10
1
Flow chart for p control valves for riser or circuit in heating systems.
ASV-P, PV 15-40 and ASV-M 15-40
m3/h l/skvs-value
pvalve
Working range:
ASV-P 10 kPa
ASV-PV 5 - 25 kPa.
Minimum available p for good functioning: 8 kPa.
Example
Q: 300 l/h. p riser: 7kPa. p radiator including valve: 5 kPa.p-control kv 1,6. pvp = 3,4 kPa, 1Necessary p = 7+5+8 = 20 kPa.
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0,1
0,2
0,3
0,50,71,0
23
5710
0,1
0,2
0,3
0,50,71,0
23
,03
,05,07
1 2 3 4 5 7 10 20 30 40 60 100 200 kPa
0,1 0,2 ,3 ,4 ,5 ,7 1 2 3 4 5 7 10 15 20 mWG
0,01 ,02 ,04 ,06 0,1 ,2 ,3 ,4 ,5 ,7 1,0 1,5 2 Bar
10
5
7
150
50
30
20
100
200
20
30
50
,4
,631,0
1,62,54,06,3
1016
25
40
6310014
5
Flow chart for control valves in heating systems.
m3/h l/skvs-value
pvalve
Formulas.
p : bar. Q: m3/h. kv = ; p = ; Q = kv p ;Q
pQ
kv( )2
p : kPa. Q: l/h. kv = 0,01 ; p = 0,01 ; Q = 100x kv p ;Q
pQ
kv( )2
p : kPa. Q: l/s. kv = 36 ; p = 36 ; Q = p ;Q
pQ
kv( )2 kv
36
Q
Q
Q
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0,1
0,2
0,3
0,50,71,0
23
5710
0,1
0,2
0,3
0,50,71,0
23
,03
,05,07
1 2 3 4 5 7 10 20 30 40 60 100 200 kPa
0,1 0,2 ,3 ,4 ,5 ,7 1 2 3 4 5 7 10 15 20 mWG
0,01 ,02 ,04 ,06 0,1 ,2 ,3 ,4 ,5 ,7 1,0 1,5 2 Bar
10
57
150
50
30
20
100
200
20
30
50
,4
,631,0
1,62,54,06,310
16
25
40
6310014
5
Flow chart for valves in district heating systems.
m3/h l/skvs-value
p
valve
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0,1
0,2
0,3
0,5
0,71,0
23
5710
0,1
0,2
0,3
0,50,7
1,0
2
3
,03
,05,07
1 2 3 4 5 7 10 20 30 40 60 80 kPa
0,1 0,2 ,3 ,4 ,5 ,7 1 2 3 4 5 7 mWG
0,01 ,02 ,04 ,06 0,1 ,2 ,3 ,4 ,5 ,7 Bar
520
8
,8
1,62,54,06,3
10
1
m3/h l/skvs-value
pvalve
AVP 15 - 32
Flow chart for p control valves in district heating systems.
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0,1
0,2
0,3
0,50,71,0
23
57
10
0,1
0,2
0,3
0,50,71,0
2
3
,03
,05,07
1 2 3 4 5 7 10 20 30 40 60 100 200 kPa
0,1 0,2 ,3 ,4 ,5 ,7 1 2 3 4 5 7 10 15 20 mWG
0,01 ,02 ,04 ,06 0,1 ,2 ,3 ,4 ,5 ,7 1,0 1,5 2 Bar
10
57
150
5030
20
100
200
2030
50
,631,0
1,62,54,06,3
10
16
25
50
80125
20
Flow chart for p control valves in district heating systems.
m3/h l/skvs-value
pvalve
IVD-IVFS kvs 0,63 - 25,0 m3/h
AFP kvs 50 - 125 m3/h
p-regulator, working range: IVD 5 - 50 and 20 - 250 kPa.AFP 20 - 120 and 50 - 250 kPa
Maximum p valve IVF kvs: 0,63 and 1,0 = 1.000 kPa2,5 = 630 kPa4,0 - 25 = 800 kPa
Maximum p valve AFP: 1.200 kPa
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0
0,5
1,0
1,5
2,0
2,5
050100150
200250300
350
400
1 10 50 100 150 200 250
Heat requirement for hot water according to the Swedish Board of District Heating
Domestic hot water, Q L/s. Effect, P kW
Number of apartments.
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0,07
0,1
0,15
0,2
0,3
0,4
0,5
0,6
0,7
0,8
1,00,9
20 30 40 50 60 70 80m /h
3p kPav
0,2 0,3 0,4 0,5 0,6 0,7 0,8
p Barv
1
2
3
4
5
8
6,5
0,2
0,3
0,4
0,5
0,7
2,0
1,5
1,00,90,8
0,6
20 30 40 50 60 70 80m /h
3p kPav
0,2 0,3 0,4 0,5 0,6 0,7 0,8
p Barv
10
1214
2
4
6
8
Flow limiter, ASV-Q 15, Flow limiter, ASV-Q 20
Set values
Set values
ASV-Q Capacity l/h Set value
15 100 - 800 1 - 820 200 - 1400 2 - 1425 400 - 1600 4 - 1632 500 - 2500 5 - 30
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2,0
1,7
1,5
1,2
1,00,90,8
0,7
0,6
0,5
0,4
30 40 50 60 70 80m /h
3p kPav
0,3 0,4 0,5 0,6 0,7 0,8
p Barv
10
12
14
16
4
6
8
4,0
3,0
2,0
1,5
1,2
1,00,90,80,7
0,6
0,5
0,4
m /h3
30 40 50 60 70 80p kPav
0,3 0,4 0,5 0,6 0,7 0,8
p Barv
5
15
10
20
25
30
Flow limiter, ASV-Q 25, Flow limiter, ASV-Q 32
Set values
Set values
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Calculation of one-pipe system
6
31 m
6 m6 m6 m6 m
1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1200
1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1200
1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1200
1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1200
6 m 6 m 6 m
1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1200
1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1200
1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1200
1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1200
3x12=
36m
1,5 m
0
2345
2345
6
789
1
10
10 m
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Calculation of one-pipe system
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Calculation of two-pipe system
12001200 1200 120012001200 1200 1200
1200 12001200 12001200 12001200 1200
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
3 m 6 m 6 m 6 m
12345
6
7
8
9
10
11
12
13
14
15
16
17
3m
3m
31 m
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Calculation of two-pipe system
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CHAPTER 8 TECHNICAL DATA, FORMULAS AND CHARTS
SI-units.Effect, P. Pressure, p.
W kcal/h Pa kPa bar mWG
1 0,85985 1 0,001 0,00001 0,0001
1,163 1 1.000 1 0,01 0,1
100.000 100 1 10
10.000 10 0,1 1
Flow, Q (). Temperature, t ().l/s m3/h Kelvin K Celsius oC
1 3,6 0 -273,150,278 1 273,15 0
373,15 100
Greek alphabet.
alfa beta gamma delta epsilon seta eta theta iota
kappa lamda my ny xi omikron pi ro sigma
tau ypsilon phi chi psi omega
Physical properties for water.
Temperature Pressure Density Isobaric heat
oC p kPa kg/m3 capacitivitycp J/ (kg x K)
0 - 999,84 421810 - 999,70 419220 - 998,205 418230 - 995,65 417840 - 992,2 4178
50 - 998,14 418160 - 983,21 418470 - 977,78 419080 - 971,80 419690 - 965,33 4205100 1,3 958,35 4216110 43,26 951,0 -120 98,54 943,1 4245130 170,11 934,8 -140 261,36 926,1 4287150 375,97 916,9 -
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CHAPTER 8 TECHNICAL DATA, FORMULAS AND CHARTS
8 STEPS - CONTROL OF HEATING SYSTEMS