program
Výrobní program O firmě Certifikáty Ceník Kontakty
1. Pre-insulated Pipeline Systems
Introduction – General Information
Applied Materials
Medium-Conducting Pipeline
Insulating Layers
Outer Protective Layers
Pipeline and Fittings
PIP 130 A, B, C
PIP 180 A, B, C
PIP 210, 240, 270
PIP 300 A, B, C
Elbows, Branches, Reducers, Compensators, Fixed Points
Accessory Parts - Entries, Pipeline Ends, Expansion Cushions
Mounting Instructions for Pipeline Connection, Coupling Design
Safety Regulations
Handling, Storage
Planning Activity Documents
Earth Works
Heat Dilatation PIP
Solution of Heat Dilatation
Compensating Bodies L, Z, U
Heat Tensioning of Pipeline
Axial Compensators
Steam Distribution System
Installation Length, Friction Forces, Pipe Cross-Sections
Monitoring System
2. Production Assortment of the Company IZO

Thermal Losses of Distribution Systems

The design thermal insulation according to ČSN 38 3350 as economic corresponds usually to realization time . However, it is desirable to consider this insulation from the point of view of price relations of transmitted energy.

Thermal losses of an independently laid pipe

Q =  Δ T
     [Wm-1]

Rc
where: Δ T = Tm - Tz,  i.e. temperature difference of the medium Tm (eventually mean temperature of the medium) and of the earth Tz, at full-year operation 10 °C, at operation for the period of heating season 5 °C.





At bedding into low depth it is the ratio:  burial depth of pipeline axis
 < 1,25

outer pipeline diameter

As the design temperature we use the mean annual at temperature in given area.

Rc - sum of all heat transmission resistances of the pre-insulated pipeline:

Rc = 
1

2π . λPUR
 . ln 
DPUR

dPUR
 + 
1

2π . λPE
 . ln 
DPE

dPE
 + 
1

2π.λz
 . ln 
4h

DPE
    [°KmW-1] 

where:  λPUR  =  coefficient of thermal conductivity (calculating) of the thermal insulation = 0,03 Wm-1K-1
λPE  =  coefficient of thermal conductivity of the HD-PE coat = 0,43 Wm-1K-1
λz  =  coefficient of thermal conductivity of earth = 0,8 - 2,0 Wm-1K-1
DPUR  =  outer diameter of the insulating layer [m]
dPUR  =  inner diameter of the insulating layer [m]
DPE  =  outer diameter of the HD-PE protection pipe [m]
dPE  =  inner diameter of the HD-PE protection pipe [m]
h  =  height of the covering layer from the pipeline axis [m]

For conventional bedding, i.e. the inlet and return pipe, it is to respect interferences and define secondary heat transmission resistance:


where b = distance between axes of two pipelines [m]

Overall loss of double-pipe distribution system

Qc = Q1 + Q2      [Wm-1]

Q1 = 
ΔT1Rc1 - ΔT2Rc1

R2c - R2m
    [Wm-1]    ;     Q2 = 
ΔT2 . Rc1 - ΔT1 . Rc1

R2c - R2m
    [Wm-1] 

In calculation of the total resistance there was ignored the resistance between the medium and the pipeline and the heat transmission resistance of the steel pipeline.

With respect to the same dimensions of the pre-insulated pipeline, inclusive of the same insulation thickness, it is valid:

Rc1 = Rc2

In calculation of the pre-insulated pipelines for temperatures 180 °C and 300 °C the following formula is valid:

Rc = 
1

2π . λR
 . ln 
DR

dR
 + 
1

2π . λPUR
 . ln 
DPUR

dPUR
 + 
1

2π.λPE
 . ln 
DPE

dPE
 + 
 + 
1

2π.λz
 . ln 
4h

DPE
    [KmW-1] 

where:  λR  -  coefficient of thermal conductivity of min. layer = 0,035 Wm-1K-1
DR  -  outer diameter of the first insulating layer
dR  -  inner diameter of the first insulating layer





Example of thermal losses calculation by reference of the chart with heat transfer coefficients "k"

Version:    inlet + return pipe    90/70 °C
earth temperature    10 °C

Q = k . (tpř + tzp - 2tz)          [Wm-1]

For given example: DN 100/200
                                         Q = 0,283 . (90 + 70 - 20) = 39,62 Wm-1

Pre-insulated Pipeline PIP 130 - Version A, B, C

DN [mm] D [mm] k [Wm-1K-1]
A     B     C A         B         C
20 90 / 110 / 125 0,150 / 0,129 / 0,119
25 90 / 110 / 125 0,182 / 0,153 / 0,138
32 110 / 125 / 140 0,187 / 0,166 / 0,152
40 110 / 125 / 140 0,217 / 0,188 / 0,170
50 125 / 140 / 160 0,243 / 0,212 / 0,184
65 140 / 160 / 180 0,286 / 0,238 / 0,207
80 160 / 180 / 200 0,296 / 0,249 / 0,219
100 200 / 225 / 250 0,283 / 0,241 / 0,213
100 200 / 225 / 250 0,310 / 0,260 / 0,228
125 225 / 250 / 280 0,332 / 0,279 / 0,240
125 225 / 250 / 280 0,363 / 0,301 / 0,255
150 250 / 280 / 315 0,379 / 0,310 / 0,260
150 250 / 280 / 315 0,432 / 0,342 / 0,282
175 280 / 315 / 355 0,463 / 0,359 / 0,293
200 315 / 350 / 400 0,467 / 0,362 / 0,295
250 400 / 450 / 500 0,448 / 0,353 / 0,295
300 450 / 500 / 560 0,519 / 0,404 / 0,326
350 500 / 560 / 630 0,505 / 0,388 / 0,313
400 560 / 630 / 710 0,536 / 0,403 / 0,322
450 630 / 710 / 800 0,538 / 0,402 / 0,321
500 710 / 800 / 900 0,520 / 0,392 / 0,320

Pre-insulated Pipeline PIP 180 - Version A, B, C

DN [mm] D [mm] k [Wm-1K-1]
A     B     C A         B         C
20 160 / 180 / 200 0,115 / 0,107 / 0,101
25 160 / 180 / 200 0,132 / 0,121 / 0,114
32 180 / 200 / 225 0,140 / 0,130 / 0,120
40 180 / 200/ 225 0,154 / 0,142 / 0,130
50 200 / 225 / 250 0,167 / 0,152 / 0,140
65 225 / 250 / 280 0,183 / 0,166 / 0,152
80 250 / 280 / 315 0,191 / 0,172 / 0,155
100 280 / 315 / 350 0,206 / 0,183 / 0,164
100 280 / 315 / 350 0,218 / 0,193 / 0,172
125 315 / 350 / 400 0,226 / 0,198 / 0,176
125 315 / 350 / 400 0,239 / 0,208 / 0,184
150 355 / 400 / 450 0,241 / 0,209 / 0,185
150 355 / 400 / 450 0,259 / 0,223 / 0,196
175 400 / 450 / 500 0,265 / 0,228 / 0,203
200 400 / 450 / 500 0,317 / 0,265 / 0,232
250 450 / 500 / 560 0,379 / 0,314 / 0,264
300 500 / 560 / 630 0,433 / 0,347 / 0,284

Pre-insulated Pipeline PIP 210, 240, 270

DN [mm] D [mm] k [Wm-1K-1]
210  240  270 210  240  270
20 180 / 200 / 225 0,109 / 0,104 / 0,099
25 180 / 200 / 225 0,123 / 0,117 / 0,110
32 200 / 225 / 250 0,132 / 0,124 / 0,117
40 200 / 225 / 250 0,144 / 0,134 / 0,126
50 225 / 250 / 280 0,154 / 0,144 / 0,134
65 250 / 280 / 315 0,169 / 0,156 / 0,143
80 280 / 315 / 315 0,174 / 0,159 / 0,161
100 315 / 355 / 355 0,185 / 0,168 / 0,170
100 315 / 355 / 355 0,195 / 0,176 / 0,178
125 355 / 400 / 400 0,201 / 0,180 / 0,182
125 355 / 400 / 400 0,211 / 0,189 / 0,191
150 400 / 450 / 450 0,212 / 0,190 / 0,191
150 400 / 450 / 450 0,226 / 0,200 / 0,202
175 450 / 500 / 500 0,231 / 0,207 / 0,209
200 450 / 500 / 500 0,269 / 0,237 / 0,239
250 500 / 560 / 560 0,317 / 0,270 / 0,273
300 560 / 630 / 630 0,349 / 0,289 / 0,293

Pre-insulated Pipeline PIP 300 - Version A, B, C

DN [mm] D [mm] k [Wm-1K-1]
A     B     C A         B         C
20 225 / 250 / 280 0,099 / 0,094 / 0,089
25 250 / 280 / 315 0,105 / 0,099 / 0,093
32 250 / 280 / 315 0,118 / 0,110 / 0,103
40 280 / 315 / 355 0,118 / 0,110 / 0,103
50 280 / 315 / 355 0,138 / 0,125 / 0,116
65 315 / 355 / 400 0,145 / 0,133 / 0,123
80 315 / 355 / 400 0,163 / 0,148 / 0,135
100 355 / 400 / 450 0,175 / 0,155 / 0,142
100 355 / 400 / 450 0,180 / 0,162 / 0,147
125 400 / 450 / 500 0,184 / 0,165 / 0,151
125 400 / 450 / 500 0,192 / 0,172 / 0,157
150 450 / 500 / 560 0,193 / 0,175 / 0,158
150 450 / 500 / 560 0,204 / 0,184 / 0,166
175 500 / 560 / 630 0,211 / 0,188 / 0,168
200 500 / 560 / 630 0,242 / 0,211 / 0,187
250 560 / 630 / 710 0,276 / 0,236 / 0,205
300 630 / 710 / 800 0,296 / 0,249 / 0,216

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