Pipe system life time cost

Energy will be increasingly precious

Environment focus will grow

The pipe system is expensive

Life time expectancy is over 30 Years

What is life time cost ?

Investment cost

– Pipe material

– Pipe installation

– Excavation and restoration

– Inspection

Operation cost

– Pumping

– Heat loss

Maintenance cost

– Repairs

– Management

The Calculation Example

The model system supplies 10 MW

Flow 90OC and return 50OC

The pipe system is:

2 x 1000 m. DN 250

2 x 1500 m. DN 80

100 consumer connections a´100 kW 2 x 2500 m. DN 32

100 consumer connections a´10kW 2 x 2000 m. 18 mm. Cu-flex

Investment cost Thump rules

Pipes 380 000 EUR

Insulation series 2 + 12%

Double Pipes + 25%

X-linked shrink joints +5%

Pipe installation 50% of pipes

Inspection 0- 50 000 EUR

Excavation 100% of pipes

Series 2 + 15%

Double – 20%

Asphalting 50% of pipes

Heat conductivity

PUR = SOLID +RADIATION +GAS

SOLID is not changing over time

RADIATION is not changing over time

GAS varies with the diffusion

SOLID +RADIATION app. 6 – 12 mW/mK depending upon the cell structure

The gas composition

The gas is Cyklopentane, CO2 and air

Cyklopentane, CP 40%

Carbon dioxide, CO2 55%

Air ( N2 + O2 ) 5%

Lambda gas

Cyklopentane: 0,012 W/mK

Carbon dioxide: 0,017 W/mK

Air: 0,027 W/mK

Lambda values new Logstor pipes

Conti pipes: 0.024 W/mK

Traditional pipes: 0,0275 W/mK

Flex pipes: 0,025 W/mK

Lambda ageingTraditional vs. Conti w. Barrier

22

23

24

25

26

27

28

29

30

31

32

33

New 5 Years 10 Years 15 Years 20 Years 25 Years 30 Years

22 Cu-flex

DN 32

DN80

DN250

LR-Conti

LR Cu-flex

mW/mK

German German failurefailure statisticstatistic

5

2000 25%

50%

4%

16%

5%

Weld seams

Joints

Casing+insulationDetectionsystemSundries

Swedish failure statisticsSwedish failure statistics

5

1998-200141%

45%

1%

12%

1%

Steel shells

Slide over

Weld joints

HDPE shrink

PEX shrink

Failure rates

With simple and cheap joints Joint failures may be > 0,5 failure/km./year

With PEX shrink joints or weld joints joint failures are < 0,05 failure/km./year

With low inspection rates Weld seam failures may be > 0,2 failure/km./year

With proper inspection Weld seam failures may be < 0,02 failure/km./year

Failure costs

The repair cost for a simple failure is estimated 3 000 EUR

The example: With cheap joints, repair cost is 20 000 EUR / year

With PEX- and weld joints, it is < 2 000 EUR / year

With low inspection, weld repair cost is 10 000 EUR / year

With proper inspection, it is 1 000 EUR / year

Do it cheap and easy and you have high repair costs

Do it right and you have low repair costs

Life time costs

The following picture compares:

“Series 1 cheap”:

DN 25, DN 32, DN 80, DN 250 all traditional without barrier, cheap joints and low inspection level.

“Series 1 barrier”:

18 Cu-flex, DN 32, DN 80, DN 250 Conti pipes with barrier, PEX joints and proper inspection

Series 2 barrier:

18 Cu-flex, DN 32, DN 80, DN 250 Conti pipes with barrier, PEX joints and proper inspection

Double pipes:

18 Cu-flex, DN 32, DN 80, all double and DN 250 Conti pipes with barrier, PEX joints and proper inspection

Const. Flow:

is Series 1 cheap with constant flow pumps

Life time costs

0

1000

2000

3000

4000

5000

6000

7000

Serie 1cheap

Serie 1Barrier

serie 2Barrier

Double constflow

Failures

Heatloss

Pumping

Inspection

Asphalt

Escavation

Installation

Pipes

kEUR Present values

Life time cost

Calculation settings:

Pumping energy 1% of total heat supply

Constant flow pumps 3% of total heat supply

Heat price 0,025 EUR/kWh

Power price 0,06 EUR/kWh

All amounts as present value over 20 years

Inflation 2%

Energy price rise 2%

Bank interest 6%

The lessons are:

Do not save on inspection

Do not accept “cheap” joints

Keep your heat loss down

Use flow controlled pumps