Dear All, how to size hot water 3

• May 8, 2017

• #2

PEDARRIN2

Mechanical

Oct 1, 2003

1,287

US

Same way you size it for copper pipe.

Determine the heat loss per foot of pipe with(out) insulation and determine the flow rate that will enable you to provide enough flow to counteract this. Size the pipe for that flow rate.

 

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• May 8, 2017

• Thread starter
• #3

Mr.zoro

Mechanical

Mar 9, 2017

14

SA

you mean to use the same table of heat loss for copper pipe with any pipe material PPR or CPVC

 

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• May 8, 2017

1
• #4

PEDARRIN2

Mechanical

Oct 1, 2003

1,287

US

Maybe.

I never depend on tables without understanding what they represent.

As an exercise, you should use the thermal conductivity of the pipe material in question in the heat transfer equation to get real numbers. Then compare to the tabulated values.

If you are insulating the plastic pipe, the total heat loss will be comparable to that of insulated copper since the insulation provides enough resistance to heat flow that the difference in conductivity of the pipe material is insignificant.

If you are not insulating the pipe, then the difference in material will play out.

Since copper tubing and the plastic pipe material have essentially the same roughness (epsilon), there is not significant difference in the friction loss - but you do have to consider the difference in pipe inner diameter.

 

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• May 9, 2017

• Thread starter
• #5

Mr.zoro

Mechanical

Mar 9, 2017

14

SA

thank you for your reply PEDDARIN

 

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• May 9, 2017

1
• #6

mk3223

Mechanical

Feb 4, 2006

1,488

US

Refer to link below for the IECC code requirement for both copper and plastic pipes with insulation.

http://insulationinstitute.org/wp-content/uploads/2015/11/CI226.pdf

 

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• May 11, 2017

1
• #7

bimr

Civil/Environmental

Feb 25, 2003

9,380

US

Grundfos has a seminar on this topic:

https://go.bluevolt.com/Grundfos/Co...howScheduleForEventType?eventTypeName=Webinar

 

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• May 22, 2017

• #8

daaguirre

Mechanical

Jun 2, 2016

19

CA

Mr. Zoro

You can use 3Eplus to calculate the heat loss per linear ft for different pipe and insulation configurations. Its free.

 

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