Insulation of high pressure vapour pipe in a Heat Pump.


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Old 10-15-11, 02:33 PM
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Insulation of high pressure vapour pipe in a Heat Pump.

I have a water to water heat pump which is used only for heating it is installed outside the insulation envelope of the house. Is it correct that the high pressure vapor pipe from the compressor to the condensing exchanger is not insulated, can I insulate it or will this cause some problem?
 
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Old 10-15-11, 09:17 PM
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The line may be too hot for the insulation. And I take it is a very short run anyway.
 
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Old 10-16-11, 09:31 AM
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Thank you. It seems to me that as heat pumps are traditionally used more for cooling than heating that the convention is not to insulate as the objective is to loose as much heat as possible at this point, with the heating application the conventional is carried without knowing why. The run is short but it is the warmest pipe in the whole system and it is not insulated so its a good few watts could be 50 to 100 I really don't know its dependent on deltaT.
 
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Old 10-16-11, 10:08 AM
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Heatpumps would be used more for heating! If not people would but only AC
 
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Old 10-16-11, 10:08 AM
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As said, you want to loose heat in this line so insulating would be counter productive.
You would be decreasing the condenser capacity when in air-conditioning mode.
 
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Old 10-16-11, 10:20 AM
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Why would I want to loose heat here, I want it to heat the water in the heating circuit at the condensing exchanger, not lost outside the insulation envelope at the heat pump.
 
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Old 10-23-11, 07:00 PM
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Originally Posted by JimUv View Post
Why would I want to loose heat here, I want it to heat the water in the heating circuit at the condensing exchanger, not lost outside the insulation envelope at the heat pump.
You are right. The vapor line is teh hot refrigerant line that is being used to heat the water. In a number of jurisdictions it is a code requirement to put 3/4" insulation on that line. The liquid line should also be insulated.

We have just installed an air source heat pump. Installation specs said to insulate both lines, but did not give thickness. We got 3/8" on both. I am going to add to this.

The insulation should be closed cell foam. This vendor has a write-up on heat pump refrig line insulation:

Armacell - Why do I need low-temperature insulation when installing a heat pump?
 
 

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