# What is the pressure to secure certain temperature?

How to calculate the pressure needed for a pump to ensure a specific temperature in a pipe?

For example, there is a pipe 100m long. A booster pump is needed to pump water with supply temperature 70 deg C. I need to ensure a temperature of 65 deg C at the end of the pipe. How can I calculate the pump pressure needed to ensure 65 deg C at the outflow?

• Is that 65 minimum or 65 maximum? Commented Feb 20, 2017 at 18:27
• 65degC is minimum. Commented Feb 21, 2017 at 9:24
• Considering the comments to the answer I think your question is poorly stated: you are interested in the flow rate through a pipe (and the required pressure drop to reach it) which gives you a certain outlet temperature given a certain external heat loss. Commented Mar 23, 2017 at 7:13
• I think minimum outlet temp 65 deg.C can be achieved in 2 ways: 1. For a given flowrate, pipe must be sufficiently insulated. So that as water flows, heat dissipated is limited. OR 2. For a given heat loss condition, flow must be quick enough so that water only have limited time inside the pipe. Commented Sep 15, 2020 at 4:46

## 1 Answer

Pressure adds only a to the temperature of water. Pump pressure allows water to be moved, it is not used to maintain the temperature of the fluid being pumped. To minimize thermal loss of fluid in a pipe, the pipe need to be sufficiently insulated.

• Unfortunately this is correct: compressive heating of water would require an excessively powerful pump and a precise nozzle at the pipe end (and then your temperature would drop as the water is ejected through the nozzle...). This endeavor would make a sense as a physics textbook homework, not as a practical usable device.
– SF.
Commented Feb 20, 2017 at 11:41
• He wants to lower the temperature as well, so he would want to maximize thermal loss depending on his outside conditions.
– JMac
Commented Feb 20, 2017 at 14:30
• Ok, but what about flow volume rate ? It definitely influences on the temperature. The higher volume flow rate the less temperature loss. So, how can I do calculation for this ? Commented Feb 21, 2017 at 9:27
• what about considering heat transfer along the length of the pipe? I think @OlegKhegay wishes to know what pressure and flow rate need be maintained to achieve the required temperature at the pipe exit!! Commented Feb 23, 2017 at 9:05
• Yes, you are right. So, any ideas ? Commented Feb 23, 2017 at 21:31