×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

heat energy required to heat liquid flowing through pipe

heat energy required to heat liquid flowing through pipe

heat energy required to heat liquid flowing through pipe

(OP)
I have to heat up some oil flowing through a 1" pipe. I need to know the equation (mind is hazy now).
I want to use an electrical resistance heater to heat the fluid.  Fluid is oil, about 140W gear oil.
I just want to get into the ballpark to size the heater.

Need to raise the temp from ~0*C to ~40*C. Flow rate is about 3 gallons per day.
It's for the cylinder lube oil on a natural gas compressor.  It's a high pressure application, so it requires very viscous lube oil for the cylinders, which means we have to keep it warm, because at freezing ambient temps it will not flow very well. So I'm thinking about some type of electrical resistance heater over the piping.

This is a repost from
http://www.eng-tips.com/viewthread.cfm?qid=227618&page=1

Hoping that this forum is more appropriate.
Thanks

RE: heat energy required to heat liquid flowing through pipe

Q = w.Cp.ΔT

Good luck,
Latexman

RE: heat energy required to heat liquid flowing through pipe

To expand on Latexman's correct formula, and with apologies if I'm belaboring the point:

Q is the energy required to change the temperature
w is the flow rate
cp is the thermal capacitance of the oil
and ΔT is the change in temperature

Obviously, you need to make sure all your units are compatible.

The hard part may be coming up with the cp value for your lube oil.  I don't have any good values for that weight oil. Your best bet may be going back to the oil distributor.  

Patricia Lougheed

Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

RE: heat energy required to heat liquid flowing through pipe

(OP)
Thanks a bunch guys!
That's about what I had come up with, but was having a tough time finding the Cp for my oil... I'll dig some more.

W is the flow rate, in mass or volume flow rate?
Thanks

RE: heat energy required to heat liquid flowing through pipe

it should be in kg/sec for metric units.  English units, it's lbm/sec.

Patricia Lougheed

Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

RE: heat energy required to heat liquid flowing through pipe

(OP)
Great!  Thanks guys.

Yea i'm not too worried about loses, I just to be in the ballpark, to see how much electricity I need to budget for.

Thanks again

RE: heat energy required to heat liquid flowing through pipe


A rough specific heat capacity of 1800 J/(kg.K) would be, as you say, in the ballpark.

RE: heat energy required to heat liquid flowing through pipe

The energy required to heat up the oil - as calculated by the above formula - will be trivial in comparison to the losses to ambient with a 40C delta-T.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources