March 29, 2024, 03:29:45 AM
Forum Rules: Read This Before Posting


Topic: Help me. {Work}  (Read 3139 times)

0 Members and 1 Guest are viewing this topic.

Offline ian123

  • Regular Member
  • ***
  • Posts: 26
  • Mole Snacks: +0/-2
Help me. {Work}
« on: July 04, 2015, 11:23:19 AM »
A geothermal plant pumps water at 15 degrees celsius into the ground. The water travels through the pipes underground before returning to the surface at a temperature of 90 degrees celsius. If the efficiency of the plant is 10%, how much water must be pumped into the ground every second for the plant to generate 1MW of power?

I used Q=cm(deltaT)
and
n=W/(Q1)
 
Q1=energy input
W=work done of the engine
n=efficiency
c=energy gained per second
delta T= temperature difference
m=mass flow rate

(Q1)=1MW/0.1=10MW
m=(deltaQ)/(c*(deltaT))=10^4kW/((4.2kJ/kg*K)*(75K))=31.75kg/s
I want to know if I what I've done is right or wrong?
« Last Edit: July 04, 2015, 10:09:06 PM by Arkcon »

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27633
  • Mole Snacks: +1799/-410
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Help me.
« Reply #1 on: July 04, 2015, 11:46:54 AM »
You are on the right track, but lousy with math (which makes your answer wrong).
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline ian123

  • Regular Member
  • ***
  • Posts: 26
  • Mole Snacks: +0/-2
Re: Help me.
« Reply #2 on: July 04, 2015, 11:48:37 AM »
What have done wrong and what can I do to make it right?

Offline ian123

  • Regular Member
  • ***
  • Posts: 26
  • Mole Snacks: +0/-2
Re: Help me.
« Reply #3 on: July 04, 2015, 11:57:46 AM »
I think I have done it. Have I done it?

Offline ian123

  • Regular Member
  • ***
  • Posts: 26
  • Mole Snacks: +0/-2
Re: Help me.
« Reply #4 on: July 04, 2015, 11:58:12 AM »
Yes or no?

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27633
  • Mole Snacks: +1799/-410
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Help me.
« Reply #5 on: July 04, 2015, 05:50:25 PM »
Be patient, I don't spend my whole life on the forum.

Yes, it looks reasonably correct now.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline ian123

  • Regular Member
  • ***
  • Posts: 26
  • Mole Snacks: +0/-2
Re: Help me.
« Reply #6 on: July 04, 2015, 07:28:40 PM »
Thanks ;D

Sponsored Links