How do I convert kW to kWh for my project involving a heat exchanger?

  • Context: High School 
  • Thread starter Thread starter FQVBSina_Jesse
  • Start date Start date
  • Tags Tags
    Time
Click For Summary
SUMMARY

This discussion clarifies the conversion between kilowatts (kW) and kilowatt-hours (kWh) in the context of a heat exchanger project. A 60W device running for one hour consumes 60 Wh, not 60 kWh. The correct conversion is that 1 kW running for one hour equals 1 kWh, and 1 kWh is equivalent to 3412 BTU/hr. Additionally, it is emphasized that kWh must be converted by a factor of 3600 to relate it to kilojoules (kJ).

PREREQUISITES
  • Understanding of power and energy units (kW, kWh, BTU)
  • Basic knowledge of heat exchanger operation
  • Familiarity with unit conversions in thermodynamics
  • Concept of Joules as Watt-seconds
NEXT STEPS
  • Research the relationship between kW and BTU/hr for heating applications
  • Learn about the principles of heat exchangers and their efficiency
  • Explore energy conversion factors between different units (e.g., kWh to kJ)
  • Study the implications of using different energy units in engineering projects
USEFUL FOR

Engineers, energy analysts, and project managers involved in thermal systems, particularly those working with heat exchangers and energy conversions.

FQVBSina_Jesse
Messages
54
Reaction score
9
Say I have a 60W device.

I know running for one hour it uses 60 W x 3600 s = 216 kJ of energy.

Does that mean it uses 216 kWh of energy?

Or does kWh means 60 W x 1 hour = 60 kWh?

I am confused because the units in 60 kWh is not in their simplified terms.

More specifically, this pertains to a project that I am working on.
From experimental values, I found that with X kg/s of water flowing through the heat exchanger and some temperature increase, I can find the power of the heat exchanger in kW.
I would like to provide the values in BTU since that is just what people still use in the States.
I realized BTU is an energy unit, not power, and 1 kWh = 3412 BTU.
So I need to convert kW to kWh.
 
Science news on Phys.org
FQVBSina said:
Or does kWh means 60 W x 1 hour = 60 kWh?

you have a k in there that you shouldn't

60 W x 1 hour = 60 Wh

FQVBSina said:
So I need to convert kW to kWh.

so going from what I wrote above

a 1kW heater running for 1 hour = 1kWh
 
davenn said:
you have a k in there that you shouldn't

60 W x 1 hour = 60 Wh
so going from what I wrote above

a 1kW heater running for 1 hour = 1kWh
Alright, thanks! I thought kWh is basically kJ. I guess kWh needs to convert by a factor of 3600 before it becomes kJ then.
 
FQVBSina said:
More specifically, this pertains to a project that I am working on.
From experimental values, I found that with X kg/s of water flowing through the heat exchanger and some temperature increase, I can find the power of the heat exchanger in kW.

Yes that's possible/correct.

I would like to provide the values in BTU since that is just what people still use in the States.

I believe they actually use BTU/h (BTU per hour) but the "h" is sometimes omitted (bad practice).

So you just need to use..

1 kW = 3412 BTU/hr
 
FQVBSina said:
Alright, thanks! I thought kWh is basically kJ. I guess kWh needs to convert by a factor of 3600 before it becomes kJ then.
One thing worth remembering: a Joule is a Wattsecond.
So 3600 J = 3600 W s = 1 W h = 0.001 kW h .
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
4K
Replies
14
Views
2K
Replies
4
Views
1K