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Solair
09-12-2014, 07:58 PM
Evening guys.
Is the following statement true or false?

"A heat pump doesn't produce 3kw of heat from 1kw of energy. In fact it doesn't produce any heat at all. (well, aside from incidental heat produced by the system) What is does is take existing heat and simply move it from one place to another."

Thanks for reading.

chemi-cool
09-12-2014, 08:27 PM
I would not use that explanation but its true.

PaulZ
10-12-2014, 12:00 AM
Hi Solair
The First Law of Thermodynamics says that energy under normal conditions cannot be created or destroyed, simply transformed from one type of energy to another. So as Chemi-cool said it is true.
Regards
Paul

Solair
10-12-2014, 07:46 PM
Thanks.
That's depressing. :(

RANGER1
10-12-2014, 08:43 PM
I see it as transferring heat from one place to another, but heat of compression is on top of that.

There is also absorbed power in Kw & refrigeration Kw

So I think statement is FALSE

Solair
10-12-2014, 09:32 PM
Energy is power integrated over time.

So is saying "from 1kw of energy" not flawed?

I'd be interested in a better way of writing the statement.

Josip
10-12-2014, 11:06 PM
Hi, Solair :)


Evening guys.
Is the following statement true or false?

"A heat pump doesn't produce 3kw of heat from 1kw of energy. In fact it doesn't produce any heat at all. (well, aside from incidental heat produced by the system) What is does is take existing heat and simply move it from one place to another."

Thanks for reading.



We need to use 1kW of external work to pump 3 kW of energy from cold area to warm area (opposite flow is a natural way and no need to input any work) ... and here we are speaking only about COP ... how much unit of Work we have to use to move that much units of energy QH ....

COP= QH/W

statement is false ... i.e. not correct

Best regards, Josip :)

Rob White
10-12-2014, 11:11 PM
Evening guys.
Is the following statement true or false?

"A heat pump doesn't produce 3kw of heat from 1kw of energy. In fact it doesn't produce any heat at all. (well, aside from incidental heat produced by the system) What is does is take existing heat and simply move it from one place to another."

Thanks for reading.




I'm too keen on the way it is wrote, but in principle it is true.


Thanks.
That's depressing. :(


???????? Why


Energy is power integrated over time.

So is saying "from 1kw of energy" not flawed?

I'd be interested in a better way of writing the statement.




I'm not sure what you are trying to say?

A heat pumps take available energy and transfers it to somewhere else.
That comes at a cost and the cost is the conversion of electrical energy
into heat energy.

However you want to explain it, it is only a transfer of heat.

Rob

.

chemi-cool
11-12-2014, 06:13 PM
Hi, Solair :)



We need to use 1kW of external work to pump 3 kW of energy from cold area to warm area (opposite flow is a natural way and no need to input any work) ... and here we are speaking only about COP ... how much unit of Work we have to use to move that much units of energy QH ....

COP= QH/W

statement is false ... i.e. not correct

Best regards, Josip :)


Josip my dear friend, lets discuss the issue,
That first sentence ( A heat pump doesn't produce 3kw of heat from 1kw of energy) to my opinion, is a trap, and you fell for it.
It is not true that heat pump does not produce any heat, a motor is running, there is friction > heat is generated.

The heat pump does moves the existing heat from one substance to another using refrigerant, part of that heat is coming from the refrigerant pump motor.

Still, it only moves heat from one place to another.

limor sends her regards.

Solair
11-12-2014, 07:52 PM
Who is Limor?

chemi-cool
11-12-2014, 08:31 PM
Who is Limor?

that was for josip, my other half.

Rob White
11-12-2014, 08:35 PM
.

Your flitting around way too fast for me :confused:

Where does Limor come into this?

You need to ask a complete sentence and if you ask a
question you need to ask it in a way we or specifically
I can understand.

Rob

.

Josip
11-12-2014, 11:24 PM
Hi, chemi :)


Josip my dear friend, lets discuss the issue,
That first sentence ( A heat pump doesn't produce 3kw of heat from 1kw of energy) to my opinion, is a trap, and you fell for it.
It is not true that heat pump does not produce any heat, a motor is running, there is friction > heat is generated.

The heat pump does moves the existing heat from one substance to another using refrigerant, part of that heat is coming from the refrigerant pump motor.

Still, it only moves heat from one place to another.

limor sends her regards.


Not sure, whatever, maybe I fell, but what if we assume ... this like a theoretical discussion and I assume this process is ideal - Carnot ...

as you know English is not my mother tongue and for me is easy to be trapped by language ... and fell on examination ;)


Best regards to Limor and to you, :)