Assumed violation of physics - Heat vs. Work

[Tom Booth]

Then it definitely isn't a heat pump any more, it is really just a paperweight.

Well, now that we have the doors off, let's try plugging it back in.

Is it a heat pump again instead of a paperweight ?

I think so. But it is just pumping heat from the condenser coil to the expansion coil. Taking heat out of point A in the reservoir to point B. Moving heat from one location to another within a single "reservoir" No ?

Again, the hot and cold reservoirs are part of the definition of a heat pump.

It depends on what definition you read and how good the dictionary is.

What is the point of these questions?

The point is that a heat pump and an engine working together, regardless of if that is considered possible or not, does not necessitate that both work between the same two "reservoirs".

I also kind of object to the use of the colloquial term "reservoir" as used in relation to HEAT as the term "Heat reservoir" was coined when heat was still considered an actual fluid. A reservoir being by definition, a place or container for storing a fluid. Heat is not a fluid and continuing to think of heat in terms of a fluid is false and numbs the brain.

By way of explanation, I just came here out of curiosity to see why the topic starter (Low-Q) wanted to use the diagram I posted in another forum.

Naturally I find the topic mater interesting and couldn't help getting drawn in. My apologies.

A heat pump, stripped of all its non-essentials does not IMO depend for its operation in any way on the existence of two pre-existing "reservoirs".

Take the actual working unit out of whatever its in and set it on a table in a room where everything is the same temperature and there are no TWO separate Hot and Cold areas of any kind with any temperature difference that can be measured with a thermometer.

Plug it in and a temperature difference is CREATED.

The condenser coil gets hot and the expansion coil gets cold. If you want to call these coils "reservoirs" I guess that's fine but I think it is very misleading. At any rate, the heat pump does not depend on this temperature difference for its operation. It creates the temperature difference where there wasn't one before.

To insist that it is more or less efficient depending on the temperature of the two "reservoirs" is, I think, also misleading. It works to create a temperature difference sitting on a table. The idea of efficiency to heat your home or cool your food has to do with the specific application. Sitting on a table, not applied to anything, not being used to heat or cool any two different spaces it works to create a temperature difference where there was none before just the same.

 

[Drakkith]

To insist that it is more or less efficient depending on the temperature of the two "reservoirs" is, I think, also misleading. It works to create a temperature difference sitting on a table. The idea of efficiency to heat your home or cool your food has to do with the specific application. Sitting on a table, not applied to anything, not being used to heat or cool any two different spaces it works to create a temperature difference where there was none before just the same.

I think you just want to argue definitions instead of understanding the concept. The heat pump, after you throw it on the table, is now in ONE reservoir. You cannot create a temperature difference with only one reservoir. You could argue that it is creating a temperature difference between the input/output sides, and that would be true, but the room overall is your reservoir and you would not have any net change in the temperature in the room. (Except for the addition of heat by the workings of the pump.)

 

[Dale]

It depends on what definition you read and how good the dictionary is.
...
A heat pump, stripped of all its non-essentials does not IMO depend for its operation in any way on the existence of two pre-existing "reservoirs".

If you can find a mainstream scientific source which defines a heat pump differently then please provide the reference. Otherwise we will stick with the standard definition:

http://en.wikipedia.org/wiki/Heat_pump
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatpump.html
http://www.ecourses.ou.edu/cgi-bin/ebook.cgi?doc=&topic=th&chap_sec=05.5&page=theory
http://www.ohio.edu/people/piccard/phys202/carnot/carnot.html

The point is that a heat pump and an engine working together, regardless of if that is considered possible or not, does not necessitate that both work between the same two "reservoirs".

I agree. That is simply how Low-Q drew the arrangement. I even proposed and analyzed an alternate arrangement where they only shared one reservoir. But Low-Q's arrangement clearly has both the heat pump and the heat engine connected to the same two heat reservoirs. I would be glad to discuss and analyze alternate arrangements.

However, in order to be a heat engine and in order to be a heat pump each must be connected to two reservoirs. They need not be the same reservoirs, but each needs two, by definition.

To insist that it is more or less efficient depending on the temperature of the two "reservoirs" is, I think, also misleading.

It isn't misleading in the least, it is completely factual. Engineers have been analyzing, designing, and building heat pumps based on this fundamental fact for decades. All heat pumps ever constructed share this feature: the greater the temperature difference between the hot and cold reservoirs the less heat is transferred for the same amount of work input by the formula above*. Your complaint to the contrary is unfounded and goes against both fact and theory.

*Actually, this is for an ideal heat pump. Real heat pumps are even LESS efficient.

 

[Tom Booth]

I think you just want to argue definitions instead of understanding the concept.

Not really. But if we are going to talk sensibly then there needs to be some clarity regarding terminology. Sometimes the terminology or how exactly it is defined limits conceptualization to certain predetermined pathways.

The diagram is just a kind of energy flow chart. I just dashed it off. I'm not sure that Low-Q in his enthusiasm actually understood it fully. I never really explained it in the other forum where it was posted.

The actual working principle was outlined in an article by Tesla. I'm not so sure myself that the concept could actually work but so far I've seen no mention here of the working principle it is supposed to represent.

The heat pump, after you throw it on the table, is now in ONE reservoir.

So we are in agreement on that point.

You cannot create a temperature difference with only one reservoir.

You could argue that it is creating a temperature difference between the input/output sides,

Of course I would. Wouldn't you ? (And it is).

and that would be true

Naturally.

but the room overall is your reservoir and you would not have any net change in the temperature in the room.

True. But so what ?

I can still take the condenser coil and the expansion coil and twist one or the other or both around one or both ends of the heat engine and the heat engine will still run. All within the same "reservoir" as we have already agreed.

At any rate, Tesla's idea as represented in the diagram could not really be understood, I don't think, if it cannot be grasped that the only REAL permanent "reservoir" of heat represented in that diagram is Ambient Heat. Both the heat pump and the engine are operating within that one environment.

There is a "Heat Sink" of sorts which might be considered a "reservoir". About as much so as the evaporator coil of a heat pump sitting on a table. But we have dispensed with that notion.

The heat pump in the diagram is maintaining an artificial heat sink within the ambient environment. That is not really a "reservoir". Not in the sense that term is generally used. Naturally, this artificial sink would have to be protected. Insulated. Like an ice box. The only heat entering the ice box would be the waste heat from the engine.

I'm not at all sure that Low-Q fully understood all that. Maybe it isn't essential to his argument. I don't know. I thought some clarification might be in order anyway.

To understand what Tesla was driving at, it is also important to understand that heat is not really a fluid that flows from hot to cold like water. That was central to his argument. But that is essentially what is meant when using the term "reservoirs". Heat is energy which can be transmuted into other forms of energy.

It is the role of a heat engine to transmute heat into some other useful form of energy.

Not all the heat running the engine flows from the heat source into the heat sink. If the heat engine is efficient then it won't be dumping much waste heat into the "ice box".

 

[Drakkith]

Tom you seem to have written a lot without saying anything at all. What is the point of your posts? That heat isn't a fluid? That's pretty obvious. Was there some other point you wanted to make? Please elaborate if so. It appears as if you just want to argue what a reservoir is when we already have a perfectly good definition and description of one.

 

[Tom Booth]

If you can find a mainstream scientific source which defines a heat pump differently then please provide the reference. Otherwise we will stick with the standard definition:

http://en.wikipedia.org/wiki/Heat_pump
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatpump.html
http://www.ecourses.ou.edu/cgi-bin/ebook.cgi?doc=&topic=th&chap_sec=05.5&page=theory
http://www.ohio.edu/people/piccard/phys202/carnot/carnot.html

One of your sources states clearly: "A heat pump is a device which applies external work to extract an amount of heat QC from a cold reservoir and delivers heat QH to a hot reservoir"

Fair enough. But I would argue that that is a definition of its usual function. Not what it actually does or can do.

The heat pump can still operate even if used outside its intended function.

Rather than using a heat pump to extract heat from a cold environment and deliver it to a hot environment, as defined above, you could just as well use it to extract heat from a hot environment and deliver it to a cold one. That doesn't meet the definition of heat pump but it would still work. You can also just run it in one environment which is stable in temperature throughout and make it unstable. Create a temperature difference where there was none.

Perhaps if used in an unusual way it would be better to call it something else. A "generic vapor compressor unit" perhaps. or come up with some other applicable term. A rose by any other name is still a rose.

In my opinion the best definition is simply what is implied by its name. Heat Pump.

It pumps heat from point A to point B Period.

...But Low-Q's arrangement clearly has both the heat pump and the heat engine connected to the same two heat reservoirs.

That is a result of his haste or enthusiasm to use the diagram before I explained it in detail in the other forum. As he did not clarify the nature of the apparent cold reservoir, I have made an effort to do so.

However, in order to be a heat engine and in order to be a heat pump each must be connected to two reservoirs. They need not be the same reservoirs, but each needs two, by definition.

By definition a computer monitor is not a television set. But the definition is FUNCTIONAL.

Otherwise at heart, they are both simply cathode ray tubes.

I do not agree that a heat pump "MUST be connected to two reservoirs". To meet the usual definition Yes. To actually function as a machine No.

It isn't misleading in the least, it is completely factual. Engineers have been analyzing, designing, and building heat pumps based on this fundamental fact for decades. All heat pumps ever constructed share this feature: the greater the temperature difference between the hot and cold reservoirs the less heat is transferred for the same amount of work input by the formula above*. Your complaint to the contrary is unfounded and goes against both fact and theory.

My argument is not about the factuality of the above statement but with the implication that there MUST BE a HOT and a COLD "reservoir" for a bare bones vapor compressor unit to operate and create a temperature difference.

If you think this is really a necessity or the machine can't work then I would suggest that you strip one down and plug it in and see what happens.

A central air unit (heat pump) sits where ?

Generally it sits outside behind the house in the ambient environment.

You can only get it to deliver heat to the house by using fans and running ductwork but without the ductwork, just sitting outside it will still operate and create a temperature differential.

It doesn't deliver the heat to the "reservoir" inside the house as intended so I guess you can't really call it a heat pump any more and it is no longer "efficient" at heating the house without the ductwork but it is creating heat and cold under the hood just as well as ever. Ductwork or no ductwork. Its actual capability to produce hot and cold from the warm ambient environment has not diminished in the least by removing the ductwork.

 

[Tom Booth]

Tom you seem to have written a lot without saying anything at all. What is the point of your posts? That heat isn't a fluid? That's pretty obvious. Was there some other point you wanted to make? Please elaborate if so. It appears as if you just want to argue what a reservoir is when we already have a perfectly good definition and description of one.

Not what a reservoir IS.

You wrote a few minutes ago:

You cannot create a temperature difference with only one reservoir.

You could argue that it is creating a temperature difference between the input/output sides,

and that would be true

A temperature difference is a temperature difference isn't it ?

The input/output sides are both within the one reservoir. Right ?

It seems to me that you certainly can indeed "create a temperature difference with only one reservoir" I don't know if it is the terminology that needs clarification or what but it appears you contradict yourself. Is it possible or isn't it ? Does a temperature difference exist or not ?

If you can't create a temperature difference with only one reservoir but there is a temperature difference nevertheless then where is the other reservoir ?

 

[Studiot]

A temperature difference is a temperature difference isn't it ?

The input/output sides are both within the one reservoir. Right ?

It seems to me that you certainly can indeed "create a temperature difference with only one reservoir" I don't know if it is the terminology that needs clarification or what but it appears you contradict yourself. Is it possible or isn't it ? Does a temperature difference exist or not ?

If you can't create a temperature difference with only one reservoir but there is a temperature difference nevertheless then where is the other reservoir ?

I can see two different scenarios here.

1) You genuinely want to understand the thermodynamics of heat flow.

2) You just want to argue the toss and and trying to revise standard definitions to suit your case.

I am happy to help in (1) but not (2).

 

[sophiecentaur]

If a heat pump is put on a table and switched on, it will just develop one hot plat and one cold plate. It still pumps heat - just aimlessly, not achieving anything.

 

[Studiot]

Good morning SophieCentaur

If a heat pump is put on a table and switched on, it will just develop one hot plat and one cold plate.

That's true because the heat pump has created a hot reservoir and a cold reservoir.
It maintains these according to the Second Law by the input of work.

This part of thermodynamics is actually very easy to understand for those who want to ( as you clearly do).

 

[Low-Q]

After reading the last posts I have a strong feeling that the inner workings of a heat pump is often misunderstood.
At least I see myself looking at a heat pump as something that can make a temperature difference between expansion- and condensing parts that is greater than the input work. Naturally I think so when a heat pump (If used as a heat source for the house), can deliver more heat pr. input Watt than a resistive electric heater does.

So if I understand the replies from DaleSpam, I could likely used a regular resistive heater to power that heat engine, and have the same consume/output as if I was using the condenser or expansion part of a heat pump, or even both, to run the heat engine.

The heat engine in a closed loop will take heat from the hot condenser and deliver it to the cold expander. This will prevent the condenser to be too hot to be able to condense the working fluid, and prevent the expander to be too cold to expand the working fluid.
Initially, the pump must do work in order to maintain the pressure difference between high pressure hot condenser and low pressure cold expander. That input work increase as the temperatur difference gets higher - COP drops. If a heat engine is trying to equalize those two temperatures, the pump will have less temperature difference which will reduce input work - COP rise, but also the heat engine will have less temperature difference to work on and then decrease its efficiency. This is how I understand a closed insolated loop.

However, the confusion comes when I look at the power requirements for a resistive heater to heat up a given insolated space (house) versus the power requirements for a heat pump to deliver the same heat into the same space. The heat pump heats up the house on expence of the outside temperature, while the resistive heater does not.
Since the air outdoor has a pretty large volume, it will practically not change its temperature. That reservoire is too large for the heat pump to cool it considerably down.
The same reservoire is also too large for the heat engine heat it up.

This gives me headache

 

[Tom Booth]

A temperature difference is a temperature difference isn't it ?

The input/output sides are both within the one reservoir. Right ?

It seems to me that you certainly can indeed "create a temperature difference with only one reservoir" I don't know if it is the terminology that needs clarification or what but it appears you contradict yourself. Is it possible or isn't it ? Does a temperature difference exist or not ?

If you can't create a temperature difference with only one reservoir but there is a temperature difference nevertheless then where is the other reservoir ?

I can see two different scenarios here.

1) You genuinely want to understand the thermodynamics of heat flow.

2) You just want to argue the toss and and trying to revise standard definitions to suit your case.

I am happy to help in (1) but not (2).

As far as what you quoted of my post, I'm simply trying to get Drakkith to clarify his position when he wrote:

The heat pump, after you throw it on the table, is now in ONE reservoir.

You cannot create a temperature difference with only one reservoir.

You could argue that it is creating a temperature difference between the input/output sides,

and that would be true

To me the statement is contradicting itself. If he agrees that the heat pump is "now in one reservoir" just sitting on a table creating a temperature difference "between the input/output sides" than how can he say in the same breath "You cannot create a temperature difference with only one reservoir." ?

Something doesn't click. I would simply like to reach a mutual understanding or at lest some clarity about whatever it is he's trying to say. Is that too much to ask ?

 

[Drakkith]

A temperature difference is a temperature difference isn't it ?

The input/output sides are both within the one reservoir. Right ?

It seems to me that you certainly can indeed "create a temperature difference with only one reservoir" I don't know if it is the terminology that needs clarification or what but it appears you contradict yourself. Is it possible or isn't it ? Does a temperature difference exist or not ?

If you can't create a temperature difference with only one reservoir but there is a temperature difference nevertheless then where is the other reservoir ?

Oh. You are going to be difficult in this manner. Ok then. Let me be clear. You cannot create a temperature difference between two reservoirs if you don't have 2 reservoirs.

 

[sophiecentaur]

Where is this thread supposed to be going? The definitions are actually quite clear and there is plenty if evidence that there's no paradox or law-breaking. Some if the contributors just need to re-visit the thermodynamics in a rigorous way. They can then stop worrying and imagining they have found a loophole in Science.

 

[Crazymechanic]

Well you can create a temperature difference in the same reservoir or room in two objects but to do that you have to supply constant power to them for them to either stay hot or cold.Basically that is useless work as the temperature will try to reach equilibrium all the time.
That's like building a sand castle in heavy rain and storm you can do that but the rain will constantly wash away your castle and you will have to constantly build it up .

But I think the situation when two objects can have different temperatures in the same room is just because of air that air cannot make the temperatures equal out as fast because of it's properties while if you would have the same reservoir or room only this time not filled with air but water it would be a different situation the heat difference between something hot and cold would be almoust none.

@Low-Q yes your right that a electrical heater will consume more power to create the same amount of heat than a heat pump as the heat pump is not creating the heat just transporting it from one place to another, just like a cargo train isn't creating it's cargo just transporting it.
And if you have a heat pump heated house there is a temperature difference but then you break your window at come home after one day and there is no more temperature difference as the air outside and inside has reached equilibrium , the efficiency has decreased dramatically as it now is like a hydro dam with no dam at all , all the water is in the same level in our case temperature.

But basically I think the discussion between do we need two reservoirs or not is useless as in all cases there are two or more reservoirs of different temperatures like the one in your house and the one outside and then the one outside and the one in your basement or your fridge.

 

[Tom Booth]

If a heat pump is put on a table and switched on, it will just develop one hot plate and one cold plate. It still pumps heat - just aimlessly, not achieving anything.

Thank you.

But it is achieving something if you have an application for "one hot plate and one cold plate".

 

[Crazymechanic]

Well it has an application , but a pretty useless and inefficient one.
That's why they came up with the idea of putting a door to the fridge. :D Also I believe the same reason is used for windows just instead having empty holes for light to come in.

But actually I believe there is a situation where Tom's case applies , when they use the water cooled or other chemical cooled CPU coolers.
Because basically the inner space of the pc case with all the chipset and main cpu that is being cooled is not isolated from the outside where the radiator or heat exchanger is located so basically it's a little bit similar to pumping out water from a hole and displacing it right next to that hole and then very soon afterwards it goes through the soil and gets back into the hole.
Pretty inefficient as it's like having a fan in a vacuum , you can still spin it but without much use.
That's why I believe the huge server rooms are isolated from the outside and use heat pumps or we could say air conditioners to move the excess heat generated by the server equipment to the outside of the building as just having a small water cooled cpu head that displaces the heat right next to the server board wouldn't go through as the temperature of the server room would rise constantly until reach equilibrium or almoust close with the temperature of the cpu itself and then the local heat pump would have no use anymore. Just like in the scenario with the heat pump in one reservoir on table that you mentioned.

 

[Tom Booth]

That's true because the heat pump has created a hot reservoir and a cold reservoir.

So are we going with the idea that the condenser coil and the expansion coil of a stripped down vapor-compression unit running on the kitchen table constitute hot and cold reservoirs ?

The surrounding reservoir of ambient heat in the kitchen itself we can just ignore.

 

[Low-Q]

Where is this thread supposed to be going? The definitions are actually quite clear and there is plenty if evidence that there's no paradox or law-breaking. Some if the contributors just need to re-visit the thermodynamics in a rigorous way. They can then stop worrying and imagining they have found a loophole in Science.

Good point. However I am not searching for loopholes in science, just searching for an energysource in the air which a heat pump can harvest in order to power a heat engine. As many links, explanations from you guys has shown, it will not be possible.

@ Crazymechanic:
To use the cargo train as an example, that train is supplying the heat engine. I understand now that the heat engine is also a train which moves the same cargo back to its origin. The net movement of the cargo is zero - so no work has been done. The pump/engine system will therfor not work with only two reservoires.
To make this work we need a third reservoir. The ground for example. Its temperature will not change as much as the air temperature outside. At very hot or very cold days, the heat engine can be ran by those two reservoires. It powers the heat pump which removes heat from the house at warm days, and supply heat to the house at cold days. Lucky for us, the heat engine will increase its efficiency as the temperature difference is increasing.

Vidar

 

[Crazymechanic]

@Tom , no I don't think we can call those reservoirs as the classical understanding of a reservoir is something that is a closed room or space and it has to have some isolation from the surrounding.
When a heat pump is left in an open space with no isolation between the two sides it's not a heat pump any more by definition , just like if you have a jail and then you have a city the isolation of these two are the walls and guards of the jail if you take those away then there are no two spaces anymore all is one, the people just merge with all the consequences from that.@Low-Q , well I believe that what you wanted to make sounds similar to a hydro dam the water goes through the turbine gives it's potential to the turbine and then when it passes out of the dam at the lower side you somehow take it up to the high side of the dam again so that it could do the job one more time and repeat this in a loop but the problem is if you have to bring the water up you have to use energy and in the end the energy extracted from the falling water compared to the energy used to pump the fallen water back up would pretty much equal out. That's why a heat pump or a hydro dam can only create excess energy if the temperature/water difference is supplied by an external force like sun and water evaporation or sun and temperature difference between the two sides of the heat pump and then the pumps has only to move that heat but only in one direction.

 

[Low-Q]

@Low-Q , well I believe that what you wanted to make sounds similar to a hydro dam the water goes through the turbine gives it's potential to the turbine and then when it passes out of the dam at the lower side you somehow take it up to the high side of the dam again so that it could do the job one more time and repeat this in a loop but the problem is if you have to bring the water up you have to use energy and in the end the energy extracted from the falling water compared to the energy used to pump the fallen water back up would pretty much equal out. That's why a heat pump or a hydro dam can only create excess energy if the temperature/water difference is supplied by an external force like sun and water evaporation or sun and temperature difference between the two sides of the heat pump and then the pumps has only to move that heat but only in one direction.

Sounds reasonable. You pretty much nailed it

 

[Tom Booth]

Oh. You are going to be difficult in this manner. Ok then. Let me be clear. You cannot create a temperature difference between two reservoirs if you don't have 2 reservoirs.

OK, that seems clearer.

Comparing that to this:

The heat pump, after you throw it on the table, is now in ONE reservoir.

By "ONE reservoir" I assume you mean the ambient heat in the room the table is in. Yes?

You cannot create a temperature difference with only one reservoir.

By that then you actually mean as modified: "You cannot create a temperature difference between two reservoirs if you don't have 2 reservoirs." Yes ?

The source of my confusion was that I was interpreting your statement to mean: "You cannot use a heat pump to create a temperature difference from just the one reservoir it is in"

After all, it followed directly after your statement "the heat pump... is now in one reservoir"

I hope you can understand the reason for the misinterpretation.

You could argue that it is creating a temperature difference between the input/output sides,

and that would be true

I assume the last statement can stand. I'm content with considering the room the engine is in "one reservoir" and refer to the input and output sides as just that. I assume by "input and output sides" you mean the condenser coils and expansion coils of the heat pump. You do not however consider these to be hot and cold reservoirs. Am I correct ?

Studiot, however, just posted in regard to the same scinario:

If a heat pump is put on a table and switched on, it will just develop one hot plate and one cold plate.

That's true because the heat pump has created a hot reservoir and a cold reservoir.

 

[Tom Booth]

Where is this thread supposed to be going?

I believe Low-Q would like to use the temperature difference created by a heat pump to run a Stirling Engine, or some form of heat engine directly from the temperature difference and have the engine in turn run the heat pump with excess energy left over to spare to be used for some useful purpose like generating electricity.

That was my impression at the start.

 

[Studiot]

Good point. However I am not searching for loopholes in science, just searching for an energysource in the air which a heat pump can harvest in order to power a heat engine. As many links, explanations from you guys has shown, it will not be possible.

Of course it is possible.

But it is just that you can't have a closed system driving itself.
But you could power a heat engine of sufficiently lower power.

The originators of thermodynamics called this a 'self acting machine'

A popular goal was once the idea of extracting heat from the very large heat content of the ocean and converting it to mechanical work to drive the ship. Of course this was proved to be less efficient.

"It is impossible for a self acting machine, unaided by any external agancy, to convey heat from a cold body to a hot one"

There is a clear misconception as to the functioning of refrigeration plant in this thread, which in my opinion has lead to the difficulties with the Tom/Low-Q diagram.

No practical heat pump works by reversing the ideal machine cycle.
There is indeed an 'intermediate' temperature. I will come to that.
I think this is where the misunderstanding has arisen.

Here is a calculation for a perfect refrigerator formed from a perfect heat engine driving a perfect heat pump.

A perfect heat engine takes in heat, Q, at T and rejects heat at T₁

Hence
W = \frac{Q}{T}\left( {T - {T_1}} \right)

The perfect heat pump extracts Q₂ from the cold body at low temperature T₂. It also delivers heat to temperature T₁.

Since it is perfect and therefore reversible

W = \frac{{{Q_2}}}{{{T_2}}}\left( {{T_1} - {T_2}} \right)

Where W is the heat equivalent of work given by the heat engine and also the the work used in driving the heat pump.

Hence

\begin{array}{l}<br /> \frac{Q}{T}\left( {T - {T_2}} \right) = \frac{{{Q_2}}}{{{T_2}}}\left( {{T_1} - {T_2}} \right) \\ <br /> \frac{{{Q_2}}}{Q} = \frac{{{T_2}}}{T}\frac{{\left( {T - {T_2}} \right)}}{{\left( {{T_1} - {T_2}} \right)}} \\ <br /> \end{array}

Where \frac{{{Q_2}}}{Q} is the ratio of the heat extracted from the colder body to the heat supplied to the machine reservoir.


Note that the heats (Q₂) used in the calculation of the heat pump and the heat engine use heats at different reservoirs, which differ by the work performed.
Using the wrong Q is a common error by beginners.

 

[Tom Booth]

Good point. However I am not searching for loopholes in science, just searching for an energysource in the air which a heat pump can harvest in order to power a heat engine. As many links, explanations from you guys has shown, it will not be possible.

I'm disappointed. You give up far to easily.

 

[Dale]

The heat pump can still operate even if used outside its intended function.

Then it is not operating as a heat pump.

Tom, since you have not provided a reference to an alternative definition, I consider the discussion about the definition of a heat pump closed until you can do so.

This forum is not for personal speculation or personal theories. We only deal with mainstream science. In some cases there are multiple mainstream scientific definitions for the same term, in which case it is worth clarifying which definition is being used, but here there appears to be only one definition. Semantic arguments are boring, so I won't continue with this one.

That is a result of his haste or enthusiasm to use the diagram before I explained it in detail in the other forum. As he did not clarify the nature of the apparent cold reservoir, I have made an effort to do so.

I missed the clarification amidst all of the definition nonsense. Is the cold reservoir not shared?

 

[Tom Booth]

@Tom , no I don't think we can call those reservoirs...

I don't either.

 

[Dale]

The heat pump in the diagram is maintaining an artificial heat sink within the ambient environment. That is not really a "reservoir". Not in the sense that term is generally used. Naturally, this artificial sink would have to be protected. Insulated. Like an ice box. The only heat entering the ice box would be the waste heat from the engine.

That is exactly what I assumed when I analyzed it above. As I showed above, even for an ideal heat engine and heat pump you would have to use all of the work from the heat engine to run the heat pump. For a real heat engine you will get even less energy and for a real heat pump you will need even more.

 

[Crazymechanic]

Well not being a big mathematician but still understanding physics I think that the problem with excess energy extraction from a heat pump /heat engine cycle is that nowhere in nature atleast not on this Earth you have these huge temperature differences from which you could extract a lot of energy , the temperature differences are only minimal and that's why I believe it is really not considered a viable source of energy.
Ofcourse we have huge temperatures in the mantle down below and there were proposed plans for a steam generation/electricty power plant based on that but I guess the engineering challenge and cost speaks for itself.

Not to mention that converting heat to other forms of energy isn't that efficient at all electromagnetism into other forms of energy like mechanical and heat is much more efficient way of converting different forms of energy.So I believe a heat engine is not a very efficient way to run a generator, not to mention the problems associated with running the heat engine in the first place.

This whole idea sounds to me like a self running refrigerator, but we all know that if you want to move something from point "a" to point "b" you need to input energy to do that.If you just let the hot reservoir mix with the cold one without keeping them temperature separated then all you come out is a equal temperature at both reservoirs and the heat pump being useless.

 

[Low-Q]

I'm disappointed. You give up far to easily.

I "gave up" because the explanations repeatedly given to me finally sounded reasonable.

I am open to any suggestions that might make this work, but for now (and a few hours to come) I must digest all the information that is already given.

You and me can always discuss this further in another forum.
Equations, reading explanations etc. works not that well for me. I need hands on experience in order to get a good understanding of how things work.
For now it is too expensive to buy a heat pump and a decent heat engine to test this out in practice. So I need some more time to digest all given information, as well as understand where we all disagree or misunderstand each other.

It is hard to be open minded, and be thinking outside the box, while discussing physics with "rational minded" people (No offence to anyone) who mostly do think inside the box - who is referring to most common textbooks.

I'm pretty open minded, but I understand that energy cannot be created from nowhere, nor be destroied. I try to think outside the box without violating common physics...

@DaleSpam: Only dealing with mainstream physics is a huge disadvantage for those more open minded thinkers who want answers to their problem. However, in my opinion, discussions which is all about over unity, perpetual motion, which has nothing to do in this forum, is far beyond being open minded. I think this forum should have enough headroom to allow a discussion take place between pundits and scientists. The main thing to be sure of is that we understand each other's ideas and come to a conclusion that seems rational - and even provable.

Vidar