In mechanical engineering your typical quality heat pump / refrigeration unit is over unity in respect to the physical work put in.
Mechanical Work + Ambient Energy(Heat, fluid as exchange medium) = Output Energy(Heat, fluid as exchange medium)
No violation of conservation of energy but more energy put out than in.
Note the extraction of ambient energy results in observed cooling
Can one not use this to create a self sustaining loop?
My understanding is that efficiency losses would be too high from a thermal/mechanical system..carnot efficiency etc.
Has or could a similar concept be made using electronics? Electric mediums are far more efficient.
E in + E ambient (Electric/Magnetic transfer medium) = E out (Electric/Magnetic transfer medium)
E out (Electric/Magnetic transfer medium) - E in - E losses = Extracted useful electrical energy
Is it out there?
Firstly, you're right about efficiency. I believe the conversion efficiency of heat engines like the stirling engine is about 30 percent. Electrically, using present day thermo-converters this actually gets much worse, though there is plenty of research going on to improve this. A recent patent by Lonnie Johnson suggests that a big step forward has already been achieved.
Secondly, entropy is an important part of the picture. The sum of the entropy inside and outside the heated area must tend towards a higher value. The amount of "order" being provided to the system by collecting the heat in one place is more than made up for by the amount of "disorder" brought about by releasing the driving energy from its source. Clearly such a requirement can never be self-running.
What is interesting, is that the larger part of domestic energy consumption is used for heating and that even with present day technology, we can do more to benefit from heat pumps. Already there are commercial water heaters that use the same heat pump principles as air conditioners. Some manufacturers have even got round to keeping the system efficient when the ambient temperature outside is very low.
I predict that if the next generation of solid state electronic heat pumps reach the predicted level of performance (close to the theoretical maximum) we will have super efficient electric kettles for the summer that can provide the user with a cool breeze.
Regards
Joseph
I was pondering the advantage of using a heat pump to heat the hot chamber of a stirling engine, and may have stumbled on the proof why the stirling engine efficiency can never exceed one third.
Given that the efficiency of electric motors is easily over 90 percent, no one would normally consider using electric heating for the hot end of a stirling engine. But what if you would heat it using a heat pump? Better still, what if you use the heat pump to both heat the hot end and cool the cool end of the machine?
The diagram included shows this schematically. A and B are two well insulated heat reservoirs. The heat pump transfers heat from B to A, while the stirling engine runs on the heat as it travels down the temperature gradient from A to B. After some time a steady state is reached where the temperature of each reservoir is constant. When this happens the amount of heat Q being pumped by the heat pump equals the amount of heat Q passing through the stirling engine. Now, we know from experience that the amount of heat Q transferred by the heat pump can, at best, be three times the driving energy. (If it has to work against a high temperature difference, this value can be much less). So for the principle of conservation of energy to hold true, the mechanical output of the stirling engine can only be one third of the heat flowing through.
Regards
Joseph
www.io.com/~frg : MEMS-TAR = electron-pump
when you want to analogize then read and think about the Torribio Bellocq-publications,
"virtually use" the www.larbombas.pt/ ( real commercial available !) heatpump ,optimize the
performance of the e-pump-motor with a softdriver
and "virtually use an" efficient heat-engine ,
at least calculate by yourself which C.O.P.-relations you will need for each energie-transformation to
get your wished overunity-effect !
Best trial success
CdL
So mechanical energy has the big role in any heat pumps.
_________________
Programmable Thermostats (http://www.prothermostats.com/)
I agree it is very important to know you engine. We absolutely agree.
_________________
Refrigerator filter (http://www.filter-outlet.com)
The JTEC heat pump is already here!
http://www.johnsonems.com/?q=node/2
Quote from: lumen on August 06, 2009, 09:11:42 AM
The JTEC heat pump is already here!
http://www.johnsonems.com/?q=node/2
This website has vanished, damn! ... looks like the hoods have got him already!
Joseph
Hope this helps.
Google Cached Pages:
http://www.google.com/search?hl=en&safe=off&num=100&newwindow=1&q=site%3Ajohnsonems.com&aq=f&oq=&aqi=
WayBack Machine Archives:
http://web.archive.org/web/*/http://www.johnsonems.com/ (http://web.archive.org/web/*/http://www.johnsonems.com/)
Sadly, an asterisk cannot be used in any URL with this forum engine,
you will have to copy/paste to your browsers address line instead.
I have included the regular and advanced links for your use too.
Reference Links:
http://www.archive.org/index.php
http://web.archive.org/collections/web/advanced.html
Of course, Lonnie G. Johnson can be contacted
in one of his other ventures like this one.
(Until this website is up again.)
http://www.excellatron.com/team.htm
UPDATE:
I edited the above using the URL tags to fix it ...
Test 1:
I'll quoted myself, as a URL/Asterisk test.
Quote from: CompuTutor on November 22, 2009, 11:15:45 AM
http://web.archive.org/web/*/http://www.johnsonems.com/
Nope, that didn't work either...
Test 2:
I'll try the URL tag here:
http://web.archive.org/web/*/http://www.johnsonems.com/ (http://web.archive.org/web/*/http://www.johnsonems.com/)
Thats more like it. :)
Where is the button to delete ones own post btw ???
It seems it should be parked here:
http://63.243.48.36/
Many people are looking for alternative methods for heating and cooling their homes. When comparing the different heat pumps, it is helpful to understand heat pump efficiency. This article will address this issue.
Macerator Pumps (http://www.plumbarena.co.uk/category/pumps-macerators/)
A heatpump is already an overunity device but outputs heat. If that could be converted into electrical power you would have a selfrunning device that would produce electrical energy out of thermal energy. The problem is the losses of its components.
But what are losses?
Almost all losses are heat!
So what you need to do is to keep the losses in the system.
All it needs is a feedback loop that collects them and feeds them back to the heatpump.
That is the basic idea of my invention.
Check the presentation in the download area on http://farislandllc.com and let me know what you think.
Quote from: RedEagle on June 26, 2013, 08:32:38 PM
A heatpump is already an overunity device but outputs heat. If that could be converted into electrical power you would have a selfrunning device that would produce electrical energy out of thermal energy. The problem is the losses of its components.
But what are losses?
Almost all losses are heat!
So what you need to do is to keep the losses in the system.
All it needs is a feedback loop that collects them and feeds them back to the heatpump.
That is the basic idea of my invention.
Check the presentation in the download area on http://farislandllc.com and let me know what you think.
FYI, heat pumps are not "overunity".
Heat pumps are definitely not overunity, and if you try and put any of this calculated COP to any work it will not succeed. Many people have tried.
Kind Regards
Quote from: picowatt on June 26, 2013, 09:36:41 PM
FYI, heat pumps are not "overunity".
they are sure not in the means that they could actually produce energy, but definatly output more heat than electrical power is put in.
So its a point of view. If you consider the taken thermal energy as input too its just unity in best case.
Besides that many people tried to fly and got laughed at and told that many people tried it before and never succeeded... until someone did succeed.
Read my patent and proof me wrong, that will save me a lot of money.
Red Eagle
sadly I do not have to prove you wrong as you can not demonstrate a working prototype that would pass third party review.
The last two projects I was involved in regarding what you are trying to achieve sadly resulted in falling over when it came to the practical demonstrations, and they spent a lot of money and even involved a University (that always amuses me)
However I encourage you to continue your work, as I do all researchers you might only be 998 light bulbs away.
Kind Regards
Mark
Quote from: RedEagle on June 26, 2013, 10:52:20 PM
they are sure not in the means that they could actually produce energy, but definatly output more heat than electrical power is put in.
So its a point of view. If you consider the taken thermal energy as input too its just unity in best case.
Besides that many people tried to fly and got laughed at and told that many people tried it before and never succeeded... until someone did succeed.
Read my patent and proof me wrong, that will save me a lot of money.
All I said was that a heatpump is not overunity. I don't recall "laughing" about anything.
Heat pumps are "pumps". Lots of inefficiencies. Electrical losses, pumping losses, exchanger losses, etc.
PW
Mark,
the prototype is what I'm working on. This will sure take time and money and I sure will need help to build it.
But so far nobody was able to tell me a reason why this should not work and in fact its not possible to destroy energy so it has to be somewhere after being extracted from the environment. I've seen a lot of discussion here on e.g. permanent magnet motors but have never seen one running or have read or heard any explaination on how it should work. But I do respect people trying to achieve what I think is not possible. I try to keep my mind open to any idea and won't say something IS impossible just because I think it is.
You are right, you don't have to proof me wrong, but at least I have an explanation where the energy comes from.
I just ask to consider my idea like any other in this forum and if anyone has a reason why it can not work and can explain where the energy is lost, I will stop all efforts to build that generator.
So please read the documents on my page before you say it can't work.
Regards
Red
Quote from: picowatt on June 26, 2013, 11:14:25 PM
All I said was that a heatpump is not overunity. I don't recall "laughing" about anything.
Heat pumps are "pumps". Lots of inefficiencies. Electrical losses, pumping losses, exchanger losses, etc.
PW
That "laughing" did not mean you or anyone else here, its just a historical fact. To be honest watching some videos about the early tries to fly still makes us laugh today ;)
Efficiency is a point of view. If you take a lightbulb its just 5% efficient and has 95% losses. But consider it a heater its 95% efficient.
A heat pump sure has losses, but these losses are set free as heat to almost 100%. so are they really losses if the purpose of the pump is to produce heat?
It really just depends on how you look at it.
Quote from: RedEagle on June 26, 2013, 11:35:58 PM
That "laughing" did not mean you or anyone else here, its just a historical fact. To be honest watching some videos about the early tries to fly still makes us laugh today ;)
Efficiency is a point of view. If you take a lightbulb its just 5% efficient and has 95% losses. But consider it a heater its 95% efficient.
A heat pump sure has losses, but these losses are set free as heat to almost 100%. so are they really losses if the purpose of the pump is to produce heat?
It really just depends on how you look at it.
A gasoline IC engine would have an incredible "COP" if its heat source did not have to be factored in...
PW
Quote from: RedEagle on June 26, 2013, 11:22:59 PM
Mark,
the prototype is what I'm working on. This will sure take time and money and I sure will need help to build it.
But so far nobody was able to tell me a reason why this should not work and in fact its not possible to destroy energy so it has to be somewhere after being extracted from the environment. I've seen a lot of discussion here on e.g. permanent magnet motors but have never seen one running or have read or heard any explaination on how it should work. But I do respect people trying to achieve what I think is not possible. I try to keep my mind open to any idea and won't say something IS impossible just because I think it is.
You are right, you don't have to proof me wrong, but at least I have an explanation where the energy comes from.
I just ask to consider my idea like any other in this forum and if anyone has a reason why it can not work and can explain where the energy is lost, I will stop all efforts to build that generator.
So please read the documents on my page before you say it can't work.
Regards
Red
I notice the patent application make no claim of 'over-unity' operation. It will work of course as long as the SUPPLY of heat energy is maintained and is able to exhaust to a reservoir at a lower temperature than the inlet. As such you have a heat engine where the efficiency is determined by the difference in temperature between the hot and cold reservoirs.
However, the dream of using this to run just on ambient energy is a pipe dream. The 2nd Law of thermodynamics precludes being able to create an maintaining a temperature differential without requiring external energy input. At best your mechanism could serve to increase the efficiency of the heat engine by cooling the exhaust, much like an intercooler does.
Hello Larsth,
"In mechanical engineering your typical quality heat pump / refrigeration unit is over unity in respect to the physical work put in.|'
Carbon - CO2 is a natural refrigerant. You be on the ball, rid your work of the friction found in solid piston devices, and go turbine.
Absorption fridge boiler heats Refrigerant to high head pressure blocked by a plate with tiny hole. Heat is energy and so much energy is taken getting through the tiny hole the Refrigerant comes out the other side cold.
A turbine runner will obtain momentum by hot gas force, it will allow that gas to pass into a cooling chamber where the gas again becomes liquid, it will convey liquid into a boiler.
Any liquid may be used however a personal preference is for Carbon-CO2 and its super high pressure forces for such little heat, commencing upward from -40*Celsius.
Peter
First of all. Heat pumps are not over unity machines. They move heat from one source to another. It's like shuffeling coal (Which contains lots of stored energy) from one place and into an oven.
If you try to run a stirling engine with a heat pump, the engine will transport cold air into the hot reservoir of the heat pump. The heat pump can transfer heat from a hot reservoir into a cold reservoir, and not from a cold reservoir to another cold reservoir.
If you want to make a working heat pump/stirling engine, you need a third reservoir that is insolated from the already cold and hot reservoir. The heat pump and the stirling engine must have one common cold reservoir, but have separate hot reservoirs.
The COP of a heat pump is often misunderstood. If it has a COP of 5, it means the pump can TRANSPORT 5 parts of energy with 1 part of energy input. It does not PRODUCE 5 parts of energy from 1 part of energy input. An ideal heat pump would have a COP of infinity, because transporting energy from one source to another does in fact not require energy at all. However, a heat pump suffer from losses because the pump must fight against a pressure difference between the cold and the hot radiator. The pump must compress the hot working fluid so it can deliver heat indoor. As the liquid working fluid expands it releases its heat energy and gets very cold. This gas will now be warmed up by the outdoor air or the ground. It will pick up heat only if the cold gas is colder than the outdoor air or ground.
So if you connect a stirling engine to a heat pump, the net result will be that the energy input continue to heat up both reservoirs, and the heat pump "stalls". If you disconnect the input energy, both reservoirs will gradually cool down so both heat pump and stirling engine finally stops.
Vidar
Quote from: LibreEnergia on June 27, 2013, 01:24:00 AM
I notice the patent application make no claim of 'over-unity' operation. It will work of course as long as the SUPPLY of heat energy is maintained and is able to exhaust to a reservoir at a lower temperature than the inlet. As such you have a heat engine where the efficiency is determined by the difference in temperature between the hot and cold reservoirs.
However, the dream of using this to run just on ambient energy is a pipe dream. The 2nd Law of thermodynamics precludes being able to create an maintaining a temperature differential without requiring external energy input. At best your mechanism could serve to increase the efficiency of the heat engine by cooling the exhaust, much like an intercooler does.
You're right, I don't claim overunity and thus of course need constant energy supply. In a closed room the engine could not run eternally.
Also the generator will need energy to get the process started, actually internally it constantly needs energy to keep the temperature difference.
I just claim, that the amount of energy it produces is higher than what it needs to keep running.
So neither the 1st nor the 2nd law of thermodynamics is violated.
Every single process in the generator is known and can be calculated.
Considering the losses it also would not work without the feedback, but that is one claim of my patent.
@Low-Q
I totally agree with you.
keeping the fridge door open does not cool the kitchen, it warms it up.
And absolutely right, to make it work you need 3 reservoirs which I take in respect as you can see in my presentation. (the extended Carnot process)
The picture of that process just explains why it can work, it does not show the actual process in the generator, which is more complicated and involves more different energy levels.
Additionally the feedback provides a cascading effect to increase the heat.
The presentation was made for people with no technical skills, so I tried to keep it simple and just explain the basic principle.
This also means that the description is missing two parts.
For your convenience I add this presentation as pdf to this post.
It is the same that can be found on my webpage http://farislandllc.com
Quote from: markdansie on June 26, 2013, 10:35:30 PM
Heat pumps are definitely not overunity, and if you try and put any of this calculated COP to any work it will not succeed. Many people have tried.
Kind Regards
Hi to All,
Heat pumps, and all refrigeration systems take advantage of peculiar way refrieration medium ( commonly called Freons) behaves.Efficiently absorbs and releases heat from surrounding.It is comon to all gases, but man engineered a special gases that do it very efficiently. Basically, refrigerant when going from liquid state to vapour ( on expansion device) vapour has low temperature- so it "sucks" heat from surounding.Then, when compessed -refrigerant "gives off" that heat to other cooling medium, like water or air ( in condenser). It also coud be explained by physics of entrophy- different states of entrophy ( or like some says " order of matter"), requires different energy levels.
A heat pump is a device, that by the help of efficient gas and cost of 1 unit of electical energy- converts large amount of low grade ( ambient) heat into smaller amount of "high grade" heat.
A heat pump is COP>1 device, for 1 unit of electrical energy, gives a few units of heat energy.The only difference from calling this OU device is- we know from where energy comes. I would say, a OU device is a COP>1 device where we don't know from where extra energy comes. Energy can't be created or destroyed.Every OU device only "converts" one state of energy to another state of energy.
Heat pump is a very efficient device, that converts large amount of low temperature heat, into smaler amount of high temperature heat by help of electric energy.
Regards
Pix
Quote from: RedEagle on June 27, 2013, 07:47:51 AM
@Low-Q
I totally agree with you.
keeping the fridge door open does not cool the kitchen, it warms it up.
And absolutely right, to make it work you need 3 reservoirs which I take in respect as you can see in my presentation. (the extended Carnot process)
The picture of that process just explains why it can work, it does not show the actual process in the generator, which is more complicated and involves more different energy levels.
Additionally the feedback provides a cascading effect to increase the heat.
The presentation was made for people with no technical skills, so I tried to keep it simple and just explain the basic principle.
This also means that the description is missing two parts.
For your convenience I add this presentation as pdf to this post.
It is the same that can be found on my webpage http://farislandllc.com (http://farislandllc.com/)
To RedEagle,
I would say a better solution o convert heat into electricity by use of refrigerants is Organic Rankine Cycle.It is like a steam driven turbine- the difference is: water has to be heated to high temperatures to create a steam with parameters suitable to drive turbine connected to generator.Refrigerant does the same but at much lower temeratures, waste process heat or even ambient heat could be used in this cycle. It's like inverted refrigerator where compresor is replaced by expander.
Simply explaining- refrigerant has different pressure at different temperatures.If we heat liquid refrigerant by-for example solar panel to 70 deg C, it will have let's say 26 Bar pressure. Then if we put cooler into the lake water of 20 degC temperature, refrigerant will have let's say 8 bar pressure at that temperature. So, we have 18 bar pressure difference. If we put expander in between, then we will have a lot of power to drive generator. System is closed loop, heater, expander and condenser has to be properly calculated for refrigerant mass flow.Expander could be done from scroll, vane of screw compressors. A lot of such systems are already in use and gaining more attention.System will work as long, as there is temperature difference.
I am designing my expander, it will be something completly new.
Regards,
Pix
Quote from: RedEagle on June 27, 2013, 07:47:51 AM
For your convenience I add this presentation as pdf to this post.
It is the same that can be found on my webpage http://farislandllc.com (http://farislandllc.com)
Interesting document. The system with the recycled input energy you presented is much like one I have been thinking of, expect I want to use gerotary compression pumps. These pumps does not need a million RPM to compress the working fluid and its efficiency is high already at low RPM. The expansion walve is replaced by a gerotary turbine, but its capacity must be less than the compressor. This will create an imbalance in pressure which is what I want. A 5 to 1 compression will recycle 20% of the energy supplied to the compressoin pump.
A plausible way to not using energy at all to compress and expand the working fluid is something I am working on. If this idea works out the heat pump would have a COP of way more than traditional heat pumps - even a lot more than industrial heat pumps.
I will (some day) post the idea somewhere at this site so I can have some inputs on cons and pros.
Vidar
Quote from: Low-Q on June 27, 2013, 06:38:58 AM
First of all. Heat pumps are not over unity machines. They move heat from one source to another. It's like shuffeling coal (Which contains lots of stored energy) from one place and into an oven.
[size=78%]The COP of a heat pump is often misunderstood. If it has a COP of 5, it means the pump can TRANSPORT 5 parts of energy with 1 part of energy input. It does not PRODUCE 5 parts of energy from 1 part of energy input. An ideal heat pump would have a COP of infinity, because transporting energy from one source to another does in fact not require energy at all. However, a heat pump suffer from losses because the pump must fight against a pressure difference between the cold and the hot radiator. The pump must compress the hot working fluid so it can deliver heat indoor. As the liquid working fluid expands it releases its heat energy and gets very cold. This gas will now be warmed up by the outdoor air or the ground. It will pick up heat only if the cold gas is colder than the outdoor air or ground.[/size]
Vidar
Great explanation, yet so many do not understand this
Mark
Quote from: markdansie on June 27, 2013, 05:20:45 PM
Great explanation, yet so many do not understand this
Mark
"
Ere many generations pass, our machinery will be driven by a power obtainable at any point of the universe.[/size]
This idea is not novel. Men have been led to it long ago by instinct or reason; it has been expressed in many ways, and in many places, in the history of old and new. We find it in the delightful myth of [/size]
Antheus (http://en.wikipedia.org/wiki/Antaeus)[/font][/size]
, who derives power from the earth; we find it among the subtle speculations of one of your splendid mathematicians and in many hints and statements of thinkers of the present time. [/size]
Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature.[/size]
[/size]
"Experiments With Alternate Currents Of High Potential And High Frequency" (February 1892)[/li]
[li][/size]
When you take a Magnifying Transmitter from a Tesla or ... , out of the Earth's atmosphere, not working anymore!
When you take a Hubbart coil out of the Earth's (frequency) atmosphere, out of order.
When you let the Heat-Pump in his complete configuration, it will work, just build!
---------------------
A Heat-Pump is not only its mechanical device, the device "Heat-Pump "is only complete with the Cold and Hot available, and is working, but only if you want, grant or can see the overall view.
Best like explained by others before: CO2, Ammonia, Propaan or ...........
----------------------
Otherwise you also can say that a Stirling device is nothing, if you cut of the source's from cold and Hot?
Or a Solar panel, without a SUN!
Verschillende mensen zouden echt naar haar, in Zuid Afrika moeten verhuizen ;-((
Als je het licht niet wil zien, dan is het donker!
Hugz, XJ
Quote from: pix on June 27, 2013, 09:11:34 AM
To RedEagle,
I would say a better solution o convert heat into electricity by use of refrigerants is Organic Rankine Cycle.It is like a steam driven turbine- the difference is: water has to be heated to high temperatures to create a steam with parameters suitable to drive turbine connected to generator.Refrigerant does the same but at much lower temeratures, waste process heat or even ambient heat could be used in this cycle. It's like inverted refrigerator where compresor is replaced by expander.
Simply explaining- refrigerant has different pressure at different temperatures.If we heat liquid refrigerant by-for example solar panel to 70 deg C, it will have let's say 26 Bar pressure. Then if we put cooler into the lake water of 20 degC temperature, refrigerant will have let's say 8 bar pressure at that temperature. So, we have 18 bar pressure difference. If we put expander in between, then we will have a lot of power to drive generator. System is closed loop, heater, expander and condenser has to be properly calculated for refrigerant mass flow.Expander could be done from scroll, vane of screw compressors. A lot of such systems are already in use and gaining more attention.System will work as long, as there is temperature difference.
I am designing my expander, it will be something completly new.
Regards,
Pix
This has some interesting thoughts.
Though I'm talking about water in the presentation, the patent just mentions a luiqid medium. I think water will work and its easy to get, but it will have some probs like when its freezing outside. so other fluids may work way better and thus decrease starting time and size of the machine.
Anyway, if I get the prototype to work with water, then I'm sure it will also work with a refrigerant.
Quote from: Low-Q on June 27, 2013, 05:05:17 PM
Interesting document. The system with the recycled input energy you presented is much like one I have been thinking of, expect I want to use gerotary compression pumps. These pumps does not need a million RPM to compress the working fluid and its efficiency is high already at low RPM. The expansion walve is replaced by a gerotary turbine, but its capacity must be less than the compressor. This will create an imbalance in pressure which is what I want. A 5 to 1 compression will recycle 20% of the energy supplied to the compressoin pump.
A plausible way to not using energy at all to compress and expand the working fluid is something I am working on. If this idea works out the heat pump would have a COP of way more than traditional heat pumps - even a lot more than industrial heat pumps.
I will (some day) post the idea somewhere at this site so I can have some inputs on cons and pros.
Vidar
That sounds very interesting.
I thought about compressorturbine because it can compress a large amount of air compared to its size.
For my calculations I estimated 5 bar pressure, but since I recycle losses and therefore have preheated air the recycled energy of the expansion may be less than 20%.
Expansion from 5 bar compressed air will cool it down by 90°C whereas in the example in the presentation I'm only expecting 10°C.
One yet unsolved problem will be around 0-10°C environment temperature since moisture will build up ice.
I think that could be solved by using a teflon coated expansion turbine.
Does not matter for the prototype though.
Earlier work which may be of interest. Heat is energy. Hot high pressure refrigerant-CO2 is made cold by its giving up energy to get past the restriction point. A turbine is as effective in such as a plate with tiny hole. CO2 phase changes from ice to gas at -40*C . It has an enormous energy spike +30* to +100*C.
Thx a lot for the suggestion.
I think CO2 might be a good alternative to the water I'm going to use for the prototype.
All it would need is to keep the pressure in that circuit in a range that gives me a liquid in the normal outside temperatur range.
That should be possible.
I was also thinking about some alcohols before but dropped that because it's highly flameable.
"All it would need is to keep the pressure in that circuit in a range that gives me a liquid in the normal outside temperatur range."
CO2 is an oddity. It heats from Ice to Gas, Gas to Liquid, Liquid to Gas, Gas acting like Liquid and having floating Ice. Trans critical temperatures may best suit your purposes.