No, not quite. Citrix originally licensed NT 3.51 and changed the windows code in order to retrofit true-multiuser capabilities and their super-thin, super-fast ICA protocol. When Microsoft noticed that the idea worked, they refused to license NT 4.0, and created their RDP protocol in a hurry. As a result, the RDP protocol was similar, but much heavier than ICA.
I remember some of our users running Citrix over dial-up. It was difficult to tell they weren't at their terminals.:-)
Let's think about this for a moment. UltraVNC is the only Windows VNC that acts like a video driver. THus it's the only one that doesn't need to poll the hell out of your computer. Thus it's the only one that gets all the screen updates right.
Fair enough. But what about a micro-stirling engines (as I suggested earlier)? They're already being used in waste heat recovery, and are far more effective in the lower power ranges. In that case the heat *is* useful.
Great. Just what I want. Greater dependence on big oil companies. It isn't enough that they're screwing me on fuel prices for my car, now they want to have a cut in providing power for my laptop and/or cell phone, too. This technology is not the answer. It's the question. "HELL NO" is the answer.
You'll forgive me, but that sounds like a heat pump. If I understand you correctly, the two heat exchangers + intermediary fluid loop are used to transfer heat from the turbine exhaust to the secondary turbine (usually a steam turbine). In short, the heat is being "pumped" to the secondary turbine.
My original question is: why can't we use a smaller heat pump (e.g. a thermoelectric pump) to replace the fluid pump?
A heat exhanger is not a form of a heat pump.
You are correct. A heat exchanger is a component of a phase change heat pump. Sorry for the confusion. I'm just trying to grasp what you're getting at.
When people talk about heat sources and heat sinks, what exactly do you think those are?
A heat source is anything that generates heat, whereas a heat sink is a device for channeling and dissipating heat.
A heat pump (as I understand it) is a a device that forces heat in directions that it wouldn't normally flow. The physics behind heat pumps are what make refrigeration possible.
Now when we're talking about heat exchangers, my understanding is that we are talking about devices which exchange heat between fluids. Thus a heat exchanger is a form of a heat pump, but a heat pump is not a heat exchanger. Am I wrong?
Since heat tends to flow to cooler areas in an attempt to equalize the temperature, you usually only need a proper cooling surface somewhere so as to channel the heat for use. Stirling engines are a perfect example of this as they operate as long as one side of the engine is hot and the other is cool. In fact, stirling efficiency is entirely based on the temperature differential between the two sides.
OTOH, I don't know enough about how the secondary cycles of gas turbines work to state with certainty that providing a cooling surface would solve the problem. My only point is that devices do have proper surfaces for some forms of heat recovery.
Additionally, using a secondary cycle requires not just a second flow loop, but also requires a heat exhanger to move energy from the first cycle to the second, and those generally aren't small or light.
Hmm... a heat exchanger would definitely be problematic. How about a tiny heat pump? I've seen heat pump designs that could easily fit in a microchip design like this.
I don't believe that a laptop, PDA, or most other consumer electronic item these would be so cool for would be an ideal candidate for a combined heat/power system. Laptops get hot enough running on batteries.
Not internally, but an external cooling surface could be provided.
Phones and PDAs should be fine, though. Most of their heat comes from the battery discharging. Now that I think about it, why don't we go for micro-stirling engines? They'd be WAY more efficient than these gas turbines!;-):-P
That's a good point. Hydrogen embrittlement is a serious issue with rocket engine design. I hadn't considered that it would be an issue with fuel cells. That may be why many laptop cells utilize methanol as a hydrogen storage medium.
You're not making any sense. In one breath you say that the analogy is flawed, then in the next breath you say that gas turbines and jet engines are very similar just like electric generators and motors.
???
You'll have to pardon me, but I'm quite confused by your statements.
Why do you say that gas turbines are some of the most efficient fuel to energy converters known to man? Every link I can find in a google search says otherwise.
That used to be true, but the current breed of Gas Turbines are amazingly efficient. From wikipedia:
They can be particularly efficient -- up to 60 percent -- when waste heat from the gas turbine is recovered by a conventional steam turbine in a combined cycle.
The primary issue in obtaining high efficiencies is in (as you stated) efficiently recycling the waste heat. I can only assume that the inventors would be attempting to shrink the secondary cycle along with the gas turbine. The physics really aren't all that different, so it should just be a matter of materials.
Also from the wikipedia link above:
Typical micro turbine efficiencies are 20 to 35 percent. When in a combined heat and power system, overall efficiencies of greater than 90 percent may be achieved.
The primary difference is energy density. As fuels go, petroleum is the the most energy dense fuel short of nuclear. While there are attempts to find even denser fuels, none of the alternatives that have been investigated are stable enough or safe enough for use.
Well, your cell phone only needs about a watt, a PDA about 2-10 watts, and your laptop about 20-100 watts. If you consider that cars produce kilowatts of constant power output, you should realize that the amount of exhaust shouldn't be anywhere close to what your car puts out.
In addition, these turbines will probably use something a smidge cleaner than gasoline. Even kerosine is better, but ethanol would probably rank the cleanest.
Speaking of kerosine, these turbines shouldn't even be as back as burning a kerosine lamp.:-)
1. That's pretty damned cool. Gas Turbines are some of the most efficient fuel -> energy converters known to man.
2. Saying that a Gas Turbine == a Jet Engine is a bit misleading. It's a bit like saying "Scientists have shrunk an electric motor to 4 nanmometers", then before you even finish thinking about all the MEMS devices, you read "Scientists have produced a 4 nanometer electric genertor for use in making power for MEMS devices." Still very cool, but not the same thing.
<<State of the demon??..but BSD is dead..and netcraft confirmed it. <Troll? Comone mod's mark it as redundant. My bad for not reading the previous comments but still a troll?
No offense bub, but everyone's REALLY tired of that "joke". Face it, the joke is dead. Netcraft confirmed it.
I can't read the article, so I'll just post a standard response here.
While it could use some help in the ports and upgrading department
FreeBSD does quite well in both departments. For ports, you have the option of either compiling the source via a simple "make install", or installing the binaries via "pkg_add mypackage.tgz".
For OS updates, you again have a choice. To update form sources, simply run a CVSUp and type "make buildworld; make installworld". To install from binaries, pop the latest CD in, reboot, and go through the "upgrade" instructions. I honestly haven't seen any OS do a better job in package management.:-)
Unlike the other responders to this reply, I agree that you have a strong point...
You're probably the only one, but thank you.:-)
the only problem lies in not carefully reading the GP post or my response to your post (just as many people have not carefully read your response I am now replying to)...
It may be more because the GP post was ambiguous in nature. His english was extremely difficult to parse. As a result, I interpreted his post to mean that "It's GPL, so therefore it's free." i.e. The mistaken assumption that the GPL is "viral".
This is why I mentioned trolling, as it appeared to be a pretty obvious statement by the GP, which you then turned into a contriversial statement by only highlighting half of the issue. I'm pretty sure it was an unintentional troll, but the effect was the same.
One has to be careful around here. "Troll" is a pretty strong word to throw around, especially when there's a good chance of miscommunication. It was, in fact, not my intention to troll. Merely to point out that CherryOS is still protected by copyright law, and will continue to be protected until such time that the author decides to release the source code under the GPL.
Discussions about CherryOS being released under the GPL really are independent of the issue at hand. The reason for this, is that the author has no obligation to release the source (even if he has been found in breach of contract and/or infringing on copyrights). Again, posters tend to assume a "viral" aspect to the GPL.
Looks like someone removed some of your karma, which I think is a bit extreme, considering everything you said was correct, just not in context.
Surprisingly, I don't think any of my karma went anywhere. The entire thread seems to have been mostly ignored by the mods. (Perhaps because they had difficulty in deciding who they felt was "right" or "wrong".) I'm capped either way, so I don't worry about it too much. Thank you for the sentiment, though.:-)
This is all I could find. It doesn't seem that many people are all that interested in getting it working.
Personally, I wish Sun would release NeWS. Gosling may think the code is of no use, but I consider it an important part of computing history. Not to mention that computing has been off-track for the past decade, and has only now started to pick up again as people's love affair with Microsoft has waned.
Slashdot Mirror
So basically, after all this back and forth, what you're trying to say is that you don't think a small heat pump would work very well.
:-)
Well then, glad we got that cleared up.
Thanks for sticking in there.
I thought Remote Desktop was based on Citrix?
:-)
No, not quite. Citrix originally licensed NT 3.51 and changed the windows code in order to retrofit true-multiuser capabilities and their super-thin, super-fast ICA protocol. When Microsoft noticed that the idea worked, they refused to license NT 4.0, and created their RDP protocol in a hurry. As a result, the RDP protocol was similar, but much heavier than ICA.
I remember some of our users running Citrix over dial-up. It was difficult to tell they weren't at their terminals.
I realize the best and most speedy one out of them all are actually Remote desktop that came with WindowsXP Pro and such..
:-D
You haven't tried Citrix.
Let's think about this for a moment. UltraVNC is the only Windows VNC that acts like a video driver. THus it's the only one that doesn't need to poll the hell out of your computer. Thus it's the only one that gets all the screen updates right.
Pinky, are you thinking what I'm thinking?
Fair enough. But what about a micro-stirling engines (as I suggested earlier)? They're already being used in waste heat recovery, and are far more effective in the lower power ranges. In that case the heat *is* useful.
Great. Just what I want. Greater dependence on big oil companies. It isn't enough that they're screwing me on fuel prices for my car, now they want to have a cut in providing power for my laptop and/or cell phone, too. This technology is not the answer. It's the question. "HELL NO" is the answer.
True 'dat.
Errr... Kerosene. Damn. ;-)
No, I meant kerosine. Kersene is an alternate spelling.
You'll forgive me, but that sounds like a heat pump. If I understand you correctly, the two heat exchangers + intermediary fluid loop are used to transfer heat from the turbine exhaust to the secondary turbine (usually a steam turbine). In short, the heat is being "pumped" to the secondary turbine.
My original question is: why can't we use a smaller heat pump (e.g. a thermoelectric pump) to replace the fluid pump?
A heat exhanger is not a form of a heat pump.
You are correct. A heat exchanger is a component of a phase change heat pump. Sorry for the confusion. I'm just trying to grasp what you're getting at.
And, interestingly enough, jet fuel IS kerosene.
:-)
Precisely. As I understand it, Jet Fuel differs only in some of the additives used for improving fuel efficiency in Jet Engines.
When people talk about heat sources and heat sinks, what exactly do you think those are?
A heat source is anything that generates heat, whereas a heat sink is a device for channeling and dissipating heat.
A heat pump (as I understand it) is a a device that forces heat in directions that it wouldn't normally flow. The physics behind heat pumps are what make refrigeration possible.
Now when we're talking about heat exchangers, my understanding is that we are talking about devices which exchange heat between fluids. Thus a heat exchanger is a form of a heat pump, but a heat pump is not a heat exchanger. Am I wrong?
Since heat tends to flow to cooler areas in an attempt to equalize the temperature, you usually only need a proper cooling surface somewhere so as to channel the heat for use. Stirling engines are a perfect example of this as they operate as long as one side of the engine is hot and the other is cool. In fact, stirling efficiency is entirely based on the temperature differential between the two sides.
OTOH, I don't know enough about how the secondary cycles of gas turbines work to state with certainty that providing a cooling surface would solve the problem. My only point is that devices do have proper surfaces for some forms of heat recovery.
You do realize that heat pumps use heat exchangers, right?
Umm... nooo.... Not unless my peltier is a heat exchanger.
Feel free to correct me if I'm wrong, though.
Additionally, using a secondary cycle requires not just a second flow loop, but also requires a heat exhanger to move energy from the first cycle to the second, and those generally aren't small or light.
Hmm... a heat exchanger would definitely be problematic. How about a tiny heat pump? I've seen heat pump designs that could easily fit in a microchip design like this.
I don't believe that a laptop, PDA, or most other consumer electronic item these would be so cool for would be an ideal candidate for a combined heat/power system. Laptops get hot enough running on batteries.
;-) :-P
Not internally, but an external cooling surface could be provided.
Phones and PDAs should be fine, though. Most of their heat comes from the battery discharging. Now that I think about it, why don't we go for micro-stirling engines? They'd be WAY more efficient than these gas turbines!
That's a good point. Hydrogen embrittlement is a serious issue with rocket engine design. I hadn't considered that it would be an issue with fuel cells. That may be why many laptop cells utilize methanol as a hydrogen storage medium.
You're not making any sense. In one breath you say that the analogy is flawed, then in the next breath you say that gas turbines and jet engines are very similar just like electric generators and motors.
???
You'll have to pardon me, but I'm quite confused by your statements.
Why do you say that gas turbines are some of the most efficient fuel to energy converters known to man? Every link I can find in a google search says otherwise.
That used to be true, but the current breed of Gas Turbines are amazingly efficient. From wikipedia:
They can be particularly efficient -- up to 60 percent -- when waste heat from the gas turbine is recovered by a conventional steam turbine in a combined cycle.
The primary issue in obtaining high efficiencies is in (as you stated) efficiently recycling the waste heat. I can only assume that the inventors would be attempting to shrink the secondary cycle along with the gas turbine. The physics really aren't all that different, so it should just be a matter of materials.
Also from the wikipedia link above:
Typical micro turbine efficiencies are 20 to 35 percent. When in a combined heat and power system, overall efficiencies of greater than 90 percent may be achieved.
The primary difference is energy density. As fuels go, petroleum is the the most energy dense fuel short of nuclear. While there are attempts to find even denser fuels, none of the alternatives that have been investigated are stable enough or safe enough for use.
What about the exaust?
:-)
Well, your cell phone only needs about a watt, a PDA about 2-10 watts, and your laptop about 20-100 watts. If you consider that cars produce kilowatts of constant power output, you should realize that the amount of exhaust shouldn't be anywhere close to what your car puts out.
In addition, these turbines will probably use something a smidge cleaner than gasoline. Even kerosine is better, but ethanol would probably rank the cleanest.
Speaking of kerosine, these turbines shouldn't even be as back as burning a kerosine lamp.
* AKAImBatman takes a polite bow
=)
1. That's pretty damned cool. Gas Turbines are some of the most efficient fuel -> energy converters known to man.
2. Saying that a Gas Turbine == a Jet Engine is a bit misleading. It's a bit like saying "Scientists have shrunk an electric motor to 4 nanmometers", then before you even finish thinking about all the MEMS devices, you read "Scientists have produced a 4 nanometer electric genertor for use in making power for MEMS devices." Still very cool, but not the same thing.
<<State of the demon??..but BSD is dead..and netcraft confirmed it.
<Troll? Comone mod's mark it as redundant. My bad for not reading the previous comments but still a troll?
No offense bub, but everyone's REALLY tired of that "joke". Face it, the joke is dead. Netcraft confirmed it.
I can't read the article, so I'll just post a standard response here.
:-)
While it could use some help in the ports and upgrading department
FreeBSD does quite well in both departments. For ports, you have the option of either compiling the source via a simple "make install", or installing the binaries via "pkg_add mypackage.tgz".
For OS updates, you again have a choice. To update form sources, simply run a CVSUp and type "make buildworld; make installworld". To install from binaries, pop the latest CD in, reboot, and go through the "upgrade" instructions. I honestly haven't seen any OS do a better job in package management.
Unlike the other responders to this reply, I agree that you have a strong point...
:-)
:-)
You're probably the only one, but thank you.
the only problem lies in not carefully reading the GP post or my response to your post (just as many people have not carefully read your response I am now replying to)...
It may be more because the GP post was ambiguous in nature. His english was extremely difficult to parse. As a result, I interpreted his post to mean that "It's GPL, so therefore it's free." i.e. The mistaken assumption that the GPL is "viral".
This is why I mentioned trolling, as it appeared to be a pretty obvious statement by the GP, which you then turned into a contriversial statement by only highlighting half of the issue. I'm pretty sure it was an unintentional troll, but the effect was the same.
One has to be careful around here. "Troll" is a pretty strong word to throw around, especially when there's a good chance of miscommunication. It was, in fact, not my intention to troll. Merely to point out that CherryOS is still protected by copyright law, and will continue to be protected until such time that the author decides to release the source code under the GPL.
Discussions about CherryOS being released under the GPL really are independent of the issue at hand. The reason for this, is that the author has no obligation to release the source (even if he has been found in breach of contract and/or infringing on copyrights). Again, posters tend to assume a "viral" aspect to the GPL.
Looks like someone removed some of your karma, which I think is a bit extreme, considering everything you said was correct, just not in context.
Surprisingly, I don't think any of my karma went anywhere. The entire thread seems to have been mostly ignored by the mods. (Perhaps because they had difficulty in deciding who they felt was "right" or "wrong".) I'm capped either way, so I don't worry about it too much. Thank you for the sentiment, though.
This is all I could find. It doesn't seem that many people are all that interested in getting it working.
Personally, I wish Sun would release NeWS. Gosling may think the code is of no use, but I consider it an important part of computing history. Not to mention that computing has been off-track for the past decade, and has only now started to pick up again as people's love affair with Microsoft has waned.