Discussion
https://www.epicam.co.uk/epiqair.php
interested in seeing how this would work, a small liquefied engine linked to an alternator producing electricity to drive a vehicle and or recharge a battery. were looking at ways to recharge batteries and if something like this could be created then it could provide the answer. the engine running at a set speed providing the optimum generation that is then stored into batteries. electricity being available to move the car when required.
fill up either at home with a home located liquefier, or at a filling station. air being used and then returned to the atmosphere ?
yes not as efficient as carbon fuels but still better than burring them.
interested in seeing how this would work, a small liquefied engine linked to an alternator producing electricity to drive a vehicle and or recharge a battery. were looking at ways to recharge batteries and if something like this could be created then it could provide the answer. the engine running at a set speed providing the optimum generation that is then stored into batteries. electricity being available to move the car when required.
fill up either at home with a home located liquefier, or at a filling station. air being used and then returned to the atmosphere ?
yes not as efficient as carbon fuels but still better than burring them.
The problem these days is that "could" has almost entirely been replaced by "should" when it comes to any descision process for new technology!
Back in the day, we were limited by technology and manufacturing, and so often the only thing you could do was technology limited. Today, realistically, there is almost no limit to our purely technological capability, thanks to incredible mastery of material science, understanding of physcis, and incredible assistance with all design and development activities provided by computer aided design.
No today, what a lot of people seem to miss is that being able to do something does not automatically make it sensible to actually do it! Limitations today are primarily financial, marketing and competition (marketplace) limited imo!
Back in the day, we were limited by technology and manufacturing, and so often the only thing you could do was technology limited. Today, realistically, there is almost no limit to our purely technological capability, thanks to incredible mastery of material science, understanding of physcis, and incredible assistance with all design and development activities provided by computer aided design.
No today, what a lot of people seem to miss is that being able to do something does not automatically make it sensible to actually do it! Limitations today are primarily financial, marketing and competition (marketplace) limited imo!
Okay..... how long to charge a battery ? imagine putting in liquidified air and having that run an engine that charges the battery. No long hook up to charge ? quick refuel with air and off we go. that little air engine working away and charging the battery and driving the electric motors while you go.
Liquefying air is very energy intensive: industrial gas companies are among the heaviest consumers of electricity.
The "kWh content" of a fill up will be considerable. It is probably better than hydrogen but I wouldn't be surprised if it was far greater than "filling" a Tesla.
Cryogenic equipment is specialised and expensive requiring high-grade materials, insulation, etc.. This design uses very high pressures which bring their own problems. It also uses an ambient air radiator to warm the liquid air. That will ice up very quickly, especially when it rains! (Industrial gas companies use "ambairs" for this duty but usually run them duty/standby to allow for de-icing).
Then there is the issue of boil-off: unless the car has a dedicated cryogenic cooling circuit, some of the air has to be alowed to boil off to keep the tank contents cool and avoid the pressure increasing. In a small system like this, the losses would be considerable.
It would be interesting to know what would happen if the car stood unused for a while. Would the oxygen and nitrogen separate into layers in the tank? There's a significant difference in the densities, similar to that between petrol and diesel. Unless the whole system is designed to be oxygen-compatible, there could be problems.
As someone commented earlier, just because something can be built doesn't mean it should be!
The "kWh content" of a fill up will be considerable. It is probably better than hydrogen but I wouldn't be surprised if it was far greater than "filling" a Tesla.
Cryogenic equipment is specialised and expensive requiring high-grade materials, insulation, etc.. This design uses very high pressures which bring their own problems. It also uses an ambient air radiator to warm the liquid air. That will ice up very quickly, especially when it rains! (Industrial gas companies use "ambairs" for this duty but usually run them duty/standby to allow for de-icing).
Then there is the issue of boil-off: unless the car has a dedicated cryogenic cooling circuit, some of the air has to be alowed to boil off to keep the tank contents cool and avoid the pressure increasing. In a small system like this, the losses would be considerable.
It would be interesting to know what would happen if the car stood unused for a while. Would the oxygen and nitrogen separate into layers in the tank? There's a significant difference in the densities, similar to that between petrol and diesel. Unless the whole system is designed to be oxygen-compatible, there could be problems.
As someone commented earlier, just because something can be built doesn't mean it should be!
ruggedscotty said:
Okay..... how long to charge a battery ? imagine putting in liquidified air and having that run an engine that charges the battery. No long hook up to charge ? quick refuel with air and off we go. that little air engine working away and charging the battery and driving the electric motors while you go.
The problem, often missed my lots of people is that there is no problem! Ie there really isn't any real world problem with battery recharge times for the vast majority of users. The issue is the lack of charging infrastructure, and that ACTUAL problem is not solved by introducing another energy transfer medium.....(fast chargers, rated at 150 to 300kW, will charge your battery in less that 30 min, realistically, and considering that as humans we take a manditory 8 hour recharge every single day, this is really not any impedement to using an EV for most people, considering that you CAN charge your EV at home, whereas you must take your ICE somewhere else and wait)
ruggedscotty said:
Okay..... how long to charge a battery ? imagine putting in liquidified air and having that run an engine that charges the battery. No long hook up to charge ? quick refuel with air and off we go. that little air engine working away and charging the battery and driving the electric motors while you go.
There is no mention of system efficiency, why do you think that is?Rotary screw compressors are ancient technology and one of the least efficient types of compressors, typically 70% or maybe less for a small one.
Acting as a turbine that will be even lower, so more than half the energy put into the system is going to be lost to heat in the expansion and compression stages alone.
There will also be parasitic losses elsewhere in the heat exchangers, gearboxes, valves, etc, and other system elements.
Can the system capture braking energy? Probably not.
Bear in mind also that these types of mechanical systems have a high maintenance burden and will suffer from significant further efficiency decay as they age (leakage, wear, fouling, etc.)
So would you be willing to triple or quadruple your energy consumption per mile and have much higher maintenance costs compared to EV?
55palfers said:
Your best bet would be to use liquid nitrogen.
Relatively cheap and plentiful. 1 - 700 expansion ratio so lots of energy. Nice and inert too. Only drawback is -196 deg C
..ooh, and you'll be needing one of these.
Dearman engine....Relatively cheap and plentiful. 1 - 700 expansion ratio so lots of energy. Nice and inert too. Only drawback is -196 deg C
..ooh, and you'll be needing one of these.
https://dearman.co.uk/
I can't believe its still a going concern but there you go. When I was involved with companies in this kind of circle they seemed to exist basically on the teat of OLEV/TRL/Innovate UK funding. The problem being, in the transport sector, TCO is king and most of this stuff just wipes that out completely.
Anyway, the first application I had seen was the hybrid assist for a bus. They'd use the nitrogen to drive the dearman engine, coupled to the crank of the diesel engine. The "waste" LN2 would then be used to cool the cabin. In the UK I think this turned out to be not so good because the cooling wasn't needed and it consumed a lot of LN2 on a stationary launch (something a bus does a lot of). But in very hot climates like Dubai, it would have had some benefit, I think mostly because of the cabin cooling.
They also looked at fitting these to HGV trailers to perform refrigeration duties. But the problems were that it struggled to do 2 and 3 compartment cooling (different temps, like a freezer section, a chilled section and a different chilled section). I can't exactly remember what they were doing with the rotational motion from the engine in that application. Also I think there were concerns of running out of LN2 before the shift was over as well because the particular use case still required chiller operation even when the deliveries were made (collection of waste/out of date food).
But I remember people getting a bit down hearted on it because fitting of the engine to the trailer and the LN2 tanks robbed capacity from the truck and he would have had to tanker (diesel tanker) LN2 up/down to the depot to make it all viable. It just seemed a super bulky, inefficient, inconvenient way to get some "emissions free" cooling.
Looks like they've been able to develop it further though, so maybe it can be a going concern now? The reason, or part of the reason, it exists is those diesel donkey engines they fit to refirgerated trailers. Whilst the tractor unit might be an all singing all dancing Euro6, the refrigerator engine is classed as a stationary engine, so they have different (worse) emissions limits. Though even at the time, some manufacturers did offer Euro6 level refrigeration options, which went some way to nullifying the need for something like the Dearman. But of course now, the talk is of no-ICE operation within city centres and that will include upcoming Euro 7 engines.
On their site, it looks like they have a genset application. Which might make more sense. LN2 is often (IIRC) a bit of a waste gas isnt it? from making stuff like liquid O2? so there is plenty of it. If you can base a Dearman engine next to where the LN2 is made, and if you don't need it, expand it through the engine and get some power.
On the same project, or a similar one, there was a company called Tevva who were making a 7T/14T rigid delivery truck with a hybrid system (basically a range extender) and they had found a way to power the chiller units from the battery pack whilst in the city.
No idea what came of either of these projects really, because I left the company who were involved. But I didn't really like much of it.... companies getting grants and money for hare-brained ideas or the worst, having a second go at something that is already pretty much a known quantity and doesn't need researching (pure, spark ignited, natural gas powered trucks... and waitrose made them all look silly, by going and buying their own fleet of CNG trucks whilst the others got some government money to have a second try at using them. Waitrose basically did the project on their own, with their own money and made a success of it, where the consortium on the government projects got quagmired).
Edited by Otispunkmeyer on Friday 1st May 10:15
Edited by Otispunkmeyer on Friday 1st May 10:16
For those interested in how liquid air can be used as a power source, see the highview website:
https://www.highviewpower.com/technology/
Their news section gives some applications they are currently developing in other countries.
I have no connection with Highview btw, but have been in contact with Epicam for some time now. You'd be surprised with the amount of interest their particular solution has had across different industries, not just transport...
Mutton said:
For those interested in how liquid air can be used as a power source, see the highview website:
https://www.highviewpower.com/technology/
Their news section gives some applications they are currently developing in other countries.
I have no connection with Highview btw, but have been in contact with Epicam for some time now. You'd be surprised with the amount of interest their particular solution has had across different industries, not just transport...
It definitely has potential as a stort-term power storage medium on an industrial scale; it's far more energy dense than pumping water up hill and on an industrial scale probably cheaper and more reliable than batteries. I can't see it ever being worthwhile in cars though. https://www.highviewpower.com/technology/
Their news section gives some applications they are currently developing in other countries.
I have no connection with Highview btw, but have been in contact with Epicam for some time now. You'd be surprised with the amount of interest their particular solution has had across different industries, not just transport...
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