Electric cars, does everyone really think they are amazing.
Discussion
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There is little point here Tinrobot, except I am defending myself against incorrect claims of heat pumps that don't have an external heat source any higher than external air temperature are more efficient than an electrical resistance heater. An electrical resistance heater is near 100% efficient. The reason EVs don't have resistive heaters is EV packaging, parts minimisation, the fact that EVs don't feature ability to dehumidify air that is then heated to supply warmed dehumidified air to the cabin.I don't know why others make such a big deal about heat pumps, there is no advantage to them, not even in this country, not for any car anywhere, not for any EV anywhere.
SimonYorkshire said:
Donbot said:
You still don't understand how heat pumps work lol.
People don't tend to have them as the upfont cost is high and they need routing for the plumbing adding to cost.
You're wrong. I do understand, you don't. People don't tend to have them as the upfont cost is high and they need routing for the plumbing adding to cost.
I left a company that repeated 'efficiency claims' about heat pumps in the absence of hot springs etc, I doubt you did, I don't know if you would regardless of your beliefs.
Do you think it is possible to grab energy from the atmosphere? Lol. How about grabbing energy from 'the ether then even better eh?
Heat pumps work the same as aircon, exactly the same. If you have X deg C at some heat source the pump will add Y to that X deg C and deliver it to a remote point, which in the case of an EV would be the cabin. Where on an EV can you find an X that is higher than external temperature? The resistive coil in a conventional electric heater would start at X temperature anyway.
I was once asked to sell heat pumps to UK customers - I refused and left the firm because I knew their hype was full of it and I have more integrity than to even try to dupe people. I only sell what I believe in.
It's due to the high change in enthalpy of the system due to the change in state of the coolant. If it was adding Y to X it would have made studying thermodynamics easier though
Max_Torque said:
I know it's cold up North in Yorkshire Simon, but i'm pretty sure it ain't ABSOLUTE ZERO (-273.15 degC) outside!
(Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
I thought you were an engineer? (Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
Correct it isn't oKelvin here. Now explain how you can draw energy from atmospheric heat
Pmsl lol Max, I had you down as an engineer buy you just ruined that sharad! Brilliant mate, now you have the means to run vehicles for nothing, just extract the energy from the atmosphere eh?#
Couldn't make it up.
SimonYorkshire said:
Max_Torque said:
I know it's cold up North in Yorkshire Simon, but i'm pretty sure it ain't ABSOLUTE ZERO (-273.15 degC) outside!
(Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
I thought you were an engineer? (Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
Correct it isn't oKelvin here. Now explain how you can draw energy from atmospheric heat
Pmsl lol Max, I had you down as an engineer buy you just ruined that sharad! Brilliant mate, now you have the means to run vehicles for nothing, just extract the energy from the atmosphere eh?#
Couldn't make it up.
Saw two EV cars today on my travels on the Motorways a leaf and a tesla, both doing the inside lane 60 mph RA trundle , but I digress.
There is/ was a House of Commons debate on EV and autonomous cars on the the box when I came home and one point in the bill was of particular interest.
By law, each EV charging site will have to be compatible to any EV, which is very sensible. They will have to be a smart charger capable of not only charging a car but also of acting as a battery pack for the National Grid. Each smart charger will be subject to a moving electricity price set every half hour. I suppose what price you are willing to pay gets dialled into the unit, and EV "fuel" taxes can then be collected also.
The MPs were saying that this ability to use each EV car's battery as a national resource at the behest of the power companies will flatten the electricity demand curve and mean that instead of building generation capacity for the peaks, the nation can instead manage the demand using the EV battery resource. The National grid will manage this resource. EV owners will own and pay for it.
The MP used the example of using lots of renewable and Nuclear power supplied at very low marginal cost thern topping up the nations EV batteries.
So imagine one day, perhaps even a spell in winter, when there has been a cold snap but very little wind. Lots of people climb into their EV's, noticing that the prewarmers haven't come on. The battery meter hasn't moved from last night so it look like you're not going anywhere. No, in fact the battery meter has gone down since last night.
WTF.
The only people in Evs with juice are those that paid the highest cost that they had set on the smart charger. All the juice from your battery went into theirs. B'stards. Damn those rich sods at number 43.
Your wife calls you a cheapsgate. Your kids have to walk to school and hate you. You set a new top rate on your charger straight away, and watch the weather forecast like a hawk.......
You'll be looking back and wishing that you had range anxiety.
By that time I'll have a plug in hybrid ( as long as they are cheap emough on Ebay) so I'll be alright.
Might even give you a lift.
And then those poor sods who got into work, after paying over the odds overnight, have to hope their car's charger wasn't one of the thousands turned off during the day. Do you trust your finance director not to try and save a small fortune on charging staff's private cars.
Cheers,
Tony
There is/ was a House of Commons debate on EV and autonomous cars on the the box when I came home and one point in the bill was of particular interest.
By law, each EV charging site will have to be compatible to any EV, which is very sensible. They will have to be a smart charger capable of not only charging a car but also of acting as a battery pack for the National Grid. Each smart charger will be subject to a moving electricity price set every half hour. I suppose what price you are willing to pay gets dialled into the unit, and EV "fuel" taxes can then be collected also.
The MPs were saying that this ability to use each EV car's battery as a national resource at the behest of the power companies will flatten the electricity demand curve and mean that instead of building generation capacity for the peaks, the nation can instead manage the demand using the EV battery resource. The National grid will manage this resource. EV owners will own and pay for it.
The MP used the example of using lots of renewable and Nuclear power supplied at very low marginal cost thern topping up the nations EV batteries.
So imagine one day, perhaps even a spell in winter, when there has been a cold snap but very little wind. Lots of people climb into their EV's, noticing that the prewarmers haven't come on. The battery meter hasn't moved from last night so it look like you're not going anywhere. No, in fact the battery meter has gone down since last night.
WTF.
The only people in Evs with juice are those that paid the highest cost that they had set on the smart charger. All the juice from your battery went into theirs. B'stards. Damn those rich sods at number 43.
Your wife calls you a cheapsgate. Your kids have to walk to school and hate you. You set a new top rate on your charger straight away, and watch the weather forecast like a hawk.......
You'll be looking back and wishing that you had range anxiety.
By that time I'll have a plug in hybrid ( as long as they are cheap emough on Ebay) so I'll be alright.
Might even give you a lift.
And then those poor sods who got into work, after paying over the odds overnight, have to hope their car's charger wasn't one of the thousands turned off during the day. Do you trust your finance director not to try and save a small fortune on charging staff's private cars.
Cheers,
Tony
98elise said:
SimonYorkshire said:
Max_Torque said:
I know it's cold up North in Yorkshire Simon, but i'm pretty sure it ain't ABSOLUTE ZERO (-273.15 degC) outside!
(Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
I thought you were an engineer? (Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
Correct it isn't oKelvin here. Now explain how you can draw energy from atmospheric heat
Pmsl lol Max, I had you down as an engineer buy you just ruined that sharad! Brilliant mate, now you have the means to run vehicles for nothing, just extract the energy from the atmosphere eh?#
Couldn't make it up.
YOU CANNOT EXTRACT THERMAL ENERGY USING A HEAT PUMP YOU CAN ONLY ADD TO EXISTING THERMAL ENERGY IN THE SAME WAY AS YOU CAN ADD TO EXISTING THERMAL ENERGY USING A RESISTIVE ELECTRIC HEATER. OR IF YOU CAN 'EXTRACT'THERMAL ENERGY WITHOUT A COST IN ENERGY AT LEAST EQUAL TO GAINED THERMAL ENERGY CONGRATULATIONS BECAUSE YOU HAVE JUST SOLVED THE WORD ENERGY CRISIS. THE WORLD ENERGY CRISIS WAS NOT SOMETHING YOU WOULD HAVE SOLVED RUNNING VEHICLES THAT WERE POWERED BY POWER STATIONS THAT RUN ON FOSSIL FUEL. YOU MIGHT ALSO HAVE SIMULTANEOUSLY BEEN THE PRECURSOR FOR INVENTION OF NUCLEAR FUSION POWER SO CONGRATS YOU'RE NOW A BILLIONAIRE AND HAVE JUST WON AT LEAST TWO NOBLE PEACE PRIZES. NOT BAD FOR SOMEONE WHO KNOWS JACK ABOUT HEAT PUMPS.
SimonYorkshire said:
No you don't.
YOU CANNOT EXTRACT THERMAL ENERGY USING A HEAT PUMP YOU CAN ONLY ADD TO EXISTING THERMAL ENERGY IN THE SAME WAY AS YOU CAN ADD TO EXISTING THERMAL ENERGY USING A RESISTIVE ELECTRIC HEATER. OR IF YOU CAN 'EXTRACT'THERMAL ENERGY WITHOUT A COST IN ENERGY AT LEAST EQUAL TO GAINED THERMAL ENERGY CONGRATULATIONS BECAUSE YOU HAVE JUST SOLVED THE WORD ENERGY CRISIS. THE WORLD ENERGY CRISIS WAS NOT SOMETHING YOU WOULD HAVE SOLVED RUNNING VEHICLES THAT WERE POWERED BY POWER STATIONS THAT RUN ON FOSSIL FUEL. YOU MIGHT ALSO HAVE SIMULTANEOUSLY BEEN THE PRECURSOR FOR INVENTION OF NUCLEAR FUSION POWER SO CONGRATS YOU'RE NOW A BILLIONAIRE AND HAVE JUST WON AT LEAST TWO NOBLE PEACE PRIZES. NOT BAD FOR SOMEONE WHO KNOWS JACK ABOUT HEAT PUMPS.
But that's like saying you can't get electricity from the sun. If you invent a solar panel then you have solved the worlds energy crisis, congratulations.YOU CANNOT EXTRACT THERMAL ENERGY USING A HEAT PUMP YOU CAN ONLY ADD TO EXISTING THERMAL ENERGY IN THE SAME WAY AS YOU CAN ADD TO EXISTING THERMAL ENERGY USING A RESISTIVE ELECTRIC HEATER. OR IF YOU CAN 'EXTRACT'THERMAL ENERGY WITHOUT A COST IN ENERGY AT LEAST EQUAL TO GAINED THERMAL ENERGY CONGRATULATIONS BECAUSE YOU HAVE JUST SOLVED THE WORD ENERGY CRISIS. THE WORLD ENERGY CRISIS WAS NOT SOMETHING YOU WOULD HAVE SOLVED RUNNING VEHICLES THAT WERE POWERED BY POWER STATIONS THAT RUN ON FOSSIL FUEL. YOU MIGHT ALSO HAVE SIMULTANEOUSLY BEEN THE PRECURSOR FOR INVENTION OF NUCLEAR FUSION POWER SO CONGRATS YOU'RE NOW A BILLIONAIRE AND HAVE JUST WON AT LEAST TWO NOBLE PEACE PRIZES. NOT BAD FOR SOMEONE WHO KNOWS JACK ABOUT HEAT PUMPS.
Care to guess where most of the energy in the atmosphere in the form of heat comes from?
So you're saying that both Nissan and Renault completely wasted the no doubt eyewatering amount of money they invested in developing such systems specifically to give them more efficiency for use in an EV, and they should have just bunged in an electrical resistive heater like my mate's old A4 TDi has for cold winter morning starts?
No.
You are wrong.
No.
You are wrong.
Simon.
A Heat pump doesn't "extract" thermal energy. It moves thermal energy. (which is why it's called a pump and not a "heater" or "cooler".
As you are just moving heat across a boundary, the system can move more heat across that boundary than the power with which you drive it, (without breaking the laws of physics) Typically modern Heat pumps using modern refrigerants leverage the phase change energies of those refrigerants to obtain a CoP of around 3 to 1.
ie, 1kW of work can move 3kW of heat across the boundary. No heat is generated (other than that from the losses within the system) it is just moved from A to B. And because we are increasing the energy of the system, we can go AGAINST the temperature gradient.
For example, your kitchen freezer, gets it's insides down to aroud -15degC despite your kitchen being say 20 degC
You asked how can energy be extracted from ambient temp, and the answer is of course by cooling something down to less than ambient temp, at that point the heat flux is FROM the ambient media! So, if i want to take heat from a 10degC air outside, i just cool my evaporator down to 5degC and heat "magically" flows into my system!
A Heat pump doesn't "extract" thermal energy. It moves thermal energy. (which is why it's called a pump and not a "heater" or "cooler".
As you are just moving heat across a boundary, the system can move more heat across that boundary than the power with which you drive it, (without breaking the laws of physics) Typically modern Heat pumps using modern refrigerants leverage the phase change energies of those refrigerants to obtain a CoP of around 3 to 1.
ie, 1kW of work can move 3kW of heat across the boundary. No heat is generated (other than that from the losses within the system) it is just moved from A to B. And because we are increasing the energy of the system, we can go AGAINST the temperature gradient.
For example, your kitchen freezer, gets it's insides down to aroud -15degC despite your kitchen being say 20 degC
You asked how can energy be extracted from ambient temp, and the answer is of course by cooling something down to less than ambient temp, at that point the heat flux is FROM the ambient media! So, if i want to take heat from a 10degC air outside, i just cool my evaporator down to 5degC and heat "magically" flows into my system!
Max_Torque said:
I know it's cold up North in Yorkshire Simon, but i'm pretty sure it ain't ABSOLUTE ZERO (-273.15 degC) outside!
(Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
Yeah Max. Why don't you try fitting a heat pumps evaporator to a heat pump at 100 Kelivn and seeing if any hot air blows out of the condensor. Let us know if the heat pump is any more energy efficient than a resistive coil. If it is more efficient than a heated coil, then heck, brilliant, now you could have a chain of heat pumps with each one's evaporator connected to the other's condensor and you too have solved the world energy crisis and are due a few noble peace prizes and a £fe billion. But in the meantime let is know if you find some way pf plumbing the evaporator of a moving EV to a hot spring in the UK. Don't try and tell anyone you're some sort of engineer in future. Show this one to your mates lol. (Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
SimonYorkshire said:
98elise said:
SimonYorkshire said:
Max_Torque said:
I know it's cold up North in Yorkshire Simon, but i'm pretty sure it ain't ABSOLUTE ZERO (-273.15 degC) outside!
(Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
I thought you were an engineer? (Which is precisely how cold it has to be for their to be NO HEAT.......)
'#simonsays
Correct it isn't oKelvin here. Now explain how you can draw energy from atmospheric heat
Pmsl lol Max, I had you down as an engineer buy you just ruined that sharad! Brilliant mate, now you have the means to run vehicles for nothing, just extract the energy from the atmosphere eh?#
Couldn't make it up.
YOU CANNOT EXTRACT THERMAL ENERGY USING A HEAT PUMP YOU CAN ONLY ADD TO EXISTING THERMAL ENERGY IN THE SAME WAY AS YOU CAN ADD TO EXISTING THERMAL ENERGY USING A RESISTIVE ELECTRIC HEATER. OR IF YOU CAN 'EXTRACT'THERMAL ENERGY WITHOUT A COST IN ENERGY AT LEAST EQUAL TO GAINED THERMAL ENERGY CONGRATULATIONS BECAUSE YOU HAVE JUST SOLVED THE WORD ENERGY CRISIS. THE WORLD ENERGY CRISIS WAS NOT SOMETHING YOU WOULD HAVE SOLVED RUNNING VEHICLES THAT WERE POWERED BY POWER STATIONS THAT RUN ON FOSSIL FUEL. YOU MIGHT ALSO HAVE SIMULTANEOUSLY BEEN THE PRECURSOR FOR INVENTION OF NUCLEAR FUSION POWER SO CONGRATS YOU'RE NOW A BILLIONAIRE AND HAVE JUST WON AT LEAST TWO NOBLE PEACE PRIZES. NOT BAD FOR SOMEONE WHO KNOWS JACK ABOUT HEAT PUMPS.
In simple terms the electrical energy (work) is used to extract heat energy from the atmosphere. This will typically be multiples of the electrical energy consumed.
That is why it's called a heat pump, and that's why it's more efficient that a resistance heater.
SimonYorkshire said:
I do write long posts, this is a discussion involving intertwining points which often makes it necessary to talk different points in the same post. I don't agree this makes readability more difficult, on the contrary I think it aids readability.
Forgive the off topic discussion, but this just isn't true.Don't take my word for it; google how to make text more readable.
As for pumps, of course you pump heat from an area of low concentration to an area of high concentration. That's the whole point. You don't need pumps to go down a heat gradient: That's called Opening The Doors And Windows In Winter. It's been 20 years since I did A level physics and even I know you're not right on that score.
Max_Torque said:
Simon.
A Heat pump doesn't "extract" thermal energy. It moves thermal energy. (which is why it's called a pump and not a "heater" or "cooler".
As you are just moving heat across a boundary, the system can move more heat across that boundary than the power with which you drive it, (without breaking the laws of physics) Typically modern Heat pumps using modern refrigerants leverage the phase change energies of those refrigerants to obtain a CoP of around 3 to 1.
ie, 1kW of work can move 3kW of heat across the boundary. No heat is generated (other than that from the losses within the system) it is just moved from A to B. And because we are increasing the energy of the system, we can go AGAINST the temperature gradient.
For example, your kitchen freezer, gets it's insides down to aroud -15degC despite your kitchen being say 20 degC
You asked how can energy be extracted from ambient temp, and the answer is of course by cooling something down to less than ambient temp, at that point the heat flux is FROM the ambient media! So, if i want to take heat from a 10degC air outside, i just cool my evaporator down to 5degC and heat "magically" flows into my system!
Probably one of the most accurate and to the point posts you've made recently Max :-) Almost making me think I should apologise for going off one against your points, except I know how you've been with your other posts recently. A Heat pump doesn't "extract" thermal energy. It moves thermal energy. (which is why it's called a pump and not a "heater" or "cooler".
As you are just moving heat across a boundary, the system can move more heat across that boundary than the power with which you drive it, (without breaking the laws of physics) Typically modern Heat pumps using modern refrigerants leverage the phase change energies of those refrigerants to obtain a CoP of around 3 to 1.
ie, 1kW of work can move 3kW of heat across the boundary. No heat is generated (other than that from the losses within the system) it is just moved from A to B. And because we are increasing the energy of the system, we can go AGAINST the temperature gradient.
For example, your kitchen freezer, gets it's insides down to aroud -15degC despite your kitchen being say 20 degC
You asked how can energy be extracted from ambient temp, and the answer is of course by cooling something down to less than ambient temp, at that point the heat flux is FROM the ambient media! So, if i want to take heat from a 10degC air outside, i just cool my evaporator down to 5degC and heat "magically" flows into my system!
Yes the heat pump shifts the heat, but it is'n't very efficient at doing so, which is one of the main reasons heat pumps mostly make sense at static sites and where there are hot springs. And everything else I said on the points of heat pumps in EVs also remain true. I.e. If EVs use heat pumps to heat the cabin the heat pump will involve the AC componentry so EVs cannot have proper dehumidifying aircon and heat at the same time. This design is used on EVs to prevent faster battery drain and even worse range. This is a compromise in an area of comfort compared to any ice vehicle that features aircon.
Edited by SimonYorkshire on Monday 23 October 21:42
SimonYorkshire said:
Why don't you try fitting a heat pumps evaporator to a heat pump at 100 Kelivn and seeing if any hot air blows out of the condensor.
With the correct choice of refrigerant, in a multi-stage system, then yes, "hot air will blow out of the condensor"Nasa use heat pumps to cool sensitive detectors in scientific / observational space craft, which sit at just a few mDegC above abs. zero......
But what do NASA know compared to you eh Simon........
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