Tesla AC -> cool?

SwampNut

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My friend in WA is reporting that people are having medical emergencies for the 80 degree weather. Here it's trivial. Is it tolerance? Is it the way heat behaves in the desert versus a humid environment? I'm not sure. I don't think we will get down to 80 for a month or two, and everyone I know is happy being outside in the evening. It's weird, and different.

I have relatives visiting from Miami tomorrow, they think they are going to die because they are thinking it will be humid *and* 105. Meanwhile, I can't stand being outside there and constantly soggy.

 

Ogre

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When the humidity is insanely low, even mountain biking in the desert feels decent at 80. Also, the high temp for the day only happens for a short window. It's very different from how you would perceive it not living here. Like I go to visit relatives in FL, and I'm dying from humidity at only 75. It's also 75 all damn day.
I don’t have to imagine it. I’ve been there. I also lived in California for decades with similar “Dry Heat”. Done big rides in Vegas and Reno. “Enjoyed” evening walks in Phoenix. I’ll pass.

I do agree about humidity. I stayed with family in Kansas and it was immeasurably worse. I cannot imagine how someone can live anywhere with months of 90+ weather and 90% humidity.

But just because something is worse doesn’t make it less bad.
 

John K

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Hot environments… cold environments… I’ve read about those concepts living in the marine layer area in Los Angeles. 😈👍
 

Crissa

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Yes, 86F 100% humidity is where the human body can no longer cool itself, and even athletes would die.

So of course you will have some portion of people have medical emergencies at 80F.

Also, home design is such that it depends upon power and the right weather. If the house cannot cool itself off, you will have temperatures and humidities exceeding the outside weather, too.

In the high desert, you can get chilled water just by letting some of it evaporate. I loved that. Crack you water bottle, put it between a couple rocks, and sure, it's 80F and you've been climbing around in the sun, but that water is now 50F easily.

Can't do that in Florida, as you pointed out.

-Crissa
 

SwampNut

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It's 86 here now and around 50% humidity. I walked out to get something from the car and thought I was going to die.

I'm guessing most people here would wonder what a swamp cooler is, and think we're nuts that we run a house humidifier all year.
 


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Even with the octovalve setup if the COP goes under 1 because of low external temperature the motor electrical coils are used to heat the cooling circuit. Like a resistive circuit, by intentionally pulsing current in an inefficient manner through the coils to create the necessary heat to warm the vehicle.

As for your F150, a peice of cardboard or plastic sheet in front of the radiator would have helped.

Really, Tesla should offer a cold package for colder climates that includes a passenger and battery insulation package. You only need to consume energy to create enough heat to replace what you lose to the environment, so reducing thermal losses means greater range. Good thing about insulation is it is very light weight and cheap, and reduces road noise etc as well.
It may just be my inner voice translating your words, but it borders on pedantic to claim the motor as a resistance heater and to offer me advice about my truck. I was using the truck as a comparative example of how cold it gets where I live and how capable the Model 3 is regarding climate control. All things considered, I agree that Tesla's engineering teams are amazingly resourceful and creative. Further, the coefficient of performance is a measure of efficiency and the way I choose to understand it is like how gear reduction amplifies input. Given the temperature range of R134 and the efficiency of electric motors, the temperature of the air outside a model 3 with a heat pump (including wind chill effect) would have to be damn near -100F to decompensate the heat pump. My math is not perfect because it would take too much time to do more than estimate for such a wild worse case scenario.
I support your suggestion of a winter package for northern climes. But, my standard range model 3 is exceptionally competent making the journey, comfortably, across the Blue mountains in winter in its current configuration. The only change I made is studless winter tires. The range difference, even in the worst winter weather, is insignificant because the charging network is well within range and I have to stop at each charger currently in the most favorable conditions.

The takeaway here is that Tesla cars are not just efficient they are capable in the all conditions except deep, newly fallen, snow. This is the only situation I have found in my winter wonderland home that has stopped my car. High centering the flat bottom of my Tesla on fluffy snow while the traction control keeps the wheels from spinning wildly like a fat bellied dog on a hard wood floor.
 

Challeco

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There's a temp setting for each side. Literally exactly what you are looking for. It's right on the screen unless someone changed it to remove it (and I don't even think you can).
There is also a seat heater... which the user manual indicates is the most efficient way to heat the passengers in a low power/range challenging event.
 

Challeco

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Ah, I remember them good ol' days where R12 reigned supreme but was bad for the ozone layer. The ability to take bigger bites of heat each cycle were so good though! R134a is still good but just can't take as much energy so it takes more cycles. I love the upgrade of the octovalve from the traditional heat pump design. I will say that the Tesla app doesn't allow me to set the temp below 59F/15.5C without just going to "LO". So, I cannot reliably store refrigerated goods. But, less than 60F from 140F (cabin overheat protection) is still amazing.
I tested the app just now. It took less than 5 minutes to drop from 33C to 19C before I turned off the active cooling. So, I would call this a good system.
I was showing a coworker how I could control my car through my app yesterday. I showed him the climate controls and set it to low this time. I accidentally left it running. The app notified me that the climate control had been on an extended amount of time, so I turned it off. Then I noticed that the temperature in the car was a nice refrigerated 11C while it was 36C outside. Mischief managed. Tesla's octovalve is better than R12 from the early days of air conditioning. I would bet that I could set the car to keep my groceries refrigerated.
 

JBee

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It may just be my inner voice translating your words, but it borders on pedantic to claim the motor as a resistance heater and to offer me advice about my truck.
Yep I think it is. I'm in the business of sharing information on this forum. If it wants to be heard or even sometimes not. 🙂

My point was different vehicles, with different propulsion types, have different solutions.

An ICE is primarily a heat generator that requires protection from heat loss in cold climates as it is optimised to operate (read cool) in the warm, whereas a EV primarily uses its stored energy for forward motion, making it more susceptible to cold temperatures for cabin heat and subsequent range loss.

Further, like the "winter package" option for Tesla, the solution to heat loss and heat gain is to generally limit heat flow.

Be that through a peice of cardboard in front of your F150 radiator or by installing a HRV setup on a Tesla to reuse outflowing heat in the air at 95% efficiency when the blower air input is set to fresh. The HRV will work both summer and winter and is nothing more than a air to air heat exchanger that would cost around $100-150.

To insulate a 1/2" layer aerogel pad stuck on the inside of the door module would already help, seeing door skin will the primary areas for heat conduction, along with a pullout blind on each window that isn't already double glazed.

As for your driving example, there are other metrics that need to be known for an accurate representation of vehicle performance. For one your mile/kwh with and without the heat on for the same stretch of road and speed, the ambient conditions including precipitation (wet roads increase consumption up to 20% because of the amount of water lifted by the tyres), altitude differences, vehicle load (people and luggage) etc.

As you can see a statement like "I drove a non-descript jouney and felt warm all the way" doesn't cut it as a valid comparison in my book. But maybe that is just me? 😋
 

JBee

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What you really need to look at to compare climates is the the dew point temperature, which combines both temperature and humidity into a single metric. This is also sometimes known as the "feels like temperature", as the body losses it's ability to cool itself at high humidity levels, because the skin can't evaporate moisture for cooling in air that is already saturated.

That's also why evaporative coolers only work in dry climates properly, because most of the heat energy carried in the air is in the water vapor, nitrogen and oxygen have a very low thermal mass in comparison and doesn't carry much heat. Many commercial air conditioning units therefore utilize a dehumidifier to reduce the water content of warm air, before they cool it with the heat pump, to save energy.
 


happy intruder

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I am from Atlanta originally......came to So Cal in 1973 when I was stationed at El Toro......great weather.....no humidity!....when I went back to visit my parents, when I was outside I thought I was going to drown......but after 12 years in So Cal I was transferred to New Orleans....we ran 5 miles a day......88F-95F and 95% humidity.....Horrible......It took me over an hour to cool off after a shower with cold water.....i hated that place for 6 years......back to So Cal and had to move company from Phoenix is August....it was in the 1991 time frame when there was temperature records daily.....at 11:30pm, outside temp was 106F!....could not go outside.....my wife came over to surprise me and left 2 days later......but I still like SoCal, even when it gets hot (95F)....

My motorcycle buddies and I go to Borrego Springs in Oct, Jan and April to camp.....temps there range from 38F to 100F....not bad but it is dry.....have to drink lots of water
 

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Yep I think it is. I'm in the business of sharing information on this forum. If it wants to be heard or even sometimes not. 🙂

My point was different vehicles, with different propulsion types, have different solutions.

An ICE is primarily a heat generator that requires protection from heat loss in cold climates as it is optimised to operate (read cool) in the warm, whereas a EV primarily uses its stored energy for forward motion, making it more susceptible to cold temperatures for cabin heat and subsequent range loss.

Further, like the "winter package" option for Tesla, the solution to heat loss and heat gain is to generally limit heat flow.

Be that through a peice of cardboard in front of your F150 radiator or by installing a HRV setup on a Tesla to reuse outflowing heat in the air at 95% efficiency when the blower air input is set to fresh. The HRV will work both summer and winter and is nothing more than a air to air heat exchanger that would cost around $100-150.

To insulate a 1/2" layer aerogel pad stuck on the inside of the door module would already help, seeing door skin will the primary areas for heat conduction, along with a pullout blind on each window that isn't already double glazed.

As for your driving example, there are other metrics that need to be known for an accurate representation of vehicle performance. For one your mile/kwh with and without the heat on for the same stretch of road and speed, the ambient conditions including precipitation (wet roads increase consumption up to 20% because of the amount of water lifted by the tyres), altitude differences, vehicle load (people and luggage) etc.

As you can see a statement like "I drove a non-descript jouney and felt warm all the way" doesn't cut it as a valid comparison in my book. But maybe that is just me? 😋
Your point is dazzle with B.S.. your claim about CoP is moot when the actual range of comfortable heat exchange with R134 is capable of compensating for dangerous environmental conditions. To remind you the CoP of one is equivalent to 1000W of input to 1000W of heat output. Traditional heat pumps have CoP of >2 with the Octovalve being >4. To honor the original question of this string, my anecdotal evidence that the climate control is as good as an I.C.E. car trumps your hypothetical extremes. Oh, and it is an F250.
 

JBee

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Your point is dazzle with B.S.. your claim about CoP is moot when the actual range of comfortable heat exchange with R134 is capable of compensating for dangerous environmental conditions. To remind you the CoP of one is equivalent to 1000W of input to 1000W of heat output. Traditional heat pumps have CoP of >2 with the Octovalve being >4. To honor the original question of this string, my anecdotal evidence that the climate control is as good as an I.C.E. car trumps your hypothetical extremes. Oh, and it is an F250.
Hey buddy. COP is not linear, it decreases with increased temperature difference.

So at 10degrees differences the COP is higher (4-5) than at when the difference is 30 degrees or more and COP is lower. That is why I kept on saying it uses alternative heat sources, like motor windings, lossy switching etc when COP of the heat pump is under 1, where it becomes more efficient to use energy 1:1 with resistive type heating. Re-read my posts to see that my arguments were always defined that way.

This is also why I questioned what the environmental conditions of the drive are because it plays a large roll in determining what system is used for what and how that changes the COP..

To be clear what actually are you trying to prove, that a Tesla electric heat pump works better than sourcing heat from a ICE cooling jacket? Because I never argued that. Or is it that resistive heating heating is not used in Teslas? How old is your M3 because the first ones did and any of the newer octovalve ones do if the heat pump COP is less than 1 because the delta-T is too high.
 
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ED_SFO

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My MYP A/C is really good! Seems to get cold slightly faster than my ICE vehicle, but what's great is that u can turn on the a/c before u get to your car and it's one of the best features I think tbh. Not sure why ppl are spending so much on tint when remote a/c is great. I just tinted my two front windows for looks and have a two piece roof shade to stop radiant heat. I never look up from the driver's seat tbh...I usually leave the back one off for passengers but I also rarely drive ppl back there anyways.
 

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Hey buddy. COP is not linear, it decreases with increased temperature difference.

So at 10degrees differences the COP is higher (4-5) than at when the difference is 30 degrees or more and COP is lower. That is why I kept on saying it uses alternative heat sources, like motor windings, lossy switching etc when COP of the heat pump is under 1, where it becomes more efficient to use energy 1:1 with resistive type heating. Re-read my posts to see that my arguments were always defined that way.

This is also why I questioned what the environmental conditions of the drive are because it plays a large roll in determining what system is used for what and how that changes the COP..

To be clear what actually are you trying to prove, that a Tesla electric heat pump works better than sourcing heat from a ICE cooling jacket? Because I never argued that. Or is it that resistive heating heating is not used in Teslas? How old is your M3 because the first ones did and any of the newer octovalve ones do if the heat pump COP is less than 1 because the delta-T is too high.
Okay, I am not trying to prove anything. The original poster asked if Tesla's climate control is equal to or better than an internal combustion engine's air conditioning system. I responded with my anecdotal evidence and experiences. You came up with a whole bunch of technical jargon to dismiss my observations. I used an example of my experience with my truck to provide background of how cold it gets where I live and travel. You decided to mansplain my truck experience while missing the point that it was a comparative. You also mansplained that a heat pump has limitations, disregarding the original questions intent. That intent was "is the climate control capable?". Without any big words, I explained that my Model 3 cools my car in very hot conditions and warms my car in very cold conditions.

You decided to try to prove yourself "right" and continue to try and validate your point. Which is what? Are you saying that the Tesla system which controls the environment of the batteries, the motors, AND the cabin is flawed??!! Because what I read from your arguments is that Tesla wisely, elegantly, and cleverly conditions the motors, the batteries, and the passenger areas selectively to each need without the use of heavy and bulky extra equipment. Which is, by definition, agreeing with the points that I made.

This leads me to believe that we agree, but based on a misunderstanding/misreading of the original postings you have to educate me on how I am somehow wrong for agreeing with you?

 

 
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