Go Back  PPRuNe Forums > PPRuNe Social > Jet Blast
Reload this Page >

Recirculated cabin air: Uber version

Jet Blast Topics that don't fit the other forums. Rules of Engagement apply.

Recirculated cabin air: Uber version

Old 10th Sep 2018, 19:12
  #1 (permalink)  
Thread Starter
 
Join Date: Mar 2014
Location: LAX
Posts: 20
Recirculated cabin air: Uber version

Last 25 Uber trips, roughly 90% of my drivers had the “recirculate” button on throughout entire trip. AC on, windows up, recirc selected. Not healthy, I would think. Especially for driver recirculating air all day; as for me, I just crack a window.
Thoughts? And does anyone know exactly how much fresh air is brought into an auto cabin, windows up, when recirc is selected?

Last edited by 5000 metres; 10th Sep 2018 at 23:26.
5000 metres is offline  
Old 10th Sep 2018, 20:06
  #2 (permalink)  
 
Join Date: Dec 2005
Location: Wellington,NZ
Age: 61
Posts: 1,630
In my experience, having sometimes inadvertently left the recirc control on after going through a tunnel, very bloody little, if any.

It's not only Uber. Most taxi drivers seem to do this.
Tarq57 is offline  
Old 10th Sep 2018, 20:40
  #3 (permalink)  
 
Join Date: Jan 2017
Location: europe
Posts: 8
You might want to talk to them

arketip is offline  
Old 10th Sep 2018, 22:54
  #4 (permalink)  
 
Join Date: Dec 2010
Location: Balikpapan, INDONESIA
Age: 67
Posts: 491
Interesting. I'd like to hear an informed explanation of how RECIRC works.
I have always assumed that RECIRC still allows in some percentage of fresh air.
I always drive with RECIRC set and know that I can do so for 2 - 3 hours without noticing any problems.
5 - 600 km has never presented any major problems, even if it's not recommended.

30 minutes of oxygen in a large sedan, presumably with just the driver onboard, is clearly not the case.

There may be a case for not using RECIRC, but I'd like to hear a balanced opinion first.
WingNut60 is online now  
Old 10th Sep 2018, 23:26
  #5 (permalink)  
 
Join Date: Jun 2017
Location: A land down under
Posts: 24
WingNut60, I agree with you. I spent >40 years living in Darwin where it is hot and humid most of the year. RECIRC means that the aircon isn't having to cool the air continuously, and aids the performance of the aircon greatly.

I have also driven around Australia , or "south" and back, many times. 1000 - 1200 km per day is the norm, although of course there are stops every couple of hours to stretch the legs - presumably all cabin air is changed over at that time? Oh, and that's with passengers and sometimes also a couple of small dogs. If no fresh air was being introduced, I'm sure I would be dead well before now.

I do recall a hire car in England a few years back where back seat passengers would doze off, but we attributed that to leakage of exhaust gasses as front seat passengers (and driver) were unaffected. That was a dreadful Vauxhall people mover of some description.
Recidivist is offline  
Old 11th Sep 2018, 07:08
  #6 (permalink)  
 
Join Date: Oct 2002
Location: West Wiltshire, UK
Age: 66
Posts: 369
Pretty much every car I've owned has had air extract ducts hidden down the back somewhere, often with rubber flaps over them and often hidden under the rear trim. These are located in a low pressure area when the car is in motion, so there is slight suction on them, to draw stale air out of the car. I doubt that any car is very airtight, so even with the recirculate option selected some fresh air seems likely to be drawn into the cabin.

As stated above, the recirc option is really useful for improving the air con efficiency (it helps cool my car more quickly if I get into it when it's been parked during a hot day), demisting the inside of the car quickly in coo, damp weather, etc, and it seems crazy to start some half-baked campaign to ban it. Like others, I expect, I tend to hit the recirc button when driving through tunnels, and when there's smoke around from bonfires etc, just to keep the cabin air a bit cleaner. I'd guess that using the control sensibly may give greater health benefits than banning the thing.
VP959 is online now  
Old 11th Sep 2018, 08:20
  #7 (permalink)  
Just an other digit
 
Join Date: Aug 2001
Location: a million miles away
Posts: 90

Well that looks legit too.

Last edited by Just an other number; 11th Sep 2018 at 08:22. Reason: Well that looks legit
Just an other number is offline  
Old 11th Sep 2018, 08:45
  #8 (permalink)  
 
Join Date: Apr 2004
Location: Richard Burtonville, South Wales.
Posts: 1,791
Originally Posted by Recidivist View Post
I have also driven around Australia , or "south" and back, many times. 1000 - 1200 km per day is the norm, although of course there are stops every couple of hours to stretch the legs - presumably all cabin air is changed over at that time? Oh, and that's with passengers and sometimes also a couple of small dogs. If no fresh air was being introduced, I'm sure I would be dead well before now.
Obvs for no longer than 45 mins at a stretch though, or your oxygen would have run out!

CG
charliegolf is offline  
Old 11th Sep 2018, 08:52
  #9 (permalink)  
 
Join Date: Dec 2010
Location: Balikpapan, INDONESIA
Age: 67
Posts: 491
A clear warning sign would be if your cigarettes started to self-extinguish.
WingNut60 is online now  
Old 11th Sep 2018, 09:06
  #10 (permalink)  
 
Join Date: May 2002
Location: U.K.
Age: 42
Posts: 158
Moms Against Cars

A quick google has taught me that ‘Moms Against Cars’ is in fact a pro-gun facebook group, attempting to highlight the ‘stupidity’ of the ‘Moms Against Guns’ and other simular groups
Jump Complete is offline  
Old 11th Sep 2018, 09:26
  #11 (permalink)  
 
Join Date: Nov 2015
Location: Farnham, Surrey
Posts: 1,190
It's twaddle. In every car I've looked at in detail the "recirc" control just changes the input to the heater/aircon system from the external intake (via pollen filters) to an internal intake, so it pushes cabin air through the heater/aircon making for faster warm-up or chill-down.

But the heater/aircon intakes are not the only air inlets, there are plenty of others (both designed inlets and leaks around things that go through the cabin - car cabins are not hermetically sealed) so I seriously doubt you'd ever suff4er oxygen depletion. But having said that - I only use recirc to warm-up or chill-down and once it's achieved a comfortable temperature I switch back to external intake for fresher air. I suspect taxi drivers leave it in recirc because they spend significant time with the engine off, and so often don't get to the steady-state temperature.

Having said that, I personally don't use taxi drivers as my role-model gurus on sucg matters anyway...

PDR
PDR1 is offline  
Old 11th Sep 2018, 09:39
  #12 (permalink)  
 
Join Date: Jul 2002
Location: The bar of the Frog and Peach
Posts: 73
My car's manual warns against using recirc to improve warm up when trying to de mist the screens. The incoming air is dehumified so recirculating it just recirculates moist air defeating the object.
Carry0nLuggage is offline  
Old 11th Sep 2018, 15:52
  #13 (permalink)  
 
Join Date: Oct 2002
Location: West Wiltshire, UK
Age: 66
Posts: 369
Originally Posted by Carry0nLuggage View Post
My car's manual warns against using recirc to improve warm up when trying to de mist the screens. The incoming air is dehumified so recirculating it just recirculates moist air defeating the object.
If the aircon is on then the cabin air will be dehumidified more every time it gets recirculated through the cold heat exchanger inside the cabin air system, as the heat exchanger will usually be well below the dew point of the air in the cabin.

I know for sure that if I press the screen demist button the car ventilation system does four things; it turns the fan speed up, it switches the aircon on, it switches from external air mode to recirculation mode and it re-directs the air flow to the windscreen and side window demist outlets. The air coming out of those outlets will be drier than the cabin air because it will have passed through the cold heat exchanger, which makes it more effective at evaporating the mist off the inside of the windows. You can see it doing this on the controls, as the symbols change in the display and both the aircon and recirc lights come on.
VP959 is online now  
Old 11th Sep 2018, 16:53
  #14 (permalink)  
 
Join Date: Jul 2002
Location: The bar of the Frog and Peach
Posts: 73
VP959: Different cars - Different systems. Checking mine, it repeats this message 6 times on the climate control page! Extraordinary. The demister function disables recirc though it does speed up chilling down. The cabin starts to feel very muggy though when you do that.

Going back the OP, mini cab drivers are not noted for their car sympathy and I don't expect Uber drivers to be different.
Carry0nLuggage is offline  
Old 11th Sep 2018, 17:16
  #15 (permalink)  
 
Join Date: Nov 2004
Location: UK
Posts: 438
Originally Posted by VP959 View Post
Pretty much every car I've owned has had air extract ducts hidden down the back somewhere, often with rubber flaps over them and often hidden under the rear trim. These are located in a low pressure area when the car is in motion....
Where do they move to when the car stops?
pilotmike is offline  
Old 11th Sep 2018, 17:24
  #16 (permalink)  
 
Join Date: Nov 2015
Location: Farnham, Surrey
Posts: 1,190
Milton Keynes.

PDR
PDR1 is offline  
Old 11th Sep 2018, 17:50
  #17 (permalink)  
 
Join Date: Oct 2002
Location: West Wiltshire, UK
Age: 66
Posts: 369
Originally Posted by pilotmike View Post
Where do they move to when the car stops?
They don't, but then they are in a static pressure region so there's not likely to be any flow through them...
VP959 is online now  
Old 11th Sep 2018, 22:42
  #18 (permalink)  
Psychophysiological entity
 
Join Date: Jun 2001
Location: Tweet Rob_Benham Famous author. Well, slightly famous.
Age: 79
Posts: 4,669
car cabins are not hermetically sealed
Tell that to the owner of a new TVR that was offering a few rides to guests in my house. He did the first run and then took the second lot out. They came back in moments later. "we'll have to wait for a few minutes'.

It seems that if you were frantic to get going, you could remove the rear numberplate and poke something in a hole.

"A big mistake".

I'll say. £47,000 in, and 21k out less than a year later.
Loose rivets is offline  
Old 12th Sep 2018, 03:00
  #19 (permalink)  
 
Join Date: Mar 2002
Location: Florida
Posts: 5,079
Originally Posted by WingNut60 View Post
A clear warning sign would be if your cigarettes started to self-extinguish.
Who goes first, the cigarette or the guy ........ i'm betting the guy smoking it. Anybody tried this in an altitude pressure chamber? or while flying unpressurised?
lomapaseo is offline  
Old 12th Sep 2018, 06:20
  #20 (permalink)  
 
Join Date: Jul 2002
Location: The bar of the Frog and Peach
Posts: 73
Originally Posted by lomapaseo View Post
Who goes first, the cigarette or the guy ........ i'm betting the guy smoking it. Anybody tried this in an altitude pressure chamber? or while flying unpressurised?
Isn't part of the fire risk of cigarettes that cigarette tobacco has it's own oxidiser?
Carry0nLuggage is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.