GWR Class 165/166 air conditioning / use of hopper windows

[Bletchleyite]

My car is noticeably slower when the aircon is on. Fine when cruising, but when I want to accelerate quickly onto Motorways, I turn it off for 5 seconds

I find with mine that if I'm in too high a gear, if you get to a slight hill the turbo has spun down and you lose power. The aircon kicking in can do the same thing. Some will probably automatically adjust the engine speed to compensate so it may not be as noticeable.

 

[DelW]

EVs and PHEVs have to have electric heating and a/c, as they need to be usable without an engine running.
It also means you can use the HVAC system to get the car to your required temperature before setting off, running off the mains supply if plugged in (or the battery if not).

 

[Bletchleyite]

EVs and PHEVs have to have electric heating and a/c, as they need to be usable without an engine running.
It also means you can use the HVAC system to get the car to your required temperature before setting off, running off the mains supply if plugged in (or the battery if not).

And back round to trains...this sort of feature would be really quite useful via a shore supply (or OHLE) for trains sat on depot, so they aren't going out roasting hot/freezing cold and taking ages to warm up/cool down.

 

[Stigy]

My car is noticeably slower when the aircon is on. Fine when cruising, but when I want to accelerate quickly onto Motorways, I turn it off for 5 seconds

I only ever found that on a hire car I once had. An 800cc Daewoo Matiz…

 

[Domh245]

Generally cars with engine driven compressors do have an automatic clutch type arrangement (typically magnetic or solenoid driven, from a quick Google) to disconnect the compressor pump from the engine when you turn the aircon on and off (or if the refrigerant pressure drops too much). You can hear the engine working harder or less hard as you flip it on and off while idling - this wouldn't be the case if it was connected permanently.

They do, but I was thinking more that if you wanted to run the compressor at part speed, you either go electric compressor with variable speed drive on the motor, or you have to have try and control the clutch pressure, and thus slip, to change the compressor speed (at no real energy saving + requiring AC compressor clutch plates to be changed frequently!). Evidently running the compressor constantly isn't an issue (thinking overcooling the air) as they'll just bypass the evaporator if necessary, but would be nice to see some of the inverter technology that's been common in most other refrigeration systems since the 80s) make it's way to cars!

EVs and PHEVs have to have electric heating and a/c, as they need to be usable without an engine running.

The particularly disheartening thing is that most EVs seem to use resistive heating for primary heat, with it's measly 100% efficiency, when they could use the AC system as a reversible heat pump and make use of the >100% efficiency of refrigerant based systems!

And back round to trains

Oh yes, that was the topic originally wasn't it?

 

[Stigy]

And back round to trains...this sort of feature would be really quite useful via a shore supply (or OHLE) for trains sat on depot, so they aren't going out roasting hot/freezing cold and taking ages to warm up/cool down.

I was surprised at just how quickly a 165 cooled down with decent A/C from starting it up on depot a couple of weeks ago. 10 minutes and it was like a fridge in there. It seems to be one extreme to the other, but generally 2 car 165s seem to be better and more consistent both with in-cab cooling and passenger area cooling.

 

[gallafent]

The issue would be helped if the system had road-coach-style (or aircraft-style) personal vents to provide moving air for individuals. I think one of the Networker classes does?

Class 365 I think. Which also (I think) don't have air conditioning, and every window has a hopper. Might be misremembering any-to-all of that though.

I'm curious to hear what car this is!

Assuming you mean mine, it's just a 2007 Prius (gen 2) … it's fact 13 on this page. Toyota were way, way ahead, on many things, with the Prius, back then.

13) Toyota designed a new world-first electric air conditioning system for the second-generation Prius that deleted its dependency – and therefore its fuel draw – on the petrol engine. Powered now by the hybrid battery, it also meant the interior could continue to be cooled when the engine was shut off.

I recently read an interesting article about where they are at the moment, which paints a very different picture.

Yet, Toyota hadn't picked up on the subtle shift that was occurring. It's true that hybrids were a bridge to cleaner fuels, but Toyota was overestimating the length of that bridge. Just as Blackberry dismissed the iPhone, Toyota dismissed Tesla and EVs. Blackberry thought the world would need physical keyboards for many more years. Toyota thought the world would need gasoline for several more decades. Both were wrong.

 

[O L Leigh]

Class 365 I think. Which also (I think) don't have air conditioning, and every window has a hopper. Might be misremembering any-to-all of that though.

Pressure ventilation only. In other words, ambient air not A/C.

 

[gallafent]

On the general subject of users and thermostats, many years ago I came to the conclusion that the majority of the population just don’t understand how a thermostat works. Whether for heating, cooling or both.

You often find the thermostat turned to maximum. And if you ask the user why, they tell you that turning up (or down) the thermostat produces more heat/cold. WRONG! But some people will still argue the point.

Agreed, it's a bit depressing.

Having said that, there is a grain of truth in your second paragraph, when we're talking about the mechanical wax diaphragm type thermostats (e.g. standard non-“smart” radiator thermostats), which have a noticeable range of temperatures between “fully on” and “fully off”, so if the air temperature is approaching the set point, the flow is reduced, … to the extent that the radiator can become warm to the touch rather than hot. Of course, this is in fact exactly the behaviour you want in a system with that much thermal mass, to avoid overshoot / oscilation, etc., but convincing people of that is even harder … if it's not warm enough in the room and the radiator isn't hot enough to burn your hand (so it's close to its set point), then maybe nudge the stat up by a quarter of a whole-number division (yes, I wish they would write the actual temperatures on them too), … but no, because you want it to be exactly the right temperature NOW you will turn it up to MAX. Which steals flow from other radiators, of course, leads to higher return temperatures to the boiler, more cycling, less condensing, and in 20 minutes from now it will be much too hot in the room (so they will turn it down to 1 or *), blah, blah, blah, … head hits desk.

Giving control to users? Never a good idea, amirite

The particularly disheartening thing is that most EVs seem to use resistive heating for primary heat, with it's measly 100% efficiency, when they could use the AC system as a reversible heat pump and make use of the >100% efficiency of refrigerant based systems!

That is indeed disheartening. Fingers crossed that as competition increases, the use of the “you've got it anyway” AC's heat pump “in reverse” to heat the cabin becomes more commonplace. I mean, you could even use the resulting coolth on the other side of it as an aid to battery and drivetrain thermal management too, if you were thinking holistically ………

 

[FenMan]

Reading this thread has been like being aboard a wonky shopping trolley steered by a drunk. But I'd like to think we've established GWR's 165 retrofit works well, except when passengers do stupid things.

So perhaps the thread title should be corrected to "GWR Class 166 air conditioning / use of hopper windows"?

 

[Stigy]

Reading this thread has been like being aboard a wonky shopping trolley steered by a drunk. But I'd like to think we've established GWR's 165 retrofit works well, except when passengers do stupid things.

So perhaps the thread title should be corrected to "GWR Class 166 air conditioning / use of hopper windows"?

It’s hit and miss. A lot of units simply have ineffective A/C. Some have working saloon A/C but ineffective cab A/C, some have effective cab A/C but ineffective saloon A/C. If it’s not working after 40 or 50 minutes from startup, or if I join the train halfway through its journey or something and it’s like an oven, I open windows.

 

[gallafent]

But I'd like to think we've established GWR's 165 retrofit works well, except when passengers do stupid things.

… so this thread includes discussion of the GWR 165 retrofit air-cooling … and that passengers do things such as opening hopper windows in situations that mean that it will have the opposite effect to that which they desire …

So perhaps the thread title should be corrected to "GWR Class 166 air conditioning / use of hopper windows"?

… and so what is the logic in removing 165 from the thread title? As you say yourself above, in this thread the system in the 165 has been discussed!

 

[FenMan]

… so this thread includes discussion of the GWR 165 retrofit air-cooling … and that passengers do things such as opening hopper windows in situations that mean that it will have the opposite effect to that which they desire …

… and so what is the logic in removing 165 from the thread title? As you say yourself above, in this thread the system in the 165 has been discussed!

I'm still waiting for someone to provide firm evidence that retrofitting the 165s hasn't worked (excepting when passengers/staff intervene to open the windows, which won't have been designed into the system).

As a North Downs Line user I know it works.

The 166s on the other hand .... some were awful, but they don't run on the North Downs Line anymore.

 

[Bletchleyite]

I'm still waiting for someone to provide firm evidence that retrofitting the 165s hasn't worked (excepting when passengers/staff intervene to open the windows, which won't have been designed into the system).

As a North Downs Line user I know it works.

The 166s on the other hand .... some were awful, but they don't run on the North Downs Line anymore.

I don't think anyone is saying it didn't?

 

[northernbelle]

I don't think anyone is saying it didn't?

A couple were, but they're just the usual 'moan about everything' brigade!

 

[fgwrich]

A couple were, but they're just the usual 'moan about everything' brigade!

Of course! I mean, why should I moan about something that erm, didnt work and resulted in having to open the windows, thus defeating the point of Air Cooling!

I forget, it’s the never does anything wrong and always faultless GWR.

Perhaps if they were maintained as per the higher standards of the Chiltern fleet, they wouldn’t require the openable windows as back up. But that would require First Group to, actually maintain their fleet properly as opposed to using “Sorry, Under Maintenance” stickers, the longest of which I saw last week publicly said “Awaiting Parts - 08/20”.

 

[northernbelle]

Of course! I mean, why should I moan about something that erm, didnt work and resulted in having to open the windows, thus defeating the point of Air Cooling!

I forget, it’s the never does anything wrong and always faultless GWR.

Perhaps if they were maintained as per the higher standards of the Chiltern fleet, they wouldn’t require the openable windows as back up. But that would require First Group to, actually maintain their fleet properly as opposed to using “Sorry, Under Maintenance” stickers, the longest of which I saw last week publicly said “Awaiting Parts - 08/20”.

We're talking specifically about air cooling fitted to class 165s, my point being that it's generally very reliable if not 100% perfect.

Nobody here is denying that, in general, the fleet needs some TLC.

 

[Pigeon]

But by opening the vents all you are ensuring is that the system will fail to cope.

No, what he is saying is that the system already fails to cope, and therefore it is necessary to open the vents.

If the system then responds by reversing its behaviour entirely and heating instead of cooling, then it is badly designed. As you have in fact described:

Well, the coach thermostats reside inside the ceiling panels along with the rest of the A/C gubbins... The air blast that enters the coach does so at ceiling height, travelling along the ceiling panels and hitting the coach thermostat. This tricks the thermostat into thinking that the coach is too cold and the A/C switches from cooling to heating.

There are two points here. Point one is that the thermostat is wrongly positioned. It should be located so that it detects a temperature which is representative of the carriage as a whole. Since it evidently does not do this, the design is bad. The thermostat does not have to be adjacent to the rest of the gubbins; it can be anywhere you can run a wire to, but someone would have had to think about that and they couldn't be bothered.

Point two is that the hopper vents are also badly designed, because they do not direct the airflow to where it is needed, but send what flow they do manage to admit in a direction that does no good (aircon or not). As of course we all know if we have ever tried to achieve decent ventilation using them...

The system is not "working perfectly"; it is failing at multiple points.

Johnny Q Public comes along and opens a vent for no good reason other than it's a nice sunny day outside.

There are other reasons for opening vents than simply trying to adjust the temperature. It's nice to have a bit of fresh air when the weather allows instead of stuffy stagnant muck. Also, there is a roughly even chance that someone in the carriage will be drenched in some chemical warfare agent; it only takes one, and the choice is to open a window or feel ill all the rest of the day. The loss of decent openable windows is a significant factor in why train travel these days is much less pleasant than it used to be.

Unfortunately with some types of air conditioning systems, they ice up and then fail to work properly if they run continuously.

Yes. Crap ones. It happens because the evaporator matrix is too small and/or the airflow through it too little to achieve the necessary rate of heat transfer without an excessive temperature differential between the air and the metal. Another consequence is reduced efficiency and higher energy consumption in normal operation.

Playing games with the thermostat is not the right way to deal with this; it just makes an already ineffective system even less effective. A decentish bodge solution is to fit an air flow meter which detects the reduction in airflow from incipient icing before it develops into a total blockage, and shuts the compressor down, leaving the fan running, until the airflow returns to normal, but the correct solution is to have installed a properly designed system with correctly sized components in the first place.

Add in the greenhouse effect of the sun through the windows...

Oh yes, nothing like a bit of directional radiant spot heat to mess up an averaging system. Perishing cold icy winter's day, train heating quite reasonably running full pelt... but it's a sunny winter's day, with that blasting low winter sun shining full in through the windows and directly onto me, giving me a few hundred watts of purely personal thermal input, and I melt.

 

[FenMan]

Of course! I mean, why should I moan about something that erm, didnt work and resulted in having to open the windows, thus defeating the point of Air Cooling!

I forget, it’s the never does anything wrong and always faultless GWR.

Perhaps if they were maintained as per the higher standards of the Chiltern fleet, they wouldn’t require the openable windows as back up. But that would require First Group to, actually maintain their fleet properly as opposed to using “Sorry, Under Maintenance” stickers, the longest of which I saw last week publicly said “Awaiting Parts - 08/20”.

So you've had a bad experience on a retrofitted 165.

Please do share where you travelled from and to.

 

[fgwrich]

So you've had a bad experience on a retrofitted 165.

Please do share where you travelled from and to.

In response to your amazingly sarky tone, I used a number of 165/166 combinations last week between Portsmouth Harbour and Southampton Central. Unfortunately I cannot tell you the exact seat number because of the silly seat number positioning on the handrail adjoining the luggage racks. Until fairly recently, I also commuted on them between Basingstoke and Reading for the last 4 years, so have used from before the Air Cooling was fitted to the last few months. And yes, it is infallible. As others have mentioned as well as myself, particularly if and where there is a fault that can only be identified during the day, but is only attended to during the cooler nights. As I said before, if GWRs maintenance regime was up to the same standard as Chilterns, and if they had the full confidence in their system as Chilterns, then perhaps they should have removed the hopper windows as well.

Unsurprisingly the 166s were the worst offender, with nearly all virtually offering next to nothing on the Air Con or working PA front, but, as the point of this thread is, a small number of 165s without a working Air Cooling as well.

 

[northernbelle]

And yes, it is infallible.

I think you need to check what that word means - it suggests it's perfect....

and if they had the full confidence in their system as Chilterns, then perhaps they should have removed the hopper windows as well.

The hoppers were kept not because the air cooling system wasn't trusted but as a matter of cost management. There is an argument that keeping them as back up doesn't do any harm, but that does rely on them being locked when not required.

Of course Chiltern doesn't have to battle with the 166 air con system so it's hard to make a comparison on the maintenance regimes of it. I travel on dozens of Turbos a year and I'm yet to experience one with failed air cooling - not that I'm saying anything is perfect.

 

[O L Leigh]

No, what he is saying is that the system already fails to cope, and therefore it is necessary to open the vents.

I'm afraid that's wrong. What he's saying is that he considers the system to be faulty because it doesn't provide the level of performance that he expects. That is not the same thing at all.

If the system then responds by reversing its behaviour entirely and heating instead of cooling, then it is badly designed. As you have in fact described:

Yes it is, but the design fault is not with the HVAC because these installations work perfectly adequately in sealed rolling stock. The design fault was in not sealing up the windows.

There are two points here. Point one is that the thermostat is wrongly positioned. It should be located so that it detects a temperature which is representative of the carriage as a whole. Since it evidently does not do this, the design is bad. The thermostat does not have to be adjacent to the rest of the gubbins; it can be anywhere you can run a wire to, but someone would have had to think about that and they couldn't be bothered.

And where should that be? At the top? The bottom? Maybe it should hang from a wire in the dead centre of the saloon like a bathroom light-pull.

The issue here is that you are repeating the mistake of failing to understand how HVAC systems operate and why the thermostat is located where it is. It's really just Physics 101. Cooler air is more dense than warmer air and will sink to the bottom pushing the warmer air up setting up convection currents which draw the warmer air up towards the HVAC intake. Once the top layer of air (which is the warmest) has reached the pre-set temperature threshold the HVAC system will stop cooling but continue to "condition" and circulate the air. Therefore you want the thermostat to be at the top along with the rest of the HVAC plant because that is the highest point reached by the convection current.

Point two is that the hopper vents are also badly designed, because they do not direct the airflow to where it is needed, but send what flow they do manage to admit in a direction that does no good (aircon or not). As of course we all know if we have ever tried to achieve decent ventilation using them...

On that we agree. Hopper vents are only really effective when the train is in motion and were not intended to give spot cooling at any given location but rather to provide cooling and ventilation to the entire vehicle. But in that respect, they are not so much worse than the sliding toplights that preceded them.

The system is not "working perfectly"; it is failing at multiple points.

Correct, and primarily because of passenger action.

You are entitled to disagree if you feel so inclined, but I have proved this for myself on the Cl317/7 units which had A/C and opening hopper vents. The HVAC works perfectly just so long as you keep the windows closed. Even when you open the windows the HVAC is still operating correctly based on the inputs that it's receiving, it's just that the conditions inside the coach mean that it is hoodwinked by the airflow coming in through the vents.

There are other reasons for opening vents than simply trying to adjust the temperature. It's nice to have a bit of fresh air when the weather allows instead of stuffy stagnant muck. Also, there is a roughly even chance that someone in the carriage will be drenched in some chemical warfare agent; it only takes one, and the choice is to open a window or feel ill all the rest of the day. The loss of decent openable windows is a significant factor in why train travel these days is much less pleasant than it used to be.

I can only presume that you do not travel on rolling stock with sealed windows, then. Given the lack of any equivalent threads bemoaning the inefficiency of the HVAC systems applied to sealed window stock I can only guess that there is not a general concern about it's operation. By all means open the window if you wish. Just be aware that doing so will affect the HVAC and likely make your journey less pleasant.

Oh, and you do have a third option. You could always move away from the person you are objecting to into a different part of the train, something that might also aid you with your radiant heating issue.

 

[Bluejays]

Agree re the hoppers getting opened too early quite often, really frustrating when the ac is working . Too many of the hoppers are loose and blow open, especially when in tunnels .

I wonder if some of the reason for the better ac performance on Chiltern units may be the difference in livery. Reflective white for Chiltern, dark green/blue for gwr. Not sure how much of a difference that makes in practice

 

[Bletchleyite]

Agree re the hoppers getting opened too early quite often, really frustrating when the ac is working . Too many of the hoppers are loose and blow open, especially when in tunnels .

I wonder if some of the reason for the better ac performance on Chiltern units may be the difference in livery. Reflective white for Chiltern, dark green/blue for gwr. Not sure how much of a difference that makes in practice

OK, they don't have aircon, but the paint colour makes enough difference that London buses have white roofs for exactly that reason.

 

[fgwrich]

Agree re the hoppers getting opened too early quite often, really frustrating when the ac is working . Too many of the hoppers are loose and blow open, especially when in tunnels .

I wonder if some of the reason for the better ac performance on Chiltern units may be the difference in livery. Reflective white for Chiltern, dark green/blue for gwr. Not sure how much of a difference that makes in practice

A wonderful heat absorbing Matt Black for the roof of the GW units. A huge case of style over functionality there.

 

[northernbelle]

Agree re the hoppers getting opened too early quite often, really frustrating when the ac is working . Too many of the hoppers are loose and blow open, especially when in tunnels .

I wonder if some of the reason for the better ac performance on Chiltern units may be the difference in livery. Reflective white for Chiltern, dark green/blue for gwr. Not sure how much of a difference that makes in practice

Yes, it probably does make difference although the 165 air cooling equipment seems to be solid enough to counter the dark coloured roofs. Lesson on roof colour learnt on later repaints such as the 769s although the original reason for the black was to hide the exhaust staining on diesel stock. Even the well-presented Chiltern fleet can suffer from filthy roofs at times - and it does matter, given the number of overbridges at stations. Often a passenger's first view of their train at, say, Reading, is the top of it!

On some stock, such as Voyagers, IETs or Desiros, the air conditioning equipment is well-enough engineered for the colour not to matter.

 

[Mikey C]

I was on a 375 returning from the coast yesterday evening, and noticed that one carriage had its emergency hopper windows open. A localised fault I assume?

It's wasn't hot by that time, and there was no way as a passenger of shutting them without the key

 

[RPI]

Noticed several of the 166 units have notices in the cabs now saying that there is a rolling programme of the air con being upgraded and not to open the windows too quickly, in fact, every one I've worked this week has had working Aircon! Apart from one set where one coach was like an oven

 

[gallafent]

Noticed several of the 166 units have notices in the cabs now saying that there is a rolling programme of the air con being upgraded and not to open the windows too quickly, in fact, every one I've worked this week has had working Aircon! Apart from one set where one coach was like an oven

I'm reminded, for some reason, by this, that it used to be the case that the doors would automatically close after quite a short time when the train was standing in a station, as long as nobody walked through them (and broke the beam that shone across the door aperture at floor level, I think!) …

I now realise that when I've been on one in recent years this hasn't been the case: once the doors have been opened they stay open until someone closes them. I assume that this is just because it has failed, in general (or maybe been isolated on all units after failures on some, …).

Clearly, the automatic closing would make the job of the air conditioning / air cooling / heating a lot easier (as well as making sitting in the train when stationary in a station generally a lot more pleasant) … I wonder if it can be reinstated / repaired. Or is it in fact still working fine on most units?

 

[Bletchleyite]

I do not recall these units ever doing that.