A/C works only when cooling??

<div class='quotetop'>QUOTE(usbseawolf2000 @ Jan 31 2007, 01:11 PM) [snapback]383490[/snapback]</div>

Freon is a trade name for a group of chlorofluorocarbons used primarily as a refrigerant. The word Freon is a registered trademark belonging to DuPont.

To be correct: It was not just Denso. This substance was banned by the Montreal Protocol on Substances That Deplete the Ozone Layer. The treaty was opened for signature on September 16, 1987 and entered into force on January 1, 1989.

I am not trying to be anal here, just wanted to make sure that Toyota or Denso don't get credit for this - they were definitely not first on board with this issue (Toyota was one of the worst polluters in the world in the 60's, 70's and even 80's...)

 

I know this has nothing to do with the discussion, but what the heck.

John in LB, that really is a nice avatar, beatiful colors. I like the reflection of the palms on the car. Great photo!

 

<div class='quotetop'>QUOTE(PA @ Feb 1 2007, 10:33 AM) [snapback]383992[/snapback]</div>

Thanks, but I got it from somewhere on around here, when I registered. It looks close to where I live and the color of my car - so I picked it. Sorry, I can't take credit for taking the photo myself.

 

The Toyota A/C compressor is electric, run off the NiMH battery pack through the inverter/converter. It's variable speed, and if you have the hood/bonnet open with it on, you can quite clearly hear the pitch change as it adjusts to cooling demand.

That said, most automotive A/C systems have thermisters and/or high/low lockout to protect the A/C compressor from abnormal pressure/temperature. Once you get much below about +65 F, "superheat" is almost impossible to achieve anyway.

Ever catch a "technician" attempting to charge a home A/C on a day colder than about +80 F? Well, he's an idiot, because he will never get the correct charge.

http://www.udarrell.com/air-conditioning-efficiency.html

I know with the industrial units I'm familiar with, the control network will "lockout" compressor function if the ambient temp is lower than +55 F, which is considered the lower safety limit for effective compressor lubrication. Let's not forget the compressor oil will settle out if the entire system is much colder than around +55 F. The only exception is if a heater blanket is put on the compressor to keep it warm in lower temps.

Toyota uses the "technically correct" definition of "air conditioning" which is to maintain the correct temperature and humidity within a certain space. This is done by applying heating or cooling as needed, within the safe operating limits of the equipment.

 

I love the electric cooling on this thing!!! Now I only with that I would have ordered this thing with remote start for those 100+ days. oh well, just a side note TOYOTA ROCKS!!! for anyone who didn't already know. B)

 

The Prius does use flex lines to the A/C condenser, so yes there will be o-rings. Could be a lot worse, Ford's A/C systems are assembled with quick-lock fittings, and they naturally lose tension and fail over a period of 5-6 years.

 

<div class='quotetop'>QUOTE(jayman @ Feb 13 2007, 09:23 PM) [snapback]389910[/snapback]</div>

OK, not so bad. It's the shaft seal on the belt driven compressors that I worried about. That damned thing will eventually wear-out if you keep the car long enough.

BTW, are there any belts in the Prius?

 

Yup, for the water pump.

 

<div class='quotetop'>QUOTE(genalex @ Feb 13 2007, 07:38 PM) [snapback]389970[/snapback]</div>

Not for the AC Compressor.

Here is a schematic of the compressor assembly.

 

<div class='quotetop'>QUOTE(seasalsa @ Feb 13 2007, 11:37 PM) [snapback]390003[/snapback]</div>

Yup. That's the classic "sealed unit" compressor design that dates back to early home fridges.

<div class='quotetop'>QUOTE(KTPhil @ Feb 13 2007, 11:36 PM) [snapback]390001[/snapback]</div>

Hmmm. They must have a reason for strapping that to the engine shaft, when an electric motor driven pump would seem so easy and could help sustain cabin heat during ICE-off periods.

 

It has an electric water pump too, for when the engine's not running. Not quite sure why they decided to have both.

 

<div class='quotetop'>QUOTE(KMO @ Feb 14 2007, 01:01 AM) [snapback]390085[/snapback]</div>

Denso says,
"The Prius's main water pump loses its source of mechanical energy when the vehicle is running on battery power alone and the engine is off. So, we developed an auxiliary electric water pump for the car. Our electric water pump provides a constant flow of heat to the cabin even when the mechanical pump is stopped. The mechanical pump operates when the engine is running, which reduces the load on the battery. And a bypass function reroutes water flow to avoid resistance from whichever pump isn't running."

 

<div class='quotetop'>QUOTE(seasalsa @ Feb 14 2007, 08:25 AM) [snapback]390114[/snapback]</div>

The belt and suspenders school of design?
Actually it's perfectly consistant with saving hot coolant in a thermos bottle.