airconditioning?

Freon is the trade name for the refrigerant R-12 that was manufactured by Dupont. Its replacement is R134a.

R-134a is ozone-friendly because it contains no CFCs. It is also nontoxic and nonflammable, and meets all of the Environmental Protection Agency's criteria for alternative refrigerants. By model year 1995, all new vehicles were factory-equipped with R-134a A/C systems because the production of R-12 was phased out at the end of that year.

 

http://www.denso.co.jp/motorshow/2003/en/p...oduct_electric/

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DENSO is the world's leading producer of car air conditioning systems, with a world market share of 25 percent. Always looking for ways to improve efficiency, DENSO researches technology that will lead to products that not only meet customers' needs, but protect the environment at the same time.

DENSO supplies electric air conditioning systems for hybrid cars, a market that is expected to rapidly grow in the next several years. For the new Toyota Prius, a hybrid car launched in September of this year, DENSO is supplying a high-efficiency air conditioning system equipped with a newly developed electric compressor.

DENSO's electric compressor is driven by an integrated motor and is able to provide air conditioning even while the vehicle is stopped. As a result, in hybrid vehicles with engines that automatically shut down when the vehicles stop, the electric compressor provides a comfortable air-conditioned cab environment in addition to fuel efficiency.

The newly developed electric compressor combines a scroll compressor, a DC brushless motor, and an inverter for activating and controlling the motor. Because of its optimized scroll form, the compressor improves efficiency in compressing refrigerant and reduces energy loss, leading to higher performance.

DENSO also developed new structures and control methods for the motor and the inverter. As a result, the electric compressor is 40 percent smaller and 50 percent lighter than conventional electric compressors - a significant reduction in size and weight. This small compressor can be mounted on the engine while conventional larger compressors can be mounted only on the body. The new Prius has the compressor mounted on the engine.

DENSO has developed and applied the world's first CO2 car air conditioning system using CO2 as refrigerant for Toyota's fuel cell hybrid vehicle launched last December. Through products like these, DENSO continues to lead the 21st century in the creation of comfortable vehicle environments[font=Arial:c851440698] [/font:c851440698][font=Andalus:c851440698] [/font:c851440698][font=Arial:c851440698] [/font:c851440698]

 

http://www.denso.co.jp/AR-e/1998/TW/climate.html

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Air-conditioning systems should not rob torque from hybrid powertrains on hot summer days. And they need to be able to heat interiors on cold days with little help from engine heat. For the Toyota Prius hybrid car, we developed an ultraefficient air-conditioning system (outlet next to Mr. Okabe's hand) that consumes minimal power.

Our new subcool condenser and scroll compressor, equipped with oil separators, allow the air-conditioning system to run on 30% less power than conventional systems. And a two-layer flow heating, ventilating, air conditioning (HVAC) unit saves energy by recirculating heat already in the cabin.

Air conditioners consume as much as 5% of engine output in passenger cars. We are the world's largest manufacturer of air-conditioning systems for automobiles. And we lead the industry in reducing the energy requirements of car air conditioners through improved designs, weight reductions, and new technologies. In 2005, our air conditioners will consume 50% less power than they do today.

The climate-control system we created for the Toyota Prius consumes 30% less power than conventional systems of comparable performance. That improvement in energy efficiency is the result of advances in individual components and--equally important--improvements in overall system configuration.

Modularization contributed to weight savings and also to productivity gains on the vehicle assembly line. We are the sole supplier of the air-conditioning system for the Prius. And we integrated the chief components of the system in compact, easy-to-install modules.

High-efficiency components

Our ultraefficient air-conditioning system for the Prius already is yielding valuable spinoffs. For example, we developed an improved subcool condenser for that hybrid vehicle's air conditioner. Systems equipped with subcool condensers are more efficient in heat exchange, weigh less, and require less refrigerant than conventional systems. Cooling the reliquefied refrigerant further in the subcool condenser reduces power consumption 10%.

Our new SCS08 compressor is another important advance in the air-conditioning system for the Prius. The compressor incorporates an advanced centrifugal oil separator to reduce oil circulation in the refrigerant. That raises heat-exchange efficiency and reduces pressure loss. Oil is necessary for the compressor to operate efficiently. But it lowers heat-exchange efficiency. The refrigerant pumped from the compressor has an oil content of about 4%. But our new separator reduces the amount of oil in actual circulation to about 1%. In contrast, conventional separators reduce the oil content only to about 3%. Our centrifugal oil separator also is much smaller, lighter, and energy-efficient than conventional units.

Concern for the environment spurred automakers to create more efficient engines. But more-efficient engines mean less heat for warming vehicle interiors. Heating units have had to become even more efficient to compensate for lack of the waste heat that conventional systems use.

We have developed a system for the Prius that gets the same performance as conventional systems despite the lack of engine heat available for the system. Ventilation loss--heat that escapes from the cabin as fresh air comes in--accounts for 60% of the heating load placed on air-conditioning systems. Our two-layer flow air-conditioning system recirculates warm air in the cabin to raise heating efficiency.

By using a 50/50 ratio of fresh and recirculated air we were able to reduce the ventilation load 50%. At the same time, we were able to achieve the same cabin temperatures possible with conventional systems. Warm cabin air has a high moisture content. So, simply recirculating the cabin air would fog up the windows. The new system sends recirculated air out at foot level. Drier fresh air flows near the windows, which prevents moisture from condensing on the glass.

Another efficiency-raising component is a new, straight-flow core that we developed for the heater. In conventional systems, engine cooling water flows in a U-shaped route through an aluminum core. We have raised heating efficiency by routing the warmed water in a one-way flow through the aluminum tubing. Our straight-flow aluminum heater core is 22% smaller and 25% lighter than conventional cores.

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.

 

Another Good Presentation:

http://www.epa.gov/cppd/Presentations/Mats...%20inverter.pdf

And Another Writeup - including more on CO2 AC

http://www.ai-online.com/issues/article_de...tail.asp?id=337

 

Wow, thanks Tempus!

Great information!

 

You're going to get hot under the collar if you buy a new Ford Escape Hybrid and turn on the A/C when you're driving in town utilizing only the electric motor. It seems that Ford's A/C doesn't work while the ICE is not running. Can you say oopS!

 

The A/C doesn't work on my Prius either when the ICE is off. The car restarts the engine to run the compressor. Presumably, the same thing will occur with the Ford Escape.

 

The A/C in my Prius seems to work just fine whether the ICE is running or in slo & go Washington DC traffic while running on the electric motor. Kinda sounds like there might be some issues with your A/C system, Wolf.

 

Isn't that one of the differences between the 2003 and 2004 Prius?

Wolf has a 2003 Prius that the A/C stops when the ICE stops.

2004 Prius has electric A/C that runs as long as it has electricity to run it!

 

A/c in Operation

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I normally run A/C at the lowest setting. This cools the interior just fine for me. I pay attention to the ICE and know when it is on. My A/C continues to run with no problems. I live in Northern VA, work in Maryland, and commute directly though the center of DC

 

A/c in Operation

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I normally run A/C at the lowest setting. This cools the interior just fine for me. I pay attention to the ICE and know when it is on. My A/C continues to run with no problems. I live in Northern VA, work in Maryland, and commute directly though the center of DC

 

Surely turning on the A/C will force the ICE to run, as it does in the classic Prius?

 

Nope.

The 2004 A/C is electric so it uses battery power and the ICE will only run to recharge if the battery gets low and isn't recharged by regen.

 

I think he was talking about the Ford Escape Hybrid A/C.

It DOES work exactly like the Classic. Several reviewers have commented on how the engine shutoff won't work in a hot city.

Maybe it's because Ford licensed the Classic Tech? Oh, no, I forgot, they invented it all themselves

 

the compressors don't run all the time in either the classic or the 2k4, if it did the evaperator would probably freeze up. They cycle off and on as necessary for the expansion valve to control the volume of refrigerant to the evaporator. The classic ICE cycles off and on as needed by the compressor. The 2k4 ICE cycles off and on as needed to keep the HV battery charged to run the compressor. Both still need gasoline to cool the car.

 

The 2004 compressor does not need gasoline to cool the car, at least no more so than the radio needs gasoline to play music. The difference between the classic and the 2004 Prius is significant.

 

Which is to say, of course, that both of them do need gasoline. If you never put any more gasoline into your Prius, eventually both the radio and the A/C will stop working :_>