Technical question-Thinking about A/C

[Will]

I am wondering what do you all feel would be the FE damage drawing 115V and 2.4A with inverter? I am looking at possibly using an AC designed for a cubicle (150sg ft).

This Tennessee summer is frying me like an egg.

[dremd]

In what vehicle?

115*2.4 = 276 watts

I doubt that would cool a car very much; but it also wouldn't hurt milage all that much either .. . . .

[azraelswrd]

An A/C unit will need to dump the heat somewhere... which makes me think it won't be as helpful as it can in such an enclosed space as a car. If humidity is a problem, I'd use the in-car A/C sparingly. Otherwise if humidity is low, a portable fan that uses less power/generates less heat would be my option.

But then again, you look like you're doing pretty well on MPGs. A little AC and/or window crack wouldn't hurt in small doses.

[Will]

Oh, it would be the Metro, which has no AC at all. Humidity is a big issue here, especially in the summer.

As far as the heat goes I think I would dump it out the back like the Aptera T1 does. The ducting would be tricky, but it's an idea. The biggest thing I was worried about was the FE impact. I will get with the mfg. of the unit to see about how effective it would be.

[azraelswrd]

Another option is a portable dehumidifer. That way, standard evaporative cooling methods will work though I can't say for certain how effective/quickly the dehumidifiers are at sucking out the moisture. But if you've got a plan for dumping the A/C heat out the back why not.

[justpassntime]

Originally Posted by Will

I am wondering what do you all feel would be the FE damage drawing 115V and 2.4A with inverter? I am looking at possibly using an AC designed for a cubicle (150sg ft).

This Tennessee summer is frying me like an egg.

Sorry Will,

I got this really funny vision in my head of this Beverly Hillbillies vehicle going down the road with a air conditioner hanging out one window, a stove pipe out the other for heat on cooler days.

Oh...and as for the egg thing...not surprised have you looked at your avatar?

A slightly more serious thought....

Would putting one of those neck cooler things you soak in water hung in front of the center vent make any difference in temp? They retain water well and should work like a small evaporator system, but probably not enough to notice. Need for more ducting or stove pipe.

[MetroMPG]

Originally Posted by dremd

115*2.4 = 276 watts

I doubt that would cool a car very much; but it also wouldn't hurt milage all that much either .. . . .

Oh, I disagree! Adding a 276 watt load will definitely show up at the gas pump on a Metro. I gained 10% better fuel economy @ 70 km/h by removing a 288 watt load (estimated, admittedly) from my car's engine.

[johnmyster]

Problem being, an a/c unit designed for a 120 sf office space would never make a dent in cooling a car. A major climate control efficiency effort on a car could and should concentrate on insulation and making the cabin more airtight. So much heat comes through the floorpan and firewall. So much heat comes in from sunlight through the windows. So much conditioned air is lost through the door panels, that our CC systems have to work far harder than is really necessary.

[klrv6]

Are your windows tinted? I always get mine done and it helps dramatically. Look into 12v brushless fans like those found in cooling computer cases. They draw next to nothing at 12v

[johnmyster]

My windows are tinted, and yes it helps. FWIW, I have a '98 Sonoma, 4 cyl, manual, extended cab. Approx 31 mpg on the highway, but only with the windows down, no AC. AC drops to around 27. Soon to come are an electric fan and underdrive pullies, we'll see if that helps any. Based on my driving, I could probably drop to 3.73 gears from 4.10s as well.

I'm not worried about the electrical load posed by my blower fan. Ususally with max ac the lower two speeds (of four) are enough to keep me cool on long road trips. I am more concerned about compressor drag on the motor. On those same trips, the floor pan gets really warm. There's got to be 50 sf of floorpan on my truck, and at that temperature, you're picking up a lot of heat through it. Easily 300 to 500 watts or more. Even my shift lever gets pretty warm from the tranny. AC has to overcome all this. Then, as your AC is working, a lot of the cooled air ends up flowing out the doors rather than being contained. If these issues could be addressed, you could easily get by with a much smaller AC system - with a smaller compressor that would pose less load on the engine. Even with the same system, your compressor would cycle more often, putting less drag on the motor if it didn't have to work as hard to keep the evaporator coil cold.

Exhaust wrap and heat shields under the floorpan? Additional layers of carpet, rubber matting, and padding? Sealing off your doors with significant levels of duct tape under the door panels? Installing a valve under the hood to bypass the flow of coolant into the heater core? Perhaps these are the latest ecomods for those of us who occasionally require AC.