Add on electric air conditioning

My principal advice would be that you need to get the second alternator - any electric A/C is going to tax your alt considerably.
 
This sounds great. Electric air is nice when you want to cool the cabin down before jumping in. I would evaluate your electrical load before installing the second alternator.

Kevin
 
I would evaluate the load, in order to decide how large an extra alternator I was going to add... not whether.
 
45 A is a big load. Definitely need a 2nd alternator for that.

Something in their numbers doesn't add up though. They claim 12,000 BTUH cooling, which doesn't square with 45 A @ 28 VDC.
 
Trapper John said:
45 A is a big load. Definitely need a 2nd alternator for that.

Something in their numbers doesn't add up though. They claim 12,000 BTUH cooling, which doesn't square with 45 A @ 28 VDC.
Click to expand...

I know a little bit about electrical but not a/c could you explain? Seems like a reputable firm... really hoping for someone that has has one, maybe they can give me some references???
 
Bluebird said:
I know a little bit about electrical but not a/c could you explain? Seems like a reputable firm... really hoping for someone that has has one, maybe they can give me some references???
Click to expand...

It's probably safe to say that any company that is going to go to the effort to bring a product like this to market is going to make sure it works well. And I'm sure they'd provide references for their satisfied customers.

I'm not an HVAC engineer, but in residential systems, a fair rule of thumb for power consumption is about 7 amps at 240V per ton of cooling. 12,000 BTUH is 1 ton, so that works out to about 1,700 Watts. 1,700 W / 28 V = 61 A or so. And that's running load Amps, starting current is going to be quite a bit higher. Plus there's going to be some current draw for the condenser fan and the evaporator fan.
 
Last edited:
I used to rent a 2008 T182T with the Kelly A/C and I loved it. You get a second alternator as part of the install, so electrical load is a non-issue (plus you get a backup alt.). Kelly does a better job of placing the vents in the headliner as opposed to the console (you keep the cup holders). Flying around Dallas in August with long ground waits and low altitude restrictions was so nice.

Also, if you have your own hangar the ability to ground cool prior to startup is awesome.

BTW I had a primary alternator fail on the above aircraft in Taos, NM (no mechanic on the field). It wasn't a problem since I had the Kelly backup alternator so I just flew down to Double Eagle and got it fixed (nice feature).

To bad they don't make the system for more aircraft.
 
Alexb2000 said:
I used to rent a 2008 T182T with the Kelly A/C and I loved it. You get a second alternator as part of the install, so electrical load is a non-issue (plus you get a backup alt.). Kelly does a better job of placing the vents in the headliner as opposed to the console (you keep the cup holders). Flying around Dallas in August with long ground waits and low altitude restrictions was so nice.

Also, if you have your own hangar the ability to ground cool prior to startup is awesome.

BTW I had a primary alternator fail on the above aircraft in Taos, NM (no mechanic on the field). It wasn't a problem since I had the Kelly backup alternator so I just flew down to Double Eagle and got it fixed (nice feature).

To bad they don't make the system for more aircraft.
Click to expand...

Perfect that's what I was looking for... sounds like it works as advertised. With the added bonus of the second alternator. Thanks for your help
 
Trapper John said:
It's probably safe to say that any company that is going to go to the effort to bring a product like this to market is going to make sure it works well. And I'm sure they'd provide references for their satisfied customers.

I'm not an HVAC engineer, but in residential systems, a fair rule of thumb for power consumption is about 7 amps at 240V per ton of cooling. 12,000 BTUH is 1 ton, so that works out to about 1,700 Watts. 1,700 W / 28 V = 61 A or so. And that's running load Amps, starting current is going to be quite a bit higher. Plus there's going to be some current draw for the condenser fan and the evaporator fan.
Click to expand...

Thanks for your help, very good info
 
When I lived in AZ drying the air out was not something that needed to be done as in typical AC. What you need is an evaporative or swamp cooler. Why not just get one of these to put in the baggage area and also keep your lunch and beverages cold at the same time -
http://www.swampy.net/m300.html Way cheaper and no additional alternator.
 
Art VanDelay said:
When I lived in AZ drying the air out was not something that needed to be done as in typical AC. What you need is an evaporative or swamp cooler. Why not just get one of these to put in the baggage area and also keep your lunch and beverages cold at the same time -
http://www.swampy.net/m300.html Way cheaper and no additional alternator.
Click to expand...

Latent and sensible BTUs...
 
Art VanDelay said:
When I lived in AZ drying the air out was not something that needed to be done as in typical AC. What you need is an evaporative or swamp cooler. Why not just get one of these to put in the baggage area and also keep your lunch and beverages cold at the same time -
http://www.swampy.net/m300.html Way cheaper and no additional alternator.
Click to expand...

I own and use one of these but they work very short term (there is another thread on just these). They do work good for short trips if loaded with almost all block ice, very little water and used only for climb and descent. Once you arrive at your destination you have to find ice, drain and load cooler... not bad if you rent a car or use FBO loaner for short stay.
 
Bluebird said:
Perfect that's what I was looking for... sounds like it works as advertised. With the added bonus of the second alternator. Thanks for your help
Click to expand...
...and the added bonus of dealing with Kelly Aerospace.....not.
 
Trapper John said:
45 A is a big load. Definitely need a 2nd alternator for that.

Something in their numbers doesn't add up though. They claim 12,000 BTUH cooling, which doesn't square with 45 A @ 28 VDC.
Click to expand...


Right, it doesn't match up. I don't see where they claim BTUH but simply "BTU's of cool air". No time reference. I suppose this is a trick marketing claim. The 33A of run power is about 1KW of power which is equivalent to about 3000 BTU's per hour. So, to get to 12,000 BTU's, it would have to run for 4 hours. Perhaps that is the flight time they are basing the claim...
 
12000 BTU would be probably be peak capability of compresor/evaporator, figure they are averaging the 45 amp load (peak amp load would have to be higher for 1 ton compressor), and including thermostat switch cycles. Also, they could delete the fan which would save a few amps, if they were smart enough to pick up air from the front of the aircraft. Either that or they are lying, which seems unthinkable :)

How much are they wanting for this thing? If it were me, i would just climb to 9-10k and open some vents. Plenty of cool air up there.
 
skidoo said:
Right, it doesn't match up. I don't see where they claim BTUH but simply "BTU's of cool air". No time reference. I suppose this is a trick marketing claim. The 33A of run power is about 1KW of power which is equivalent to about 3000 BTU's per hour. So, to get to 12,000 BTU's, it would have to run for 4 hours. Perhaps that is the flight time they are basing the claim...
Click to expand...

Wrong conversion factor. Your calc demonstrates how much *heat* the could deliver by electric resistance heating with a kiloWatt. But heating and cooling are different, or none of us could afford to cool our homes.

With cooling, we're transferring heat, so it comes down to mechanical efficiency. The unit they used is designed for chilling server racks. Very efficient, and hence much more expensive than a home chiller.

Personally, I'm considering gas fired ammonia cycle chilling for our next home. Thermal solar can drive it as well.

Paul
 
You must log in or register to reply here.
Back
Top