Roof vs Cruise air

[johnklopp]

Jack,
Great photos, I always wondered what the CA units looked like. Lets see, if I go to Home Depot and get a window unit then saw off the evaporator end ......

[phorner]

Just a quick note about the performance of CruiseAir units. We are currently in South Jersey where we are expecting triple digit temperatures over the next several days.

Current stats are:

Outside ambient temp. 96

Heat Index 100

Inverter Bay temp 103

Inside bus temp 70 ............. and dropping!

I don't know how this would compare to a similar bus with 4 roof air units, but I am quite pleased with the performance of my CruiseAir units. Four are running as a test. I could probably stabilize the inside temps in the low 70's with three units running, holding one in reserve in the event of a unit failure or increasing ambient temperature.

IR temp of discharge air from the CruiseAirs range from 55 to 59 degrees.

I'll be looking for a sweatshirt soon

But I don't think the campground owner will be happy when he gets the electric bill for our site ......

[jack14r]

I did order a new blower that is 6.75 OD X 5.625 W and I checked 6 places on the condenser before and after installation and the wind speed was increased about 10% the amperage on the motor was 1.5 amps which is 25% higher,this is still far below the 3.0 amps the motor is rated for.The force of the air at the exhaust is obviously much greater.

[johnklopp]

Jack,

Great job and good data with photos. Please add the vendors name were you got the blower wheel and the part number. I'm sure some of our fellow members with CA will be considering your upgrade, approximately how long did it take?

[jack14r]

Thanks John,I purchased it from blowerwheel.com item #06240520-016-s-t-di-ccw-01,the fit is tight so we trimmed the housing a little at a time,the time on the first one was 3 hours but I could do the next one in 1 hour,the problem is you must have the CA on a bench.In a couple of weeks I will install the unit in the bus and report how it works.I have an extra CA condensing unit which made this all possible.

[jack14r]

Can anyone guestimate how much airflow would increase if the rpm was increased from 1625 to 1725,and what horse power would be required?

[phorner]

As a very rough guesstimate, if the CFM of the original blower is known, I would increase it by the percentage change in RPM. However, that does not consider the larger cross sectional area or surface area of the blades.....

[johnklopp]

CFMa = CFMb X (SIZEa / SIZEb)3 X ( RPMa / RPMb)

Hpa = HPb X ( SIZEa / SIZEb )5 X ( RPMa / RPMb)3 X (pa / pb)

[phorner]

John,

Thanks,

That's exactly what I meant.....

[gmcbuffalo]

I check the air temp coming out of the evaporator by putting a refrigerator thermometer to the grill. Before 70 deg F. With the AC on full fan 47 degs, turned on the aux fan 49 degs. So with the bus standing still the fan is a negative help. Maybe it will help while on the road. But I was impressed with the drop in temp.