Mixing/connecting cooling systems

[Tim Strommen]

Interesting application...  Here's a suggestion though: put in a smaller genny for non-"production" loads.  When you kill those follow spots and floods, the load on the genny will drop by around >=25%...  Since you mentioned follow spots I'm guessing that you are also planning on running some live sound reinforcement amps/speakers.  Those systems draw >1KW meaning your design peak power draw is probably way higher than your average draw...

So it may be in your interest to run the cooking, heating/cooling (HVAC&R), internal lighting etc from a 6-12kW genny and wire your extra cooling/heating to the large genny so it'll run when your roadshow loads are running (I still can't get over the moster system you're putting in  - I thought mine was big...).

-T

[PCC]

Again, I have to lean heavily on the "steal" of a deal that I got on the generator itself. It fits under the bus, and will power everything.

Yes, there will ultimately be a major P.A./sound system, and having been a recording and concert sound engineer, I will want more available amplification than I need. (Turn my system up with some old time gospel while driving next to some of those loud cars !!). Traveling as a sound guy is where the bus bug bit me over 40 years ago.

The two generator idea has crossed my mind, but I am running out of bays to put more equipment, so I may have to stay with the big one and let 'er rip, no matter how much it will cost to run. (I might be able to drop up to a gas-powered 5 Kw in a corner somewhere, like behind the former washroom tanks door. Another good idea, thank you.) I have no plans for any propane.

That is why I have been trying to figure out ways to heat/cool the coach with a system that would allow multiple ways to turn the A/C compressor - from the engine and also an electric motor, but how big an electric motor would I need to turn the 12.5 ton A/C compressor? That may not be possible, but we are talking about it. I have always wondered if a system can have two independent compressors working the same plumbing for evaporators and condensors. Seems that that is not possible, as far as I know at this time.

I hope to be using my short bay over the drivers as the heating/cooling unit by insulating it completely, sealing it from outside air, and installing the evaporators, hot water (coolant) radiators, electric heating coils, and the fans into this compartment - and it is big enough to fit it all. I am waiting for the final component specifications to confirm that it will all work.

All I know is that the system cannot go on the roof, so I have to fit it underneath, and that one bay is the least intrusive into my overalll designs.

Thank you, and have a great day.

[niles500]

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Yes, there will ultimately be a major P.A./sound system, and having been a recording and concert sound engineer, I will want more available amplification than I need
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With amps like the I-Tech and Digam series along with the new LED stage lighting your power requirements for "mobile" off the grid SSL are a fraction of conventional systems - FWIW

[James77MCI8]

40-50 HP to run the OTR compressor. I would put the small genset in the bus and rent a bigger one if needed at the venue. That is what we did .I once did remote recording and live sound for gospel music venues. We typically ran 10,000 watts for amplification . With everything powered up we could run the system with 5Kw with no problem.

[buswarrior]

James77, which OTR compressor do you mean?

The entire stock HVAC system in the MC7/8/9 and early 102, was considered to be 20-25 HP load at most, compressor and electric combined.

I'm having a hard time keeping track of this thread, so I apologize if I've missed something.

happy coaching!
buswarrior

[PCC]

B Warrior,

If you say it only took, say, 30 HP max, to run (load) your A/C compressor, then would a 30 HP electric motor not also turn that compressor?

I have a motor builder who works to build and rebuild electric anything (motors, generators, alternators, welders, etc.) that works with me (friend/contractor), and he could build me a motor to drive my OEM A/C compressor for when I am not running the main engine?

More ideas???

[Dreamscape]

A 30 hp motor will run you around 2K new, and they are heavy. Then you have to have 240V to run it, 480 would be more efficient. Where are you going to find that kind of power in a bus?

Paul

[PCC]

Yes, Paul, I am the crazy person with the 240 v., 50 Kw generator on board, it fits and was inexpensive, so I have the power. I do not have 480 VAC, though I could wish !!

But am I correct, did you say that the 30 HP motor would run the OEM 12.5 ton A/C compressor? 2K is still less expensive than the cost of the completely new all electric A/C - heat system that I have been considering.

The only consideration would be the start-up load when that 90+ amp motor starts up. I would have to start the motor first, with a heavy flywheel, then connect it (electric clutch) to the compressor, so the motor it is not starting up under load.

Keep talking, I am listening.

[Dreamscape]

It sounds like you need an electrical/mechanical engineer to figure what you are trying to accomplish. That I'm not......... I usually try and run with what I have because it's already been engineered for the purpose. That's just me.

I do wish you luck and I'll continue to read the thread to see the outcome!

Paul

[buswarrior]

For this exercise, you'd want to know a closer answer to the HP requirements, as you don't want a 30HP motor when a 15HP might do. You'll have to go to original equipment manufacturer for the specs.

In my above 20-25 HP estimate, that includes the stock AC having between 2 and 3 HP worth of electric fans running. So the total combined load to the engine, compressor and alternator loads, are suggested to be 20-25HP.

Not difficult to rig controls so that the load comes on after the electric monster motor is running, if that will be a problem.

happy coaching!
buswarrior