A rare Liberty

[rfoster]

Jon. Sounds like i will have to reorder more funeral home fans.

[jack14r]

Roger,Make sure that they come with plastic roof covers.

[Jon Wehrenberg]

Jon. Sounds like i will have to reorder more funeral home fans.

Hey King......I tried to make that post OTR neutral. It's all kind of a moot point anyway because once Liberty stops building them with OTR it's all over.

[phorner]

Sounds to me that OTR buses have become value-added buses!!

If you want a bus with real, Prevost-factory-installed Over The Road bus air, it looks like your choices will be diminishing as the years go by.

Hopefully that will mean that the surviving coaches with OTR will see a premium attached to their value.

[Jon Wehrenberg]

I suspect there will always be a premium attached to an OTR coach. I have never seen an OTR coach for sale on sites that offer a description of the coach in which an OTR coach was not described as having OTR. Nobody ever says "this coach does not have OTR so it has extra storage space."

Seated coaches are always going to have whole bus heat and air which means Prevost is always going to build coaches with it. The question is if it will be available on conversions. If so a buyer could special order it.

[johnklopp]

I’m putting my 2 cents into the ring without any knowledge of OR air beyond what I have read on this forum and knowing that I may have just thrown myself under the bus so to speak.

I’m not sure if over the road air is really needed or not. It appears based on the comments from many POG members that it is desirable and may even increase the value of a coach. The application sounds like there is only one evaporator requiring a large blower to circulate the air through ducts taking a substantial amount of space.

If that’s indeed the case, from my perspective OR air is a major waste of space.

Has anyone considered why your coach is heated with circulated hot water modulated through fan coils to provide multiple zones of heat with individual zone control? Why doesn’t the OR just have a single hot water coil to heat all the areas with the same air flow that is used to cool the coach? The reason is simply better zone temperature control.

A single evaporator with a large enough blower to circulate the air would be substantially larger than a refrigerant to water heat exchanger. A 10 ton refrigerant to water heat exchanger would be approximately 6 x 12 x 18 inches and be connected on the refrigerant and water sides of the heat exchanger by tubing less than 1 inch in diameter.

A simple system would use cooling heat exchangers with drip pans similar to the ones used to heat the coach with the Aqua Hot boiler. Cold water would be circulated with one or more pumps and the zone temperature controlled by modulation valves on each zone fan coil.

A more complex system would use the same or similar heat exchangers and existing tubing distribution system currently used to heat the coach. The pumps used on the Aqua Hot system would be used to circulate the coolant with automatic isolation valves to eliminate mixing of hot and cold coolant.

It’s not a radical idea. It just hasn’t been done on a bus, yet.

[johnklopp]

Note that if the above liquid cooling system were employed, the same cooling circulation pumps, tubing and cold water to air heat exchangers could easily be connected to a CA units producing chilled water instead of cold air. All of the remote CA evaporators and air distribution ducting would also be eliminated.

[Jon Wehrenberg]

Simplicity......I think OTR is designed as it is because for a commercial coach to be practical it needs fast turn around in service work. The OTR as built is centrally located and the condensing side, evaporator side and the compressor are all accessible by opening a door.

For heating in my Liberty I can use the OTR system which is a whole coach system with one set of temperature control, or the Webasto which has multiple thermostatic controls. When the coolant is heated the Webasto burner never fires, but the heated coolant from the engine is circulated through the various heat exchangers throughout the coach.

As to using water for condenser coolant don't we still have the problem of getting rid of the heat the water has absorbed? Using water cooled CA condensers would be easy because they are located in two general areas so plumbing would not be excessively complex, but the heat still has to be removed from the water.

[truk4u]

I wanted OTR this time around since the Cruiseairs will shut down in the heat and the dash air just can't keep up. Now that I have this Royale without OTR, it's really not needed. Last week was the heat test, 95 degree's and Ms Truk used a blanket for part of the trip. Royale adds a 2nd evaporator and fan in the overhead above the driver and with both dash and overhead airs running, we were very comfortable and no need for the gen and roof airs.

Just one more example of how the various Converters did things different.

[GDeen]

To John's very knowledgeable and technical based post....

OTR is a bludgeon with which to cool or heat your bus. No real zonal precision to it (aside from the driver/coach split). In the summer, just turn the goodie knob to cold or colder, and the fan knob from low to high. I imagine that is rooted in simple motorhome adaptation from seated coaches for which it was employed.

I love having that hammer particularly in the summer. Nothing like pulling into a rest stop in July to walk his royal highness, and having the sunglasses fog over immediately upon stepping out in the searing heat.