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.