Dual-zone AC in camper van

[Gerrbear]

Thanks for that. I see your point now. Would a condenser under the van work? I have seen that done before, and I would prefer that as I use the luggage rack pretty often. If not, I will look into a single evap/blower system with ducting/fans for distribution.

Question about air distribution: If I was to have the evap in the back, under the rear seat (where there's lots of room), do you think a fan in the back, pushing the cold air into ducts that run to the front of the van (maybe under the floor) would be adequate, or would I need a fan in the back pushing and another fan in the front pulling?

Thanks again, I'd clearly have no chance of success on my own.

[Cornbinder89]

To be honest, I don't know. If you have a factory heater and blower under the dash, There might be a way to unitize that as you "booster" blower, and would allow for use of the existing air ducts.
Booster blowers are a lot cheaper even if you had to buy one new, then another evap.
The advantage of evap under the rear seat, is the return lines are short, which is good, and you can leave the stock heater under the dash if so equipped.
Even if you end up needing a 2nd evap, if you start with one under the rear, you can decide what you are willing to give up in the front if you need too.
The only draw back of the rear evaporator is: It most likely wouldn't draw outside air, but only inside.
As far as where to place the condenser, anywhere with less the ideal air flow to it will reduce its capacity. It is why in the early years of truck A/C roof mounts were common, it is the ideal place to put a condenser, it gets plenty of ram air and doesn't get hot air just above the pavement. Air that comes a few feet above a black surface can be heated far above what open air is.
Behind the grill is not ideal, but is a compromise. It is cheaper to place where one fan can cool both it and the radiator, and air flow has already been analyzed.
Placeing the condenser under the van would be a bad idea from many angles. 1st the risk of damage, 2nd it wouldn't be 90 deg to air flow, so air flow would be a problem and 3rd the above about heat off the pavement.
Air ducts under the floor are ok but you want to insulate them so they don't absorb the road heat.
As I said, there is going to be a lot of experimenting to find what works best. I like the idea of one evaporator in the back, then add on to that to try and find what works. An add on blower (push from the back, draw from the front) IE rear blower into the suction of front blower) with some sort of flow divider to supply the rear seat passengers.
Espar and Webasto sell a lot of ducting supplies, Y's and control doors that might work well. Look on E bay for ideas..

[Gerrbear]

Awesome, thanks. I've been talking with suppliers and others and I think I've got enough to get started now, so I'm going to start ordering parts. Thanks for your help. I'll post some updates as I go.

I'm going to start with a rad mounted condenser that others have used with success on dual Evap systems, and run two evap systems (not sure which ones yet, still talking to suppliers).

I could easily add a fresh air intake to the rear system (I will have one in the front to improve my defrost) as there is an intake for the (now removed) furnace. I would have to add a cabin filter to it though, as it would pull air in from above the rear wheels and it would be really dusty without it. Is it worth it, you think?