Extending vehicle aircon

[tanuki.himself]

Starting a new thread away from the questions about extending vehicle heat/coolant circuit to the camper....

Could you extend the vehicle cab air conditioning to the camper space?

I'm thinking could you take a dash aircon matrix (evaporator) and blower fan from a scrap vehicle, fit it into the camper and run pipework from the vehicle aircon compressor and matrix (condenser). And coud you use dry break connectors on the pipes to keep the camper demountable?

I'm looking for a cheap. lightweight solution to cool the sealed camper while driving and. more importantly, cool the over-cab sleeping area after sunset before sleeping - should be easy to curtain this off to keep the cool to a confined area. I'm planning on using 12V solar and battery for refrigeration anyway so don't want to add the load of a 12v or inverter aircon unit to that, plus they tend to be heavy and expensive. And carrying a generator is more weight and space...

If you could select between cab dash and and camper aircon matrices with manual or solenoid valves and then just run the engine on idle for half an hour would that do the trick?

or even use the dash evaporator from one of these kits in the camper

https://www.ebay.com/itm/New-A-C-Un...Serpentine-Compressor-CO9537CKB-/173287712010

but still tie it into the existing vehicle compressor and condenser to save weight ....

 

[Neil]

I have thought of this. One observation would be thatcthe evaporator in your drivers cab thermostatically controls the condensor and the magnetic clutch on the compressor.

I think to add an additional evaporator into the circuit is very do able but the one in the living area would simply be a slave to tje one on the front . Ie it would probably have a variable speed fan but lack the thermostatic controlling features. I think you can only have one controller in the system.

Unless someone knows a wzy around it which i would be glad to hear

Neil

 

[tanuki.himself]

I have thought of this. One observation would be thatcthe evaporator in your drivers cab thermostatically controls the condensor and the magnetic clutch on the compressor.

well I guess without the thermostatic control it would just run full blast, which given the size of the camper living space while driving would probably not be a bad thing, and evenings you could just run it until you think it is cold enough and then shut the engine off. The dash on-off switch would still control the function and dial the dash temperature control down to minimum....

 

[FreedomTraveler]

Tanuki,


The Limousine and bus industry has been using systems like this for many years. https://www.infparts.com/store/index.php?route=product/category&path=411_412_525 You can size it for any area you like. Systems like these do require you to extend your AC lines to the new box. ( This would be your toughest job. ) Your existing compressor should be able to push the extra freon. As an example; Lincoln Town Car's stock Compressor is power full enough to move the freon for up to two of these boxes in stretch limousine and still blow out cold air in front passenger area.


I understand you don't want to add a 12V. unit or inverter but for cooling just the cabover sleeping area ( Not the whole camper. ) I am keeping an eye on the Zero Breeze AC units. Right now the reviews are mixed and the price is too high for me but, if they start selling on Amazon, Wal Mart, Etc. ( With easy returns, if it won't work. ) this might be great for just the sleeping area. The testing indicates that the 12v draw is low enough to be powered by a not too large battery bank. ( You don't need to buy there battery. ) There are a few review videos on Youtube.


I have no affiliations with either of these companies, just food for thought.


Good luck and Safe Travels,

 

[javajoe79]

Not sure it matters to the compressor as the hi/lo switch “controls” the compressor. Right?

 

[Sitec]

Have you thought about simplifying the system totally, by separating it... If you are planning on pulling bits out of a car/truck why not pull the whole system out... Have a separate compressor/ac system for the body..? I've bought an ex mine spec coach body and luckily for me it came with an air conditioning system. I plan to mount the huge compressor near/under/beside the existing cab air con compressor and run it as a separate system (switched from the cab) so we can do exactly what you are suggesting.. Cool the living area down before arriving at the overnight stop. Long way off that bit, but it at least a plan!

 

[dwh]

Vans. You can order them with rear heat/air from the factory. For decades now.

https://duckduckgo.com/?q=van+rear+heat+and+ac&t=fpas&ia=web


The disconnect...maybe.

 

[luthj]

AC systems do not tolerate air in them. Plus they are under hundreds of psi. So disconnects aren't really a viable option. Putting another evap in series with the front unit is doable. Electronically controlled variable displacement compressors could be tricky. An expansion valve would be needed, as would a calculation of the extra refrigerant needed.

 

[tanuki.himself]

Have you thought about simplifying the system totally, by separating it... If you are planning on pulling bits out of a car/truck why not pull the whole system out... Have a separate compressor/ac system for the body..?

Problem with that is weight and space. I'm building for a lightweight pickup (Navara. Ranger) so every kilo counts, and i'm not sure how I would get on finding locations to mount a second compressor and condenser matrix. Eventually I'll be using it around europe on proper campgrounds with power hookups so i will fit a normal roof mounted mains unit then, but before that i want to boondock around southern Africa with it, so weight, COG and self-powered are the key criteria, and cheap as its only a temporary solution for a few months....

 

[tanuki.himself]

Vans. You can order them with rear heat/air from the factory. For decades now.

yup. i've seen a load of insulated delivery boxes on the backs of nissan frontier pickups around Mexico over the past few months travelling where they have the evaporator matrix and blower mounted above the cab and pipes going up to it . That is what gave me the idea.....

 

[Joe917]

Cab to cabin access is the cheap answer. We just drive with the door between the camper and cab open.
With a small pick up you could run a 3 or 4" flex to the camper with a fan to push the air and a similar return air.

 

[luthj]

Diverting chilled air via a duct may be the way to go. You could make a system to chill water via the even, and circulate that to a radiator and fan in the back, and use dripless quick disconnects.

 

[tanuki.himself]

Cab to cabin access is the cheap answer. We just drive with the door between the camper and cab open.
With a small pick up you could run a 3 or 4" flex to the camper with a fan to push the air and a similar return air.

Diverting chilled air via a duct may be the way to go. You could make a system to chill water via the even, and circulate that to a radiator and fan in the back, and use dripless quick disconnects.

Might be feasible if I get a truck with an opening in the rear window, but I don't think i've ever seen one of those in Europe. And it would mean trying to chill the whole cab and camper space, especially in the evenings.....

Demount/disconnect for round Africa would be very occasional so maybe a combination of short hoses with screw fittings and isolating valves would work - 10 minutes with a spanner, lose the bit of coolant in the hose and then carry a can of top-up refrigerant. Cannibalise something like this kit....

 

[nathane]

You can get and fit very high pressure dry break disconnects easily. They are used extensively in motorsport in fuel lines and coolant systems. These would allow you to tap into the existing circuit.

Sent from my SM-G930F using Tapatalk

 

[luthj]

An occasional disconnect would be okay. The issue is that each reconnect introduces a bit of air into the system. Air doesn't condense, so it just takes up condenser space, reducing efficiency, eventually it can cause the system to overheat the compressor. Most vehicle AC systems use a variable displacement compressor and expansion valve, so getting the charge correct via gauges is not possible without measure in the superheat/subcool and doing some math. As long as you can keep your refrigerant loss under 20%, you should be okay. You can calculate the loss based on the volume inside the connectors dead space. Hydraulic low loss self sealing disconnects would probably work. They need to be sized to no restrict flow, and have compatible seal materials.

Pressure ratings in the 400psi (in both connect and disconnect) and viton seal materials should be acceptable.