AC tropicalisation modification help

[ymfox]

Good evening gents.

I need some expert technical advice please:

I built a motor-home on a 7,5 ton Mercedes chassis. It now measures 9 metres long x 2,4 metres wide x 3,9 metres high. I have 6 x 250 watt solar panels plus a pure sine wave inverter and all the paraphernalia to go with it. I am going out to the middle East where the temperatures are between 40 and 50 degrees C. I have a Hitachi inverter split A/C that is designed to function till 42 degrees C. I am looking at options to tropicalise my AC. I'm not sure the best way to go about it and am looking for your advice please. I have an idea in mind, but it may be far off the mark as I've no experience designing AC systems... Install an in-line sub-condenser (approx 1/4 to 1/3 the size of the original) the fan motor for which is speed controlled via an HP pressure sensor??

Am I anywhere near the mark or just plain loony?

Best regards

Yasin

[install monkey]

leave it and prey the ambient is under 40 deg
otherwise spray water on condenser
give the mrs something to do whilst she's gettin a tan:D

[The Viking]

Yasin,

It all depends on what experience / expertise you either got or have access to...

Yes you could put a second condenser in the system, you could also replace the existing condenser with a larger one or even beef up the fan to increase the airflow across the condenser. All these solutions got their own limitations and disadvantages, the main limitation for all these solutions is likely to be that they need to be designed by someone experienced in doing so and the system modified by an engineer with a F-gas ticket (but so does the installation of the rest of your system)

The easy option is to do what Mr Monkey says, water spray.
As water is a commodity where you are going, I would suggest that you opt for a recirculating spray system. A small pump to pump water from a container below the coil to a pipe with small holes in at the top of the coil wetting the coil, then a tray (or the base of the outdoor unit) collecting excess water below the coil and returning it to the container, the condensate from the indoor unit could also be routed to the container for recycling of the water.
More complicated wetting systems are available, search for Ecomesh to see one example. These will hold the water away from the coil, causing less longterm damage than if the water is flowing on the coil itself.

Whichever option you go for, the main limiting factor is likely to be the cost. If you opt to modify the refrigerant circuit it is likely to cost way more than just buying a complete ac system designed for usage in the Middle East in the first place...

:cool:

[assailant]

spraying water over the condenser coil when the temps exceed 40+degrees is going to chew through your water supply in no time flat...
consider that it can easily be 5%RH and 40+, you can say see ya later to your tank full of water.

<edit> i should have mentioned, we have installed hundreds of hitachi splits and it summer time maximums regularly exceed 40degrees and we have no troubles.. the units will lose some capacity but its not as though they stop running.
i wouldnt be too concerned about it, the easiest thing to do to prepare for those conditions is to size the system appropriately. you may want to consider 180 - 200W of cooling capacity per square metre as a guide.