Air con for caravan

[Surfer]

We are seriously thinking for purchasing a Dometic Freshjet 2200 air con for our caravan. It has the soft start operation which allows it to start up on sites that only have a 6amp supply so should be okay on the continent. The weight is 32kg which will take us right up to our MTPLM of 1800kg however to make sure that we are within the MTPLM I have ordered a Reich Caravan weight Control. We think the investment of a £105 delivered is worth every penny. We already have the Milenco nose weight unit which has proved invaluable.
Although we may not use the unit every day during the summer, we think it will be of great benefit to our dogs as nothing worse that getting out of an air conditioned car and going into a boiling hot caravan. One of the drawbacks of the ALDE heating system is that there is no blown air channeled around.
Can any one please advise on any drawback son having the Freshjet fitted? Unfortunately I cannot find any reference to the db values.

 

[WoodlandsCamper]

The numbers don't appear to stack up

Cooling capacity 2200 Watt / 7500 Btu/h
Heating capacity 1200 watts
Consumption
(cooling/heating mode) 950 / 1200 watts
Input voltage 230 volts AC/50 Hz
Current consumption
(cooling/heating mode) 4.1 / 5.2 A
Required circuit protection Cooling: 5 A
Heating: 6 A

Cooling capacity is stated as 2200 watts yet current requirement is 4.1 amps. I would have expected 9 amps.

I had a standalone floor standing 1 kw ac unit in my broom-cupboard office (the volume of a small caravan) a few years ago and it had trouble cooling the room and also produced a lot of condensate which required regular emptying. Not sure if I'm comparing like-for-like though.

Edit: the room was north facing so didn't get any solar gain, as a caravan would.

 

[ProfJohnL]

Hello Surfer,
I strongly suggest before you buy an air con unit, see if you know anyone with the model you after and the size of caravan, and try it; I know easier said than done, but as you make the point about the comfort you find with the AC in your car, the caravan options are very different and nowhere near as powerful.

As part of one of my jobs we were trying to develop an AC unit for mobile vehicle applications including caravans. I was involved with trying to find out how effective AC units in caravans were. We failed to find a unit that met out project objectives, quite simply 3kW Max power input was simply not enough to produce the degree of cooling we were trying to achieve.

Using power per volume as the comparison:- a simple but important comparison, the AC in your car will be drawing anything up to 7 kW from the engine, and it only operates on less than 4 cubic meters of car volume, by comparison the habitable volume of a 20ft (6M) caravan will be at about 18 cubic meters and at a maximum of 13A will be using no more than 3kW

Car 1.75kW/M3 vs Caravan 0.17kW/M3

This is not a perfect comparison but it gives you the idea of the vastly reduced effectiveness of caravan AC compared to the car system you have experienced.

You also need to keep in mind, the car in motion is also cooled by the air passing around it, whereas the caravan is basically static when the AC is on, with only the wind if you have any.

AC is an expensive option, and unless you are regularly using the caravan in very hot climates, you need to be very certain of the cost versus benefit.

You know my misgivings about the inaccuracy use of nose weight gauges without height adjustment.

 

[Surfer]

Hello Surfer,
I strongly suggest before you buy an air con unit, see if you know anyone with the model you after and the size of caravan, and try it; I know easier said than done, but as you make the point about the comfort you find with the AC in your car, the caravan options are very different and nowhere near as powerful.

As part of one of my jobs we were trying to develop an AC unit for mobile vehicle applications including caravans. I was involved with trying to find out how effective AC units in caravans were. We failed to find a unit that met out project objectives, quite simply 3kW Max power input was simply not enough to produce the degree of cooling we were trying to achieve.

Using power per volume as the comparison:- a simple but important comparison, the AC in your car will be drawing anything up to 7 kW from the engine, and it only operates on less than 4 cubic meters of car volume, by comparison the habitable volume of a 20ft (6M) caravan will be at about 18 cubic meters and at a maximum of 13A will be using no more than 3kW

Car 1.75kW/M3 vs Caravan 0.17kW/M3

This is not a perfect comparison but it gives you the idea of the vastly reduced effectiveness of caravan AC compared to the car system you have experienced.

You also need to keep in mind, the car in motion is also cooled by the air passing around it, whereas the caravan is basically static when the AC is on, with only the wind if you have any.

AC is an expensive option, and unless you are regularly using the caravan in very hot climates, you need to be very certain of the cost versus benefit.

You know my misgivings about the inaccuracy use of nose weight gauges without height adjustment.

Thanks for the above. Internal length of the caravan is approximately 7m so according to their specs just within range. We are aware that the cost will probably outweigh the benefits, but we are planning to do a bit of overseas travel to south of France or Spain either later this year or next year.
However last year while at Torquay in June it was really very hot and the dogs were rather uncomfortable resulting in us driving around with air con full blast to alleviate the heat. At least it will probably be more reliable than the present Omnivent! :cheer:
BTW we have the Milenco nose weight which is supposed to be the most accurate nose weight available. The Reich CWC is to determine the weight of the caravan prior to to deciding whether to do air con or not. Wife wants the air con, but I am not so sure and dithering as £1645 fitted although a very good price is a lot of nights away. Waiting for Lunar to confirm whether roof structure can take the additional weight.

 

[Sproket]

Surfer

A few years ago when we were at the nec show we looked at the then new Truma saphir, we thought about the same thing for our dogs and we looked at fitting one of these ( due to no extra weight on the roof )

Video

 

[Surfer]

Surfer

A few years ago when we were at the nec show we looked at the then new Truma saphir, we thought about the same thing for our dogs and we looked at fitting one of these ( due to no extra weight on the roof )

Video

Thanks. We did look at those and would prefer the unit lower down, but as we have and ALDE system in the caravan there is no existing ducting and I would think that to add ducting would be an additional expense.
We already have a large solar panel weighing 12kgs on the roof. It is situated above the twin axles and is placed front to back on the roof on the off side. Concern is with adding another unit on top may make the caravan more prone to snaking perhaps?

 

[VIP640]

Surfer,
We have a Dometic B2200 fitted and it really cools our van down and its over 7 mts long, we wouldn't be without it when we go overseas....

 

[Surfer]

Surfer,
We have a Dometic B2200 fitted and it really cools our van down and its over 7 mts long, we wouldn't be without it when we go overseas....

Thanks. At the moment we have never travelled overseas although we have the intention to do so either later this year or next year. The missus actually wants us to emigrate to Spain for the winter, but cost is probbaly out of our reach. :lol: