Getting a good night sleep in an off-road caravan in Northern Australia requires special air-conditioning. One of the biggest issues with caravan air-conditioning is the noise. Roof top air-conditioners are like the old "window-shakers" with the compressor housed together with the fan system.
Kimberley have introduced the innovative "split air-conditioning" to caravans with excellent results. The noise level drops to a low 68dB when measured less than a metre away from the air handling unit (see photo). To put this in perspecive, 70dB is the noise of a telephone ringtone and this air-conditioner is less than that at 500mm.
Split air-conditioners are considered the best technology in homes today. Split systems are efficient and much quieter. So why cant people have this modern technology in caravans? Window-shakers and noisy rooftop units have to be relegated to the past.
Lets explain in layman terms the elements of an air-conditioning system: There is an air handling fan which blows the air over a cold "coil unit" into the caravan space. There is a compressor that creates the cold refridgerant in the coil unit. Whilst both the compressor and the fan create noise, it is the compressor that is particularly noisy. To reduce this noise, split air-conditioners move the compressor some distance away from where you are trying to sleep. In the caravan, Kimberley move the compressor to the very front of the caravan in a separate storage compartment. You can see this in the photo below.
In the field test, this reduces the noise level to as low as possible.
One of the other factors favouring split air-conditioners is the efficiency. Efficiency increases significantly if the compressor is loacted in a cooler area with easy air-flow. A hot roof top loaction reduces the efficency of the compressor compared to a cooler location under the caravan. Air-flow is critical though.
Rooftop air-conditioners are particularly in-efficent when heating. Most units use a simple "heater wire' with air flow for heating and consume more power heating than when cooling. Kimberley use their existing diesel hot water unit and a heat recovery system for internal heating. Tis frees the air-conditioner for cooling only. The heating system can operate with a much quieter fan. The heating system also doesn't need a generator and can operate all night with no noise heard from any neigbours in a National Park.
The image on the right show the compact nature of the air-conditioning fan unit and the air-heater unit in the Kimberley Karavan. The air return located on either side of the galley, is just as important.
A variable fan speed is also important and the unit Kimberley installed has a 3 speed fan.
The photo shows the location of the sound evaluation within 500mm of the fan handling unit. The bed is off course above the fan handling unit and so even quieter that the meter reveals.
The photo below shows the compressor unit located in the Karavan multi box which is a separate enclosure to the main Karavan. There is sufficent room in the Multi-box to store a 2 kW generator. The compressor vents to the rear and accepts "compressor cooling air" from the front.
There are 2 other major benefits of this split system:
- There is less drag on the caravan because there is no bulky device on the roof. This gives improved fuel consumption.
- The lower roof height means the Karavan can fit under a 210mm garage height.
The specification is: Cooling capacity 2.2kW. Air delivery is a maximum 110 litres per second.
In the Kimberley Kruiser, this unit operates from the 12V battery system without a generator.