Personal ‘coolers’ are a hot topic now with January among the hottest on record and February set to follow.
West Australian company CloseComfort has released the PC9+Plus personal air conditioner using Aussie patented air delivery technology.
The company claims that the 17kg refrigerated unit consumes 300W and saves up to 75% on power as it creates a micro-climate around you instead of trying to cool a whole room. To use, plug it into a powerpoint and place it 1.5 metres from you.
Before we review it let’s review ‘Personal Cooling 101.’
What all these devices (be they fans, evaporative coolers, or refrigerant based air conditioners like this PC9+Plus) mean by the word ‘personal’ relates to the cubic square metres or litres volume of air they can move and/or cool.
A typical small three-metre square bedroom is about 27m2 and would require a 5-8,000 BTU unit to cool it.
These devices create a small personal cooling zone ranging from about one cubic metre (1 x 1 x 1 metre – good on the work desk) and to perhaps between two and three cubic metres. Each cubic metre contains 1000 litres of air – some brands quote air velocity as litres per second.
Fans don’t cool. They circulate the air at whatever temperature it is. However, the air flow can help to redistribute pockets of cooler air (heat rises and cold falls) and helps to increase the evaporation of body perspiration which gives a limited personal cooling sensation.
Evaporative coolers run water over a membrane causing a heat exchange that converts some of it into cooler water vapour which gives a limited cooling effect. It is most effective in low humidity areas.
Air conditioners use gas or solid-state refrigerant to chill a radiator style of grill. As air passes through the grill, humidity is partially converted into water, so you get colder, drier air.
All personal coolers have a fan. The bigger the fan, the more air it moves and unfortunately the more noise it makes in the process. The fan size must also match the cooling power (BTU) or otherwise all it moves is partially cooled room temperature air.
It is a refrigerated (R134a, 333g), portable floor standing air conditioner on castors – 550 (h), 273 (w) and 385mm (d) weighing 17.4kg.
Setup is easy – there are no external vents or water drainage pipes required. A 2.6-litre water tank collects moisture extracted from the air.
Apart from a hernia-inducing weight, it meets portable definitions.
It is designed to micro-cool an area up to 1.5 metres from the unit. The company claims that it produces about 2500 BTU/hr and up to 3500 BTU/hr in high humidity. The cold air flow is 125 cubic metres per hour hence the term micro-cooling.
The real test of a unit is the temperature reduction from the hotter air input to the colder air output. CloseComfort states a reduction of 8-10° tested at 33° and 80% relative humidity.
Relative humidity measures the actual amount of moisture in the air as a percentage of the maximum amount of moisture the air can hold. Frankly, a measurement at 80% inflates the effective cooling figure as most of Australia cities have a relative afternoon humidity of 40-60%.
Using a Kestrel Drop wireless environmental temperature and humidity monitor we were accurately able to determine cooling efficiency.
The test room was approximately 5 x 4 meters with a standard internal door and external window. The unit was set to cool to 22° and set to mid-level fan:
The external temperature was 26.2° and 45% relative humidity RH
The room temperature before switching on was 24.5° and 45% (RH)
The exit air temperature at the front grill was 11° and 33.8% (RH)
At 1.5 metres in front (micro-cooling zone) the temperature was 22° and 42.3% (RH)
The rear heat exit temperature was 36.7° and 35.4% (RH)
The room temperature(excluding the micro-climate zone) one hour after switching on was 27.6° and 45% RH
We repeated the tests with the outside windows opened . This had the effect of reducing the overall room temperature to 27° and 45% RH. Closing the internal door trapped the heat and the room reached 30°. Neither had any effect on the micro-climate zone.
What does this show?
The Kestrel is highly accurate and used to monitor things like shipping containers, livestock and even cigar humidors.
It showed that the unit had sufficient power to create a micro-cooling zone up to 1.5m depth in front at close to the set temperature. But in doing so, it dumped 36.7° heat into the rest of the room increasing its average temperature.
With the window open it was slightly more effective because it helped dissipate the room heat. A closed room will not change the micro-climate zone but heat the remainder of the room.
Stated noise levels are 46-54 dBA – a theoretical measurement as it is A-weighted meaning a 100dB level at 100Hz will be perceived to have a loudness equal to only 80 dB at 1000Hz. It looks better on paper!
Using a Decibel meter at 1.5m from the unit gives 50dB for the low fan setting, 55dB on medium and 60dB on high.
To put this in perspective, my office is usually about 40dB – library quietness. The unit’s low fan equates to moderate rainfall noise; medium, general open office hubbub; and high is conversation levels to get over the hubbub. I found the high setting too noisy for continued use.
When other GadgetGuy staff saw the device, they were universally interested as portable air conditioners go well with itinerant unit living.
But after testing, we all agreed that while the micro-climate was effective, we preferred a portable unit with say 10,000 BTU, despite the these requiring external venting and draining.
So, in specific circumstances CloseComfort micro-cooling works as promised. In all our tests the best we could say is that with the unit placed 1.5 metres from us we could feel a difference – micro-climate – but the rest of the room was just as hot, if not hotter because of its exhaust.
Our testers objected to the fan noise.
We joked that if you had a tent and a very long extension cord, it would be perfect. And it may be good in a Winnebago or caravan too if you can let the exit heat escape.
It creates a noticeable micro-climate at up to 1.5 metres from you – it cools a space about 1-2 cubic metres
Inbuilt water collection
It is in no way a portable room air conditioner – nor does it claim to be
GadgetGuy has a conundrum – Do you rate it as a personal cooler (which is its advertised purpose) or a portable air conditioner (which makes sense for Australia’s climate)? Answer – the former.
Overall: 3.8 – and only for the right person who has a specific need that this device fills
Features: 5 out of 5 – It does what it claims
Value for Money: 3 out of 5 – $649 compared to a 10-15,000 BTU portable unit starting at $300
Performance: 3 out of 5 – it does not meet all specified performance parameters particularly noise and heat dumped into a room
Ease of Use: 4 out of 5 – idiot proof install
Design: 4 out of 5 – reminiscent of an office water cooler crossed with the flying nun