Small Portable Air Conditioner

These days, lots of people are searching for small portable air conditioners and coolers. That’s not surprising with our warming climate.

It’s hard to choose because there are so many deceptive small water cooler web pages cleverly marketed so you find them when you search for something like ‘mini portable air conditioner’. A hot summer turns desperate clicks into rivers of gold.

The just try searching for ‘small air conditioner’. Many of the results will feature something like this desktop water cooler with prices up to $200. You might be surprised to find you can buy one in your local hardware store for $5, which is an accurate indication of their real value.

Small water coolers that pretend to be mini portable air conditioners

This is a simple machine. A small fan drives air past a wet screen. If the air is dry, evaporating water cools the air. If the air is humid, there is much less cooling. A small water tank provides enough for a couple of hours. Most run with a USB charger and more expensive models come with rechargeable batteries.

In dry air will provide 3 – 5 degrees of apparent cooling if you can place one nearby on the desk inches away with the air flow aimed at your face. The cooling effect will be around 50-100 times less than what’s needed to cool even a small room, so don’t expect much.

After several weeks, you will need to replace the wet screen or it will become infested with mould and smelly.

They can be useful inside an air conditioned building if you find yourself in a localised hot spot, maybe with warm afternoon sun. Wherever you see prices above $25 with slick advertising, know that your hard-earned money will be paying advertisers, not providing you with a valuable product.

Unfortunately some of the advertisements appear to be internet scams. At our company we have received calls from customers wanting their money back because they did not receive anything after paying with their credit cards.

Large evaporative “swamp cooler” ( 100 – 120 cm, 40 – 50 in height )

Large water coolers

There are many excellent water coolers that can work well in dry climates like Albuquerque (NM) or Pheonix (AZ) provided you have a good supply of clean water. They are large machines and need lots of water. The tank has to be refilled every few hours. Most are rather noisy because the fan moves a lot of air past the internal wet screen. Furthermore, you will need to replace the screens regularly to avoid smells.

These machines will provide cool air for a large room or even several rooms.

Apart from the size, ugly appearance, the need to keep refilling with water and replacing the screens, they increase the humidity inside the building. Falling temperatures at night raise the relative humidity to the point where it can seem hot, damp and uncomfortable.

Even moderate humidity (>35%) greatly reduces the cooling that these machines deliver. Above 50% relative humidity, only slight cooling will be possible.

Coolzy – The small portable air conditioner

Coolzy is a small portable air conditioner, or personal air conditioner. Inside you will find the same parts as in a traditional room air conditioner. Coolzy is just like a tiny refrigerator with a fan that blows cool air at one or more people nearby.

A compressor pushes refrigerant gas into a condenser heat exchanger where a fan blows air through the fins to cool the refrigerant gas so it condenses to a liquid. The liquid, still at high pressure, passes through a thin capillary tube or an expansion valve, reducing the pressure. The low liquid is squirted into a second heat exchanger called the evaporator. Here the liquid evaporates into a cold gas, cooling air flowing past the tubes. The gas, now warmer, passes back to the compressor where it is compressed once again.

Traditional portable air conditioners use lots of electricity to pump heat outside, typically 1,200 to 2,400 Watts. Unlike the Peltier coolers, they do pump lots of heat. The CoP for machines with two pipes is usually between 2.3 and 3. One brings outside air to the machine and the other takes hot air back outside.

Portable air conditioners with only one pipe seem at first to be simpler and more convenient. However, they perform far worse than other room air conditioners because they suck in cooler air from the room to absorb the heat and pump that air outside. Air has to come in from the outside to make up for the air pumped out, bringing heat and humidity with it. Therefore, the net cooling effect is halved so the CoP is only around 1.3 – 1.6. That means you need two to three times as much electricity compared with a split or wall-mounted air conditioner to achieve a similar degree of room cooling. Don’t expect more than 3-4 degrees of room cooling.

Unlike other air conditioners, Coolzy does not mix the cool air with the room air. Instead the cool air is carefully focused at the user’s face and upper body, just where we are most sensitive. Therefore, a very small amount of cooling is much more effective at creating the sensation of comfort. Coolzy sends warm air from the back to the ceiling, just like a kitchen refrigerator or freezer. Coolzy provides around 20 times the cooling power of the small evaporative coolers we mentioned above.

Coolzy is as close as we can get to the ideal mini air con, a really small portable air conditioner that provides comfort with very little electricity.

So how does this mini AC compare with the myriad of other cooling solutions now available online?

The traditional mini-split AC is great for cooling a crowd. It cools the whole room by thoroughly mixing the cool air. Most of the energy, of course, cools bricks, concrete, steel and timber. Everyone in the room will experience air with a similar temperature. The air conditioner also removes excess moisture, through this can lead to dryness, skin, nose, throat and eye irritations after many hours. There are three big disadvantages:

  1. A mini-split does not change the air in the room, so air quality decreases as carbon dioxide, volatile organic compounds seeping from furnishings, and body odours all accumulate with time. Opening a door or window provides some fresh air, but significantly increases the power required by the air conditioner for the same cooling.
  2. Because it has to be installed in the wall or ceiling, you need a mini-split in every room where you may need cooling. That’s expensive.
  3. You need to be prepared for large electric bills. Expect to spend much more on electricity than the purchase and installation cost over the lifetime of the air conditioner.

So, if you can afford it, the best combination is to use a Coolzy mini air conditioner and install a mini-split in your entertainment room to cool your crowd of friends when you need to.