H YANKA Personal Air Cooler, USB Evaporative Coolers with Waterbox，Portable Table Fan，Ultra-Quiet Table Fan，3 Fan Speed，USB Charging，Fresh Design，Prevent of Water Leakage

The media could not be loaded.  To preface this review, I'm a licensed mechanical engineer, so hopefully this gives me some credibility on my 5 star rating. This product is a perfect solution as a personal cooler for a cubicle or small space and does exactly what it advertises and operates exactly how an evaporative cooler is supposed to work.I have a hygrometer (moisture sensor) and temperature sensor in my office and it gets relatively hot (see attached images). With the evaporative cooler, the temperature has dropped 10 F and increased the relative humidity by 5%. It is dry in my office in the winter, understandably so, and so the evaporative effect is noticeable. The device is simple - it draws in dry, hot air, and blows it over a wet medium, in this case highly absorbent sponges with lots of surface area for the evaporative effect to take place.I laugh at the one star reviews that state such laughable and unfortunate statements such as one reviewer who couldn’t cool their car with this device – it’s USB powered but I don’t think that’s the application, or the reviewer who stated that they "usually would not leave a negative review but this is just a fan that blows on wet sponges." - Um, well yeah, that's exactly how an evaporative cooler works. To get into the thermodynamics of it, an evaporative cooler takes advantage of the latent heat of fusion, or the change in enthalpy resulting from providing or removing energy by changing the state of a substance (in this case water to vapor) at a constant pressure.It takes energy to change phase and when non-saturated air, or dry air that does not contain water vapor comes in contact with liquid moisture, in this case the soaked, saturated sponge medium, the liquid in the sponge changes phase as evaporation occurs. The moisture content of the air is increased and the air is cooled - it has a constant wet bulb temperature, but the dry bulb decreases as a result of the direct evaporative cooling process until the air is completely saturated. Look up a psychometric chart if you're interested in learning more.Further, the tank above the sponge medium is also extremely helpful in increasing the humidity ratio of the air and increasing the evaporative effect and technically lower the wet bulb temperature by introducing a fine mist (see the attached photo and mini video I took of the mist). It is introduced into the air stream, I believe, by a pressure differential when the fan is operating, by the way. There is a V shaped piece of plastic in front of the fan which blocks the nozzle from the air stream creating a high pressure zone that travels around the nozzle thus creating a low pressure zone at the nozzle itself drawing in the moisture into the air stream as a mist. Pretty smart design. That said, the tank can stay full overnight if you turn it off it's not going to drip or spill everywhere.Lastly, you can also add ice in the tank to lower the temperature of the supply mist and even freeze the whole sponge filter after you soak it to help the device act as a dry cooler in conditions where it may be humid in the summer and the evaporation effect won't be as significant because of the moisture already present in the air. As the fan blows air over the frozen sponges, the warm air obviously reduces in dry bulb temperature and the mist lowers the wet bulb temperature until the frozen water in the sponge medium melts and the direct evaporative effect takes over.All that said, you can buy the same type of item on Amazon for $50-$100 or more. This is so silly cheap and does exactly what it's supposed to do it's a steal. Plus the outlet fits perfectly below my computer monitors at work and I can orient the vent to point wherever I need. Sure, the fan is a little loud even on its lowest setting and it but, as a consolation prize, for some reason there is a color changing night light which turns on every time you turn on the device and cycles from hue to hue and shade to shade to set the ambiance. Granted, I just turn it off because I'm using this at work and can't be distracted by the subtle mood lighting. The fan set to its lowest setting it is perfect for my needs but there are three fan speeds which may be useful at some point, but you may risk your neighboring colleagues starting to think you are mining bit coin because the fan speeds can start to sound like loud server fans.I hope this review helps. A few additional recommendations - To close the vent flush you have to press from the bottom of the drawer mechanism and fidget with the top or there could be a small alignment issue. Check out the images and short video I took to get a better understanding of how this works and if you're more interested, go learn how to use a psychometric chart and learn about the latent heat of fusion and you'll better understand that this is infinitely better of a device than a simple desk fan. I saw the low reviews and felt I needed to give this little device some much needed support because it's nicely engineered and well worth the price. Also, I recommend taking off the logo sticker and use some goo-be-gone stuff to get rid of it, because who likes labels?Overall, excellent product.

Much better and stronger fan than others I've previously bought. Be careful cause if you move it too much water drips out. Not a concern for me but if you keep it around any laptops or other electronics be cautious when moving it. Other than that, good product.

It's a life changer for my fiance at her job. The heat from all the office pc's and people builds up and the office A/C can't keep up. She loves it and others took notice of it quickly! It's a winner.

This Evaporative Air Cooler, Compact in size 14.5x16x17cm (5.5"x6.5"x6.5"), easy to use of 3 speed and 2 level LED changing Night Light. 5Volts dc cell phone power, just good for my personal cooler anywhere.

Not meant for big spaces. Works good for a cubicle. I would buy for filters

What a novel idea. I truly kept me nice and cool I was very impress with the product.

Works well for personal use like right next to you. Does not cool even a very small room.

This is the second machine I've boughten and both do the same thing. The sprayer doesn't and I clean it and it never seems to do the job and it just sits there.