Are Bladeless Fans a Scam?

this is a bladeless fan it blows fast moving air through these little slits around the oval whenever a fluid moves fast it has a lower pressure so this lower pressure sucks in air around the room the bladeless fan companies like Dyson call this air multiplication you can see if I put some smoke on the back that it does indeed suck air through this big hole in the middle so we end up with more air being blown than we started with you can see this even more clearly if you take a big bag like this and then ask someone to blow it up now they might do something like this and just start taking some breaths and blowing it in the bag you can see this is going to take a while to blow up the whole bag but you can actually do it with just one breath all you have to do is go like this it blows it up instantly so the moving air was able to drag in air from around the room and fill up the bag really fast this happens because the moving air creates low pressure that sucks in air from around the room into the stream but the weird thing about this is you don't magically get more energy just by moving it away from your mouth both breathing close to the bag and away from the bag took about the same amount of energy blowing so in terms of an energy balance we have enough energy to blow up the bag in one breath but we didn't have enough air so to get more air we used fast moving air to suck in slower moving air from around the room and that amount of slow moving air can fill up the bag so this experiment might lead you to believe that these bladeless fans might be super efficient way more efficient than a normal fan in fact if you just do a quick Google search about bladeless fans you'll see that all the sources say that they're quieter and more efficient than regular fans but is this really the case well today I'm going to be testing out a bladeless fan and a normal fan to see if the bladeless fan really uses less power than a regular fan now one thing we have to understand about bladeless fans first is they're not really blad less they actually do have fan blades but they're just hidden in the base here and these fan blades are what's sucking air and air through the bottom and pushing it around these gaps here we're going to test how much wind speed is created at the same power consumption for both of these types of fans now in order to test this I have a wattmeter and an anemometer an anemometer is just a device that measures wind speed so it turns this little blade in here and depending on the rate that that really frictionless blade in there is turning it knows the wind speed that's blowing through it okay so let's plug in our bladeless fan okay both of them are going to be 33 in away from the edge here okay it's on the highest setting now and we are using 4.9 Watts so we're just going to call it 5 Watts that this is using right now at the high speed okay it's up here for some reason so I'm at 1.6 m per second I think that's the highest value okay so here's a view where you can see it a little better we're at 1.4 m/s up here and we're using 5 Watts back there right here 4.9 now we're going to test our desktop fan so with this one I'm going it only has three speeds so to try to match the 5 Watts I'm going to use this variac here so I can change the voltage so basically I can control the speed of the fan at any speed it continuously so just by turning this I can change the speed of it this one can get really high but we're going to turn it down oh it's using a lot of power so we're at even at this low speed we're at 19 Watts so don't know if this is going to work if I turn it down which is 6 Watts the blades are barely even moving so I can only get it to turn at like 8 watts and that's like barely even moving any air so this fan is definitely not the fan to use for this so these are meant to run at high voltage high power to Output a lot of air so this isn't a good comparison to the smaller fan that uses way less power instead I'm going to be using this fan this is actually probably a better comparison cuz this is a DC motor just like the bladeless fan was also a DC motor okay let's turn it on okay so on the bottom here it's showing the Watts used okay so we're at 4.9 Watts let's see how much air this generates okay so I'm at 1.8 m/s and also it's easy to tell this is a lot bigger area that I'm picking up wind speed so I can pick it up over here all the way you can see the blade spinning here you can see how I get this full breadth of area here it's like this big that it's blowing the air so we've got four 4.8 4.9 watts in the back and we're 1.8 m/s down here so you can see we're getting the same as or faster air speed with a regular fan compared to the bladeless fan in fact we're moving a lot more air so there's a lot more air flow at a higher speed with just the regular fan but as you can see with just different types of fans and different Motors there's all sorts of different efficiencies so I think a better comparison would be to use the exact same fan in both cases so I'm going to take the fan out of the base of the bladeless fan and see if it's more efficient when it's outside of the base than when it's inside of the base blowing through those tiny slits okay so here's the fan in the base so it should blow out the front here so it's just blowing out here and in the fan they have it directed up through these slits so now let's see how much air blows if I don't put it through the bladeless portion meaning I'm not directing it through these tiny slits now the motor is completely out of it going to turn it on okay we're at 5 Watts let's see what our Max wind speed is now okay well look at that we're getting up to two so 2.1 but if I just put it back in the base but then when I put the slits back on it's only at 1.4 using the same amount of watts in the end we actually lost efficiency when we put this base over it and made it have to come out these slits and when you think about it it makes sense because you're sucking in Era here anyways why do you have to try to suck in air through the back here what good does that do you you might as well just not restrict the f fan at all take this off and just let it blow so the reason that the bladeless fan doesn't outperform a normal fan is because a normal fan also entrains air on the side so both a regular fan and a bladeless fan pull in air from the side but the bladeless fan also pulls in air through the center but because it has pulled in air in the center that fast moving air that's coming out of the slits gets slowed down because it's hitting air that's coming in through the center that's not moving fast so overall the overall air speed slows down now maybe these could be more beneficial with a specific type of fan that you can put in the center that you couldn't use outside of it so there could be some benefits that way but in the experiment I just did I really don't see any benefit to a bladeless fan now one thing people really like is that bladeless fans are usually quiet but you can see that that's just because the power consumption is much lower and the amount of air it moves is much lower than just a normal traditional cheap fan but if you compare the amount of wind moved per energy used the blade fan doesn't beat out a traditional fan now this fan was like $50 to buy some of the expensive Dyson ones can get up to like $ 6700 and I don't see why that would be more beneficial than just having a regular fan but I did forget to mention one of the main reasons why people buy a bladeless fan hey Joanna check out my new fan why it's bladeless oh you seem way cooler now and thanks for watching another episode of the action lab I hope you liked it if you haven't subscribed yet remember to hit that subscribe button and we'll see you next time

Channel: The Action Lab

Views: 788,540

Keywords: bladeless fan, the acion lab, dyson, efficiency

Id: ySSo5PmZZJM

Length: 8min 47sec (527 seconds)

Published: Sat Oct 28 2023