Life Hacks in Japan

This is a blog that provides information on good buys, health, money, and other things that enrich your life, as well as your hobbies and interests! (Tap twice to view categories such as "Shopping" in the ↓.)

"Life in Japan 2023" How to choose a circulator and recommended manufacturers!

Circulators look simple but vary widely in price, ranging from about 5,000 yen to nearly 30,000 yen. The more expensive, the more sophisticated? Can it be used with a fan? Let's sort out the main points and buy a circulator that suits you best!

Before I get down to business, I will address two questions.

As you all know, circulators are typical of appliances that are highly commoditized and difficult to differentiate in performance. The wind is not proportional to the price, nor is it quieter.

I searched for relevant papers, and indeed there were reports of experiments that showed that the way the blades were grooved changed the amount of airflow delivered in front per revolution.

In terms of efficiency in a specific area, a 32% increase in efficiency was achieved with F3:1, in which a 2 mm wide x 0.7 mm deep groove was dug on the surface so that the ratio of the distance from the front to the back was 1 : 3. A 21% increase in efficiency was achieved with B3:1, in which a groove 2 mm wide × 0.7 mm deep was dug on the back surface so that the ratio of the distance from the front to the back was 3 : 1.
Increased efficiency of fan propellers - Simple surface treatment to change the wind

 

However, it would save money to buy an ordinary circulator rather than to spend tens of thousands of yen to buy a circulator with wings developed by the latest research for such slight efficiency.

Question 2: Will there be a difference in blade noise?

In the paper "Noise Reduction of Propeller Fans for Air Conditioning," the construction of the blades to reduce noise was shown, but even so, it only changed by 4 dB. In other words, we believe that the noise level is mainly proportional to the air volume, and that it is impossible for only a particular manufacturer's circulator to be quieter at higher wind speeds.

The following results were obtained from a study of noise reduction of a forward-tilting type propeller fan for air conditioning.
(1)A noise reduction of 3 dB(A) was achieved by radially distributing the airfoil shape around the boss of the fan. The improvement in flow due to the airfoil shape is the reduction of leading edge separation and the equalization of radial blade load due to the reduction of separation near the boss.
(2)The bellmouth shape has a significant effect on the aerodynamic and noise characteristics of a fan, and the shape can control fan performance to some extent.(1)A reduction of 4dB(A) was achieved by combining the two impellers in the same order.
Noise reduction of propeller fans for air conditioning

 

 

Some media outlets have stated that "the noise level varies from manufacturer to manufacturer." However, if there is a difference of much more than 4 dB in the measured results despite the same air volume, even for a jet aircraft, but with a weak output as weak as a circulator, we believe that the measurement locations are not standardized or that there is some consideration for a particular manufacturer.

Based on the above, we do not believe that there is a difference in the magnitude of noise from one manufacturer to another, even though there may be a difference in the magnitude of noise from different airflow rates.

motor

Here is the main issue.

First, let's look at motors. The characteristics of motors are as follows. Note that AC motors used to have a longer life, but since the brushless DC motors were created, the life has become about the same.

  DC motor AC motor
Advantages ・energy conservation
・Fine airflow adjustment.
・Low price
demerit ・High price ・High power consumption
・No fine adjustment of air volume

 

However, as you can see from a search on 価格.com and other sites, there are large price differences due to other features, branding, and availability, so not all AC motors come up first, even if they are listed in order of cheapest to cheapest.

To begin with, I believe that there should be only three types of air volume: low, medium, and high, and if there are more types, it is rather inconvenient because the number of operations when switching between them increases. Therefore, in this blog, I will only introduce those with three levels of air volume.

As for the difference in electricity costs, the power consumption of the circulator itself is originally small, and even if we assume that a DC motor circulator consumes 25W and an AC motor circulator 35W, the difference is only about 6 yen if the circulator is left on for 24 hours. When buying a circulator, be aware of the balance between the price of the unit and the cost of electricity.

Shape of wings

This is where the structural difference between a circulator and an electric fan comes into play. While a circulator blows air narrowly and far, an electric fan blows air over a wider and closer area. Thus, because of their opposite characteristics, fans and circulators cannot be used together.

f:id:enjoy-efficient-life:20220319081332j:plain
Brushless DC Motor for Electric Fan + Fan Unit | Nidec Corporation

 

 

Number of blades

Generally, the 3-blade type is quieter than the 5-blade type, but the 5-blade type is noisier. For the same motor output, the 3-blade type produces a strong breeze, while the 5-blade type produces a soft breeze. Unlike a fan, it is not directed in the direction of people, so we recommend a quiet and strong 3-blade type.
About 5-blade and 7-blade Fans - Ceiling Fans - Panasonic

Incidentally, fans with 5 to 7 blades are generally sold in the market. On the other hand, fans for industrial use, which are designed for use in large areas, are usually 3 to 4 blades with strong wind. (The image shows an industrial fan.)

f:id:enjoy-efficient-life:20220319075354p:plain
NAKATOMI Corporation | Factory Fan

 

Blade size

In terms of width, they range from 25 ~ 35 cm, but they vary from manufacturer to manufacturer.

air volume

Airflow is calculated by "area passed through × air velocity" and is expressed in m3/min. Some manufacturers disclose this information, but not many. If not, the air velocity will not be published more, so use the area, i.e., the size of the wings, as a guide. Some manufacturers publish the number of tatami mats as a guide.

shaking of head

Finally, we will discuss effective usage. Recently, circulators that swing like a fan are also available. Many people make the sensible decision, "Wouldn't a circulator that swings its head from side to side be better for circulating air?" Many people may make a judgment based on their senses. However, according to Professor Shinichiro Ito of Kogakuin University's Faculty of Engineering, when a circulator is swiveled, the wind is dispersed and does not flow enough to circulate the entire room. He said that a fixed curvature would result in a more uniform temperature in the room.


How can I use air conditioning to make my sleepless nights more comfortable?

 

The placement is the same for heating as well as cooling: turn the circulator slightly upward toward the ceiling and do not swing it around. Certainly the warmed air will go to the top, but by directing the air flow diagonally down the room to the ceiling, the warm air that is lodged above can be pushed downward. As a result, the entire room becomes warmer.


How can I use air conditioning to make my sleepless nights more comfortable?

 

 

Other Functions

We will omit temperature sensors and motion sensors because we consider them to be of little importance in this blog. As for the sensor, if the sensor turns on as soon as you turn on the power, you have to turn off the sensor every time you want to reduce the wind power when it is hot or increase the wind power when there is no one around, etc. A "circulator without sensor" that does not change the wind power on its own is more It would be more helpful to have a circulator without a sensor that doesn't change the wind power on its own.

Product Comparison Chart

Therefore, in this blog, we would like to focus on the following circulators for comparison.

  • Three levels of airflow adjustment
  • triploid
  • No automatic swivel
  • Low profile products
  • Less than 10,000 yen

You can scroll to the right.

Manufacturer Iris Oyama Iris Oyama Modern Deco Twinbird technos
model number PCF-MKM15N PCF-MKM18N Stand Circulator KJ-4781W SAK-23
motor AC motor AC motor AC motor AC motor AC motor
air volume     11m3 / min    
Applicable number of tatami mats 8 14      
air volume control 3 levels 3 levels 3 levels 3 levels 3 levels
3-step vertical angle adjustment 360° 360° 0 ~ 90° (4 levels) 0 ~ 90° (5 levels) Unknown (can be adjusted)
Dimensions W 252 x D 184 x H 256mm W 278 x D 214 x H 293mm W 275 × D 184 × H 315mm W 280 × D 160 × H 280mm W 298 × D 176 × H 308mm
weight 1.1 kg 1.5 kg 1.6 kg 1.7 kg 1.8 kg
Power consumption 28W(50Hz), 27W(60Hz) 33W(50Hz), 28W(60Hz) 32W(50Hz), 30W(60Hz) 36W(50Hz), 34W(60Hz) 30W(50Hz), 30W(60Hz)
price 2,233 yen 2,780 yen 4,999 yen 2,980 yen 3,351 yen

*1...Prices on Amazon as of April 8, 2023.

 

Commoditization has made it difficult to differentiate between manufacturers, but in terms of functionality, while other manufacturers only offer 0 ~ 90° gradual angle adjustment, Iris Oyama offers 360° free adjustment. In addition, it is the lightest and cheapest, so we recommend it.

As a result, I think you can definitely choose PCF-MKM15N for 8 tatami mats or PCF-MKM18N for 14 tatami mats, depending on the size of the room. if you want the one with the strongest wind, Technos SAK-23 may have the highest air volume because its main unit is the largest.

I hope the above is helpful.

For 8-mat PCF-MKM15N
For 14-mat PCF-MKM18N
SAK-23