What is this Dry Mode Control in Air Conditioner?

Those who have newer air conditioners bought in recent years will notice that there is an additional button in the remote controller.  This button is called "Dry Mode".  Some like it as they claimed it could save energy; some just ignore it completely.   This button is not available in the older models. What is this button and how does it work to provide cooling?

Why The Button?

Our body is sensitive to temperature as well as humidity. When the temperature is hot or cold, our bodies can feel it immediately. When the humidity is high or low, we might not feel it immediately but over time, our body will react to it. 

This is because 1/2 to 3/4 of our bodies are full of water. When water evaporates fast enough from our bodies, we will feel the sensation.  The feeling is just like we are under a fan.  The air blowing towards us evaporates vapor from our bodies.  The faster the airflow,  the higher the evaporation, the better will be the cooling. 

The air conditioner is also an air dehumidifier but not as efficient as a real dehumidifier.  When it cools the air,  it also removes water vapors from the air.  This is a natural cooling process. The dry mode button will instruct the air conditioner to operate more like a dehumidifier.

 

The dry mode will be particularly useful in tropical countries where humidities are usually high.  The dry mode can help to lower humidity in the room more quickly than the normal cooling mode.

 

How Does it Work?

As a simple illustration of how airconditioning and dry mode works,  if the air conditioner's airflow is strong, it is working as an air conditioner; on the other hand, if the airflow is reduced, it is working as a dehumidifier.   It appears that the airflow is forcing the air conditioner to change from air conditioning mode to dry mode. 

Slow Fan Speed Not Freeze Coil?

Of course, its controls are not so simple.  The control involves also the speed control of the compressor.  There is also a need to make sure the cooling coil will not freeze when the airflow is reduced.  This is why the dry mode button is not always available in older models that have fixed-speed compressor motors.

This is one possible control strategy:

The Best Design Strategy for Dry Mode?

Dry Mode slows down the fan speed so that the evaporator coil can condense more vapor out of the air when the air passes through the coil.  It will use some energy and be able to lower the humidity faster than usual to an acceptable and comfortable level.    

Different manufacturers have different design strategies for dry mode; some adjusted also temperature as well as the airflow in their cooling strategies. The idea is to achieve a desired comfortable cooling condition.

It has been commonly accepted by researchers that the most comfortable room cooling condition is 25^oC@ 55% humidity. This is the room condition that most manufacturers are using to design their air conditioners.  For the angle of saving more energy,  there is a tendency for the professional to pick 65% humidity level as the new comfortable humidity level.  

Anyway,  different people might have different feelings and reactions towards temperature and humidity.  For this reason,  most manufacturers will still allow users to adjust the temperature in the dry mode.  If temperature adjustment is available in dry mode,  most users will still use 25^oC as the setpoint temperature.   This does not necessarily save energy.  This is because the energy to maintain the room at the comfortable setting of 25^oC@ 55% humidity will more or less remain the same. 

Will Dry Mode Save Energy?

The dry mode lowers the fan speed allowing moisture in the air that flows through the evaporator coil to be removed more quickly.  It still consumes about the same energy to maintain the room's humidity at the desired comfort level of 55%.  However,  if one finds it comfortable to allow the room temperature to be set higher than the usual 25^oC, one will be able to save some energy.

Operating an air conditioner at econ cooling mode or auto mode will save more energy as the air conditioner is always set to run at the most efficient designed load capacity under this operating mode. Depending on the design, the airconditioner's efficiency can vary a lot at different load capacities.

Difference between Cool, Dry, and Econ Modes?

The newer air conditioner having an inverter or otherwise to control the speed of the compressor motor allows 2 additional modes of control,  namely Dry Mode and Econ Mode.  The differences between them are briefly described in this table:

Mode	Mode Description	Usage	Energy Saving
Cool Mode	Default mode	in hot and humid weather to maintain constant temperature control	Saving Depend on selected temperature;
Dry Mode	New Function	In not too hot weather or raining season to lower humidity to achieve comfort cooling	Save energy if the temperature can be allowed to be set higher.
Econ Mode	New Function	In not so hot weather to run the air conditioner at a most efficient level	Prevent excessive low-temperature cooling to lower electricity bills

How Best to Verify if an Air-conditioning Fan Coil Requires a Chemical Washing

Chemical washing of air conditioning units is always expensive.   It is a difficult decision to make for the novice especially when the air conditioner is still in good working condition after the last servicing.  Also,  chemical washing of air conditioning units can be messy involving a lot of after-service work such as floor cleaning,  etc.  This article will describe a simple and yet cost-effective way to verify if chemical washing is necessary.

How They Tell? 

The very experienced will often determine if a chemical washing is required by just visually inspecting the condition of the fan coil.  The more responsible mechanics might carry out air flow, refrigeration pressure, or cooling coil temperature measurements.  But the result of these is just "Greeks" to the Novice.  Some might like to be convinced if the expensive chemical washing work is required.  

A quick and dirty method to tell if chemical washing is required is to use backlight inspection.  This method will use a bright light shining from the back of the fan coil unit.  The Novice can easily use this method to verify if a chemical washing is required.  

What's Needed? 

All one needs is a very bright inspection lamp that can be inserted behind the coils.  This lamp must be small & thin enough to "snake" through the very narrow space around and behind the axial fan as shown. 

This brightly lighted lamp behind the cooling coils will allow one to inspect the fins.   If the fins are badly clogged with dirt,  one could hardly see the bright light emitted by the lamps.   

Where to Buy this lamp?

This lamp can be purchased from Internet Shopping.  

The alternative is to construct such a lamp using the following components from eBay:

To make these cheap eBay lamps as inspection lamps,  one might have to stiffen the lamp wiring with some sort of thin gauge stainless wire or equivalent.  

One could also construct this inspection lamp quickly using  SMD LEDs powered by AA-size batteries with steel wire as stiffener as shown in the following picture.  The number of batteries to be used will depend on the rating of the LEDs.   Usually,  3 batteries would be more than enough to power up the LED lamp.  The addition of a small copper heat sink would ensure lasting performance.   The SMD LEDs can be extracted from spoilt LED lamps.

 The Result

    

Selecting Air Conditioners

24 July 2018

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1) Update: 15 December 2021: Straight payback for Added Cost

Air conditioners are common household items nowadays in Singapore.  There are many different types and brands in the market and selecting the right type can be a headache for some,  particularly those new apartment owners. This article will help these users understand the various type and main differences between them so that they could select the correct type.

Types of Air Conditioners

Generally,  air conditioners for the resident units can be divided into window air conditioning units and split air conditioning units.   

Among the window units,  there are the window-mounted,  wall-mounted window unit, or casement window units. 

Among the split air conditioning unit,  there are single split or multi-split air conditioning units.  Then,  there is also a ceiling-mounted type which will not be covered here.

  Differences Between Window Unit or Split Unit Air Conditioning 

Detail Descriptions	Window Units	Split Units	Multi Split Units
1.  Type	The cooling and compressor or condenser units are integrated	The cooling and compressor or condenser units are separated and linked by copper pipes	It is the same as Split Units except up to 5 Indoor units can be connected to one outdoor unit
2.  Installation	Usually installed under or next to the windows,  at arm’s or lower than arm’s level.	Usually installed above the window or at the ceiling with outdoor units on a ledge or stainless steel support just outside the windows	The indoor units are connected to the outdoor unit via copper pipes through a control valve integrated with the outdoor unit
3.  Pipings	Not required	Insulated pipings are usually hidden inside PVC trunking running along the walls	Same as Split Units
4.  Power point	Required	Required with additional wiring for outdoor units running together with pipings in trunkings	Same as Split Units
5.  Noise control	Can be quite noisy	Only the outdoor unit runs a bit noisy.   Indoor units are rather quiet.	Same as Split Units
6.  Cost	About 30% cheaper than split units	Total cost would be cheaper than multi-split	Total cost would be more expensive
7.  Energy Consumption	For the same type of compressor i.e. inverter vs inverter,  cheaper to operate	Higher consumption because of piping thermal and pump head losses.  Losses in pipe around 10 watts per metre run.	Energy consumption can be high if long pipings are required;  also,  the control valve may not control refrigeration flow properly if the valves are faulty.
8.  Verdict	Cheap and efficient for the same type except the operation is noisy	Good only when one has adequate space for separate outdoor units	Can save space of the outdoor unit

 

 What to look for When Selecting  Efficiency Air Conditioner?

One of the most important factors in selecting an air conditioner is based on energy consumption or how much electricity the air conditioners will consume.  In Singapore,  it is mandatory in some countries that each air conditioner unit must have the following energy label so that the consumers can choose the right air conditioners.  Naturally,  the more the “Ticks”,  the more efficient will be the unit but for the higher the cost.  The consumers can also compare the annual energy cost which is specified in the label before they buy the right type of air conditioner. 

 Inverter vs Non-inverter

Air conditioners with "Inverter" are generally able to save more energy than the "Non-inverter air conditioners.  This is because the inverter air conditioner has load capacity controls that can control the speed of the motor to respond to the air conditioning load.  If the load is high,  the motor will run at full speed;  otherwise,  it will reduce the speed to save energy.   The non-inverter control can only start and stop the motor between high and low and low air conditioning load.  

The word "inverter"  is a jargon often used in electronic engineering to describe an electronic device that can convert AC supply to DC supply in order to control the speed of DC motors that are used in air conditioners.  There are also other kinds of energy-saving air conditioners using other kinds of technologies that might not have found footings in the market.

Basic Consideration

 1.  Whether to install split air conditioners or window unit air conditioners for energy-saving depend much on the design.   Basically,  if both air conditioning units of the same power and type (inverter vs inverter)  should consume the same amount of energy with split units consuming slightly higher power because of the heat losses through the longer refrigeration piping.  On the other hand,  if the window unit is badly designed without proper segregation between cooling and air intakes, it can consume higher energy.  Window units generally are noisier.

2.  Whether to install a multi-system or several single split systems will depend much on the air conditioning usage and the heat load of the cooling space.  Multi-system usually have control valves distributing refrigerants to various rooms; it will consume more energy in empty rooms as these control valves do not always work efficiently to cut off refrigeration flow completely especially after some years of operation.  For example,  if one installed a  system-3 to always cool only 1 bedroom most of the time,  it will not only cost more but also consume more electricity than 3 individual split units.  

Cooling Power Selection Guide 

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 Update 16 December 2021

Straight payback for Additional Cost

Newer air conditioners will be more energy efficient for reasons that there might be some innovative improvements made to the design of the air conditioners.   There might also be better material being used to improve efficiency.  If one has been using the air conditioners for quite some years,  it may be time to consider replacing the air conditioner.  Also,  if one decides which brand to use,   one should examine if it is worth the while to spend the additional sum to get a better and more energy-efficient air conditioner.

For those who are interested to find out more,   here is an example to use.   The attached table works out the cost-effectiveness between 2 popular brands using inverter technology and one other brand using conventional technology.   The table uses the power consumption and the coefficient of Performance given by the manufacturers.   One could use the table as an example to work out a similar table for other types and sizes of air conditioners.

Notes:

1.  The Coefficient of Performance (COP) is a SI unit measurement of energy efficiency used widely in many countries.  It is equivalent to the Energy Efficiency Ratio (EER) in use in the US.  COP is defined in terms of cooling power in watts per watt of electricity input and EER is in Btu/hr per watt of electricity input.  A COP of 1.0 equals EER of 3.4.    This is because  1 W is equal to 3.412 BTU/h or 1 KW is equal to 3,412 BTU/h.

For the convenience of the readers,   the attached Google sheet will help to calculate the payback of the additional cost of selecting a more efficient air conditioner which will be more expensive.  Please place selected air conditioner in column D

Reference:

1)  Mitsubishi Technical Data for MSY-GN10VA

2)  Panasonic Technical Data for CU-PS9UKZ

 

 

WuKong Air Conditioner Smart Controller

7 January 2016

tinyurl:  https://tinyurl.com/y836bbko

Introduction

Air conditioner is no longer a luxury but a household item in Today’s Singapore.  Most air conditioners nowadays have a simple controller with limited functions;  also,  these controllers are of a manual type and not intelligent.   The intelligent ones,  called smart controllers, will learn the control codes of existing air conditioners and allow users to control the air conditioner either through a set of pre-defined or customized programs or control strategies for comfort cooling as well as for energy conservation.

Types and Brands

There are several types of smart controllers available in today’s market.  The common ones are WukongI8 made in China,  Tado made in Germany and Ambi Climate made in Japan.   This article will examine only WukongI8.  

What is WukongI8?

WukongI8 is a smart air conditioning remote control that is designed and manufactured by a Chinese Company called “Gallaxy Wind”.  It is retailed at around RMB129/= for a standard model that controls only air conditioners and RMB190 for a model that will also control TVs and other devices such as lighting.  One can buy WukongI8 from TaoBao.

How WukongI8 Can Make  Air Conditioner Smarter?

WukongI8 is a smart controller.  It has a  set of independent built-in temperature and lighting sensors,  a microphone, and standard programs that can automatically turn on the air conditioner at 9:00 pm, for example,   lower the fan speed at 10:00 pm;  thereafter,  increase the room temperature by 2 degrees C in order to save energy.      

WukongI8 can also be programmed to run at other combinations with a different control strategy.  It has also a built-in energy monitoring recording device where users can use to monitor the energy usage of each control strategy and pick the right strategy.     

As WukongI8 is linked to the handphones through an internet connection,  the user can therefore program and control the air conditioner from anywhere around the Globe provided there is an internet connection.  There is no hard wiring connection between the air conditioner and WukongI8.  Connection to Router/Internet is through WiFi links.    

What are the Specifications?

Power Supply Input：85~240V AC

Power Supply Output：85~240V AC

Frequency：50/60Hz

WiFi:  WiFi2.4GHz b/g/n

Standby Power: ＜2W

Maximum Load：3500W

Maximum Current：16A –Australia/China grounded  AS3112

Andriod & iPhone software:  Andriod  2.3.7 or  iOS 7.0 and above

Official Warranty:  1 year

Firmware update:  free

What are the Basic Control Capabilities?

Besides the basic function of performing as a standard remote control,  WukongI8 can also perform the following additional functions

1. Has presets to turn on and off at air conditioner in 20-time segments
2. Automatically turns on the Air conditioner to cool room temperature to 24C when room temperature exceeded 30C.  It has also control strategies for heating functions;
3. Measures and logs the energy consumption of the air conditioner  giving aggregated yearly,  monthly, and daily energy usage
 

It has various pre-designed control strategies,  such as auto-cooling,  profile cooling,  auto sleep cooling etc;

Using the phone’s GPS system,  WukongI8 is able to tell if the user is carrying out the control at home or outstations and choose the desired control program.

What is the type of air conditioners that can use WukongI8?

 

WukongI8 can only work with air conditioners that have an infra-red remote controller having an LCD screen.  WukongI8 cannot work with radio frequency, remote controllers.  

How to Install? 

 

Installation is simple and straightforward.  Just plug in WukongI8 in series with air conditioner if one's air conditioner is connected to a  powerpoint nearby.   

However,  most split air conditioners in Singapore are remotely connected to a 15A socket outlet and therefore,  one would have the following two options:

1.    Extend the power to connect WukongI8 and locate WukongI8 within 5 meters from the fan coil unit;

2.    Rewire the power to the air conditioner so that the power to the air conditioner can be drawn from WukongI8’s 16A power socket. 

Note: As Wukong uses Chinese 16A power socket format,  one would have to use proper 16A socket outlets which can be ordered from Taobao 

As infra-red communication will need the transmitters and receivers to be able to “see” each other,  it is, therefore, a requirement for WukongI8 to be installed directly opposite the air conditioner.  However,  WukongI8 could also work to a distance of 6 meters at an acute angle of not more than 50 degrees.  

Can I install Wukong Separately?

 

Wukong can work separately without the air conditioner’s power  drawing from Wukong’s 16 A power socket but it will not be able to record and monitor the power usage

What will happen on the Connection of Wukong?

Once WukongI8 is physically connected up to a power supply,  it will scan the room for an air conditioner to learn the control codes and connect WukongI8 automatically to the air conditioner through the infra-red transmitter/receiver.  Upon successful connection,  the blue light of WukongI8 will turn on;  otherwise,  the lights will turn red,  indicating the loss of signal connection. 

The original remote controller of the air conditioner will still work and will override and bypass the controls of Wukong. 

How Do I Control Wukong?  

To control Wukong,  the user must 

1.    Download the handphone Apps,  called Wukong Home from Google Playstore.  https://play.google.com/store/apps/details?id=com.gwcd.airplugor download and register Weixin first as a user and then  use its QR code reader to scan the code on WukongI8

2.    On the first successful download,  the handphone will search for the presence of WukongI8 and retrieve its Ids for a user to set up the Apps  with a password; after that

3.    WukongI8 will scan the room for a compatible device,  learn the infra-red control code, and connect to the air conditioner'scontrol

4.      Once the connection is successful,  a familiar screen will appear and one can use the handphone to control the various basic functions of the air conditioner

From this page,  one can navigate to set the basics parameters such as languages,  Centigrade/Fahrenheit, and other parameters

  

On other pages,  one could manually check and control the various functions of the air conditioner such as temperature,  fan speeds & swings,  timer etc

On selection of the Smart Mode,  one would be presented with various control strategies to control the workings of the air conditioner as shown,  from constant cooling to temperature profile cooling,  night cooling,  auto cooling, etc.  By selecting the "details",   Wukong will give a description of the strategy.   

Wukong also provides a graphical plot for temperatures of the room for the last 24 hours

The Useful Functions

1.  Temperature Curve

This will allow users to set the hourly temperatures with a preset range so that one could have a lower temperature before sleep for example and then turn up the temperature in the middle of the night etc.  This temperature curve setting will be over-ride when the original air conditioner's controller is used.

 2.  Auto-Sleep Function

This function will lower the fan speed and also lower the set temperature by 2 C if the room temperature is above 28 C. 

What is  Inside WukongI8?

1.  Opening up WukongI8

1. Remove the front panel which is held onto the casing by glue
2. One will expose the components such as infra-red receiver,  temperature and lighting sensors and also the microphone

3. The controlling  unit can then be removed as shown

4. The controlling unit consists of the following components attached in the back of the unit

a)      The power supply unit

b)      The WiFi Board  and the EEPROM

c)      The Main Control Board

d)     The Power Output connection

Performance and Energy Savings

It is hard to compare the performance with and without Wukong operating as we have also bed cooler in operation at the same time.  

An energy data acquisition instrument was used to measure the consumption of the air conditioner together with the bed cooler over a period of 1 month for various combinations.  They drew about 2.5 KW  to about 5 KW depending on the setting of the Wukong.  Generally,  the various measurements can be divided into 5 categories

1. Power cooling for 3 hrs @ 26C without Bed Cooler and Wukong
2. Wukong Auto Sleep Mode without Bed Cooler
3. Wukong Auto Sleep Mode with Bed Cooler
4. Power Cooling for 3 hours @ 27C with Bed cooler but without Wukong
5. Wukong Temperature Curve with temperature setting between 26 to 28C with bed cooler

Note:  Power Cooling is a feature of Panasonic air conditioner which lowers the room temperature setting by 2C with higher fan speed

It has been found that Wukong has helped to save about 26% of the energy consumption.   With bed cooler and Wukong working in combination,  a further 13% energy could be saved with comfort cooling for a good night's sleep.

Note: The bed cooler was set to 29C which required the air conditioner to operate at lower than normal temperature and therefore,  consumes more energy.  More energy could be saved by setting bed cooler at temperatures lower than 29C.

 Conclusion

It is expected that more such devices will flood the market in the future as more people learned how to use the smart controller.  It is also expected that pretty soon,  the smart controlling device will become a standard item in the new air conditioners. 

Appendix I:  Suggestions to Improve Wukong

1. Temperature Curve to be set according to startup hours instead of the hourly clock

Presently,  the curve is set to the hourly clock.  The air conditioner will start at preset hour irrespective if one needs the air conditioning.  This leads to unnecessary wastage of energy.  For example,  if one were to preset 28C at 11:00 pm,  one would have to re-adjust the setting to the desired temperature when one starts the air conditioner at 11:00 pm.  A refinement would be to allow the temperature curve to be set according to when the air conditioner is turned on.  

2.  To prevent the Temperature Curve to be turned on automatically,  one would have to turn off the temperature curve setting every day and then turn the air conditioner from there;  otherwise, Wukong will not work properly.

  

Appendix II :  FAQ

1.  Can we use WukongI8 in an old air conditioner?

So long as the remote control is of the infra-red type that has temperature,  fans and other controls.  If the air conditioner can use universal remote control,  most likely there will be no problem.

2、Can I use it for Package unit air conditioner?

            Not supported

3、Can WukongI8 control other appliances?

Not supported

4、Can the APPs be shared among family members?

Yes

5、We don’t have WiFi at home

WukongI8 must work with WIFI router

6、What’s the  Wifi Speed?

2.4Ghz。

7、Any distance limitations?

Not for the handphone’s WIFI control as it uses the internet which can even control from overseas;  however,  WukongI8 must be installed as close as possible to the air conditioner.  Rightly speaking,  the infrared sensors of the air conditioner and WukongI8 should  "see" one another;  however,  depending on the color of the walls and ceiling,  the author has tried that one can still have adequate control receptions up to 6 meters at an acute angle of not more than 50 degree.

8、What is different between Weixin and the standard model?

The standard model does not have the Weixin function but the WukongI8  home App is useable for both models。

9、What is the handphone requirements?

Andriod 2.3.7or iOS 7.0 and above

10、Where can I download the WukongI8 Apps？

Use Weixin to scan the QR code on the box or unit or download directly from Google playstore. 

11、Why socket-outlet is 16A？

That is the standard outlet rating for air conditioners in China. Singapore uses 15A.

12、Ease to install？

As described in the blog。

13     We use a Universal remote controller？

Should be compatible with WukongI8. 

14、Can we still use the normal remote control?

Yes.

15、If I lost the password for WukongI8 home？

Reinstall WukongI8 with a new password。

16、What capacity air conditioner？

3 horsepower (HP) or less or not drawing more than 3500W.

17、What if our remote control is not working?

Try Universal remote control.  If it is still not working,  most likely the air conditioner remote control is faulty

180、Does WukongI8 works with other remote controllers?

It will not work with radio remote controllers.  Most likely, this controller will have no LCD screen. 

tinyrul :  https://tinyurl.com/y836bbko