Mitsubishi to Release Air Conditioners with Human Location Sensing Capability

Nov 7, 2006
Motonobu Kawai, Nikkei Electronics & Chikara Nakayama, Nikkei Monozukuri
Mitsubishi's air conditioner able to sense human location
Mitsubishi's air conditioner able to sense human location
[Click to enlarge image]
Infrared sensor unit. It screens the room horizontally and measures temperature distribution by dividing the whole room into 500 areas.
Infrared sensor unit. It screens the room horizontally and measures temperature distribution by dividing the whole room into 500 areas.
[Click to enlarge image]

From mid December 2006, Mitsubishi Electric Corp. will launch seven models in series from its "ZW series" air conditioner lineup for home use. The series enhanced energy saving efficiency and user's comfort based on a system that controls air conditioning in light of human location in the room. The company introduced its first "Kirigamine" air conditioner product in 1967. As "products integrating 40 years' history of our Kirigamine" (Mitsubishi), the new lineup features auto cleaning capability for filters and outlet fans and compact size with the width of an indoor unit reduced to less than 800 mm.

The air conditioners detect human location with an infrared sensor unit called "Human Sensor Move Eye." This unit is attached downward in the middle of an indoor unit's bottom face and automatically moves between left and right. It takes about one minute for the sensor unit to go back and forth between a range of 160 degrees wide. Through this move, the sensor unit measures temperature of the room's floor and wall.

The company's previous products also featured similar sensors to measure temperature of the floor, but they only could analyze the room's temperature distribution by a total of six areas using two infrared sensors, each of which watches over three areas.

With the new Human Sensor Move Eye system, a row of seven infrared sensors scans inside the room and each sensor acquires temperature data by dividing its coverage area into 66 segments. In other words, the system can acquire temperature data from about 500 segments.

Given the capability to divide the room into small pieces and measure temperature in detail, the new system can precisely sense the size and move of heat sources. "The unit recognizes a human with its high temperature as well as its move of more than 30 cm" (Mitsubishi). Therefore, the sensor does not consider kitchen and other fixed heat sources as humans. However, Mitsubishi said the sensor can maintain its recognition of a human as long as its temperature remains high, even if the object stops moving after being sensed.

In this manner, the new air conditioners locate humans, centralize the area of air conditioning to the location of a man and automatically switch to economic mode when no one is sensed inside the room, for example. The system can save up to 50% of power, combining 10% by integrating air conditioning area to the human location and 10% by switching to economic mode when nobody is in the room, along with existing energy saving effect (about 30%) by weakening air conditioning in line with floor temperature.

The lineup can cope with the situation where there are two people at a time inside the room by moving each of upper, lower, left and right flaps at its air outlet using four separate motors. On the other hand, the lineup can also control air not to directly hit people in the room. It also features a capability to analyze trends of human location in each family, based on results of its survey for about half a month. The current model only controls the direction of air when starting operation based on past data saved by the company. Mitsubishi intends to "further boost the precision of human location sensing in the future, using data we have accumulated."