classroom a/c wasted energy

Most classrooms have a split-type air conditioner, and the students may operate it indiscrimately. How does one reduce wasted energy?

  • The a/c is turned on at will, but left on even after using.
  • The thermostat setting is too low, resulting in much wasted energy.
  • The lights and the air conditioning are often left on even when one is around.
classroom energy management

Large schools have lots of classrooms, which means that there are a whole lot of lights and air conditioning, these are often used arbitrarily, but often left on even after the occupants leave, this is the crux of the energy wasted problem.

Traditional Approach

Scheduled Control

scheduled central control for each classroom
Shortcomings with the traditional approach
  1. Setting up the system is costly, maintenance cost is high, getting a return on investment is not easy, getting the engineering budget is even harder.
  2. Since there are many different types of air conditioners, maintenance is a problem.
  3. There are many factors surrounding the central control system, as a result the stability is poor, especially with regards to the automatic control aspect, there is great stress when maintenance time comes.
  4. There is the difficulty of integrating the scheduled control system with the information system, it is inconvenient to the instructor when they need to temporarily change the reschedule.
  5. When there is a interim change in the class and there is no one in the classroom, the air conditioner is still on.

(1) Smart Card Control

Insert card, get power; Remove card, power off

Having the instructor insert the card is the most effective form of access control.

The instructor carries the card with them. They insert the card to get power, and remove the card to cut off power.

Time based card reader:

  1. During class: A valid smart card needs to be inserted before power to the lighting and air conditioning can be obtained.
  2. After class: The card is removed and all power is cut off.

(2) Energy Saving Switch

With a K24, auto off when no one is around

Can be used by anyone, saves energy through the manual on, auto off method.

In the classroom: The K24 energy saving switch is installed
  1. Manual on.
  2. Manual off.
  3. If no one is around, then auto off.
K24 can be used for manual on/off, but also auto off
  1. Lights on during class: The lights must be manually turned on from the wall switch, otherwise the lights will never turn on.
  2. When leaving after class:The switch can be pressed to the lights off manually, but if the last person leaves and forgets, the K24 will still turn the lights off automatically after 10 minutes after detecting that no one is around.

(3) K25 Fixed Time Switch

K25 lighting and fan control
  • Upon entering the classroom, the lights need to be turned on manually.
  • On leaving the classroom, the lights can be turned off manually.
  • Each day there are several preset times that can be set to turn the lights off automatically.
The K25 has two channels that can control two different circuits separately such as one for the lights and the other for the fan.

(4) A/C Energy Saving

a/c can only turn on when the temperature is higher than the upper threshold
Controlling the air conditioning to prevent unnecessary energy wastage
  • The air conditioning can only be turned on by a combination of manual control and when the temperature is higher than the upper threshold.
  • When classes are over, the air conditioning will automatically be turned off at the designated time.