Method for controlling an air conditioning system

• US 4,407,139 A
• Filed: 10/07/1981
• Issued: 10/04/1983
• Est. Priority Date: 10/13/1980
• Status: Expired due to Term

• Current Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
• Original Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
• Inventors: Nukushina, Harunobu, Ide, Yuuichi
• Primary Examiner(s): Makay, Albert J.
• Assistant Examiner(s): TANNER, HARRY B
• Application Number:
  US06/309,413
• Time in Patent Office: 727 Days
• Field of Search: 62/229, 62/228 B, 62/228 C, 62/226, 62/225, 62/215, 62/157, 62/158, 62/231, 165/12, 165/26, 165/41, 165/42, 165/43, 165/44, 236/1 EA, 236/46 F, 236/1 EB, 236/46 R, 236/78
• US Class Current: 62/215
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/52 Indication arrangements, e.g. displays
• CPC Class Codes: F24F 11/61 using timers
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 11/84 using valves
• CPC Class Codes: F24F 11/86 by controlling compressors within refrigeration or heat pump circuits
• CPC Class Codes: F24F 11/88 Electrical aspects, e.g. circuits
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2140/00 Control inputs relating to system states
• CPC Class Codes: F25B 2600/021 Inverters therefor
• CPC Class Codes: F25B 49/025 Motor control arrangements
• CPC Class Codes: G05D 23/1912 whose output amplitude can take more than two discrete values
• CPC Class Codes: G05D 23/20 with sensing elements having variation of electric or magnetic properties with change of temperature G05D23/13 takes precedence
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

In a method for controlling an air conditioning system including a frequency-variable power source device for providing an AC electric power of a variable frequency, and a compressor driven by the AC electric power, the air conditioning power of the conditioning system being dependent on the frequency of the AC electric power, the temperature of the air to be conditioned is detected; and a frequency set value is determined in accordance with a deviation of the detected temperature with reference to a set temperature. For determining the frequency set value, a plurality of temperature deviation zones are defined; the frequency set value is changed when the deviation transits from one of the zones to another; and the frequency set value is also changed when the deviation continues to be within one of the zones of a relatively great deviation over a predetermined length of time.

Claims

1. A method for controlling an air conditioning system including a frequency-variable power source device for providing an AC electric power of a variable frequency, and a compressor driven by said AC electric power, the air conditioning power of said conditioning system being dependent on the frequency of said AC electric power, said method comprising the steps of:

detecting the temperature of the air to be conditioned,

providing a set value for the air temperature,

determining a deviation for the detected temperature with reference to the set temperature,

determining a frequency set value in accordance with said deviation, and

providing a frequency setting signal indicative of said frequency set value used to determine the frequency of said AC electric power,

said step of determining the frequency set value comprising;

defining, in advance, a plurality of temperature deviation zones, each zone being defined by upper and lower threshold values,

determining, by comparing said deviation with said upper and lower threshold values, the zone in which said deviation is in,

determining an initial frequency set value in accordance with said deviation,

changing the frequency set value when said deviation transits from one of the zones to another, and

changing the frequency set value when said deviation continues to be within one of the zones corresponding to a relatively great deviation over a predetermined length of time.

2. A method according to claim 1, wherein the frequency set value is increased by a predetermined amount when the deviation transits from one of the zones to another zone requiring a higher air conditioning power than that required before the transition, and the frequency set value is decreased by a predetermined amount when the deviation transits from one of the zones to another zone requiring a lower air conditioning power than that required before the transition.

3. A method according to claim 2, wherein the frequency set value is set at zero when the deviation transits to the zone of the deviation requiring the lowest air conditioning power.

4. A method according to claim 1, wherein the frequency set value is increased by a predetermined amount when the deviation continues, over a predetermined length of time, to be within one of the zones requiring higher air conditioning power than that required when the deviation is approximately zero, and the frequency set value is decreased by a predetermined amount when the deviation continues, over a predetermined length of time, to be within one of the zones requiring lower air conditioning power than that required when the deviation is approximately zero.

5. A method according to claim 4, wherein the frequency set value for the zone of the deviation requiring the lowest air conditioning power is initially set at zero and is not changed even when the deviation continues, over the predetermined length of time, to be within said zone.

6. A method according to claim 1, wherein the upper threshold value set for transition of the deviation into a predetermined zone is lower than the upper threshold value set for transition from the predetermined zone, and the lower threshold value set for transition of the deviation into the predetermined zone is higher than the lower threshold value set for transition from the predetermined zone.