Electrically controlled programmable digital thermostat and method for regulating the operation of multistage heating and cooling systems

• US 4,442,972 A
• Filed: 09/14/1981
• Issued: 04/17/1984
• Est. Priority Date: 09/14/1981
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Texas Instruments, Inc.
• Inventors: Sahay, Bharat B., Jones, James J.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US06/301,783
• Time in Patent Office: 946 Days
• Field of Search: 165/12, 165/29, 236/46 R, 236/1 R, 236/1 EA, 236/1 ER, 62/231
• US Class Current: 236/1.0EA
• CPC Class Codes: F23N 5/203 using electronic means
• CPC Class Codes: G05D 23/1904 variable in time

Abstract

An electronically controlled programmable wall thermostat provides better control of comfort temperature and permits improved energy-saving temperature setback at selected intervals of the day or night in multistage heating and cooling systems and is particularly useful in achieving improved energy savings for systems having heat pump means in the main temperature conditioning stage of the system. The thermostat includes clock means, temperature sensing means, means for displaying desired parameters of time and temperature, data entry and storage means for programming the thermostat to maintain desired temperatures during selected time intervals, and a processing means with a memory incorporating a permanently stored program instruction sequence which responds to signals from the temperature sensing means for controlling the heating and cooling systems in accordance with the time-temperature sequence programmed into the thermostat by the user. A novel method of temperature control is described in which the temperature sensing and processing means cooperate in a unique way to regulate operation of the main or heat pump stages of the heating and cooling systems relative to a programmed set temperature and to regulate operation of the auxiliary stages of the systems only with respect to the actual rate of change of temperature being effected by any operation of the system. In that way, the thermostat provides improved control of the comfort temperature under varying weather conditions and in different types of housing conditions and achieves timely and more energy-efficient recovery from setback temperatures at an optimum temperature restoring rate to result in more selective use of the heat pump means in the main stages of the systems.

Claims

1. Thermostat means for regulating a temperature conditioning system having independently operable main and auxiliary temperature conditioning means comprising means for sensing the temperature in a zone whose temperature is to be conditioned, means for scheduling temperatures to be provided in the zone during respective periods of time in a selected time sequence, and control means responsive both to the temperature sensing and scheduling means for operating the main temperature conditioning means when required in any of said time periods either to maintain a scheduled temperature in a period or to initiate conditioning of the zone temperature to provide the zone temperature scheduled to be provided in a next scheduled time period, said control means being responsive to the temperature sensing and scheduling means for comparing the zone temperature being provided in a time period with a temperature scheduled to be provided in that period, for comparing the zone temperature in any of said time periods with the temperature scheduled to be provided in the zone in the next scheduled time period in said time sequence to determine a time period when any operation of the main temperature conditioning means is required to be initiated for conditioning the zone temperature at a predetermined and desired rate of change of zone temperature to provide said next scheduled zone temperature at the start of said next time period, and to operate the main temperature conditioning means when required to maintain said scheduled zone temperature or at said determined time to initiate conditioning of the zone temperature to provide said next scheduled temperature, said control means being further responsive to the temperature sensing means for determining the actual rate of change of temperature then effected in the zone by the temperature conditioning means of the system during any operating thereof and for operating the auxiliary temperature conditioning means to aid the main temperature conditioning means in conditioning zone temperature only when said actual rate of change of zone temperature is less than said predetermined and desired rate of change of zone temperature.

2. An electronic thermostat for regulating independently operable main and auxiliary temperature conditioning means comprising:

(a) switch means actuable for selectively operating the main and auxiliary temperature conditioning means;

(b) means for sensing the temperature in a zone whose temperature is to be conditioned and for providing a signal indicative thereof;

(c) means for generating time signals;

(d) means for storing data selectively entered therein;

(e) data entry means for entering data into the storage means representative of selected temperatures scheduled to be provided in the zone during selected periods of time in a selected time sequence; and

(f) logic circuitry coupled to the data storage means and responsive to the temperature sensing and time signal generating means for actuating the switch means to operate the main temperature conditioning means when required in any of said time periods to initiate conditioning of the zone temperature to provide the zone temperature scheduled to be provided in that time period, said logic circuitry being adopted to compare the zone temperature in each of said time periods with the temperature to be provided in the zone in the next scheduled time period in said time sequence to determine a time prior to the start of said next scheduled time period when any operation of the main temperature conditioning means is required to be initiated for conditioning the zone temperature at a predetermined and desired rate of change in zone temperature to provide said next scheduled zone temperature at the start of said next time period and to actuate the switch means to operate the main temperature conditioning means at said determined time to initiate conditioning of the zone temperature to provide said next scheduled temperature, said logic circuitry being further responsive to the temperature sensing means to determine the actual rate of change of zone temperature then effected by the temperature conditioning means during any operation thereof and to actuate the switch means to operate the auxiliary temperature conditioning means to aid the main temperature conditioning means in conditioning zone temperature only when said actual rate of change of zone temperature is less than said predetermined and desired rate of change of zone temperature.

3. A programmable electronic digital thermostat for regulating independently operable main auxiliary temperature conditioning means comprising;

(a) switch means actuable for selectively operating the main and auxiliary temperature conditioning means;

(b) means for sensing the temperature in a zone whose temperature is to be conditioned and for providing a digital signal indicative of said temperature;

(c) means for generating time signals;

(d) first memory means for storing digital coded information into the first memory means representative of selected temperature scheduled to be provided in the zone during selected periods of time in a selected time sequence; and

(f) digital processor means having digital coded information constituting an instruction sequence permanently stored therein, said processor means being coupled to the first memory means and being adopted to respond to said time and temperature signals in accordance with said instruction sequence for actuating the switch means to operate the main temperature conditioning means when required in any of said time periods to initiate conditioning of the zone temperature to provide the zone temperature scheduled to be provided in that time period, said processor means having a predetermined and desired rate of change of zone temperature established as a constant and being adopted to determine the actual rate of change of zone temperature being effected by the temperature conditioning means during any operation thereof and to actuate the switch means to operate the auxiliary temperature conditioning means to aid the main temperature conditioning means in conditioning zone temperature at said selected constant selected rate to provide said scheduled temperature when said actual rate of change of zone temperature is less than said selected constant rate of change of zone temperature, said digital processor means comparing zone temperature in each of said time periods with the temperature to be provided in the zone in the next scheduled time period in said time sequence in accordance with said permanently stored instruction sequence to determine a time prior to the start of said next scheduled time period when any operation of the main temperature conditioning means is required to be initiated for conditioning the zone temperature at said predetermined and desired rate of change of zone temperature to provide said next scheduled zone temperature at the start of said next time period and to actuate said switch means to operate the main temperature conditioning means at said determined time.

4. A temperature conditioning system comprising main temperature conditioning means operable for conditioning the temperature in a zone, auxiliary temperature conditioning means operable to aid the main temperature conditioning means for conditioning the zone temperature, means for sensing temperature in the zone, means for scheduling temperatures to be provided in the zone during respective periods of time in a selected time sequence, and control means responsive to the temperature sensing and scheduling means for operating the main temperature conditioning means when required in any of said time periods to initiate conditioning of the zone temperature to provide the zone temperature scheduled to be provided in that time period, said control means being responsive to the temperature sensing and scheduling means for comparing the zone temperature in any of said time periods with the temperature scheduled to be provided in the zone in the next scheduled time period in said time sequence to determine a time prior to the start of said next scheduled time period when any operation of the main temperature conditioning means is required to be initiated for conditioning the zone temperature at a predetermined and desired rate of change of zone temperature to provide said next scheduled zone temperature at the start of said next time period and to operate the main temperature conditioning means at said determined time to initiate conditioning of the zone temperature to provide said next scheduled temperature, said control means being further responsive to the temperature sensing means for determining the actual rate of change of temperature then effected in the zone by the temperature conditioning means of the system during any operation thereof and for operating the auxiliary temperature conditioning means to aid the main temperature conditioning means in conditioning zone temperature only when said actual rate of change of zone temperature is less than said predetermined and desired rate of change of zone temperature.

5. A temperature conditioning system comprising main temperature conditioning means operable for conditioning the temperature in a zone, auxiliary temperature conditioning means operable to aid the main temperature conditioning means for conditioning the zone temperature, and a programmable electronic digital thermostat comprising;

(a) switch means actuable for selectively operating the main and auxiliary temperature conditioning means;

(b) means for sensing the temperature in a zone whose temperature is to be conditioned and for providing a ditial signal indicative of said temperature;

(c) means for generating time signals;

(d) first memory means for storing digital coded information selectively entered therein;

(e) data entry means for entering digital coded information into the first memory means representative of selected temperatures scheduled to be provided in the zone during selected periods of time in a selected time sequence; and

(f) digital processor means having digital coded information constituting an instruction sequence permanently stored therein, said processor means being coupled to the first memory means and being adopted to respond to said time and temperature signals in accordance with said instruction sequence for actuating the switch means to operate the main temperature conditioning means when required in any of said time periods to initiate conditioning of the zone temperature to provide the zone temperature scheduled to be provided in that time period, predetermined and desired rate of change of zone temperature established as a constant and being adopted to determine the actual rate of change of zone temperature being effected by the temperature conditioning means during any operation thereof and to actuate the switch means to operate the auxiliary temperature conditioning means to aid the main temperature conditioning means in conditioning zone temperature at said predetermined and desired constant rate to provide said scheduled temperature when said actual rate of change of zone temperature is less than said predetermined and desired rate of change of zone temperature, said digital processor means comparing zone temperature in each of said time periods with the temperature to be provided in the zone in the next scheduled time period in said time sequence in accordance with said permanently stored instruction sequence to determine a time prior to the start of said next scheduled time period when any operation of the main temperature conditioning means is required to be initiated for conditioning the zone temperature at said predetermined and desired rate of change of zone temperature to provide said next scheduled zone temperature at the start of said next time period and to actuate said switch means to operate the main temperature conditioning means at said determined time.

6. A temperature conditioning system as set forth in claim 5 wherein said main temperature conditioning means comprises heat pump means having relatively higher energy efficiency than said auxiliary temperature conditioning means.

7. A temperature conditioning system as set forth in claim 6 wherein said auxiliary temperature conditioning means comprises electrical resistance heater means.

8. A method for regulating operation of a temperature conditioning system having independently operable main and auxiliary temperature conditioning means comprising the steps of scheduling temperatures to be maintained in a zone during respective periods of time in a selected time sequence, continously sensing the zone temperature, comparing zone temperature sensed in each time period to the temperature scheduled to be provided in that period and operating the main temperature conditioning means when required to initiate conditioning of zone temperature to provide said scheduled temperature comparing the zone temperature sensed in each of said time periods with the temperature scheduled to be provided in the zone in the next scheduled time period in said time sequence and determining a time prior to the start of said next scheduled time period when any operation of the main temperature conditioning means is required to be initiated for conditioning the zone temperature at a predetermined and desired rate of change of zone temperature to provide said next scheduled temperature at the start of said next time period, initiating operation of the main temperature conditioning means at any such determined time to initiate conditioning of the zone temperature to provide said next scheduled temperature, and determining the actual rate of change of zone temperature being effected by the temperature conditioning means during any operation thereof and operating the auxiliary temperature conditioning means to aid the main temperature conditioning means in conditioning zone temperature when said actual rate of change of zone temperature is less than said predetermined and desired rate of change of zone temperature.