Temperature control system using a single ramp rate curve for control of a multiplant environmental unit

• US 4,702,413 A
• Filed: 05/07/1987
• Issued: 10/27/1987
• Est. Priority Date: 05/07/1987
• Status: Expired due to Fees

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Beckey, Thomas J., Uhrich, Daniel T., Kallas, Kerry M.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US07/046,766
• Time in Patent Office: 173 Days
• Field of Search: 236/46 R, 236/78 D, 165/12, 165/29, 62/231, 364/557, 364/505, 307/39
• US Class Current: 236/46.00R
• CPC Class Codes: F24D 19/1039 the system uses a heat pump
• CPC Class Codes: G05D 23/1904 variable in time
• CPC Class Codes: G05D 23/1919 characterised by the type of controller

Abstract

A temperature control system for a multiplant environmental unit such as a heat pump with auxiliary heat is disclosed. The control system utilizes a thermostat having a microprocessor and memory that allows for energy savings through setback functions. The setback functions return the temperature control from a setback temperature to a normal comfort temperature along a ramped rate that is modified from day to day. The purpose of this variable ramp is to minimize the operation of the auxliary heat and maximize shell savings (by starting as late as possible). This is basically accomplished by locking the heat pump on in certain cases.

Claims

1. A temperature control system for control of a multiplant environmental unit for tempering the atmosphere in an enclosed space in an energy efficient manner, including:

a multiplant environmental unit having at least a first output and a second output;

said first output being more cost effective to operate than said second output;

real time clock operated two stage thermostat means located in said space;

said thermostat means including means to enter selected times and temperatures, and further including means to sense an ambient temperature in said space;

said thermostat means having a selected comfort setpoint temperature, and further having a selected energy savings setback setpoint temperature to define limits of the operation of said multiplant environmental unit over a temperature control cycle;

said thermostat means including microcomputer means having memory means;

said memory means storing a time versus temperature curve with said curve selected to utilize said first output, or both outputs simultaneously which causes said atmosphere to change from said energy savings setback setpoint temperature to said comfort setpoint temperature;

a first stage of said thermostat means operating said multiplant environmental unit upon said sensor temperature intersecting said operating curve which then locks on said first output;

a second stage of said thermostat means operating said second output;

said thermostat means ending a recovery and shifting to said selected comfort setpoint temperature upon said sensor temperature reaching a specified value below said setpoint temperature, or upon the expiration of a setback time programmed in said memory means; and

said memory means storing a time of said ending recovery and increasing or decreasing a ramprate of said time versus temperature curve for a next temperature control cycle depending on whether said end of recovery time occurred before said setback time.

2. A temperature control system for a multiplant environmental unit as claimed in claim 1 wherein said memory means stores a plurality of time versus temperature curves for use at different periods of time.

3. A temperature conrol system for a multiplant environmental unit as claimed in claim 1 wherein said time versus temperature curve has a minimum ramp rate slope that is enforced by said thermostat means to ensure at least a minimum amount of setback energy savings.

4. A temperature control system for a multiplant environmental unit as claimed in claim 3 wherein said time versus temperature curve has a maximum ramp rate slope that is enforced by said thermostat means to ensure at least a minimum amount of time is available for a recovery from said selected energy savings setback setpoint temperature to said selected comfort setpoint temperature.

5. A temperature control system for a multiplant environmental unit as claimed in claim 4 wherein said memory means stores a plurality of time versus temperature curves for use a different periods of time.

6. A real time clock operated two stage thermostat means for control of a multiplant environmental unit having at least a first output and a second output with said first output being more cost effective to operate than said second output for tempering the atmosphere in an enclosed space in an energy efficient manner, including:

said thermostat means located in said space;

said thermostat means including means to enter selected times and temperatures, and further including means to sense an ambient temperature in said space;

said thermostat means having a selected comfort setpoint temperature, and further having a selected energy savings setback setpoint temperature to define limits of the operation of said multiplant environmental unit over a temperature control cycle;

said thermostat means including microcomputer means having memory means;

said memory means storing a time versus temperature curve with said curve selected to utilize said first output, or both outputs simultaneously which causes said atmosphere to change from said energy savings setback setpoint temperature to said comfort setpoint temperature;

a first stage of said thermostat means operating said multiplant environmental unit upon said sensor temperature intersecting said operating curve which then locks on said first output;

a second stage of said thermostat means operating said second output;

said thermostat means ending a recovery and shifting to said selected comfort setpoint temperature upon said sensor temperature reaching a specified value below said setpoint temperature, or upon the expiration of a setback time programmed in said memory means; and

said memory means storing a time of said end of recovery and increasing or decreasing a ramprate of said time versus temperature curve for a next temperature control cycle depending on whether said end of recovery time occurred before said setback time.

7. A temperature control system for a multiplant environmental unit as claimed in claim 6 wherein said memory means stores a plurality of time versus temperature curves for use at different periods of time.

8. A temperature conrol system for a multiplant environmental unit as claimed in claim 6 wherein said time versus temperature curve has a minimum ramp rate slope that is enforced by said thermostat means to ensure at least a minimum amount of setback energy savings.

9. A temperature control system for a multiplant environmental unit as claimed in claim 8 wherein said time versus temperature curve has a maximum ramp rate slope that is enforced by said thermostat means to ensure at least a minimum amount of time is available for a recovery from said selected energy savings setback setpoint temperature to said selected comfort setpoint temperature.

10. A temperature control system for a multiplant environmental unit as claimed in claim 9 wherein said memory means stores a plurality of time versus temperature curves for use a different periods of time.