Adaptable control of HVAC systems

• US 5,170,935 A
• Filed: 11/27/1991
• Issued: 12/15/1992
• Est. Priority Date: 11/27/1991
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Federspiel, Clifford C., Asada, Harukiko
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US07/799,086
• Time in Patent Office: 384 Days
• Field of Search: 236/94, 236/91 C, 236/91 D, 236/91 R, 236/44 R, 236/44 C, 236/49.3, 62/161, 62/163, 62/164, 62/126, 62/127, 165/11.1, 165/12, 364/151, 364/148, 364/149, 364/557
• US Class Current: 236/44.00C
• 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 11/526 giving audible indications
• CPC Class Codes: F24F 11/56 Remote control
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 11/74 for controlling air flow rate or air velocity
• CPC Class Codes: F24F 11/79 for controlling the direction of the supplied air
• CPC Class Codes: F24F 11/86 by controlling compressors within refrigeration or heat pump circuits
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2110/20 Humidity
• CPC Class Codes: F24F 2110/40 Pressure, e.g. wind pressure
• CPC Class Codes: F24F 2120/00 Control inputs relating to users or occupants
• CPC Class Codes: F24F 2120/10 Occupancy
• CPC Class Codes: F24F 2120/20 Feedback from users
• CPC Class Codes: G05D 23/1902 characterised by the use of a variable reference value

Abstract

A system for providing adaptable control of an HVAC system which regulates environmental conditions within an enclosed area. In a preferred embodiment, the apparatus and method of the present invention measures selected environmental variables in the enclosed area, calculates a value of a comfort index which is a function of the values of the selected environmental variables and a plurality of parameters that predicts a thermal sensation rating of an occupant. The system receives an actual thermal sensation rating from the occupant and compares the predicted thermal sensation rating with the actual thermal sensation rating to determine a difference between the predicted thermal sensation rating and the actual thermal sensation rating. The system uses a parameter estimation process that estimates the value of at least one parameter in the plurality of parameters to reduce the difference between the predicted thermal sensation rating and the actual thermal sensation rating and then changes the value of at least one parameter, if necessary or desired. In one embodiment, the system repeats these steps until the thermal sensation rating provided by the occupant is substantially equal to neutral thermal sensation. In a preferred embodiment, the comfort index is an explicit, linearly parameterized function which represents the non-linear behavior of environmental variables.

Claims

1. An apparatus for providing adaptable control of an HVAC system which regulates environmental conditions in an enclosed area, comprising:

means for measuring values of selected environmental variables in the enclosed area;

means for calculating a value of a comfort index which is a function of the values of the selected environmental variables and a plurality of parameters that predicts a thermal sensation rating of an occupant of the enclosed area;

means for receiving an actual thermal sensation rating from the occupant;

means for comparing a value of a function of the predicted thermal sensation rating with a value of a function of the actual thermal sensation rating to determine a difference between the predicted thermal sensation rating and the actual thermal sensation rating;

parameter estimation means, responsive to the difference between the predicted thermal sensation rating and the actual thermal sensation rating, for estimating a value of at least one parameter in the plurality of parameters to reduce the difference between the predicted thermal sensation rating and the actual thermal sensation rating; and

means, responsive to the parameter estimation means, for changing the value of the at least one parameter.

2. The apparatus of claim 1 wherein the means for receiving an actual thermal sensation rating from the occupant includes means for receiving a plurality of actual thermal sensation ratings and the parameter estimation means estimates the value of the at least one parameter in the plurality of parameters in response to each respective actual thermal sensation rating until the actual thermal sensation rating received from the occupant is substantially equal to neutral thermal sensation.

3. The apparatus of claim 1 wherein the comfort index comprises an explicit, linearly parameterized function that represents a non linear behavior of the selected environmental variables.

4. The apparatus of claim 1 wherein the environmental variables include an air temperature, a humidity, an air velocity, and a mean radiant temperature.

5. The apparatus of claim 4 where in the environmental variables further include a rate of bodily heat production, a clothing temperature, and a mechanical efficiency of a human body.

6. The apparatus of claim 1 wherein the comfort index, is expressed as ##EQU7## where θ

_o through θ

₆ are constant parameters defined as;

##EQU8##

7. The apparatus of claim 1, wherein the means for receiving an actual thermal sensation rating from the occupant includes a user interface having a psycho-physical rating scale and means for the occupant to register the actual thermal sensation rating via the user interface.

8. The apparatus of claim 7 wherein the psycho-physical rating scale is bipolar.

9. A method for providing adaptable control of an HVAC system which regulates environmental conditions in an enclosed area, comprising:

(a) measuring values of selected environmental variables in the enclosed area;

(b) calculating a value of a comfort index which is a function of the values of the selected environmental variables and a plurality of parameters that predicts a thermal sensation rating of an occupant of the enclosed area;

(c) receiving an actual thermal sensation rating from the room occupant;

(d) comparing a value of a function of the predicted thermal sensation rating with a value of a function of the actual thermal sensation rating to determine a difference between the predicted thermal sensation rating and the actual thermal sensation rating;

(e) estimating a value of at least one parameter in the plurality of parameters to reduce the difference between the predicted thermal sensation rating and the actual thermal sensation rating; and

(f) changing the value of the at least one parameter in response to an estimated value of the at least one parameter.

10. The method of claim 9, further comprising repeating steps c, d, e, and f.

11. The method of claim 10, further comprising repeating steps c, d, e, and f until the actual thermal sensation rating received from the room occupant is substantially equal to neutral thermal sensation.

12. The method of claim 10, wherein the step of calculating a value of a comfort index includes calculating the value of an explicit, linearly parameterized function that represents a non linear behavior of the selected environmental variables.

13. The method of claim 10, wherein the step of measuring selected environmental variables includes measuring an air temperature, a humidity, an air velocity, and a mean radiant temperature.

14. The method of claim 13 wherein the step of measuring selected environmental variables further includes measuring rate of bodily heat production, clothing temperature, and mechanical efficiency of a human body.

15. The method of claim 11 wherein the step of calculating a value of a comfort index further comprises calculating the value of ##EQU9## where θ

_o through θ

₆ are constant parameters defined as;

##EQU10##

16. In an HVAC system controller which predicts a thermal sensation rating of an occupant of an enclosed area by calculating a value of a comfort index which is a function of the values of selected environmental variables and a plurality of parameters that predicts thermal sensation rating of an occupant of the enclosed area and controls environmental conditions within the enclosed area in response to the value of the comfort index, the improvement comprising:

means for receiving an actual thermal sensation rating from the occupant;

means for comparing a value of a function of the predicted thermal sensation rating with a value of a function of the actual thermal sensation rating to determine a difference between the predicted thermal sensation rating and the actual thermal sensation rating;

parameter estimation means, responsive to the difference between the predicted thermal sensation rating and the actual thermal sensation rating, for estimating a value of at least one parameter in the plurality of parameters to reduce the difference between the predicted thermal sensation rating and the actual thermal sensation rating; and

means, responsive to the parameter estimation means, for changing the value of the at least one parameter.