Systems and methods for controlling energy use in a building management system using energy budgets

1. A method for controlling power consumption by an HVAC system of a building, comprising:

using an energy use setpoint as a reference input for a feedback controller;

using a measured energy use as a measured input for the feedback controller;

using the feedback controller to generate a manipulated variable output for adjusting the operation of an HVAC device; and

calculating the energy use setpoint using a zone temperature threshold value and a history of building zone temperatures from a previous demand limiting period, wherein the energy use setpoint is estimated to cause the highest building zone temperature at the end of a demand limiting period to be less than or equal to the zone temperature threshold value.

2. The method of claim 1 , wherein the feedback controller is used to generate the manipulated variable output during a demand limiting period.

3. The method of claim 1 , wherein the measured energy use and the energy use setpoint are heat transfer rates or electrical power consumption rates.

4. The method of claim 1 , wherein the manipulated variable output is a temperature setpoint for a second controller that directly controls the HVAC device.

5. The method of claim 1 , wherein the manipulated variable output provides direct control over the HVAC device.

6. The method of claim 1 , wherein a thermal model of the building is not used to generate the manipulated variable output.

7. The method of claim 1 , further comprising:

adjusting the energy use setpoint based on pricing data received from an energy provider.

8. The method of claim 1 , wherein calculating the energy use setpoint comprises:

comparing a building zone temperatures at an end of the previous demand limiting period with a threshold value; and

adjusting the energy use setpoint for a second demand limiting period based on the comparison.

9. A method for controlling power consumption by an HVAC system of a building, comprising:

using an energy use setpoint as a reference input for a feedback controller;

using a measured energy use as a measured input for the feedback controller;

using the feedback controller to generate a manipulated variable output for adjusting the operation of an HVAC device; and

calculating the energy use setpoint by using a cost function that minimizes the financial cost of electrical power;

wherein the cost function comprises a probability that a particular energy use setpoint will cause the highest building zone temperature at the end of a demand limiting period to be less than or equal to a zone temperature threshold value and a financial cost associated with the probability.

10. The method of claim 9 , wherein the feedback controller is used to generate the manipulated variable output during a demand limiting period.

11. The method of claim 9 , wherein a thermal model of the building is not used to generate the manipulated variable output.

12. A feedback controller for controlling power consumption by an HVAC system of a building, the controller comprising:

a processing circuit configured to generate a value of a manipulated variable for adjusting the operation of an HVAC device, wherein the processing circuit comprises:

an error analyzer configured to receive an energy use setpoint as a reference input and to receive a measured energy use as a measured input, wherein the error analyzer is further configured to compare the reference input and the measured input, and to use the comparison to determine an error value;

an error corrector configured to receive the error value and to use the error value to generate the value of the manipulated variable; and

an energy use setpoint generator configured to calculate the energy use setpoint by using a cost function that minimizes the financial cost of electrical power used by the HVAC system, wherein the cost function comprises a probability that a particular energy use setpoint will cause the highest building zone temperature at the end of a demand limiting period to be less than or equal to a zone temperature threshold value and a financial cost associated with the probability.

13. A feedback controller for controlling power consumption by an HVAC system of a building, the controller comprising:

a processing circuit configured to generate a value of a manipulated variable for adjusting the operation of an HVAC device, wherein the processing circuit comprises:

an error analyzer configured to receive an energy use setpoint as a reference input and to receive a measured energy use as a measured input, wherein the error analyzer is further configured to compare the reference input and the measured input, and to use the comparison to determine an error value;

an error corrector configured to receive the error value and to use the error value to generate the value of the manipulated variable; and

an energy use setpoint generator configured to calculate the energy use setpoint using a zone temperature threshold value and a history of building zone temperatures from a previous demand limiting period, wherein the energy use setpoint is estimated to cause the highest building zone temperature at the end of a demand limiting period to be less than or equal to the zone temperature threshold value.

14. The feedback controller of claim 13 , wherein the error corrector is further configured to generate the manipulated variable during a demand limiting period.

15. The feedback controller of claim 13 , wherein the measured energy use and the energy use setpoint are heat transfer rates or electrical power consumption rates.

16. The feedback controller of claim 13 , wherein the manipulated variable is a temperature setpoint for a second controller that directly controls the HVAC device.

17. The feedback controller of claim 13 , wherein the manipulated variable is a direct control command for the HVAC device.

18. The feedback controller of claim 13 , wherein a thermal model of the building is not used by the processing circuit to generate the manipulated variable.

19. The feedback controller of claim 12 , wherein a thermal model of the building is not used by the processing circuit to generate the manipulated variable.

20. The feedback controller of claim 12 , wherein the error corrector is further configured to generate the manipulated variable during a demand limiting period.