MPC for HVAC with thermal model selection
An example control device includes memory storing a first thermal model of a building and a second thermal model of the building, and a processor connected to the memory. The processor is configured to select the first thermal model or the second thermal model as a selected thermal model, and execute model predictive control (MPC) using the selected thermal model to control a heating, cooling, ventilation, and/or air conditioning (HVAC) apparatus at the building.
1. A device comprising:
memory storing a first thermal model of a building and a second thermal model of the building;
a processor connected to the memory, the processor configured to:
obtain an operational parameter of a heating, cooling, ventilation, and/or air conditioning (HVAC) apparatus at the building;
compare the operational parameter to a threshold;
when the operational parameter exceeds the threshold, select the first thermal model as a selected thermal model;
when the operational parameter does not exceed the threshold, select the second thermal model as the selected thermal model; and
execute model predictive control using the selected thermal model to control the HVAC apparatus at the building;
determine an error between a sensed HVAC condition of the building and a predicted HVAC condition predicted by the selected thermal model; and
when the error exceeds an error tolerance, disable the model predictive control and enable a reactive control algorithm to control the HVAC apparatus.
2. The device of claim 1 , wherein the operational parameter is a setpoint of the HVAC apparatus.
3. The device of claim 1 , wherein the operational parameter is a mode of the HVAC apparatus.
4. The device of claim 1 , wherein the operational parameter is a time.
5. The device of claim 1 , wherein the first thermal model and the second thermal model are linear models.
6. The device of claim 1 , wherein each of the first and second thermal models model:
a building envelope;
an operational output of the HVAC apparatus; and
a disturbance.
7. The device of claim 6 , wherein the disturbance comprises solar heating, wind, a building occupant, appliance heat generation, or a door being opened or closed.
8. The device of claim 6 , wherein each of the first and second thermal models further models a thermal mass of furniture in the building.
9. The device of claim 1 , wherein the processor is further configured to generate the first thermal model and the second thermal model.
10. The device of claim 1 , wherein the processor is further configured to:
generate a non-linear thermal model of the building; and
perform a piecewise segmentation on the non-linear thermal model to generate the first and second thermal models.
11. The device of claim 10 , wherein the processor is further configured to generate the non-linear thermal model of the building during a training period of operation of the HVAC apparatus.
12. The device of claim 1 , wherein the model predictive control is configured with a comfort constraint and an objective to minimize an operating cost of the HVAC apparatus due to a price of energy.
13. The device of claim 12 further comprising a network interface connected to the processor, the network interface to receive the price of energy from a computer network.
14. The device of claim 1 , wherein the model predictive control is configured with a comfort constraint and an objective to minimize an operating cycle frequency of the HVAC apparatus.
15. The device of claim 1 , wherein the processor is configured to execute the model predictive control at predetermined intervals.
16. The device of claim 1 , further comprising a housing containing the memory and the processor.
17. The device of claim 16 , wherein the housing is configured to be attached to a wall of the building or be placed on a surface inside the building.
18. The device of claim 1 , further comprising a network interface connected to the processor, wherein the processor is configured to execute the model predictive control irrespective of an availability of a network connection at the network interface.