Central plant control system with time dependent deferred load

Patent metadata

Field	Value
Publication number	US-10900686-B2
Application number	US-201816048092-A
Country	US
Kind code	B2
Filing date	Jul 27, 2018
Priority date	Jul 28, 2017
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

In one aspect, a system for operations an energy plant obtains thermal energy load allocation data indicating time dependent thermal energy load of the energy plant. The system determines, for a time period, an operating state of the energy plant from a plurality of predefined operating states based on the thermal energy load allocation data. The system determines operating parameters of the energy plant according to the determined operating state. The system operates the energy plant according to the determined operating parameters.

First claim

What is claimed is:

1. A controller for an energy plant, the controller comprising:
a processing circuit comprising a processor and memory storing instructions executed by the processor, the processing circuit configured to:
obtain thermal energy load allocation data indicating time dependent thermal energy load of the energy plant;
use a relationship between the time dependent thermal energy load and a change in temperature of a fluid within a fluid loop represented by a dummy device to determine the change in temperature of the fluid based on the time dependent thermal energy load;
use an equivalence between the change in temperature of the fluid within the fluid loop and a change in temperature across the dummy device and a model that relates the time dependent thermal energy load to a flow rate of the fluid within the fluid loop to determine the flow rate of the fluid within the fluid loop;
determine operating parameters of the energy plant according to the flow rate and the fluid within the fluid loop;
operate the energy plant according to the operating parameters; and

wherein the processing circuit is configured to determine, for a time period, an operating state of the energy plant from a plurality of predefined operating states based on the thermal energy load allocation data, wherein the plurality of predefined operating states include at least one of:
a primary state, in which a supply device of the energy plant is enabled and a deferred load is allocated during the time period;
a deferred state, in which the supply device of the energy plant is disabled and the deferred load is allocated during the time period;
and an off-state, in which no load is allocated during the time period.

2. The controller of claim 1 , wherein the processing circuit is further configured to:
predict a power consumption of the energy plant according to the determined operating state.

3. The controller of claim 2 , wherein, responsive to determining that the operating state is the primary state, the processing circuit is configured to predict the power consumption of the energy plant according to a power consumption of the supply device.

4. The controller of claim 2 , wherein, responsive to determining that the operating state is the deferred state, the processing circuit is configured to:
determine the flow rate of the fluid through a load device to consume the deferred load during the time period; and
predict the power consumption according to the determined flow rate.

5. The controller of claim 4 , wherein the processing circuit is configured to:
generate a schematic data of the energy plant, the schematic data including a model of the dummy device in place of the supply device and a model of a load device to consume the deferred load;
determine the change in temperature in a loop formed by the model of the dummy device and the model of the load device; and
determine the flow rate, according to the determined change in temperature.

6. The controller of claim 2 , wherein, responsive to determining that the operating state is the off-state, the processing circuit is configured to:
determine that the supply device does not consume power during the time period.

7. The controller of claim 2 , wherein the processing circuit is further configured to:
determine, for another time period, another operating state of the energy plant from the plurality of predefined operating states based on the thermal energy load allocation data; and
predict another power consumption of the energy plant according to the another operating state.

8. The controller of claim 7 , wherein the processing circuit is further configured to:
compare the power consumption and the another power consumption; and
assign the time dependent thermal energy load to the energy plant for one of the time period and the another time period associated with a lower power consumption.

9. A method of operating an energy plant, the method comprising:
obtaining thermal energy load allocation data indicating time dependent thermal energy load of the energy plant;
using a relationship between the time dependent thermal energy load and a change in temperature of a fluid within a fluid loop represented by a dummy device to determine the change in temperature of the fluid based on the time dependent thermal energy load;
using an equivalence between the change in temperature of the fluid within the fluid loop and a change in temperature across the dummy device and a model that relates the time dependent thermal energy load to a flow rate of the fluid within the fluid loop to determine the flow rate of the fluid within the fluid loop;
determining operating parameters of the energy plant based on the flow rate of the fluid within the fluid loop;
operating the energy plant according to the operating parameters; and
determining, for a time period, an operating state of the energy plant from a plurality of predefined operating states based on the thermal energy load allocation data, wherein the plurality of predefined operating states include at least one of:
a primary state, in which a supply device of the energy plant is enabled and a deferred load is allocated during the time period;
a deferred state, in which the supply device of the energy plant is disabled and the deferred load is allocated during the time period;
and an off-state, in which no load is allocated during the time period.

10. The method of claim 9 , further comprising:
predicting a power consumption of the energy plant according to the determined operating state.

11. The method of claim 10 , further comprising:
predicting the power consumption of the energy plant according to a power consumption of the supply device, responsive to determining that the operating state is the primary state.

12. The method of claim 10 , responsive to determining that the operating state is the deferred state, the method further comprising:
determining the flow rate of the fluid through a load device to consume the deferred load during the time period; and
predicting the power consumption according to the determined flow rate.

13. The method of claim 12 , further comprising:
generating a schematic data of the energy plant, the schematic data including a model of the dummy device in place of the supply device and a model of a load device to consume the deferred load;
determine the change in temperature in a loop formed by the model of the dummy device and the model of the load device; and
determine the flow rate, according to the determined change in temperature.

14. The method of claim 10 , responsive to determining that the operating state is the off-state, the method further comprising:
determining that the supply device does not consume power during the time period.

15. The method of claim 10 , further comprising:
determining, for another time period, another operating state of the energy plant from the plurality of predefined operating states based on the thermal energy load allocation data; and
predicting another power consumption of the energy plant according to the another operating state.

16. The method of claim 15 , further comprising:
comparing the power consumption and the another power consumption; and
assigning the time dependent thermal energy load to the energy plant for one of the time period and the another time period associated with a lower power consumption.

17. A non-transitory computer readable medium comprising instructions when executed by a processor cause the processor to:
obtain thermal energy load allocation

Assignees

• Johnson Controls Tech Co

Inventors

• Willmott Graeme
• Burroughs John H
• Elbsat Mohammad N
• Wenzel Michael J
• Asmus Matthew J

Classifications

• F24F2140/00

  Control inputs relating to system states · CPC title

• F24F11/30

  for purposes related to the operation of the system, e.g. for safety or monitoring · CPC title

• F24F2140/50

  Load · CPC title

• F24F11/62

  characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values · CPC title

• F24F11/65

  for selecting an operating mode · CPC title