Patent Description:
A chiller can generally be used in a heating, ventilation, air conditioning, and refrigeration (HVACR) system to remove heat from a process fluid (e.g., water or the like) via a refrigeration cycle (e.g., a vapor compression cycle). The chiller can be configured to cool the process fluid to a specific temperature set point(s) based on, for example, a primary function of the process fluid. In some situations, for example, the process fluid may be used to provide sensible cooling to a building or an enclosed space, for which the temperature of the process fluid may be in a range of, for example, at or about <NUM> °F to at or about <NUM> °F. In some situations, for example, a chiller may be configured to provide a relatively cold process fluid (e.g., in a range of at or about <NUM>°F to at or about <NUM>°F) to an air-handling unit for dehumidification.

As prior art there may be mentioned <CIT>, which discloses a temperature and humidity independent regulation air-conditioning system comprising an air-handling system, a high temperature water chilling unit, an ice-making main machine, an ice slurry unit, an ice storage pool, a high temperature cold source heat exchanger and a large temperature difference low temperature cold source heat exchanger. The air-handling system is connected with the high temperature water chilling unit, the high temperature cold source heat exchanger and the large temperature difference low temperature cold source heat exchanger respectively so that heat exchange can be conducted. The ice-making main machine, the ice slurry unit and the ice storage pool are connected in sequence. The high temperature cold source heat exchanger is connected with the ice storage pool. The large temperature difference low temperature cold source heat exchanger is connected with the ice storage pool.

A chiller plant according to claim <NUM> is disclosed. The chiller plant includes a chiller circuit including a chiller and a process fluid circuit. The chiller is configured to provide a process fluid at a first temperature. The chiller plant also includes an air handling circuit including a plurality of ice storage tanks and an air handling unit.

A chiller plant is disclosed. The chiller plant includes a chiller circuit including a chiller, a first process fluid circuit, and a first heat exchanger. The chiller is configured to provide a first process fluid at a first temperature. The chiller plant also includes an air handling circuit including a plurality of ice storage tanks and an air handling unit. The chiller plant further includes a terminal cooling circuit including a plurality of terminals, the terminal cooling circuit providing a second process fluid to the plurality of terminals at a second temperature that is different from the first temperature. The terminal cooling circuit is fluidly separate from, but thermally communicates with, the chiller circuit via the first heat exchanger.

A method according to claim <NUM> of operating the chiller plant of claim <NUM> is also disclosed. The method includes receiving, by a controller, a plurality of operating factor inputs from one or more sensors in a chiller plant. The controller determines an operating mode and a setpoint based on the plurality of operating factors. The method further includes sending, by the controller, operating states to one or more components of the chiller plant to place the chiller plant in the operating mode and at the setpoint as determined.

References are made to the accompanying drawings which illustrate embodiments in which the systems and methods described in this specification can be practiced.

A chiller can generally be used in an HVACR system to remove heat from a process fluid (e.g., water or the like) via a refrigeration cycle (e.g., a vapor compression cycle). The chiller can be configured to cool the process fluid to a specific temperature set point(s) based on, for example, a primary function of the process fluid. To provide the process fluid at multiple temperatures, some HVACR systems include a plurality of chillers. In other HVACR systems, a chiller may be used to provide sensible cooling and a separate system may be used for dehumidification.

A chiller generally includes a refrigerant circuit (see <FIG> and its corresponding description below). In an embodiment, a single chiller includes a refrigerant circuit. In an embodiment, a plurality of chillers can be connected in parallel. In an embodiment, the chiller can include a water side economizer.

This disclosure is directed to a dual temperature chiller plant that uses a chiller to provide a process fluid (e.g., water or the like) at multiple temperatures (or temperature ranges) to provide the process fluid for purposes of sensible cooling and/or dehumidification. In an embodiment, the dual temperature chiller plant (hereinafter "chiller plant") includes ice storage tanks. The ice storage tanks can, for example, store ice that can be frozen for later use. In an embodiment, the ice may be frozen during unoccupied hours (e.g., nighttime, etc.). During occupied hours the ice from the ice storage tanks can be melted to produce the relatively colder process fluid used to accomplish dehumidification. In an embodiment, the chiller plant including ice storage tanks can, for example, be more efficient than alternative options which might rely upon operating in a condition in which the relatively colder process fluid is used and is blended with a relatively warmer process fluid or an intermediate heat exchanger. In an embodiment, a chiller may be about <NUM> to about <NUM> percent more efficient per degree of temperature elevation of the process fluid. For example, if the process fluid is <NUM> to <NUM> degrees Fahrenheit warmer, the energy consumed can be reduced by <NUM> to <NUM> percent.

It will be appreciated that the classification of the building as being occupied or unoccupied is not intended to be limited. Accordingly, a building may include some occupants during unoccupied hours or may not include occupants during occupied hours. Further, these periods are intended to be examples. It will be appreciated that the various principles described in this specification can be applied during occupied or unoccupied hours. Furthermore, the occupied and unoccupied times are not intended to be limited to daytime or nighttime. Accordingly, the discussion of occupied, unoccupied, daytime, or nighttime classifications that follows is intended as an example, but can vary according to the principles described in this specification.

<FIG> is a schematic diagram of an HVACR system <NUM> that includes a chiller plant <NUM> and other components of the HVACR system <NUM>, according to an embodiment. The other components of the HVACR system <NUM> can include, for example, various terminal devices/systems including, but not limited to, a sensible cooling terminal 14A and/or an air handling unit (AHU) 14B.

In the illustrated embodiment, three terminals 14A are shown. It will be appreciated that the number of terminals 14A is illustrative and can vary based on, for example, a building in which the HVACR system <NUM> is implemented. The terminals 14A can include radiant cooling (e.g., panels or tubing which can be embedded into a building structure); chilled beams (e.g., active or passive); fan-powered terminals (e.g., fan-coils, fan-powered VAV terminals with sensible cooling coils, etc.); as well as suitable combinations thereof.

The chiller plant <NUM> includes a chiller <NUM>. In the illustrated embodiment, a single chiller <NUM> is shown. It will be appreciated that one or more additional chillers may be included in parallel with the chiller <NUM>. Such an embodiment may be used, for example, to provide additional capacity for a larger building. The chiller <NUM> can be configured to provide a process fluid (e.g., water, glycol, and/or a mixture of water and glycol, and the like) at a temperature T <NUM>. The temperature T1 can vary according to an operating mode of the chiller <NUM>. An operating mode can include a configuration selected to control the chiller <NUM> and its outputs, for example, to accomplish a particular environmental control goal (e.g., sensible cooling or dehumidification) or to make ice for the ice storage tanks <NUM>. For example, the operating mode can be selected to provide sensible cooling and/or dehumidification to the building. <FIG>, described in further detail below, show configurations of the HVACR system <NUM> according to various operating modes.

The HVACR system <NUM> includes the chiller plant <NUM> and a terminal cooling circuit <NUM>. The chiller plant <NUM> includes a chiller circuit 12A and an air handling circuit 12B. In an embodiment, the air handling circuit 12B can be alternatively referred to as the outdoor air handling circuit 12B, or the like. The chiller circuit 12A includes a process fluid circuit that generally includes a system or fluid circuit that may include, as appropriate, pipes, lines, pumps, valves, and the like, that are configured to direct a process fluid conditioned by the chiller <NUM>. The air handling circuit 12B includes a process fluid circuit that generally includes a system or fluid circuit that may include, as appropriate, pipes, lines, pumps, valves, etc., that are configured to direct a process fluid to the AHU 14B. The terminal cooling circuit <NUM> includes a process fluid circuit that generally includes a system or fluid circuit including pipes, lines, pumps, valves, etc., that are configured to direct a process fluid to the terminals 14A.

In an embodiment, the chiller circuit 12A includes the chiller <NUM>, a flow control device <NUM>, a heat exchanger <NUM>, and a plurality of pumps 34A, 34B fluidly connected. The pumps 34A, 34B can be used to circulate the process fluid throughout the chiller circuit 12A. The chiller <NUM> is not intended to be limited to a particular chiller design. For example, the chiller <NUM> can be an air-cooled chiller, a water-cooled chiller, or the like. The chiller <NUM> includes a refrigerant circuit (not shown) configured to output the process fluid (e.g., water and/or glycol) at the temperature T1. In the illustrated embodiment, the temperature T1 may be at or about <NUM> °F. As illustrated in <FIG>, the chiller circuit 12A can further include a heat exchanger <NUM> and a flow control device <NUM>. The heat exchanger <NUM> and flow control device <NUM> are illustrated within dashed lines because the heat exchanger <NUM> is optional. The heat exchanger <NUM> can be used for cooling (and in an embodiment, dehumidification as well) and can be the same as or similar to a heat exchanger of the AHU 14B. In an embodiment, including the heat exchanger <NUM> can reduce a cooling load on the heat exchanger of the AHU 14B. Reducing the cooling load on the heat exchanger of AHU 14B can, in an embodiment, reduce a size and/or number of the ice storage tanks <NUM> included in the HVACR system <NUM>. In an embodiment, including the heat exchanger <NUM> can provide an increase in efficiency of the HVACR system <NUM> over an HVACR system <NUM> that does not include the heat exchanger <NUM>. In an embodiment, the chiller circuit 12A can include a chiller minimum flow bypass <NUM> capable of fluidly connecting upstream of the flow control device <NUM> and upstream of the pumps 34A, 34B. A flow control device <NUM> can be used to enable or disable the chiller minimum flow bypass <NUM>.

The chiller circuit 12A and the air handling circuit 12B are fluidly connectable. In the illustrated embodiment, the chiller circuit 12A and the air handling circuit 12B are fluidly separated by, for example, preventing flow of the process fluid between the circuits 12A, 12B. The flow can be controlled using flow control devices <NUM>, <NUM>, and <NUM>. The flow control devices <NUM>, <NUM>, and <NUM> can be, for example, valves. In an embodiment, the flow control devices <NUM> and <NUM> can be two-way valves having a flow enabled state and a flow disabled state. The flow control device <NUM> can be a three-way flow control device that includes a flow enabled state and a flow disabled state for the three connections. In the illustrated embodiment, the flow control devices <NUM> and <NUM> are in the flow disabled state. The flow control device <NUM> is in a flow enabled state within the air handling circuit 12B. The flow control device <NUM> is in a flow disabled state for a connection between the air handling circuit 12B and a location that is downstream of the heat exchanger <NUM> in the chiller circuit 12A. In these states, the chiller circuit 12A and the air handling circuit 12B are fluidly separated.

In the illustrated embodiment, the chiller circuit 12A can be fluidly separated from the terminal cooling circuit <NUM>. The chiller circuit 12A is in thermal communication with the terminals 14A via the heat exchanger <NUM>. This arrangement can be selected so that the process fluid provided to the terminals 14A is a different process fluid than the process fluid used by the chiller <NUM>. For example, the chiller <NUM> can use a process fluid that includes a mixture of water and glycol, whereas the terminals 14A can be provided with a process fluid that includes water without glycol. It will be appreciated that the terminals 14A and the chiller <NUM> can use the same process fluid. In an embodiment, when the terminals 14A and the chiller <NUM> use the same process fluid, the heat exchanger <NUM> may be removed from the HVACR system <NUM>. Such an embodiment is shown and described in accordance with <FIG>. In operation, the terminal cooling circuit <NUM> can provide a process fluid at a temperature T2. In an embodiment, the temperature T2 can be at or about <NUM> °F. In an embodiment, the temperature T2 can be from at or about <NUM> °F to at or about <NUM> °F.

The air handling circuit 12B includes ice storage tanks <NUM> fluidly connected with the AHU 14B and a plurality of pumps 40A, 40B. In the illustrated embodiment, two ice storage tanks <NUM> are shown. It will be appreciated that the number of ice storage tanks <NUM> can vary. That is, in an embodiment, there can be a single ice storage tank <NUM>. In an embodiment, there can be more than two ice storage tanks <NUM>. For example, the number of ice storage tanks <NUM> can be based on cooling requirements of the building for which the system <NUM> is being used. In an embodiment, the ice storage tanks <NUM> can be rated based on a number of ton-hours of stored cooling energy and a particular configuration selected based on the number of ton-hours of stored cooling energy relative to the cooling demands of the HVACR system <NUM>. The air handling circuit 12B generally includes a same process fluid as the process fluid used by the chiller <NUM>. That is, if the chiller <NUM> includes a process fluid that is a combination of water and glycol, then the air handling circuit 12B includes a process fluid that is a combination of water and glycol.

In the illustrated embodiment, the chiller <NUM> can generally provide the process fluid at the temperature T1. The process fluid is in a heat exchange relationship with the terminals 14A via the heat exchanger <NUM> and can exchange heat from the process fluid in the chiller circuit 12A to the process fluid in the terminal cooling circuit <NUM>, thereby providing the process fluid to the terminals 14A at the temperature T2. The air handling circuit 12B can use melting of the ice in the ice storage tanks <NUM> to provide the process fluid at a temperature T3 to the AHU 14B. In an embodiment, the temperature T3 can be at or about <NUM> °F. In an embodiment, the temperature T3 can be from at or about <NUM> °F to at or about <NUM> °F. The operating mode shown in <FIG> may be representative of an operating mode in which the building of the HVACR system <NUM> is occupied. In an embodiment, the occupied operating condition may be generally referred to as a daytime operating mode.

<FIG> are schematic diagrams showing configurations for the HVACR system <NUM> shown in <FIG> in various operating modes.

<FIG> represents an operating condition in which the ice from the ice storage tanks <NUM> may be used to provide sensible cooling via the terminals 14A and dehumidification via the AHU 14B, according to an embodiment. The operating mode shown in <FIG> may be an alternative daytime operating mode relative to <FIG>. The operating mode in <FIG> may be generally operational when the building of the HVACR system <NUM> is occupied.

In the illustrated embodiment, the process fluid provided from the chiller <NUM> may be provided at a temperature that is greater than the temperature T1. In an embodiment, operating the chiller <NUM> to provide the relatively warmer process fluid may, for example, reduce an amount of energy consumed by the chiller <NUM>. In the illustrated embodiment, the flow control devices <NUM> and <NUM> are in the flow enabled state. Accordingly, the chiller circuit 12A and the air handling circuit 12B are fluidly connected. Because of the fluid connection, ice that is melting from the ice storage tanks <NUM> and is at a temperature lower than T1 can be mixed with the process fluid from the chiller <NUM>. As a result, the process fluid can leave the chiller <NUM> at a temperature that is greater than T1, but be cooled to the temperature T1 at a location that is upstream of the heat exchanger <NUM>. As a result, the process fluid provided to the terminals 14A can be provided at the temperature T2, even when the chiller <NUM> is outputting the process fluid at a temperature that is greater than the temperature T1. The melting ice from the ice storage tanks <NUM> can be used to provide a process fluid at the temperature T3. The process fluid at the temperature T3 can be provided to the AHU 14B for dehumidification.

<FIG> represents an operating condition in which the chiller <NUM> can be used for both sensible cooling via the terminals 14A and dehumidification via the AHU 14B, according to an embodiment. The operating mode shown in <FIG> may be an alternative daytime operating mode relative to <FIG> and <FIG>. The operating mode in <FIG> may be generally operational when the building of the HVACR system <NUM> is occupied.

In the illustrated embodiment, the process fluid provided from the chiller <NUM> may be provided at the temperature T3. In the illustrated embodiment, the flow control device <NUM> can be in the flow disabled state. The flow control device <NUM> can be in the flow enabled state. The flow control device <NUM> can be in a state in which flow is disabled between the chiller <NUM> and the flow control device <NUM>. The flow control device <NUM> can be in a state where flow is enabled between the AHU 14B and the flow control device 28The flow control device <NUM> is also in the flow enabled state between the flow control device <NUM> and a location of the chiller circuit 12A that is downstream of the heat exchanger <NUM>. The state of the flow control devices <NUM>, <NUM>, and <NUM>, enables fluid communication between the chiller circuit 12A and the air handling circuit 12B. However, the ice storage tanks <NUM> are fluidly separated from the air handling circuit 12B by placing a flow control device <NUM> in a flow disabled state. In such an embodiment, the ice storage tanks <NUM> may, for example, be empty or have an insufficient amount of ice to provide the process fluid at the temperature T3. The chiller <NUM> can provide the process fluid at the temperature T3. In the illustrated embodiment, the process fluid can be provided to the AHU 14B at the temperature T3. The diverted state of the flow control device <NUM> returns the process fluid to a location that is downstream of the heat exchanger <NUM>. The heat exchange via the heat exchanger <NUM> can be used to exchange heat between the process fluid in the chiller circuit 12A and the process fluid in the terminal cooling circuit <NUM> so that the process fluid provided to the terminals 14A is at the temperature T2.

<FIG> represents an operating condition in which the chiller <NUM> can be used to make ice for the ice storage tanks <NUM>, according to an embodiment. The operating mode shown in <FIG> may be an operating mode that is enabled, for example, when the building of the HVACR system <NUM> is unoccupied. Accordingly, the operating mode in <FIG> may alternatively be referred to as the nighttime operating mode in an embodiment.

In the illustrated embodiment, the process fluid can be provided from the chiller <NUM> at a temperature T4. In an embodiment, the temperature T4 can be from at or about <NUM> °F to at or about <NUM> °F. The chiller <NUM> may be fluidly connected with the ice storage tanks <NUM> to freeze ice for later use. In the illustrated embodiment, the flow control device <NUM> and the flow control device <NUM> may be in the flow enabled state. A flow control device <NUM> may be in a flow disabled state to prevent the process fluid from bypassing the ice storage tanks <NUM> or from being provided to the heat exchanger <NUM>. A flow control device <NUM> may be in the flow enabled state to enable the process fluid to return to the chiller <NUM>. A flow control device <NUM> can be in a flow disabled state so that the process fluid is not provided to the AHU 14B. In an embodiment, the process fluid returned to the chiller <NUM> can be at a temperature T5. The temperature T5 can be from at or about <NUM> °F to at or about <NUM> °F. It will be appreciated that the range is intended to be exemplary and that the actual temperatures may vary beyond the stated range. In an embodiment, the pumps 50A, 50B may be disabled in the operating mode of <FIG>.

<FIG> represents an operating condition in which the chiller <NUM> can be used to make ice for the ice storage tanks <NUM> and to provide sensible cooling via the terminals 14A, according to an embodiment. The operating mode shown in <FIG> may generally be an operating mode in which ice can be made for later use (similar to <FIG>), as well as cooling provided to the terminals 14A. Such an operating mode may be used when, for example, the building is unoccupied but there is a cooling demand. The operating mode in <FIG> can be referred to as a nighttime operating mode.

The illustrated embodiment is similar to the embodiment shown and described relative to <FIG>. In <FIG>, the process fluid flow is enabled to the heat exchanger <NUM> such that the heat exchange can occur between the process fluid in the chiller circuit 12A and the process fluid in the terminal cooling circuit <NUM>. As a result, the process fluid provided to the terminals 14A can be at the temperature T2. In <FIG>, the process fluid can be provided from the chiller <NUM> at the temperature T4. The process fluid leaving the ice storage tanks <NUM> and being provided to the heat exchanger <NUM> can be at the temperature T5. The process fluid in the chiller circuit 12A can exchange heat with the process fluid in the terminal cooling circuit <NUM> via the heat exchanger <NUM> such that the process fluid in the terminal cooling circuit <NUM> is at the temperature T2. The process fluid can be returned to the chiller <NUM> at a temperature that is greater than the temperature T5 as a result of the heat exchange at the heat exchanger <NUM>.

<FIG> represents an operating condition in which the chiller <NUM> can be used to make ice for the ice storage tanks <NUM> and for dehumidification using the heat exchanger <NUM>, according to an embodiment. The operating mode shown in <FIG> may generally be an operating mode in which ice can be made for later use, as well as dehumidification provided via the optional heat exchanger <NUM>. Thus, for the embodiment 2E to be practiced, the chiller circuit 12A should include the heat exchanger <NUM>. Such an operating mode may be used when, for example, the building of the HVACR system <NUM> is unoccupied but there is a need to reduce humidity. The operating mode in <FIG> can also be referred to as a nighttime operating mode.

The illustrated embodiment is similar to the embodiment shown and described relative to <FIG>. In <FIG>, the process fluid flow can be enabled to the heat exchanger <NUM>. The pumps 50A, 50B may be disabled in the illustrated embodiment. The process fluid leaving the ice storage tanks <NUM> can be at the temperature T5. The process fluid can then be provided to the heat exchanger <NUM>, and can be returned to the chiller <NUM> at a temperature that is greater than the temperature T5.

<FIG> represents an operating condition in which the chiller <NUM> can be used to make ice for the ice storage tanks <NUM>, provide sensible cooling via the terminals 14A, and dehumidification via the heat exchanger <NUM>. The operating mode shown in <FIG> can also be referred to as a nighttime operating mode.

The illustrated embodiment is similar to the embodiments described in <FIG> and <FIG>. The embodiment of <FIG> can be a combination of the embodiments described in <FIG> and <FIG>. In the embodiment of <FIG>, the process fluid can be provided from the chiller <NUM> at the temperature T4. The process fluid leaves the ice storage tanks <NUM> and can be provided to the chiller circuit 12A at the temperature T5. The process fluid can then be used to transfer heat via the heat exchangers <NUM> and <NUM>. Similar to the embodiment in <FIG>, the optional heat exchanger <NUM> is included for the embodiment in <FIG>. Because of the heat exchange via the heat exchanger <NUM>, the process fluid in the terminal cooling circuit <NUM> can be provided at the temperature T2 to the terminals 14A. The process fluid in the chiller circuit 12A can be returned to the chiller <NUM> at a temperature that is greater than the temperature T5.

<FIG> is a schematic diagram of an HVACR system <NUM> that includes a chiller plant <NUM> and other components of the HVACR system <NUM>, according to an embodiment. Aspects of <FIG> can be the same as or similar to aspects of <FIG>. The other components of the HVACR system <NUM> can include, for example, various terminal devices/systems including, but not limited to, a sensible cooling variable air volume (VAV) terminal 14A and/or an air handling unit (AHU) 14B.

In the illustrated embodiment, three terminals 14A are shown. It will be appreciated that the number of terminals 14A is illustrative and can vary based on, for example, a building in which the HVACR system <NUM> is implemented.

In an embodiment, the chiller plant <NUM> includes a chiller <NUM>. The chiller <NUM> can be configured to provide a process fluid (e.g., a mixture of water and glycol, etc.) at the temperature T2. The temperature T2 can vary according to an operating mode of the chiller <NUM>. An operating mode can include a configuration selected to control the chiller <NUM> and its outputs to accomplish a particular environmental control goal (e.g., sensible cooling or dehumidification) or to make ice for the ice storage tanks <NUM>. For example, the operating mode can be selected to provide sensible cooling and/or dehumidification to the building. <FIG>, described in further detail below, show configurations of the HVACR system <NUM> according to various operating modes.

The chiller plant <NUM> includes a chiller circuit 112A and an air handling circuit 112B. In contrast to the embodiment in <FIG>, the HVACR system <NUM> does not include the terminal cooling circuit <NUM>. The chiller circuit 112A includes a process fluid circuit that generally includes a system or fluid circuit that may include, as appropriate, pipes, lines, pumps, valves, etc., that are configured to direct a process fluid conditioned by the chiller <NUM> to the terminals 14A. The air handling circuit 112B includes a process fluid circuit that generally includes a system or fluid circuit that may include, as appropriate, pipes, lines, pumps, valves, etc., that are configured to direct a process fluid to the AHU 14B.

The chiller circuit 112A generally includes the chiller <NUM>; flow control devices <NUM>, <NUM>; a plurality of pumps 50A, 50B; a heat exchanger <NUM>; terminals 14A; and a plurality of pumps 34A, 34B, fluidly connected. The pumps 34A, 34B and the pumps 50A, 50B can be used to circulate the process fluid throughout the chiller circuit 12A. The chiller <NUM> is not intended to be limited to a particular chiller design. For example, the chiller <NUM> can be an air-cooled chiller, a water-cooled chiller, or the like. The chiller <NUM> includes a refrigerant circuit (not shown) that can be configured to output the process fluid (e.g., water and glycol) at the temperature T2. The heat exchanger <NUM> is illustrated within dashed lines because the heat exchanger <NUM> is optional. The heat exchanger <NUM> can be used for cooling (and in an embodiment, dehumidification as well) and can be the same as or similar to a heat exchanger of the AHU 14B. In an embodiment, including the heat exchanger <NUM> can reduce a cooling load on the heat exchanger of the AHU 14B. Reducing the cooling load on the heat exchanger of the AHU 14B can, in an embodiment, reduce a size and/or number of the ice storage tanks <NUM> included in the HVACR system <NUM>. In an embodiment, including the heat exchanger <NUM> can provide an increase in efficiency of the HVACR system <NUM> over an HVACR system <NUM> that does not include the heat exchanger <NUM>.

The chiller circuit 112A and the air handling circuit 112B are fluidly connectable. In the illustrated embodiment, the chiller circuit 112A and the air handling circuit 112B are fluidly separated by, for example, preventing flow of the process fluid between the circuits 112A, 112B. The flow can be controlled using flow control devices <NUM>, <NUM>, and <NUM>. The flow control devices <NUM>, <NUM>, and <NUM> can be, for example, valves. In an embodiment, the flow control devices <NUM> and <NUM> can be two-way valves having a flow enabled state and a flow disabled state. The flow control device <NUM> can be a three-way flow control device that includes a flow enabled state and a flow disabled state for the three connections. In the illustrated embodiment, the flow control devices <NUM> and <NUM> are in the flow disabled state and the flow control device <NUM> is in a flow enabled state within the air handling circuit 112B and a flow disabled state for a connection between the air handling circuit 112B and a location that is downstream of the heat exchanger <NUM> in the chiller circuit 112A. In these states, the chiller circuit 112A and the air handling circuit 112B are fluidly separated.

In the illustrated embodiment, the terminals 14A can be provided with the same process fluid as is used by the chiller <NUM>. For example, the chiller <NUM> and the terminals 14A can both use a process fluid that includes a mixture of water and glycol.

The air handling circuit 112B includes ice storage tanks <NUM> fluidly connected with the AHU 14B and a plurality of pumps 40A, 40B. The plurality of pumps 40A, 40B can be used for circulating the process fluid throughout the air handling circuit 112B. In the illustrated embodiment, two ice storage tanks <NUM> are shown. It will be appreciated that the number of ice storage tanks <NUM> can vary. That is, in an embodiment, there can be a single ice storage tank <NUM>. In an embodiment, there can be more than two ice storage tanks <NUM>. For example, the number of ice storage tanks <NUM> can be based on cooling requirements of the building for which the HVACR system <NUM> is being used. The air handling circuit 112B generally includes a same process fluid as the process fluid used by the chiller <NUM>. That is, if the chiller <NUM> includes a process fluid that is a combination of water and glycol, then the air handling circuit 112B includes a process fluid that is a combination of water and glycol.

In the illustrated embodiment, the chiller <NUM> can generally provide the process fluid at the temperature T2. The air handling circuit 112B can use melting of the ice in the ice storage tanks <NUM> to provide the process fluid at a temperature T3 to the AHU 14B. The operating mode shown in <FIG> may be representative of an operating mode in which the building of the HVACR system <NUM> is occupied. In an embodiment, the occupied operating condition may be generally referred to as a daytime operating mode.

In the illustrated embodiment, the process fluid provided from the chiller <NUM> may be provided at a temperature that is greater than the temperature T2. In an embodiment, operating the chiller <NUM> to provide the relatively warmer process fluid may, for example, reduce an amount of energy consumed by the chiller <NUM>. In the illustrated embodiment, the flow control devices <NUM> and <NUM> are in the flow enabled state. Accordingly, the chiller circuit 112A and the air handling circuit 112B are fluidly connected. Because of the fluid connection, ice that is melting from the ice storage tanks <NUM> and is at a temperature lower than T2 can be mixed with the process fluid from the chiller <NUM>. As a result, the process fluid can leave the chiller <NUM> at a temperature that is greater than T2, but be cooled to the temperature T2 at a location that is upstream of the terminals 14A. As a result, the process fluid provided to the terminals 14A can be provided at the temperature T2, even when the chiller <NUM> is outputting the process fluid at a temperature that is greater than the temperature T2. In the illustrated embodiment, the ice is melting from the ice storage tanks <NUM> and can be used to provide the process fluid of the outdoor air handling circuit 112B to the AHU 14B at the temperature T3.

In the illustrated embodiment, the process fluid provided from the chiller <NUM> may be provided at the temperature T3. In the illustrated embodiment, the flow control device <NUM> can be in the flow disabled state. The flow control device <NUM> can be in the flow enabled state. The flow control device <NUM> can be in a state in which flow is disabled between the chiller <NUM> and the flow control device <NUM>. The flow control device <NUM> can be in a state in which flow is enabled between the AHU 14B and the flow control device <NUM>. The flow control device <NUM> can be in the flow enabled state between the flow control device <NUM> and a location of the chiller circuit 112A that is downstream of the heat exchanger <NUM>. The state of the flow control devices <NUM>, <NUM>, and <NUM>, enables fluid communication between the chiller circuit 112A and the air handling circuit 112B. However, the ice storage tanks <NUM> are fluidly separated from the air handling circuit 112B by placing a flow control device <NUM> in a flow disabled state. In such an embodiment, the ice storage tanks <NUM> may, for example, be empty or have an insufficient amount of ice to provide the process fluid at the temperature T3. The chiller <NUM> can provide the process fluid at the temperature T3. In the illustrated embodiment, the process fluid can be provided to the AHU 14B at the temperature T3. A flow control device <NUM> can enable some mixing of the process fluid at the temperature T3 can with warmer process fluid via the pumps 50A, 50B so that the process fluid is provided to the terminals 14A at the temperature T2. The diverted state of the flow control device <NUM> returns the process fluid to a location that is downstream of the heat exchanger <NUM>.

In the illustrated embodiment, the process fluid can be provided from the chiller <NUM> at the temperature T4. In the illustrated embodiment, the flow control device <NUM> and the flow control device <NUM> may be in the flow enabled state. A flow control device <NUM> may be in a flow disabled state to prevent the process fluid from bypassing the ice storage tanks <NUM>. A flow control device <NUM> can be in a flow disabled state so that the process fluid is not provided to the AHU 14B. In an embodiment, the process fluid returned to the chiller <NUM> can be at a temperature T5.

The illustrated embodiment is similar to the embodiment shown and described relative to <FIG>. In <FIG>, the process fluid flow is enabled to the terminals 14A. In <FIG>, the process fluid can be provided from the chiller <NUM> at the temperature T4. The process fluid leaving the ice storage tanks <NUM> is at the temperature T5. Flow control device <NUM> can enable mixing of some of this fluid at temperature T5 with fluid returning from the terminals 14A so that the resulting mixed fluid being provided to the terminals 14A can be at the temperature T2. The process fluid can be returned to the chiller <NUM> at a temperature that is greater than the temperature T5.

<FIG> represents an operating condition in which the chiller <NUM> can be used to make ice for the ice storage tanks <NUM> and for dehumidification using the AHU 14B, according to an embodiment. The operating mode shown in <FIG> may generally be an operating mode in which ice can be made for later use, as well as dehumidification provided via the AHU 14B. Such an operating mode may be used when, for example, the building of the HVACR system <NUM> is unoccupied but there is a need to reduce humidity. The operating mode in <FIG> can also be referred to as a nighttime operating mode.

The illustrated embodiment is similar to the embodiment shown and described relative to <FIG>. The process fluid leaving the ice storage tanks <NUM> can be at the temperature T5. The process fluid can then be provided to the AHU 14B, and can be returned to the chiller <NUM> at a temperature that is greater than the temperature T5.

<FIG> represents an operating condition in which the chiller <NUM> can be used to make ice for the ice storage tanks <NUM>, provide sensible cooling via the terminals 14A, and dehumidification via the AHU 14B. The operating mode shown in <FIG> can also be referred to as a nighttime operating mode.

The illustrated embodiment is similar to the embodiments described in <FIG> and <FIG>. The embodiment of <FIG> can be a combination of the embodiments described in <FIG> and <FIG>. In the embodiment of <FIG>, the process fluid can be provided from the chiller <NUM> at the temperature T4. The process fluid leaves the ice storage tanks <NUM> and can be provided to the chiller circuit 12A at the temperature T5. The process fluid can then be used to provide sensible cooling via the terminals 14A and dehumidification via the AHU 14B. The process fluid in the chiller circuit 12A can be returned to the chiller <NUM> at a temperature that is greater than the temperature T5.

<FIG> are schematic diagrams of HVACR systems 200A, 200B including a free cooling option. In <FIG>, the free cooling option includes a separate dry cooler <NUM> that is separate from the chiller <NUM>. In <FIG>, the free cooling option is incorporated into the chiller <NUM>. The embodiment in <FIG> may generally be the same as the embodiment in <FIG>. The embodiment in <FIG> is modified to include the dry cooler <NUM>. It will be appreciated that the embodiment in <FIG> can similarly include a free cooling option.

<FIG> is a schematic diagram of a refrigerant circuit <NUM>, according to an embodiment. The refrigerant circuit <NUM> generally includes a compressor <NUM>, a condenser <NUM>, an expansion device <NUM>, and an evaporator <NUM>. The compressor <NUM> can be, for example, a scroll compressor, a screw compressor, a centrifugal compressor, or the like. The refrigerant circuit <NUM> is an example and can be modified to include additional components. For example, in an embodiment, the refrigerant circuit <NUM> can include other components such as, but not limited to, an economizer heat exchanger, one or more flow control devices, a receiver tank, a dryer, a suction-liquid heat exchanger, or the like.

The refrigerant circuit <NUM> can generally be applied in a variety of systems used to control an environmental condition (e.g., temperature, humidity, air quality, or the like) in a space (generally referred to as a conditioned space). Examples of such systems include, but are not limited to, HVACR systems or the like.

The compressor <NUM>, condenser <NUM>, expansion device <NUM>, and evaporator <NUM> are fluidly connected.

The refrigerant circuit <NUM> can operate according to generally known principles. The refrigerant circuit <NUM> can be configured to heat or cool a liquid process fluid (e.g., a heat transfer fluid or medium such as, but not limited to, water, glycol, combinations thereof, or the like), in which case the refrigerant circuit <NUM> may be generally representative of a liquid chiller system. For example, the refrigerant circuit <NUM> may be implemented in the chiller <NUM> shown and described above in accordance with <FIG> above. Furthermore, the refrigerant circuit <NUM> and corresponding chiller (e.g., chiller <NUM>) can be connected in parallel to condition the process fluid.

In operation, the compressor <NUM> compresses a working fluid (e.g., a heat transfer fluid such as a refrigerant or the like) from a relatively lower pressure gas to a relatively higher-pressure gas. The relatively higher-pressure gas is also at a relatively higher temperature, which is discharged from the compressor <NUM> and flows through the condenser <NUM>. The working fluid flows through the condenser <NUM> and rejects heat to a process fluid (e.g., water, glycol, combinations thereof, or the like), thereby cooling the working fluid. The cooled working fluid, which is now in a liquid form, flows to the expansion device <NUM>. The expansion device <NUM> reduces the pressure of the working fluid. As a result, a portion of the working fluid is converted to a gaseous form. The working fluid, which is now in a mixed liquid and gaseous form flows to the evaporator <NUM>. The working fluid flows through the evaporator <NUM> and absorbs heat from a process fluid (e.g., water, glycol, combinations thereof, or the like), heating the working fluid, and converting it to a gaseous form. The gaseous working fluid then returns to the compressor <NUM>. The above-described process continues while the refrigerant circuit is operating, for example, in a cooling mode (e.g., while the compressor <NUM> is enabled).

<FIG> is a schematic diagram of a method <NUM> for controlling a chiller plant (e.g., the HVACR systems <NUM>, <NUM>, and 200A/200B of <FIG>), according to an embodiment. The method <NUM> is generally representative of a control method that includes receiving information indicative of operating conditions in a building having the chiller plant, making an operating mode determination, and controlling the various components of the chiller plant to achieve the desired operating conditions.

At <NUM>, a plurality of operating factor inputs are received by a controller. The controller can include a processor, a memory, a clock, and an input/output (I/O) interface. In an embodiment, the controller can include fewer or additional components. The controller can receive the operating factor inputs from a plurality of sensors. The operating factor inputs can include, for example, a time of day schedule, a cold water load, a cool water load, a chiller failure status, an ice inventory status, or the like. It will be appreciated that additional inputs may be received at <NUM>.

At <NUM>, the controller utilizes the plurality of operating factor inputs to determine an operating mode of the chiller plant and a setpoint for the chiller plant. The controller may make separate decisions for the operating mode and the setpoint. For example, the operating mode determination may be made prior to making the setpoint determination, and the operating mode determination may be an input to the setpoint determination.

The various operating modes can include, for example, an "Off" mode; a mode in which the chiller circuit (e.g., chiller circuit 12A) and the air handling ciruit (e.g., the air handling circuit 12B) operate separately (e.g., <FIG>); a mode in which the chiller circuit (e.g., chiller circuit 12A) and the air handling ciruit (e.g., the air handling circuit 12B) operate together (e.g., <FIG>); a mode in which the chiller circuit (e.g., chiller circuit 12A) is operating and the air handling circuit (e.g., air handling circuit 12B) is not operating (e.g., <FIG>); a mode in which the air handling circuit (e.g., the air handling circuit 12B) is operating but the chiller is not operating (e.g., <FIG> when the chiller is not operating); a mode in which ice is being made (e.g., <FIG>); a mode in which ice is being made and sensible cooling is enabled (e.g., <FIG> when the chiller is operating); a mode in which ice is being made and dehumidification is being performed (e.g., <FIG>); and a mode in which ice is being made, sensible cooling is enabled, and dehumidification is being performed (e.g., <FIG>). Each of the operating modes correspond to particular settings for the components of the chiller plant. The setpoint determination corresponds to an ice plant setpoint, a chiller setpoint, valve controls, pump speeds, and a chiller demand limit setpoint.

At <NUM>, the controller communicates with the various components in the chiller plant to place the chiller plant in the corresponding mode with settings selected for the particular setpoint. For example, in the operating mode of <FIG> (e.g., chiller circuit 12A and air handling circuit 12B operating separately), the settings can include disabling flow through flow control device <NUM>, enabling flow through flow control device <NUM>, disabling flow through flow control device <NUM>, etc..

Examples of operating modes for a chiller plant and corresponding settings that may be implemented using the above systems and the method <NUM> can include those identified in the following Tables 1A and 1B. It will be appreciated that the operating modes in Tables 1A and 1B can vary. For example, a chiller plant may not include all operating modes of Tables 1A and 1B. In an embodiment, a chiller plant may include more operating modes than included in Tables 1A and 1B. It will be appreciated that certain operating specifics (e.g., temperature set points, etc.) in the following tables may vary according to the implementation.

The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. The terms "a," "an," and "the" include the plural forms as well, unless clearly indicated otherwise. The terms "comprises" and/or "comprising," when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.

Claim 1:
A chiller plant (<NUM>, <NUM>), comprising:
a chiller circuit (12A, 112A) including a chiller (<NUM>) and a process fluid circuit, the chiller being configured to provide a process fluid at a first temperature; and
an air handling circuit (12B, 112B) including a plurality of ice storage tanks (<NUM>) and an air handling unit (14B),
characterized in that the chiller circuit (12A, 112A) and the air handling circuit (12B, 112B) are fluidly connectable such that the chiller (<NUM>) is used to create ice for the plurality of ice storage tanks (<NUM>);
wherein the chiller plant comprises flow control devices (<NUM>, <NUM>, <NUM>) each configured to move between a flow disabled state and a flow enabled state, for fluidly separating and fluidly connecting the chiller circuit (12A, 112A) and the air handling circuit (12B, 112B).