US20250347429A1

US20250347429A1 - Baseline electrical load operation for a climate control system of a commercial building

Info

Publication number: US20250347429A1
Application number: US18/658,612
Authority: US
Inventors: Michael Sean Day
Original assignee: Trane International Inc
Current assignee: Trane International Inc
Priority date: 2024-05-08
Filing date: 2024-05-08
Publication date: 2025-11-13
Also published as: DE202025102324U1

Abstract

An embodiment of a climate control system for conditioning an interior space includes an interior space heat exchange circuit that is configured to circulate a working fluid to cool an airflow that is directed to the interior space. In addition, the climate control system includes a chiller that is configured to cool the working fluid. Further, the climate control system includes a thermal energy storage (TES) assembly further including a source of low-temperature fluid and a heat exchanger that is coupled to the interior space heat exchange circuit such that the heat exchanger is upstream of the chiller along the interior space heat exchange circuit. The heat exchanger is configured to receive a flow of the low-temperature fluid from the source to cool the working fluid to thereby supplement an output cooling capacity of the chiller.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

BACKGROUND

Commercial buildings, such as office buildings, retail stores, data centers, or others, may draw large amounts of electrical power from a local utility grid. Thus, building owners and/or operators (collectively referred to herein as “building operators”) are often keen to reduce a total electrical load of the building so as to reduce operating costs. Indoor climate control is typically a major component (if not the largest component) of a commercial building's total electrical load requirements. Thus, the design and operation of a building's climate control system may be a major contributing factor to reducing that building's electrical footprint.

BRIEF SUMMARY

Some embodiments disclosed herein are directed to a climate control system for conditioning an interior space. In some embodiments, the climate control system includes an interior space heat exchange circuit that is configured to circulate a working fluid to cool an airflow that is directed to the interior space. In addition, the climate control system includes a chiller that is configured to cool the working fluid. Further, the climate control system includes a thermal energy storage (TES) assembly further including a source of low-temperature fluid and a heat exchanger that is coupled to the interior space heat exchange circuit such that the heat exchanger is upstream of the chiller along the interior space heat exchange circuit. The heat exchanger is configured to receive a flow of the low-temperature fluid from the source to cool the working fluid to thereby supplement an output cooling capacity of the chiller.
In some embodiments, the climate control system includes an interior space heat exchange circuit that is configured to circulate a working fluid to cool an airflow that is directed to the interior space. In addition, the climate control system includes a plurality of chillers that are configured to cool the working fluid. Further, the climate control system includes a thermal energy storage (TES) assembly that is thermally coupled to the interior space heat exchange circuit via a plurality of heat exchangers that are arranged along the interior space heat exchange circuit. Still further, the climate control system includes a controller communicatively coupled to the plurality of chillers and the TES assembly. The controller is configured to adjust an output cooling capacity of the plurality of chillers and to adjust a distribution of cooling capacity from the TES assembly to maintain an electrical load of the climate control system at or below a baseline electrical load.
Some embodiments disclosed herein are directed to a method of operating a climate control system for a building. In some embodiments, the method includes (a) receiving weather data for an upcoming day for a geographic area in which the building is located. In addition, the method includes (b) determining a total cooling capacity available from a thermal energy storage (TES) assembly of the climate control system. Further, the method includes (c) determining a baseline electrical load to operate the climate control system based at least on the weather data and the total cooling capacity available from the TES assembly. Still further, the method includes (d) determining an output cooling capacity of a plurality of chillers of the climate control system and a distribution of cooling capacity from the TES assembly that is configured to satisfy a cooling demand of the building at an electrical load of the climate control system that is at or below the baseline electrical load.
Embodiments described herein comprise a combination of features and characteristics intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical characteristics of the disclosed embodiments in order that the detailed description that follows may be better understood. The various characteristics and features described above, as well as others, will be readily apparent to those having ordinary skill in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated that this disclosure may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes as the disclosed embodiments. It should also be realized that such equivalent constructions do not depart from the spirit and scope of the principles disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of various embodiments, reference will now be made to the accompanying drawings in which:

FIG. 1 is a schematic drawing of a climate control system including a thermal energy storage assembly according to some embodiments disclosed herein;

FIG. 2 is a schematic diagram of a chiller of the climate control system of FIG. 1 according to some embodiments disclosed herein;

FIG. 3 is a chart showing the electrical load drawn by one of the chillers of the climate control system of FIG. 1 based on output cooling capacity and outdoor ambient temperature according to some embodiments disclosed herein;

FIG. 4 is a plot showing example electrical loads drawn by the climate control system of FIG. 1 per unit time during a peak period of an example day according to some embodiments disclosed herein;

FIG. 5 is a schematic drawing of a climate control system including a thermal energy storage assembly according to some embodiments disclosed herein;

FIG. 6 is a plot showing example electrical loads drawn by the climate control system of FIG. 5 per unit time during an example day according to some embodiments disclosed herein; and

FIG. 7 is a flow chart of a method of operating a climate control system for a building according to embodiments disclosed herein.

DETAILED DESCRIPTION

The climate control system of a commercial building may be a major (or even the largest) component of the building's electrical load. Thus, the design and operation of a building's climate control system may have a major effect on the total electrical load requirements for the building. In addition, the electrical load requirements of a climate control system may vary substantially during a twenty-four-hour period, and may generally resemble a sinusoidal curve with a maximum or peak load (for cooling) typically occurring sometime in the late afternoon and a minimum load (again, for cooling) typically occurring in the early morning hours. A building operator must therefore reserve a sufficient electrical load capacity to operate the climate control system during the peak loading period. However, this results in a substantial amount of unused reserved electrical load capacity during the other periods of the day, that could otherwise be monetized (e.g., via sold electrical load capacity to one or more of the tenants or users of the commercial building). Moreover, a building operator may reserve sufficient electrical load capacity in order to operate the climate control system during a worst-case peak temperature over a historical period (e.g., such as twenty years in some cases). As a result, on an average day (when the maximum or peak temperatures are substantially lower than the worst-case peak temperature) the unused and reserved electrical load capacity for the climate control system is even larger.
Accordingly, embodiments disclosed herein include systems and methods for designing and operating a climate control system that are aimed at unlocking this un-used electrical load capacity so that it may be monetized or otherwise used by the building operator. For instance, embodiments of the system and methods disclosed herein may be configured to substantially flatten the electrical load requirements for the climate control system over a twenty-four-hour period, to thereby unlock the electrical load typically reserved for peak periods. Thus, by use of the embodiments disclosed herein, a building operator may reduce the total electrical load that must be reserved for operation of the building's climate control system, and this additional electrical load capacity may be further monetized or used for other purposes.
Referring now to FIG. 1 , a climate control system 10 including a thermal energy storage (TES) assembly 60 (or more simply “TES” 60) is shown according to some embodiments disclosed herein. The climate control system 10 may be configured to cool one or more interior spaces of a commercial building 12 (or more simply “building” 12) during operations. Specifically, the climate control system 10 may include one or more (e.g., one or a plurality of) chillers 15 that are configured to cool a working fluid 54 that is circulating along an interior space heat exchange circuit 50 between the chillers 15 and a interior space heat exchange assembly 52. The chillers 15 may be arranged in parallel along the interior space heat exchange circuit 50; however, other arrangements are contemplated. The working fluid 54 may comprise water or a suitable aqueous mixture (e.g., water-glycol). In some embodiments, the working fluid 54 may comprise a fluid other than water, such as, for instance air (e.g., air that is directly provided to the conditioned space). The conditioned space heat exchange assembly 52 may comprise one or more heat exchangers (e.g., air handler units) that are configured to exchange heat between the working fluid 54 and an airflow that is provided to the interior space(s) inside the building 12.
Each of the chillers 15 may be configured to cool the working fluid 54 via one or more refrigeration circuits. For instance, reference is now made to FIG. 2 which shows a general schematic of one of the chillers 15 of FIG. 1 according to some embodiments (it being appreciated that each of the other chillers 15 in FIG. 1 may be configured the same or similarly to that shown in FIG. 2 in some embodiments).
Generally speaking, each chiller 15 includes a refrigeration circuit 20 that is configured to circulate a refrigerant to exchange heat between the interior space(s) of the building 12 and an ambient environment (e.g., such as the outdoor environment that surrounds the building 12), so as to cool the interior space(s). The refrigeration circuit may include a first heat exchanger 22 and a second heat exchanger 24. The first heat exchanger 22 is configured to exchange heat between the refrigerant and a working fluid 44 of an ambient heat exchange circuit 40, and the second heat exchanger 24 is configured to exchange heat between the refrigerant and the working fluid 54 of the interior space heat exchange circuit 50.
The working fluid 44 may comprise water or any other suitable aqueous mixture such as previously described above for the working fluid 54. Alternatively, the working fluid 44 may comprise air. When the working fluid 44 is water, the chiller 15 may be referred to as a “water-cooled” chiller, and when the working fluid is air, the chiller 15 may be referred to as an “air-cooled” chiller unit. Regardless, the working fluid 44 may circulate between the first heat exchanger 22 of the refrigeration assembly 20 and an ambient heat exchange assembly 42 to exchange heat between the refrigerant and the ambient environment. In some embodiments, the ambient heat exchange assembly 42 comprises one or more heat exchangers (e.g., water cooling towers, radiators, fin-fan coolers, etc.) that are configured to transfer heat between the ambient environment and the working fluid 44. In some embodiments, such as in the case of air-cooled chillers, the ambient heat exchange assembly 42 may be integrated and combined with the first heat exchanger 22 so that heat is directly exchanged between the refrigerant and an airflow that is sourced from and provided back to the ambient environment. In addition, in some embodiments, such as in the case of water-cooled chillers, the ambient heat exchange assembly 42 may be shared and integrated across each of the chillers 15 of the climate control system 10 (e.g., so that the first heat exchangers 22 of each of the chillers 15 are fluidly coupled in parallel along a common ambient heat exchange circuit 40).
In addition to the first heat exchanger 22 and the second heat exchanger 24, the refrigeration circuit 20 may include a compressor 26 (or one or more compressors 26 in some embodiments) and an expansion valve 30. The compressor 26 and expansion valve 30 may be in fluid communication with the first heat exchanger 22 and second heat exchanger 24 along the refrigerant circuit 20. During operations, the refrigeration circuit 20 may be operated to circulate the refrigerant in a first direction shown in FIG. 2 so as to transfer heat from the interior space (e.g., via the interior space heat exchange circuit 50) to the ambient environment (e.g., via the ambient environment heat exchange circuit 40). Such operation may be referred to herein as a “cooling mode” operation.
Specifically, in the cooling mode operation shown in FIG. 2 , the refrigerant (which may be in a vapor or semi-vapor state) may be compressed by the compressor 26 and delivered to the first heat exchanger 22 via the refrigerant circuit 20. Within the first heat exchanger 22, heat is transferred from the refrigerant to the working fluid 44, which cools the refrigerant and at least partially condenses the refrigerant to a liquid. Thus, in the cooling mode operation of FIG. 2 , the first heat exchanger 22 may be referred to as a “condenser.” Heat is then transferred from the heated working fluid 44 to the ambient environment via the ambient heat exchange assembly 42 of the ambient heat exchange circuit 40 as previously described.
The condensed refrigerant is then expelled from the first heat exchanger 22 and flowed to the second heat exchanger 24 via the expansion valve 30. The expansion valve 30 may be positioned between the first heat exchanger 22 and second heat exchanger 24 along the refrigerant circuit 20. The expansion valve 30 may be actuated so as to controllably expand and therefore cool the refrigerant upstream of the second heat exchanger 24.
The expanded and cooled refrigerant is then flowed to the second heat exchanger 24. Within the second heat exchanger 24, heat is transferred from the working fluid 54 to the refrigerant, which vaporizes (or at least partially vaporizes) the refrigerant. Thus, in the cooling mode operation of FIG. 1 , the second heat exchanger 24 may be referred to as an “evaporator.” The cooled working fluid 54 is then used to cool the interior space(s) of building 12 via the conditioned space heat exchange assembly 52 of the interior space heat exchange circuit 50 as previously described.
While not shown, in some embodiments, the refrigeration circuit 20 may circulate the refrigerant in a second, opposite direction than that shown in FIG. 2 so as to transfer heat from the ambient environment to the interior space(s) of building 12 via the ambient heat exchange circuit 40 and the interior space heat exchange circuit 50. Such operation may be referred to herein as a “heating mode” operation, and a refrigeration assembly 20 that is configured to operate in the heating mode may be referred to as a “heat pump.” During a heating mode operation of the refrigeration circuit 20, the first heat exchanger 22 may function as an “evaporator” (which vaporizes the refrigerant) and the second heat exchanger 24 may function as a “condenser” (which condenses the refrigerant).
The operation of the chiller 15 may be adjusted so as to provide different output cooling (or heating) capacities to the working fluid 54 during operations. Specifically, the mass flow rate of refrigerant flowing along the refrigerant circuit 20 may be adjusted (e.g., via adjustments to the operating speed of the compressor 26 and corresponding adjustments to the opening position of the expansion valve 30) to thereby change the rate of thermal heat transfer between the refrigerant and the working fluid 54 during operations. In some embodiments, the chiller 15 may be operated at a lower output cooling capacity (e.g., by lowering the speed of the compressor 26) when the cooling demands of the interior space(s) of building 12 are lower-such as during non-peak times.
Referring again to FIG. 1 , the TES 60 is configured to supplement the output cooling capacity of the chillers 15 via heat transfer with the working fluid 54 via one or more (e.g., one or a plurality of) heat exchangers 62. In particular, the TES 60 may be configured to provide a low-temperature fluid 64 to the heat exchangers 62 so as to perform additional heat exchange with the working fluid 54 of the interior space heat exchange circuit 50 to thereby reduce a cooling demand on the chillers 15 during operations.
The heat exchangers 62 may each be positioned upstream of the chillers 15 so that the heat exchangers 62 may be arranged in parallel along the interior space heat exchange circuit 50. Specifically, each heat exchanger 62 may be positioned upstream of a corresponding one of the chillers 15 so that the working fluid 54 may first flow through one of the heat exchangers 62 before flowing through the corresponding chiller 15 during operations, and the number of heat exchangers 62 may be equal to (or potentially less than) the number of chillers 15. In addition, a plurality of valves 66 may be positioned between the TES 60 and the heat exchangers 62 that may selectively control the flow of the low-temperature fluid 64 from the TES 60 to each of the heat exchangers 62 during operations. In addition, one or more pumps or other pressurization devices (not specifically shown) may be utilized to facilitate the flow of the low-temperature fluid 64 to the heat exchangers 62 via the valves 66 during operations.
The low-temperature fluid 64 may comprise water or a suitable aqueous mixture (e.g., water-glycol). In some embodiments, the low-temperature fluid 64 may comprise a fluid other than water, such as, for instance air. The low-temperature fluid 64 is referred to as “low-temperature” in that the temperature of the fluid 64 may be low enough to facilitate heat transfer from the working fluid 54 to the low-temperature fluid 64 via the heat exchangers 62.
During operations, the TES 60 may deliver additional cooling (or heating) to the working fluid 54 via the low-temperature fluid 64 and heat exchangers 62 so as to reduce a total electrical load drawn by the chillers 15. The TES 60 may comprise any device or system that is configured to store additional heating or cooling capacity that may be selectively delivered to the working fluid 54, via low-temperature fluid 64 and heat exchangers 62, during operations. For instance, in some embodiments, the TES 60 may comprise cold water tank(s), volumes of phase-change materials (e.g., ice, wax, etc.) or other thermally absorbent materials, source(s) of cool/warm fluid such as water-cooling towers that circulate captured rainwater, geothermal wells, liquid nitrogen (N₂), or liquid carbon dioxide (CO₂).
In some embodiments, valves 66 may be actuated to selectively provide the low-temperature fluid 64 to select ones of the heat exchangers 62 so as to provide targeted supplemental heat exchange to the working fluid 54 and thereby efficiently and effectively reduce a total electrical load drawn by the climate control system 10 while avoiding reductions in the cooling capacity delivered thereby during operations. Specifically, during operations, a controller 120 may be used to selectively adjust an operating level of each of the chillers 15 and, in concert, may adjust distribution of low-temperature fluid 64 to the heat exchangers 62 so as to provide a desired cooling capacity to the interior space(s) of the building 12 via interior space heat exchange circuit 50 while achieving and maintaining a substantially optimized electrical performance of the climate control system 10. These adjustments by the controller 120 may have the effect of flattening the overall electrical demand of the climate control system 10 over a period of time (e.g., such as a twenty-four-hour period) so that the building owner may free up additional electrical capacity for the building 12 (which may be monetized or more efficiently utilized elsewhere as noted herein).
The controller 120 may be (or may be incorporated within) a main or master controller for the climate control system 10, or the controller 120 may be a standalone controller 120 for controlling the operational level(s) of the chillers 15 and/or the distribution of the low-temperature fluid 64 to and from the TES 60 during operations. Regardless, the controller 120 may be described and referred to herein as being a part of the climate control system 10.
The controller 120 may comprise one or more computing devices, such as a computer, tablet, smartphone, server, circuit board, or other computing device(s) or system(s). Thus, controller 120 may include a processor 122 and a memory 124.
The processor 122 may include any suitable processing device or a collection of processing devices. In some embodiments, the processor 122 may include a microcontroller, central processing unit (CPU), graphics processing unit (GPU), timing controller (TCON), scaler unit, or some combination thereof. During operations, the processor 122 executes machine-readable instructions (such as machine-readable instructions 126) stored on memory 124, thereby causing the processor 122 to perform some or all of the actions attributed herein to the controller 120. In general, processor 122 fetches, decodes, and executes instructions (e.g., machine-readable instructions 126). In addition, processor 122 may also perform other actions, such as, making determinations, detecting conditions or values, etc., and communicating signals. If processor 122 assists another component in performing a function, then processor 122 may be said to cause the component to perform the function.
The memory 124 may be any suitable device or collection of devices for storing digital information including data and machine-readable instructions (such as machine-readable instructions 126). For instance, the memory 124 may include volatile storage (such as random-access memory (RAM)), non-volatile storage (e.g., flash storage, read-only memory (ROM), etc.), or combinations of both volatile and non-volatile storage. Data read or written by the processor 122 when executing machine-readable instructions 126 can also be stored on memory 124. Memory 124 may include “non-transitory machine-readable medium,” where the term “non-transitory” does not include or encompass transitory propagating signals.
The processor 122 may include one processing device or a plurality of processing devices that are distributed within (or communicatively coupled to) controller 120 or more broadly within climate control system 10. Likewise, the memory 124 may include one memory device or a plurality of memory devices that are distributed within (or communicatively coupled to) controller 120 or more broadly within climate control system 10. Thus, the controller 120 may comprise a plurality of individual “controllers” distributed throughout the climate control system 10.
As previously described, the controller 120 may be used to selectively adjust an operating level of each of the chillers 15 and, in concert, may adjust distribution of low-temperature fluid 64 to the heat exchangers 62 to as to provide a desired cooling capacity to the interior space(s) of the building 12 via working fluid 54 while achieving and maintaining a substantially optimized electrical load for the climate control system 10. In particular, as will be described in more detail herein, it has been discovered that each chiller 15 may have non-linearly varying efficiency along a range of operating levels at given outdoor ambient temperatures, so that simply uniformly reducing an operating level of the chillers 15 may not provide an optimal operating efficiency (in terms of electrical load) for the climate control system 10. Thus, the controller 120 may optimize electrical load utilization of the climate control system 10 by operating select combinations of the chillers 15 (e.g., one or more or all) at select operating levels while also distributing low-temperature fluid 64 from the TES 60, based on the non-linearly variable operating efficiency of the chillers 15 and the outdoor ambient temperatures for the environment surrounding building 12.
Referring now to FIG. 3 , a chart 32 showing the electrical load drawn by one of the chillers 15 of the climate control system 10 (FIG. 1 ) based on output cooling capacity and outdoor ambient temperature is shown according to some embodiments. The chart 32 may be representative of the electrical load drawn by a particular one of the chillers 15, and thus, each chiller 15 may include a similar (but unique) chart 32 that may be used by controller 120 to adjust an output cooling capacity of the chillers 15 and/or the distribution of low-temperature fluid 64 from the TES 60 (FIG. 1 ) during operations.
The output cooling capacity of chiller 15 associated with the chart 32 may comprise a total thermal energy transfer rate (e.g., in “Tons” which is British Thermal Units (BTU) per hour) that the chiller 15 may provide the working fluid 54 (FIG. 1 ) at a particular operational speed of the corresponding compressor 26 (FIG. 2 ). The output cooling capacity may be represented in the chart 32 as a percentage of the maximum output cooling capacity that may be delivered by the chiller 15. However, in some embodiments, the output cooling capacity of the chiller 15 associated with chart 32 may be represented in a different manner, such as directly in Tons (or other suitable units for a thermal energy transfer rate).
The outdoor ambient temperature may be a temperature of the outdoor environment surrounding the building 12. The range of 78° F. to 96° F. is shown in 2° increments in the chart 32 as an example; however, any suitable temperature range (and graduation) may be included. For instance, in some embodiments, the temperature range included in the chart 32 may be based on the typical range of temperatures that are experienced in the geographical area that the building 12 is located.
As indicated in the chart 32 of FIG. 3 , the chiller 15 may draw electrical loads of A10, B10, C10, . . . J10 (e.g., in kilowatts (KW)) when the chiller 15 is operated at 10%, 20%, 30%, . . . 100%, respectively, of maximum cooling capacity at 96° F. outdoor ambient temperature. The electrical loads A10, B10, C10, . . . J10 may generally increase along with the output cooling capacity of the chiller 15; however, the increase in the electrical loads A10, B10, C10, . . . J10 may not be linear. Thus, the difference between the electrical loads A10 and B10 may be different from the difference between the electrical loads B10 and C10, or between the electrical loads C10 and D10, and so on.
In addition, the operating efficiency for the chiller 15 associated with chart 32 (in terms of electrical power consumption) may be different at different output cooling capacities and outdoor ambient temperatures. In particular, the operating efficiency of the chiller 15 associated with the chart 32 can be represented as the units of electrical load (e.g., in KW or other suitable units) per Ton (or other suitable unit) of output cooling capacity provided by the chiller 15 using the chart 32. The changes in these operational efficiencies in the chart 32 for a particular outdoor ambient temperature may be non-linear due at least in part to the non-linear differences in electrical load drawn by the chiller at different output cooling capacities as previously described.
For example, in some embodiments the chiller 15 associated with the chart 32 may configured to provide a maximum of about 600 Tons of output cooling capacity (e.g., at 100% output cooling capacity in chart 32), and electrical load values J10, 110, and H10 may equal about 650 KW, 513 KW, and 473 KW, respectively. Thus, in this particular example, for the chiller 15 associated with chart 32, operating at 100% of maximum output cooling capacity may require about 1.084 KW of electrical load per Ton of cooling capacity, operating at 90% of maximum output cooling capacity may require about 0.949 KW of electrical load per Ton of cooling capacity, and operating at 80% of maximum output cooling capacity may require about 0.986 KW of electrical load per Ton of cooling capacity. These example differences in operating efficiency between the 100%, 90%, and 80% of output cooling capacity for the chiller 15 (in terms of KW of electrical load per Ton of output cooling capacity) are non-linear and even show an rather surprising increase between operation at 90% output cooling capacity (at about 0.949 KW/Ton) vs operation at 80% output cooling capacity (at about 0.986 KW/Ton), when one would typically expect the operational efficiency to decrease along with a decreasing output cooling capacity. Without being limited to this or any other theory, the source of these non-linearities of the chillers 15 is believed to stem from the various unique characteristics and variances of the chillers 15 (which can be derived from manufacturing tolerances, installation parameters, operating histories, or other factors).
Accordingly, during operation, the controller 120 may selectively operate combinations of the chillers 15 at different output cooling capacities based on the data included in the chart 32 associated with each chiller 15 so as to provide an optimal balance of cooling capacity per the electrical load drawn. Specifically, the controller 120 may be configured to determine a combination of chillers 15 operating to provide selected output cooling capacities so as to satisfy a desired cooling demand (which may be based on the outdoor ambient temperature) while minimizing the total KW of electrical load per Ton of output cooling capacity during operations. The use of the specific and unique data of chart 32 may allow the controller 120 to account for the non-linearly variable characteristics and performance of the chillers 15.
In some embodiments, the data (e.g., the electrical load data) in the chart 32 may be initially calculated based on one or more parameters of the chiller 15. However, as the climate control system 10 is operated, the values in the chart 32 may be replaced (e.g., by controller 120) with updated values that are based on actual performance of the chiller 15 as installed. Thus, over time, the controller 120 may adjust the operational parameters of chillers 15 based on their unique performance within the climate control system 10 over the range of outdoor ambient temperatures that the building 12 is exposed to. In some embodiments, the chart(s) 32 (or data indicative thereof) may be at least partially stored in the memory 124 of controller 120.
FIG. 4 illustrates a plot 70 showing example electrical loads drawn by the climate control system 10 per unit time during a peak period 71 of an example day according to some embodiments. The “peak period” 71 may refer to the period of the day when temperatures are generally warmest that may start in the late morning (or late “AM” period) through the late afternoon (during the early “PM” periods). Specifically, the peak period 71 may comprise the portion of the day when the temperatures rise above a threshold. The outdoor ambient temperature during the peak period 71 may resemble a portion of a sinusoidal curve that smoothly increases to a peak temperature occurring at a peak temperature time 75 (e.g., in the mid-afternoon in some cases) and then smoothly decreases from the peak temperature.
The plot 70 of FIG. 4 shows data sets 72, 74 of the electrical loads drawn by the climate control system 10 when operating to achieve the desired output cooling capacity for the interior space(s) of the building 12. Specifically, the data sets shown in the plot 70 of FIG. 4 include a first data set 72 showing the electrical load drawn by the climate control system 10 per unit time when solely utilizing the chillers 15 to satisfy the output cooling demand for the building 12, and a second data set 74 showing the electrical load drawn by the climate control system 10 per unit time when utilizing both the chillers 15 and the TES 60 to satisfy the output cooling demand for the building 12 based on the non-linear operating efficiency of the chillers 15 according to embodiments disclosed herein.
As may be appreciated from the data sets 72, 74 shown in FIG. 4 , the first data set 72 (utilizing the chillers 15 alone to satisfy the cooling demand of the building 12), the electrical load drawn by the climate control system 10 increases along with the outdoor ambient temperature during the peak period 71 and thus also resembles a sinusoidal curve having a peak electrical load 78 occurring at (or about) the peak temperature time 75, and periods of increasing and decreasing electrical loads before and after the peak temperature time 75, respectively. Conversely, when the climate control system 10 is operated to satisfy the cooling demand of the building 12 by use of select combinations of the chillers 15 at select output cooling capacities in concert with distribution of low-temperature fluid 64 from the TES 60 according to embodiments disclosed herein, the electrical load drawn by the climate control system 10 during the peak period 71 illustrated in FIG. 4 may be substantially maintained at or below a baseline electrical load 76 that is less than the peak electrical load 78. Thus, according to the second data set 74, the electrical load drawn by the climate control system 10 may be flattened at or about the baseline electrical load 76, and the characteristic increases and decreases in electrical load associated with the first data set 72 may be avoided (or at least substantially reduced).
Referring still to FIGS. 1 and 4 , during operation, the controller 120 may receive a weather forecast for the upcoming day (or the upcoming peak period 71), and the weather forecast may include a forecasted temperature profile for the day. The weather forecast may be received from any suitable source, including a weather service, news agency, etc. In some embodiments, the temperature profile of the weather forecast may comprise the expected temperatures for the upcoming day over some graduation (e.g., such as hour-to-hour, every half hour, every five minutes, etc.). The controller 120 may determine the peak temperature for the upcoming day using the weather forecast and also may determine a total available cooling capacity that may be delivered from the TES 60 during the peak period 71 (e.g., via low-temperature fluid 64 and heat exchangers 62 as previously described). In some embodiments, the controller 120 may determine the total available cooling capacity that may be delivered from the TES 60 by use of one or more sensors (e.g., temperature sensors, volume sensors, level sensors, etc.) that may indicate the available volume and temperature of the low-temperature fluid 64 that may be delivered from the TES 60.
Using these sources of information, the controller 120 may then determine an operational plan for the climate control system 10 during the upcoming peak period 71. In determining the operational plan for the climate control system 10, the controller 120 may first determine a combination of the chillers 15 at select operating levels along with supplemental cooling distribution from the TES 60 that will provide the desired cooling capacity to the interior space(s) of the building 12 for the peak temperature time 75 (and thus at the peak expected temperatures) at a lowered baseline electrical load 76 that is less than the expected peak electrical load 78 that would be associated with solely operating the chillers 15 (e.g., first data set 72 in FIG. 4 ) as previously described. In some embodiments, controller 120 may determine the baseline electrical load 76 by selecting the combination of chillers 15 and their respective output cooling capacities that will require the lowest electrical load (e.g., in KW) per unit of cooling capacity (e.g., in Tons) to provide the cooling demand of the building 12 in combination with the available cooling capacity from the TES 60 based at least in part on the unique non-linear variances of operational efficiency for the chillers 15 (e.g., chart 32 in FIG. 3 ) as previously described.
The newly determined baseline electrical load 76 may then be set, by controller 120, as the maximum electrical load for the climate control system 10 during the other portions of the peak period 71 (and indeed through the entire twenty-four-hour day in some cases). In particular, after determining the new baseline electrical load 76 based on the forecasted peak temperature at the peak temperature time 75 and available cooling capacity of the TES 60, the controller 120 may determine the additional combinations (and operating levels) of the chillers 15 and distributions of low-temperature fluid 64 from the TES 60 that will provide the desired cooling capacity for the interior space(s) of building 12 at the other forecasted temperatures during the peak period 71 (both before and after the peak temperature time 75) without exceeding the determined baseline electrical load 76.
When determining the operational plan of the climate control system 10, the controller 120 may determine a most efficient combination and operating levels of the chillers 15 based on the operating efficiencies and expected output cooling capacities provided by the chart(s) 32 (FIG. 3 ) as previously described. Because the data provided in the chart(s) 32 may be continuously updated as previously described the controller 120 may accurately determine the most efficient combinations (and operating levels) of chillers 15 for operating the climate control system 10 based on the outdoor ambient temperature throughout the life of the climate control system 10.
As the controller 120 is determining the combinations of chillers 15 and TES 60 distribution(s) to achieve the cooling demand at or below the baseline electrical load 76, the controller 120 may also determine whether the forecasted distributions of TES 60 will efficiently meter out and therefore completely discharge the available cooling capacity from the TES 60 throughout the entire peak period 71 without either fully dispensing the available cooling capacity from the TES 60 before the end of the peak period 71 or leaving cooling capacity (or excess cooling capacity above a threshold or safety reserve) after the end of the peak period 71. If an initial distribution plan determined by the controller 120 results in such an inefficient distribution from the TES 60, the controller 120 may reinitiate the entire process described above to determine a new baseline electrical load 76 that will allow for the efficient distribution of the cooling capacity of the TES 60 throughout the peak period 71.
During the peak period 71, the controller 120 may execute the planned operation of the climate control system 10 to as to ensure operation at the baseline electrical load 76. However, deviations of the actual temperature away from the forecasted temperature profile during the peak period 71 may necessitate additional operational adjustments by the controller 120. Specifically, the controller 120 may operate a different combination of chillers 15 at different operational levels and/or may distribute different rates of low-temperature fluid 64 from the TES 60 through select heat exchangers 62 to provide the desired cooling capacity at the deviated temperature and without exceeding the baseline electrical load 76 during operation. As previously described, the controller 120 may again determine the most efficient combination of chillers 15 (and their associated operating levels) by use of the charts 32 (FIG. 3 ) and the available cooling capacity in the TES 60, when adjusting the operation of the climate control system 10 to account for the deviated temperature(s).
When designing the climate control system 10 for the building 12, an operational plan for the climate control system 10 may be determined based on a worst-case forecast temperature (or temperature profile) for a twenty-four-hour period. The worst-case forecast temperature (or profile) may correspond with a hottest temperature observed for the geographic area in which the building 12 is positioned over some historical period (e.g., such as over the last twenty years in some cases). The parameters (e.g., type, number, size, etc.) of the chillers 15 and the parameters (e.g., type, size, capacity, etc.) of the TES 60 may be determined so that the cooling demand associated with the worst-case forecast temperature (or profile) may be satisfied by the climate control system 10 while maintaining the electrical load at or below a desired (or at maximum desirable) baseline electrical load (e.g., baseline electrical load 76). The parameters of both the chillers 15 and the TES 60 may be further determined by any additional system constraints, such as for instance the available space that may be occupied by the climate control system 10, any equipment requirements of the climate control system 10 (e.g., requirement to only use air-cooled chillers or water-cooled chillers, etc.), the availability or desirability of a particular TES 60 type, etc. The final designed climate control system 10 may be configured to provide the worst-case cooling demand (e.g., based on the worst-case forecast temperature) at the desired baseline electrical load 76.
The difference ΔP between the baseline electrical load 76 and the theoretical peak electrical load 78 that may be expended by a chiller-only climate control system may represent additional electrical load capacity that may be monetized or more efficiently utilized elsewhere as noted herein. In particular, in the case of some commercial buildings (such as data centers, for instance), the additional electrical load capacity (e.g., ΔP) may be sold to building tenants (e.g., to operate their electrical equipment) to thereby generate additional revenue for the building operator.
Referring now to FIG. 5 , an embodiment of climate control system 10 is shown that includes a particular example of the TES 60. Generally speaking, the TES 60 may be configured as a fluid tank 100 that may store a volume of the low-temperature fluid 64, and that may deliver the low-temperature fluid 64 to and from the heat exchangers 62 to supplement the cooling capacity of the chillers 15 as previously described. The low-temperature fluid 64 stored in the fluid tank 100 may be charged be one or more recharge chillers 102 during operations. The recharge chillers 102 may be generally configured the same as the chillers 15 (FIG. 2 ) and thus may utilize a refrigerant circuit to cool the low-temperature fluid 64 prior to outputting the low-temperature fluid 64 back to the cold storage tank 100 for storage and subsequent distribution as previously described.
The recharge chillers 102 and the chillers 15 may be energized via a common bus bar 106 (or other suitable electrical power distribution system). The controller 120 may control and adjust the operation of the recharge chillers 102 and chillers 15 via the bus bar 106 or directly (and not via the bus bar 106) during operations. The bus bar 106 may be energized by the local electrical grid 114.
In addition, the TES 60 (or the climate control system 10 more broadly) may include a solar power generation assembly 111. For instance, the solar power generation assembly 111 may include one or more photovoltaic cells (or solar panels) that are configured to convert sunlight 112 into electrical current. The electrical current generated by the solar power generation assembly 111 may be direct current (DC). As a result, the electrical current generated by the solar power generation assembly 111 may be converted to alternating current (AC) by an DC-to-AC inverter 108. The inverted DC electrical current may then be conducted from the DC-to-AC inverter 108 to the bus bar 106. The controller 120 may be communicatively coupled to the bus bar 106 so that the controller 120 may monitor and determine how much electrical current is conducted to the bus bar 106 via the solar power generation assembly 111.
During operation of the climate control system 10, the controller 120 may gain additional operational efficiency via utilization of the recharge chillers 102 and solar power generation assembly 111. In particular, reference is made to FIG. 6 which illustrates a plot 200 showing example electrical loads drawn by the embodiment of the climate control system 10 shown in FIG. 5 per unit time during over an example day according to some embodiments. The plot 200 of FIG. 6 may show both the peak period 71 illustrated in FIG. 4 , and a non-peak period 202 that together make up the twenty-four-hour day. The “non-peak period” 202 may refer to the period of the day when temperatures are generally coolest that may start in the late afternoon or early evening (or late PM period) through the late morning (during the late “AM” periods). As previously described, the peak period 71 may comprise the portion of the day when the temperatures rise above a threshold, and conversely, the non-peak period 202 may comprise the remaining portion of the day when the temperature are at or below the threshold. The outdoor ambient temperature during the non-peak period 71 may also resemble a portion of a sinusoidal curve that smoothly decreases to a minimum temperature (e.g., in the early AM hours in some cases) and then smoothly increases toward the peak period 71.
As with the plot 70 in FIG. 4 , the plot 200 of FIG. 6 shows data sets 72, 74, including the first data set 72 showing the electrical load drawn by the climate control system 10 per unit time when solely utilizing the chillers 15 to satisfy the output cooling demand for the building 12 without the TES 60, and a second data set 74 showing the electrical load drawn by the climate control system 10 per unit time when utilizing both the chillers 15 and the TES 60 to satisfy the output cooling demand for the building 12 based on the non-linear operating efficiency of the chillers 15 according to embodiments disclosed herein. In the plot 200, the data sets 72, 74 are extended to also show performance during both the peak period 71 and the non-peak period 202 and with reference to the embodiment of climate control system 10 shown in FIG. 5 .
Because the non-peak period 202 may represent a period of time when outdoor ambient temperatures are generally lower, the controller 120 may be able to satisfy the cooling demand of the interior space(s) in the building 12 using the chillers 15 without any distributions from the TES 60 and at an electrical load value that is below the baseline electrical load 76 that was established based on the upcoming peak period (or another peak period as previously described). This reduction in the electrical load drawn by the climate control system 10 may be indicative of the reduced electrical load draw illustrated in the non-peak period for the first data set 72 in FIG. 6 . As a result, the controller 120 may have additional electrical load capacity during the non-peak period 202 that is characterized as the difference between the baseline electrical load 76 for the peak period 71 and the reduced electrical load during the non-peak period 202. Because the building owner or operator may generally reserve electrical capacity up to the baseline electrical load 76 for operation of the climate control system 10, this unused electrical load during the non-peak period 202 cannot generally be utilized for other purposes, and thus may represent a “waste” from the perspective of the building operator. Accordingly, the controller 120 may utilize this additional electrical load capacity during the non-peak period 202 to recharge the TES 60 to allow for the subsequent distribution of the low-temperature fluid 64 during the subsequent peak period 71.
Specifically, in some embodiments, during the non-peak period 202, the controller 120 may operate the recharge chillers 102 so as to recharge the tank 100 with cold low-temperature fluid 64. During this process, the controller 120 may limit the operation of the recharge chillers 102 (e.g., via adjustments to the speeds of the compressors 26 of one or more of the recharge chillers 102) so that the overall electrical load drawn by the climate control system 10 (including the recharge chillers 102 and the chillers 15) may be at or below the baseline electrical load 76. Thus, the overall effect is to further flatten the electrical load drawn by the climate control system 10 generally at (or under) the baseline electrical load for both the peak period 71 and non-peak period 202.
Moreover, during the peak period 71, the embodiment of the climate control system 10 may be operated to achieve additional operational efficiencies compared to that already described herein. Specifically, during the peak period 71, the sun may be above the horizon line so that the solar power generation assembly 111 may be generating electrical current that is provided by the bus bar 106 as previously described. The electrical current generated by the solar power generation assembly 111 may represent additional electrical current that does not contribute to (and thus may be used to offset) the electrical power drawn from the electrical power grid 114. As a result, the controller 120 may utilize the electrical current generated by the solar power generation assembly 111 to supplement the operation of the climate control system 10 (including the chillers 15 and/or the TES 60).
For instance, in some embodiments, during the peak period 71, the controller 120 may operate one or more of the recharge chillers 102 at an electrical load that equals (or is less than) the total electrical current that is being generated by the solar power generation assembly 111 so as to further recharge the tank 100 and extend and enhance potential distributions of low temperature fluid 64 from the tank 100 during the peak period 71. As a result, the use of the electrical current generated by the solar power generation assembly 111 may be used to increase the effective capacity of the tank 100 without necessitating a volume increase thereof. Also, by limiting the operation of the recharge chillers 102 to an electrical load that is equal to or less than the total electrical current generated by the solar power generation assembly 111 may allow the recharge chillers 102 to operate without adding additional net electrical load to the bus bar 106.
In addition, in some embodiments, during the peak period 71, the controller 120 may operate the chillers 15 at a greater operational level so that a total electrical load of the climate control system 10 may be above the baseline electrical load 76 during the peak period 71, but only by an amount that is equal to (or less than) the electrical current that is being generated by the solar power generation assembly 111. The additional electrical load utilized by the chillers 15 via the electrical current generated by the solar power generation assembly 111 may provide additional cooling capacity that may reduce the distribution rate or volume from the TES 60 during the peak period (which again may allow for more efficient or optimal distributions therefrom).
Generally speaking, the embodiment of climate control system 10 shown in FIG. 5 may allow for a more aggressive baseline electrical load 76 during operations. Specifically, the additional cooling capacities provided by the recharge chillers 102 as well as the solar power generation assembly 111 may allow the climate control system 10 to achieve and maintain a relatively lower baseline electrical load 76 during, even worst-case peak periods 71. As a result, the embodiment of the climate control system 10 may allow for even additional electrical load capacity that may be monetized or otherwise used by the building owner or operator as previously described.
In addition, it should be appreciated that additional source of cooling capacity may be temporarily utilized with the climate control system 10 (e.g., either the embodiment shown in FIG. 1 or the embodiment shown in FIG. 5 ) to provide additional cooing capacity to deal with uncharacteristically high electrical loads (e.g., due to heat waves or other weather events) without operating the climate control system 10 above the baseline electrical load 76. For instance, in some embodiments, additional tanks of cool or cold fluid (e.g., liquid nitrogen, liquid CO₂, etc.) may be temporarily coupled to the TES 60 to supplement the cooling capacity provided via the TES 60 and therefore avoid further increases in the electrical load drawn by the chillers 15 to satisfy the cooling demand of the interior space(s) of building 12.
Referring now to FIG. 7 , a method 300 of operating a climate control system for a building (e.g., such as building 12) is shown according to some embodiments. The method 300 may be performed using the embodiments of climate control system 10 shown in FIGS. 1 and 5 ; however, it should be appreciated that embodiments of method 300 may be performed by use of climate control systems that may be different from the embodiments of climate control system 10 shown in FIGS. 1 and 5 in at least some respects.
Initially, method 300 includes receiving weather data for an upcoming day for a geographic area in which a building is located at block 302. The weather data may comprise a weather forecast, and at the least may include a predicted temperature profile (e.g., temperature vs time) for the upcoming day. In some embodiments, the weather data may also include sun-light forecasts that can be used to predict the effectiveness or efficiency of a solar power generation assembly (e.g., such as solar power generation assembly 111 shown in FIG. 5 ).
In addition, method 300 includes determining a total cooling capacity available from a thermal energy storage (TES) assembly of a climate control system for the building at block 304. The TES assembly may comprise any one or more of the TES assemblies previously described herein as the TES 60 in FIG. 1 . Thus, in some embodiments, the TES assembly in block 304 may comprise a source of low-temperature fluid, such as a fluid tank. The low-temperature may comprise low-temperature water or other low-temperature aqueous fluid that may be stored in the tank and distributed therefrom during operations.
Further, method 300 includes determining a baseline electrical load to operate the climate control system based at least on the weather data and the total cooling capacity available from the TES assembly at block 306. Still further, method 300 includes determining an output cooling capacity of a plurality of chillers of the climate control system and a distribution from the TES assembly that is configured to satisfy a cooling demand of the building at an electrical load of the climate control system that is at or below the baseline electrical load. For instance, as previously described above for embodiments of the climate control system 10 shown in FIGS. 1 and 5 , the controller 120 may determine a baseline electrical load 76 (FIGS. 4 and 6 ) of the climate control system 10 that may be a lowest electrical load of the climate control system 10 to supply the cooling demand to the interior space(s) of the building 12 at a peak temperature of the upcoming day using both the chillers 15 and distributions of the low-temperature fluid 64 from the TES 60. Once the baseline electrical load 76 is determined, the controller 120 may adjust operation of both the chillers 15 and distribution of low-temperature fluid from the TES 60 to satisfy the cooling demand for the building 12 while maintaining a total electrical load of the climate control system 10 at or below the baseline electrical load 76.
As explained above and reiterated below, the present disclosure includes, without limitation, the following example implementations.
Clause 1: A climate control system for conditioning an interior space, the climate control system comprising: an interior space heat exchange circuit that is configured to circulate a working fluid to cool an airflow that is directed to the interior space; a chiller that is configured to cool the working fluid; and a thermal energy storage (TES) assembly including: a source of low-temperature fluid; and a heat exchanger that is coupled to the interior space heat exchange circuit such that the heat exchanger is upstream of the chiller along the interior space heat exchange circuit, the heat exchanger configured to receive a flow of the low-temperature fluid from the source to cool the working fluid to thereby supplement an output cooling capacity of the chiller.
Clause 2: The climate control system of any of the clauses, wherein the chiller includes a refrigeration circuit including a compressor that is configured to operate at a plurality of different speeds to adjust the output cooling capacity of the chiller.
Clause 3: The climate control system of any of the clauses, wherein the source of low-temperature fluid comprises a tank that is configured to hold a volume of the low-temperature fluid, and wherein the TES assembly further comprises a recharge chiller that is configured to reduce a temperature of the low-temperature fluid and output the low-temperature fluid to the tank.
Clause 4: The climate control system of any of the clauses, wherein the TES assembly further includes one or more valves that are configured to control a flow of cold fluid to the heat exchanger.
Clause 5: The climate control system of any of the clauses, further comprising a controller that is configured to: adjust a flow of the cold fluid to the heat exchanger; and adjust an output cooling capacity of the chiller.
Clause 6: The climate control system of any of the clauses, further comprising: a bus bar that is electrically coupled to the chiller and the recharge chiller; and a solar power generation assembly that is electrically coupled to the bus bar.
Clause 7: A climate control system for conditioning an interior space, the climate control system comprising: an interior space heat exchange circuit that is configured to circulate a working fluid to cool an airflow that is directed to the interior space; a plurality of chillers that are configured to cool the working fluid; a thermal energy storage (TES) assembly that is thermally coupled to the interior space heat exchange circuit via a plurality of heat exchangers that are arranged along the interior space heat exchange circuit; and a controller communicatively coupled to the plurality of chillers and the TES assembly, wherein the controller is configured to adjust an output cooling capacity of the plurality of chillers and to adjust a distribution of cooling capacity from the TES assembly to maintain an electrical load of the climate control system at or below a baseline electrical load.
Clause 8: The climate control system of any of the clauses, wherein the TES assembly includes a source of low-temperature fluid that is in fluid communication with the plurality of heat exchangers, wherein the plurality of heat exchangers that are each positioned upstream of a corresponding one of the plurality of chillers along the interior space heat exchange circuit.
Clause 9: The climate control system of any of the clauses, wherein the controller is configured to adjust the distribution of cooling capacity from the TES assembly by adjusting a flow of low-temperature fluid from the source to one or more of the plurality of heat exchangers.
Clause 10: The climate control system of any of the clauses, wherein each chiller of the plurality of chillers includes a refrigeration circuit including a compressor, and wherein the controller is configured to adjust the output cooling capacity of the plurality of chillers by adjusting a speed of the compressor of one or more of the plurality of heat exchangers.
Clause 11: The climate control system of any of the clauses, wherein the source of low-temperature fluid comprises a tank that is configured to hold a volume of the low-temperature fluid, and wherein the TES further comprises one or more recharge chillers that are configured to reduce a temperature of the low-temperature fluid and output the low-temperature fluid to the tank.
Clause 12: The climate control system of any of the clauses, further comprising: a bus bar that is electrically coupled to the plurality of chillers and the one or more recharge chillers; and a solar power generation assembly that is electrically coupled to the bus bar, wherein the controller is configured to operate the one or more recharge chillers so that an electrical load of the one or more recharge chillers is equal to or less than an electrical current generated by the solar power generation assembly.
Clause 13: The climate control system of any of the clauses, wherein the controller is configured to: receive weather forecast for an upcoming day; and determine the baseline electrical load based at least in part on a maximum temperature in the weather forecast.
Clause 14: The climate control system of any of the clauses, wherein the controller is also configured to determine the baseline electrical load based at least in part on a cooling capacity stored in the TES assembly.
Clause 15: A method of operating a climate control system for a building, the method comprising: (a) receiving weather data for an upcoming day for a geographic area in which the building is located; (b) determining a total cooling capacity available from a thermal energy storage (TES) assembly of the climate control system; (c) determining a baseline electrical load to operate the climate control system based at least on the weather data and the total cooling capacity available from the TES assembly; and (d) determining an output cooling capacity of a plurality of chillers of the climate control system and a distribution of cooling capacity from the TES assembly that is configured to satisfy a cooling demand of the building at an electrical load of the climate control system that is at or below the baseline electrical load.
Clause 16: The method of any of the clauses, wherein the plurality of chillers are configured to cool a working fluid that is flowing along an interior space heat exchange circuit of the climate control system, wherein the TES assembly includes: a source of low-temperature fluid; and a plurality of heat exchangers that are coupled to the interior space heat exchange circuit such that each of the plurality of heat exchangers is upstream of a corresponding one of the plurality of chillers along the interior space heat exchange circuit, the plurality of heat exchangers configured to receive a flow of the low-temperature fluid from the source to cool the working fluid; and wherein the method further comprises: (e) distributing cooling capacity from the TES assembly according to the distribution by adjusting a flow of the low-temperature fluid to one or more of the plurality of heat exchangers.
Clause 17: The method of any of the clauses, wherein each chiller of the plurality of chillers includes a refrigeration circuit including a compressor; and wherein the method further comprises: (f) adjusting an output cooling capacity of one or more of the plurality of chillers by adjusting a speed of the compressor of each of the one or more of the plurality of chillers.
Clause 18: The method of any of the clauses, wherein the source of low-temperature fluid of the TES assembly comprises a tank; wherein the TES assembly further comprises one or more recharge chillers that are configured to reduce a temperature of the low-temperature fluid and output the low-temperature fluid to the tank; wherein the method further comprises: (g) determining an electrical current that is generated by a solar power generation assembly of the climate control system; and (h) operating the one or more recharge chillers so that an electrical load of the one or more recharge chillers is equal to or less than the electrical current generated by the solar power generation assembly.
Clause 19: The method of any of the clauses, wherein the source of low-temperature fluid of the TES assembly comprises a tank; wherein the TES assembly further comprises one or more recharge chillers that are configured to reduce a temperature of the low-temperature fluid and output the low-temperature fluid to the tank; wherein the method further comprises: (i) determining that an electrical load of the climate control system is below the baseline electrical load; and (j) operating the one or more recharge chillers so that a difference between the electrical load of the climate control system and the baseline electrical load is reduced in response to (i).
Clause 20: The method of any of the clauses, wherein the weather data includes a temperature profile for the upcoming day, wherein (c) comprises determining a baseline electrical load that is configured to provide for a complete discharge of the cooling capacity available from the TES assembly distributed over a peak period of the temperature profile for the upcoming day.
The embodiments disclosed herein include systems and methods for designing and operating a climate control system that are configured to substantially flatten the electrical load requirements for the climate control system over a twenty-four-hour period. In some embodiments, a climate control system according to embodiments disclosed herein may employ a thermal storage assembly that is configured to supplement the output capacity of the climate control system during peak periods so that a peak electrical load for the climate control system may be substantially reduced. Thus, by use of the embodiments disclosed herein, a commercial building owner or operator may reduce the total electrical load that must be reserved for operation of the building's climate control system, and this additional electrical load capacity may be further monetized or used for other purposes.
The preceding discussion is directed to various exemplary embodiments. However, one of ordinary skill in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.
The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.
In the discussion herein and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection of the two devices, or through an indirect connection that is established via other devices, components, nodes, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a given axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the given axis. For instance, an axial distance refers to a distance measured along or parallel to the axis, and a radial distance means a distance measured perpendicular to the axis. Further, when used herein (including in the claims), the words “about,” “generally,” “substantially,” “approximately,” and the like, when used in reference to a stated value mean within a range of plus or minus 10% of the stated value.
While exemplary embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.

Claims

What is claimed is:

1. A climate control system for conditioning an interior space, the climate control system comprising:

an interior space heat exchange circuit that is configured to circulate a working fluid to cool an airflow that is directed to the interior space;

a chiller that is configured to cool the working fluid; and

a thermal energy storage (TES) assembly including:

a source of low-temperature fluid; and

a heat exchanger that is coupled to the interior space heat exchange circuit such that the heat exchanger is upstream of the chiller along the interior space heat exchange circuit, the heat exchanger configured to receive a flow of the low-temperature fluid from the source to cool the working fluid to thereby supplement an output cooling capacity of the chiller.

2. The climate control system of claim 1, wherein the chiller includes a refrigeration circuit including a compressor that is configured to operate at a plurality of different speeds to adjust the output cooling capacity of the chiller.

3. The climate control system of claim 1, wherein the source of low-temperature fluid comprises a tank that is configured to hold a volume of the low-temperature fluid, and wherein the TES assembly further comprises a recharge chiller that is configured to reduce a temperature of the low-temperature fluid and output the low-temperature fluid to the tank.

4. The climate control system of claim 3, wherein the TES assembly further includes one or more valves that are configured to control a flow of cold fluid to the heat exchanger.

5. The climate control system of claim 4, further comprising a controller that is configured to:

adjust a flow of the cold fluid to the heat exchanger; and

adjust an output cooling capacity of the chiller.

6. The climate control system of claim 4, further comprising:

a bus bar that is electrically coupled to the chiller and the recharge chiller; and

a solar power generation assembly that is electrically coupled to the bus bar.

7. A climate control system for conditioning an interior space, the climate control system comprising:

a plurality of chillers that are configured to cool the working fluid;

a thermal energy storage (TES) assembly that is thermally coupled to the interior space heat exchange circuit via a plurality of heat exchangers that are arranged along the interior space heat exchange circuit; and

a controller communicatively coupled to the plurality of chillers and the TES assembly, wherein the controller is configured to adjust an output cooling capacity of the plurality of chillers and to adjust a distribution of cooling capacity from the TES assembly to maintain an electrical load of the climate control system at or below a baseline electrical load.

8. The climate control system of claim 7, wherein the TES assembly includes a source of low-temperature fluid that is in fluid communication with the plurality of heat exchangers, wherein the plurality of heat exchangers that are each positioned upstream of a corresponding one of the plurality of chillers along the interior space heat exchange circuit.

9. The climate control system of claim 8, wherein the controller is configured to adjust the distribution of cooling capacity from the TES assembly by adjusting a flow of low-temperature fluid from the source to one or more of the plurality of heat exchangers.

10. The climate control system of claim 8, wherein each chiller of the plurality of chillers includes a refrigeration circuit including a compressor, and wherein the controller is configured to adjust the output cooling capacity of the plurality of chillers by adjusting a speed of the compressor of one or more of the plurality of heat exchangers.

11. The climate control system of claim 8, wherein the source of low-temperature fluid comprises a tank that is configured to hold a volume of the low-temperature fluid, and wherein the TES further comprises one or more recharge chillers that are configured to reduce a temperature of the low-temperature fluid and output the low-temperature fluid to the tank.

12. The climate control system of claim 11, further comprising:

a bus bar that is electrically coupled to the plurality of chillers and the one or more recharge chillers; and

a solar power generation assembly that is electrically coupled to the bus bar,

wherein the controller is configured to operate the one or more recharge chillers so that an electrical load of the one or more recharge chillers is equal to or less than an electrical current generated by the solar power generation assembly.

13. The climate control system of claim 7, wherein the controller is configured to:

receive weather forecast for an upcoming day; and

determine the baseline electrical load based at least in part on a maximum temperature in the weather forecast.

14. The climate control system of claim 13, wherein the controller is also configured to determine the baseline electrical load based at least in part on a cooling capacity stored in the TES assembly.

15. A method of operating a climate control system for a building, the method comprising:

(a) receiving weather data for an upcoming day for a geographic area in which the building is located;

(b) determining a total cooling capacity available from a thermal energy storage (TES) assembly of the climate control system;

(c) determining a baseline electrical load to operate the climate control system based at least on the weather data and the total cooling capacity available from the TES assembly; and

(d) determining an output cooling capacity of a plurality of chillers of the climate control system and a distribution of cooling capacity from the TES assembly that is configured to satisfy a cooling demand of the building at an electrical load of the climate control system that is at or below the baseline electrical load.

16. The method of claim 15,

wherein the plurality of chillers are configured to cool a working fluid that is flowing along an interior space heat exchange circuit of the climate control system,

wherein the TES assembly includes:

a source of low-temperature fluid; and

a plurality of heat exchangers that are coupled to the interior space heat exchange circuit such that each of the plurality of heat exchangers is upstream of a corresponding one of the plurality of chillers along the interior space heat exchange circuit, the plurality of heat exchangers configured to receive a flow of the low-temperature fluid from the source to cool the working fluid; and

wherein the method further comprises:

(e) distributing cooling capacity from the TES assembly according to the distribution by adjusting a flow of the low-temperature fluid to one or more of the plurality of heat exchangers.

17. The method of claim 16,

wherein each chiller of the plurality of chillers includes a refrigeration circuit including a compressor; and

wherein the method further comprises:

(f) adjusting an output cooling capacity of one or more of the plurality of chillers by adjusting a speed of the compressor of each of the one or more of the plurality of chillers.

18. The method of claim 16,

wherein the source of low-temperature fluid of the TES assembly comprises a tank;

wherein the TES assembly further comprises one or more recharge chillers that are configured to reduce a temperature of the low-temperature fluid and output the low-temperature fluid to the tank;

wherein the method further comprises:

(g) determining an electrical current that is generated by a solar power generation assembly of the climate control system; and

(h) operating the one or more recharge chillers so that an electrical load of the one or more recharge chillers is equal to or less than the electrical current generated by the solar power generation assembly.

19. The method of claim 16,

wherein the method further comprises:

(i) determining that an electrical load of the climate control system is below the baseline electrical load; and

(j) operating the one or more recharge chillers so that a difference between the electrical load of the climate control system and the baseline electrical load is reduced in response to (i).

20. The method of claim 15, wherein the weather data includes a temperature profile for the upcoming day, wherein (c) comprises determining a baseline electrical load that is configured to provide for a complete discharge of the cooling capacity available from the TES assembly distributed over a peak period of the temperature profile for the upcoming day.