FIELD
[0001] This disclosure relates generally to heating and cooling systems that are selectively
operable in a cascaded operation or a parallel operation. More specifically, the disclosure
relates to a heating, ventilation, air conditioning, and refrigeration (HVACR) system
to condition a space and methods for operating heat transfer circuits in cascaded
operation or parallel operation.
BACKGROUND
[0002] A heating and cooling system can be used to heat and cool one or more process fluids
for a variety of applications. For example, the heating and cooling system can be
used to heat a heating load and/or cool a cooling load for industrial processes, such
as, heating and/or cooling gas or liquid flows to maintain reaction temperatures or
temperature setpoints, cooling industrial waste, providing heat to replace gas boilers,
providing refrigeration, or the like. The heating and cooling system can also be used
to condition a space, for example, an HVACR system can be used to provide heating
and/or provide cooling for the conditioned space. In some cases, the HVACR system
can be a hydronic system that includes a heat transfer circuit to provide a liquid
process fluid, for example, water, a brine solution, or a glycol solution, as a heat-transfer
medium to condition a space in a building or occupied space. The HVACR system often
includes a heat transfer circuit system that can include one or more compressors,
expanders, a condenser, an evaporator, fans, filters, dampers, circulation pumps,
and various other equipment, in which the compressor(s), the condenser, the expander,
and the evaporator are fluidly connected.
SUMMARY
[0003] This disclosure relates generally to heating and cooling systems that are selectively
operable in a cascaded operation or a parallel operation. More specifically, the disclosure
relates to a heating, ventilation, air conditioning, and refrigeration (HVACR) system
to condition a space and methods for operating heat transfer circuits in cascaded
operation or parallel operation.
[0004] The HVACR system can be a hydronic system in which thermal energy in a heat transfer
circuit is exchanged with process fluid(s), e.g., ethylene glycol, propylene glycol,
water, a brine solution, or the like, which is used to condition a space. For example,
when providing heating to the conditioned space, the heat generated from the compression
of a working fluid in the heat transfer circuit can be used to reject thermal energy
into the process fluid that is circulated in a heating water circuit of the hydronic
system to condition the space. Similarly, for providing cooling to the conditioned
space, the HVACR system can extract heat from a second process fluid that is circulated
in a chilled water circuit of the hydronic system to cool the process fluid to condition
the space.
[0005] In an embodiment, a heating and cooling system is provided. The heating and cooling
system includes a first heat transfer circuit, in which the first heat transfer circuit
includes a first compressor, a first heat exchanger, and a second heat exchanger;
a second heat transfer circuit, in which the second heat transfer circuit includes
a second compressor, a third heat exchanger, and a fourth heat exchanger; a coolant
loop including a coolant, the coolant loop configured to thermally communicate thermal
energy between the second heat exchanger of the first heat transfer circuit and the
third heat exchanger of the second heat transfer circuit; and a controller. The controller
is configured to selectively operate the heating and cooling system in: a heating
mode, in which the heating and cooling system is configured to operate the first heat
transfer circuit and the second heat transfer circuit in a cascaded operation to heat
a first process fluid via heat transfer with the first heat exchanger, in which the
coolant loop is configured to thermally communicate the thermal energy between the
third heat exchanger of the second heat transfer circuit and the second heat exchanger
of the first heat transfer circuit, and a cooling mode, in which the heating and cooling
system is configured to operate the first heat transfer circuit and the second heat
transfer circuit in parallel operation to both provide cooling to a second process
fluid via heat transfer with the fourth heat exchanger and the second heat exchanger.
[0006] In another embodiment, a heating, ventilation, air conditioning, and refrigeration
(HVACR) system is provided. The HVACR system includes a hydronic system including
a first process fluid and a second process fluid for conditioning one or more spaces;
a first heat transfer circuit, in which the first heat transfer circuit comprises
a first compressor, a first heat exchanger, and a first chiller, in which the first
heat exchanger is configured to selectively exchange heat with the first process fluid,
and the first process fluid further exchanges heat with a heating load in the one
or more spaces, or exchanges heat with cooling fluid; a second heat transfer circuit,
in which the second heat transfer circuit includes a second compressor, a cascade
heat exchanger, and a second chiller; in which the second chiller is configured to
exchange heat between the second process fluid, in which the second process fluid
further exchanges heat with a cooling load; a coolant loop including a coolant, the
coolant loop configured to thermally communicate thermal energy between the first
chiller of the first heat transfer circuit and the cascade heat exchanger of second
heat transfer circuit; and a controller. The controller is configured to selectively
operate the HVACR system in: a heating mode, in which the HVACR system is configured
to operate the first heat transfer circuit and the second heat transfer circuit in
a cascaded operation to heat the first process fluid via heat transfer with the first
heat exchanger, in which the coolant loop is configured to thermally communicate the
thermal energy between the cascade heat exchanger of the second heat transfer circuit
and the first chiller of the first heat transfer circuit, and a cooling mode, wherein
the HVACR system is configured to operate the first heat transfer circuit and the
second heat transfer circuit in a parallel operation to provide cooling to the second
process fluid via heat transfer with the first chiller and the second chiller, in
which the first heat exchanger is configured to exchange heat with the cooling fluid.
[0007] In yet another embodiment, a method for heating and/or cooling a system is provided.
The system includes a first heat transfer circuit, in which the first heat transfer
circuit includes a first compressor, a first heat exchanger, and a second heat exchanger;
a second heat transfer circuit, in which the second heat transfer circuit includes
a second compressor, a third heat exchanger, and a fourth heat exchanger; a coolant
loop including a coolant; and a controller. The method includes selectively operating
the system in either one of the following modes: operating the system in a heating
mode by operating the first heat transfer circuit and the second heat transfer circuit
in a cascaded operation to heat a first process fluid via heat transfer with the first
heat exchanger, in which the operating the system in the heating mode includes thermally
communicating, via the coolant loop, thermal energy from the third heat exchanger
of the second heat transfer circuit and the second heat exchanger of the first heat
transfer circuit; or operating the system in a cooling mode by operating the first
heat transfer circuit and the second heat transfer circuit in parallel operation to
provide cooling to a second process fluid, in which the operating the system in the
cooling mode includes providing the second process fluid to the fourth heat exchanger
and the second heat exchanger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] References are made to the accompanying drawings that form a part of this disclosure
and which illustrate the embodiments in which systems and methods described in this
specification can be practiced.
FIG. 1 illustrates a schematic diagram of a heating and/or cooling system, according
to an embodiment.
FIG. 2 illustrates a schematic diagram of a HVACR system, according to another embodiment.
FIG. 3 illustrates a schematic diagram of a HVACR system operating in a heating mode,
according to an embodiment.
FIG. 4 illustrates a schematic diagram of a HVACR system operating in a cooling mode,
according to an embodiment.
FIG. 5 illustrates a schematic diagram of a HVACR system, according to yet another
embodiment.
FIG. 6 is a flowchart of a control method of heating and/or cooling a system, according
to an embodiment.
[0009] Like reference numbers represent like parts throughout.
DETAILED DESCRIPTION
[0010] In the following detailed description, reference is made to the accompanying drawings,
which form a part of the description. In the drawings, similar symbols typically identify
similar components, unless context dictates otherwise. Furthermore, unless otherwise
noted, the description of each successive drawing may reference features from one
or more of the previous drawings to provide clearer context and a more substantive
explanation of the current example embodiment. Still, the example embodiments described
in the detailed description, drawings, and claims are not intended to be limiting.
Other embodiments may be utilized, and other changes may be made, without departing
from the spirit or scope of the subject matter presented herein. It will be readily
understood that the aspects of the present disclosure, as generally described herein
and illustrated in the drawings, may be arranged, substituted, combined, separated,
and designed in a wide variety of different configurations, all of which are explicitly
contemplated herein.
[0011] Particular embodiments of the present disclosure are described herein with reference
to the accompanying drawings; however, it is to be understood that the disclosed embodiments
are merely examples of the disclosure, which may be embodied in various forms. Well-known
functions or constructions are not described in detail to avoid obscuring the present
disclosure in unnecessary detail. Therefore, specific structural and functional details
disclosed herein are not to be interpreted as limiting, but merely as a basis for
the claims and as a representative basis for teaching one skilled in the art to variously
employ the present disclosure in virtually any appropriately detailed structure. In
this description, as well as in the drawings, like-referenced numbers represent elements
that may perform the same, similar, or equivalent functions.
[0012] Additionally, the present disclosure may be described herein in terms of functional
block components and various processing steps. It should be appreciated that such
functional blocks may be realized by any number of hardware and/or software components
configured to perform the specified functions.
[0013] The scope of the disclosure should be determined by the appended claims and their
legal equivalents, rather than by the examples given herein. For example, the steps
recited in any method claims may be executed in any order and are not limited to the
order presented in the claims. Moreover, no element is essential to the practice of
the disclosure unless specifically described herein as "critical" or "essential."
[0014] A heating and cooling system can be used to heat a heating load and/or cool a cooling
load for a variety of applications. In some embodiments, the heating and cooling system
can be used to heat a heating load and/or cool a cooling load for industrial processes,
such as, heating and/or cooling gas or liquid flows to maintain reaction temperatures
or temperature setpoints, cooling industrial waste, providing heat to replace gas
boilers, providing refrigeration, or the like. In some embodiments, the heating and
cooling system can be an HVACR system that can be used to provide comfort heating,
e.g., during the cold months or winter season, and provide comfort cooling, e.g.,
during the hot months or summer season. In some embodiments, the HVACR system can
include a hydronic system in which thermal energy in a heat transfer circuit is exchanged
with process fluid(s), e.g., ethylene glycol, propylene glycol, water, a brine solution,
or the like, which is used to condition a space. The hydronic system 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 the conditioned space. The conditioned
space can be a space within an office building, a commercial building, a factory,
a laboratory, a data center, a residential building, or the like. For example, when
providing heating to the conditioned space, the heat generated from the compression
of a working fluid in the heat transfer circuit can be used to reject heat to the
process fluid that is circulated in a heating water circuit to condition the space.
Similarly, for providing cooling to the conditioned space, the HVACR system can extract
heat from a second process fluid that is circulated in a chilled water circuit of
the hydronic system to cool the process fluid to condition the space.
[0015] In prior heating and cooling systems, the heating and cooling system can include
a low temperature circuit and a high temperature circuit, which can be operated in
a cascaded operation to achieve the heating temperatures, for example, to provide
comfort heating. In other prior heating and cooling systems, the heating and cooling
system can include compressors arranged in series (on the refrigerant circuit to provide
two stages of lift) to achieve the heating temperatures. However, once the heating
season is over, the high temperature circuit (or the compressor in series to provide
the additional lift) is idle, while the low temperature circuit (or single compressor)
can be used to provide the cooling temperatures, for example, to provide comfort cooling,
but at a lower capacity, e.g., only mass flow from a single compressor can be used
to provide cooling.
[0016] In order to overcome such deficiencies, the present disclosure relates to systems
and methods for improving the utilization and the operability of the heating and cooling
system. The systems and methods enable a heat transfer circuit to be selectively operable
in a heating mode to achieve heating temperatures or a cooling mode to provide cooling
temperatures such that the heat transfer circuits are configured to be operable during
both the heating and cooling seasons. As such, in some embodiments, for example, when
the heating and cooling system is the HVACR system, the heat transfer circuit can
be configured to provide cooling temperatures for a cooling load, for example, by
using a cooling fluid from a cooling tower to reject heat into the atmosphere, during
the hot months or summer season, and to provide heating temperatures for a heating
load, for example, by using heating air handlers to provide heat to condition a space
or building, during the cold months or winter season. In some embodiments, the HVACR
system can be configured to provide the heating temperatures by having a first heat
transfer circuit and a second heat transfer circuit arranged in a cascaded operation,
such that a fluid heated by the second heat transfer circuit, e.g., hot water, is
sent to the first heat transfer circuit to boost the temperatures in the first heat
transfer circuit. The HVACR system can also be configured to provide the cooling temperatures
by having the first heat transfer circuit and the second heat transfer circuit arranged
in parallel operation. That is, the HVACR system is configured to be reconfigured
from a hydronic series arrangement into a hydronic parallel arrangement, which can
provide additional cooling capacity, e.g., using mass flow from at least two compressors
for cooling the cooling load. Thus, when there is no heating demand in the summer,
the heat transfer circuit can be configured to run as a conventional chiller, whereas,
while there is significant heat load in the winter, the heat transfer circuit can
be configured to run as a high temperature chiller heater to provide the heating temperatures.
[0017] FIG. 1 shows a schematic diagram of a heating and cooling system 100 for heating
and/or cooling process fluid(s) using a compression cycle of a working fluid. The
process fluid(s) can be part of an industrial process, for example, process fluids
for reactions, industrial waste, refrigeration lines, heating lines, or the like,
or for a hydronic system for conditioning a space or building. The working fluid can
be any suitable working fluid, such as a refrigerant or blend thereof. In the embodiment
shown in FIG. 1, the heating and cooling system 100 is configured to provide cooling
in a chiller system, however it is understood that heating and cooling systems including
compressors according to embodiments can also be arranged as heat pumps, reversible
systems, or any other suitable system providing heating and/or cooling through a compression
cycle of a working fluid.
[0018] The heating and cooling system 100 includes a first heat transfer circuit 110, a
second heat transfer circuit 120, a coolant loop 130, and a controller 170. The first
heat transfer circuit 110 includes a working fluid circuit that includes a compressor
112, a first heat exchanger 114, for example, a condenser, an expansion device 116,
and a second heat exchanger 118, for example, an evaporator, and the second heat transfer
circuit 120 includes a working fluid circuit that includes a compressor 122, a third
heat exchanger 124, for example, a condenser, an expansion device 126, and a fourth
heat exchanger 128, for example, an evaporator. In an embodiment, the first heat transfer
circuit 110 and/or the second heat transfer circuit 120 can be modified to include
additional components. For example, the first heat transfer circuit 110 and/or the
second heat transfer circuit 120, in an embodiment, can include an economizer heat
exchanger, one or more flow control devices, a receiver tank, a dryer, a suction-liquid
heat exchanger, or the like. While the first heat transfer circuit 110 and the second
heat transfer circuit 120 can have different functions and/or components, the operation
of the working fluid circuit of the first heat transfer circuit 110 is discussed below,
in which the second heat transfer circuit 120 can have the same or different operation.
[0019] The compressor 112 is configured to compress a working fluid. Compressor 112 can
be any suitable compressor, such as a screw compressor, a scroll compressor, a centrifugal
compressor, or the like. Working fluid from compressor 112 can pass to condenser 114.
Condenser 114 is a heat exchanger allowing the working fluid to reject heat to a process
fluid, thereby heating the process fluid, e.g., for heating a heating load 140. The
rejection of heat to the heating load 140 can be to, for example, an ambient environment,
a heating process fluid, a heating load, or any other suitable sink for the heat being
rejected by the working fluid at condenser 114. The working fluid can pass from condenser
114 to expander 116. At expander 116 the working fluid is expanded. Expander 116 can
be any suitable expander, such as at least one expansion valve, expansion orifice,
orifice plate, expansion nozzle, a controllable expander, such as an electronic expansion
valve, combinations thereof, or the like. Working fluid can pass from expander 116
to evaporator 118 where the working fluid can extract heat from a source such as for
cooling a cooling load or coolant, thereby evaporating the working fluid prior to
the working fluid returning to compressor 112. The sources can be, for example, from
a process fluid or a conditioned space to be cooled, from an ambient environment,
or the like, so as to evaporate the working fluid. Non-limiting examples of evaporator
118 can include an evaporator of a chiller configured to cool a process fluid, coils
for cooling air to be distributed to a conditioned space, or the like. Working fluid
leaving the evaporator 118 can be returned to a suction of the compressor 112, and
the working fluid can continue to be circulated in first heat transfer circuit 110.
[0020] In some embodiments, the first heat exchanger 114, e.g., condenser, of the first
heat transfer circuit 110 and/or the third heat exchanger 124, e.g., condenser, of
the second heat transfer circuit 120 can be a dual-bundled heat exchanger, such as,
a dual-bundled shell and tube heat exchanger or dual-bundled plate heat exchanger.
It is appreciated that while the first heat exchanger 114 and the third heat exchanger
124 are discussed as being a single unit, such disclosure is not intended to be limiting.
Rather, the first heat exchanger 114 and/or the third heat exchanger 124 can have
different configurations, such as, the heat exchanger including several units, including,
but not limited to, a single-bundle condenser and external isolation heat exchanger
on one, the other or both of the units, in which one of the condenser or the external
isolation heat exchanger receives cooling fluid from the cooling source 160, while
the other unit receives the coolant from the coolant loop 130. As such, the first
heat exchanger 114 can be selectively configurable to reject heat to either a process
fluid for heating a heating load 140 or to reject heat to a cooling fluid from a cooling
device 160, for example, cooling water in a cooling fluid loop from a cooling tower
or other cooling source or air from a cooling fan, while the third heat exchanger
124 can be selectively configurable to reject heat to either a coolant from the coolant
loop 130 or to reject heat to the cooling fluid from the cooling device 160, for example,
cooling water from a cooling tower or other cooling source or air from a cooling fan,
as will be discussed further below.
[0021] The coolant loop 130 can include a coolant and one or more of valve(s), pump(s),
filters, stainers, or the like, for controlling fluid flow between the second heat
exchanger 118, e.g., evaporator, of the first heat transfer circuit 110 and the third
heat exchanger 124, e.g., condenser, of the second heat transfer circuit 120. The
coolant can be, but not limited to, ethylene glycol, propylene glycol, water, a brine
solution, or the like. The one or more valves can include a three-way feed valve,
e.g., two position valve, or a four-way feed valve, e.g., three position valve, to
allow the selectable connection of fluid to be cooled by the evaporator 118, e.g.,
connection to either the coolant in the coolant loop 130 or the second process fluid
for cooling the cooling load 150, as will be discussed further below.
[0022] The controller 170 can be a controller that is programmed, designed, or otherwise
configured to control one or more components of the heating and cooling system 100
and/or is a building automation system (BAS) controller for a computerized network
of electronic devices that can be configured to control one or more systems (e.g.,
mechanical, electrical, lighting, security, HVACR, or the like). The controller 170
can include one or more processors and one or more non-volatile storage memories having
instructions, which when executed by the one or more processors, carry out control
operations, as discussed herein. In some embodiments, the controller 170 can include
programmability to enable receiving and/or receiving a signal to heat or cool, e.g.,
from the BAS controller. For example, a building load can be determined based on seasonality,
e.g., winter or summer, such that when there is no heating demand, e.g., in the summer,
the first heat transfer circuit can be selectively operated in a cooling mode, whereas,
when there is heating demand, e.g., in the winter, the first heat transfer circuit
can be selectively operated in a heating mode, in which the controller 170 is configured
to selectively provide one or more of the coolant, the second process fluid from the
coolant load, or cooling fluid from the cooling device 160 to one or more of the heat
exchanger(s). As such, the heating and cooling system 100 can be optimized for use
in either heating or cooling throughout the year.
[0023] For example, in an embodiment, the controller 170 can receive a control request to
operate the heating and cooling system 100 in a heating mode, e.g., from the BAS controller
when heating is required, such as during winter season. As such, the controller 170
can be configured to operate the heating and cooling system 100 in a cascaded operation,
as follows. The controller 170 instructs the coolant loop 130 to supply coolant that
is in thermal communication with the second heat exchanger 118 and the third heat
exchanger 124, e.g., by sending instructions to open one or more of valve(s) and/or
to operate one or more pump(s) provided between the second heat exchanger 118 and
the third heat exchanger 124, and to heat a process fluid from the heating load 140,
e.g., by sending instructions to open one or more of valve(s) and/or to operate one
or more pump(s) provided between the first heat exchanger 114 and the heating load
140. In some embodiments, the controller 170 can instruct the coolant loop 130 to
close valves (and/or stop pump(s)) to isolate or stop supplying any process fluid
flow from the cooling load 150 to the second heat exchanger 118. In some embodiments,
the controller 170 can also instruct the cooling device 160 to stop the flow of any
cooling fluid to the third heat exchanger 124 and the first heat exchanger 114, e.g.,
by sending instructions to close one or more valves and/or stopping operation of one
or more pumps supplying the cooling fluid.
[0024] As such, in cascaded operation, the compressor 122 of the second heat transfer circuit
120 compresses the working fluid such that the heat generated during the compression
of the working fluid can be rejected in the third heat exchanger 124, e.g., condenser
of the second heat transfer circuit 120, to coolant flowing in the coolant loop 130.
The coolant in the coolant loop 130 is then used to thermally communicate thermal
energy from the third heat exchanger 124 to the second heat exchanger 118 of the first
heat transfer circuit 110 to provide thermal lift to heat the working fluid in the
first heat transfer circuit 110. Thus, the working fluid compressed by compressor
112 in the first heat transfer circuit 110 is at a higher (e.g., elevated) temperature
to provide heating or thermal energy, e.g., reject heat, via the first heat exchanger
114, to the process fluid of the heating load 140, which can be used for heating operations,
e.g., heating process flows and/or heating to condition a space or building.
[0025] In another embodiment, the controller 170 can receive a control request to operate
the heating and cooling system 100 in a cooling mode, e.g., from the BAS controller
when the heating demand of the building is below a threshold value, such as during
the summer season. As such, the controller 170 can be configured to operate the heating
and cooling system 100 in parallel operation, as follows. The controller 170 instructs
the coolant loop 130 to supply the second process fluid from the cooling load 150
to the second heat exchanger 118, e.g., by sending instructions to open one or more
of valve(s) and/or to operate one or more pump(s) provided between the second heat
exchanger 118 and the cooling load 150, and to provide cooling fluid from the cooling
device 160 to the third heat exchanger 124 and to the first heat exchanger 114 to
provide cooling of the working fluid, e.g., by sending instructions to open one or
more valve(s) and/or to operate one or more pumps between the cooling device 160 and
the first heat exchanger 114 and/or the third heat exchanger 124. In some embodiments,
the controller 170 can instruct the coolant loop 130 to close valves (and/or stop
pump(s)) to isolate or stop supplying any coolant flow from the coolant loop 130 between
the second heat exchanger 118 and the third heat exchanger 124. In some embodiments,
the controller 170 can also instruct the heating load 140 to stop the flow of any
process fluid to the first heat exchanger 114, e.g., by sending instructions to close
one or more valves and/or stopping operation of one or more pumps supplying the process
fluid from the heating load 140.
[0026] As such, in parallel operation, the compressor 112 of the first heat transfer circuit
110 and the compressor 122 of the second heat transfer circuit 120 compress the working
fluid such that the heat generated during the compression of the working fluid can
be rejected in the first heat exchanger 114 and the third heat exchanger 124, respectively,
by the cooling fluid from the cooling device 160. After expansion of the working fluid
by the expanders 116, 126, the second heat exchanger 118 and the fourth heat exchanger
128 are both configured to extract heat from the process fluid from the cooling load
150, thereby evaporating the working fluid prior to the working fluid returning to
the respective compressors 112, 122.
[0027] It is appreciated that the first heat transfer circuit 110 and the second heat transfer
circuit 120 can have the same or matched capacity, e.g., same cooling and/or heating
capacity, or can have mis-matched capacities which may further increase efficiency
and/or operating stability. For example, in an embodiment, the first heat transfer
circuit 110 can have a smaller capacity than the large capacity second heat transfer
circuit 120, e.g., 500 ton to 2000 ton unit and 1000 to 2000 ton unit. As such, the
heat and cooling system 100 can be designed or otherwise configured to be properly
sized for the heating load, e.g., heating of the coolant in the coolant loop 130 to
provide the lift for the first heat transfer circuit 110, while providing auxiliary
cooling for the cooling load during different seasons. In some embodiments, in which
the first heat transfer circuit 110 has a smaller capacity, it is understood that
one or more first heat transfer circuit(s) 110 can be used to heat the heating load
140, such that multiple first heat transfer circuit(s) 110 may provide better low
heating load efficiency and operational stability. Furthermore, it is understood that
the first heat exchanger 114 and/or the third heat exchanger 124 can have smaller
capacities to either match the capacity of the smaller unit first heat transfer circuit(s)
110 or to provide more efficient heating, which may also reduce system cost. That
is, in an embodiment, the third heat exchanger 124 can have a capacity that is matched
to the heating load.
[0028] Thus, the heating and cooling system 100 is configured to improve the utilization
and operability of the heating and cooling system 100, which was not obtainable by
the prior heating and cooling systems, by being able to utilize both the first heat
transfer circuit 110 and the second heat transfer circuit 120 for both a heating mode
to heat a process fluid for a heating load and a cooling mode to cool a process fluid
for a cooling load in parallel operation. As such, the heating and cooling system
100 can be used to provide high lift to heat a process fluid for a heating load and
provide additional cooling capacity, e.g., capacity to cool by the compressor(s),
during periods of high cooling demand that was not previously attainable by prior
heating and cooling systems, in which the prior heating and cooling systems had one
or more stages or circuits that are idle during different times, e.g., different seasons.
[0029] FIG. 2 shows a schematic diagram of a HVACR system 200 for heating and/or cooling
process fluid(s) using a compression cycle of a working fluid, which can have the
same or similar features as the heating and cooling system 100, as discussed above.
The HVACR system 200 can include a hydronic system that includes a first process fluid
loop 202 and a second process fluid loop 205 for conditioning a space or building.
The working fluid can be any suitable working fluid, such as a refrigerant or blend
thereof. In the embodiment shown in FIG. 2, the HVACR system 200 is configured to
provide cooling in a chiller system, however it is understood that heating and cooling
systems including compressors according to embodiments can also be arranged as heat
pumps, reversible systems, or any other suitable system providing heating and/or cooling
through a compression cycle of a working fluid.
[0030] The HVACR system 200 includes a first heat transfer circuit 210, a second heat transfer
circuit 220, a coolant loop 230, and a controller, which can be the controller 170
in FIG. 1. The first heat transfer circuit 210 includes a working fluid circuit that
includes a compressor (e.g., compressor 112 in FIG. 1), a first heat exchanger 214,
for example, a condenser, an expander (e.g., expander 116 in FIG. 1), and a first
chiller 218, for example, an evaporator, and the second heat transfer circuit 220
includes a working fluid circuit that includes a compressor (e.g., compressor 122
in FIG. 1), a cascade heat exchanger 224, for example, a condenser, an expander (e.g.,
expander 126 in FIG. 1), and a second chiller 228, for example, an evaporator.
[0031] In the first heat transfer circuit 210, the compressor is configured to compress
a working fluid. Compressor can be any suitable compressor, such as a screw compressor,
a scroll compressor, a centrifugal compressor, or the like. Working fluid from the
compressor can pass to the first heat exchanger 214. First heat exchanger 214 is a
heat exchanger that is configured to selectively exchange heat with the first process
fluid to allow the working fluid to reject heat to the process fluid, thereby heating
the first process fluid in the first process fluid loop 202, such that the first process
fluid can exchange heat for heating a heating load 240. The rejection of heat to the
heating load 240 can be to, for example, an ambient environment, a heating load, or
any other suitable sink for the heat being rejected by the working fluid at first
heat exchanger 214, e.g., for conditioning one or more spaces or buildings. The working
fluid can pass from the first heat exchanger 214 to the expander, which is configured
to expand the working fluid. Working fluid can pass from the expander to the first
chiller 218 where the working fluid can extract heat from a source, such as, for cooling
a cooling load or coolant, thereby evaporating the working fluid prior to the working
fluid returning to the compressor. The sources can be, for example, from a process
fluid or a conditioned space to be cooled, from an ambient environment, or the like,
so as to evaporate the working fluid. Working fluid leaving the first chiller 218
can be returned to a suction of the compressor, and the working fluid can continue
to be circulated in first heat transfer circuit 210.
[0032] In the second heat transfer circuit 220, the compressor is configured to compress
a working fluid. Working fluid from the compressor can pass to the cascade heat exchanger
224. Cascade heat exchanger 224 is a heat exchanger that is configured to selectively
exchange heat with coolant in coolant loop 230 to allow the working fluid to reject
heat to the coolant, thereby heating the coolant in the coolant loop 230, e.g., to
provide lift for refrigerant in the first heat transfer circuit 210, or to exchange
heat with cooling fluid from a cooling device 260, such as, a cooling tower, to allow
the working fluid to reject heat to the cooling fluid. The working fluid can pass
from the cascade heat exchanger 224 to the expander, which is configured to expand
the working fluid. Working fluid can pass from the expander to the second chiller
228 where the working fluid can extract heat from the second process fluid of the
second process fluid loop 205 for cooling the cooling load 250, thereby evaporating
the working fluid prior to the working fluid returning to the compressor. Working
fluid leaving the second chiller 228 can be returned to a suction of the compressor,
and the working fluid can continue to be circulated in second heat transfer circuit
220.
[0033] In some embodiments, the first heat exchanger 214 of the first heat transfer circuit
210 and/or the cascade heat exchanger 224 of the second heat transfer circuit 220
can be a dual-bundled heat exchanger, such as, a dual-bundled shell and tube heat
exchanger or dual-bundled plate heat exchanger. As such, the first heat exchanger
214 can be selectively configurable to reject heat to either a process fluid for heating
a heating load 240 or to reject heat to a cooling fluid from a cooling device 260,
for example, cooling water in a cooling fluid loop from a cooling tower or other cooling
source or air from a cooling fan, while the cascade heat exchanger 224 can be selectively
configurable to reject heat to either a coolant from the coolant loop 230 or to reject
heat to the cooling fluid from the cooling device 260.
[0034] The coolant loop 230 can include a coolant and one or more of valve(s), pump(s),
filters, stainers, or the like, for controlling fluid flow between the first chiller
218 of the first heat transfer circuit 210 and the cascade heat exchanger 224 of the
second heat transfer circuit 220. The coolant can be, but not limited to, ethylene
glycol, propylene glycol, water, a brine solution, or the like. The one or more valves
can include a three-way feed valve, e.g., two position valve, or a four-way feed valve,
e.g., three position valve, to allow the selectable connection of fluid to be cooled
by the first chiller 218, e.g., connection to either the coolant in the coolant loop
230 or the second process fluid for cooling the cooling load 250, as will be discussed
further below.
[0035] The controller can be a controller that is programmed, designed, or otherwise configured
to control one or more components of the HVACR system 200 and/or is a building automation
system (BAS) controller for a computerized network of electronic devices that can
be configured to control one or more systems (e.g., mechanical, electrical, lighting,
security, HVACR, or the like). The controller can include one or more processors and
one or more non-volatile storage memories having instructions, which when executed
by the one or more processors, carry out control operations, as discussed herein.
In some embodiments, the controller can include programmability to enable receiving
and/or receiving a signal to heat or cool, e.g., from the BAS controller. For example,
a building load can be determined based on seasonality, e.g., winter or summer, such
that when there is no heating demand, e.g., in the summer, the first heat transfer
circuit can be selectively operated in a cooling mode, whereas, when there is heating
demand, e.g., in the winter, the first heat transfer circuit can be selectively operated
in a heating mode, in which the controller is configured to selectively provide one
or more of the coolant, the second process fluid from the coolant load, or cooling
fluid from the cooling device 260 to one or more of the heat exchangers.
[0036] As such, the HVACR system 200 can be optimized for use for either heating or cooling,
as illustrated in FIGS. 3 and 4. As illustrated in FIG. 3, in an embodiment, the controller
can receive a control request to operate the HVACR system 200 in a heating mode, e.g.,
from the BAS controller when heating is required, such as during winter season. As
such, the controller can be configured to operate the HVACR system 200 in a cascaded
operation, as follows, in which the dash-dot lines present fluid lines not in operation.
The controller instructs the coolant loop 230 to supply coolant that is in thermal
communication with the first chiller 218 and the cascade heat exchanger 224, e.g.,
by sending instructions to open one or more of valve(s) 232, 234 and/or to operate
one or more pump(s) 236 provided between the first chiller 218 and the cascade heat
exchanger 224, and to heat a process fluid from the heating load 240, e.g., by sending
instructions to open one or more of valve(s) 203 and/or to operate one or more pump(s)
204 provided between the first heat exchanger 214 and the heating load 240. In some
embodiments, the controller can instruct the coolant loop 230 to close valves (and/or
stop pump(s)) to isolate or stop supplying any process fluid flow from the cooling
load 250 to the first chiller 218. In some embodiments, the controller can also instruct
the cooling device 260 to stop the flow of any cooling fluid to the cascade heat exchanger
224 and the first heat exchanger 214, e.g., by sending instructions to close one or
more valves and/or stopping operation of one or more pumps supplying the cooling fluid.
[0037] As such, in cascaded operation, the compressor of the second heat transfer circuit
220 compresses the working fluid such that the heat generated during the compression
of the working fluid can be rejected in the cascade heat exchanger 224 to coolant
flowing in the coolant loop 230, for example, to raise the temperature of the coolant
from 85°F to 95°F, e.g., Q = mCpΔT, in which the working fluid is subsequently cooled
by the second chiller 228, e.g., extracts heat from the second process fluid of the
second process fluid loop 205, e.g., lowers the temperature of the second process
fluid from 52°F to 42°F. The coolant in the coolant loop 230 is then used to thermally
communicate thermal energy from the cascade heat exchanger 224 to the first chiller
218 of the first heat transfer circuit 210 to provide thermal lift to heat the working
fluid in the first heat transfer circuit 210, e.g., since the coolant from the coolant
loop 230 has an increased amount of heat, the working fluid in the first heat transfer
circuit 210 has a higher lift, such that when the working fluid in the first heat
transfer circuit 210 is compressed, the compressed working fluid has a higher temperature,
e.g., an increased amount of heat which can raise the temperature of the first process
fluid in the first process fluid loop 202 from 140°F to 160°F to heat the heating
load 240, e.g., heating water supply. Thus, the working fluid compressed by compressor
in the first heat transfer circuit 210 is at a higher (e.g., elevated) temperature
to provide heating or thermal energy, via the first heat exchanger 214, to the process
fluid of the first process fluid loop 202 for heating the heating load 240, which
can be used for heating operations, e.g., heating to condition a space or building.
[0038] As illustrated in FIG. 4, in another embodiment, the controller can receive a control
request to operate the HVACR system 200 in a cooling mode, e.g., from the BAS controller
when the heating demand of the building is below a threshold value, such as during
the summer season. As such, the controller can be configured to operate the HVACR
system 200 in parallel operation, as follows, in which the dash-dot lines present
fluid lines not in operation. The controller instructs the coolant loop 230 to supply
the second process fluid from the cooling load 250 to the first chiller 218, e.g.,
by sending instructions to open one or more of valve(s) 232, 234 and/or to operate
one or more pump(s) provided between the first chiller 218 and the cooling load 250,
and to provide cooling fluid from the cooling device 260 to the cascade exchanger
224 and to the first heat exchanger 214 to provide cooling of the working fluid, e.g.,
by sending instructions to open one or more valve(s) and/or to operate one or more
pumps between the cooling device 260 and the first heat exchanger 214 and/or the cascade
heat exchanger 224. In some embodiments, the controller can instruct the coolant loop
230 to close valves 232, 234 (and/or stop pump(s) 236) to isolate or stop supplying
any coolant flow from the coolant loop 230 between the first chiller 218 and the cascade
heat exchanger 224. In some embodiments, the controller can also instruct the heating
load 240 to stop the flow of any process fluid in the first fluid process loop 202
to the first heat exchanger 214, e.g., by sending instructions to close one or more
valves 203 and/or stopping operation of one or more pumps 204 supplying the process
fluid for heating the heating load 240.
[0039] As such, in parallel operation, the compressor of the first heat transfer circuit
210 and the compressor of the second heat transfer circuit 220 compress the working
fluid such that the heat generated during the compression of the working fluid can
be rejected in the first heat exchanger 214 and the cascade heat exchanger 224, respectively,
by the cooling fluid from the cooling device 260, for example, rejecting heat to the
cooling fluid which increases the temperature of the cooling fluid from 85°F to 95°F.
After expansion of the working fluid by the expanders, the first chiller 218 and the
second chiller 228 are both configured to extract heat from the process fluid for
providing cooling to the cooling load 250, e.g., extracts heat from the second process
fluid of the second process fluid loop 205, e.g., lowers the temperature of the second
process fluid from 52°F to 42°F.
[0040] Thus, the HVACR system 200 is configured to improve the utilization and operability
of the HVACR system 200, which was not previously obtainable by the prior HVACR systems,
by being able to utilize both the first heat transfer circuit 210 and the second heat
transfer circuit 220 for both a heating mode to heat a process fluid for a heating
load (in a cascade hydronic series arrangement) and a cooling mode to cool a process
fluid for a cooling load in parallel operation (in a hydronic parallel arrangement)
that provides additional cooling capacity. As such, the HVACR system 200 can be used
to provide high lift to heat a process fluid for a heating load and provide additional
cooling capacity, e.g., capacity to cool by the compressor(s), during periods of high
cooling demand that was not previously attainable by prior HVACR systems, in which
the prior HVACR systems had one or more stages or circuits that are idle during different
times, e.g., different seasons.
[0041] FIG. 5 shows a schematic diagram of a HVACR system 500 for heating and/or cooling
process fluid(s) using a compression cycle of a working fluid, which can have the
same or similar features as the heating and cooling system 100 or the HVACR system
200, as discussed above. The HVACR system 500 can include a hydronic system that includes
a first process fluid loop 502 and a second process fluid loop 504 for conditioning
a space or building. The working fluid can be any suitable working fluid, such as
a refrigerant or blend thereof. In the embodiment shown in FIG. 5, the HVACR system
500 is configured to provide cooling in a chiller system and heating using a heat
pump system, however, it is understood that heating and cooling systems including
compressors according to embodiments can also be arranged as heat pumps, reversible
systems, or any other suitable system providing heating and/or cooling through a compression
cycle of a working fluid.
[0042] The HVACR system 500 includes a first heat transfer circuit 510, a second heat transfer
circuit 520, a coolant loop 530, and a controller, which can be the controller 170
in FIG. 1. The first heat transfer circuit 510 includes a working fluid circuit that
includes a compressor (e.g., compressor 112 in FIG. 1), a first heat exchanger 514,
for example, a condenser, an expander (e.g., expander 116 in FIG. 1), and a first
chiller 518, for example, an evaporator, and the second heat transfer circuit 520
includes a working fluid circuit that includes a compressor (e.g., compressor 122
in FIG. 1), a cascade heat exchanger 524, an auxiliary or isolation heat exchanger
525, an expander (e.g., expander 126 in FIG. 1), and a second chiller 528, for example,
an evaporator.
[0043] In the first heat transfer circuit 510, the compressor is configured to compress
a working fluid. Compressor can be any suitable compressor, such as a screw compressor,
a scroll compressor, a centrifugal compressor, or the like. Working fluid from the
compressor can pass to the first heat exchanger 514. First heat exchanger 514 is a
heat exchanger that is configured to selectively exchange heat with the first process
fluid (or cooling fluid (not shown) to allow the working fluid to reject heat to the
process fluid, thereby heating the first process fluid in the first process fluid
loop 502, such that the first process fluid can exchange heat for heating a heating
load 540. The rejection of heat to the heating load 540 can be to, for example, an
ambient environment, a heating load, or any other suitable sink for the heat being
rejected by the working fluid at first heat exchanger 514, e.g., for conditioning
one or more spaces or buildings. The working fluid can pass from the first heat exchanger
514 to the expander, which is configured to expand the working fluid. Working fluid
can pass from the expander to the first chiller 518 where the working fluid can extract
heat from a source, such as, for cooling a cooling load or coolant, thereby evaporating
the working fluid prior to the working fluid returning to the compressor. The sources
can be, for example, from a process fluid or a conditioned space to be cooled, from
an ambient environment, or the like, so as to evaporate the working fluid. Working
fluid leaving the first chiller 518 can be returned to a suction of the compressor,
and the working fluid can continue to be circulated in first heat transfer circuit
510.
[0044] In the second heat transfer circuit 520, the compressor is configured to compress
a working fluid. Working fluid from the compressor can pass to either the cascade
heat exchanger 524 and/or the auxiliary or isolation heat exchanger 525. Cascade heat
exchanger 524 is a heat exchanger that is configured to selectively exchange heat
with coolant in coolant loop 530 to allow the working fluid to reject heat to the
coolant, thereby heating the coolant in the coolant loop 530, e.g., to provide lift
for refrigerant in the first heat transfer circuit 510. The auxiliary or isolation
heat exchanger 525 is a heat exchanger configured to exchange heat with cooling fluid
from a cooling device 560, such as, a cooling tower, to allow the working fluid to
reject heat to the cooling fluid. The working fluid can pass from the cascade heat
exchanger 524 and/or the auxiliary or isolation heat exchanger 525 to the expander,
which is configured to expand the working fluid. Working fluid can pass from the expander
to the second chiller 528 where the working fluid can extract heat from the second
process fluid of the second process fluid loop 505 for cooling the cooling load 550,
thereby evaporating the working fluid prior to the working fluid returning to the
compressor. Working fluid leaving the second chiller 528 can be returned to a suction
of the compressor, and the working fluid can continue to be circulated in second heat
transfer circuit 520.
[0045] In some embodiments, the first heat exchanger 514 of the first heat transfer circuit
510 and/or the cascade heat exchanger 524 of the second heat transfer circuit 520
can include the auxiliary or isolation heat exchanger 525. As such, the first heat
exchanger 514 can be selectively configurable to reject heat to a process fluid for
heating a heating load 540, while the auxiliary or isolation heat exchanger can be
configurable to reject heat to a cooling fluid, e.g., from a cooling device 560, for
example, cooling water in a cooling fluid loop from a cooling tower or other cooling
source or air from a cooling fan (not shown). Similarly, the cascade heat exchanger
524 can be selectively configurable to reject heat to a coolant from the coolant loop
530, while the auxiliary or isolation heat exchanger 525 is configured to reject heat
to the cooling fluid from the cooling device 560. While the supply of cooling fluid
to the auxiliary or isolation heat exchanger 525 is discussed above, it is understood
that such disclosure is not intended to be limiting. For example, it is understood
that the cascade het exchanger 524 (or the first cheat exchanger 514) can instead
receive the cooling fluid from the cooling device 560, while the auxiliary or isolation
heat exchanger receives the other fluids.
[0046] The coolant loop 530 can include a coolant and one or more of valve(s), pump(s),
filters, stainers, or the like, for controlling fluid flow between the first chiller
518 of the first heat transfer circuit 510 and the cascade heat exchanger 524 of the
second heat transfer circuit 520. The coolant can be, but not limited to, ethylene
glycol, propylene glycol, water, a brine solution, or the like. The one or more valves
can include a three-way feed valve, e.g., two position valve, or a four-way feed valve,
e.g., three position valve, to allow the selectable connection of fluid to be cooled
by the first chiller 518, e.g., connection to either the coolant in the coolant loop
530 or the second process fluid for cooling the cooling load 550, as will be discussed
further below.
[0047] The controller can be a controller that is programmed, designed, or otherwise configured
to control one or more components of the HVACR system 500 and/or is a building automation
system (BAS) controller for a computerized network of electronic devices that can
be configured to control one or more systems (e.g., mechanical, electrical, lighting,
security, HVACR, or the like). The controller can include one or more processors and
one or more non-volatile storage memories having instructions, which when executed
by the one or more processors, carry out control operations, as discussed herein.
In some embodiments, the controller can include programmability to enable receiving
and/or receiving a signal to heat or cool, e.g., from the BAS controller. For example,
a building load can be determined based on seasonality, e.g., winter or summer, such
that when there is no heating demand, e.g., in the summer, the first heat transfer
circuit can be selectively operated in a cooling mode, whereas, when there is heating
demand, e.g., in the winter, the first heat transfer circuit can be selectively operated
in a heating mode, in which the controller is configured to selectively provide one
or more of the coolant, the second process fluid from the coolant load, or cooling
fluid from the cooling device 560 to one or more of the heat exchangers.
[0048] As such, the HVACR system 500 can be optimized for use for either heating or cooling.
In an embodiment, the controller can receive a control request to operate the HVACR
system 500 in a heating mode, e.g., from the BAS controller when heating is required,
such as during winter season. As such, the controller can be configured to operate
the HVACR system 500 in a cascaded operation, as follows. The controller instructs
the coolant loop 530 to supply coolant that is in thermal communication with the first
chiller 518 and the cascade heat exchanger 524, e.g., by sending instructions to open
one or more of valve(s) and/or to operate one or more pump(s) 536 provided between
the first chiller 518 and the cascade heat exchanger 524, and to heat a process fluid
from the heating load 540, e.g., by sending instructions to open one or more of valve(s)
and/or to operate one or more pump(s) provided between the first heat exchanger 514
and the heating load 540. In some embodiments, the controller can instruct the coolant
loop 530 and/or the second process fluid loop 505 to close valves (and/or stop pump(s))
to isolate or stop supplying any process fluid flow from the cooling load 550 to the
first chiller 518. In some embodiments, the controller can also instruct the cooling
device 560 to stop the flow of any cooling fluid to the auxiliary or isolation heat
exchanger 524 and the first heat exchanger 514, e.g., by sending instructions to close
one or more valves and/or stopping operation of one or more pumps supplying the cooling
fluid.
[0049] As such, in cascaded operation, the compressor of the second heat transfer circuit
520 compresses the working fluid such that the heat generated during the compression
of the working fluid can be rejected in the cascade heat exchanger 524 to coolant
flowing in the coolant loop 530. The coolant in the coolant loop 530 is then used
to thermally communicate thermal energy from the cascade heat exchanger 524 to the
first chiller 518 of the first heat transfer circuit 510 to provide thermal lift to
heat the working fluid in the first heat transfer circuit 510. Thus, the working fluid
compressed by compressor in the first heat transfer circuit 510 is at a higher (e.g.,
elevated) temperature to provide heating or thermal energy, via the first heat exchanger
514, to the process fluid of the first process fluid loop 502 for heating the heating
load 540, which can be used for heating operations, e.g., heating to condition a space
or building.
[0050] In another embodiment, the controller can receive a control request to operate the
HVACR system 500 in a cooling mode, e.g., from the BAS controller when the heating
demand of the building is below a threshold value, such as during the summer season.
As such, the controller can be configured to operate the HVACR system 500 in parallel
operation, as follows. The controller instructs the second process fluid loop 505
to supply the second process fluid from the cooling load 550 to the first chiller
518, e.g., by sending instructions to open one or more of valve(s) and/or to operate
one or more pump(s) provided between the first chiller 518 and the cooling load 550,
and to provide cooling fluid from the cooling device 560 to the auxiliary or isolation
heat exchanger 525 and to the first heat exchanger 514 to provide cooling of the working
fluid, e.g., by sending instructions to open one or more valve(s) and/or to operate
one or more pumps between the cooling device 560 and the first heat exchanger 514
and/or the auxiliary or isolation heat exchanger 525. In some embodiments, the controller
can instruct the coolant loop 530 to close valves (and/or stop pump(s) 536) to isolate
or stop supplying any coolant flow from the coolant loop 530 between the first chiller
518 and the cascade heat exchanger 524. In some embodiments, the controller can also
instruct the heating load 540 to stop the flow of any process fluid in the first fluid
process loop 502 to the first heat exchanger 514, e.g., by sending instructions to
close one or more valves and/or stopping operation of one or more pumps supplying
the process fluid for heating the heating load 540.
[0051] As such, in parallel operation, the compressor of the first heat transfer circuit
510 and the compressor of the second heat transfer circuit 520 compress the working
fluid such that the heat generated during the compression of the working fluid can
be rejected in the first heat exchanger 514 and the auxiliary or isolation exchanger
525, respectively, by the cooling fluid from the cooling device 560, for example,
rejecting heat to the cooling fluid which increases the temperature of the cooling
fluid from 85°F to 95°F. After expansion of the working fluid by the expanders, the
first chiller 518 and the second chiller 528 are both configured to extract heat from
the process fluid for providing cooling to the cooling load 550, e.g., extracts heat
from the second process fluid of the second process fluid loop 505, e.g., lowers the
temperature of the second process fluid from 52°F to 42°F.
[0052] Thus, the HVACR system 500 is configured to improve the utilization and operability
of the HVACR system 500, which was not previously obtainable by the prior HVACR systems,
by being able to utilize both the first heat transfer circuit 510 and the second heat
transfer circuit 520 for both a heating mode to heat a process fluid for a heating
load (in a cascade hydronic series arrangement) and a cooling mode to cool a process
fluid for a cooling load in parallel operation (in a hydronic parallel arrangement)
that provides additional cooling capacity. As such, the HVACR system 500 can be used
to provide high lift to heat a process fluid for a heating load and provide additional
cooling capacity, e.g., capacity to cool by the compressor(s), during periods of high
cooling demand that was not previously attainable by prior HVACR systems, in which
the prior HVACR systems had one or more stages or circuits that are idle during different
times, e.g., different seasons.
[0053] FIG. 6 is a flowchart for a method 600 for heating and/or cooling a system, for example,
the heating and cooling system 100 of FIG. 1 or the HVACR system 200 of FIG. 2 or
the HVACR system 500 of FIG. 5. The system includes a first heat transfer circuit
(e.g., 110, 210, 510), in which the first heat transfer circuit includes a first compressor
(e.g., 112), a first heat exchanger (e.g., 114, 214, 514), and a second heat exchanger
(e.g., 118, 218, 518); a second heat transfer circuit (e.g., 120, 220, 520), in which
the second heat transfer circuit includes a second compressor (e.g., 122), a third
heat exchanger (e.g., 124, 224, 524), and a fourth heat exchanger (e.g., 128, 228,
528); a coolant loop (e.g., 130, 230, 530) including a coolant; and a controller (e.g.,
170), according to an embodiment.
[0054] The method 600 can include one or more operations, actions, or functions depicted
by one or more blocks 610, 620, 630, and 640. Although illustrated as discrete blocks,
various blocks may be divided into additional blocks, combined into fewer blocks,
or eliminated, depending on the desired implementation. In an embodiment, the method
600 can be performed by the controller 170 of FIG. 1 or the BAS controller, or any
other suitable control systems or controllers. The method 600 may optionally begin
at block 610 for selectively operating the system in either one of a cascaded operation
or a parallel operation.
[0055] At block 610, "Receive a signal for heating a heating load or supplemental cooling
a cooling load", the controller is programmed, designed, or otherwise configured to
control one or more components of the heating and cooling system (or HVACR system)
and/or is a building automation system (BAS) controller for a computerized network
of electronic devices that can be configured to control one or more systems (e.g.,
mechanical, electrical, lighting, security, HVACR, or the like). The controller can
include one or more processors and one or more non-volatile storage memories having
instructions, which when executed by the one or more processors, carry out control
operations, as discussed herein. In some embodiments, the controller can include programmability
to enable receiving and/or receiving a signal to heat or cool, e.g., from the BAS
controller. For example, a building load can be determined based on seasonality, e.g.,
winter or summer, such that when there is no heating demand, e.g., in the summer,
the first heat transfer circuit can be selectively operated in a cooling mode, whereas,
when there is heating demand, e.g., in the winter, the first heat transfer circuit
can be selectively operated in a heating mode, in which the controller is configured
to selectively provide one or more of the coolant, the second process fluid from the
coolant load, or cooling fluid from the cooling device to one or more of the heat
exchangers. As such, the heating and cooling system (or HVACR system) can be optimized
for use in either heating or cooling. The method 600 can proceed to 620.
[0056] At 620, "Selectively operate the system to heat the heating load and/or cool the
cooling load," the controller is configured to receive a control request to selectively
operate the heating and cooling system in one of a "heating mode" and a "cooling mode,"
in which the first heat transfer circuit is operable in either a cascaded operation
or a parallel operation to enable utilization of the first heat transfer circuit for
all seasons. The method 600 can then proceed to either 630 or 640.
[0057] At 630, "Operate the system in a heating mode," in an embodiment, when the system
is operated in a heating mode, e.g., when heating is required and demand is high for
heating, such as during winter season, the controller can be configured to receive
the "heating mode" signal, e.g., from the BAS controller, and operate the heating
and cooling system in a cascaded operation, as follows. The controller instructs the
coolant loop to supply coolant that is in thermal communication with the second heat
exchanger and the third heat exchanger, e.g., by sending instructions to open one
or more of valve(s) and/or to operate one or more pump(s) provided between the second
heat exchanger and the third heat exchanger, and to heat a process fluid from the
heating load, e.g., by sending instructions to open one or more of valve(s) and/or
to operate one or more pump(s) provided between the first heat exchanger and the heating
load. That is, the controller is configured to selectively control the flow of the
coolant through the coolant, such as to provide either the coolant to the second heat
exchanger of the first heat transfer circuit (or the second process fluid to the second
heat exchanger in the cooling mode, as discussed below). In some embodiments, the
controller can instruct the coolant loop to close valves (and/or stop pump(s)) to
isolate or stop supplying any process fluid flow from the cooling load to the second
heat exchanger. In some embodiments, the controller can also instruct the cooling
device to stop the flow of any cooling fluid to the third heat exchanger and the first
heat exchanger, e.g., by sending instructions to close one or more valves and/or stopping
operation of one or more pumps supplying the cooling fluid. The method 600 can proceed
to 630.
[0058] As such, in cascaded operation, the compressor of the second heat transfer circuit
compresses the working fluid such that the heat generated during the compression of
the working fluid can be rejected in the third heat exchanger, e.g., condenser of
the second heat transfer circuit, to coolant flowing in the coolant loop. The coolant
in the coolant loop is then used to thermally communicate thermal energy from the
third heat exchanger to the second heat exchanger of the first heat transfer circuit
to provide thermal lift to heat the working fluid in the first heat transfer circuit.
Thus, the working fluid compressed by compressor in the first heat transfer circuit
is at a higher (e.g., elevated) temperature to provide heating or thermal energy,
e.g., reject heat, via the first heat exchanger, to the process fluid of the heating
load, which can be used for heating operations, e.g., heating process flows and/or
heating to condition a space or building.
[0059] At 640, "Operate the system in a cooling mode," in an embodiment when the system
is operated in a cooling mode, e.g., from the BAS controller when the heating demand
of the building is below a threshold value, such as during the summer season, the
controller can be configured to receive the "cooling mode" signal and operate the
heating and cooling system in a parallel operation, as follows. The controller instructs
the coolant loop to selectively supply the second process fluid from the cooling load
to the second heat exchanger, e.g., by sending instructions to open one or more of
valve(s) and/or to operate one or more pump(s) provided between the second heat exchanger
and the cooling load, and to provide cooling fluid from the cooling device to the
third heat exchanger and to the first heat exchanger to provide cooling of the working
fluid, e.g., by sending instructions to open one or more valve(s) and/or to operate
one or more pumps between the cooling device and the first heat exchanger and/or the
third heat exchanger, e.g., such that the first heat exchanger and the third heat
exchanger are condensers for their respective heat transfer circuits. In some embodiments,
the controller can instruct the coolant loop to close valves (and/or stop pump(s))
to isolate or stop supplying any coolant flow from the coolant loop between the second
heat exchanger and the third heat exchanger. In some embodiments, the controller can
also instruct the heating load to stop the flow of any process fluid to the first
heat exchanger, e.g., by sending instructions to close one or more valves and/or stopping
operation of one or more pumps supplying the process fluid from the heating load.
[0060] As such, in parallel operation, the compressor of the first heat transfer circuit
and the compressor of the second heat transfer circuit compress the working fluid
such that the heat generated during the compression of the working fluid can be rejected
in the first heat exchanger and the third heat exchanger, respectively, to the cooling
fluid from the cooling device. After expansion of the working fluid by the expander(s),
the second heat exchanger and the fourth heat exchanger are both configured to extract
heat from the process fluid from the cooling load, thereby evaporating the working
fluid prior to the working fluid returning to the respective compressors.
[0061] Thus, the heating and cooling system is configured to improve the utilization and
operability of the heating and cooling system, which was not obtainable by the prior
heating and cooling systems, by being able to utilize both the first heat transfer
circuit and the second heat transfer circuit for both a heating mode to heat a process
fluid for a heating load in cascaded operation and a cooling mode to cool a process
fluid for a cooling load in parallel operation. As such, the heating and cooling system
can be used to provide high lift to heat a process fluid for a heating load and provide
additional cooling capacity, e.g., capacity to cool by the compressor(s), during periods
of high cooling demand that was not previously attainable by prior heating and cooling
systems, in which the prior heating and cooling systems had one or more stages or
circuits that are idle during various times of the year, e.g., different seasons.
[0062] Aspects: It is appreciated that any one of aspects 1-9, any one of aspects 10-16, and any
one of aspects 17-19 can be combined with each other.
[0063] Aspect 1. A heating and cooling system comprising: a first heat transfer circuit,
wherein the first heat transfer circuit comprises a first compressor, a first heat
exchanger, and a second heat exchanger; a second heat transfer circuit, wherein the
second heat transfer circuit comprises a second compressor, a third heat exchanger,
and a fourth heat exchanger; a coolant loop including a coolant, the coolant loop
configured to thermally communicate thermal energy between the second heat exchanger
of the first heat transfer circuit and the third heat exchanger of the second heat
transfer circuit; and a controller, wherein the controller is configured to selectively
operate the heating and cooling system in: a heating mode, wherein the heating and
cooling system is configured to operate the first heat transfer circuit and the second
heat transfer circuit in a cascaded operation to heat a first process fluid via heat
transfer with the first heat exchanger, wherein the coolant loop is configured to
thermally communicate the thermal energy between the third heat exchanger of the second
heat transfer circuit and the second heat exchanger of the first heat transfer circuit,
and a cooling mode, wherein the heating and cooling system is configured to operate
the first heat transfer circuit and the second heat transfer circuit in parallel operation
to both provide cooling to a second process fluid via heat transfer with the fourth
heat exchanger and the second heat exchanger.
[0064] Aspect 2. The heating and cooling system of Aspect 1, wherein the third heat exchanger
of the second heat transfer circuit is configured to selectively receive cooling fluid
in the cooling mode or the coolant from the coolant loop in the heating mode.
[0065] Aspect 3. The heating and cooling system of any one of Aspects 1-2, wherein the first
heat exchanger of the first heat transfer circuit is configured to selectively receive
cooling fluid in the cooling mode or the first process fluid in the heating mode.
[0066] Aspect 4. The heating and cooling system of any one of Aspects 1-3, wherein the first
heat exchanger of the first heat transfer circuit and/or the third heat exchanger
of the second heat transfer circuit is a dual-bundled heat exchanger.
[0067] Aspect 5. The heating and cooling system of any of Aspects 1-3, wherein the first
heat exchanger of the first heat transfer circuit and/or the third heat exchanger
of the second heat transfer circuit includes an auxiliary heat exchanger.
[0068] Aspect 6. The heating and cooling system of any one of Aspects 1-5, wherein the coolant
loop includes one or more valves for controlling a flow of the coolant through the
coolant loop, and the controller is configured to operate the one or more valves to
selectively provide either the coolant to the second heat exchanger in the heating
mode or the second process fluid to the second heat exchanger in the cooling mode.
[0069] Aspect 7. The heating and cooling system of any one of Aspects 1-6, wherein the heating
and cooling system is a hydronic system, and the first process fluid is heating water
and the second process fluid is chilled water.
[0070] Aspect 8. The heating and cooling system of any one of Aspects 1-7, further comprising
a cooling fluid loop including one or more valves, wherein the controller is configured
to operate the one or more valves to supply cooling fluid to the first heat exchanger
of the first heat transfer circuit and the third heat exchanger of the second heat
transfer circuit in the cooling mode.
[0071] Aspect 9. The heating and cooling system of any one of Aspects 1-8, wherein the coolant
is at least one of: ethylene glycol, propylene glycol, water, and a brine solution.
[0072] Aspect 10. A heating, ventilation, air conditioning, and refrigeration (HVACR) system
comprising: a hydronic system comprising a first process fluid and a second process
fluid for conditioning one or more spaces; a first heat transfer circuit, wherein
the first heat transfer circuit comprises a first compressor, a first heat exchanger,
and a first chiller, wherein the first heat exchanger is configured to selectively
exchange heat with the first process fluid, wherein the first process fluid further
exchanges heat with a heating load in the one or more spaces, or exchanges heat with
cooling fluid; a second heat transfer circuit, wherein the second heat transfer circuit
comprises a second compressor, a cascade heat exchanger, and a second chiller; wherein
the second chiller is configured to exchange heat between the second process fluid,
wherein the second process fluid further exchanges heat with a cooling load; a coolant
loop including a coolant, the coolant loop configured to thermally communicate thermal
energy between the first chiller of the first heat transfer circuit and the cascade
heat exchanger of second heat transfer circuit; and a controller, wherein the controller
is configured to selectively operate the HVACR system in: a heating mode, wherein
the HVACR system is configured to operate the first heat transfer circuit and the
second heat transfer circuit in a cascaded operation to heat the first process fluid
via heat transfer with the first heat exchanger, wherein the coolant loop is configured
to thermally communicate the thermal energy between the cascade heat exchanger of
the second heat transfer circuit and the first chiller of the first heat transfer
circuit, and a cooling mode, wherein the HVACR system is configured to operate the
first heat transfer circuit and the second heat transfer circuit in a parallel operation
to provide cooling to the second process fluid via heat transfer with the first chiller
and the second chiller, wherein the first heat exchanger is configured to exchange
heat with the cooling fluid.
[0073] Aspect 11. The HVACR system of Aspect 10, wherein the cascade heat exchanger of the
second heat transfer circuit is configured to selectively receive the cooling fluid
or the coolant from the coolant loop.
[0074] Aspect 12. The HVACR system of any one of Aspects 10-11, wherein the first heat exchanger
of the first heat transfer circuit and/or the cascade heat exchanger of the second
heat transfer circuit is a dual-bundled heat exchanger.
[0075] Aspect 13. The HVACR system of any one of Aspects 10-11, wherein the first heat exchanger
of the first heat transfer circuit and/or the cascade heat exchanger of the second
heat transfer circuit includes an auxiliary heat exchanger.
[0076] Aspect 14. The HVACR system of any one of Aspects 10-13, wherein the coolant is at
least one of: ethylene glycol, propylene glycol, water, and a brine solution.
[0077] Aspect 15. The HVACR system of any one of Aspects 10-14, wherein the cooling fluid
is provided via a cooling fluid loop including one or more valves, wherein the controller
is configured to operate the one or more valves to supply the cooling fluid to the
first heat exchanger of the first heat transfer circuit and the cascade heat exchanger
of the second heat transfer circuit in the cooling mode.
[0078] Aspect 16. The HVACR system of any one of Aspects 10-15, wherein the coolant loop
includes one or more valves for controlling a flow of the coolant through the coolant
loop, and the controller is configured to operate the one or more valves to selectively
provide either the coolant to the first chiller in the heating mode or the second
process fluid to the first chiller in the cooling mode.
[0079] Aspect 17. A method for heating and/or cooling a system, the system comprising a
first heat transfer circuit, wherein the first heat transfer circuit comprises a first
compressor, a first heat exchanger, and a second heat exchanger; a second heat transfer
circuit, wherein the second heat transfer circuit comprises a second compressor, a
third heat exchanger, and a fourth heat exchanger; a coolant loop including a coolant;
and a controller, the method comprising selectively operating the system in either
one of the following modes: operating the system in a heating mode by operating the
first heat transfer circuit and the second heat transfer circuit in a cascaded operation
to heat a first process fluid via heat transfer with the first heat exchanger, wherein
the operating the system in the heating mode includes thermally communicating, via
the coolant loop, thermal energy from the third heat exchanger of the second heat
transfer circuit and the second heat exchanger of the first heat transfer circuit;
or operating the system in a cooling mode by operating the first heat transfer circuit
and the second heat transfer circuit in parallel operation to provide cooling to a
second process fluid, wherein the operating the system in the cooling mode includes
providing the second process fluid to the fourth heat exchanger and the second heat
exchanger.
[0080] Aspect 18. The method of Aspect 17, further comprising selectively controlling flow
of the coolant through the coolant loop to provide either the coolant to the second
heat exchanger of the first heat transfer circuit in the heating mode or the second
process fluid to the second heat exchanger in the cooling mode.
[0081] Aspect 19. The method of any one of Aspects 17-18, further comprising circulating
cooling fluid from a cooling fluid loop to selectively supply the cooling fluid to
the first heat exchanger of the first heat transfer circuit and the third heat exchanger
of the second heat transfer circuit in the cooling mode.
[0082] 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.
[0083] With regard to the preceding description, it is to be understood that changes may
be made in detail, especially in matters of the construction materials employed and
the shape, size, and arrangement of parts without departing from the scope of the
present disclosure. This specification and the embodiments described are exemplary
only, with the true scope and spirit of the disclosure being indicated by the claims
that follow.
1. A heating and cooling system (100) comprising:
a first heat transfer circuit (110, 210, 510), wherein the first heat transfer circuit
comprises a first compressor (112), a first heat exchanger (114, 214, 514), and a
second heat exchanger (118, 218, 518);
a second heat transfer circuit (120, 220, 520), wherein the second heat transfer circuit
comprises a second compressor (122), a third heat exchanger (124, 224, 524), and a
fourth heat exchanger (128, 228, 528);
a coolant loop (130, 230, 530) including a coolant, the coolant loop configured to
thermally communicate thermal energy between the second heat exchanger of the first
heat transfer circuit and the third heat exchanger of the second heat transfer circuit;
and
a controller (170), wherein the controller is configured to selectively operate the
heating and cooling system in:
a heating mode, wherein the heating and cooling system is configured to operate the
first heat transfer circuit and the second heat transfer circuit in a cascaded operation
to heat a first process fluid via heat transfer with the first heat exchanger, wherein
the coolant loop is configured to thermally communicate the thermal energy between
the third heat exchanger of the second heat transfer circuit and the second heat exchanger
of the first heat transfer circuit, and
a cooling mode, wherein the heating and cooling system is configured to operate the
first heat transfer circuit and the second heat transfer circuit in parallel operation
to both provide cooling to a second process fluid via heat transfer with the fourth
heat exchanger and the second heat exchanger.
2. The heating and cooling system of claim 1, wherein the third heat exchanger of the
second heat transfer circuit is configured to selectively receive cooling fluid in
the cooling mode or the coolant from the coolant loop in the heating mode.
3. The heating and cooling system of any one of claims 1-2, wherein the first heat exchanger
of the first heat transfer circuit is configured to selectively receive cooling fluid
in the cooling mode or the first process fluid in the heating mode, or
wherein the first heat exchanger of the first heat transfer circuit and/or the third
heat exchanger of the second heat transfer circuit is a dual-bundled heat exchanger,
or
wherein the first heat exchanger of the first heat transfer circuit and/or the third
heat exchanger of the second heat transfer circuit includes an auxiliary heat exchanger.
4. The heating and cooling system of any one of claims 1-3, wherein the coolant loop
includes one or more valves for controlling a flow of the coolant through the coolant
loop, and the controller is configured to operate the one or more valves to selectively
provide either the coolant to the second heat exchanger in the heating mode or the
second process fluid to the second heat exchanger in the cooling mode.
5. The heating and cooling system of any one of claims 1-4, wherein the heating and cooling
system is a hydronic system, and the first process fluid is heating water and the
second process fluid is chilled water.
6. The heating and cooling system of any one of claims 1-5, further comprising a cooling
fluid loop including one or more valves, wherein the controller is configured to operate
the one or more valves to supply cooling fluid to the first heat exchanger of the
first heat transfer circuit and the third heat exchanger of the second heat transfer
circuit in the cooling mode.
7. The heating and cooling system of any one of claims 1-6, wherein the coolant is at
least one of: ethylene glycol, propylene glycol, water, and a brine solution.
8. A heating, ventilation, air conditioning, and refrigeration (HVACR) system (200, 500)
comprising:
a hydronic system comprising a first process fluid and a second process fluid for
conditioning one or more spaces;
a first heat transfer circuit (110, 210, 510), wherein the first heat transfer circuit
comprises a first compressor (112), a first heat exchanger (114, 214, 514), and a
first chiller (218, 518),
wherein the first heat exchanger is configured to selectively exchange heat with the
first process fluid, wherein the first process fluid further exchanges heat with a
heating load (240) in the one or more spaces, or exchanges heat with cooling fluid;
a second heat transfer circuit (120, 220, 520), wherein the second heat transfer circuit
comprises a second compressor (122), a cascade heat exchanger (224, 524), and a second
chiller (228, 528);
wherein the second chiller is configured to exchange heat between the second process
fluid, wherein the second process fluid further exchanges heat with a cooling load
(250);
a coolant loop (130, 230, 530) including a coolant, the coolant loop configured to
thermally communicate thermal energy between the first chiller of the first heat transfer
circuit and the cascade heat exchanger of second heat transfer circuit; and
a controller (170), wherein the controller is configured to selectively operate the
HVACR system in:
a heating mode, wherein the HVACR system is configured to operate the first heat transfer
circuit and the second heat transfer circuit in a cascaded operation to heat the first
process fluid via heat transfer with the first heat exchanger, wherein the coolant
loop is configured to thermally communicate the thermal energy between the cascade
heat exchanger of the second heat transfer circuit and the first chiller of the first
heat transfer circuit, and
a cooling mode, wherein the HVACR system is configured to operate the first heat transfer
circuit and the second heat transfer circuit in a parallel operation to provide cooling
to the second process fluid via heat transfer with the first chiller and the second
chiller, wherein the first heat exchanger is configured to exchange heat with the
cooling fluid.
9. The HVACR system of claim 8, wherein the cascade heat exchanger of the second heat
transfer circuit is configured to selectively receive the cooling fluid or the coolant
from the coolant loop.
10. The HVACR system of any one of claims 8-9, wherein the first heat exchanger of the
first heat transfer circuit and/or the cascade heat exchanger of the second heat transfer
circuit is a dual-bundled heat exchanger, or wherein the first heat exchanger of the
first heat transfer circuit and/or the cascade heat exchanger of the second heat transfer
circuit includes an auxiliary heat exchanger.
11. The HVACR system of any one of claims 8-10, wherein the coolant is at least one of:
ethylene glycol, propylene glycol, water, and a brine solution.
12. The HVACR system of any one of claims 8-11, wherein the cooling fluid is provided
via a cooling fluid loop including one or more valves, wherein the controller is configured
to operate the one or more valves to supply the cooling fluid to the first heat exchanger
of the first heat transfer circuit and the cascade heat exchanger of the second heat
transfer circuit in the cooling mode.
13. The HVACR system of any one of claims 9-12, wherein the coolant loop includes one
or more valves for controlling a flow of the coolant through the coolant loop, and
the controller is configured to operate the one or more valves to selectively provide
either the coolant to the first chiller in the heating mode or the second process
fluid to the first chiller in the cooling mode.
14. A method for heating and/or cooling a system, the system comprising a first heat transfer
circuit, wherein the first heat transfer circuit comprises a first compressor, a first
heat exchanger, and a second heat exchanger; a second heat transfer circuit, wherein
the second heat transfer circuit comprises a second compressor, a third heat exchanger,
and a fourth heat exchanger; a coolant loop including a coolant; and a controller,
the method comprising selectively operating the system in either one of the following
modes:
operating the system in a heating mode by operating the first heat transfer circuit
and the second heat transfer circuit in a cascaded operation to heat a first process
fluid via heat transfer with the first heat exchanger, wherein the operating the system
in the heating mode includes thermally communicating, via the coolant loop, thermal
energy from the third heat exchanger of the second heat transfer circuit and the second
heat exchanger of the first heat transfer circuit; or
operating the system in a cooling mode by operating the first heat transfer circuit
and the second heat transfer circuit in parallel operation to provide cooling to a
second process fluid, wherein the operating the system in the cooling mode includes
providing the second process fluid to the fourth heat exchanger and the second heat
exchanger.
15. The method of claim 14, further comprising selectively controlling flow of the coolant
through the coolant loop to provide either the coolant to the second heat exchanger
of the first heat transfer circuit in the heating mode or the second process fluid
to the second heat exchanger in the cooling mode.