WO2013096902A1

WO2013096902A1 - Centralized multi-function heat exchange system

Info

Publication number: WO2013096902A1
Application number: PCT/US2012/071478
Authority: WO
Inventors: Dennis Michael NASUTA; Kurt Reinhard RADERMACHER
Original assignee: Optimized Thermal Systems, Llc
Priority date: 2011-12-22
Filing date: 2012-12-21
Publication date: 2013-06-27
Also published as: US20140223939A1

Abstract

A centralized heat exchange system for controlling a plurality of heat exchangers in heat pump cycle includes a plurality of heat exchanging units; a compressor; a network of refrigerant piping connected to each of the plurality of heat exchanging units and the compressor; and a controller configured to receive signals from sensors to monitor temperature or the like of spaces/compartments to be controlled. The controller controls the compressor and a reversing valve and expansion valves installed in the network of refrigerant piping to establish, in the network of refrigerant piping, one or more of a heat-pump loop that constitutes a vapor-compression cycle through an arrangement of a compressor, a condenser, an expansion valve, and an evaporator in accordance with a preset or user settable priority scheme that assigns at least one of the controlled spaces/compartments higher priority in control than the others.

Description

CENTRALIZED MULTI-FUNCTION HEAT EXCHANGE SYSTEM

This application claims the benefit of Provisional Application No. 61/579,531, filled December 22, 2011, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to a heat-pump system and apparatus. More specifically, the present invention relates to a centralized integrated system and apparatus for a multi-function heat pump with one or more of appliances, such as domestic or commercial hot water, refrigeration, and clothes dryer.

Description of the Related Art

A heat pump is an apparatus that uses a comparatively small amount of energy to move heat from one location to another. There are numerous homes around the world that contain a heat pump to distribute heat around the house. Currently, there are various heat pumps that can accomplish this task. However, there are no heat pumps that integrate various types of heat exchangers, such as clothes dryer, refrigeration, and domestic hot water, into a single integrated and centralized system. Traditionally, a dedicated refrigerant loop for effectuating a vapor- compression cycle is provided for each of the heat pump type appliances, such as HVAC systems, refrigerator, and clothes dryers of heat pump type. Users have to control operations of individual appliances separately, and must be mindful of the operating status of the appliances in order to save energy costs.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a centralized heat exchange system that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention is to introduce an integrated and centralized system and apparatus for a multi-function heat pump with multiple heat exchangers, such as domestic hot water, refrigeration, and clothes dryer.

Additional or separate features and advantages of the invention will be set forth in the descriptions that follow and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, in one aspect, the present invention provides a centralized heat exchange system for controlling a plurality of heat exchangers in a heat pump cycle, the centralized heat exchange system including: a plurality of heat exchanging units, each of the heat exchanging units being thermally coupled to a space/compartment adjacent thereto, and being configured to function as either a condenser or an evaporator permanently, or to function as a condenser or an evaporator interchangeably so that heat is transferred from or to the space/compartment; one or more of compressors; a network of refrigerant piping connected to each of the plurality of heat exchanging units and the one or more of compressors, at least one expansion valve in the network of refrigerant piping; at least one reversing valve in the network of the refrigerant piping; one or more sensors operably coupled to at least some of the spaces/compartments to be maintained at the same and/or different temperatures to which the corresponding heat exchanging units are respectively coupled, to measure one or more of thermodynamic state variables of the at least some of the spaces/compartments, the at least some of the spaces/compartments being defined as controlled spaces/compartments, at least two of the controlled space/compartments having respective heat capacities different from each other; and a controller configured to receive signals from the one or more sensors to monitor the one or more of thermodynamic state variables of the controlled spaces/compartments, the controller controlling the one or more of compressors, the at least one expansion valve, and the at least one reversing valve, wherein the controller is programmable to set respective target values for the one or more of thermodynamic state variables of the controlled spaces/compartments, and is also programmable to set a priority scheme for determining priorities for controlling the one or more of thermodynamic state variables of the controlled spaces/compartments, and wherein the controller controls the one or more of compressors, the at least one expansion valve, and the at least one reversing valve, to establish, in the network of refrigerant piping, one or more of a heat- pump loop that undergoes a vapor-compression cycle through an arrangement of a compressor, a condenser, an expansion valve, and an evaporator in series in accordance with the monitored one or more thermodynamic state variables, the target values and the priority scheme so that one or more among the controlled spaces/compartments are given higher priority in the control.

In another aspect, the present invention provides a centralized heat exchange system, including: a controller; one or more of compressors controlled by the controller; an outdoor heat exchanger that interchangeably operates as a condenser or an evaporator; an indoor heat exchanger that interchangeably operates as a condenser or an evaporator; a refrigerator for food storage, the refrigerator including an evaporator; a network of refrigerant piping connected to the one or more of compressors, the outdoor heat exchanger, the indoor heat exchanger, and the refrigerator; at least one expansion valve in the network of refrigerant piping; and at least one reversing valve in the network of the refrigerant piping, wherein the controller is connected to one or more user interface devices and to sensors that respectively monitor at least temperature of a space to be warmed or cooled by the indoor heat exchanger and a food compartment of the refrigerator, and wherein the controller controls the one or more of compressors, the at least one expansion valve, and the at least one reversing valve to establish, in the network of refrigerant piping, one or more of a refrigerant flow loop that undergoes a vapor-compression cycle through an arrangement of a compressor, a condenser, an expansion valve, and an evaporator in series in accordance with the monitored temperatures such that the refrigerator is given the highest priority in maintaining the temperature.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of refrigerant network coupled with multiple heat exchanging units according to an embodiment of the present invention. FIGs. 2A-2C show an example of control operation with certain priority setting according to an embodiment of the present invention.

FIGs. 3A-3C show an example of control operation with certain priority setting according to an embodiment of the present invention.

FIGs. 4A-4C show an example of control operation with certain priority setting according to an embodiment of the present invention.

FIG. 5 shows an example of control operation of a variable speed compressor used in an embodiment of the present invention.

FIG. 6 shows a block diagram illustrating control configuration according to an embodiment of the present embodiment.

DETAIL DESCRIPTIONS OF THE INVENTION

All illustrations of the drawings are for the purpose of illustrating embodiments of the present invention and are not intended to limit the scope of the present invention.

The present invention provides a centralized heat exchange system for controlling a plurality of heat exchangers in a heat pump cycle. In one aspect of the present invention, a compressor(s), multiple condensers, multiple evaporators, expansion valves, and a reversing valve(s) are connected in a single network of refrigerant piping, all of which are controlled by a controller. The controller also monitors the conditions of space/compartments for which at least some of the evaporators and the condensers are designed to regulate. Based on the monitored conditions, the controller appropriately controls the compressors and expansion valves (and other open/close valves, if any, in the network) to establish at least one heat-pump loop that is constructed by an arrangement of a compressor, a condenser, an expansion valve, and an evaporator within the network so that a particular compressor(s) or condenser(s) is given higher priority and operates in its optimum or near optimum operating condition. The controller performs this priority scheme based on user programmable or settable preference or factory- preset preference.

In more detail, a centralized heat exchange system according to one aspect of the present invention contains a plurality of heat exchanging units connected through a network of refrigerant piping. The term "heat exchanging unit" here is a genetic term that encompasses any one of a condenser, an evaporator, and a unit that can operate as a condenser or an evaporator interchangeably.

Examples of the heat exchanging units include an outdoor heat exchanger and an indoor heat exchanger with fans typically found in a HVAC system (each heat exchanger being interchangeably operable as a condenser or evaporator), an evaporator in a refrigerator and/or freezer, a condenser and an evaporator in a heat pump clothes dryer, a condenser and an evaporator respectively installed in a heat pump hot water reservoir or cold water reservoir, or the like. Tube and fin condenser coils and evaporator coils made of high heat conductivity materials are examples of commercially available heat exchanging units that can be used in the present invention. Heat exchanging units specifically designed for the present invention may be also utilized.

In the present invention, a network of refrigerant piping is disposed to connect all of these heat exchanging units. For each of the heat exchanging units, one or more of mechanical or electronic expansion valves are designated and installed in the refrigerant piping network.

The mechanical or electronic expansion valves may be any of commercially available thermal/electronic expansion valves having appropriate superheating capability. Expansion valves specifically designed for adoption to the present invention may also be utilized. In the alternative, or in addition, separate On/Off valves may be installed in the network to regulate the flow of the refrigerant. Since commercially available electronic expansion valves typically have the capability of completely shutting off the flow in addition to its superheating capability, the On/Off vales may not be needed when the electronic expansion valves are extensively utilized. As the expansion valves for the system, thermal expansion valves can also be used. However, when thermal expansion valves are employed, they may be accompanied by electrically controllable On/Off valves to provide for the shutoff function.

The present embodiment also includes one or more compressors in the network of the refrigerant piping for exerting pressure differentials to cause the refrigerant to flow in the network in a defined direction. The compressor(s) may be fixed speed, or variable speed, or may be a combination of any number of each. The compressors may be commercially available compressors, or those specifically designed to meet the requirements of the system may also be utilized. In the present embodiment, there is also provided one or more reversing valves in the network to reverse the flow direction of the refrigerant from the compressor in a selected segment(s) of the network such that the reversible heat exchangers (those which can be evaporators or condensers) can be switched. Any commercially available reserving valves that can be controlled by a controller can be utilized. A reversing valve may consist of two or more of electrically controllable simple On/Off valves with appropriate piping or can be an integrated reversing valve.

One or more sensors are also provided in the system to monitor thermodynamic state variables, such as temperature, pressure, humidity, etc., of the spaces or compartments to be controlled or maintained. For example, a room temperature sensor monitors the temperature of a room in which the indoor HVAC unit is installed. As is well known, temperature sensors are also installed in a refrigeration space and in a freezer to monitor the temperatures of respective compartments. For a hot water reservoir or cold water reservoir, the temperature of the stored water is monitored by an appropriate sensor. Various commercially available sensors can be used for these purposes. Digital sensors that can send signals corresponding to the measured thermodynamic state variables are preferred because they can digitally communicate with the system controller, which will be described below. Needless to say, various thermostat type devices can be used as the sensors.

In this invention, these spaces/compartments monitored by the sensors are referred to as "controlled spaces/compartments." In an indoor HVAC unit, the controlled space/compartment is a room in which the indoor heat exchange unit for the HVAC is installed. Refrigerator compartment and freezer compartments respectively correspond to the "controlled

spaces/compartments associated with the evaporator for the refrigerator and the evaporator for the freezer, and so on so forth. Spaces or compartments for which any of the thermodynamic state variables, such as temperature, are not monitored or controlled are non-controlled spaced/compartments. Outdoor space in which an outdoor heat exchanger for an HVAC unit is an example of non-controlled spaces/compartments

Any commercially available refrigerants can be used in the refrigerant piping. However, the refrigerant should be chosen to match the demands and other requirements of the controlled spaces/compartments, which should be regulated, with the performance capability of the compressor(s) and other thermodynamic parameters, such as conductivity of the piping, and the properties of the expansion valves, etc. A controller is provided to monitor and control the operations of the system of the refrigerant piping network having these components. In one embodiment, a controller may includes a CPU, memories, and other hardware, such as hard drives, EPROM, one or more of user-interface displays with virtual or actual keyboards, and is programmable by various known languages or preset programming procedures. The controller is connected in a wired or wireless manner to the compressor(s), each of mechanical or electronic expansion valves, and to any open/close valves, which may be installed in the refrigerant network, to control the flow and thermodynamic properties of the refrigerant therein. The controller also communicates with each of the sensors in wired or wireless manner to monitor the thermodynamic state variables, such as temperature, humidity, etc., and to display the current conditions of the

space/compartment (i.e., the "controlled space/compartment") on a sensor display, if equipped.

In one aspect of the present invention, the controller is programmable to set respective target values for the one or more of thermodynamic state variables of each of the controlled spaces/compartments, and is also programmable to set a priority scheme for determining priorities for controlling the one or more of thermodynamic state variables of the controlled spaces/compartments. The controller controls the compressor(s), the at least one expansion valve, and the at least one reversing valve, to establish, in the network of refrigerant piping, one or more of a heat-pump loop that undergoes a vapor-compression cycle through an arrangement of a compressor, a condenser, an expansion valve, and an evaporator in series in accordance with the monitored one or more thermodynamic state variables, the target values and the priority scheme so that one or more among the controlled spaces/compartments are given higher priority in the control. In the alternative to or in addition to the wired or wireless network of dedicated communication channels, these communications may be realized using the building's existing AC power wiring to send signals to each device. The controller also sends control signals to the compressor to determine the pressures and compressor speed required to meet the demands. The control algorithm also may include strategies for controlling fan speed of the outdoor unit and indoor space conditioning.

The priority scheme utilized in the controller can be factory-set, or user programmable, and may be configured so that the user can override or edit the algorithm as needed.

The controller makes decisions on which heat exchanging unit(s) should be operated in what order based on predetermined settings, thermodynamic properties, user preferences, importance of demands, and energy efficiency of different configurations. Then the controller sends signals to the expansion valves for each heat exchanger to allow the desired refrigerant flow. Refrigerant Piping Network Example

Various embodiments of the present invention are now described below with reference to the drawings. FIG. 1 shows a configuration of a centralized heat exchange system according to an embodiment of the present invention. As shown in FIG. 1, this example contemplates installation of the system in a household or business premises. The system has an outdoor component and indoor components. A network of refrigerant piping is shown in thick black lines in FIG. 1.

An outdoor heat exchanger XI is provided outside of the premises, such as outer space adjacent to the premises, or underground if the temperature is appropriate. The outdoor heat exchanger XI can be any of commercially available interchangeable condensers/evaporators as long as the demands imposed by the indoor components (described below) can be met. Or, it can be a proprietary outdoor heat exchanger specifically designed to meet the demands and other requirements imposed by a particular arrangement of the indoor components and the

environment in which the outdoor heat exchanger XI is installed. As is typical in the case of HVAC systems, in the alternative, the outdoor heat exchanger XI may be constituted of one or more dedicated outdoor evaporators as well as one or more dedicated outdoor condensers together with appropriate flow control valves, for example.

The system also includes an indoor heat exchanger X2 for heating and cooling a residential or commercial space. The indoor heat exchanger can be any of commercially available interchangeable condensers/evaporators as long as the demands for controlling the temperature of the room to be cooled and heated can be adequately met. Or, it can be a proprietary outdoor heat exchanger specifically designed to meet the demands and other requirements imposed by a particular arrangement and construction of the system and the heat capacity of the room to be heated or cooled by the unit. Or, the indoor heat exchange XI may be constituted of one or more dedicated indoor evaporators as well as one or more dedicated indoor condensers together with appropriate flow control valves, for example.

As shown in FIG. 1, the present embodiment further includes a hot water reservoir having a condenser CI for heating water; a heat pump dryer unit having a condenser C2 and an evaporator El; a chilled water reservoir having an evaporator E2; and a refrigerator having an evaporator E3. The refrigerator may include a freezer having a separate evaporator, of course. To sum, the overall system includes heat exchangers XI and X2; condensers CI and C2, and evaporators E1-E3 as the heat exchanging units. In this embodiment, for each of the heat exchanging units (heat exchangers XI and X2; condensers CI and C2, and evaporators E1-E3), an expansion valve (EV1 to EV 6) is installed.

The network of refrigerant piping also includes a compressor Com for exerting a pressure differential between its inlet and outlet in the refrigerant that goes therethrough to cause the refrigerant to flow in the pipe. The network also includes a reversing valve Rl installed adjacent to the compressor Com for reversing the direction of the refrigerant flow in a certain defined loop or loops. In particular, as shown in FIG. 1, in this embodiment, the reversing valve Rl can change the direction of the refrigerant flow in the loop constituted of the outdoor heat exchanger XI, the expansion valve EV1, the expansion valve EV6, and indoor heat exchanger X2 so that the heat exchangers XI and X2 operated as a pair of a condenser and an evaporator, respectively, in this order, or as a pair an evaporator and a condenser, respectively, in this order. For higher controllability and performance, a variable speed compressor is preferably used as the

compressor Com. Furthermore, one or more of additional compressors can be installed in series or in parallel in the network to supplement or enhance the pressurization of the refrigerant in particular segments of the piping. They may be fixed speed compressors, or more preferably, are variable speed compressors or a combination of both.

FIG. 6 shows a diagram illustrating a control configuration of the present embodiment. A controller 1 is provided to monitor and control the operations of the system of the refrigerant piping network having these components. In the present embodiment, a controller may include a CPU 11, memories 12, and other hardware, such as hard drives 13, EPROM, and a console 14 having one or more of user-interface, such as a liquid crystal display with virtual or actual keyboards, and is programmable by various known languages or preset programming procedures. The controller 1 is connected in a wired or wireless manner to the compressor(s) Com, each of mechanical or electronic expansion valves EV1 to EV6, and to any On/Off valves (open/close valves) that may be installed in the refrigerant network to control the flow and thermal properties of the refrigerant therein. The controller also communicates with each of sensors SEN1 to SEN5 to monitor the thermodynamic state variables, such as temperature, humidity, etc., and to display the current conditions of the space/compartment (i.e., the "controlled space/compartment") on the display in the central console 14 and/or on a display screen disposed adjacent to the controlled spaces/compartments monitored, if equipped, such as a thermostat display, or display on the front door of the refrigerator.

In one aspect of the present invention, the controller is programmable to set respective target values for the one or more of thermodynamic state variables of the controlled

spaces/compartments, and is also programmable to set a priority scheme for determining priorities for controlling the one or more of thermodynamic state variables of the controlled spaces/compartments. The operating software/algorithm containing such priority scheme as well as the user settable target temperatures or the like can be stored in memories in the controller 1, such as HD12, EPROM. The controller controls the compressor(s), the at least one expansion valve, and the at least one reversing valve, to establish, in the network of refrigerant piping, one or more of a heat-pump loop that undergoes a vapor-compression cycle through an arrangement of a compressor, a condenser, an expansion valve, and an evaporator in series in accordance with the monitored one or more thermodynamic state variables, the target values and the priority scheme so that one or more among the controlled spaces/compartments are given higher priority in the control.

In a perhaps simplest example, suppose that for given time in a day, among all of these controllable spaces/compartments, only the room inside the premises needs to be heated. Then, among all of the heat exchanging units X2, CI, C2, and E1-E3 inside the premises, only the indoor heat exchanger X2 needs to be operated (as a condenser). In such a case, the controller 1 instructs the expansion valve EVl to operate, closes down all other expansion valves (or control appropriate on/off valves), and instructs the reversing valves to operate so that the refrigerant flow in a loop in a direction of the compressor Com, the indoor heat exchanger (as a condenser) X2, the expansion valves EVl and the outdoor heat exchanger XI (as an evaporator) in this order.

Suppose further that even through the chilled water reservoir was not required to be monitored or regulated at that time (such as nighttime), but the temperature of the water in the reservoir was higher than the target temperature. In this situation, the controller 1 may use the evaporator E2 in the chilled water reservoir to operate as the evaporator for the heat-pump loop instead of the outdoor heat exchanger XI (as an evaporator). In such a case, the controller 1 instructs the expansion valve EV4 to operate, closes down all other expansion valves (or control appropriate on/off valves), and instructs the reversing valves to operate so that the refrigerant flow in a loop in a direction of the compressor Com, the indoor heat exchanger (as a condenser) X2, the expansion valves EV4 and the evaporator E2 in this order. In this case, because heat extracted from the chilled water container is utilized for heating the room indoor, resources are efficiently utilized; a typical heat pump would extract heat from the outdoors but in this case, heat is extracted from the water, effectively chilling the water for "free". At a given moment in time, the controller makes this type of decision based on the preset or programmable algorithm to achieve efficiency in energy usage. The actual efficiency and practicability of such a heat pump loop depend on the size and the heat capacity of the room to be heated, the size and the heat capacity of the chilled water reservoir, the characteristics of the evaporator E2 and the

characteristics of the outdoor heat exchanger XI (as the evaporator), etc. Furthermore, the loop involving the evaporator E2 may be established simultaneously with the loop involving the outdoor heat exchanger XI (as the evaporator) described above. This way, some of the heat needed to warm the room indoor can be transferred from the water container in the chilled water reservoir, thereby achieving efficient usage of energy. In this case, two parallel loops are established in the evaporator branch of the heat pump cycle. Since the physical properties, such as the conductivity of the fluid in the pipes contributing to these two loops, the relevant characteristics of the compressor Com, the heat exchanger XI and the evaporator E2, and the properties of the refrigerant are all known or designed or selected to have particular design characteristics, although the establishment and control of two or more of the loops in the network of the refrigerant piping require relatively complex calculation and algorithm, in appropriate circumstances, such as the above-mentioned situations, the system can have a plurality of such loops in order to increase energy efficiency and enhance effectiveness of required heating/cooling.

In another example, when the outside heat exchanger XI is operating as an evaporator, all or some of the condenser units (i.e., condensers CI and C2 and the indoor heat exchanger X2 as a condenser) can be simultaneously operated. And when the outside heat exchanger XI is operating as a condenser, all or some of the evaporator components (i.e., evaporators E1-E3 and the indoor heat exchanger X2 as an evaporator condenser) can be simultaneously operated.

More than one same type heat exchanging units may be in operation at the same time in this manner. However, this presupposes that the requirements for the multiple condensers

(evaporators) simultaneously operated have some degree of compatibility. In certain practical situations, this may not be possible or desired, which will be described below drawing examples. FIG. 5 is a flowchart showing an example of control operation of a variable speed compressor used in an embodiment of the present invention. In step S51, when a signal from the controller 1 indicates that the refrigerant is needed (i.e., some of the heat exchanging units need to be operated), the compressor Com is run at a nominal or preset speed initially (Step S52). If the temperature signals from any components indicate that the demand is not met, (Step S53), then the controller 1 increases the compressor speed by a requisite amount (Step S54). When the sensor determines that the demand is met, then the controller 1 decreases the compressor speed by a preset amount (Step S55). Then the process goes back to Step S53 to determine whether the temperature signals from any components indicate that the demand is not met. This exemplary scheme is applicable not only a single heat-loop configuration, but also multiple heat-pump loop configurations where two or more heat-pump loops are simultaneously established in the network.

There are other possible and practical ways and aspects in the control of the compressor. In one control strategy, the controller may detect which "low-side" components (i.e., any evaporator units) are turned on, and then modulates its speed to maintain the desired suction pressure. For example, if the refrigerator is needed and it has an evaporation temperature of -20°C, this corresponds to a particular pressure at which refrigerant evaporates at -20°C. The other devices like an evaporator for a space/room cooling unit might have an evaporation temperature of +5°C, so the compressor needs to match the lowest pressure of all the evaporators which are turned on. The compressor may perform such adjustment by increasing or decreasing the rpms. Another control strategy for the compressor may be a specific pre-programmed speeds set by the manufacturer such that when the controller detects that a particular combination of devices are turned on, it runs the compressor at one of the preset speeds, for example.

As demonstrated in the simple example above, the controller 1 can control the expansion valves EV1 to EV6 (and any On/Off valves, if any), the compressor Com, and the reversing valves Rl strategically based on a preset or programmable scheme/algorithm to establish a variety of loop configurations in the network of the refrigerant piping. In each of the established heat-pump loop, the condenser heats the corresponding space/compartments, and the evaporator extracts heat from the corresponding space/compartments. In a simple control scheme, the controller 1 may be configured to establish only a single heat-pump loop at a given point in time (or during a predetermined time interval), or depending on the monitored conditions of the controlled spaces/compartments, or depending on other factors, such as particular times in a day, or weekdays or weekends, the controller 1 may establish two or more heat-pump loops in the network. Thus, with a centralized control system according to this embodiment, there are numerous possibilities of controlling the heating/cooling requirements of various

spaces/compartments to achieve effective and energy-efficient heat pump operations.

Priority Scheme

In one aspect of the present invention, a controller controls each of the controllable constituent elements of the system so that control and regulation of one or more of the spaces/compartments to be monitored and controlled are given higher priorities than others.

For example, the room may require clothes drying at the same time as when the refrigerator requires cooling. In this case, the clothes dryer condenser C2 needs to be operated in a heat-pump loop that undergoes a vapor-compression cycle, and the evaporator E3 in the refrigerator needs to be activated in a heat-pump loop that undergoes a vapor-compression cycle. Such a combination of heat exchangers constitutes a significant amount of work for the compressor, possibly requiring more work than the compressor can produce. This is because the saturation temperature/pressure difference between the two components is extremely large. As an example, the refrigerator may have an evaporating temperature around -20 °C while the clothes dryer condenser may have a condensing temperature of 65 °C; this is a much large pressure difference than typical operation of the heat pump and requires considerable compressor power. To avoid this issue, the controller 1 may make a choice between the refrigerator cooling and clothes drying in order to operate more efficiently. If the refrigerator stores foods or other temperature sensitive substances, for example, then the controller 1 can be programmed or preset to give the refrigeration cooling higher priority in this situation. Thus, at least until the refrigerator reaches the desired target low temperature, the outdoor heat exchanger XI operates as a condenser that constitutes the heat-pump loop involving the evaporator E3 of the refrigerator. Once the refrigerator is sufficiently cooled to reach the target temperature, the clothes dryer can be operated in a loop with the condenser C2 and evaporator El as well as some excess flow to the outdoor heat exchanger XI (as an evaporator).

In another example, if several condensers (or evaporators) within the premises need to be operated at the same time and if the controller 1 is programmed to establish multiple heat-pump loops to activate these indoor multiple condensers (or evaporators), the controller 1 may drive the compressor Com under conditions optimized or nearly optimized for the particular one of the condensers (evaporators). For example, cooling in refrigerator may be given higher priority over chilled water reservoir, and therefore, the compressor Com can be operated at a speed optimum or near optimum for the refrigeration in the loops in the network. In another example, the heating by the indoor heat exchanger X2 (i.e., the condenser) can be given a higher priority over the heating of the water in the hot water reservoir (the condenser CI). In this case, the compressor Com is operated at a speed optimum or near optimum for the space heating. In both situations, the lower priority component(s) can be completely ignored such that the controller 1 only establishes the corresponding loop for the higher priority component (i.e., a loop for the refrigerator, but no loop for the chilled water reservoir until the refrigerator is sufficiently cooled; or, a loop for the indoor heat exchanger X2, but no loop for the hot water reservoir until the room is sufficiently heated). Specific examples of the priority control scheme are provided below.

FIGs. 2A-2C are a flowchart diagram showing an example of control operation with a certain priority scheme according to an embodiment of the present invention in the case of the network system shown in FIG. 1. The entirety of these processes is repeatedly performed at predetermined time intervals that can be preset or user adjustable (each constituting time steps). Examples of such predetermined time intervals include a few minutes, say, 5 to 15 minutes, so that the system can reach a relatively steady state and achieve good performance during the period. However, depending on the needs and the environment in which the system is operated, the time interval may be a fraction of a second to minutes, or much longer. Furthermore, the system can be configured such that the interval can be changed automatically depending on time in a day or the user can program desired intervals.

In decision box Ql, suppose that based on the reading/signal from the thermostat(s) or sensors installed in the premises, the controller 1 determines that cooling of the residence is needed. Referring to FIG. 2C, in the decision box Q3, the nature of low temperature side demands are analyzed by the controller 1. If chilled water (CW) is needed as well as space cooling and/or refrigeration, then the demand for cooling chilled water tank is ignored for this time step (S201). The controller 1 instructs the compressor Com to adjust compressor low-side pressure suitable for the refrigerator and runs the refrigerator at its max capacity (until next time-step) (S202). If the chilled water reservoir is connected to a piping to run the residence to cool the residence (optional), then the stored chilled water is used to cool the residence (assuming that the then temperature of the chilled water is lower than the room temperature) (S203).

In this example of the flowchart, if only the chilled water tank needs to be cooled in addition to space cooling, then space cooling is performed by the indoor heat exchanger X2 and the demand for the chilled water tank is ignored until the next time-step.

If the controller 1 determines that CW (chilled water) is not needed in Q3 and that both refrigerator and space cooling are needed at Q4, the refrigerator is given higher priority than the space cooling and the step S202 is executed.

Likewise, as shown in FIG. 2C, at Q3 and Q4, respective decisions/determinations are made, and depending on the determined needs, the refrigerator, space cooling by the indoor heat exchanger X2, and the heat exchanger unit (evaporator) of the chilled water reservoir (tank) are run respectively. See S204, S205 and S206 in FIG. 2C.

If the controller 1 determines that no cooling operations are necessary (based on the readings of the sensors or user input), it causes the outdoor heat exchanger XI to operate as an evaporator (since the outdoor heat exchanger need not be run as a condenser) (S207).

All of these various decision possibilities are processed at the controller 1, and the controller 1 sends out appropriate instructions signals or commands to respective thermal valves and the compressor Com to adjust the pressure of the refrigerant appropriately and establish the appropriate heat-pump loop in accordance with its decision (S208).

As seen above, among various components that can perform cooling, the refrigerator is given the highest priority in this example.

Referring to FIG. 2B, with respect to higher temperature demands, the controller 1 analyzes the status of the high-side demands at Q2. Depending on whether either or both of the clothes dryer and hot water reservoir need to be run, there are three branches of process to go through. Assuming that neither space cooling nor space heating is required, when both the clothes dryer and the hot water tank need to be run, the demand for the clothes dryer is temporarily ignored (S210), and the hot water tank is run until the demand is met (S211). If the water tank needs not to be run, then the clothes dryer is run (S212). If neither the hot water tank nor the clothes dryer is required to operate, the outdoor heat exchanger XI is operated as a condenser since no need to extract heat from the outside environment. Thus, in this branch, the hot water reservoir is given higher priority over the clothes dryer. All of these various decision possibilities are processed at the controller 1, and the controller 1 sends out appropriate instructions signals or commands to respective thermal valves and the compressor Com to adjust the pressure of the refrigerant appropriately and establish the appropriate heat-pump loop in accordance with its decision (S214).

In this example, the priority scheme can be configured such that if the refrigerator needs to be cooled, its takes the highest priority over everything else. This may be required when the refrigerator contains food or other temperature sensitive substances. For example, when the controller 1 determines that the refrigerator needs to be cooled, the compressor's low-side pressure is adjusted to that required for refrigeration. Even if the chilled water tank needs to be cooled, unless the refrigerator can be operated without compromise, the demand for cooling water in the chilled water reservoir can be ignored.

FIGs. 3A-3C are a flowchart diagram showing an example of control operation with a certain priority scheme according to an embodiment of the present invention in the case of the network system shown in FIG. 1. The entirety of these processes is performed repeatedly at predetermined time intervals (each constituting time steps) that can be preset or user adjustable. Examples of such predetermined time intervals include a few minutes, say, 5 to 15 minutes, so that the system can reach a relatively steady state and achieve good performance during the period. However, depending on the needs and the environment in which the system is operated, the time interval may be a fraction of a second to minutes, or much longer. Furthermore, the system can be configured such that the interval can be changed automatically depending on time in a day or the user can program desired intervals.

Suppose that the controller 1 learns based on the signals from the thermostat(s) or sensor(s) that space heating is needed within the residence at Q5 (FIG. 3A). If it is determined at Q7 (FIG. 3C) that both the hot water reservoir and the clothes dryer need to be operated, the demand for the clothes dryer is ignored (S301), and the high-side pressure of the refrigerant is adjusted to that required for hot water heating to run the hot water condenser coil in the hot water reservoir at maximum capacity for this time-step until the demand for hot water is met (S302).

If both the hot water tank/reservoir requires heating and the indoor heat exchanger H2 (as a condenser) need to be run, there are the following few control options, for example.

First, both the indoor heat exchanger (as a condenser) and the hot water reservoir can both be run. The compressor Com is controlled such that the high-side pressure of the refrigerant is adjusted to that optimized for the hot water reservoir, and the indoor heat exchanger X2 and the hot water reservoir are run simultaneously at the maximum capacity the system can provide. In this case, two heat-pump loops sharing the outdoor heat exchanger XI (as an evaporator) are established.

The second option is to run the hot water reservoir at its maximum capacity by ignoring the demand for the room heating until the water in the hot water reservoir is sufficiently heated (it does not take many time-steps to achieve the required heating), and then the space heating can be resumed thereafter.

If it is determined at Q7 (FIG. 3C) that heating of the water in the hot water reservoir is not needed, and if it is determined that both space heating and the clothes dryer are needed at Q8, there are a few options to take. Ideally, the dryer and the indoor heat exchanger X2 (as a condenser) should not be on simultaneously because they have different condensing

temperatures/pressures). If the system is designed so that these two do not operate

simultaneously, there are the following few control options to deal with this situation, for example.

As a first option, the demand for the clothes dryer is temporarily ignored, and only the space heating is performed by the indoor heat exchanger X2 (S303). The controller 1 adjusts the compressor speed to match the high- side pressure of space heating condenser to run space heating at maximum capacity for this time step to provide extra heating to the space temporarily until the room is heated to a target temperature or a temperature close to the target temperature. When the room is heated to such a temperature after a few or more time steps, the clothes dryer is operated (S304) for a certain predetermined period or until either the room temperature drops below a certain preset temperature, and then the space heating is again performed to meet the demand of the room heating. The system continues to operate in such a manner alternating between the two devices every time step or every predetermined number of time steps, for example.

The second option is that the clothes dryer is run and hot water contained in the hot water reservoir is used to space heating (if the hot water reservoir is connected to piping of hot water for the purpose of the space heating). In this case, the compressor's high-side pressure is adjusted to match the clothes dryer condenser pressure to run the clothes dryer (FIG. 3C, S303).

If it is determined at Q8 that only space heating is needed (i.e., neither the clothes dryer nor hot water are needed), only the indoor heat exchanger X2 is operated as a condenser (S305). To this end, the high-side pressure of the refrigerant is adjusted to that for the indoor heat exchanger as a condenser to cause the refrigerant to flow through space heating condenser at designed capacity until the target temperature is reached

If no heating device is found to be needed at Q7, the outdoor heat exchanger is operated as a condenser (since there is no need to extract heat from the outdoor) (S306).

For the low side demands, as shown in FIG. 3B, depending on the demands of the respective cooling devices, each cooling device is operated accordingly, with the refrigerator given the highest priority. See S309 to S313 in FIG. 3B.

In case that the refrigerator contains food or other temperature critical substances, the system can be configured such that the refrigerator control has the highest priority over any other processes depicted in FIGs. 3A-3C.

All of these various decision possibilities shown in FIGs. 3A-3D are processed at the controller 1, and the controller 1 sends out appropriate instructions signals or commands to respective thermal valves and the compressor Com to adjust the pressure of the refrigerant appropriately and establish the appropriate heat-pump loop in accordance with its decision (S308 in FIG. 3C and S314 in FIG. 3B).

FIG. 4A-4C show an example of control operation with certain priority setting according to another embodiment of the present invention. In this embodiment, the highest priority is placed on the refrigerator control expressly, and various lower priority control is specified.

As shown in FIG. 4A, the system first determines whether the refrigerator needs cooling (A2) and if the refrigerator needs cooling, the refrigerator is operated (A3). Subsequently, the demands for space cooling, water cooling/heating, and clothes dryer operation are examined in series (A4, A5, A6, A9, and Al 1). The system is configured such that cold water in the cold water reservoir can be circulated through the piping that runs through the premises so that the cold water can be used for space cooling (A8). Also, the clothes dryer is connected to the hot water reservoir/tank so that the residual heat generated by the clothes dryer (A9) can be dumped to the hot water tank (A10, A13). As indicated in A14, the remaining excess high side load is rejected through the outdoor condenser, and the remaining excess cooling load is coupled to the cold water reservoir so that the system can efficiently utilize the heat generated/extracted through the heat-pump cycle.

As shown in FIG. 4B, if it is determined that the space cooling is not required at A4, the needs for space heating, water heating, and clothes dryer operation are examined in steps A15 to A 17. Depending on the needs, one or more of the clothes dryer, the space heating condenser (corresponding to the indoor heat exchanger X2 in FIG. 1), and the chilled water reservoir are run (A 18 to A20).

If the water heating is not required at A 16, depending on whether the clothes dryer needs to be operated (A21), operations depicted in A22 or A23 are performed. If it is determined that space heating is not required at A15, as shown in FIG. 4C, the system recognizes no space heating/cooling is required (A24). Then the needs for water heating, clothes dryer operation are determined (A25 and A27), and the operations designated in A26 and A28-A30 are performed respectively depending on the determinations.

Thus, in this embodiment, the highest priority for control is given to control of the refrigerator, and other components/appliances are given varying degrees of priorities depending on the demands.

As described above to certain extent, in one aspect of the present invention, the present invention provides a multi-function heat pump with domestic hot water, refrigeration, and clothes dryer integration which refers to a system capable of operating and controlling some or all of a plurality of heating and cooling needs within a residence, building, or other space. In this aspect, the present invention includes a control algorithm to allow the system to perform clothes drying and refrigeration functions.

The present invention also allows for integration with a plurality of renewable energy sources, integration with the smart grid, a home automation system, and can potentially significantly increase energy efficiency. For example, the controller 1 of the above-mentioned embodiments can monitor electricity usage and can be connected to a smart grid so that the information on the electricity usage and status of the local electricity grid can be taken into account in its control decision algorithm/priority scheme.

As described above to certain extent, embodiments of the present invention may include one or more of the following features:

1. Providing space cooling and/or heating to a residence

2. Providing refrigeration for food storage 3. Performing the function of a typical residential clothes dryer

4. Heating and storing hot water for domestic use

5. Cold water storage

6. Ventilation air conditioning

8. Utility/smart grid access for demand management to dump excess load from grid into storage

9. Thermal storage for renewable energy produced on site.

As described above to certain extent, an embodiment of the present invention may include the following components:

1. An outdoor heat exchanger which may either transfer heat between outside air and refrigerant and/or between an underground fluid loop and refrigerant (air source and/or ground source) and/or solar panels.

2. Any number of indoor evaporator coils to provide space cooling and/or ventilation to the residence via heat transfer with refrigerant.

3. Any number of indoor condenser coils to provide space heating to the residence via heat transfer with refrigerant, and/or

2b/3b. Any number of heat exchanger coils which may act with refrigerant flow in either direction to achieve heating or cooling within a space and/or water heating and/or water cooling for thermal storage purposes.

4. Any number of radiant heating and/or cooling loops within floors, ceilings, or walls of a residence which transfer heat between refrigerant, water, or another fluid and a room. 5. One or more refrigerator and/or freezer apparatuses specifically designed to connect to the preferred embodiment of the present invention, or

5b. One or more apparatuses or processes which allow an existing refrigerator to be retrofitted for connection to the present invention.

6. One or more clothes dryers (and/or other appliances such as dish washers and clothes washers) designed specifically to connect to the present invention containing both an evaporator and condenser, or:

6b. One or more apparatuses or a processes which allows an existing clothes dryer to be retrofitted for connection to the present invention.

7. One or more hot water storage tanks designed specifically for use with the present invention which stores and heats water via heat transfer with refrigerant. The present invention also has the ability to monitor water temperature and stored volume or mass.

7b. One or more apparatuses or a process which allows an existing hot water tank to be retrofitted for use with the present invention.

8. One or more apparatuses capable of chilling and storing water, monitoring water temperature, and quantity.

9. At least one mechanical or electrical expansion valve for each one of the above heat exchangers to control the refrigerant flow and properties throughout the system.

10. A minimum of one compressor with variable speed and/or variable displacement control.

11. Any number of thermostat devices for determining indoor temperatures and accepting user inputs for comfort levels. 12. An electronic control system to regulate the vapor compression cycle in order to maintain indoor comfort levels, hot water availability, safe food storage, and functionality of any and all other processes connected to the invention.

13. A network of refrigerant piping to connect the components of the vapor compression cycle.

14. Any refrigerant.

As described above, FIG. 1 shows connections of refrigerant lines, which make up a vapor compression cycle, as a mere one example of embodiments of the present invention. Many other configurations not shown here are nevertheless part of the present invention as described above and as set forth in the appended claims.

As described above, embodiments of the present invention include a main controller. The main controller of the system receives inputs from temperature sensor(s), which monitor the refrigerator and freezer temperature, the temperature within the chilled water tank, the temperature within the hot water tank, and the temperature within any number of rooms within the residence. Additional sensors monitor water levels of hot and cold water in their respective storage tanks. The controller also may receive user inputs for clothes dryer operation and set point temperatures for heating and cooling.

Embodiments of the present invention may also include additional control algorithms that can be utilized to achieve any or all of the following features:

• coupled to the utility/smart grid access for demand management to dump excess load from grid into appropriate storage

• coupled to thermal storage for renewable energy produced on site • integrated with a home automation system for comprehensive centralized control.

• settable or predetermined priorities to use stored water for space heating/cooling during peak hours

It will be apparent to those skilled in the art that various modification and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover modifications and variations that come within the scope of the appended claims and their equivalents. In particular, it is explicitly contemplated that any part or whole of any two or more of the embodiments and their modifications described above can be combined and regarded within the scope of the present invention.

Claims

What is claimed is:

1. A centralized heat exchange system for controlling a plurality of heat exchangers in heat pump cycle, the centralized heat exchange system comprising:

a plurality of heat exchanging units, each of the heat exchanging units being thermally coupled to a space/compartment adjacent thereto, and being configured to function as either a condenser or an evaporator permanently, or to function as a condenser or an evaporator interchangeably so that heat is transferred from or to the space/compartment;

one or more of compressors;

a network of refrigerant piping connected to each of said plurality of heat exchanging units and said one or more of compressors,

at least one expansion valve in the network of refrigerant piping;

at least one reversing valve in the network of the refrigerant piping;

one or more sensors operably coupled to at least some of the spaces/compartments to be maintained at the same and/or different temperatures to which the corresponding heat exchanging units are respectively coupled, to measure one or more of thermodynamic state variables of said at least some of the spaces/compartments, said at least some of the

spaces/compartments being defined as controlled spaces/compartments, at least two of said controlled space/compartments having respective heat capacities different from each other; and a controller configured to receive signals from said one or more sensors to monitor said one or more of thermodynamic state variables of said controlled spaces/compartments, the controller controlling said one or more of compressors, said at least one expansion valve, and said at least one reversing valve, wherein the controller is programmable to set respective target values for said one or more of thermodynamic state variables of said controlled spaces/compartments, and is also programmable to set a priority scheme for determining priorities for controlling said one or more of thermodynamic state variables of said controlled spaces/compartments, and

wherein the controller controls said one or more of compressors, said at least one expansion valve, and said at least one reversing valve, to establish, in said network of refrigerant piping, one or more of a heat-pump loop that undergoes a vapor-compression cycle through an arrangement of a compressor, a condenser, an expansion valve, and an evaporator in series in accordance with the monitored one or more thermodynamic state variables, said target values and said priority scheme so that one or more among said controlled spaces/compartments are given higher priority in the control.

2. The centralized heat exchange system according to claim 1, wherein said

thermodynamic state variables are temperature, pressure, and humidity.

3. The centralized heat exchange system according to claim 1, wherein said plurality of heat exchanging units include an outdoor heat exchanger that interchangeably operates as a condenser or an evaporator.

4. The centralized heat exchange system according to claim 3, wherein said plurality of heat exchanging units further includes an indoor heat exchanger that interchangeably operates as a condenser or an evaporator.

5. The centralized heat exchange system according to claim 4, wherein said plurality of heat exchanging units further includes a refrigerator for food storage, the refrigerator including an evaporator and a compartment coupled to said evaporator to store food as said

space/compartment associated therewith.

6. The centralized heat exchange system according to claim 5, wherein said plurality of heat exchanging units further includes a clothes dryer including a condenser and an evaporator.

7. The centralized heat exchange system according to claim 6, wherein said plurality of heat exchanging units further includes at least one of a heat pump water heater having a condenser, a hot water storage tank for heating having an condenser, and a chilled water storage tank for cooling having an evaporator.

8. The centralized heat exchange system according to claim 4, wherein said indoor heat exchanger is an HVAC unit.

9. The centralized heat exchange system according to claim 4, wherein said plurality of heat exchanging units further includes at least one of:

a refrigerator for food storage, the refrigerator including an evaporator and a

compartment coupled to said evaporator to store food as said space/compartment associated therewith;

a clothes dryer including a condenser and an evaporator;

a heat pump water heater having a condenser; a hot water storage tank for heating having a condenser; and

a chilled water storage tank for cooling having an evaporator.

10. The centralized heat exchange system according to claim 5, wherein said priority scheme places the highest priority to control of the refrigerator.

11. The centralized heat exchange system according to claim 5, wherein said plurality of heat exchanging units further includes a freezer for food storage having an evaporator, and wherein said priority scheme places the highest priority to control of the refrigerator and the freezer.

12. The centralized heat exchange system according to claim 1, further comprising one or more of thermal storage units, said thermal storage units being capable of retaining heat accumulated or extracted therein or maintaining a high or low temperature state by way of phase transition,

wherein the controller determine whether to establish and maintain one or more of said heat pump loop that undergoes a vapor-compression cycle based on a status of said thermal storage units.

13. The centralized heat exchange system according to claim 12, wherein said one or more of thermal storage units include a hot water storage for heating a household, and wherein the controller further monitors electricity usage in the household and determines not to establish or maintain a heat-pump loop in the network of refrigerant piping based on the monitored electricity usage and a status of the hot water storage.

14. The centralized heat exchange system according to claim 12, wherein said one or more of thermal storage units include a chilled water storage for cooling a household, and

wherein the controller further monitors electricity usage in the household and determines not to establish or maintain a heat-pump loop in the network of refrigerant piping based on the monitored electricity usage and a status of the chilled water storage.

15. The centralized heat exchange system according to claim 12, wherein said one or more of thermal storage units include an ice maker and storage unit for cooling a household, and wherein the controller further monitors electricity usage in the household and determines not to establish or maintain a heat-pump loop in the network of refrigerant piping based on the monitored electricity usage and a status of the ice maker and storage unit.

16. The centralized heat exchange system according to claim 1, further comprising a power generator for producing electric power for a household or to an electricity grid,

wherein wasted heat generated by said power generator is utilized to heat or cool a household

wherein the controller determine whether to establish and maintain one or more of said heat pump loop that undergoes a vapor-compression cycle based on a status of the household heated or cooled by said wasted heat.

17. The centralized heat exchange system according to claim 1, wherein said one or more of the compressors include a variable speed compressor, and the controller controls the speed of the variable speed compressor.

18. The centralized heat exchange system according to claim 1, further comprising at least one of an electric water heater and a gas-fired water heater, controlled by the controller.

19. A centralized heat exchange system, comprising:

a controller;

one or more of compressors controlled by said controller;

an outdoor heat exchanger that interchangeably operates as a condenser or an evaporator; an indoor heat exchanger that interchangeably operates as a condenser or an evaporator; a refrigerator for food storage, the refrigerator including an evaporator;

a network of refrigerant piping connected to said one or more of compressors, said outdoor heat exchanger, said indoor heat exchanger, and said refrigerator;

at least one expansion valve in the network of refrigerant piping; and

at least one reversing valve in the network of the refrigerant piping,

wherein the controller is connected to one or more user interface devices and to sensors that respectively monitor at least temperature of a space to be warmed or cooled by the indoor heat exchanger and a food compartment of the refrigerator, and

wherein the controller controls said one or more of compressors, said at least one expansion valve, and said at least one reversing valve to establish, in said network of refrigerant piping, one or more of a refrigerant flow loop that undergoes a vapor-compression cycle through an arrangement of a compressor, a condenser, an expansion valve, and an evaporator in series in accordance with the monitored temperatures such that the refrigerator is given the highest priority in maintaining the temperature.

20. The centralized heat exchange system according to claim 19, further comprising a clothes dryer including a condenser and an evaporator both connected to the network of refrigerant piping.

21. The centralized heat exchange system according to claim 20, further comprising a heat pump water heater including a condenser connected in the network of refrigerant piping.

22. The centralized heat exchange system according to claim 19, wherein said one or more of the compressors include a variable speed compressor, and the controller controls the speed of the variable speed compressor.

23. The centralized heat exchange system according to claim 19, further comprising at least one of an electric water heater and a gas-fired water heater, controlled by the controller.