THERMAL HUB SYSTEM FEATURING REFRIGERATION

FIELD OF THE APPLICATION

The present application relates to refrigeration systems used in industrial refrigeration applications and to efficient uses thereof.

BACKGROUND OF THE ART

Industrial-size refrigeration systems are used in numerous applications. For example, supermarkets, sporting facilities, industrial cooling facilities are among the numerous instances in which central refrigeration systems are used. The central refrigeration systems may be used for refrigerating foodstuff, for operating freezers, for maintaining ice-playing surfaces (also known as ice sheets).

In such industrial-size refrigeration systems, the condensing stage must release substantial amounts of heat from compressed refrigerant, as part of the thermodynamic cycle, to enable the refrigerant to absorb heat in refrigeration duties. As global climate concerns have driven requirements for more efficient energy consumption, refrigeration systems may be regarded as being inefficient due to the amount of heat that is exhausted to the environment, in spite of efforts to reclaim the heat in the condensing stage. Stated differently, heat may not be optimally reclaimed in some industrial-size refrigeration systems, for example due to a mismatch between refrigeration load and heat demand. Moreover, with carbon taxes that may come into force in some regions, there is pressure on operators of such system to optimize energy consumption.

SUMMARY OF THE APPLICATION

It is therefore an aim of the present disclosure to provide a refrigeration system that addresses issues associated with the prior art.

In a first aspect, there is provided a system for operating a refrigeration system, comprising: a processing unit; and a non-transitory computer-readable memory communicatively coupled to the processing unit and comprising computer-readable program instructions executable by the processing unit for: operating a main refrigeration circuit as a function of a cooling load of an evaporation stage of a first facility; reclaiming heat from the main refrigeration circuit to provide heat to at least a second facility separate from the first facility in response to at least two concurrent heat demands for at least the second facility; and storing cold heat or hot heat as a function of a difference between the heat reclaimed and the cooling load.

In a second aspect, there is provided a thermal hub comprising: a main refrigeration circuit including at least a compression stage, a condensing stage, and an evaporation stage, a refrigerant circulating between the compression stage, the condensing stage and the evaporation stage in a refrigeration cycle; at least one refrigeration load facility in heat exchange relation with the main refrigeration circuit to receive cold from the evaporation stage in a response to a cooling load demand; at least one occupant building in heat exchange with the main refrigeration circuit to receive heat from the condensing stage in response to at least two concurrent heat demands, the heat demands different from one another; at least one heat sink in heat exchange with the main refrigeration circuit to receive, store and release cold heat or hot heat; and a controller unit configured for operating the main refrigeration circuit and the at least one heat sink to satisfy heat or cold demand of the at least one refrigeration load facility, of the at least one occupant building.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a thermal hub relative to an exemplary occupant building, a refrigeration load facility and a heat sink;

FIG. 1B is a block diagram showing the thermal hub of FIG. 1A, along with contemplated demands for heat;

FIG. 2 is a block diagram of the thermal hub of FIG. 1A, relative to the occupant building, refrigeration load facility and heat sink;

FIG. 3 is a block diagram showing a mode of operation of the thermal hub of FIG. 1A;

FIG. 4 is a block diagram showing a mode of operation of the thermal hub of FIG. 1A;

FIG. 5 is a block diagram showing a mode of operation of the thermal hub of FIG. 1A; and

FIG. 6 is a block diagram showing a mode of operation of the thermal hub of FIG. 1A.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1A, a thermal hub in accordance with an aspect of the present disclosure is generally shown at 10. The thermal hub 10 is used to meet a cooling demand of a refrigeration load(s), while providing heat to satisfy a heat demand. For example, the heat demand may be a plurality of heat demands, that may be combined as a total head demand of a building, a district, etc. For simplicity, the expression “heat demand” will be used herein, but may be regarded as a plurality of different heat demands, as exemplified herein, i.e., a global heat demand, a total heat demand. The individual heat demands may vary in terms of temperature, in terms of amount of energy, in terms of power flux, etc. The thermal hub 10 may balance the cooling demand and the heat demand by operating a thermodynamic cycle in which an aim may be to offset the cooling demand with the heat demand, so as to reduce energy losses of a thermodynamic cycle. The thermal hub 10 is therefore operated with a refrigeration load facility (ies) 20 and an occupant building(s) 30. Optionally, one or more heat sinks 40 may be present to store heat or cold, as part of an effort of the thermal hub 10 to use energy efficiently, and minimize heat released to the environment as part of the thermodynamic cycle.

The thermal hub 10 is depicted in relation to a refrigeration load facility 20. The refrigeration load facility 20 may be any type of facility (ies) that has a relatively high refrigeration demand, such as refrigeration demand that exceeds HVAC of an office tower, or a refrigeration demand that is not strictly seasonal, unlike air conditioning in the summer. For example, the refrigeration load facility 20 is a supermarket(s) or like food market that has one or more refrigerated cabinets and/or enclosures, for refrigerating and/or freezing foodstuff. Typically, a food market, also known as a grocery store, operates refrigerators (about 35° F.) and freezer (below 32° F.). Accordingly, the refrigeration load facility may have different refrigeration load demands, in an example. As another example, the refrigeration load facility 20 may be a sporting facility, in which the refrigeration demand is for maintaining one or more ice-playing surfaces (also known as ice sheets). As other examples of industrial cooling facilities, industrial refrigeration warehouses are among the numerous instances in which a high refrigeration demand is prevalent, yet other types of refrigeration load facilities are considered as well. The refrigeration load facility 20 may include more than one such facility, building, etc. The refrigeration load facility 20 may also be an outdoor ice sheet(s), that may be operated during the colder months of the year.

The thermal hub 10 is also shown relative to an exemplary occupant building 30. The occupant building 30 is shown as a tower in FIG. 1A, of the type that may have numerous occupants simultaneously. For example, the occupant building 30 may be an apartment building, a hotel, a condominium tower, and/or any other building that serves as housing, whether temporary or permanent. The occupant building 30 may have a combination of such housing capacities, such as in the case of a condo-hotel, a time-sharing unit, etc.

The occupant building 30 may also be of the commercial type, such as an office tower, in which workers are present for example in day jobs, night jobs, etc. The occupant building 30 may have office space and housing, in a multi-purpose configuration. The occupant building(s) 30 may be described as being independent from the refrigeration load facility 20, in that the occupant building(s) 30 is not a building that is primarily destined to accommodate the crowd associated with an event at the refrigeration load facility 20, e.g., the occupant building 30 is not the arena in which spectators gather to watch an event on ice, in which players participate in the event, etc. The occupant building 30 may not be ancillary to the refrigeration load facility 20.

While the occupant building 30 is shown as a single building, the occupant building 30 may include multiple buildings, such as a condominium or apartment complex. Moreover, the occupant building 30 may be defined by or may include individual housing units, such as single-family houses, plex-type buildings (e.g., duplex, triplex, etc.). The occupant building 30 may be a mixture of various types of such buildings, such as an office tower(s), apartment building(s), houses, plex-type buildings. In a variant in which multiple buildings are present, the occupant building 30 may be a block(s), a district, a suburb, a town. The occupant building 30 could be an industrial facility, for example for industrial processes. In an instance, the industrial facility is a plant that operates a process(es) requiring heat, such as manufacturing process, food process, etc.

One possible relation between the thermal hub 10 and the occupant building 30 is one in which the thermal hub 10 provides district heating to the occupant building 30. District heating may be described as distributing heat that is generated at a central location, such as at the thermal hub 10, through a heat exchange pipe network, to a plurality of a building or buildings occupied by a plurality of occupants. Another possible relation is that of district cooling, or of both district heating and district cooling. District heating and district cooling may be know as being a district thermal energy network, by which energy is distributed to numerous buildings (e.g., houses, apartments, condos) of a district, with some of the buildings for example being physically separated.

The heat sink 40 has heat storage capacity, whether it be for storing cold heat or hot heat. For example, the heat sink 40 may be one or more of a geothermal well. The expression “cold heat” is used to express the notion of cooling, such as in instances when heat is absorbed. For example, when cooling an ice sheet, it may be said that “cold heat” is provided to the ice sheet, while in reality the cold heat represents an absence of heat, or a lower heat level in comparison to another fluid, such as the water or like liquid used for the ice sheet. The water may be warmer than the refrigerant for the refrigerant to absorb heat from it, whereby the expression “cold heat” may be used. The geothermal well stores heat in the ground, by way of a coolant that exchanges heat (cold or hot) between the thermal hub 10, refrigeration load facility 20 and/or occupant building 30, and the ground. For example, cold is stored in the geothermal well 40 in winter, and is used for cooling in the summer. While a seasonal approach is described, a shorter-term cycle is also contemplated for the geothermal well 40. Other examples of heat sinks 40 may include an ice battery, and a body of water, such as a pond, a lake, etc, and any combination thereof. In a variant, the refrigeration load facility 20, the occupant building 30 and the heat sink 40 are part of a same property, with the heat sink 40 for example being a lake, pond or sewer system, provided environmental studies have been conducted to ensure that the use of such heat sinks 40 does not have any detrimental effect on the environment and/or on the wildlife. The heat sinks 40 could be useful or non-useful (rejection of heat to air, water, sewers, ground). The heat sinks 40 may be selected to change phase at selected temperatures, to increase latent heat storage.

The heat sink 40 has the ability to absorb or reject heat. A heat sink may be an unlimited reservoir where heat can be absorbed or rejected indefinitely, or it may be a limited reservoir where heat can be temporarily accumulated or removed. Some heat sinks like the atmosphere or an open source of water are essentially unlimited storage, able to absorb heat from or reject heat to without any rise or drop in temperature. Others like an ice battery have a defined heat storage capacity and can store heat for later removal. Still others like a geothermal field may if very large act like an unlimited reservoir, but more typically act like a limited reservoir that will increase and decrease in temperature if the heat in rejected or removed from the reservoir.

In FIG. 1A, there is shown that a direct thermal transfer relation may exist between the heat sink 40, the refrigeration load facility 20 and/or the occupant building 30. For example, a coolant piping network may extend between these entities, with heat exchangers at ends of the pipes of the network, to displace heat from one entity to another. In some instances, the refrigerant used in the refrigerant cycle operated by the refrigeration load facility 20 may be circulated in the occupant building(s) 30 and/or the heat sink 40. As an example, a heat exchanger may bring heat from the heat sink 40 to a heat sink in the occupant building 30, which heat sink in the occupant building 30 may be part of an internal piping network to feed a pulsed air ventilation system, as an example among others. A similar arrangement may be between the heat sink 40 and the refrigeration load facility 20. In an arrangement, the heat sinks 40 are in the refrigeration load facility 20 and/or in the occupant building 30. Numerous components may be present to enable the use of heat to satisfy heating or cooling demands, such as valves, conduit or pipe networks, pumps, heat exchangers, receivers, to name a few. As explained below, the components may be operated centrally by a controller unit that drives the operation of the thermal hub 10 holistically with a view to reduce energy losses.

Referring to FIG. 1B, the thermal hub 10 is shown being a unit having compressors, condensers, evaporators, to satisfy heating demand and cooling demand, and in relation with the heat storage, source or sink. Various examples are given of high-grade heat demand, medium-grade heat demand, low-grade heat demand, and cooling demand. The examples given in FIG. 1B are merely examples in which an ice rink(s) is present. However, the thermal hub 10 could be used with other refrigeration loads, such as HVAC, industrial cooling, industrial processes, indoor skiing facilities, etc. The thermal hub 10 may be said to have a single refrigerant in a single circuit system, as opposed to having a plurality of isolated individual refrigeration systems each operating its own refrigeration cycle. The refrigerant may be any appropriate type of refrigerant, including ammonia, carbon dioxide (CO₂), synthetic refrigerants, etc.

Referring to FIG. 2, the thermal hub 10 in accordance with the present disclosure is illustrated at 10, and is provided as a simple and generic example. The thermal hub 10 may have numerous other features, some of which are described hereinafter. The thermal hub 10 may also be referred to as a refrigeration system 10, as a power plant 10. The thermal hub 10 may have a conventional refrigeration circuit (also referred to as main refrigeration circuit) featuring a compression stage 11, a condensing stage 12, an expansion stage 13 and/or an evaporation stage 14. The refrigeration system 10 may have a single refrigerant undergoing a refrigeration cycle.

Refrigerant enters compressor(s) in the compression stage 11 as a saturated vapor and is compressed to a higher pressure and temperature. The refrigerant may be any appropriate type of refrigerant, including ammonia, carbon dioxide (CO₂), synthetic refrigerants, etc, but with a single one being used. In a variant, the compression stage 11 has numerous compressors in parallel and/or cascaded, such as two or more stages of compressors, such as in a pool of compressors. The compressed refrigerant vapor is then routed to the condensing stage 12 where it is cooled and optionally condensed into a liquid by flowing through a condenser unit(s), in which the refrigerant circulates through coils with a coolant such as cooling water or cooling air flowing across the coils, whereby the circulating refrigerant rejects heat from the main refrigeration circuit, the rejected heat being carried away by either the liquid (e.g., water, glycol) or the air (or like gas coolant) depending on the type of condenser unit used, as described below. The thermal hub 10 aims to reclaim as much heat as possible in the condensing stage 12, as opposed to releasing the heat to the environment. While the expression “condensing” is used to describe the stage 12, in line with notions of a thermodynamic refrigeration cycle, there may be limited to no condensing occurring in stage 12, for example as a function of the type of refrigerant that is being used. The expression “condensing stage 12” is deemed to encompass herein a stage where the refrigerant worked in the compression stage 11 releases heat, for instance in a reclaim or recuperation manner, and/or in a gas cooling manner, in addition to a possible condensing of refrigerant.

In essence, a condenser unit is where a vapor refrigerant is condensed into a liquid refrigerant. However, depending on the nature of the refrigerant, the condensing stage 11 may also be a stage where the refrigerant remains in a gaseous state, yet is cooled down. This may be the case when the refrigerant in the thermal hub 10 is carbon dioxide. It may be referred to as gas cooling, even though it occurs in the condensation stage 12. The condensing stage 12 also includes heat reclaim. By heat reclaim, heat is recuperated for various uses associated with the refrigeration load facility 20, the occupant building(s) 30, and/or the heat sink 40. In a variant, heat is recuperated in such a way that two or more heat demands are satisfied, with the head demands having different requirements relative to one another. For example, one of the heat demand may required medium-grade heat while another may require high-grade heat, as described below.

Different types of condenser units may be used as part of the condensing stage 12, with one or more condenser unit in the refrigeration system 10, such as air-cooled condenser units, gas coolers, evaporative condenser units, and water-cooled condenser units. The condensation stage 12 is shown generally, but may have different components (e.g., different valves, coils, length of coils) in different arrangements, such as heat exchangers used in heat reclaim, in parallel and/or in series with condenser units that reject heat to the environment (if any). In a variant, the amount of heat released to the environment is maintained at a minimum, in an effort of the thermal hub 10 to recuperate as much heat as possible, for instance for the district heating of the occupant building(s) 30. In a variant, the different types of components, the different arrangements, the different configurations allows different heat demands to be satisfied in the condensing stage 12, via heat reclaim. This is for example illustrated in FIG. 2, in which the condensing/reclaim stage 12 is shown having a plurality of reclaim units, shown as R1, R2, R3, R4 and R_n, although more or fewer may be present. It is these reclaim units R and their arrangement in the refrigeration system that enable the reclaim of heat according to heat demand requirements. For example, R1 may have the capacity of reclaiming high-grade heat, while R2 may reclaim low-grade heat, with for example R3 having a greater total heat reclaim capacity than R4, etc.

The condensing liquid refrigerant may then be accumulated in one or more receivers (not shown). The receiver(s) is one or more storage vessels (i.e., tank, reservoir) in which the refrigerant is stored mostly in a liquid state, with vapour. The condensed liquid refrigerant may next be directed through an expansion stage 13 in which valve(s) of any type, such as expansion valves, causes a reduction in pressure to the refrigerant. Other mechanisms and configurations may also be used, including flooded configurations with a pump or pumps, such that the expansion stage 13 may be optional. The pressure reduction results in a lowering of the temperature of the refrigerant to reach a temperature colder than the temperature of the fluid, space and/or surface to be refrigerated.

The cold refrigerant is then circulated in the coil or tubes of evaporator(s) of the evaporation stage 14, by which the cold refrigerant absorbs heat from a fluid, such as a liquid or a gas depending on the application with which the thermal hub 10 is used. The evaporation stage 14 is where the refrigerant absorbs and removes heat that is subsequently rejected or reclaimed in the condensing stage 12. The coils of the evaporation stage 14 may be part of refrigerated enclosures (e.g., freezers and/or refrigerators), such as in supermarket of the refrigeration load facility 20, in a slab(s) of an ice sheet of the refrigeration load facility 20, etc. As another possibility, the coils of the evaporation stage 14 are part of a heat exchanger, with the refrigerant of the thermal hub 10 being in heat exchange with a coolant (e.g., glycol, brine). In an embodiment, the coolant circulates in coils of an ice sheet of the refrigeration load facility 20. Other arrangements are considered as well, depending on the contemplated use of the thermal hub 10.

For example, the evaporation stage 14 may be used to provide cooling to the occupant building 30. In some instances, the refrigeration load facility 20 may have reduced refrigeration requirements as a function of the season. The refrigeration load facility 20 may for instance be an ice rink that is not operated in some summer periods, or may be an outdoor rink that requires limited refrigeration in the winter cold. As a result, the refrigeration load facility 20 may not have to satisfy a cooling demand in such periods. Thus, the evaporation stage 14 may be used to satisfy HVAC cooling demands of the occupant building 30, i.e., in summer periods when outdoor temperatures and sun exposure peak. The evaporation stage 14 may also be in heat exchange with the heat sink 40, such as to store cold.

To complete the refrigeration cycle, the vapor resulting from the evaporation stage 14 is again a saturated vapor and is cycled into the compression stage 11. Depending on the application, a desuperheater may be present to ensure that gas is fed to the compression stage 11. The circuit portion of the thermal hub 10 between the compression stage 11 and the expansion stage 13 (including the condensing stage 12 and receiver(s) 13) may be referred to as the high-pressure side as the refrigerant pressure is higher in comparison to a circuit portion of the thermal hub 10 between the expansion stage 13 and the compression stage 11 (including the evaporation stage 14), itself referred to as the low-pressure side. The demarcation between high-pressure side and low-pressure side may be elsewhere, such as at pressure regulating valve for transcritical refrigeration.

The thermal hub 10 is schematically shown in FIG. 2 as a simplified example of a system capable of operating a refrigeration cycle. However, multiple other features and components may be added to the thermal hub 10, such as desuperheater upstream or as part of condensing/rejection stage 12, defrosting, heat reclaiming, receivers, oil systems, to name but a few, as well as the appropriate piping and valves to ensure that the refrigerant is directed to the various components as desired. Again, the refrigeration system 10 may include a plurality of compressors (e.g., in parallel, cascaded, dedicated), condensers, evaporators, depending on the refrigeration load that must be satisfied by the plant 10. Moreover, different types of refrigerant may be used, including synthetic fluorocarbon refrigerants and their blends (e.g., HCFC, HFC, HFO and blends thereof), ammonia, CO₂refrigerant, hydrocarbon refrigerant, etc, for different uses, such as industrial refrigeration (e.g., process refrigeration, industrial cold storage), ice-playing surfaces (a.k.a., ice sheets), supermarket refrigeration, HVAC, among possibilities.

The compressors of the stages 11 may be in a common stack, skid, rack, for instance in a same mechanical room, with a pipe network corresponding to that shown in the present figures, in terms of connection arrangement (and not in terms of length), along with some components of the condensing stage 12, of the expansion stage 13 and/or of the evaporation stage 14. The common stack may include various valves, etc, as well as a controller unit 15, receivers, etc. This equipment may be in its own building, or may be part of the refrigeration load facility 20 and/or the occupant building 30. Coolant circuits may then be used to convey hot or cold to the refrigeration load facility 20 and/or the occupant building 30, depending on the location of the core components of the thermal hub 10. Although not shown in full detail, the thermal hub 10 may be used with a vast network or circuit of coolant piping, to transmit heat/cold between the thermal hub 10, the refrigeration load facility 20, the occupant building(s) 30 and/or the heat sink 40. The piping may have heat exchangers, receivers, insulated piping, pumps, boosters, etc, to manage the coolant.

The controller unit 15 may be used to centrally control the various components and stages of the thermal hub 10. The controller unit 15 is the processing unit of the thermal hub 10, and may have one or more processors 15A. A non-transitory computer-readable memory 15B may be communicatively coupled to the processing unit and may have computer-readable program instructions executable by the processing unit for operating a transfer cycle described herein. The controller unit 15 may have satellite controller units it communicates with, or other controller units 15 it communicates with. All of the controller units may be referred to as the single controller unit 15 described herein.

The controller unit 15 has a processor with user interfaces, and may receive data from various sensors located at different locations in the thermal hub 10 and in the environment of the thermal hub 10, e.g., temperature and pressure sensors, etc. This may include sensors of all sorts in the refrigeration load facility 20, in the occupant building(s) 30. The controller unit 15 may also communicate with the components of the thermal hub 10, to turn them on and off, and to adjust their operating parameters. This may include the operation of valves (e.g., solenoid valves) located throughout the thermal hub 10. The controller unit 15 may also be in communication with user applications that can seek operator guidance remotely. For example, a user device may be in wireless communication with the controller unit 15, for instance by cellular network and/or internet, etc. Although not shown, the controller unit 15 receives operational data from various sensors in the thermal hub 10, or associated with the thermal hub 10, such as indoor and outdoor temperature sensors (e.g., thermometers, thermocouples).

The controller unit 15 is configured to operate the thermal hub 10 in a standard mode of operation of the main refrigeration circuit. The standard mode of operation has the sequence of the compression stage 11, the condensing/reclaim stage 12, the expansion stage 13 and the evaporation stage 14, as explained above. For simplicity, the operation of the thermal hub 10 as controlled by the controller unit 15 is explained with respect to the use of such a refrigeration system to refrigerate one or more ice sheets in an arena or like skating facility. However, similar principles of operation may be applied to other types of facilities, such as industrial refrigeration systems, supermarkets, etc.

The controller unit 15 is key to the use of the thermal hub 10 in a globally efficient manner. The controller unit 15 may oversee all thermal loads and determine the best strategy, first coupling heating and cooling, then temporarily storing energy, finally drawing or rejecting to/from external sources like the air, ground, sewer.

During operation of the main refrigeration circuit 10A, refrigerant or coolant is fed to the evaporation stage 14 so as to capture heat of the ice sheet. Stated differently, the main refrigeration circuit 10A is operated to meet the cooling load, the cooling load being the amount of energy required to keep the ice sheet(s) at a desired condition. The cooling load may be one or more cooling loads, that may have different requirements, including different refrigeration temperatures, such as for the cooling of freezers and of refrigerators.

Heat reclaim may occur in the condensing/reclaim stage 12. However, in some given operation conditions, such as in winter time, the cooling load may be smaller than in summer operation, for different reasons.

Referring to FIGS. 3-6, via the reclaim capacity of its condensing stage 12, the thermal hub 10 may be configured to generate high-grade heat 12A, namely heat that is at a temperature of 120 or more degrees Fahrenheit (though the lower temperature threshold of high-grade heat could be different). The thermal hub 10 may also generate medium-grade heat 12B, i.e., at a temperature ranging from 80 to 120 degrees Fahrenheit (though the temperature range of medium-grade heat could be different). In some instances, the amount of heat that can be reclaimed is sufficient to supply heat to both heat demands, such as by supplying high-grade heat 12A to a first heat demand (e.g., water heaters), and simultaneously or concurrently supplying medium-grade heat 12B to a second heat demand (e.g., district heating). The thermal hub 10 may hence contribute to substantially meeting or contributing to meeting a given heating load or given heating loads of the occupant building(s) 30, regardless of the cooling load. The controller unit 15 is therefore configured to monitor the operation of the thermal hub 10 and that of a heating load demand(s), and trigger a high-grade heat reclaim mode, and/or a medium-grade heat reclaim mode from the main refrigeration circuit of the thermal hub 10.

Still referring to FIGS. 3-6, via the cooling capacity of the evaporation stage 14, the thermal hub 10 may be configured to generate refrigeration heat 14A, namely heat that is at a typical temperature of 32 or less degrees Fahrenheit (though the temperature of refrigeration heat could be different, such as below 45 degrees Fahrenheit). The thermal hub 10 may also generate comfort cooling heat 14B, i.e., at a temperature ranging from 40 to 70 degrees Fahrenheit (though the temperature range of comfort cooling heat could be different, such as above 45 degrees Fahrenheit). This may once more occur concurrently. The thermal hub 10 may hence contribute to substantially meeting a given cooling load, for refrigeration and possibly for air conditioning, and/or for cooling domestic water. The controller unit 15 is therefore configured to monitor the operation of the thermal hub 10 and that of a cooling load demand or demands, and supply the required cooling heat.

As a first example of an operation mode, FIG. 3 illustrates a scenario in which the refrigeration load facility 20 requires refrigeration 14A for one or more ice sheets. In parallel, the occupant building(s) 30 require high-grade heat 12A, such as to heat water for hot water consumption (e.g., hot water tank) or for space heating, and medium-grade heat 12B (e.g., district heating), and these heat demands may be concurrent. If the occupant building(s) 30 is an industrial facility, high-grade heat 12A may be required for process heating. The scenario of FIG. 3 may be for example in colder months of the year. The heat 12A and 12B may be reclaimed from the condensing stage 12, during a same time period if required. If additional cold heat is required, it may be obtained from the heat sink 40, having previously been stored thereat when cooling demand was low. For example, the heat sink 40 is an ice battery that has stored cold. Alternatively, the heat sink 40 may contribute to providing warm heat to the refrigeration load facility 20 and/or to the occupant building 30, if the heat sink 40 has stored hot heat instead. Thus, the refrigeration load facility 20 and/or the occupant building(s) 30 may also get some high-grade heat 12A and medium-grade heat 12B (e.g., district heating) in such scenario. Other examples of demands for medium-grade heat 12B may include in-floor radiant heating, hot water pre-heat, pool water heating, arena and gym heating, building makeup air preheat, as examples among others. Examples of comfort cooling 14B may include industrial process cooling. Other examples of refrigeration demand 14A include industrial refrigeration warehouses and process areas (e.g., dairy plant, meat plant), as well as other process air cooling, fluid, and product cooling.

As a second example of an operation mode, FIG. 4 illustrates a scenario in which the refrigeration load facility 20 does not need or has limited demand for the refrigeration 14A for one or more ice sheets. In parallel, the occupant building(s) 30 require high-grade heat 12A, such as to heat water for hot water consumption (e.g., hot water tank) and medium-grade heat 12B (e.g., district heating). The refrigeration load facility 20 may also demand some high-grade heat 12A and medium-grade heat 12B (e.g., district heating) in such scenario, such as to satisfy domestic water consumption. The scenario of FIG. 4 may be for example in an intermittent situation, occurring at night in a colder month (e.g. winter months), when an ice sheet is being used and occupants are at home in the building(s) 30. Again, the heat 12A and 12B may be reclaimed from the condensing stage 12, and this heat supply may be concurrent. To offset the generation of heat, cold may be stored in the heat sink 40. For example, the heat sink 40 is an ice battery that generates ice, or may be a geothermal well that stores the cold.

For example, if the outdoor temperature is colder, the cooling load may be smaller due to the fact that less heat is lost to ambient. For example, for the mode of operation of FIG. 4, in the case of a skating facility, the demand for hot water may be large, notably because of restrooms that require hot water, such as for showers. The reclaim contribution of the condensing/reclaim stage 12 may be insufficient to raise the water temperature sufficiently for restrooms/showers. Other sources of heat would usually be used in order to heat up water and provide heat to the occupant building, including natural gas or other combustible fuels, but the heat sink 40 may be used to increase the demand for cooling and reduce the requirements for combustible fuels, and reduce the carbon footprint associated with the heating/cooling of the refrigeration load facility (ies) 20 and occupant building(s) 30.

As a third example of an operation mode, FIG. 5 illustrates a situation in which the refrigeration load facility 20 has no cooling or refrigeration demand. The evaporation stage 14 is therefore used to generate comfort cooling 14B, such as for air conditioning of the occupant building(s) 30, to offset a demand for high-grade heat 12A of the occupant building(s) 30, e.g., hot water demand. Hot water demand is a year-round occurrence. It may be possible to store cold in the heat sink 40 if the heat demand surpasses the cold demand in such a scenario. The scenario of FIG. 5 may be more commonly operated in the summer months. It may also be possible to turn the main refrigeration circuit off, and use the heat sink 40 to provide comfort cooling.

As a fourth example of an operation mode, FIG. 6 depicts a situation in which there is no demand for heat, while refrigeration 14A is required, such as for the ice sheet(s) of the refrigeration load facility 20. The situation of FIG. 6 may occur during daytime work hours in a building tower 30, when the building is mostly empty of its occupant, and there is no hot water demand. For example, this may be an occurrence for milder or warmer outdoor temperatures. Reclaimed heat may be stored in the heat sink 40 for subsequent use, such as when hot water demand will be required when occupants return to the building(s) 30.

While FIGS. 3 to 6 show demands for high-grade heat 12A and medium-grade heat 12B (e.g., concurrent demands), the thermal hub 10 could also supply heat to meet low-grade heat demands, as shown in FIG. 1B, typically at a temperature <80 degrees Fahrenheit. In rinks, low-grade heat demands could include space heating and under-ice frost protection heating in rinks. In industrial facilities, low-grade heat demands could include factory, dry storage, and/or dock space heating, and under cold room frost protection heating and processing heating.

The modes of operation are example among others to illustrate the driving of the thermal hub 10 to minimize heat losses, and to balance heat demand with cooling demand. Such modes of operation may reduce the carbon footprint of the thermal hub 10, depending on the source of electricity, the types of energy used to meet the heating load, and/or the efficiency of equipments, among other factors. Two or more of the modes of operation may be intermittently performed by the controller unit 15, on any given day, with some of the modes being more prevalent than others based on the outdoor temperatures, time of day, occupancy, for example.

The thermal hub 10 is operated by the controller unit 10 to act as energy exchanger matching heating and cooling requirements of the application (refrigeration load facility 20) and the district heating and cooling requirements from the occupant building(s) 30, and vice-versa. The thermal sink or source 40 may be part of the thermal hub 10 in order to balance the needs of the refrigeration load with district heating and cooling requirements.

Accordingly, there may be numerous advantages resulting from the use of the thermal hub 10. For example, natural gas or like fossil fuel consumption may be reduced or, in some instances, may be eliminated. The global energy consumption of the refrigeration load facility 20 and of the occupant building(s) 30 is reduced by the use of the central thermal hub 10, in comparison to the combined energy consumption of independent refrigeration system, heating system, HVAC system for the refrigeration load facility 20 and for the occupant building(s) 30. The equipment costs may be reduced, as a single system may be used, i.e., the thermal hub 10, instead of air-conditioning units in all occupant building(s) 30. If operated by a municipality, or by a building coop, a corporation, it reduces such assets. The controller unit 15 may thus be operated with a goal to save energy. Moreover, the controller unit 15 may take advantage of excess thermal energy and reallocate same appropriately at a reduced cost. For example, the controller unit 15 may take into consideration peak-hour electricity rates by running the various systems on stored heat (including cold heat) when the electricity rate is lower.

In a variant, the thermal hub 10 may generally be described as being for operating a refrigeration system, including a processing unit and a non-transitory computer-readable memory communicatively coupled to the processing unit and comprising computer-readable program instructions executable by the processing unit for operating a main refrigeration circuit as a function of a cooling load of an evaporation stage of a first facility; reclaiming heat from the main refrigeration circuit to provide heat to at least a second facility separate from the first facility in response to at least two concurrent heat demands for at least the second facility; and storing cold heat or hot heat as a function of a difference between the heat reclaimed and the cooling load.

The thermal hub may be said to have a main refrigeration circuit including at least a compression stage, a condensing stage, and an evaporation stage, a refrigerant circulating between the compression stage, the condensing stage and the evaporation stage in a refrigeration cycle. One or more refrigeration load facility is in heat exchange relation with the main refrigeration circuit to receive heat at a temperature of less than 32 Fahrenheit from the evaporation stage. One or more occupant building may be in heat exchange with the main refrigeration circuit to receive heat a temperature greater than 80 Fahrenheit from the condensing stage. One or more heat sinks is in heat exchange with the main refrigeration circuit to receive, store and release cold heat or hot heat. A controller unit is configured for operating the main refrigeration circuit and the at least one heat sink to satisfy heat or cold demand of the at least one refrigeration load facility, of the at least one occupant building.

The thermal hub in another variant may be said to have a main refrigeration circuit including at least a compression stage, a condensing stage, and an evaporation stage, a refrigerant circulating between the compression stage, the condensing stage and the evaporation stage in a refrigeration cycle; at least one refrigeration load facility in heat exchange relation with the main refrigeration circuit to receive cold from the evaporation stage in a response to a cooling load demand; at least one occupant building in heat exchange with the main refrigeration circuit to receive heat from the condensing stage in response to at least two concurrent heat demands, the heat demands different from one another; at least one heat sink in heat exchange with the main refrigeration circuit to receive, store and release cold heat or hot heat; and a controller unit configured for operating the main refrigeration circuit and the at least one heat sink to satisfy heat or cold demand of the at least one refrigeration load facility, of the at least one occupant building.

The controller unit 15 may have as a primary priority the coupling of thermal loads in the thermal hub 10. As a secondary priority, the controller unit 15 may temporarily store or remove thermal energy, in the heat sink 40 (or any equivalent). The controller unit 15 may permanently absorb or reject thermal energy, to the heat sink 40, to the environment, if the priorities cannot be satisfied, or if they have been satisfied to some extent. The controller unit 15 may take into consideration factors as current energy price, time of day, anticipated consumption, anticipated building occupancy, weather forecast, etc. The controller unit 15 may optimize the operation of the various components of the thermal hub 10 to have the lowest energy consumption as possible and/or the lowest carbon emissions. Evaporators, compressors, condensers in the thermal hub 10 can be temporarily coupled as required, with the components of the thermal hub 10 being highly modular by way of appropriate valves and networks, for the controller unit 15 to be capable of satisfying its priorities when possible. For example, the compressors 11, the condenser 12, the evaporators 14 may not be hard coupled, to enable a shuffling of components, a creation of numerous parallel Carnot cycles, etc.

THERMAL HUB SYSTEM FEATURING REFRIGERATION

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