Patent Application
20250237414
This disclosure relates generally to heating, ventilation, and air conditioning systems including heat pump systems, chillers, and heat recovery systems.
Often, commercial or institutional buildings have a year-round cooling demand as well as a heating demand in the winter. To meet the cooling demand, air cooled chillers may be used in commercial buildings for process cooling and for space conditioning to cool and dehumidify the air in the building. To meet the heating demand, natural gas may be used to heat domestic water and for space heating in the building. However, as environmental concerns continue to increase against the use of natural gas for space heating purposes, there exists a need to develop alternative means for heating water and for space heating in a building. Air cooled chillers configured to act as heat pumps capable of reversing direction of the refrigerant can be assembled together as a chiller bank to provide heating and cooling simultaneously to the building. The challenge with this approach is that existing solutions are limited on how much output is available in either the cooling mode or the heating mode. As demand for heating exceeds the capacity of such systems to deliver heat, and particularly at the peak heating demand, while delivering enough cooling to meet the cooling demand, the size of the chiller bank must grow. But expanding the number of units in the chiller bank to meet these demands results in a system that is more expensive and requires a larger footprint to house the system.
Thus, there exists a need to solve these and other problems to efficiently meet heating and cooling loads.
Disclosed herein are various embodiments of a chiller system to meet the heating and/or cooling loads of or associated with a building or industrial process. In one embodiment, a chiller system includes (i) a refrigerant circuit through which a refrigerant is configured to flow; (ii) a compressor disposed on the refrigerant circuit, the compressor including a compressor inlet, a compressor outlet, and a vapor injection inlet disposed between the compressor inlet and the compressor outlet; (iii) a first load heat exchanger disposed on the refrigerant circuit to exchange heat between the refrigerant and a first load, the first load heat exchanger having an active state and an inactive state and operable as a condenser or an evaporator; (iv) a second load heat exchanger disposed on the refrigerant circuit to exchange heat between the refrigerant and a second load, the second load heat exchanger having an active state and an inactive state and operable as the evaporator; (v) a second load heat exchanger disposed on the refrigerant circuit to exchange heat between the refrigerant and a second load, the second load heat exchanger having an active state and an inactive state and operable as the evaporator; (vi) a source heat exchanger disposed on the refrigerant circuit to exchange heat between the refrigerant and a source, the source heat exchanger the first load heat exchanger having an active state and an inactive state and operable as the condenser or the evaporator; (vii) a reversing valve disposed on the refrigerant circuit and including a first port connected to a pressure side of the compressor, a second port connected to the first load heat exchanger, a third port connected to the source heat exchanger, and a fourth port connected to a suction side of the compressor; (viii) a receiver positioned downstream of the first load heat exchanger and configured to act as a reservoir for the refrigerant; and (ix) an expansion valve positioned (a) between the receiver and the source heat exchanger when the chiller system is configured to operate in a first operating mode, (b) between the source heat exchanger and the second load heat exchanger when the chiller system is configured to operate in a second operating mode, (c) between the source heat exchanger and the first load heat exchanger when the chiller system is configured to operate in a third operating mode, and (d) between the receiver and the second load heat exchanger when the chiller system is configured to operate in a fourth operating mode.
The compressor may be a variable speed compressor. The chiller system may include an intermediate evaporator and an intermediate evaporator expansion valve disposed on a vapor injection circuit that is connected to the refrigerant circuit, where (i) a first portion of the refrigerant may be diverted from the refrigerant circuit downstream of the first load heat exchanger to the intermediate evaporator expansion valve, and (ii) the diverted first portion of the refrigerant leaving the intermediate evaporator expansion valve may be directed to the intermediate evaporator to exchange heat with a second portion of the refrigerant in the refrigerant circuit to vaporize the diverted first portion of the refrigerant for entry into the vapor injection inlet of the compressor. The intermediate evaporator expansion valve may control an amount of the first portion of the refrigerant that is diverted from the refrigerant circuit to the vapor injection circuit. The amount of the first portion may range from 10% to 25%.
The reversing valve may be configured to route the refrigerant to the compressor, the first load heat exchanger, and the source heat exchanger and to receive the refrigerant from the compressor, the source heat exchanger, and the first load heat exchanger.
The chiller system may include a first check valve positioned between the receiver and the expansion valve. The first check valve may allow the refrigerant to flow from the receiver to the expansion valve and may inhibit flow of the refrigerant from the expansion valve to the receiver. The chiller system may include a second check valve disposed between the expansion valve and the source heat exchanger. The second check valve may allow the refrigerant to flow from the expansion valve to the source heat exchanger and may inhibit flow of the refrigerant from the source heat exchanger to the expansion valve. The chiller system may include a third check valve disposed on a branch circuit connected to the refrigerant circuit. The third check valve may be disposed between the expansion valve and the source heat exchanger. The third check valve may allow the refrigerant to flow from the source heat exchanger to the expansion valve and may inhibit flow of the refrigerant from the expansion valve to the source heat exchanger. The chiller system may include a fourth check valve disposed on a defrost circuit connected to the refrigerant circuit. The fourth check valve may be disposed between the expansion valve and the first load heat exchanger. The fourth check valve may allow the refrigerant to flow from the expansion valve to the first load heat exchanger and may inhibit flow of the refrigerant from the first load heat exchanger to the expansion valve
The chiller system may include a first solenoid valve disposed on a bypass circuit that is connected to the refrigerant circuit where (i) the bypass circuit may be positioned between the compressor and the expansion valve, and (ii) when the first solenoid valve is open, a first portion of the refrigerant leaving the compressor may be diverted to the first solenoid valve and then merged with a second portion of the refrigerant in the refrigerant circuit at a location downstream of the expansion valve and upstream of the source heat exchanger. The chiller system may include a second solenoid valve disposed on a defrost circuit that is connected to the refrigerant circuit. The defrost circuit may be positioned between the expansion valve and the first load heat exchanger.
The chiller system may include a controller comprising a processor and memory and configured to control operation of the compressor, the reversing valve, the expansion valve, the first load heat exchanger, the second load heat exchanger, and the source heat exchanger.
The first operating mode of the chiller system may be a heating mode, and in the heating mode the controller may be configured to: (i) control the reversing valve to receive the refrigerant from the compressor and direct the refrigerant to the first load heat exchanger acting as the condenser; (ii) close the first solenoid valve to inhibit flow of the refrigerant to the bypass circuit; (iii) close the second solenoid valve to inhibit flow of the refrigerant to the defrost circuit; (iv) close a third solenoid valve to inactivate the second load heat exchanger; (v) open a fourth solenoid valve to direct the refrigerant from the expansion valve to the source heat exchanger acting as the evaporator; and (vi) control the reversing valve to receive the refrigerant leaving the source heat exchanger and direct the refrigerant to the compressor.
The chiller system may include a heating and frost mitigation mode, and in the heating and frost mitigation mode, the controller may be configured to: (i) control the reversing valve to receive the refrigerant from the compressor and direct the refrigerant to the first load heat exchanger acting as the condenser; (ii) open the first solenoid valve to divert the first portion of the refrigerant leaving the compressor to the first solenoid valve along the bypass circuit, wherein the first portion of the refrigerant is merged with the second portion of the refrigerant and merged with the second portion of the refrigerant in the refrigerant circuit at the location downstream of the expansion valve and upstream of the source heat exchanger; (iii) close the second solenoid valve to inhibit flow of the refrigerant to the defrost circuit; (iv) close a third solenoid valve to inactivate the second load heat exchanger; (v) open a fourth solenoid valve to direct the refrigerant from the expansion valve to the source heat exchanger acting as the evaporator; and (vii) control the reversing valve to receive the refrigerant leaving the source heat exchanger and direct the refrigerant to the compressor.
The second operating mode of the chiller system may be a cooling mode, and in the cooling mode the controller may be configured to: (i) control the reversing valve to receive the refrigerant from the compressor and direct the refrigerant to the source heat exchanger acting as the condenser; (ii) close the first solenoid valve to inhibit flow of the refrigerant to the bypass circuit; (iii) close the second solenoid valve to inhibit flow of the refrigerant to the defrost circuit; and (iv) open a third solenoid valve and close a fourth solenoid valve to direct the refrigerant from the expansion valve to the second load heat exchanger acting as the evaporator, where the refrigerant leaving the second load heat exchanger is returned to the compressor.
The third operating mode of the chiller system may be a cooling and defrost mode, and in the cooling and defrost mode the controller may be configured to: (i) control the reversing valve to receive the refrigerant from the compressor and direct the refrigerant to the source heat exchanger acting as the condenser; (ii) close the first solenoid valve to inhibit flow of the refrigerant to the bypass circuit; (iii) open the second solenoid valve to direct the refrigerant to the defrost circuit; and (iv) close a third solenoid valve and close a fourth solenoid valve to direct the refrigerant from the expansion valve to the second solenoid valve, and from the second solenoid valve to the first load heat exchanger acting as the evaporator, where the refrigerant leaving the first load heat exchanger is direct to the reversing valve, which directs the refrigerant to the compressor.
The fourth operating mode of the chiller may be a simultaneous heating and cooling mode, and in the simultaneous heating and cooling mode the controller may be configured to: (i) control the reversing valve to receive the refrigerant from the compressor and direct the refrigerant to the first load heat exchanger acting as the condenser; (ii) close the first solenoid valve to inhibit flow of the refrigerant to the bypass circuit; (iii) close the second solenoid valve to inhibit flow of the refrigerant to the defrost circuit; and (iv) open a third solenoid valve and close a fourth solenoid valve to direct the refrigerant from the expansion valve to the second load heat exchanger acting as the evaporator, thereby inactivating the source heat exchanger, where the refrigerant leaving the second load heat exchanger is returned to the compressor.
In another embodiment, a chiller system includes (i) a refrigerant circuit through which a refrigerant is configured to flow; (ii) a defrost circuit connected to the refrigerant circuit through which the refrigerant is configured to flow when the chiller system is in a defrost operating mode; (iii) a source heat exchanger frost mitigation circuit connected to the refrigerant circuit through which a first portion of the refrigerant is configured to flow when the chiller system is in a source heat exchanger frost mitigation operating mode; (iv) a vapor injection circuit connected to the refrigerant circuit through which a second portion of the refrigerant is configured to flow, the vapor injection circuit configured to vaporize the second portion of the refrigerant and direct the vaporized second portion of the refrigerant circuit to the a vapor injection inlet of the compressor; (v) a variable speed compressor disposed on the refrigerant circuit, the compressor including a compressor inlet, a compressor outlet, and a vapor injection inlet disposed between the compressor inlet and the compressor outlet; (vi) a refrigerant-to-water first load heat exchanger disposed on the refrigerant circuit to exchange heat between the refrigerant and a first load, the first load heat exchanger having an active state and an inactive state and operable as a condenser or an evaporator; (vii) a refrigerant-to-water second load heat exchanger disposed on the refrigerant circuit to exchange heat between the refrigerant and a second load, the second load heat exchanger having an active state and an inactive state and operable as the evaporator; (viii) a refrigerant-to-air source heat exchanger disposed on the refrigerant circuit to exchange heat between the refrigerant and a source, the source heat exchanger the first load heat exchanger having an active state and an inactive state and operable as the condenser or the evaporator; (ix) a reversing valve disposed on the refrigerant circuit and including a first port connected to a pressure side of the compressor, a second port connected to the first load heat exchanger, a third port connected to the source heat exchanger, and a fourth port connected to a suction side of the compressor; and (x) an expansion valve positioned (a) between the first load heat exchanger and the source heat exchanger when the chiller system is configured to operate in a first operating mode, (b) between the source heat exchanger and the second load heat exchanger when the chiller system is configured to operate in a second operating mode, (c) between the source heat exchanger and the first load heat exchanger when the chiller system is configured to operate in a third operating mode, and (d) between the first load heat exchanger and the second load heat exchanger when the chiller system is configured to operate in a fourth operating mode, where a direction of flow of the refrigerant through the expansion valve for the first operating mode is identical to the direction of flow of the refrigerant through the expansion valve for the second operating mode, the third operating mode and the fourth operating mode.
The chiller system may include a controller comprising a processor and memory and configured to control operation of the compressor, the reversing valve, the expansion valve, the first load heat exchanger, the second load heat exchanger, and the source heat exchanger.
Although the figures and the instant disclosure describe one or more embodiments of a chiller system, one of ordinary skill in the art would appreciate that the teachings of the instant disclosure would not be limited to these embodiments. It should be appreciated that any of the features of an embodiment discussed with reference to the figures herein may be combined with or substituted for features discussed in connection with other embodiments in this disclosure.
Various embodiments of modular chiller systems are disclosed herein. Modular chiller systems of the instant disclosure offer a number of advantages over known solutions, including providing more heating and cooling capacity than known solutions. In various embodiments, three heat exchangers are arranged to allow one of the heat exchangers to be inactive when not needed. Modular chiller systems of the instant disclosure can be configured to operate in either a dedicated cooling mode, a dedicated heating mode, or a simultaneous heat recovery mode. In a simultaneous operating mode, the design of the refrigerant circuit enables simultaneous delivery of heated and chilled water that efficiently meets peak heating demand while also meeting the cooling demand.
In various embodiments, modular chiller systems of the instant disclosure can simultaneously control two different loads with a single unit. For example, one heat exchanger may be configured to provide chilled water to a building, another heat exchanger may be configured to provide heated water to the building, or simultaneously operate to provide both chilled and heated water to the building. In simultaneous mode, one of three heat exchangers may be configured to be inactive insofar as no heat is exchanged by the heat exchanger either because (i) an associated blower or fan is turned off if, for example, the heat exchanger is configured as a refrigerant-to-air heat exchanger, (ii) a pump is turned off if, for example, the heat exchanger is configured as a refrigerant-to-liquid heat exchanger, or (iii) refrigerant is prevented from circulating through the heat exchanger by closing one or more valves upstream and/or downstream of the heat exchanger.
In various embodiments, modular chiller systems of the instant disclosure may be arranged to combine multiple modular chiller systems together in a bank. A modular chiller bank with each modular chiller system operating in simultaneous heat recovery mode produces a much larger total capacity bank and can produce equivalent or larger output than the peak cooling or heating demand. In simultaneous mode, the conditions are more favorable, thus allowing the unit to improve overall output.
In various embodiments, modular chiller systems of the instant disclosure may be configured to operate at least one of the load heat exchangers as either a condenser or an evaporator. When operating as an evaporator, one of the load heat exchangers may actively defrost the source heat exchanger to thaw or prevent icing therein. To do so, the reversing valve may shift from a heating mode to a defrost mode where heat is removed from the heated space.
In various embodiments, modular chiller systems of the instant disclosure may be configured to operate in a heating mode that mitigates the development of frost in the source heat exchanger configured to operate as an evaporator—without having to reverse the direction of the refrigerant. During frost mitigation, hot gas from the compressor that bypasses the load heat exchanger may be directed upstream of the source heat exchanger and metered to modulate the temperature of the refrigerant circulating through the source heat exchanger. This approach avoids the need for reversing the direction of the refrigerant at low ambient temperatures to take heat out of the load or space being conditioned and using that heat to mitigate freezing in the source heat exchanger. In addition, it is more favorable to reduce heat output from the load heat exchanger than to reverse the direction of the refrigerant, which would cease heat output from the load heat exchanger altogether.
In various embodiments, modular chiller systems of the instant disclosure may include a variable speed compressor to vary the compressor output to best match the heating and cooling loads.
In various embodiments, modular chiller systems of the instant disclosure may include a vapor injection or subcooler circuit to assist meeting heating demand in the heating mode and in simultaneous heating and cooling mode.
In various embodiments, modular chiller systems of the instant disclosure may combine the vapor injection circuit and the refrigeration circuit that enables simultaneous heating and cooling in a single housing or enclosure. Moreover, by combining multiple, independent refrigerant circuits for multiple units in a single housing or enclosure, the system may enable operating in multiple simultaneous modes. For example, compressor-1/refrigerant circuit-1 may operate in simultaneous heating and cooling mode while compressor-2/refrigerant circuit-2 may operate in a dedicated heating or cooling mode instead of both compressors operating in the simultaneous heating and cooling mode, where compressor-1/refrigerant circuit-1 and compressor-2/refrigerant circuit-2 are both housed in the same housing or enclosure. This approach addresses the situation where, rather than arranging two units in a bank, a single unit system is provided to meet the anticipated heating and cooling demands.
In various embodiments, each of the modular chiller systems of the instant disclosure may include a controller that is configured to operate that modular chiller system as well as all of other modular chiller systems if installed in a bank of modular chiller systems. Alternatively, a master controller, such as a building controller, may be configured to communicate with each of the unit controllers to operate each of the modular chiller systems in the bank.
In various embodiments, modular chiller systems of the instant disclosure may be configured as a split system where the fan motor assembly and source heat exchanger may be housed in an enclosure outside the building while the compressor, load heat exchangers, and the remainder of the refrigerant circuit is housed in an enclosure inside the building. A split system of this type eliminates the need for any antifreeze or brine solutions in the water circuits associated with the load heat exchangers (if configured as refrigerant-to-liquid heat exchangers) that may be needed to prevent them from freezing if the entire modular chiller system were housed outdoors. Utilizing water for the load liquid circuits would be more efficient, less harmful to the environment, and would enhance overall servicing and reliability of the system. In addition, positioning the compressor section inside the building would tend to enhance overall reliability of the compressor.
In various embodiments, modular chiller systems of the instant disclosure may be used to revitalize and/or upgrade existing geothermal loop fields that are undersized for the heating and cooling loads of a building, such as when the building has been expanded thereby increasing the heating and cooling loads that are placed upon the incumbent heating and cooling system.
In various embodiments, modular chiller systems of the instant disclosure may be configured to address the total heating and cooling demands at extreme outdoor temperatures (i.e., from −25° F. to 120° F.) to either replace or obviate the need, for example, for requiring an auxiliary boiler, duct heater, or other auxiliary heating system to satisfy the heating demand when outdoor temperatures are less than 5° F. to −25° F. To do that, different operating modes of the modular chiller systems of the instant disclosure may create capacity by utilizing refrigerant housed in various unused portions of the refrigerant circuit that are exposed to suction from the compressor. Through computer controlled opening and closing of various on/off solenoid valves in the refrigerant circuit together with various flow control devices such as one-way check valves, the modular chiller systems of the instant disclosure may operate in one or more operating modes (sometimes simultaneously) while also satisfying a building's heating and cooling demands at unusually high and low outside temperatures. In various embodiments, modular chiller systems of the instant disclosure may be configured with a vapor injection refrigeration circuit to provide up to a 25% boost in heating capacity on days when outside temperatures fall below 17° F., for example, and to enable modular chiller systems of the instant disclosure to operate efficiently when outside temperatures are as low as −25° F.
Turning now to the drawings and to
Heat exchangers 4, 18, and 26 may be configured as either refrigerant-to-air or refrigerant-to-liquid heat exchangers. If configured as refrigerant-to-air, then one or more of fans 33, 34, and 35 may be utilized to exchange heat between the refrigerant and air. If refrigerant-to-liquid, then the modular chiller systems of the instant disclosure may include one or more valves 29,31,49 and/or one or more associated liquid pumps for circulating liquid to and from loads 30,32 and/or source 37 via load loops 43,44 and source loop 42 to enable exchange of heat between the refrigerant and the liquid.
It should be appreciated that hot gas valve 25 may be a proportional solenoid valve to modulate refrigerant flow, and that any or all of the liquid pumps may be variable flow liquid pumps. In addition, to enable modular chiller systems of the instant disclosure to shift on the fly from one operating mode to another operating mode without having to shut down and restart between different operating modes, one or more of valves 13, 17, and 20 may be configured as solenoid valves. Alternatively, one or more of valves 13, 17, and 20 may be configured as ball valves, for example, but the opening and closing times of such valves may be relatively long and may require system shut down and restart when shifting from one operating mode to another operating mode.
If valves 13 and 20 are configured as solenoid valves, it should be appreciated that such valves may be configured to allow refrigerant flow in one direction and may not be able to handle high pressure flow in the opposite direction when closed. Such valves may leak if high pressure refrigerant exists on the other side of such valves. To prevent high pressure refrigerant on the opposite side of such valves, modular chiller systems of the instant disclosure include one or more of one-way check valves 9 and 21 positioned adjacent to valves 13 and 20 to ensure that high pressure refrigerant does not backflow to such valves. Likewise, to control direction of refrigerant flow, one-way check valve 11 is positioned downstream of receiver 10 to prevent refrigerant backflow to receiver 10, and one-way check valve 22 is positioned downstream of one-way check valve 11 to ensure refrigerant flows to expansion valve 14 in all of the operating modes of the modular chiller systems of the instant disclosure.
Each fan 33, 34, 35 may each comprise one or more fans to obtain a desired total flowrate, fan speed, and quietness. Each load loop 43,44 may additionally include one valve for incoming liquid and one for outgoing liquid to control enable modular chiller systems of the instant disclosure to be independently controlled in a bank of units, as shown and described more fully below with respect to
Modular chiller systems of the instant disclosure may also include controller 36, which may be functionally connected to one or more of the foregoing components (as well as other components not shown) to control the operation, position, or function of one or more features of one or more of these components. For example, controller 36 may control the direction of flow and the flowrate of refrigerant in refrigerant circuit 40 according to an operational mode of the modular chiller systems of the instant disclosure as well as the heating and cooling demand on the modular chiller system of the instant disclosure.
Modular chiller system 100 may additionally include intermediate evaporator 7 and expansion valve 8 disposed along refrigerant circuit 39 to create refrigerant vapor for injection into the compressor 1, as doing so may boost heating capacity of the system to accommodate greater heating demand than without these embellishments. Optional intermediate evaporator 7 may be configured as a refrigerant-to-refrigerant heat exchanger acting as an evaporator to exchange heat between refrigerant circulating through refrigerant circuit 39 and refrigerant circulating through refrigerant circuit 40. As shown in
Hot compressed refrigerant gas leaving compressor 1 is conveyed via conduit 201 and tee fitting 2 to reversing valve 3. The hot compressed refrigerant gas is conveyed via conduit 202 to load heat exchanger 4 configured, for example, as a refrigerant-to-water heat exchanger. Load heat exchanger 4 is configured to exchange heat between the refrigerant and water circulating through open valve 29 to create heated water to satisfy a heating load 30. The hot compressed refrigerant gas enters load heat exchanger 4 acting as a condenser to cause the refrigerant to condense to a liquid. If load heat exchanger 4 is a refrigerant-to-water heat exchanger, such as a coaxial heat exchanger, then the compressed refrigerant gas may exchange heat with relatively cooler water flowing through load loop 43 to created heated water to satisfy the heating load 30. Alternatively, if load heat exchanger 4 is a refrigerant-to-air heat exchanger, air flowing over the tubes/passages carrying refrigerant through load heat exchanger 4 may cool the refrigerant. As the refrigerant gas is condensed into a liquid, heat is concurrently released from the refrigerant and absorbed by the air as it passes over the tubes/passages of load heat exchanger 4, and the heated air may then be utilized to heat, for example, a space within the building or structure.
Liquid refrigerant (at relatively high pressure) exits load heat exchanger 4 and is conveyed via conduit 203 to intermediate evaporator 7, if present. The orientation of check valve 9 along defrost circuit 41 prevents refrigerant flow towards closed valve 13. The orientation of check valve 9 also helps ensure that high pressure refrigerant does not leak through closed valve 13 when lower pressure exists on the other side of valve 13 (i.e., between valve 13 and tee fitting 15 along conduit 210) in this operating mode. Likewise, a portion of the liquid refrigerant is directed by tee fitting 6 to expansion valve 8, if present, via conduit 204 to separate high and low pressure refrigerant and to meter the refrigerant as a liquid for entry to the intermediate evaporator 7. Refrigerant vapor leaving intermediate evaporator 7 is directed via conduit 205 of refrigerant circuit 39 to suction side of compressor 1.
Liquid refrigerant leaving intermediate evaporator 7 via conduit 206 is directed to filter 27, if present, and then to receiver 10 for storing refrigerant charge that is not needed for heating. Liquid refrigerant leaving receiver 10 is directed to expansion valve 14 via conduit 207, check valve 11, and tee fitting 12 to separate high and low pressure refrigerant and to meter the refrigerant as a liquid. Check valve 22 positioned along branch circuit 275 prevents refrigerant flow toward conduit 209. Likewise, valves 13,17 are closed to prevent refrigerant flow through conduits 210,214. Refrigerant leaving expansion valve 14 is conveyed via conduit 211 to and through open valve 20 and through check valve 21. With valve 25 closed and orientation of check valve 22 preventing refrigerant flow toward conduit 219 of branch circuit 275, refrigerant is then directed via conduit 212 to distributor manifold 28, if present, and then to active source heat exchanger 26 acting as an evaporator.
If source exchanger 26 is a refrigerant-to-liquid heat exchanger, such as a coaxial heat exchanger, then the liquid refrigerant may exchange heat with relatively warmer liquid flowing through a source loop 42 (see, e.g.,
With valve 25 closed and expansion valve 8 closed, hot compressed refrigerant gas leaving compressor 1 is conveyed via conduit 201 to reversing valve 3. The hot compressed refrigerant gas leaving reversing valve 3 is conveyed via conduit 213 to source heat exchanger 26 configured, for example, as a refrigerant-to-air heat exchanger acting as a condenser and configured to exchange heat between the refrigerant and air to cause the refrigerant to condense to a liquid. One or more fans 34 are configured to blow air over the tubes/passages carrying refrigerant through source heat exchanger 26 to transport heated air for exhaustion to the ambient air environment outside of the building or directed elsewhere for other useful purposes.
Liquid refrigerant (at relatively high pressure) exits source heat exchanger 26 and is conveyed via conduit 221 to distributor manifold 28, if present. With check valve 21 configured to prevent flow therethrough, liquid refrigerant leaving distributor manifold 28 is directed via conduits 212,219 and tee fitting 24 to check valve 22 positioned along branch circuit 275. The orientation of check valve 21 also helps ensure that high pressure refrigerant does not leak through closed valve 20 when lower pressure exists on the other side of valve 20 (i.e., between valve 20 and tee fitting 16 along conduit 211) in this operating mode. Liquid refrigerant leaving check valve 22 is directed to expansion valve 14 via conduit 209 and via tee fitting 12 because check valve 11 prevents flow of refrigerant toward receiver 10. Liquid refrigerant leaving expansion valve 14 is conveyed via tee fitting 16 and conduit 214 to open valve 17 due to valves 13 and 20 being closed. Refrigerant leaving valve 17 is directed to load heat exchanger 18 via conduit 215. Load heat exchanger 18 may be configured, for example, as a refrigerant-to-water heat exchanger, such as a coaxial heat exchanger, acting as an evaporator.
If load heat exchanger 18 is a refrigerant-to-water heat exchanger, such as a coaxial heat exchanger, then the refrigerant may exchange heat with relatively warmer water flowing through load loop 44 to chill the water for distribution by load loop 44 to satisfy the cooling load 32. Alternatively, if load heat exchanger 18 is a refrigerant-to-air heat exchanger, air flowing over the tubes/passages carrying refrigerant through load heat exchanger 18 may heat the refrigerant. As the refrigerant gas is vaporized, heat is removed from the air as it passes over the tubes/passages of load heat exchanger 18, and the cooled air may then be utilized to satisfy the cooling load 32.
Refrigerant leaving load heat exchanger 18 via conduit 216 is returned to the suction side of compressor 1 via check valve 50 and tee fitting 19. The orientation of check valve 51 positioned along conduit 220 prevents refrigerant from flowing to reversing valve 3. In the air-to-water heating operating mode shown in
With valve 25 closed and expansion valve 8 closed, hot compressed refrigerant gas leaving compressor 1 is conveyed via conduit 201 to reversing valve 3. The hot compressed refrigerant gas leaving reversing valve 3 is conveyed via conduit 213 to source heat exchanger 26 configured, for example, as a refrigerant-to-air heat exchanger acting as a condenser and configured to exchange heat between the refrigerant and air to cause the refrigerant to condense to a liquid. One or more fans 34 are configured to blow air over the tubes/passages carrying refrigerant through source heat exchanger 26 to transport heated air to the ambient air environment outside of the building.
Liquid refrigerant (at relatively high pressure) exits source heat exchanger 26 and is conveyed via conduit 221 to distributor manifold 28, if present. With check valve 21 configured to prevent flow therethrough, liquid refrigerant leaving distributor manifold 28 is directed via conduits 212,219 and tee fitting 23 to check valve 22 positioned along branch circuit 275. The orientation of check valve 21 also helps ensure that high pressure refrigerant does not leak through closed valve 20 when lower pressure exists on the other side of valve 20 (i.e., between valve 20 and tee fitting 15 along conduit 211) in this operating mode. Liquid refrigerant leaving check valve 22 is directed to expansion valve 14 via conduit 209 and via tee fitting 12 because check valve 11 prevents flow of refrigerant toward receiver 10. Refrigerant leaving expansion valve 14 is conveyed via tee fitting 15 and conduit 210 to open valve 13 and through check valve 9 of defrost circuit 41 due to valves 17 and 20 being closed. Refrigerant leaving check valve 9 is directed to load heat exchanger 4 via tee fitting 5 and conduits 208,203. Load heat exchanger 4 may be configured, for example, as a refrigerant-to-water heat exchanger, such as a coaxial heat exchanger, acting as an evaporator.
If load heat exchanger 4 is a refrigerant-to-water heat exchanger, such as a coaxial heat exchanger, then the refrigerant may exchange heat with relatively warmer water flowing through load loop 43 to chill the water for distribution by load loop 43 to satisfy the cooling load 30. Alternatively, if load heat exchanger 4 is a refrigerant-to-air heat exchanger, air flowing over the tubes/passages carrying refrigerant through load heat exchanger 4 may heat the refrigerant. As the refrigerant gas is vaporized, heat is removed from the air as it passes over the tubes/passages of load heat exchanger 4, and the cooled air may then be utilized to satisfy the cooling load 30.
Refrigerant leaving load heat exchanger 4 is conveyed to reversing valve 3 via conduit 202. Refrigerant leaving reversing valve 3 is conveyed via conduit 220, check valve 51, and tee fitting 19 to the suction side of compressor 1. The orientation of check valve 50 positioned along conduit 216 prevents refrigerant from flowing to inactive load heat exchanger 18. In the operating mode shown in
Hot compressed refrigerant gas leaving compressor 1 is conveyed via conduit 201 and tee fitting 2 to reversing valve 3. The hot compressed refrigerant gas is conveyed via conduit 202 to load heat exchanger 4 configured, for example, as a refrigerant-to-water heat exchanger. Load heat exchanger 4 is configured to exchange heat between the refrigerant and water circulating through open valve 29 to create heated water to satisfy a heating load 30. The hot compressed refrigerant gas enters load heat exchanger 4 acting as a condenser to cause the refrigerant to condense to a liquid. If load heat exchanger 4 is a refrigerant-to-water heat exchanger, such as a coaxial heat exchanger, then the compressed refrigerant gas may exchange heat with relatively cooler water flowing through load loop 43 to created heated water to satisfy the heating load 30. Alternatively, if load heat exchanger 4 is a refrigerant-to-air heat exchanger, air flowing over the tubes/passages carrying refrigerant through load heat exchanger 4 may cool the refrigerant. As the refrigerant gas is condensed into a liquid, heat is concurrently released from the refrigerant and absorbed by the air as it passes over the tubes/passages of load heat exchanger 4, and the heated air may then be utilized to heat, for example, a space within the building or structure.
Liquid refrigerant (at relatively high pressure) exits load heat exchanger 4 and is conveyed via conduit 203 to intermediate evaporator 7, if present. The orientation of check valve 9 along defrost circuit 41 prevents refrigerant flow towards closed valve 13. The orientation of check valve 9 also helps ensure that high pressure refrigerant does not leak through closed valve 13 when lower pressure exists on the other side of valve 13 (i.e., between valve 13 and tee fitting 15 along conduit 210) in this operating mode. Likewise, a portion of the liquid refrigerant is directed by tee fitting 6 to expansion valve 8, if present, via conduit 204 to separate high and low pressure refrigerant and to meter the refrigerant as a liquid for entry to the intermediate evaporator 7. Refrigerant vapor leaving intermediate evaporator 7 is directed via conduit 205 of refrigerant circuit 39 to suction side of compressor 1.
Liquid refrigerant leaving intermediate evaporator 7 via conduit 206 is directed to filter 27, if present, and then to receiver 10 for storing refrigerant charge that is not needed for heating. Liquid refrigerant leaving receiver 10 is directed to expansion valve 14 via conduit 207, check valve 11, and tee fitting 12 to separate high and low pressure refrigerant and to meter the refrigerant as a liquid. Check valve 22 prevents refrigerant flow toward conduit 209 of branch circuit 275. Likewise, valves 13,20 are closed to prevent refrigerant flow through conduits 210,211. Refrigerant leaving expansion valve 14 is conveyed via conduit 214 to and through open valve 17. Refrigerant leaving valve 17 is conveyed via conduit 215 to active load heat exchanger 18 acting as an evaporator.
If load exchanger 18 is a refrigerant-to-liquid heat exchanger as shown in
In embodiments in which one or more fans 33,34,35 are included in the modular chiller system, controller 36 may be configured to (wired or wirelessly) communicate with the one or more fans 33,34,35 (including each of the fans in a fan array) to control (1) an on/off state of the fan motor, and (2) the speed of the motor that drives the respective fan. Controlling the speed of the motor, and thus the amount of air passed over the tubes/passages carrying refrigerant through source heat exchanger 26 and/or load heat exchangers 4,18 (if such heat exchangers are configured as refrigerant-to-air heat exchangers) by one or more fans 33,34,35, will control the amount of heat exchange that occurs in these heat exchangers. A variable frequency drive (VFD) may be coupled to each motor that drives the one or more fans 33,34,35. The VFD may be configured to drive the motor at any one of a number of different frequencies, including but not limited to line voltage frequency, to control the speed at which the motor operates to cause the amount of heat exchange in the source heat exchanger 26 and/or load heat exchangers 4,18 to match the demand placed on modular chiller system 100. In other embodiments, the motor is driven by a PWM signal according to a predetermined duty cycle to control the speed of the motor that drives the one or more fans 33,34,35.
Controller 36 may be configured to (wired or wirelessly) communicate with compressor 1 to control (1) the on/off operational state of the compressor 1, and (2) the speed at which compressor 1 operates to compress refrigerant according to the demand placed on modular chiller system 100 and the operational mode of modular chiller system 100. A variable frequency drive (VFD) may be coupled to compressor 1 to drive the compressor at any one of a number of different frequencies, including but not limited to line voltage frequency, to control the speed at which compressor 1 operates to match the demand placed on modular chiller system 100. In other embodiments, the compressor is driven by a PWM signal according to a predetermined duty cycle to control the speed of the compressor 1.
Controller 36 may be configured to (wired or wirelessly) communicate with expansion valves 8,14 to precisely control the size of the orifice through which refrigerant flows in refrigerant circuit 39,40. Controller 36 may send and receive signals to and from a motor connected to expansion valves 8,14 to precisely open and close a refrigerant discharge port of expansion valves 8,14 and to report the position of the motor and/or valve to controller 36.
Controller 36 may be configured to (wired or wirelessly) communicate with variable speed pumps 131,132,133 to control the rate at which the pumps cause water and/or liquid to flow in source loop 42 and/or load loops 43,44, respectively. Variable speed pumps may be driven by a PWM signal according to a predetermined duty cycle to control the speed of the pumps and therefore the discharge flow rate of these pumps.
Controller 36 may be configured to (wired or wirelessly) communicate with reversing valve 3 to control the direction of refrigerant flow in refrigerant circuit 40.
Controller 36 may be configured to (wired or wirelessly) communicate with the one or more thermostats 195 (e.g., an outdoor thermostat and/or one or more indoor thermostats for temperature controlled zones) for (1) detecting temperature differences between an outdoor temperature and an indoor temperature, and (2) for processing calls for space heating, space cooling, and/or water heating according to preprogrammed settings or manual, on-the-fly settings received from a user.
Controller 36 may be configured to (wired or wirelessly) communicate with the one or more temperature sensors 190 for detecting and processing the temperature at any one or more desired locations along refrigeration circuit 40, including at any one or more desired locations along source loop 37 and at any one or more desired locations along load loops 43,44.
Controller 36 may be configured to (wired or wirelessly) communicate with the one or more pressure sensors 191 for detecting and processing the static pressure at any one or more desired locations along refrigeration circuit 40.
Controller 36 may be configured to (wired or wirelessly) communicate with the one or more flow rate sensors 192 for detecting and processing the flow rate of water or other liquid along source loop 37 and/or along load loops 43,44.
Controller 36 may be configured to wired or wirelessly communicate with the one or more voltage sensors 193 for detecting and processing the voltage across any electrical device that consumes electrical energy in expansion valves 8,14. For example, one or more voltage sensors may be deployed to detect the voltage provided to compressor 1, pumps 131,132,133 reversing valve 3, motor that drives expansion valves 8,14, and the one or more motors that drive the one or more fans 33,34,35.
Controller 36 may be configured to wired or wirelessly communicate with the one or more current sensors 194 for detecting and processing the current drawn by any device in modular chiller system 100 that consumes electrical energy. For example, one or more current sensors may be deployed to detect the current drawn by compressor 1, pumps 131,132,133 (if present), reversing valve 3, motor that drives expansion valves 8,14, and the one or more motors that drive the one or more fans 33,34,35.
Controller 36 may be configured to wired or wirelessly communicate with a remote master controller 48 configured to manage the operation of multiple units of modular chiller systems of the instant disclosure. Similarly, controller 36 may be configured to wired or wirelessly communicate with a remote computer or database 45 via wired Ethernet, Wi-Fi, or Bluetooth with or without an Internet connection 46. Controller 36 may also be configured to wired or wirelessly communicate with a handheld device 47, such as a mobile phone, tablet, and the like.
Turning to
In this example, each of modules 270, 271, and 272 comprise any of the modular chiller systems of the instant disclosure, such as modular chiller system 100. In addition, each of modules 270, 271, and 272 are individually connected to a conduit module 250 configured for conveying heated and/or chilled water or other liquid to and from heating/cooling loads 30,32 and which form a part of loops 43,44. Conduit module 250 includes (i) conduit 261 for conveying heated water (or other liquid as the case may be) that has been heated by load heat exchanger 4 to load 30, (ii) conduit 262 for returning the water (or other liquid as the case may be) from load 30 to load heat exchanger 4, (iii) conduit 263 for conveying chilled water (or other liquid as the case may be) that has been cooled by load heat exchanger 18 to load 32, and (iv) conduit 264 for returning the water (or other liquid as the case may be) from load 32 to load heat exchanger 18.
In this example, valves 29,31 of modular chiller system 100 of respective modules 270, 271, and 272 are replaced by valves 29a,29b and 31a,31b, respectively, to control the flow of water (or other liquid as the case may be) to and from load heat exchangers 4,18, respectively, and to and from load loops 44,43, respectively, via conduits 262,261,264,263, respectively, of conduit module 250. In addition, in this example, the one or more fans 34 are shown schematically as fans 34a,34b for exchanging heat with the refrigerant conveyed through source heat exchangers 26.
In the illustrated example of
In this way, an example 3-unit bank of modular chiller systems of the instant disclosure (or 3 modular chiller systems positioned non-adjacently with one another in, on, or near the building or structure) can simultaneously supply chilled water alone from one unit, heated water alone from another unit, and simultaneously supply heated and chilled water from yet another unit to meet the heating and cooling loads of the building, structure, and/or industrial processes.
As shown in
While specific embodiments have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the disclosure herein is meant to be illustrative only and not limiting as to its scope and should be given the full breadth of the appended claims and any equivalents thereof.
