The presently disclosed embodiments generally relate to heating, ventilation, air conditioning and refrigeration (“HVAC&R”) systems, and more particularly, to a two phase loop distributed HVAC&R system.
Typically, buildings contain HVAC&R systems that include either roof top units or chillers for cooling operation, and direct gas-fired units or boilers for heating operation. In some instances, there is a requirement to simultaneously heat and cool different areas of the building. Typically, conventional HVAC systems incur energy waste by reheating cooled air to maintain comfort for the areas that require heating operation. Typically, these systems use a single phase heat transfer loop, operate at a single temperature lift, and are inefficient at transferring heat between different areas of the building.
Accordingly, there exists a need for a system that can efficiently heat and cool a building simultaneously.
In one aspect, an HVAC&R system is provided. The HVAC&R system includes a pumping device configured to circulate a first two-phase medium, a plurality of secondary HVAC&R units, wherein at least one of the plurality of secondary is operably coupled to the pumping device, and a primary HVAC&R unit operably coupled to at least one of the plurality of secondary HVAC&R units and the pumping device. The pumping device, a portion of each of the plurality of secondary HVAC&R units, and a portion of the primary HVAC&R unit form a primary loop. In an embodiment, the HVAC&R system further includes a valve operably coupled to the pumping device, the valve configured to direct the flow of the first two-phase medium
In any embodiment, the HVAC&R system further includes a controller in electrical communication with the pumping device, the valve, each of the plurality of secondary HVAC&R units, and the primary HVAC&R unit. The controller is configured to control the operation of each of the plurality of secondary HVAC&R, the first pumping device, the first valve and the primary HVAC&R unit.
In any embodiment, the HVAC&R system further includes at least one sensing device disposed on the primary loop. The at least one sensing device is configured to determine the state of the first two-phase medium.
In any embodiment, each of the plurality of secondary HVAC&R units include a secondary compressor configured to circulate a second two-phase medium, a first secondary heat exchanger operably coupled to the secondary compressor, a secondary expansion device operably coupled to the first secondary heat exchanger, and a second secondary heat exchanger operably coupled to the secondary expansion device and the secondary compressor. A portion of the primary loop is operably coupled to the first secondary heat exchanger.
In any embodiment, the primary HVAC&R unit includes a primary compressor configured to circulate a third two-phase medium, a first primary heat exchanger operably coupled to the primary compressor, a primary expansion device operably coupled to the first primary heat exchanger, and a second primary heat exchanger operably coupled to the primary expansion device and the primary compressor. A portion of the primary loop is operably coupled to the first primary heat exchanger.
In any embodiment, the first two-phase medium includes carbon dioxide. In any embodiment, the second two-phase medium and the third two-phase medium include a refrigerant.
In any embodiment, each of the plurality of secondary HVAC&R units includes a heat pump. In any embodiment, each of the plurality of secondary HVAC&R units is configured to operate in at least one of a heating mode and cooling mode.
In any embodiment, the primary HVAC&R unit includes a heat pump. In any embodiment, the primary HVAC&R unit is configured to operate in at least one of a heating mode and cooling mode.
In any embodiment, the HVAC&R system further includes an airflow device disposed on the primary loop. The airflow device is configured to direct airflow onto the primary loop. In any embodiment, the HVAC&R system further includes at least one conduit operably coupled to at least one of the plurality of secondary HVAC&R units, and an airflow device operably coupled to the at least one conduit. The airflow device is configured to circulate outdoor air to the at least one of the plurality of secondary HVAC&R units.
In any embodiment, the pumping device is configured to operate at a pumping capacity, each of the plurality of secondary HVAC&R units is configured to operate at a secondary capacity, and the primary HVAC&R unit is configured to operate at a primary capacity. In one embodiment, the controller is configured to vary at least one of the pumping capacity, the secondary capacity and the primary capacity. In one embodiment, varying at least one of the pumping capacity, the secondary capacity and the primary capacity provides a saturated sub-cooled first medium entering the first pumping device.
In any embodiment, the HVAC&R system further includes a first storage device, including a first storage volume therein, disposed on the primary loop and in flow communication with the first pumping device, wherein the first storage device is configured to provide the saturated sub-cooled first medium entering the pumping device.
For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure is thereby intended.
The pumping device 14 is configured to circulate the first medium 21 through the primary loop 22, and valve 16 is configured to direct the flow of the first medium 21 in the primary loop 22. In an embodiment, the first medium 21 includes a first two-phase fluid. In an embodiment, the first two-phase fluid includes liquid carbon dioxide. For example, the first two-phase fluid may be at least 50 percent by weight of carbon dioxide. It will be appreciated that the first two-phase fluid may include a percentage weight less than 50 percent. In one embodiment, the first two-phase fluid may be any refrigerant. It will be appreciated that the pumping device 14 is further configured to maintain the first medium 21 in a two-phase state in the secondary loop to minimize heat losses.
The plurality of secondary HVAC&R units 18A-B are configured to condition the air within the plurality of interior spaces 12A-B. It will be appreciated that each of the plurality of secondary HVAC&R units 18A-B is capable of providing the capacity needed in each of the plurality of interior spaces 12A-B at a reduced temperature lift of the second medium 33A-B as it flows between the first secondary heat exchanger 28A-B and the second secondary heat exchanger 26A-B (as shown in
The HVAC&R system 10 further includes a controller 23 in electrical communication with the pumping device 14, the valve 16, each of the plurality of secondary HVAC&R units 18A-B, and the primary HVAC&R unit 20. The controller 23 is configured to control the operation of the primary HVAC&R unit 20, and the pumping device 14 to process, circulate and direct the flow of the first medium 21. In an embodiment, the controller 23 is further configured to control the operation of the valve 16 to direct the flow of the first medium 21.
In an embodiment, the controller 23 is configured to vary the capacity of at least one of the pumping device 14 and the primary HVAC&R unit 20 to conserve energy and reduce the temperature lift required to meet the required demand. In some embodiments, the capacity of the pumping device 14 and the primary HVAC&R unit 20 may be varied to ensure that the first medium 21 enters the pumping device 14 as saturated subcooled liquid. Based on pressure and temperature of the first medium 21 measured at the inlet of the pumping device 14, the controller 23 may adjust the speed of pumping device 14 in the primary loop 22 and the speed/stage of primary compressor 34 (shown in
In a cooling dominant mode, if the measured temperature of the first medium 21 is lower than a saturation temperature at a measured pressure by less than a given threshold, e.g., approximately 0.5° C., the controller 23 may decrease the speed of the pumping device 14 and increase the speed/stage of the primary compressor 34 if needed. If the measured temperature of the first medium 21 is lower than the saturation temperature at the measured pressure by more than a given threshold, e.g., approximately 5.0° C., the controller 23 may decrease the speed/stage of primary compressor 34 and increase the speed of pumping device 14 if needed.
In heating dominant mode, if the measured temperature of the first medium 21 is lower than a saturation temperature at a measured pressure by less than a given threshold, e.g., approximately 0.5° C., the controller 23 may decrease the speed/stage of primary compressor 34 and decrease the speed of the pumping device 14 if needed. If the measured temperature of the first medium 21 is lower than the saturation temperature at the measured pressure by more than a given threshold, e.g., approximately 5.0° C., the controller 23 may increase the speed of the pumping device 14 and increase the speed/stage of primary compressor 34, if needed. In some embodiments, a first storage device 15 including a first storage volume 17 may be used before the pumping device 14 for this purpose.
The primary HVAC&R unit 20 includes a primary compressor 34, a first primary heat exchanger 36, a second primary heat exchanger 38, and a primary expansion device 40 in flow communication with one another to form an independent third HVAC&R loop 42 in which a third medium 43 is circulated therethrough. In an embodiment, the third medium 43 includes a third two-phase fluid. In an embodiment, the third two-phase fluid includes a refrigerant.
The HVAC&R system 10 is configured such that the primary loop 22 passes through the first secondary heat exchanger 28 of each of the plurality of secondary HVAC&R units 18A-B and through the first primary heat exchanger 36.
For an illustration of operation of the HVAC&R system 10, assume interior space 12B has a cooling demand greater than a heating demand for interior space 12A. It will be appreciated that the system 10 will determine the overall demand of the structure 13 as a function of a heating demand, cooling demand, or a combination of the demand of the plurality of interior spaces 12A-B. When the cooling demand is greater, controller 23 transmits a signal to the primary HVAC&R unit 20 to operate in a cooling mode. As such, the primary compressor 34 begins to pump high-pressure, high-temperature third medium 43 vapor into the second primary heat exchanger 38. The third medium 43 is cooled into high-pressure, high-temperature liquid and goes through the primary expansion device 40 where it becomes low-pressure, low-temperature two phase fluid. Thereafter, the low-pressure, low-temperature two phase fluid enters the first primary heat exchanger 36. Simultaneously, pumping device 14 circulates the first medium 21 through valve 16. The first medium 21 is directed through the first primary heat exchanger 36 and as the first medium 21 flows through the first primary heat exchanger 36 heat is exchanged from first medium 21 to the low-pressure, low-temperature two phase third medium 43.
The absorption of heat in the third medium 43 flowing through first primary heat exchanger 36 causes the third medium 43 to return to a low-pressure, low-temperature vapor state. The low-pressure, low-temperature vapor enters the primary compressor 34 where it turns into a high-pressure, high-temperature vapor. Thereafter, the high-pressure, high-temperature vapor enters the second primary heat exchanger 38 where the third medium 43 releases heat to external fluid, for example, ambient air, and condenses into a high-pressure, high-temperature liquid. The high-temperature liquid travels back through the expansion device 40 where it becomes low-pressure, low-temperature two phase fluid and returns to the primary heat exchanger 36.
To condition spaces 12A (heating) and 12B (cooling), the now cooled first medium 21 liquid is directed to the secondary HVAC&R unit 18B. Secondary HVAC&R unit 18B operates in a cooling mode due to the cooling demand in interior space 12B. As such secondary compressor 24B pumps high-pressure, high-temperature second medium 33B vapor through the first secondary heat exchanger 28B. The first medium 21 and the second medium 33B simultaneously flow through the first secondary heat exchanger 28B, and as a result, the second medium 33B vapor releases heat into the first medium 21 causing the first medium 21 to contain more vapor and causes the second medium 33B to return to a high-pressure, high-temperature liquid state.
The now high-pressure, high-temperature second medium 33B liquid enters the secondary expansion device 30B where it turns into a low-pressure, low-temperature two phase fluid. Thereafter, the low-pressure, low-temperature two phase fluid enters the second secondary heat exchanger 26B where fan 46B blows air across the second secondary heat exchanger 26B to send cool air into interior space 12B.
The two phase first medium 21 continues to flow to the secondary HVAC&R unit 18A. The secondary HVAC&R unit 18A is operating in a heating mode to condition the interior space 12A. Here, the secondary compressor 24A pumps high-pressure, high temperature second medium 33A vapor through a reversing valve (not shown), and the high-pressure, high-temperature refrigerant vapor flows through the second secondary heat exchanger 26A. The second medium 33A releases heat in the air as fan 46A blows air across the second secondary heat exchanger 26A to send warm air into interior space 12A. The second medium 33A turns into a high-pressure, high-temperature liquid when it enters secondary expansion device 30A where it changes state to a low-pressure, low-temperature two phase fluid and enters the first secondary heat exchanger 28A.
The first medium 21 and the second medium 33A simultaneously flow through the first secondary heat exchanger 28A, and as a result the low-pressure, low-temperature two-phase second medium 33A absorbs heat from the two phase first medium 21 to change the second medium 33A to a low-pressure, low-temperature vapor before it reenters the secondary compressor 24A. As a result, the temperature lift of the second medium 33A is effectively reduced; thus, increasing the efficiency of the HVAC&R system 10 and providing heat to space 18A.
As the heat from the first medium 21 is absorbed into the second medium 33A, the first medium 21 returns to a liquid state where it reenters the first primary heat exchanger 36 to begin the cycle again. It will be appreciated that the flow of the first medium 21, the second medium 33A-B, and the third medium 43 may be reversed depending on the mode of operation (i.e., heating or cooling).
For example, the flow of the first medium 21, the second medium 33A-B, and the third medium 43 in an all heating mode is shown in
For example, the flow of the first medium 21, the second medium 33A-B, and the third medium 43 in an all cooling mode is shown in
In some embodiments, a sensing device 48 (as shown in
As shown in the embodiment of
As shown in the embodiment of
In one embodiment, as shown in
Placing a portion(s) of the secondary HVAC&R units 18A-B within the interior space 12A-B, respectively and/or secondary interior space 60 is operable to mitigate the risks associated with the amount of the first medium 21 that may enter the occupied interior space 12A-B. For example, if there is a leak in the primary loop 22, the first medium 21 may be properly contained in a mechanically ventilated restricted area (secondary interior space 60) or naturally vented outside (as shown in
In an embodiment, as shown in
Using the second valve 62 and pressure container 64 is operable to maintain positive pressure within the primary loop 22 in cold ambient temperature conditions, and maintain the design pressure in hot ambient temperature conditions by preventing non-condensable gases from leaking into the two-phase loop during extremely cold weather, and avoiding release during extremely hot weather. In other embodiments, the HVAC&R system 10 is operable to maintain positive pressure within the primary loop 22 in cold ambient temperature conditions, and maintain the design pressure in hot ambient temperature conditions by directing exhaust air over the storage device 15 to pre-heat or pre-cool the primary loop 22. It is also operable to maintain positive pressure within the primary loop 22 in cold ambient temperature conditions by operating the pump device 14.
In an embodiment, as shown in
By separating the vapor and the liquid of the two-phase fluid retuning to the primary HVAC unit 20, the second storage device 70, vapor conduit 74, and liquid conduit 76 operate to effectively reduce an overall charge of the two-phase fluid within the system 10. The overall system charge of the system 10 is reduced based on the vapor and liquid traveling at the same pressure drop within the vapor conduit 74 and liquid conduit 76, respectively. Because the liquid phase has a higher density than the vapor, the liquid conduit 76 may be smaller in size (i.e. diameter); thus, reducing the flow area.
In an embodiment, as shown in
Any “pump” or “pumping” term included in the present disclosure, such as the pumping device 14, refers to a fluid pumping device in one or more embodiments, and refers to a liquid and/or gas pumping device in one or more additional embodiments of the present disclosure. Further, any heat pump or heat pumping device described or identified herein may include a non-vapor, compression-based heat pumping device or another solid state heat pumping device in one or more embodiments, as well as a conventional heat pump device in one or more embodiments.
It will therefore be appreciated that the present embodiments include an HVAC&R system 10 including a two-phase fluid flowing through a primary loop 22 to interconnect a primary HVAC&R unit 20 with independently controlled secondary HVAC&R units 18A-B to more efficiently heat and cool interior spaces 12A and 12B by effectively reducing the temperature lift of the second medium 33A-B within the plurality of secondary HVAC&R units 18A-B.
While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.
The present application is related to, and claims the priority benefit of, U.S. Provisional Patent Application Ser. No. 62/275,110 filed Jan. 5, 2016, and U.S. Provisional Patent Application Ser. No. 62/351,017, filed Jun. 16, 2016, the contents of which are hereby incorporated in their entirety by reference into the present disclosure.
Number | Name | Date | Kind |
---|---|---|---|
3264839 | Harnish | Aug 1966 | A |
4187543 | Healey | Feb 1980 | A |
4430866 | Willitts | Feb 1984 | A |
4732007 | Dolan et al. | Mar 1988 | A |
5366153 | Swenson | Nov 1994 | A |
5701750 | Ray | Dec 1997 | A |
5743110 | Laude-Bousquet | Apr 1998 | A |
5782101 | Dennis | Jul 1998 | A |
6170270 | Arshansky et al. | Jan 2001 | B1 |
6185946 | Hartman | Feb 2001 | B1 |
6453686 | Alden | Sep 2002 | B1 |
6467279 | Backman et al. | Oct 2002 | B1 |
6575233 | Krumnow | Jun 2003 | B1 |
6792766 | Osborne et al. | Sep 2004 | B2 |
6904760 | Butsch | Jun 2005 | B2 |
7150160 | Herbert | Dec 2006 | B2 |
7401472 | Manole | Jul 2008 | B2 |
7702423 | Steiner et al. | Apr 2010 | B2 |
7857233 | Trantham | Dec 2010 | B2 |
7900468 | Spearing | Mar 2011 | B2 |
8220531 | Murakami et al. | Jul 2012 | B2 |
8332075 | Harrod | Dec 2012 | B2 |
8539789 | Kopko | Sep 2013 | B2 |
8705423 | Salsbury et al. | Apr 2014 | B2 |
8733120 | Morimoto et al. | May 2014 | B2 |
8756943 | Chen et al. | Jun 2014 | B2 |
8844308 | Martin et al. | Sep 2014 | B2 |
9207001 | Roth | Dec 2015 | B1 |
9310087 | Grabon et al. | Apr 2016 | B2 |
9470435 | Hinde et al. | Oct 2016 | B2 |
20050133215 | Ziehr | Jun 2005 | A1 |
20060213219 | Beving | Sep 2006 | A1 |
20070056312 | Kobayashi | Mar 2007 | A1 |
20080289350 | Shapiro | Nov 2008 | A1 |
20100031697 | Hinde | Feb 2010 | A1 |
20100043475 | Taras et al. | Feb 2010 | A1 |
20100132399 | Mitra et al. | Jun 2010 | A1 |
20100242507 | Meckler et al. | Sep 2010 | A1 |
20110036113 | Kopko | Feb 2011 | A1 |
20110041523 | Taras et al. | Feb 2011 | A1 |
20110192189 | Morimoto et al. | Aug 2011 | A1 |
20120272669 | Blanton | Nov 2012 | A1 |
20130180278 | Yamashita | Jul 2013 | A1 |
20140033743 | Hancock | Feb 2014 | A1 |
20140223939 | Nasuta | Aug 2014 | A1 |
20140245762 | Schlesinger | Sep 2014 | A1 |
20140303835 | VerWoert | Oct 2014 | A1 |
20150007604 | Hu | Jan 2015 | A1 |
20150108230 | Cloonan et al. | Apr 2015 | A1 |
20150167994 | Josserand et al. | Jun 2015 | A1 |
20150178421 | Borrelli et al. | Jun 2015 | A1 |
20150260437 | Leman | Sep 2015 | A1 |
20160178244 | Delventura et al. | Jun 2016 | A1 |
20160245558 | Feng et al. | Aug 2016 | A1 |
20160258657 | Feng et al. | Sep 2016 | A1 |
Number | Date | Country |
---|---|---|
2014137971 | Nov 2014 | WO |
2015057297 | Apr 2015 | WO |
2015057299 | Apr 2015 | WO |
2015073122 | May 2015 | WO |
2015140151 | Sep 2015 | WO |
Number | Date | Country | |
---|---|---|---|
20170191711 A1 | Jul 2017 | US |
Number | Date | Country | |
---|---|---|---|
62275110 | Jan 2016 | US | |
62351017 | Jun 2016 | US |