Patent Application
20200318868
The present invention relates primarily to heating, ventilation, and air conditioning (“HVAC”) systems and more particularly, but not by way of limitation, to HVAC systems having multiple compressors with balanced fluid flow between the compressors.
Compressor systems are commonly utilized in HVAC applications. Many HVAC applications utilize compressor systems that comprise two or more parallel-connected compressors. Such multi-compressor systems allow an HVAC system to operate over a larger capacity than HVAC systems utilizing a single compressor. Frequently, however, multi-compressor systems are impacted by disproportionate fluid distribution between the compressors. Such disproportionate fluid distribution results in inadequate lubrication, loss of performance, and a reduction of useful life of the individual compressors in the multi-compressor system. Many present designs utilize mechanical devices, such as flow restrictors, to regulate fluid flow to each compressor. However, these mechanical devices are subject to wear and increased expense due to maintenance.
The present invention relates primarily to heating, ventilation, and air conditioning (“HVAC”) systems and more particularly, but not by way of limitation, to HVAC systems having multiple compressors with balanced fluid flow between the compressors. In a first aspect, the present invention relates to a compressor system. The compressor system includes at least two compressors. A suction equalizing tube fluidly couples the at least two compressors. A plumbing assembly fluidly couples to the first compressor and the second compressor. The plumbing assembly comprises an outlet to each compressor of the at least two compressors. A pressure differential between the at least two compressors is created so as to facilitate maintenance of a desired fluid level in the at least two compressors.
In another aspect, the present invention relates to a plumbing assembly. The plumbing assembly includes an inlet tube. A first main branch is fluidly coupled to the inlet tube. A second main branch is fluidly coupled to the inlet tube. A distribution section is fluidly coupled to the first main branch and to the second main branch. The distribution section includes a first outlet, a second outlet, and a third outlet. A first flow path is defined between the inlet tube and the first outlet. A second flow path is defined between the inlet tube and the second outlet. A third flow path is defined between the inlet tube and the third outlet. A desired pressure differential between first outlet, the second outlet, and the third outlet is created.
In another aspect, the present invention relates to a method of equalizing pressure in a multi-compressor system. The method includes determining a prescribed liquid level for at least two compressors and determining a liquid-level differential between the at least two compressors. A pressure drop for the at least two compressors that corresponds to the liquid-level differences is determined. An inlet tube is coupled to a main branch. A distribution section is coupled to the main branch. At least two compressors are coupled to the distribution section through at least a first outlet and a second outlet, respectively. The first outlet defines a first flow path between an inlet and the first outlet. The second outlet defines a second flow path between the inlet and the second outlet. A pressure drop is created in the first flow path and the second flow path that facilitates maintenance of the prescribed liquid level in the at least two compressors.
For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings in which:
Various embodiments of the present invention will now be described more fully with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
The HVAC system 1 includes a variable-speed circulation fan 10, a gas heat 20, electric heat 22 typically associated with the variable-speed circulation fan 10, and a refrigerant evaporator coil 30, also typically associated with the variable-speed circulation fan 10. The variable-speed circulation fan 10, the gas heat 20, the electric heat 22, and the refrigerant evaporator coil 30 are collectively referred to as an “indoor unit” 48. In a typical embodiment, the indoor unit 48 is located within, or in close proximity to, an enclosed space. The HVAC system 1 also includes a variable-speed compressor 40 and an associated condenser coil 42, which are typically referred to as an “outdoor unit” 44. In various embodiments, the outdoor unit 44 is, for example, a rooftop unit or a ground-level unit. The variable-speed compressor 40 and the associated condenser coil 42 are connected to an associated evaporator coil 30 by a refrigerant line 46. In a typical embodiment, the variable-speed compressor 40 is, for example, a single-stage compressor, a multi-stage compressor, a single-speed compressor, or a variable-speed compressor. Also, as will be discussed in more detail below, in various embodiments, the variable-speed compressor 40 may be a compressor system including at least two compressors of the same or different capacities. The variable-speed circulation fan 10, sometimes referred to as a blower, is configured to operate at different capacities (i.e., variable motor speeds) to circulate air through the HVAC system 1, whereby the circulated air is conditioned and supplied to the enclosed space 101.
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The HVAC controller 50 may be an integrated controller or a distributed controller that directs operation of the HVAC system 1. In a typical embodiment, the HVAC controller 50 includes an interface to receive, for example, thermostat calls, temperature setpoints, blower control signals, environmental conditions, and operating mode status for various zones of the HVAC system 1. In a typical embodiment, the HVAC controller 50 also includes a processor and a memory to direct operation of the HVAC system 1 including, for example, a speed of the variable-speed circulation fan 10.
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In a typical embodiment, the HVAC system 1 is configured to communicate with a plurality of devices such as, for example, a monitoring device 56, a communication device 55, and the like. In a typical embodiment, the monitoring device 56 is not part of the HVAC system. For example, the monitoring device 56 is a server or computer of a third party such as, for example, a manufacturer, a support entity, a service provider, and the like. In other embodiments, the monitoring device 56 is located at an office of, for example, the manufacturer, the support entity, the service provider, and the like.
In a typical embodiment, the communication device 55 is a non-HVAC device having a primary function that is not associated with HVAC systems. For example, non-HVAC devices include mobile-computing devices that are configured to interact with the HVAC system 1 to monitor and modify at least some of the operating parameters of the HVAC system 1. Mobile computing devices may be, for example, a personal computer (e.g., desktop or laptop), a tablet computer, a mobile device (e.g., smart phone), and the like. In a typical embodiment, the communication device 55 includes at least one processor, memory and a user interface, such as a display. One skilled in the art will also understand that the communication device 55 disclosed herein includes other components that are typically included in such devices including, for example, a power supply, a communications interface, and the like.
The zone controller 80 is configured to manage movement of conditioned air to designated zones of the enclosed space. Each of the designated zones include at least one conditioning or demand unit such as, for example, the gas heat 20 and at least one user interface 70 such as, for example, the thermostat. The zone-controlled HVAC system 1 allows the user to independently control the temperature in the designated zones. In a typical embodiment, the zone controller 80 operates electronic dampers 85 to control air flow to the zones of the enclosed space.
In some embodiments, a data bus 90, which in the illustrated embodiment is a serial bus, couples various components of the HVAC system 1 together such that data is communicated therebetween. In a typical embodiment, the data bus 90 may include, for example, any combination of hardware, software embedded in a computer readable medium, or encoded logic incorporated in hardware or otherwise stored (e.g., firmware) to couple components of the HVAC system 1 to each other. As an example and not by way of limitation, the data bus 90 may include an Accelerated Graphics Port (AGP) or other graphics bus, a Controller Area Network (CAN) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT) interconnect, an INFINIBAND interconnect, a low-pin-count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a serial advanced technology attachment (SATA) bus, a Video Electronics Standards Association local (VLB) bus, or any other suitable bus or a combination of two or more of these. In various embodiments, the data bus 90 may include any number, type, or configuration of data buses 90, where appropriate. In particular embodiments, one or more data buses 90 (which may each include an address bus and a data bus) may couple the HVAC controller 50 to other components of the HVAC system 1. In other embodiments, connections between various components of the HVAC system 1 are wired. For example, conventional cable and contacts may be used to couple the HVAC controller 50 to the various components. In some embodiments, a wireless connection is employed to provide at least some of the connections between components of the HVAC system such as, for example, a connection between the HVAC controller 50 and the variable-speed circulation fan 10 or the plurality of environment sensors 60.
Where m is the maldistribution value, m1 is the mass flow rate at a particular outlet, and mav is the ideal mass flow rate in the case of uniform flow. Thus, uniform fluid distribution between the first outlet 104, the second outlet 106, and the third outlet 108 will result in a maldistribution value of 0.
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In a typical embodiment, the alternative plumbing assembly 400 creates a pressure differential between the first outlet 410, the second outlet 412, and the third outlet 414 that facilitates maintenance of a prescribed liquid level in the first compressor 201, the second compressor 203, and the third compressor 205. In various embodiments, features such as tubing diameter, number of tubing bends, or flow restrictors can be utilized to create the desired pressure differential.
At step 512, an inlet 102 is fluidly coupled to a main branch. For example, in a three compressor system, the inlet 202 is fluidly coupled to a first main branch 204 and a second main branch 206. At step 514, a distribution section 208 is fluidly coupled to the main branch. For example, in a three compressor system the distribution section 208 is fluidly coupled to the first main branch 204 and the second main branch 206. At step 516, compressors are coupled to the distribution section 208. For example, in a three-compressor system, the first compressor 201, the second compressor 203, and the third compressor 205 are fluidly coupled to the first outlet 210, the second outlet 212, and the third outlet 214 of the distribution section 208, respectively. Thus, a first flow path 220 is defined between the inlet 102 and the first outlet 210, a second flow path 222 is defined between the inlet 102 and the second outlet 212, and a third flow path 224 is defined between the inlet 102 and the third outlet 214. At step 518, fluid flow through each branch is modified to achieve the pressure differentials calculated in step 506. For example, in a three-compressor system, fluid flow through the second flow path 222 is restricted relative to the first flow path 220 and the third flow path 224.
Step 518 is repeated to create the desired pressure differential to each compressor. At step 520, modification of the fluid flow through each branch creates a desired differential pressure between each compressor and facilitates maintenance of a prescribed liquid. level in each compressor. In a typical embodiment, pressure drop proportional to compressor capacity leads to prescribed liquid levels in the first compressor 201, the second compressor 203, and the third compressor 205 thereby enhancing efficiency and service life of the first compressor 201, the second compressor 203, and the third compressor 205. The process 500 ends at step 522.
Depending on the embodiment, certain acts, events, or functions of any of the algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all described acts or events are necessary for the practice of the algorithms). Moreover, in certain embodiments, acts or events can be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially. Although certain computer-implemented tasks are described as being performed by a particular entity, other embodiments are possible in which these tasks are performed by a different entity.
Conditional language used herein, such as, among others, “can,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.
While the above detailed description has shown, described, and pointed out novel features as applied to various embodiments, it will he understood that various omissions, substitutions, and changes in the form and details of the devices or algorithms illustrated can be made without departing from the spirit of the disclosure. As will be recognized, the processes described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others. The scope of protection is defined by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
This application is a continuation of and incorporates by reference U.S. patent application Ser. No. 15/464,470, filed on Mar. 21, 2017. This patent application incorporates by reference for any purpose the entire disclosure of U.S. patent application Ser. No. 15/464,606, filed on Mar. 21, 2017
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15464470 | Mar 2017 | US |
| Child | 16907522 | US |
