Patent Application
20180292112
This application relates to optimization of a heating ventilation and air conditioning (HVAC) system and more particularly, but not by way of limitation, to optimization of an HVAC system during part-load operation utilizing a de-superheated condenser circuit, unequal compressor sizes, and an unequal face split evaporator coil.
Several industry standards and federal regulations specify minimum acceptable efficiency of heating, ventilation, and air conditioning (HVAC) systems. Traditionally, HVAC system efficiency has been measured at full-load operating conditions. Efficiency at full-load operating conditions could be improved by adjusting the size of the condenser coils or the size of the compressor. Under current guidelines, however, more emphasis is placed on operating efficiency at part-load operating conditions. Thus, it becomes a challenge to increase efficient performance in an HVAC system that is already at maximum capacity. One approach is to utilize variable air volume designs in order to reduce air volume and power consumption during part-load operating conditions. However, it has been found to be cost prohibitive to retro-fit existing HVAC systems for variable air volume operation.
This application relates to optimization of a heating ventilation and air conditioning (HVAC) system and more particularly, but not by way of limitation, to optimization of an HVAC system during part-load operation utilizing a de-superheated condenser circuit, unequal compressor sizes, and an unequal face split evaporator coil. In one aspect, the present invention relates to a condenser system. The condenser system includes a first compressor and a second compressor. An upper coil and a de-superheater coil are fluidly coupled to the first compressor. The upper coil, the de-superheater coil, and the first compressor define a first compressor circuit. A lower coil is fluidly coupled to the second compressor. The lower coil and the second compressor define a second compressor circuit. The upper coil and the de-superheater coil together utilize an entire heat-transfer surface area.
In another aspect, the present invention relates to an evaporator system. The evaporator system includes a high-capacity evaporator coil fluidly coupled to a high-capacity refrigerant line. A low-capacity evaporator coil is fluidly coupled to a low-capacity refrigerant line. A solenoid valve is fluidly coupling the high-capacity refrigerant line to the low-capacity refrigerant line. The solenoid valve is closed responsive to a reduced mass flow rate of refrigerant. The solenoid valve, when closed, restricts flow of refrigerant to the high-capacity evaporator coil.
In another aspect, the present invention relates to a method of improving HVAC efficiency. The method includes arranging an upper coil above a lower coil. A de-superheater coil is arranged downstream of the lower coil. The upper coil and the de-superheater are fluidly coupled coil to a first compressor thereby defining a first compressor circuit. The lower coil is fluidly coupled to a second compressor thereby defining a second compressor circuit.
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 circulation fan 10, a gas heat 20, electric heat 22 typically associated with the circulation fan 10, and a refrigerant evaporator coil 30, also typically associated with the circulation fan 10. In various embodiments, the circulation fan 10 may be a single-speed circulation fan or a variable-speed circulation fan. The 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 47. The HVAC system 1 also includes a 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 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 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 compressor 40 may be a compressor system including at least two compressors of the same or different capacities. In some embodiments, the 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 47.
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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 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 47. 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 47.
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 circulation fan 10 or the plurality of environment sensors 60.
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An HVAC system equipped with a multi-stage or variable speed compressor and a constant-air-volume blower will become unable to maintain a suitable ratio of sensible capacity to total capacity (S/T) as the refrigerant flow rate decreases. In constant-air-volume systems, a decrease in refrigerant flow rate will cause the S/T ratio to rise. Systems having an S/T ratio above approximately 80% are generally considered unsuitable. The use of the high-capacity coil 704, the low-capacity coil 706, and the solenoid valve 702 enables the evaporator system 700 to preserve the S/T ratio at acceptable levels during part-load operation.
During periods when an HVAC compressor system such as, for example, the condenser system 200 is operating at part load or with reduced refrigerant flow rate, electrical current to the solenoid valve 702 is interrupted thereby causing the solenoid valve 702 to close and prevent refrigerant flow to the high-capacity coil 704. Limiting refrigerant flow to only the low-capacity coil 706 allows a reduced refrigerant mass flow rate to maintain a required coil temperature in the low-capacity coil 706 necessary to maintain a desired S/T ratio.
Although various embodiments of the method and system of the present invention have been illustrated in the accompanying Drawings and described in the foregoing Specification, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit and scope of the invention as set forth herein. It is intended that the Specification and examples be considered as illustrative only.
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 be 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.
