US20230003414A1

US20230003414A1 - Displacement ventilation systems and methods

Info

Publication number: US20230003414A1
Application number: US17/856,712
Authority: US
Inventors: Nicholas J. Searle; Matthew B. McLaurin; David M. Sanders; Randal S. Zimmerman; Kenneth J. Loudermilk
Original assignee: Air Distribution Technologies IP LLC
Current assignee: Air Distribution Technologies IP LLC
Priority date: 2021-07-02
Filing date: 2022-07-01
Publication date: 2023-01-05

Abstract

A heating, ventilation, and/or air conditioning (HVAC) system includes an air handling unit configured to condition an outdoor air flow to generate a ventilation air flow. The HVAC system includes a terminal unit fluidly coupled to the air handling unit. The terminal unit includes a plenum configured to receive the ventilation air flow and a blower configured to draw a return air flow from a space serviced by the HVAC system across a heat exchanger of the terminal unit and into the plenum to condition the return air flow. The blower is configured to mix the ventilation air flow and the return air flow to generate a supply air flow. A displacement ventilation (DV) diffuser is configured to receive the supply air flow. The DV diffuser is configured to direct the supply air flow through a filter of the DV diffuser and into the space.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of U.S. Provisional Application No. 63/218,044, entitled “AN HVAC SYSTEM,” filed Jul. 2, 2021, which is herein incorporated by reference in its entirety for all purposes.

BACKGROUND

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
A heating, ventilation, and/or air conditioning (HVAC) system may be used to regulate climate parameters within an environment, such as a building, home, or other structure. In some cases, an air handling unit of the HVAC system may direct a flow of fresh outdoor air into a building to provide ventilation and improved air quality within the building, while discharging a flow of return air from the building into an ambient environment, such as the atmosphere. Particularly, the air handling unit may include a fan assembly or other flow generating device that facilitates air circulation through the air handling unit and/or throughout ductwork of the building. In certain cases, one or more diffusers may be coupled to the ductwork and configured to direct a flow of supply air received from the air handling unit into the room, zone, or other space to be conditioned by the HVAC system. The diffusers are typically located near and/or coupled to a ceiling of the room and are configured to discharge the supply air generally toward a floor of the room from the ceiling. Unfortunately, such air discharge from the diffusers may generate turbulence (e.g., air vortices) within the room, which may increase spread and/or distribution of foreign matter (e.g., airborne particulates, contaminants) through the room.

SUMMARY

The present disclosure relates to a heating, ventilation, and/or air conditioning (HVAC) system. The HVAC system includes an air handling unit configured to condition an outdoor air flow to generate a ventilation air flow. The HVAC system also includes a terminal unit fluidly coupled to the air handling unit. The terminal unit includes a plenum configured to receive the ventilation air flow and a blower configured to draw a return air flow from a space serviced by the HVAC system across a heat exchanger of the terminal unit and into the plenum to condition the return air flow. The blower is configured to mix the ventilation air flow and the return air flow to generate a supply air flow. The HVAC system includes a displacement ventilation (DV) diffuser fluidly coupled to the terminal unit and configured to receive the supply air flow. The DV diffuser is configured to receive a filter configured to filter the supply air flow. The DV diffuser is configured to direct the supply air flow through the filter and into the space.
The present disclosure also relates to a displacement ventilation (DV) diffuser. The DV diffuser includes an enclosure having an inlet configured to receive an air flow and an outlet configured to discharge the air flow. The enclosure is configured to receive a high efficiency particulate air (HEPA) filter such that the HEPA filter extends across the outlet and is configured to filter the air flow. The DV diffuser also includes a grille removeably coupled to the enclosure and configured to secure the HEPA filter to the enclosure.
The present disclosure also relates to a heating, ventilation, and/or air conditioning (HVAC) system. The HVAC system includes an air handling unit having a first heat exchanger configured to dehumidify an outdoor air flow to generate a ventilation air flow. The HVAC system includes a terminal unit configured to receive the ventilation air flow. The terminal unit includes a second heat exchanger configured to circulate a working fluid and a blower configured to draw a return air flow across the second heat exchanger to condition the return air flow and to mix the return air flow with the ventilation air flow to generate a supply air flow. The HVAC system also includes a displacement ventilation (DV) diffuser configured to receive the supply air flow. The DV diffuser includes a filter configured to filter the supply air flow, where the filter includes a high efficiency particulate air (HEPA) filter.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which:

FIG. 1 is a perspective view of an embodiment of a building utilizing a heating, ventilation, and/or air conditioning (HVAC) system in a commercial setting, in accordance with an aspect of the present disclosure;

FIG. 2 is a schematic of an embodiment of an airside system including an air handling unit (AHU), in accordance with an aspect of the present disclosure;

FIG. 3 is a block diagram of an embodiment of an AHU controller, in accordance with an aspect of the present disclosure;

FIG. 4 is a schematic of an embodiment of an HVAC system having a displacement ventilation (DV) diffuser, in accordance with an aspect of the present disclosure;

FIG. 5 is a perspective view of an embodiment of a portion of an HVAC system having a DV diffuser, in accordance with an aspect of the present disclosure; and

FIG. 6 is a cross-sectional view of an embodiment of a DV diffuser, in accordance with an aspect of the present disclosure.

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will be described below. These described embodiments are only examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
As briefly discussed above, a heating, ventilation, and/or air conditioning (HVAC) system may be used to regulate certain climate parameters within a space of a building, home, or other suitable structure. For example, the HVAC system may include an air handling unit having a fan or other flow generating device that is positioned within an enclosure of the air handling unit. The enclosure may be in fluid communication with the building or other structure via an air distribution system, such as a system of ductwork, which extends between the enclosure and the building. The fan may be operable to force an air flow along an interior of the enclosure and, thus, direct air into or out of the building and/or via the air distribution system. In particular, the fan may enable the air handling unit to exhaust return air from the building and/or to direct fresh outdoor air into the building. Accordingly, a supply of fresh air may be circulated through an interior of the building to improve or maintain an air quality within the building.
Typically, the HVAC system includes one or more diffusers that are fluidly coupled to terminal ends of the ductwork and are configured to facilitate distribution of air from the ductwork into the rooms or spaces of the building. For example, the diffusers may be positioned adjacent to ceilings of the rooms conditioned by the HVAC system and may be configured to discharge air from the ductwork, into the rooms or other spaces, and in directions extending generally from the ceilings toward floors of the rooms or spaces serviced by the HVAC system. Discharge of air from the diffusers (e.g., from near the ceiling in a generally downward direction with respect to gravity) at a relatively high velocity may result in the formation of turbulence (e.g., air vortices) within the room or space. As such, the diffusers may form a portion of an overhead mixed air distribution system, for example, which may be configured to facilitate mixing of air within the room or space serviced by the HVAC system. Unfortunately, such turbulent air mixing within the room or space may increase spread and/or distribution of foreign matter (e.g., airborne particulates, contaminants) throughout the room or space. As such, conventional HVAC systems may be unsuited or ill-equipped to facilitate cooling, heating, and/or ventilation of spaces in which turbulent air mixing is undesirable, such as rooms of a hospital environment or clean room, for example.
Moreover, typical HVAC systems may mix air flows received from different rooms, spaces, or other regions of the building during operation of the HVAC system, which may result in spread of foreign matter (e.g., airborne contaminants) between the different rooms, spaces, and/or regions of the building. For example, a typical air handling unit of the HVAC system (e.g., an economizer of the HVAC unit) may be configured to receive a first flow of return air from a first room or zone serviced by the HVAC system and to receive a second flow of return air from a second room or zone serviced by the HVAC system. The air handling unit may mix at least a portion of the first and second air flows with one another and with outdoor air received from an ambient environment (e.g., the atmosphere) to form a supply air flow. The air handling unit may subsequently direct portions of the supply air flow back to the first and second rooms or zones. As a result, conventional HVAC systems may facilitate undesirable spread of foreign matter from the first room to the second room, and vice versa.
It is now recognized that it is desirable to facilitate conditioning (e.g., cooling, heating, ventilation, filtration) of spaces serviced by an HVAC system while also mitigating or substantially eliminating mixing (e.g., turbulent mixing) of air within each of the spaces, and while mitigating or substantially eliminating exchange of air between the spaces. Accordingly, embodiments of the present disclosure are directed toward an improved HVAC system that is configured to facilitate and enable displacement ventilation in the spaces serviced by the HVAC system to substantially reduce mixing (e.g., turbulent mixing) of air within the space, as compared to typical HVAC systems having overhead mixed air distribution systems. Moreover, the improved HVAC system disclosed herein is configured to mitigate or substantially eliminate exchange of air between individual rooms, zones, or other spaces serviced by the HVAC system to substantially inhibit transmission of foreign matter (e.g., airborne contaminants) between the individual spaces. These and other features will be described below with reference to the drawings.
Turning now to the drawings, FIG. 1 is a perspective view of an embodiment of a building 10 that may be serviced by a heating, ventilation, and/or air conditioning (HVAC) system 100. The HVAC system 100 may include a plurality of HVAC devices (e.g., heaters, chillers, air handling units, pumps, fans, thermal energy storage units, etc.) configured to provide heating, cooling, air conditioning, ventilation, and/or other services for the building 10. For example, in the illustrated embodiment, the HVAC system 100 is shown to include a waterside system 120 and an airside system 130. The waterside system 120 may provide a heated fluid and/or a chilled fluid to an air handling unit of the airside system 130. The airside system 130 may use the heated fluid and/or the chilled fluid to heat or cool an airflow provided to the building 10.
In the illustrated embodiment, the HVAC system 100 includes a chiller 102, a boiler 104, and an air handling unit (AHU) 106 (e.g., a rooftop unit). The waterside system 120 may use the boiler 104 and the chiller 102 to heat or cool a working fluid (e.g., water, glycol, etc.) and may circulate the working fluid to the AHU 106. In various embodiments, the HVAC devices of the waterside system 120 may be located in or around the building 10 or at an offsite location such as a central plant (e.g., a chiller plant, a steam plant, a heat plant, etc.) that serves one or more portions of the building 10. The working fluid may be heated in the boiler 104 or cooled in the chiller 102, depending on whether heating or cooling is desired in the building 10. The boiler 104 may add heat to the circulated fluid, for example, by burning a combustible material (e.g., natural gas) or using an electric heating element. The chiller 102 may place the circulated fluid in a heat exchange relationship with another fluid (e.g., a refrigerant) in a heat exchanger (e.g., an evaporator) to absorb heat from the circulated fluid. The working fluid from the chiller 102 and/or the boiler 104 may be transported to the AHU 106 via piping 108.
The AHU 106 may place the working fluid in a heat exchange relationship with an air flow passing through the AHU 106 (e.g., via one or more stages of cooling coils and/or heating coils). The air flow may be, for example, outside air, return air from within the building 10, or a combination of both. The AHU 106 may transfer heat between the air flow and the working fluid to provide heating or cooling for the air flow. For example, the AHU 106 can include one or more fans or blowers configured to pass the air flow over or through a heat exchanger containing the working fluid. The working fluid may then return to the chiller 102 and/or the boiler 104 via piping 110.
The airside system 130 may deliver the air flow supplied by the AHU 106 (i.e., the supply air flow) to the building 10 via air supply ducts 112 and may provide return air from the building 10 to the AHU 106 via air return ducts 114. In some embodiments, the airside system 130 includes multiple variable air volume (VAV) units 116. For example, in the illustrated embodiment, the airside system 130 is shown to include a separate VAV unit 116 on each floor or zone of building 10. The VAV units 116 may include dampers or other flow control elements that can be operated to control an amount of the supply air flow provided to individual zones of the building 10. In other embodiments, the airside system 130 delivers the supply air flow into one or more zones of the building 10 (e.g., via the supply ducts 112) without using the intermediate VAV units 116 or other flow control elements. The AHU 106 can include various sensors (e.g., temperature sensors, pressure sensors, etc.) configured to measure attributes of the supply air flow. The AHU 106 may receive input from sensors located within the AHU 106 and/or within the building zone and may adjust the flow rate, temperature, or other attributes of the supply air flow through the AHU 106 to achieve setpoint conditions for the building zone.
FIG. 2 is a schematic of an embodiment of an airside system 200, such as the airside system 130. The airside system 200 may include a subset of the HVAC devices that may be included in the HVAC system 100 (e.g., the AHU 106, the VAV units 116, the ducts 112, 114, fans, dampers, etc.) and may be located in or around the building 10. The airside system 200 may operate to heat or cool an air flow provided to the building 10 using a heated or chilled fluid provided by the waterside system 120.
In the illustrated embodiment of FIG. 2 , the airside system 200 is shown to include an economizer-type air handling unit (AHU) 202. The economizer-type AHU 202 may vary the amount of outside air and return air used by the air handling unit for heating or cooling. For example, the AHU 202 may receive return air 204 from building zone 206 via return air duct 208 and may deliver supply air 210 to the building zone 206 via supply air duct 212. In some embodiments, the AHU 202 (e.g., the AHU 106) is a rooftop unit located on the roof of the building 10 or otherwise positioned to receive both return air 204 and outside air 214. The AHU 202 may be configured to operate exhaust air damper 216, mixing damper 218, and outside air damper 220 to control an amount of the outside air 214 and the return air 204 is combined to form supply air 210. Any return air 204 that does not pass through mixing damper 218 may be exhausted from the AHU 202 through exhaust damper 216 as exhaust air 222.
Each of dampers 216, 218, 220 may be operated by an actuator. For example, the exhaust air damper 216 may be operated by actuator 224, mixing damper 218 may be operated by actuator 226, and outside air damper 220 may be operated by actuator 228. Actuators 224, 226, 228 may communicate with an AHU controller 230 via a communications link 232. The actuators 224, 226, 228 may receive control signals from the AHU controller 230 and may provide feedback signals to the AHU controller 230. Feedback signals can include, for example, an indication of a current actuator or damper position, an amount of torque or force exerted by the actuator, diagnostic information (e.g., results of diagnostic tests performed by actuators 224, 226, 228), status information, commissioning information, configuration settings, calibration data, and/or other types of information or data that can be collected, stored, or used by the actuators 224, 226, 228. The AHU controller 230 may be an economizer controller configured to use one or more control algorithms (e.g., state-based algorithms, extremum seeking control (ESC) algorithms, proportional-integral (PI) control algorithms, proportional-integral-derivative (PID) control algorithms, model predictive control (MPC) algorithms, feedback control algorithms, etc.) to control actuators 224, 226, 228.
In the illustrated embodiment of FIG. 2 , the AHU 202 is shown to include a cooling coil 234, a heating coil 236, and a fan 238 positioned within supply air duct 212. The fan 238 may be configured to force supply air 210 across the cooling coil 234 and/or the heating coil 236 and provide the supply air 210 to the building zone 206. The AHU controller 230 may communicate with the fan 238 via communications link 240 to control a flow rate of the supply air 210. In some embodiments, the AHU controller 230 controls an amount of heating or cooling applied to the supply air 210 by modulating a speed of the fan 238.
The cooling coil 234 may receive a chilled fluid from the waterside system 120 (via piping 242) and may return the chilled fluid to waterside system 120 via piping 244. A valve 246 may be positioned along the piping 242 or the piping 244 to control a flow rate of the chilled fluid through cooling coil 234. In some embodiments, the cooling coil 234 includes multiple stages of cooling coils that may be independently activated and deactivated (e.g., by the AHU controller 230, by supervisory controller 266, etc.) to modulate an amount of cooling applied to the supply air 210.
The heating coil 236 may receive a heated fluid from the waterside system 120 via piping 248 and may return the heated fluid to the waterside system 120 via piping 250. A valve 252 may be positioned along the piping 248 and/or the piping 250 to control a flow rate of the heated fluid through the heating coil 236. In some embodiments, the heating coil 236 includes multiple stages of heating coils that may be independently activated and deactivated (e.g., by the AHU controller 230, by the supervisory controller 266, etc.) to modulate an amount of heating applied to the supply air 210.
Each of the valves 246 and 252 may be controlled by an actuator. For example, valve 246 may be controlled by an actuator 254, and the valve 252 may be controlled by an actuator 256. The actuators 254, 256 may communicate with the AHU controller 230 via communications links 258, 260. The actuators 254, 256 may receive control signals from the AHU controller 230 and may provide feedback signals to the AHU controller 230. In some embodiments, the AHU controller 230 receives a measurement of the supply air temperature from a temperature sensor 262 positioned in the supply air duct 212 (e.g., downstream of the cooling coil 234 and/or the heating coil 236). The AHU controller 230 may also receive a measurement of the temperature of the building zone 206 from a temperature sensor 264 located in the building zone 206.
In some embodiments, the AHU controller 230 operates the valves 246 and 252 via the actuators 254, 256 to modulate an amount of heating or cooling provided to the supply air 210 (e.g., to achieve a setpoint temperature for the supply air 210 or to maintain the temperature of the supply air 210 within a setpoint temperature range). The positions of the valves 246 and 252 affect the amount of heating or cooling provided to the supply air 210 by the cooling coil 234 or the heating coil 236 and may correlate with the amount of energy consumed to achieve a desired supply air temperature. The AHU controller 230 may control the temperature of the supply air 210 and/or the building zone 206 by activating or deactivating the coils 234, 236, adjusting a speed of the fan 238, or a combination of both.
In the illustrated embodiment of FIG. 2 , the airside system 200 is shown to include a supervisory controller 266 and a client device 268. The supervisory controller 266 may include one or more computer systems (e.g., servers, supervisory controllers, subsystem controllers, etc.) that serve as system level controllers, application or data servers, head nodes, or master controllers for the airside system 200, the waterside system 120, the HVAC system 100, and/or other controllable systems that serve the building 10. The supervisory controller 266 may communicate with multiple downstream building systems or subsystems (e.g., the HVAC system 100, a security system, a lighting system, waterside system 120, etc.) via a communications link 270 according to like or disparate protocols (e.g., LON, BACnet, etc.). In various embodiments, the AHU controller 230 and the supervisory controller 266 may be separate or integrated. In an integrated implementation, the AHU controller 230 may be a software module configured for execution by a processor of the supervisory controller 266.
In some embodiments, the AHU controller 230 receives information from the supervisory controller 266 (e.g., commands, set points, operating boundaries, etc.) and provides information to the supervisory controller 266 (e.g., temperature measurements, valve or actuator positions, operating statuses, diagnostics, etc.). For example, the AHU controller 230 may provide the supervisory controller 266 with temperature measurements from the temperature sensors 262, 264, equipment on/off states, equipment operating capacities, and/or any other information that may be used by the supervisory controller 266 to monitor or control a variable state or condition within the building zone 206.
The client device 268 may include one or more human-machine interfaces or client interfaces (e.g., graphical user interfaces, reporting interfaces, text-based computer interfaces, client-facing web services, web servers that provide pages to web clients, etc.) for controlling, viewing, or otherwise interacting with the HVAC system 100, its subsystems, and/or devices. The client device 268 may be a computer workstation, a client terminal, a remote or local interface, or any other type of user interface device. The client device 268 may be a stationary terminal or a mobile device. For example, the client device 268 may be a desktop computer, a computer server with a user interface, a laptop computer, a tablet, a smartphone, a PDA, or any other type of mobile or non-mobile device. The client device 268 may communicate with supervisory the controller 266 and/or the AHU controller 230 via a communications link 272.
FIG. 3 is a schematic of an embodiment of the AHU controller 230. The AHU controller 230 may be configured to monitor and control various components of the AHU 202 using any of a variety of control techniques (e.g., state-based control, on/off control, proportional control, proportional-integral (PI) control, proportional-integral-derivative (PID) control, extremum seeking control (ESC), model predictive control (MPC), etc.). The AHU controller 230 may receive set points from the supervisory controller 266 and measurements from sensors 318 and may provide control signals to actuators 320 and the fan 238.
The sensors 318 may include any of the sensors shown in FIG. 2 and/or any other sensor configured to monitor any of a variety of variables used by the AHU controller 230. Variables monitored by the sensors 318 may include, for example, zone air temperature, zone air humidity, zone occupancy, zone carbon dioxide (CO2) levels, zone particulate matter (PM) levels, outdoor air temperature, outdoor air humidity, outdoor air CO2 levels, outdoor air PM levels, damper positions, valve positions, fan status, supply air temperature, supply air flow rate, or any other variable of interest to the AHU controller 230.
The actuators 320 may include any of the actuators shown in FIG. 2 and/or any other actuator controllable by the AHU controller 230. For example, the actuators 320 may include the actuator 224 configured to operate the exhaust air damper 216, the actuator 226 configured to operate the mixing damper 218, the actuator 228 configured to operate the outside air damper 220, the actuator 254 configured to operate the valve 246, and/or the actuator 256 configured to operate the valve 252. The actuators 320 may receive control signals from the AHU controller 230 and may provide feedback signals to the AHU controller 230.
The AHU controller 230 may control the AHU 202 by controllably changing and outputting a control signals provided to the actuators 320 and the fan 238. In some embodiments, the control signals include commands for the actuators 320 to set the dampers 216, 218, 220 and/or the valves 246 and 252 to specific positions to achieve a target value for a variable of interest (e.g., supply air temperature, supply air humidity, flow rate, etc.). In some embodiments, the control signals include commands for the fan 238 to operate at a specific operating speed and/or to achieve a specific air flow rate. The control signals may be provided to the actuators 320 and the fan 238 via a communications interface 302. The AHU 202 may use the control signals an input to adjust the positions of the dampers 216, 218, 220 control the relative proportions of the outside air 214 and the return air 204 provided to the building zone 206.
The AHU controller 230 may receive various inputs via the communications interface 302. Inputs received by the AHU controller 230 may include set points from the supervisory controller 266, measurements from the sensors 318, a measured or observed position of the dampers 216, 218, 220 or valves 246 and 252, a measured or calculated amount of power consumption, an observed fan speed, temperature, humidity, air quality, or any other variable that may be measured or calculated in or around the building 10.
The AHU controller 230 includes logic that adjusts the control signals to achieve a target outcome. In some operating modes, the control logic implemented by the AHU controller 230 utilizes feedback of an output variable. The logic implemented by the AHU controller 230 may also or alternatively vary a manipulated variable based on a received input signal (e.g., a set point). Such a set point may be received from a user control (e.g., a thermostat), a supervisory controller (e.g., the supervisory controller 266), or another upstream device via a communications network (e.g., a BACnet network, a LonWorks network, a LAN, a WAN, the Internet, a cellular network, etc.).
In the illustrated embodiment of FIG. 3 , the AHU controller 230 is shown to include the communications interface 302. The communications interface 302 may be or include wired or wireless communications interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wire terminals, etc.) for conducting data communications with various components of the AHU 202 or other external systems or devices. In various embodiments, communications via the communications interface 302 may be direct (e.g., local wired or wireless communications) or via a communications network (e.g., a WAN, the Internet, a cellular network, etc.). For example, the communications interface 302 can include an Ethernet card and port for sending and receiving data via an Ethernet-based communications link or network. In another example, the communications interface 302 may include a Wi-Fi transceiver for communicating via a wireless communications network. In another example, the communications interface 302 may include a cellular or mobile phone transceiver, a power line communications interface, an Ethernet interface, or any other type of communications interface.
The AHU controller 230 may include a processing circuit 304 having a processor 306 and a memory 308. The processor 306 may be a general purpose or specific purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable processing components. The processor 306 is configured to execute computer code or instructions stored in the memory 308 or received from other computer readable media (e.g., CDROM, network storage, a remote server, etc.).
The memory 308 may include one or more devices (e.g., memory units, memory devices, storage devices, etc.) for storing data and/or computer code for completing and/or facilitating the various processes described in the present disclosure. The memory 308 may include random access memory (RAM), read-only memory (ROM), hard drive storage, temporary storage, non-volatile memory, flash memory, optical memory, or any other suitable memory for storing software objects and/or computer instructions. The memory 308 may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. The memory 308 may be communicably connected to the processor 306 via the processing circuit 304 and may include computer code for executing (e.g., by the processor 306) one or more processes described herein.
The memory 308 may include any of a variety of functional components (e.g., stored instructions or programs) that provide the AHU controller 230 with the ability to monitor and control the AHU 202. For example, the memory 308 is shown to include a data collector 310 which operates to collect the data received via the communications interface 302 (e.g., set points, measurements, feedback from the actuators 320 and the fan 238, etc.). The data collector 310 may provide the collected data to an actuator controller 312 and a fan controller 314, which use the collected data to generate control signals for the actuators 320 and the fan 238, respectively. The particular type of control methodology used by the actuator controller 312 and the fan controller 314 (e.g., state-based control, PI control, PID control, ESC, MPC, etc.) may vary depending on the configuration of the AHU controller 230 and may be adapted for various implementations.
It should be appreciated that any of the features described herein may be incorporated with the HVAC system 100 or other HVAC systems. Additionally, while the features disclosed herein are described in the context of embodiments that directly heat and cool a supply air stream provided to a building or other load, embodiments of the present disclosure may be applicable to other HVAC systems as well. For example, the features described herein may be applied to mechanical cooling systems, free cooling systems, chiller systems, or other heat pump or refrigeration applications.
As briefly discussed above, embodiments of the present disclosure are directed to an improved HVAC system configured to facilitate conditioning (e.g., cooling, heating, ventilation, filtration) of spaces (e.g., rooms or zones of the building 10) serviced by the HVAC system while also mitigating or substantially eliminating mixing (e.g., turbulent mixing) of air within each of the spaces, and while mitigating or substantially eliminating exchange of air between the individual spaces. To provide context for the following discussion, FIG. 4 is a schematic of an embodiment of an HVAC system 400 configured to provide the aforementioned advantageous features. For clarity, it should be understood that the HVAC system 400 may include a portion of and/or all of the components of the HVAC system 100.
The HVAC system 400 includes an air handling unit 402 (e.g., the AHU 106, a dedicated outdoor air system [DOAS]) that may be fluidly coupled to a terminal unit 404 via first ductwork 406 (e.g., one or more conduits, a ventilation duct). The air handling unit 402 is configured to provide a flow of ventilation air 408 to the terminal unit 404 via the first ductwork 406. For example, the air handling unit 402 may include a first enclosure 410 configured to house or more climate management components of the air handling unit 402, such as a filter 412, a first heat exchanger 414 (e.g., an evaporator, a hydronic heat exchanger), a first blower 420, and/or other suitable climate management components of the air handling unit 402 (e.g., a heating coil, an electric furnace, a gas furnace). The first blower 420 may be operable to draw a flow of outdoor air 422 (e.g., from the atmosphere 424, from an outdoor environment) into the first enclosure 410 (e.g., via an inlet 426 of the first enclosure 410) and to direct the outdoor air 422 across one or more climate management components of the air handling unit 402. For example, the first blower 420 may direct the outdoor air 422 across the filter 412 and the first heat exchanger 414. As discussed in detail below, the first heat exchanger 414 may be configured to absorb thermal energy from the outdoor air 422 to enable generation of the ventilation air 408, which may have a temperature that is less than a temperature of the outdoor air 422. Moreover, the first heat exchanger 414 may cause condensation of moisture that may be suspended in the outdoor air 422 on a surface of the first heat exchanger 414. To this end, the first heat exchanger 414 may also facilitate dehumidification of the outdoor air 422, such that a relative humidity value of the ventilation air 408 discharged from the first heat exchanger 414 is less than a relative humidity value of the outdoor air 422 entering the air handling unit 402.
The terminal unit 404 includes a second enclosure 430 that may be fluidly coupled to the first enclosure 410 of the air handling unit 402 via the first ductwork 406. The first blower 420 may be operable to direct the ventilation air 408 through the first ductwork 406 and into the second enclosure 430 (e.g., into a plenum defined by the second enclosure 430). In some embodiments, the terminal unit 404 includes a second blower 432 configured to draw the ventilation air 408 from the air handling unit 402 into the second enclosure 430.
The terminal unit 404 may include a second heat exchanger 434. For example, the second heat exchanger 434 may be coupled to the second enclosure 430 and be disposed external to the second enclosure 430. In other embodiments, the second heat exchanger 434 may be disposed within an interior of the second enclosure 430 and/or be otherwise fluidly coupled to the interior of the second enclosure 430. The second blower 432 may be configured to draw a flow of return air 440 from a space (e.g., a room 442 or zone) to be conditioned by the HVAC system 400 and direct the return air 440 across the second heat exchanger 434 and into the second enclosure 430. As discussed below, the second heat exchanger 434 may be configured to facilitate cooling and/or heating of the return air 440 directed thereacross, such that the second heat exchanger 434 may output a flow of conditioned return air 444.
In some embodiments, the second heat exchanger 434 may be fluidly coupled to a chiller system 446 (e.g., HVAC system, heat pump) or another thermal management component via a supply line 448 (e.g., a chilled water supply line) and a return line 449 (e.g., a chilled water return line). The chiller system 446 may be configured to circulate a chilled working fluid (e.g., water, brine) through the second heat exchanger 434, such that the chilled working fluid may absorb thermal energy from the return air 440 that may be directed across the second heat exchanger 434 via the second blower 432. As discussed below, the second heat exchanger 434 may operate as a sensible cooling coil (e.g., at a temperature above a dew point temperature of the return air 440) to reduce a temperature of the return air 440 without substantially adjusting a humidity of the return air 440. As such, the second heat exchanger 434 may inhibit or substantially limit formation of condensation and/or accumulation of condensation on a surface of the second heat exchanger 434.
It should be appreciated that, in certain embodiments, the second heat exchanger 434 may be configured to circulate a heated working fluid, in lieu of a chilled working fluid, to facilitate heating of the return air 440 that may be directed across the second heat exchanger 434. Moreover, in some embodiments, operation of the second heat exchanger 434 may be temporarily suspended, such that the return air 440 may be directed across the second heat exchanger 434 without substantially cooling or heating of the return air 440. It should be understood that, as used herein, any air flow discharged from the second heat exchanger 434 may be referred to as the “conditioned return air 444.” That is, the conditioned return air 444 may be indicative of return air 440 that has been cooled by the second heat exchanger 434, return air 440 that has been heated by the second heat exchanger 434, and/or return air 440 that has been directed across the second heat exchanger 434 without being substantially cooled or heated by the second heat exchanger 434.
The terminal unit 404 may be configured to facilitate mixing of the ventilation air 408 received from the air handling unit 402 and the conditioned return air 444 discharged from the second heat exchanger 434. For example, the terminal unit 404 may include one or more baffles, passages, fans, dampers, or other components that may enhance or otherwise facilitate mixing of the ventilation air 408 and the conditioned return air 444. In any case, via mixing of the ventilation air 408 and the conditioned return air 444, the terminal unit 404 may generate of a flow of supply air 450 that may include at least a portion of the ventilation air 408 and at least a portion of the conditioned return air 444. The terminal unit 404 may be fluidly coupled to a third enclosure 452 (e.g., a housing) of a displacement ventilation (DV) diffuser 454 via second ductwork 456. As discussed below, the DV diffuser 454 may be positioned near or adjacent to a floor of the room 442 and be configured to discharge the supply air 450 into the room 442 and along the floor. To this end, the second blower 432 may be configured to direct the supply air 450 through the second ductwork 456, through the third enclosure 452 of the DV diffuser 454, and into the room 442 via an outlet 458 of the DV diffuser 454.
The DV diffuser 454 may be configured to accommodate (e.g., receive, support, contain) a filter 459 that extends across the outlet 458 of the DV diffuser 454. The filter 459 may be sealed to a perimeter of the outlet 458 via a gasket, bracket, harness, or other suitable seal. In some embodiments, the filter 412 may be a high efficiency particulate air (HEPA) filter configured to capture or trap, for example, 90 percent of particulate matter (e.g., foreign matter, airborne contaminants) suspended in an air flow (e.g., the supply air 450) directed across the filter 459, such as particulate matter having particles with a size between 1.0 microns and 3.0 microns in diameter.
In some embodiments, the terminal unit 404 may include a reheat coil 460 (e.g., a third heat exchanger) that may be operable in addition to, or in lieu of, the second heat exchanger 434 to increase a temperature of the supply air 450 prior to delivery of the supply air 450 to the DV diffuser 454. For example, the reheat coil 460 may be configured to receive a flow of heated working fluid (e.g., heated water) and enable the heated working fluid to reject heat (e.g., thermal energy) to the mixture of ventilation air 408 and conditioned return air 444 that may be directed across the reheat coil 460 via the second blower 432. As such, it should be understood that any one or combination of the first heat exchanger 414, the second heat exchanger 434, and the reheat coil 460 may be included in the HVAC system 400 and may be operable to facilitate adjustment in a temperature value and/or a humidity level of the supply air 450. Moreover, it should be appreciated that relative locations of any of the first and/or second heat exchangers 414, 434, the first and/or second blowers 420, 432, the reheat coil 460, and/or other components of the HVAC system 400 are not limited to the locations shown in the illustrated embodiment of FIG. 4 . As a non-limiting example, the second heat exchanger 434 may be located within the second enclosure 430, external to the second enclosure 430, adjacent to reheat coil 460, or at another suitable location. Similarly, the reheat coil 460 may be located within the second enclosure 430 or external to the second enclosure 430.
In some embodiments, the terminal unit 404 may include an additional filter 470 (e.g., a HEPA filter, a MERV-6 filter, a MERV-8 filter) configured to filter the return air 440 entering the terminal unit 404. For example, the additional filter 470 may be positioned adjacent to the second heat exchanger 434 and be configured to filter the return air 440 prior to the return air 440 being directed across the second heat exchanger 434. The terminal unit 404 may include an access panel to enable removal and/or replacement of the additional filter 470 via an occupant located within the room 442.
In some embodiments, the HVAC system 400 includes one or more sensors 480 configured to acquire feedback or other data indicative of one or more operational parameters of the HVAC system 400. For example, the one or more sensors 480 may include a first sensor 482 configured to acquire data or feedback indicative of a temperature and/or a humidity of the outdoor air 422, a second sensor 484 configured to acquire data or feedback indicative of a temperature and/or a humidity of the ventilation air 408, a third sensor 486 configured to acquire data or feedback indicative of a temperature and/or a humidity of the return air 440, a fourth sensor 488 configured to acquire data or feedback indicative of a temperature and/or a humidity of the conditioned return air 444, a fifth sensor 490 configured to acquire data or feedback indicative of a temperature and/or a humidity of the supply air 450, a sixth sensor 492 (e.g., a thermostat) configured to measure an ambient temperature and/or a humidity within the room 442, a seventh sensor 494 configured to measure a temperature of a working fluid 496 supplied to the second heat exchanger 434 (e.g., via the supply line 448), and/or other suitable sensor(s).
The HVAC system 400 may include a controller 500 (e.g., the AHU controller 230, a control system, a thermostat, a control panel, control circuitry) that is communicatively coupled to one or more components of the HVAC system 400 and is configured to monitor, adjust, and/or otherwise control operation of one or more components of the HVAC system 400. For example, one or more control transfer devices, such as wires, cables, wireless communication devices, and the like, may communicatively couple the first and/or second blowers 420, 432, the chiller system 446, the sensors 480, one or more dampers, one or more valves, and/or any other suitable components of the HVAC system 400 to the controller 500. The first and/or second blowers 420, 432, the chiller system 446, and/or the sensors 480 may each have one or more communication components that facilitate wired or wireless (e.g., via a network) communication with the controller 500. In some embodiments, the communication components may include a network interface that enables the components of the HVAC system 400 to communicate via various protocols such as EtherNet/IP, ControlNet, DeviceNet, or any other communication network protocol. Alternatively, the communication components may enable the components of the HVAC system 400 to communicate via mobile telecommunications technology, Bluetooth®, near-field communications technology, and the like. As such, the first and/or second blowers 420, 432, the chiller system 446, and/or the sensors 480 may wirelessly communicate data and/or control signals between each other.
In some embodiments, the controller 500 may be a component of or may include the AHU controller 230. In other embodiments, the controller 500 may be a standalone controller, a dedicated controller, or another suitable controller included in the HVAC system 400. In any case, the controller 500 is configured to control components of the HVAC system 400 in accordance with the techniques discussed herein. The controller 500 includes processing circuitry 502, such as a microprocessor, which may execute software (e.g., executable instructions, code) for controlling components of the HVAC system 400. The processing circuitry 502 may include multiple microprocessors, one or more “general-purpose” microprocessors, one or more special-purpose microprocessors, and/or one or more application specific integrated circuits (ASICS), or some combination thereof. For example, the processing circuitry 502 may include one or more reduced instruction set (RISC) processors.
The controller 500 may also include a memory device 504 (e.g., a memory) that may store information, such as instructions, control software, look up tables, configuration data, code, etc. The memory device 504 may include a volatile memory, such as random access memory (RAM), and/or a nonvolatile memory, such as read-only memory (ROM). The memory device 504 may store a variety of information and may be used for various purposes. For example, the memory device 504 may store processor-executable instructions including firmware or software for the processing circuitry 502 execute, such as instructions for controlling components of the HVAC system 400. In some embodiments, the memory device 504 is a tangible, non-transitory, machine-readable-medium that may store machine-readable instructions for the processing circuitry 502 to execute. The memory device 504 may include ROM, flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The memory device 504 may store data, instructions, and any other suitable data. As discussed in detail below, the controller 500 may be configured to control operation of the HVAC system 400 to facilitate conditioning (e.g., cooling, heating, ventilation, filtration) of the room 442 while mitigating or substantially eliminating mixing (e.g., turbulent mixing) of air within the room 442 and while mitigating or substantially eliminating exchange of air between the room 442 and other rooms that may be serviced by the HVAC system 400 (e.g., other rooms in the building 10).
To facilitate the following discussion, FIG. 5 is a perspective view of an embodiment of a portion of the HVAC system 400. In the illustrated embodiment, the HVAC system 400 includes an exhaust duct 510 (e.g., grille) configured to receive and direct exhaust air 512 from the room 442. For example, an exhaust fan 514 or blower may be configured to draw the exhaust air 512 through the exhaust duct 510 and discharge the exhaust air 512 to the atmosphere. It should be noted that the exhaust fan 514 may not recirculate the exhaust air 512 to another room, zone, or space within the building 10. In this manner, the HVAC system 400 may block or substantially inhibit transfer of the exhaust air 512, which may contain airborne contaminants, from the room 442 to another room of the building 10, for example, or vice versa. In other words, the air handling unit 402 and the terminal unit 404 may not receive the exhaust air 512 from the exhaust duct 510.
As shown in the illustrated embodiment of FIG. 5 , the DV diffuser 454 may be located adjacent to a floor 520 of the room 442. In some embodiments, a cross-sectional area of the outlet 458 and a cross-sectional area of the filter 459 may be relatively large. As a result, the outlet 458 and the filter 459 may enable supply of the supply air 450 to the room 442 at a relatively low velocity. In this way, the DV diffuser 454 may direct the supply air 450 along the floor 520 in a manner that mitigates air turbulence in the room 442, as discussed in further detail below.
The following discussion continues with concurrent reference to FIGS. 4 and 5 . As discussed above, the HVAC system 400 is configured to facilitate conditioning of the room 442 while mitigating or substantially eliminating mixing (e.g., turbulent mixing) of air within the room 442 and while mitigating or substantially eliminating exchange of air between the room 442 and other rooms serviced by the HVAC system 400 (e.g., other rooms in the building 10). The controller 500 may be configured to operate the HVAC system 400 to provide a desired amount of ventilation (e.g., air exchange) within the room 442 while also providing conditioning (e.g., cooling) to the room 442.
For example, to provide ventilation within the room 442, the controller 500 may operate the first blower 420 to draw outdoor air 422 into the first enclosure 410 of the air handling unit 402. In some embodiments, the controller 500 may receive feedback from the first sensor 482 indicative of temperature of the outdoor air 422 and/or of a humidity of the outdoor air 422. In response to a determination that a humidity level of the outdoor air 422 is above a target humidity level associated with the room 442, the controller 500 may instruct the air handling unit 402 to operate in a dehumidification mode to dehumidify the outdoor air 422. In particular, the controller 500 may operate components of the air handling unit 402 to circulate working fluid through the first heat exchanger 414 at a temperature that is below a dew point temperature of the outdoor air 422. As a result, water vapor (e.g., moisture) suspended in the outdoor air 422 may condense and be removed from the outdoor air 422, such that the ventilation air 408 output by the air handling unit 402 has a humidity level that is less than a humidity level of the outdoor air 422 entering the air handling unit 402. In some embodiments, the controller 500 may receive feedback indicative of the humidity level of the ventilation air 408 from the second sensor 484. The controller 500 may be configured to utilize feedback from the first sensor 482, the second sensor 484, or both, to operate components of the air handling unit 402 to achieve a humidity level of the ventilation air 408 that is substantially similar to or below (e.g., within a threshold range of, within a threshold percentage of) the target humidity level for the room 442.
As discussed below, the terminal unit 404 may be configured to facilitate conditioning (e.g., cooling) of the room 442 in addition to any cooling capacity that may be provided via the first heat exchanger 414 of the air handling unit 402. Accordingly, the air handling unit 402 may not be operated to satisfy an entire cooling demand of the room 442. Thus, an overall size of the air handling unit 402 may be reduced, as compared to typical air handling units. That is, the air handling unit 402 may primarily operate to dehumidify the flow of outdoor air 422, instead of operating to provide an amount of conditioned air that is suitable to satisfy the cooling demand of the room 442. In this way, a size of the first ductwork 406 configured to deliver the ventilation air 408 may also be reduced as compared to conventional systems.
In some embodiments, the air handling unit 402 may not receive a flow of the exhaust air 512 from the exhaust duct 510. That is, the air handling unit 402 may not include an energy recovery wheel or similar heat exchange device for transferring thermal energy between the exhaust air 512 and the outdoor air 422 and/or between the exhaust air 512 and the ventilation air 408. As a result, the HVAC system 400 may substantially reduce introduction of foreign matter (e.g., airborne contaminants) that may be included in the exhaust air 512 into the outdoor air 422 and/or the ventilation air 408. Further, via elimination of an energy recovery wheel or similar device in the air handling unit 402, an overall size of the air handling unit 402 may be further reduced (e.g., as compared to conventional air handling units having an energy recovery wheel). However, it should be appreciated that, in certain embodiments, the air handling unit 402 may indeed include an energy recovery wheel or similar heat exchange device. That is, the air handling unit 402 may receive at least a portion of an exhaust air flow from the building 10 and utilize the energy recovery wheel or similar device to pre-cool or pre-heat the outdoor air 422 entering the air handling unit 402, for example.
The controller 500 may operate the second blower 432 to draw the return air 440 across the additional filter 470, mix the filtered return air (e.g., the conditioned return air 444) with the ventilation air 408 to form the supply air 450, and direct the supply air 450 toward the DV diffuser 454. In some embodiments, the second blower 432 and the additional filter 470 may cooperate to reduce an amount of air changes that the air handling unit 402 may need to provide to achieve a particular air exchange in the room 442. As a non-limiting example, in a hospital or health care environment, it may be desirable to achieve four air changes per hour in the room 442. For clarity, as used herein, an “air change” of the room 442 or other space may refer to a complete or substantial replacement of air within the room 442 or other space with replenished air (e.g., fresh air, filtered air) supplied via the DV diffuser 454. Indeed, the replenished air may include outdoor air 442 and air from the room 422 that is re-filtered (e.g., via the terminal unit 402). For example, the air handling unit 402 may be operable to provide a volume of air to enable two air changes of the room 442 via the outdoor air 422 drawn into the HVAC system 400. The terminal unit 404 may be operable to provide an additional volume of air to enable the remaining two air exchanges of the room 442 via the return air 440 that is filtered via the additional filter 470. As such, via operation of the second blower 432 and the additional filter 470, the air handling unit 402 may be configured to provide a portion of the total volume of air to achieve the desired air changes for the room 442 (e.g., two air changes), instead of providing enough air to achieve the total number of air changes for the room 442 (e.g., four air changes). Accordingly, an overall size of the air handling unit 402 may be reduced, as compared to a system having an air handling unit configured to provide four air changes to the room 442, for example.
In some embodiments, the controller 500 may receive data or feedback indicative of a temperature (e.g., a current temperature) of the room 442 from the sixth sensor 492 (e.g., a thermostat). In response to a determination that the temperature in the room 442 exceeds a target temperature set point (e.g., a user-selected target temperature), the controller 500 may operate the second heat exchanger 434 to condition (e.g., reduce a temperature of) the return air 440 drawn into the terminal unit 404 (e.g., via the second blower 432).
For example, the controller 500 may operate the chiller system 446 or another suitable heat exchange system to provide conditioned fluid (e.g., the working fluid 496) to second heat exchanger 434 via the supply line 448. The controller 500 may control components of the HVAC system 400 to regulate a flow rate and/or a temperature of the chilled working fluid 496 supplied to the second heat exchanger 434 (e.g., via the supply line 448). In this way, the controller 500 may adjust a temperature of the conditioned return air 444 output by the second heat exchanger 434 and, thus, adjust (e.g., increase or decrease) the temperature of the supply air 450 directed into the room 442 (e.g., via the DV diffuser 454). The controller 500 may operate the second heat exchanger 434 in this manner to achieve a current temperature within the room 442 that is substantially equal to (e.g., within a threshold range of, within a threshold percentage of) the target temperature set point of the room 442. Additionally or alternatively, the controller 500 may adjust operation of the air handling unit 402 based on the feedback from the sixth sensor 492 to increase or decrease a temperature of the ventilation air 408 entering the terminal unit 404.
In any case, the controller 500 may operate the chiller system 446 such that a temperature of the second heat exchanger 434 (e.g., a surface temperature of the second heat exchanger 434) and/or a temperature of the supply line 448 (e.g., surface temperature of the supply line 448) remains above a dew point temperature of the return air 440 and/or above a dew point temperature of the existing air within the room 442. In this way, the controller 500 may ensure that the second heat exchanger 434 does not condense moisture that may be suspended within the return air 440 drawn thereacross, which may result in accumulation of condensate on and/or near the second heat exchanger 434. Further, to this end, the controller 500 may ensure that contact between the existing air within the room 442 and the supply line 448 does not result in the formation of condensate on the supply line 448. In other words, the controller 500 may enable dry cooling (e.g., sensible cooling) of the return air 440, which may reduce or substantially inhibit accumulation of impurities and/or organic matter on the second heat exchanger 434 and/or the supply line 448. As such, the controller 500 may increase a time interval between maintenance cycles of the HVAC system 400 (e.g., cleaning of one or more coils of the second heat exchanger 434) and may enhance sanitary operation of the HVAC system 400. Further, by providing sensible cooling via the second heat exchanger 434, condensate collection equipment such as drain pans, pipes, and/or pumps may be omitted from the terminal unit 404.
In some embodiments, the controller 500 may be configured to adjust operation of the chiller system 446 to ensure that a temperature of the chilled working fluid 496 output by the chiller system 446 remains above the dew point temperature of the return air 440 and/or above the dew point temperature of the existing air within the room 442. For example, in some embodiments, the controller 500 may be configured to receive data or feedback from the third sensor 486 indicative of a temperature and/or a humidity level of the return air 440. The controller 500 may utilize the feedback to calculate the dew point temperature of the return air 440 and may instruct the chiller system 446 to output chilled working fluid 496 at a temperature above the dew point temperature of the return air 440. That is, the controller 500 may instruct the chiller system 446 to output chilled working fluid 496 at a temperature that is above the dew point temperature of the return air 440 by a threshold value and/or by a threshold percentage, for example. In certain embodiments, the controller 500 may adjust a flow rate of the chilled working fluid 496 output by the chiller system 446 such that a temperature of the chilled working fluid 496 arriving at the second heat exchanger 434 is above the dew point temperature of the return air 440.
In some embodiments, a temperature of the ventilation air 408 received from the air handling unit 402 may be substantially equal to or less than the target temperature setpoint for the room 442. In such embodiments, the ventilation air 408 output by the air handling unit 402 may be sufficient to satisfy the cooling demand of the room 442, such that the controller 500 may stay (e.g., temporality block) operation of the chiller system 446. That is, the controller 500 may operate the second blower 432 to draw the return air 440 across the second heat exchanger 434, while the second heat exchanger 434 is in an inactive state, to mix the return air 440 with the ventilation air 408 entering the terminal unit 404.
In some embodiments, the terminal unit 404 may include one or more dampers 550 (e.g., control mechanisms, flow control devices, variable air volume [VAV] devices) that may enable the return air 440 to bypass the second heat exchanger 434 (e.g., during operational periods in which the second heat exchanger 434 is inactive) and enter the interior of the terminal unit 404. For example, the controller 500 may be configured to instruct the dampers 550 to transition to an open configuration while the second heat exchanger 434 is inactive (e.g., not circulating chilled working fluid 496), such that the second blower 432 may draw the return air 440 into the terminal unit 404 and mix the return air 440 with the ventilation air 408 without directing the return air 440 across the second heat exchanger 434. Conversely, during operational periods in which the second heat exchanger 434 is active (e.g., circulating the chilled working fluid 496), the controller 500 may instruct the dampers 550 to close such that the second blower 432 may draw the return air 440 across the second heat exchanger 434. In some embodiments, the one or more dampers 550 may be configured to control a flow rate of the ventilation air 408 from the first ductwork 406 into the terminal unit 404 and/or control a flow rate of the supply air 450 discharged from the terminal unit 404 into the second ductwork 456.
The DV diffuser 454 may include the outlet 458 configured to discharge the supply air 450 along the floor 520 of the room 442. A cross-sectional area of the outlet 458 may be relatively large, such that a discharge velocity of the supply air 450 from the DV diffuser 454 is relatively low. In this manner, the DV diffuser 454 may disperse the supply air 450 (e.g., cooled air) along the floor 520 without substantially generating turbulent airflow throughout other portions of the room 442. That is, the DV diffuser 454 may facilitate supply of fresh supply air 450 (e.g., filtered air, conditioned outdoor air 422) to the room 442 while avoiding turbulent interaction between the supply air 450 and stale or existing air in the room 442. As the supply air 450 in the room 442 is gradually heated (e.g., via interaction with the floor 520, with human occupants within the room 442, with other heat sources), the supply air 450 may rise from the floor 520 toward a ceiling 552 of the room 442. The exhaust duct 510 may be positioned near the ceiling 552 and be configured to discharge the heated supply air 450 from the room as exhaust air 512.
In some embodiments, the third enclosure 452 (e.g., housing) of the DV diffuser 454 may define a plenum of the DV diffuser 454, which may be fluidly coupled to the second ductwork 456. A grille 556 may be removably coupled to the third enclosure 452 and be configured to position or retain the filter 459 across the outlet 458 of the DV diffuser 454. That is, the grille 556 may be configured to removably couple the filter 459 to the third enclosure 452. In some embodiments, the grille 556 may be removeable by an occupant within the room 442 to provide the occupant with access to the filter 459. Accordingly, the occupant may remove the filter 459 for cleaning and/or replacement with a new filter. In certain embodiments, the filter 459 may be sealed or otherwise secured to the third enclosure 452 via a continuous frame (e.g., knife edge frame) that may be formed on the third enclosure 452. Further, a seal (e.g., a gelatinous solution) may be placed between the third enclosure 452 and the filter 459 to mitigate or substantially block air flow between the third enclosure 452 and the filter 459.
In some embodiments, the third enclosure 452 may include a first panel 560 or wall, a second panel 562 or wall, an upper panel 564 or wall, and a lower panel or wall that, together with the grille 556, may bound an interior region of the third enclosure 452. The first panel 560 and the second panel 562 may converge at a vertex 568 that may be configured to align with a corner 570 of the room 442 (e.g., an intersection of walls of the room 442). As such, the DV diffuser 454 may be positioned within the corner 570 in a space efficient manner and be configured to output supply air 450 to the room 442 outwardly from the corner 570 and toward a central region of the room 442. The grille 556 may be configured to extend across the outlet 458 from the first panel 560 to the second panel 562. As such, the grille 556, the first panel 560, and the second panel 562 may bound an interior region (e.g., a plenum) of the third enclosure 452.
FIG. 6 is a cross-sectional side view of an embodiment of the DV diffuser 454. In the illustrated embodiment, the DV diffuser 454 includes the third enclosure 452, the grille 556, and the filter 459 positioned between the third enclosure 452 and the grille 556. As discussed above, the third enclosure 452 and the grille 556 may collectively bound an interior region or plenum 571 of the DV diffuser 454. The plenum 571 may be fluidly coupled to an inlet 572 of the third enclosure 452, which may be configured to couple to the first ductwork 406 and receive the supply air 450.
In some embodiments, the grille 556 (e.g., a cover face) may be detachable (e.g., fully removeable) from the third enclosure 452 to enable user access to the filter 459 extending across the outlet 458 of the DV diffuser 454. In certain embodiments, the grille 556 may be pivotably and/or angularly displaceable relative to the third enclosure 452 to enable user access to the filter 459. In some embodiments, the grille 556 may be configured to house (e.g., couple to) the filter 459 and/or may include a diffuser face that is perforated.
As set forth above, embodiments of the present disclosure may provide one or more technical effects useful for facilitating conditioning of spaces serviced by an HVAC system while mitigating or substantially eliminating mixing (e.g., turbulent mixing) of air supplied to the space with existing air in each of the spaces, and while mitigating or substantially eliminating exchange of air between the different spaces. As such, the improved HVAC system disclosed herein may mitigate or substantially eliminate exchange of air between individual rooms, zones, or other spaces serviced by the HVAC system to substantially inhibit transmission of airborne contaminants between the individual spaces, while still providing conditioning to each of the spaces.
It should be understood that the technical effects and technical problems in the specification are examples and are not limiting. Indeed, it should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.
While only certain features and embodiments of the present disclosure have been illustrated and described, many modifications and changes may occur to those skilled in the art, such as variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, such as temperatures and pressures, mounting arrangements, use of materials, colors, orientations, and so forth, without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the present disclosure. Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described, such as those unrelated to the presently contemplated best mode of carrying out the present disclosure, or those unrelated to enabling the claimed embodiments. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.
The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Claims

1. A heating, ventilation, and/or air conditioning (HVAC) system, comprising:

an air handling unit configured to condition an outdoor air flow to generate a ventilation air flow;

a terminal unit fluidly coupled to the air handling unit and comprising:

a plenum configured to receive the ventilation air flow; and

a blower configured to draw a return air flow from a space serviced by the HVAC system across a heat exchanger of the terminal unit and into the plenum to condition the return air flow, wherein the blower is configured to mix the ventilation air flow and the return air flow to generate a supply air flow; and

a displacement ventilation (DV) diffuser fluidly coupled to the terminal unit and configured to receive the supply air flow, wherein the DV diffuser is configured to receive a filter configured to filter the supply air flow, and wherein the DV diffuser is configured to direct the supply air flow through the filter and into the space.

2. The HVAC system of claim 1, comprising the filter, wherein the filter comprises a high efficiency particulate air (HEPA) filter configured to capture particles having a size between 1.0 micron and 3.0 microns in diameter.

3. The HVAC system of claim 1, wherein the heat exchanger is configured to circulate a working fluid at a temperature above a first dew point temperature of the return air flow to cool the return air flow without dehumidifying the return air flow.

4. The HVAC system of claim 3, wherein the air handling unit comprises an additional heat exchanger configured to operate below a second dew point temperature of the outdoor air flow to cool and dehumidify the outdoor air flow.

5. The HVAC system of claim 3, comprising:

one or more sensors configured to acquire feedback indicative of a temperature of the return air flow, a humidity of the return air flow, or both; and

a controller communicatively coupled to the one or more sensors and configured to receive the feedback, wherein the controller is configured to determine the first dew point temperature based on the temperature of the return air flow, the humidity of the return air flow, or both.

6. The HVAC system of claim 5, comprising a chiller system configured to provide the working fluid to the heat exchanger, wherein the controller is configured to control the chiller system to maintain the temperature of the working fluid above the first dew point temperature.

7. The HVAC system of claim 1, wherein the terminal unit comprises an additional filter, and wherein the blower is configured to draw the return air flow across the additional filter.

8. The HVAC system of claim 7, wherein the additional filter comprises a HEPA filter, a MERV-6 filter, or a MERV-8 filter.

9. The HVAC system of claim 1, wherein the terminal unit comprises a reheat coil configured to receive the supply air flow and heat the supply air flow.

10. The HVAC system of claim 1, comprising:

a ventilation duct fluidly coupling the air handling unit and the terminal unit;

an exhaust duct fluidly coupled to the space and to an outdoor environment; and

an exhaust blower configured to draw an exhaust air flow from the space and discharge the exhaust air flow to the outdoor environment via the exhaust duct, wherein the air handling unit, the ventilation duct, and the terminal unit do not receive a portion of the exhaust air flow from the exhaust duct.

11. The HVAC system of claim 1, wherein the terminal unit is configured to be positioned adjacent to a ceiling of the space and the DV diffuser is configured to be positioned adjacent to a floor of the space.

12. A displacement ventilation (DV) diffuser, comprising:

an enclosure comprising an inlet configured to receive an air flow and an outlet configured to discharge the air flow, wherein the enclosure is configured to receive a high efficiency particulate air (HEPA) filter such that the HEPA filter extends across the outlet and is configured to filter the air flow; and

a grille removeably coupled to the enclosure and configured to secure the HEPA filter to the enclosure.

13. The DV diffuser of claim 12, comprising the HEPA filter, wherein the HEPA filter is configured to capture particles in the air flow having a size between 1.0 micron and 3.0 microns in diameter.

14. The DV diffuser of claim 12, wherein the enclosure comprises a first wall and a second wall, wherein the first wall and the second wall converge at a vertex of the enclosure, and wherein the grille is configured to extend from the first wall to the second wall.

15. A heating, ventilation, and/or air conditioning (HVAC) system, comprising:

an air handling unit comprising a first heat exchanger configured to dehumidify an outdoor air flow to generate a ventilation air flow;

a terminal unit configured to receive the ventilation air flow and comprising:

a second heat exchanger configured to circulate a working fluid; and

a blower configured to draw a return air flow across the second heat exchanger to condition the return air flow and to mix the return air flow with the ventilation air flow to generate a supply air flow; and

a displacement ventilation (DV) diffuser configured to receive the supply air flow and comprising a filter configured to filter the supply air flow, wherein the filter comprises a high efficiency particulate air (HEPA) filter.

16. The HVAC system of claim 15, comprising:

a chiller system configured to supply the working fluid to the second heat exchanger; and

a controller configured to determine a dew point temperature of the return air flow based on feedback from a sensor exposed to the return air flow, wherein the controller is configured to adjust the chiller system to maintain a temperature of the working fluid above the dew point temperature of the return air flow.

17. The HVAC system of claim 15, wherein the terminal unit is disposed within a space serviced by the HVAC system, and the DV diffuser is configured to discharge the supply air flow along a floor of the space serviced by the HVAC system.

18. The HVAC system of claim 15, comprising:

an exhaust duct fluidly coupled to an outdoor environment and to a space serviced by the DV diffuser; and

an exhaust blower configured to draw an exhaust air flow from the space and discharge the exhaust air flow to the outdoor environment via the exhaust duct, wherein the air handling unit and the terminal unit do not receive a portion of the exhaust air flow from the exhaust duct.

19. The HVAC system of claim 15, wherein the terminal unit comprises an additional filter, wherein the blower is configured to draw the return air flow across the additional filter and the second heat exchanger.

20. The HVAC system of claim 19, wherein the terminal unit is configured to provide access to the additional filter from a space serviced by the DV diffuser, such that the additional filter is replaceable by an occupant located within the space.