CROSS REFERENCE TO RELATED APPLICATIONThis application claims the benefit of U.S. Provisional Application Ser. No. 61/754,936, filed by Pete Hrejsa, et al., on Jan. 21, 2013, entitled “METHOD FOR OBTAINING DEMAND SPECIFIC DATA FROM A REMOTE UNIT,” which is currently pending and incorporated herein by reference.
TECHNICAL FIELDThis application is directed, in general, to heating, ventilating and air conditioning (HVAC) systems and, more specifically, to demand data for HVAC systems.
BACKGROUNDHVAC systems can be used to regulate the environment within an enclosure. Typically, a thermostat call initiates operation of an HVAC system that results in a circulating fan pulling air from the enclosure into the HVAC system through ducts and pushing the air back into the enclosure through additional ducts after conditioning the air (e.g., heating or cooling the air). Some circulating fans move air through the HVAC system at different volumes that can vary based on the operating mode (e.g., heating, cooling, dehumidification) of the HVAC system and the requested compressor capacity or speed per the thermostat call.
SUMMARYIn one aspect, a controller for a multispeed outdoor unit of a HVAC system is disclosed. In one embodiment, the outdoor unit controller includes: (1) an interface configured to receive a request for a second portion of demand data from an indoor controller of the HVAC system, wherein the request includes a first portion of the demand data that corresponds to the second portion and (2) a processor configured to respond to the request by determining the second portion based on the first portion and sending the second portion of the demand data to the indoor controller of the HVAC system.
In another aspect, a controller for an indoor unit of a HVAC system is disclosed. In one embodiment, the indoor unit controller includes: (1) an interface configured to receive a thermostat call and (2) a processor configured to send a request for demand data that corresponds to the thermostat call to a controller of an outdoor unit of the HVAC system, wherein the requested demand data is a blower volume for a circulating fan of the HVAC system.
In still yet another aspect, a multispeed outdoor unit of a HVAC system is provided. In one embodiment, the multispeed outdoor unit includes: (1) a compressor and (2) an outdoor unit controller configured to direct operations of the compressor, the outdoor unit controller including (2A) an interface configured to receive a request for a second portion of demand data from an indoor controller of the HVAC system, wherein the request includes a first portion of the demand data that corresponds to the second portion and (2B) a processor configured to respond to the request by determining the second portion based on the first portion and sending the second portion of the demand data to the indoor controller of the HVAC system.
BRIEF DESCRIPTIONReference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 illustrates a high-level block diagram of an embodiment of a HVAC system constructed according to the principles of the disclosure;
FIG. 2 illustrates a block diagram of an embodiment of an outdoor unit controller of an HVAC system constructed according to the principles of the disclosure;
FIG. 3 illustrates a block diagram of an embodiment of an indoor unit controller of an HVAC system constructed according to the principles of the disclosure;
FIG. 4 illustrates a flow diagram of an embodiment of a method of operating an HVAC system carried out according to the principles of the disclosure; and
FIG. 5 illustrates a flow diagram of an embodiment of another method of operating an HVAC system carried out according to the principles of the disclosure.
DETAILED DESCRIPTIONThe blower volumes for a circulating fan are usually stored in an indoor controller of a HVAC system. The blower volume is the airflow capacity (often expressed in terms of cubic feet per minute, or CFM) of the circulating fan. Typically, storing the blower volume in a controller of the indoor unit has been convenient since the blower volume for a compressor speed is fairly constant and universal for different types of compressors. In some HVAC systems, modulating compressor is used that operates more efficiently compared to conventional single stage units and reduces energy costs.
When operating the modulating compressor there are often specific blower volumes that correspond to each compressor speed. The relationship between blower volume and compressor speed is non-linear and unique for each type of compressor. As such, maintaining the blower volume for each compressor capacity of every thermostat call can require a large portion of memory for an indoor controller of an HVAC system. Additionally, upgrading the indoor controller with new blower volumes for compressor speed data can be cumbersome.
Accordingly, the disclosure provides a system and scheme that does not require a HVAC indoor controller to store the desired blower volumes to deliver for operating speeds of an outdoor unit. Instead, the disclosed HVAC system stores the demand blower volumes in the outdoor unit and requests the specific blower volume from the outdoor unit for a particular operating speed. An outdoor unit controller can be used to store the corresponding operating compressor speeds and blower volumes. The values for each can be stored in a data table in a memory of the outside unit controller. In one embodiment, a look-up table is used.
Thus, the embodiments disclosed herein relieve the indoor controller from the burden of knowing each outdoor unit's blower volume to demand relationship. Additionally, the embodiments allow an existing indoor unit to be compatible with new outdoor units of the HVAC system. The new outdoor units can even be currently undeveloped outdoor units.
In addition to modulating compressors, some HVAC systems also use zone controls. A zone controlled system allows a user to independently control the temperature in various designated zones of an enclosure, such as a house. A zone control panel or zone controller manages the movement of conditioned air to the various zones using electronic dampers and thermostats dedicated to each of the zones. Harmony III™ Zone Control System available from Lennox Industries, Inc. of Richardson, Tex., is an example of a zoning system that manages the distribution of conditioned air to designated zones.
In a zone controlled system, a zone controller generates a blower control signal to control the operating speed of a circulation fan. As such, the blower control signal is used to control the blower volume of the circulation fan. The blower control signal typically changes in a zone controlled system when demand changes to different or more zones. For example, a thermostat in a first zone may demand heat. As such, the furnace initiates and provides heat for the first zone based on the heating call and an operating speed for the circulation fan for the first zone. A thermostat for a second zone then demands heat. Accordingly, the furnace continues to provide heat with an operating speed of the circulation fan based on the blower control signal generated by the zone controller for both the first and second zones. The blower control signal is typically an electrical signal generated by a zoning control panel in response to thermostat demands from different zones. The blower control signal can be an analog or a digital signal. Considering the Harmony III™ Zone Control System, a pulse width modulated (PWM) signal is used for a blower control signal and a change in the duty cycle of the PWM signal indicates a change in the operating speed of the circulation fan. In other embodiments, the blower control signal can be a data signal including a messaging protocol signal, such as a controller area network (CAN) signal, or an output of a transducer.
In these embodiments, the blower volume is known from the blower control signal and does not need to be requested by the indoor unit controller from the outdoor unit controller. Instead, the indoor unit controller can send the known blower volume to the outdoor unit controller that can determine the corresponding operating speed of the outdoor unit. The outdoor unit controller can then send the demand level, or percent demand of the outdoor unit that corresponds to the blower volume, back to the indoor unit controller so that it knows the level of demand to send. Thus, known data from the indoor unit controller can be used by the outdoor unit controller to determine either portion of the demand data not known.
FIG. 1 is a high-level block diagram of an embodiment of aHVAC system100 constructed according to the principles of the disclosure. In one embodiment, theHVAC system100 is configured to provide ventilation and therefore includes one ormore circulation fans110. In an alternative embodiment, the ventilation includes one ormore dampers115 to control air flow through air ducts (not shown.) Such control may be used in various embodiments in which theHVAC system100 is a zoned system. In the context of a zonedHVAC system100, the one ormore dampers115 may be referred to aszone controllers115.
Thezone controller115 is configured to manage conditioned air for designated zones of a conditioned space. A zone is a portion of a HVAC system that includes at least one demand unit, such as thefurnace120, and includes at least one user interface, such as a thermostat. Thezone controller115 operates electronic dampers to control air flow to zones of the conditioned space. Thezone controller115 generates a blower control signal to request a blower volume for thecirculation fan110. In some embodiments, thezone controller115 is configured to provide greater air flow to different zones to compensate for greater heating load or air flow requirements. As such, the blower control signal requests a greater blower volume with respect to, for example, a heating call for a first zone than a second zone. Thezone controller115 can be a conventional controller for delivering conditioned air to designated zones of a conditioned space. For example, the zone controller190 can be a Harmony III™ Zone Controller.
In some embodiments, theHVAC system100 is configured to provide heating and therefore includes one ormore furnaces120, typically associated with the one ormore circulation fans110. In an alternative embodiment, theHVAC system100 is configured to provide cooling and therefore includes one or more refrigerant evaporator coils130, typically associated with the one ormore circulation fans110. Such embodiment of theHVAC system100 also includes one ormore compressors140 and associated condenser coils142, which are typically associated in one or more so-called “outdoor units”144. The one ormore compressors140 and associated condenser coils142 are typically connected to an associatedevaporator coil130 by arefrigerant line146.
Although not shown inFIG. 1, theHVAC system100 may include one or more heat pumps in lieu of or in addition to the one ormore furnaces120, and one ormore compressors140. One or more humidifiers or dehumidifiers may be employed to increase or decrease humidity.
TheHVAC system100 can be configured to provide ventilation, heating and cooling, wherein the one ormore circulation fans110,furnaces120 andevaporator coils130 are associated with one or more “indoor units”148, e.g., basement or attic units.
One or moreindoor unit controllers150 control one or more of the one ormore circulation fans110, the one ormore furnaces120 and/or the one ormore compressors140 to regulate the temperature of the premises, at least approximately. Theindoor unit controller150 may be an integrated controller or a distributed controller that directs operation of theHVAC system100. Theindoor unit controller150 may include an interface to receive thermostat calls and a blower control signal, and a processor, such as a microprocessor, to direct the operation of theHVAC system100. Theindoor unit controller150 may include a memory section having a series of operating instructions stored therein that direct the operation of the indoor unit controller150 (e.g., the processor) when initiated thereby. The series of operating instructions may represent algorithms that are used to obtain blower volumes for thecirculation fans110 and operating speeds of thecompressors140. For example, the algorithms can implement the method illustrated inFIG. 4. Theindoor unit controller150 can be a central HVAC controller or a thermostat. A thermostat can generate thermostat calls based on temperature settings. The thermostat calls include, for example, heating calls, cooling calls and dehumidifying calls.
In various embodiments, the one ormore displays170 provide additional functions such as operational, diagnostic and status message display and an attractive, visual interface that allows an installer, user or repairman to perform actions with respect to theHVAC system100 more intuitively. Herein, the term “operator” will be used to refer collectively to any of the installer, the user and the repairman unless clarity is served by greater specificity. Thedisplays170 can be part of theindoor unit controllers150.
One or moreseparate comfort sensors160 may be associated with the one or moreindoor unit controller150 and may also optionally be associated with one ormore displays170. The one ormore comfort sensors160 provide environmental data, e.g. temperature and/or humidity, to the one or moreindoor control units150. Anindividual comfort sensor160 may be physically located within a same enclosure or housing as thecontrol unit150. In such cases, the commonly housedcomfort sensor160 may be addressed independently. However, the one ormore comfort sensors160 may be located separately and physically remote from the one or moreindoor control units150. Also, anindividual control unit150 may be physically located within a same enclosure or housing as adisplay170. In such embodiments, the commonly housedcontrol unit150 anddisplay170 may each be addressed independently. However, one or more of thedisplays170 may be located within theHVAC system100 separately from and/or physically remote to theindoor control units150. The one ormore displays170 may include a screen such as a liquid crystal display (not shown).
Adata bus180, which in the illustrated embodiment is a serial bus, couples the one ormore circulation fans110, the one ormore furnaces120, the one or moreevaporator coils130, the one or more condenser coils142 andcompressors140, the one or moreindoor control units150, the one or moreremote comfort sensors160 and the one ormore displays170 such that data may be communicated therebetween or thereamong. As will be understood, thedata bus180 may be advantageously employed to convey one or more alarm messages or one or more diagnostic messages. A conventional cable and contacts may be used to couple theindoor unit controller150 to the various components. In some embodiments, a wireless connection may also be employed to provide at least some of the connections. Thedata bus180 can also be a wired-connection.
At least one of thecirculation fans110 operates at different capacities, i.e., motor speeds, to circulate air through theHVAC system100, whereby the circulated air is conditioned and supplied to the conditioned space. The circulating fan moves the air at a certain capacity according to the blower volume. Different blower volumes correspond to various operating speeds of thecompressor140. Thecompressor140 operates within a range from a minimum to a maximum capacity and the operating speed of the compressor is denoted as a percentage of the maximum operating capacity. The relationship between the blower volumes and the operating speeds is represented by a non-linear curve. In some embodiments, the relationships between operating speeds of thecompressor140 and the blower volumes of the circulating fan are stored in a memory of theoutdoor unit controller148. In one embodiment, the related blower volumes and operating speeds are stored in a data table in the memory. The data table can include entries for the values on the curve at 1% intervals of the operating capacity of thecompressor140. The number of entries in the data table is based on a balance between storage space and look-up speed. Theoutdoor unit controller148 is configured to interpolate a requested demand data value if there are no corresponding entries in the table. For example, theindoor unit controller150 can receive a thermostat call with a percent demand (operating speed) of 21.5%. If the data table includes entries at one percent (1%) increments between the minimum and maximum operating capacity and includes entries at 21% and 22%, then theoutdoor unit controller148 interpolates between the corresponding blower volume values for the 21% and 22% operating capacities of thecompressor140. Theoutdoor unit controller148 can then send the interpolated blower volume value to theindoor unit controller150.
FIG. 2 illustrates a block diagram of an embodiment of anoutdoor unit controller200 constructed according to the principles of the disclosure. Theoutdoor unit controller200 is configured to direct the operation of an outdoor unit of a HVAC system. Additionally, theoutdoor unit controller200 is configured to determine a blower volume that corresponds to an operating speed of the outdoor unit. In some embodiments, theoutdoor unit controller200 is also configured to determine an operating speed based on a received blower volume. As such, theoutdoor unit controller200 is configured to generate control signals that are transmitted to an indoor unit controller of the HVAC system to employ in directing the operation of the HVAC system. Theoutdoor unit controller200 can generate a reply to the indoor unit controller that includes the needed demand data, i.e., blower volumes or operating speeds, which was asked for in a request from the indoor unit controller.
Theoutdoor unit controller200 includes aninterface210 that is configured to receive and transmit the demand data to the indoor unit controller. Theinterface210 may be a conventional interface that is used to communicate (i.e., receive and transmit) data for a controller, such as a microcontroller.
Theoutdoor unit controller200 also includes aprocessor220 and amemory230. Thememory230 may be a conventional memory typically located within a controller, such as a microcontroller, that is constructed to store data and computer programs. Thememory230 may store operating instructions to direct the operation of theprocessor220 when initiated thereby. The operating instructions may correspond to algorithms that provide the functionality of the operating schemes disclosed herein. For example, the operating instructions may correspond to the algorithm or algorithms that implement the method illustrated inFIG. 4. Theprocessor220 may be a conventional processor such as a microprocessor. Theinterface210,processor220 andmemory230 may be coupled together via conventional means to communicate information. Theoutdoor unit controller200 may also include additional components typically included within a controller for an outdoor unit, such as a power supply or power port. The outdoor unit can be a compressor for cooling or for heating.
Thememory220 is configured to store demand data for the HVAC system. The demand data includes operating speeds of the outdoor unit and blower volumes that correspond to the operating speeds. In one embodiment, the stored blower volumes correspond to blower volumes represented by blower control signals. The stored blower volumes and operating speeds correspond to a non-linear curve that represents the relationship therebetween. The stored values can be pre-programmed in thememory220 during manufacturing or installation and can be based on the model or type of outdoor unit. A table or tables, such as a look-up table, may store the various demand data.
Theprocessor230 is configured to operate the outdoor unit at an operating speed received from the indoor unit controller. Theprocessor230 is also configured to employ the received operating speed to look-up the corresponding blower volume from thememory220. Theprocessor230 is also configured to transmit the determined blower volume to the indoor unit controller.
In some embodiments, theoutdoor unit controller200 does not receive an operating speed from the indoor unit controller but instead receives a blower volume. As such, theprocessor230 is configured to determine the proper operating speed from the look-up table employing the blower volume. If needed, theprocessor230 can interpolate the operating speed from the look-up table. Whether received or determined, theprocessor230 directs the operation of the compressor based on control signals that correspond to the operating speed. In one embodiment, theprocessor230 is configured to operate according to the method illustrated inFIG. 4.
FIG. 3 illustrates a block diagram of an embodiment of anindoor unit controller300 of an HVAC system constructed according to the principles of the disclosure. Theindoor unit controller300 is configured to direct the operation of or at least part of the operation of the HVAC system, such as theHVAC system100. As such, theindoor unit controller300 is configured to generate control signals that are transmitted to the various components to direct the operation thereof. Theindoor unit controller300 may generate the control signals in response to feedback data and/or operating data that is received from various sensors and/or components of the HVAC system. For example,indoor unit controller300 can generate a control signal to operate a circulating fan of the HVAC system. Theindoor unit controller300 includes aninterface310 that is configured to receive and transmit the feedback data, operating data, control signals and demand data. The operating data received by theinterface310 includes a blower control signal and a thermostat call. Theinterface310 may be a conventional interface that is used to communicate (i.e., receive and transmit) data for a controller, such as a microcontroller.
Theindoor unit controller300 also includes aprocessor320 and amemory330. Thememory330 may be a conventional memory typically located within a controller, such as a microcontroller, that is constructed to store data and computer programs. Thememory330 may store operating instructions to direct the operation of theprocessor320 when initiated thereby. The operating instructions may correspond to algorithms that provide the functionality of at least some of the operating schemes disclosed herein. For example, the operating instructions may correspond to the algorithm or algorithms that implement the method illustrated inFIG. 5. Theprocessor320 may be a conventional processor such as a microprocessor. Theinterface310,processor320 andmemory330 may be coupled together via conventional means to communicate information. Theindoor unit controller300 may also include additional components typically included within a controller for a furnace, such as a power supply or power port.
Thememory320 is configured to store operating instructions for the HVAC system. Unlike conventional indoor unit controllers, thememory320 does not include operating speeds for an outdoor unit of the HVAC system and the corresponding blower volumes for a circulating fan of the HVAC system.
Theprocessor330 is configured to operate the HVAC system according to the feedback data, operating data and demand data to provide conditioned air in response to the received thermostat calls and, in some embodiments, the blower control signal. In one embodiment, theprocessor330 is configured to operate the HVAC system according to the method illustrated inFIG. 5.
FIG. 4 illustrates a flow diagram of an embodiment of amethod400 of operating a HVAC system carried out according to the principles of the disclosure. Theoutdoor unit controller148 ofFIG. 1 or theoutdoor unit controller200 ofFIG. 2 may be used to perform themethod400. Themethod400 includes determining the blower volume for a circulating fan of the HVAC system. Themethod400 begins in astep405.
In astep410, a blower volume request is received. The blower volume request can be generated by an indoor unit controller in response to a thermostat call. The blower volume request includes a mode of operation and the percent demand (operating speed) needed by the outdoor unit according to a thermostat call. The mode of operation includes, for example, cooling normal, cooling comfort, cooling efficiency, heating mode, etc.
An operating mode of the outdoor unit is set in astep410. The operating mode is set based on the received blower volume request. The outdoor unit remains in the set mode until receiving another blower volume request message that sets a different operating mode. In some embodiments, the outdoor unit remains in the set operating mode until receiving a demand that does not match the current operating mode. For example, a heating demand is received when the current operating mode that is set is a cooling demand.
In astep430, a blower volume is determined in response to the blower volume request. In one embodiment, the blower volume is determined from a look-up table employing the percent demand from the blower volume request. In some embodiments, the blower volume is calculated by interpolating between values of the look-up table.
In astep440, a response to the blower volume request is generated. The response, referred to in some embodiments as the blower volume response, is a message that includes the requested mode and the blower volume required of the indoor unit for the percent demand sent in the blower volume request. A reply to the blower volume request is sent in astep450 that includes the response. In one embodiment, the reply is sent from the outdoor unit controller to the indoor unit controller of the HVAC system. Themethod400 ends in astep460.
FIG. 5 illustrates a flow diagram of an embodiment of amethod400 of operating a HVAC system carried out according to the principles of the disclosure. Theindoor unit controller150 ofFIG. 1 or theindoor unit controller300 ofFIG. 3 may be used to perform themethod300. Themethod500 includes determining demand data for the HVAC system. Themethod300 begins in astep505.
In astep510, a thermostat call is received. The thermostat call can be a conventional request for heating or cooling demands of the HVAC system. The thermostat can be associated with a zone controller of the HVAC system.
In astep520, a blower volume request is generated. The blower volume request is generated in response to the thermostat call. For system demands, such as heating and cooling demands, the indoor unit operates its circulation fan at the blower volume required by the outdoor unit. As such, an indoor unit controller can generate the blower volume request. The blower volume request includes the percent demand needed by the outdoor unit and the operating mode of operation.
In astep530, a reply to the blower volume request is received. The reply includes the requested mode of operation and the blower volume required of the indoor unit for the percent demand sent in the blower volume request. The reply can be sent by the outdoor unit controller of the HVAC system.
The circulation fan of the HVAC system is operated according to the received blower volume in astep540. In one embodiment, the indoor unit controller of the HVAC system generates control signals to direct the operation of the circulation fan according to the received blower volume. Themethod500 ends in astep550.
The above-described methods may be embodied in or performed by various conventional digital data processors, microprocessors or computing devices, wherein these devices are programmed or store executable programs of sequences of software instructions to perform one or more of the steps of the methods, e.g., steps of the method ofFIG. 4 orFIG. 5. The software instructions of such programs may be encoded in machine-executable form on conventional digital data storage media that is non-transitory, e.g., magnetic or optical disks, random-access memory (RAM), magnetic hard disks, flash memories, and/or read-only memory (ROM), to enable various types of digital data processors or computing devices to perform one, multiple or all of the steps of one or more of the above-described methods, e.g., one or more of the steps of the method ofFIG. 4 orFIG. 5. Additionally, an apparatus, such as indoor unit controller or an outdoor unit controller, may be designed to include the necessary circuitry or programming to perform each step of a method of disclosed herein.
Portions of disclosed embodiments may relate to computer storage products with a non-transitory computer-readable medium that have program code thereon for performing various computer-implemented operations that embody a part of an apparatus, system, carry out the steps of a method set forth herein or provide a single user interface screen as disclosed. Non-transitory used herein refers to all computer-readable media except for transitory, propagating signals. Examples of non-transitory computer-readable media include, but are not limited to: magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD-ROM disks; magneto-optical media such as floptical disks; and hardware devices that are specially configured to store and execute program code, such as ROM and RAM devices. Examples of program code include both machine code, such as produced by a compiler, and files containing higher level code that may be executed by the computer using an interpreter.
Those skilled in the art to which this application relates will appreciate that other and further additions, deletions, substitutions and modifications may be made to the described embodiments.