HVAC communication and control system and method

Abstract

A system and method of communication and control for heating, ventilation, and air conditioning (HVAC) systems is disclosed, which allows for semi-continuous communication and control with multiple HVAC systems, that will not be interrupted by a breakdown in any one particular HVAC system, and that allows the graceful addition and upgrade of new command and control structure with non-compliance by connected individual HVAC systems.

Description

HVAC COMMUNICATION AND CONTROL SYSTEM AND METHODFIELD OF THE INVENTION

[0001] The present invention generally relates to a communication and control system for Heating, Ventilation and Air Conditioning (“HVAC”) systems.BACKGROUND OF THE INVENTION

[0002] HVAC systems affect and ideally control environmental conditions in an area, such as temperature, humidity, and airflow. In modern buildings, there may be multiple HVAC systems in a given living area, potentially allowing, for example, for different rooms in a house or condominium or laboratory or industrial space to be kept at different temperatures or humidity.

[0003] An HVAC system itself can consist of many components, such as air handlers (e.g. fans), condensers, evaporators, furnaces, boilders or chillers. Each of these in turn can have a controller associated with the component and also can have various sensors that either are used to control the component, or report on the component’s functioning. While these can be as simple as a bang-bang thermostat (that turns a heating system on when the temperature drops below a certain setpoint and turns the heating system off when the temperature rises above a certain setpoint), controllers can be more sophisticated.

[0004] Previous approaches to communication with and / or operating HVAC systems are known. US11 ,624,522 of Jones discloses a maintenance system including an indoor unit and an outdoor unit, a communications line extending between them, and a probe that reads operational data off the communications line and sends the operations data to a remote server, where it is analyzed and used to direct maintenance requests. US11 ,644, 209 of Castillo et al. discloses a control unit communicatively coupled to a plurality of HVAC units and a plurality of sensors using a Wi-FI direct protocol, and whichis connected via direct Wi-Fi protocol to a second control unit which has wireless Wi-Fi communications, and then switching communications with the HVAC units and sensors to wireless communication via the second control unit. US9,865,983 of Schultz et al. discloses a portable wireless device that allows a user to control a thermostat remotely based on either the temperature measured by the portable wireless device or the temperature sensor of the thermostat. US10,935,271 of Reeve et al. discloses a method of controlling an HVAC system which includes using the temperature indoors compared to the outdoor temperature as predicted using weather data to determine trends in HVAC capacity availability. Finally, US10,845,076 of Blair et al. discloses a method of monitoring an HVAC component via a dedicated diagnostic data bus.SUMMARY OF THE INVENTION

[0005] This invention is focused on smart buildings or smart communities, where multiple systems such as multiple HVAC systems need to be elegantly coordinated and controlled from a centralized control system. In particular, this HVAC communication and control system allows for semi-continuous communication and control with multiple HVAC systems, that will not be interrupted by a breakdown in any one particular HVAC system, and that allows the graceful addition and upgrade of new command and control structure with non-compliance by connected individual HVAC systems.

[0006] In accord with the invention, there is provided an HVAC control and communication system, comprising: a communication and control module connected to a first HVAC controller by a communication hub, where the communication and control module is configured to send a first command request to the first HVAC controller, where the first command request is an eight-byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte first command, and the first HVAC controller is configured to send a first command acknowledgement to the communication and control module, where the first command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments,each segment containing information about the state of a first HVAC system controlled by the first HVAC controller.

[0007] In an aspect of the invention, the communication and control module is configured to send a second command request to the first HVAC controller, where the second command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte second command, and the first HVAC controller is configured to send a second command acknowledgement to the communication and control module, where the second command acknowledgement is an eight byte structure comprising a one-byte second acknowledgement identifier and a second set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller.

[0008] In another aspect of the invention, the communication and control module controller is configured to send a third command request to the first HVAC controller, where the third command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte third command to change the settings of the first HVAC system, and the first HVAC controller is configured to send a third command acknowledgement to the communication and control module, where the third command acknowledgement is an eight byte structure comprising a third acknowledgement identifier and a third set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller, and at least one of the third set of six one-byte information segments of the third command acknowledgement confirming the change of the settings of the first HVAC system.

[0009] In still another aspect of the invention, the communication and control module controller is configured to send a fourth command request to the first HVAC controller, where the fourth command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte fourth command to change the settings of the first HVAC system.

[0010] In another aspect of the invention, there is provided a second HVAC controller that controls a second HVAC system, the second HVAC controller being connected to the communication and control module by the communication hub.

[0011] In still another aspect of the invention, the first HVAC controller and the second HVAC controller are connected in parallel to the communication and control module.

[0012] In another aspect of the invention, the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at a 9600 baud rate. In still another aspect of the invention, the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at rate of at least 9600 baud.

[0013] In accord with the invention, there is provided an HVAC control system comprising: a communication and control module connected to a first HVAC controller by a communication hub, where the communication and control module is configured to send one of a first set of command requests to the first HVAC controller, where each command request is an eight-byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte first command, and the first HVAC controller is configured to send one of a first set of command acknowledgements to the communication and control module, where each command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containing information about the state of a first HVAC system controlled by the first HVAC controller, and each command acknowledgement corresponds to one of the command requests.

[0014] In an aspect of the invention, the communication and control module are connected to a second HVAC controller by the communication hub, where the communication and control module is configured to send one of a second set of command requests to the second HVAC controller, where each command request is an eight-byte structure comprising a one-byte identifier of the second HVAC controller and a one-byte first command, and the second HVAC controller is configured to send one of a second set of command acknowledgements to the communication and control module, whereeach command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a second set of six one-byte information segments, each segment containing information about the state of a second HVAC system controlled by the second HVAC controller, and each command acknowledgement corresponds to one of the command requests.

[0015] In another aspect of the invention, the communication and control module is configured to send a third command request to the first HVAC controller, where the third command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte third command to change the settings of the first HVAC system, and the first HVAC controller is configured to send a third command acknowledgement to the communication and control module, where the third command acknowledgement is an eight byte structure comprising a third acknowledgement identifier and a third set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller, and at least one of the third set of six one-byte information segments of the third command acknowledgement confirming the change of the settings of the first HVAC system .

[0016] In another aspect of the invention, the communication and control module is configured to send a fourth command request to the first HVAC controller, where the fourth command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte fourth command to change the settings of the first HVAC system.

[0017] In another aspect of the invention, the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at rate of at least 9600 baud.

[0018] In accord with the invention, there is provided a method of controlling an HVAC system, comprising: a communication and control module sending a first command request to a first HVAC controller; where the first command request is an eight-byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte firstcommand; the first HVAC controller sending a first command acknowledgement to the communication and control module; where the first command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containing information about the state of a first HVAC system; and the first HVAC system being controlled by the first HVAC controller.

[0019] In an aspect of the invention, the communication and control module sends a second command request to the first HVAC controller; where the second command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte second command; the first HVAC controller sending a second command acknowledgement to the communication and control module; where the second command acknowledgement is an eight byte structure comprising a one-byte second acknowledgement identifier and a second set of six one-byte information segments, each segment containing information about the state of the first HVAC system.

[0020] In an aspect of the invention, the communication and control module controller sends a third command request to the first HVAC controller; where the third command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte third command to change the settings of the first HVAC system; the first HVAC controller sending a third command acknowledgement to the communication and control module; where the third command acknowledgement is an eight byte structure comprising a third acknowledgement identifier and a third set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller, and at least one of the third set of six one-byte information segments of the third command acknowledgement confirming the change of the settings of the first HVAC system.

[0021] In another aspect of the invention, the communication and control module controller sends a fourth command request to the first HVAC controller; where the fourth command request is an eight byte structure comprising a one-byte identifier of the firstHVAC controller and a one-byte fourth command to change the settings of the first HVAC system .

[0022] In another aspect of the invention, the communication and control module is in communication with the first HVAC controller via a communication hub, and the communication and control module being in communication with a second HVAC controller via the communication hub, the second HVAC controller controlling a second HVAC system; the communication and control module sending a fourth command request to the second HVAC controller; where the fourth command request is an eight-byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte first command; the second HVAC controller sending a fourth command acknowledgement to the communication and control module; where the fourth command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containing information about the state of a second HVAC system.

[0023] In another aspect of the invention, the first HVAC controller and the second HVAC controller are connected in parallel to the communication and control module.

[0024] In another aspect of the invention, the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at a 9600 baud rate. In still another aspect of the invention, the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at rate of at least 9600 baud.

[0025] In accord with the invention, there is provided a method of controlling an HVAC system, comprising: a communication and control module sending one of a first set of command requests to a first HVAC controller; where each command request is an eightbyte structure comprising a one-byte identifier of the first HVAC controller and a one-byte first command; the first HVAC controller sending one of a first set of command acknowledgements to the communication and control module; where each command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containinginformation about the state of a first HVAC system controlled by the first HVAC controller, and each command acknowledgement corresponding to one of the command requests.

[0026] In an aspect of the invention, the communication and control module is connected to the first HVAC controller by a communication hub, and the communication and control module being connected to a second HVAC controller by the communication hub; the communication and control module sending one of a second set of command requests to the second HVAC controller; where each command request is an eight-byte structure comprising a one-byte identifier of the second HVAC controller and a one-byte first command; the second HVAC controller is sending one of a second set of command acknowledgements to the communication and control module; where each command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a second set of six one-byte information segments, each segment containing information about the state of a second HVAC system controlled by the second HVAC controller, and each command acknowledgement corresponding to one of the command requests.

[0027] In another aspect of the invention, the communication and control module controller sends a third command request to the first HVAC controller; where the third command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte third command to change the settings of the first HVAC system; the first HVAC controller sending a third command acknowledgement to the communication and control module; where the third command acknowledgement is an eight byte structure comprising a third acknowledgement identifier and a third set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller, and at least one of the third set of six one-byte information segments of the third command acknowledgement confirming the change of the settings of the first HVAC system.

[0028] In another aspect of the invention, the communication and control module sends a fourth command request to the first HVAC controller; where the fourth command requestis an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte fourth command to change the settings of the first HVAC system.

[0029] In another aspect of the invention, the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at rate of at least 9600 baud.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Embodiments herein will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the claims, wherein like designations denote like elements, and in which:

[0031] Figure 1 is a figurative view of a general HVAC system with multiple components, sensors and controllers, and a controller;

[0032] Figure 2 is an illustration of the basic steps of the HVAC control system;

[0033] Figure 3 is an illustration of the setup of the HVAC control system;

[0034] Figure 4 is a schematic of the communication and control module connected to multiple HVAC systems through a communication hub;

[0035] Figure 5 illustrates the structure of each communication;

[0036] Figure 6 illustrates a command request to request a first set of information about an HVA system and the corresponding command acknowledgement;

[0037] Figure 7 illustrates a command request to control settings of an HVAC system and the corresponding command acknowledgement;

[0038] Figure 8 illustrates a command request to request a second set of information about an HVAC system and the corresponding command acknowledgement; and

[0039] Figure 9 is an illustration of the data structure for recovering from a power failure.DETAILED DESCRIPTION OF THE INVENTION

[0040] Figure 1 is a figurative view of a general HVAC system with multiple components, sensors and controllers. Turning to Figure 1, there is an HVAC system 1, which includes components 2, 3, 4, 5, 6 and 7. There is an HVAC controller 8 that communicates with and directly controls components 2-7, or communicates with and controls optional controllers 9 through 12 which in turn control specific components of the HVAC system 1. HVAC controller 8 is also in communication with sensors 13, 14, 15, and 16 sense the status of the HVAC components or the environment encountered by the HVAC system.

[0041] Figures 2 and 3 show a high level design of the inventive communication and control system. Turning to Figure 2, a command request is sent to an HVAC controller in step 20, a command acknowledgement is sent back from the HVAC controller to the communication and control module in step 21 , and step 22 is return to step 20, so that a command request is sent repeatedly to the HVAC controller(s).

[0042] Turning to Figure 3, the command requests in step 20 is sent from a communication and control module 30 to an HVAC controller 32, which corresponds to HVAC controller 8 in Figure 1 , and the command acknowledgement is sent back from the HVAC controller 32 to communication and control module 30.

[0043] The communication and control module 30 may itself include a plurality of communication and control modules; however, it must include a module for communication across a wire with multiple HVAC systems. Similarly, as set out in association with Figure 1, the HVAC controller 32 (HVAC controller 8 in Figure 1) can include a plurality of control and communication modules but should allow communication with and control of the sensors and components in the HVAC system.

[0044] As may be seen in Figures 2 and 3, in a preferred embodiment the time between communication and control module 30 sending a command request and HVAC controller 32 sending a command acknowledgement is between 30 and 50 ms. In a preferred embodiment, the time between HVAC controller 32 sending a commandacknowledgement and communication and control module 30 sending the next command request is between 10 and 20 ms. In a preferred embodiment, the communication and control module 30 sends command requests every 80 ms.

[0045] In a preferred embodiment, the communications between the communication and control module 30 and the HVAC controller(s) 32 should be by an RS-485 (2 line). In a preferred embodiment, the communication speed is 9600 baud rate (or bits per second). In a preferred embodiment, the data standard is 8 bit data, 1 stop bit, none parity.

[0046] Figure 4 shows multiple HVAC systems connected to communication and control module 30 via a communication hub. Turning to Figure 4, communication and control module 30 is in communication with a communication hub 40, which in turn is in parallel communication with multiple HVAC systems 41, 43, 45 and 47 via HVAC controllers 42, 44, 46 and 48 (each an instantiation of HVAC controller(s) 32).

[0047] The multiple HVAC systems being in parallel communication with communication and control module 30 has numerous advantages over serial connection. If one HVAC system malfunctions (or the HVAC controller of that HVAC system malfunctions), HVAC systems downstream from the malfunctioning HVAC system are not cut off. Furthermore, as will be discussed below, parallel design is important to the scalability of the overall communication and control system, and allows for the graceful updating of communication and control structure and software.

[0048] Figure 5 illustrates the structure of each communication. Turning to Figure 5, each communication 50 - whether a command request or a command acknowledgement - is structured as an eight byte data structure 52, each byte having 8 bits 54. One byte (illustrated in Figure 5 as byte 07) is a CHECKSUM byte, which is used to check the integrity of the received communication, and is known to a person skilled in the art. One byte (illustrated in Figure 5 as Byte 00) is reserved for a Command or Acknowledgement. The other bytes, labelled Byte 01 through Byte 06, are used for different purposes as set out below.

[0049] Figure 6 illustrates the communication structure of an HVAC System Status Request. Turning to Figure 6, structure 60 is the structure of a command request sent by communication and control module 30 to obtain information about the status of the HVAC system. Byte 00 is a Command 61 that directs the HVAC system identified in Byte 01 (HVAC System ID) to send a pre-defined first set of information back to communication and control module 30. In this case, Bytes 02 through Byte 06 of structure 60 are left blank (usually zeros, also described as placeholders).

[0050] By varying the Command 61, the communication and control module 30 can request different sets of information to be sent back from the recipient HVAC system identified in Byte 01 of communication structure 60.

[0051] The communication structure 60 is sent out to all connected HVAC systems 41, 43, 45, 47, etc. through the parallel communication hub 40 illustrated in Figure 4, and so is received by all connected HVAC systems. HVAC systems 41, 43, 45 and 47 (or, equivalently, their HVAC controllers 42, 44, 46 and 48 (each an instantiation of HVAC controller(s) 32) are configured so that only the HVAC system identified in Byte 01 of communication structure 60 responds with a Command Acknowledgement.

[0052] Returning to Figure 6, the communication structure of the Command Acknowledgement to be sent by the HVAC controller in response to a Command Request with command 61 is communication structure 62. One byte, illustrated as Byte 00 in communication structure 62, contains an acknowledgement identifier 63, which specifies which Command (Byte 00 in communication structure 60) the HVAC system is responding to. Another byte, illustrated as Byte 01 (labelled Controller Status in Figure 6) in communication structure 62, contains information on the status of the responsive HVAC system controller 32. The remaining bytes (apart from the CHECKSUM byte) contain information about the state of the HVAC system.

[0053] As each byte contains 8 bits, the system can be configured to deliver multiple pieces of information in each byte. In a preferred embodiment, the Controller Status (Byte 01 in communication structure 62) uses bit 7 to indicate whether the power is on (1 ) or off (0); bits 4 and 5 to indicate an error state (no error = 00, moderate error = 01 , severe error= 10); and bit 0 to indicate the status of whether the HVAC system in in away mode (unset = 0, set = 1).

[0054] In some cases, the information about the state of the HVAC system has to occupy an entire byte. In a preferred embodiment, bytes are used to communicate information about temperatures: the temperature of the General Mode (illustrated as Byte 02 of communication structure 62), the temperature of the Away Mode (illustrated as Byte 03 of communication structure 62), and current space Temperature (illustrated as Byte 04 of communication structure 62). In a preferred embodiment, each of these takes up an entire byte, and is sent in BCD (binary coded decimal) format. In another preferred embodiment, Byte 05 in communication structure 62 contains information on the Operation Mode (0x01 = Cooling, 0x02 = Heating, and 0x03 = Fan). In another preferred embodiment, Byte 06 in communication structure 62 indicates the fan speed (0x01 = Low, 0x02 = Medium, 0x03 = High, 0x04 = Auto, 0x05= On).

[0055] This preferred embodiment is given below in Table 1.Table 1

[0056] Figure 7 illustrates the communication structure of an HVAC System Control Request. Turning to Figure 7, structure 70 is the structure of a command request sent by communication and control module 30 to change setting(s) of the HVAC system. Turning to Figure 7, Byte 00 is a Command 71 that directs the HVAC system identified in Byte 01 (HVAC System ID) to change the settings of the HVAC system, and to send back a predefined set of information back to communication and control module 30.

[0057] In a preferred embodiment, the Command 71 instructs the HVAC system to set at least one of the room temperature setpoint, operation mode, fan speed and HVAC system on / off status.

[0058] The communication structure 70 is sent out to all connected HVAC systems 41, 43, 45, 47, etc. through the parallel communication hub 40 illustrated in Figure 4, and so is received by all connected HVAC systems. HVAC systems 41, 43, 45 and 47 (or, equivalently, their HVAC system communication and control modules 42, 44, 46 and 48 (each an instantiation of HVAC system communication and control module(s) 32)) are configured so that only the HVAC system identified in Byte 01 of communication structure 70 responds with a Command Acknowledgement.

[0059] Returning to Figure 7, the communication structure of the Command Acknowledgement to be sent by the HVAC system in response to an HVAC Control Request is communication structure 72. One byte, illustrated as Byte 00 in communication structure 72, contains an acknowledgement identifier 73, which specifies which Command (Byte 00 in communication structure 70, labelled 71) the HVAC system is responding to. Another byte, illustrated as Byte 01 (labelled as Controller Status in Figure 7) in communication structure 72, contains information on the status of the responsiveHVAC controller 32. The remaining bytes (apart from the CHECKSUM byte) contain information about the state of the HVAC system.

[0060] As each byte contains 8 bits, the system can be configured to deliver multiple pieces of information in each byte. In a preferred embodiment, the Controller Status (Byte 01 in communication structure 72) uses bit 7 to indicate whether the power is on (1 ) or off (0); bits 4 and 5 to indicate an error state (no error = 00, moderate error = 01 , severe error = 10); and bit 0 to indicate the status of whether the HVAC system in in away mode (unset = 0, set = 1).

[0061] In some cases, the information about the state of the HVAC system has to occupy an entire byte. In a preferred embodiment, bytes are used to communication information about temperatures: the temperature of the General Mode (illustrated as Byte 02 of communication structure 72), the temperature of the Away Mode (illustrated as Byte 03 of communication structure 72), and current space Temperature (illustrated as Byte 04 of communication structure 72). In a preferred embodiment, each of these takes up an entire byte, and is sent in BCD (binary coded decimal) format. In another preferred embodiment, Byte 05 in communication structure 72 contains information on the Operation Mode (0x01 = Cooling, 0x02 = Heating, and 0x03 = Fan). In another preferred embodiment, Byte 06 in communication structure 72 indicates the fan speed (0x01 = Low, 0x02 = Medium, 0x03 = High, 0x04 = Auto, 0x05= On).

[0062] This preferred embodiment for communication structure 72 is given below in Table 2.&Table 2

[0063] Through communication structure 72, the communication and control module 30 receives confirmation that the HVAC system has actually implemented the changes it was instructed to implement, as these changes should be reflected in the information in Bytes 02-06 in communication structure 72.

[0064] In the embodiment described above, the information in Bytes 01-06 of communication structure 62 and communication structure 72 are identical. This is a preferred embodiment, as this allows the communication and control module 30 toconfirm the effect of its Control Request on the actual operation of the HVAC system. However, as a general matter it is not required for the information in Bytes 01-06 of communication structure 62 and communication structure 72 to be identical.

[0065] The communication and control module 30 can send different Command Requests to receive different sets of information about the state of the HVAC system. This is illustrated in Figure 8. Turning to Figure 8, communication structure 80 is the structure of a command request sent by communication and control module 30 to obtain a second set of information about an HVAC system. Byte 00 is a Command 81 that directs the HVAC system identified in Byte 01 (labelled HVAC System ID in Figure 8) to send a predefined second set of information back to communication and control module 30. In this case, Bytes 02 through Byte 06 of structure 80 are left blank (usually zeros, also described as placeholders).

[0066] Note that in this case, Command 81 is different from Command 61 (and Command 71 ), since Command 81 is requesting a different set of information from the HVAC system compared to Command 61.

[0067] The communication structure 80 is sent out to all connected HVAC systems 41, 43, 45, 47, etc. through the parallel communication hub 40 illustrated in Figure 4, and so is received by all connected HVAC systems. HVAC systems 41, 43, 45 and 47 (or, equivalently, their HVAC system communication and control modules 42, 44, 46 and 48 (each an instantiation of HVAC system communication and control module(s) 32) are configured so that only the HVAC system identified in Byte 01 of communication structure 80 responds with an Command Acknowledgement.

[0068] Returning to Figure 8, the communication structure of the Command Acknowledgement to be sent by the HVAC system in response to aFack command 81 is communication structure 82. One byte, illustrated as Byte 00 in communication structure 82, contains an acknowledgement identifier 83, which specifies which Command (Byte 00 in communication structure 80, labelled 81) the HVAC system is responding to. The remaining bytes (apart from the CHECKSUM byte) contain information about the state of the HVAC system.

[0069] As each byte contains 8 bits, the system can be configured to deliver multiple pieces of information in each byte.

[0070] In a preferred embodiment, Byte 01 in communication structure 82 reports the humidity percentage as a byte in BCD format. In a preferred embodiment, Bytes 02 through 05 report temperature values (for example refrigerant temperature, discharge air temperature, leaving water temperature), all as bytes in BCD format. In a preferred embodiment, Byte 06 in communication structure 82 reports on conditions and / or alarms, and in a preferred embodiment Byte 06 in communication structure 82 uses bits 0, 1 and 2 to indicate alarms (for example, no error = 000, error code #1 = 001, error code #2 = 010, error code #3 = 011, error code #4 = 100, error code #5 = 011, error code #6 = 110, and error code #7 = 111) and uses bits 3 through 7 to indicate a condition (for example, bit 7 is condition #1 (on=1 , off=0), bit 6 is condition #2 (on=1 , off=0), bit 5 is condition #3 (on=1, off=0), bit 4 is condition #4 (on=1, off=0), bit 3 is condition #5 (on=1, off=0)). In the preceding embodiment, a condition reflects the state of the HVAC, while an alarm generally indicates a failure of a component in the HVAC system.

[0071] This preferred embodiment for communication structure 82 is given below in Table 3.Table 3Recovery from Power Failure

[0072] The communication and control system disclosed above can also be used to recover from a power failure. In some cases, the memory in the HVAC controller is volatile (and thius erased by a power failure), in which case the communication and control module 30 needs to re-establish communication with the HVAC controller and then restore the settings of the HVAC system. In a preferred embodiment, the memory in communication and control module 30 is non-volatile, and so is not erased by a power failure.

[0073] This is illustrated in Figure 9. Turning to Figure 9, the communication and control module 30 sends a communication structure 90 to the HVAC systems (as seen in Figure 4). In communication structure 90, Byte 00 is a Command 91 that requests the HVAC system identified in Byte 01 (HVAC System ID) to accept the settings in Bytes 02 to 06 in communication structure 90.

[0074] In a preferred embodiment, Byte 02 in communication structure 90 is the Temperature of the General Mode of the HVAC system, which takes up a byte and is in BCD format. In a preferred embodiment, this is the last value as set by the user of the HVAC system. In a preferred embodiment, Byte 03 in communication structure 90 is the Temperature of the Away Mode, which takes up a byte and is in BCD format. In a preferred embodiment, this is the last value as set by the user of the HVAC system. In a preferred embodiment, Byte 04 in communication structure 90 is the Controller Status. In a preferred embodiment, the Controller Status (Byte 04 in communication structure 90) uses bit 7 to indicate whether the power is on (1) or off (0); bits 4 and 5 to indicate an error state (no error = 00, moderate error = 01, severe error = 10); and bit 0 to indicatethe status of whether the HVAC system in in away mode (unset = 0, set = 1). In a preferred embodiment, Byte 05 in communication structure 90 contains information on the Operation Mode. In a preferred embodiment, this is 0x01 = Cooling, 0x02 = Heating, and 0x03 = Fan. In a preferred embodiment, Byte 06 of communication structure 90 indicates the fan speed. In a preferred embodiment, this is 0x01 = Low, 0x02 = Medium, 0x03 = High, 0x04 = Auto, 0x05= On.

[0075] This preferred embodiment for communication structure 92 is given below in Table 4._ _Table 4

[0076] In a preferred embodiment, if the memory in the HVAC controller is volatile and erased by a power failure, the HVAC controller should not respond to command requests for HVAC system status (as discussed in association with Figures 6 and 8 above) untilthe HVAC system’s settings are restored by communication and control module 30 via command structure 90. In a preferred embodiment, once power is restored the communication structure 91 is sent to the HVAC system every minute until a valid response is received from the HVAC controller in response to a command request for HVAC system status (as discussed in association with Figures 6 and 8 above) confirming that the settings in the HVAC system have been restored.

[0077] This approach takes advantage of the parallel approach to communications, and also can work with HVAC systems manufactured or installed by different companies, which may have different vulnerabilities to power failures and / or may be able to automatically restore settings in response to a communication structure 90. Even in cases where one of the HVAC systems refuses to restore settings (for whatever reason) or simply will not work following a power failure, the overall system is not broken and will continue to work for the other HVAC systems.

[0078] This approach is scalable. The number of HVAC systems that can be handled by this system is equal to the number of unique HVAC System IDs: as this one byte long, the system can handle 256 HVAC Systems.

[0079] This approach is also scalable, in that changes to the list of commands can be implemented at the level of communication and control module 30, and this will not break the system if some (or even all) of the HVAC controllers do not implement changes to recognize the new commands. The HVAC controller(s) will simply ignore those commands until the HVAC controller(s) 32 are updated (typically by the manufacturer of the HVAC system, or a maintenance person, or by the administrator of the overall communication and control system) to understand and implement the new commands.

[0080] The system can also be used to gracefully update the software on the HVAC controllers (assuming that the HVAC controllers are configured to accept software updates). A command structure is created and sent to the HVAC controllers that instructs the HVAC controllers 32 to download and install a software update. In a preferred embodiment, the command structure includes a link to the location of the software update. This will not break the system if some (or even all) of the HVAC controllers do notimplement the software updated; the HVAC controller(s) will simply ignore those commands until the HVAC controller(s) 32 are updated (typically by the manufacturer of the HVAC system, or a maintenance person, or by the administrator of the overall communication and control system) to understand and implement the new command to update the software.

[0081] In an alternative embodiment, the updates on the software on the HVAC controllers can be accomplished by creating and sending a command structure to the HVAC controller(s) that instructs the HVAC controller(s) 32 to prepare to accept an update and acknowledge receipt and implementation of this Command. The communication and command module 30 then sends a series of command structures to the HVAC controller that includes the software update in Bytes 02-06 of the command structures, which are used by the HVAC controller(s) 32 to perform the software update. This approach will not break the system if some (or even all) of the HVAC systems do not implement the software updated; the HVAC systems will simply ignore those commands until the HVAC controller 32 is updated (typically by the manufacturer of the HVAC system, or a maintenance person, or by the administrator of the overall communication and control system) to understand and implement the new command to update the software.

[0082] The parallel system of communication with the HVAC systems 41, 43, 45 and 47 and their HVAC controllers 42, 44, 46 and 48 (as seen in Figure 4) also means that communications between the communication and control module 30 and the HVAC systems 41 , 43, 45 and 47 are faster than if the HVAC systems were connected in series, since there is no need for a communication to be passed down a chain.

[0083] In this system, as seen in Figures 2 and 3, Command requests can be sent as often as every 80 ms. Communications between the command and control module 30 and the HVAC controller(s) 32 are at a rate of 9600 or greater baud, which the applicants believe is faster than seen in the industry today and is a significant improvement over existing HVAC control systems. As a further result, the communication and control functions are operating on a continuous (or, technically, semi-continuous) basis.

[0084] Throughout this description, there are examples of communication structures given that are eight bytes long and identify certain information as located in Byte 00 through Byte 07. A person skilled in the art will realize that the ordering of the information as Bytes 00 through 07 are for convenience, and that in an actual implementation the described Bytes 00-07 can be in any order within the communication structure.

Claims

WHAT IS CLAIMED IS:

1. An HVAC control and communication system, comprising:a communication and control module connected to a first HVAC controller by a communication hub, where the communication and control module is configured to send a first command request to the first HVAC controller, where the first command request is an eight-byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte first command, and the first HVAC controller is configured to send a first command acknowledgement to the communication and control module, where the first command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containing information about the state of a first HVAC system controlled by the first HVAC controller.

2. The HVAC control system of claim 1 , further comprising:the communication and control module being configured to send a second command request to the first HVAC controller, where the second command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte second command, and the first HVAC controller is configured to send a second command acknowledgement to the communication and control module, where the second command acknowledgement is an eight byte structure comprising a one-byte second acknowledgement identifier and a second set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller.

3. The HVAC control system of claim 2, further comprising the communication and control module being configured to send a third command request to the first HVAC controller, where the third command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte third command to change the settings of the first HVAC system, and the first HVAC controller is configured to send a third command acknowledgement to the communication and control module, where the thirdcommand acknowledgement is an eight byte structure comprising a third acknowledgement identifier and a third set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller, and at least one of the third set of six one-byte information segments of the third command acknowledgement confirming the change of the settings of the first HVAC system.

4. The HVAC control system of claim 3, further comprising the communication and control module being configured to send a fourth command request to the first HVAC controller, where the fourth command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte fourth command to change the settings of the first HVAC system.

5. The HVAC control system of claim 3, further comprising: a second HVAC controller that controls a second HVAC system, the second HVAC controller being connected to the communication and control module by the communication hub.

6. The HVAC control system of claim 5, where the first HVAC controller and the second HVAC controller are connected in parallel to the communication and control module.

7. The HVAC control system of claim 5, where the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at a 9600 baud rate.

8. The HVAC control system of claim 5, where the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at rate of at least 9600 baud.

9. An HVAC control system comprising:a communication and control module connected to a first HVAC controller by a communication hub, where the communication and control module is configured to send one of a first set of command requests to the first HVAC controller, where each command request is an eight-byte structure comprising a one-byte identifier of the first HVACcontroller and a one-byte first command, and the first HVAC controller is configured to send one of a first set of command acknowledgements to the communication and control module, where each command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containing information about the state of a first HVAC system controlled by the first HVAC controller, and each command acknowledgement corresponds to one of the command requests.

10. The HVAC control system of claim 9 comprising:the communication and control module connected to a second HVAC controller by the communication hub, where the communication and control module is configured to send one of a second set of command requests to the second HVAC controller, where each command request is an eight-byte structure comprising a one-byte identifier of the second HVAC controller and a one-byte first command, and the second HVAC controller is configured to send one of a second set of command acknowledgements to the communication and control module, where each command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a second set of six one-byte information segments, each segment containing information about the state of a second HVAC system controlled by the second HVAC controller, and each command acknowledgement corresponds to one of the command requests.

11. The HVAC control system of claim 10, further comprising the communication and control module being configured to send a third command request to the first HVAC controller, where the third command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte third command to change the settings of the first HVAC system, and the first HVAC controller is configured to send a third command acknowledgement to the communication and control module, where the third command acknowledgement is an eight byte structure comprising a third acknowledgement identifier and a third set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller, and at least one of the third set of six one-byte information segmentsof the third command acknowledgement confirming the change of the settings of the first HVAC system.

12. The HVAC control system of claim 10, further comprising the communication and control module being configured to send a fourth command request to the first HVAC controller, where the fourth command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte fourth command to change the settings of the first HVAC system.

13. The HVAC control system of claim 10, where the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at rate of at least 9600 baud.

14. A method of controlling an HVAC system, comprising:a communication and control module sending a first command request to a first HVAC controller;where the first command request is an eight-byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte first command;the first HVAC controller sending a first command acknowledgement to the communication and control module;where the first command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containing information about the state of a first HVAC system; andthe first HVAC system being controlled by the first HVAC controller.

15. The method claim 14, further comprising:the communication and control module sending a second command request to the first HVAC controller;where the second command request is an eight byte structure comprising a one- byte identifier of the first HVAC controller and a one-byte second command;the first HVAC controller sending a second command acknowledgement to the communication and control module;where the second command acknowledgement is an eight byte structure comprising a one-byte second acknowledgement identifier and a second set of six one-byte information segments, each segment containing information about the state of the first HVAC system.

16. The method of claim 15, further comprising:the communication and control module sending a third command request to the first HVAC controller;where the third command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte third command to change the settings of the first HVAC system;the first HVAC controller sending a third command acknowledgement to the communication and control module;where the third command acknowledgement is an eight byte structure comprising a third acknowledgement identifier and a third set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller, and at least one of the third set of six one-byte information segments of the third command acknowledgement confirming the change of the settings of the first HVAC system.

17. The method of claim 16, further comprising:the communication and control module sending a fourth command request to the first HVAC controller;where the fourth command request is an eight byte structure comprising a one- byte identifier of the first HVAC controller and a one-byte fourth command to change the settings of the first HVAC system.

18. The method of claim 16, further comprising:the communication and control module being in communication with the first HVAC controller via a communication hub, and the communication and control module being in communication with a second HVAC controller via the communication hub, the second HVAC controller controlling a second HVAC system;the communication and control module sending a fourth command request to the second HVAC controller;where the fourth command request is an eight-byte structure comprising a one- byte identifier of the first HVAC controller and a one-byte first command;the second HVAC controller sending a fourth command acknowledgement to the communication and control module;where the fourth command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containing information about the state of a second HVAC system.

19. The method of claim 18, where the first HVAC controller and the second HVAC controller are connected in parallel to the communication and control module.

20. The method of claim 18, where the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at a 9600 baud rate.

21. The method of claim 18, where the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at rate of at least 9600 baud.

22. A method of controlling an HVAC system, comprising:a communication and control module sending one of a first set of command requests to a first HVAC controller;where each command request is an eight-byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte first command;the first HVAC controller sending one of a first set of command acknowledgements to the communication and control module;where each command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a first set of six one-byte information segments, each segment containing information about the state of a first HVAC system controlled by the first HVAC controller, and each command acknowledgement corresponding to one of the command requests.

23. The method of claim 22, further comprising:the communication and control module being connected to the first HVAC controller by a communication hub, and the communication and control module being connected to a second HVAC controller by the communication hub;the communication and control module sending one of a second set of command requests to the second HVAC controller;where each command request is an eight-byte structure comprising a one-byte identifier of the second HVAC controller and a one-byte first command;the second HVAC controller is sending one of a second set of command acknowledgements to the communication and control module;where each command acknowledgement is an eight byte structure comprising a one-byte first acknowledgement identifier and a second set of six one-byte information segments, each segment containing information about the state of asecond HVAC system controlled by the second HVAC controller, and each command acknowledgement corresponding to one of the command requests.

24. The method of claim 23, further comprising:the communication and control module sending a third command request to the first HVAC controller;where the third command request is an eight byte structure comprising a one-byte identifier of the first HVAC controller and a one-byte third command to change the settings of the first HVAC system;the first HVAC controller sending a third command acknowledgement to the communication and control module;where the third command acknowledgement is an eight byte structure comprising a third acknowledgement identifier and a third set of six one-byte information segments, each segment containing information about the state of the first HVAC system controlled by the first HVAC controller, and at least one of the third set of six one-byte information segments of the third command acknowledgement confirming the change of the settings of the first HVAC system.

25. The method of claim 24, further comprising:the communication and control module sending a fourth command request to the first HVAC controller;where the fourth command request is an eight byte structure comprising a one- byte identifier of the first HVAC controller and a one-byte fourth command to change the settings of the first HVAC system.

28. The method of claim 23, where the communication between the communication and control module and the first HVAC controller and the second HVAC controller is at rate of at least 9600 baud.

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