HVAC communication system

• US 20060124759A1
• Filed: 12/13/2005
• Published: 06/15/2006
• Est. Priority Date: 12/14/2004
• Status: Active Grant

• Current Assignee: Emerson Electric Company, Itron, Inc.
• Original Assignee: Emerson Electric Company
• Inventors: Rossi, John, Smith, Bradley, Ng, Howard, Barrett, Cecil, Mueller, Carl, Huddleston, Paul, Barton, Mark, Garozzo, James, House, Russell
• Granted Patent: US 7,163,158 B2
• Time in Patent Office: Days
• US Class Current: 236/51
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/47 Responding to energy costs
• CPC Class Codes: F24F 11/56 Remote control
• CPC Class Codes: F24F 11/59 for presetting
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 11/70 Control systems characterised by their outputs; Constructional details thereof
• CPC Class Codes: F24F 11/88 Electrical aspects, e.g. circuits

Abstract

A system for communicating across conventional HVAC wiring is provided. The system includes a communication device having a communication module capable of inducing low power, high frequency current signals into a single control wire coupling, for example, a thermostat with a compressor. The communication module includes a power supply module that draws power sufficient to operate the communication module from the existing HVAC wiring, so as to eliminate any need for batteries or external power sources. A second communication module may be coupled to the single control wire. The second communication module operates as a transceiver sending communication signals to, and receiving communication signals from, the communication module. In one embodiment, the communication module is disposed within a building, for example coupled to an electronic thermostat, while the second communication module is disposed outside the building near the compressor. The communication signals are RF modulated signals between 5 and 50 MHz so as to take advantage of and pass across parasitic capacitances found inherent in transformers or other coils disposed within HVAC loads.

Claims

1. A system for communicating across a single HVAC control wire coupling at least a HVAC control unit with a HVAC load unit, comprising:

a. a communication module capable of inducing a communication signal current into the single HVAC control wire; and

b. a receiver disposed at the HVAC load unit, the receiver being capable of receiving the communication signal current.

2. The system of claim 1, wherein the receiver is capable of inducing a second communication signal current into the single HVAC control wire.

3. The system of claim 2, further comprising a HVAC load unit actuation coil disposed serially between the communication module and the receiver.

4. The system of claim 1, wherein the communication signal current comprises a frequency modulated signal, wherein a peak value of the frequency modulated signal remains below a predetermined switch threshold, the predetermined switch threshold corresponding to a level capable of actuating a HVAC load switch in the HVAC control unit.

5. The system of claim 1, wherein the HVAC load unit comprises a device selected from the group consisting of a compressor, an air handler and a furnace, further wherein the HVAC control unit comprises a thermostat.

6. The communication system of claim 5, wherein the communication module is capable of coupling to the thermostat, further wherein the thermostat is configured to monitor operating characteristics selected from the group comprising total compressor usage, total furnace usage, total HVAC system usage, average compressor usage, average furnace usage, average HVAC system usage, peak compressor usage, peak furnace usage, peak HVAC system usage, time of compressor usage, time of furnace usage, time of HVAC system usage, cost of compressor usage, cost of furnace usage, cost of HVAC system usage, time of use schedule, temperature override information, hold override information, time of day information, diagnostic information, error messages, temperature profiling information, appliance control schedules, protocol handling messages, current HVAC operating modes, thermostat configuration flags, test commands and lockout commands.

7. The system of claim 6, further comprising an environmental sensor coupled to communication module, wherein the environmental sensor senses a change in environmental condition selected from the group consisting of temperature, humidity, smoke, light, audio, water level, weight, motion, pressure, electrical current, voltage, AC input frequency and chemical element presence.

13. The HVAC communication system of claim 1 wherein the amount of power is less than 55 milliwatts.

8. A HVAC communication system comprising:

a. a control module; and

b. a communication module coupled to the control module;

wherein the communication module is configured to communicate through the HVAC communication system by inducing current onto one HVAC control wire, wherein the current has a frequency of between 4 and 50 MHz.

9. The HVAC communication system of claim 8, wherein the HVAC system operates in conjunction with a HVAC load, further wherein the communication module comprises a communication transformer coupled serially with the control module and the HVAC load.

10. The HVAC communication system of claim 9, further comprising:

a. a thermal sensing element coupled to the control module;

b. at least one switch responsive to the thermal sensing element; and

c. a low-voltage AC input terminal coupled to the control module;

wherein when the at least one switch is closed, the HVAC load is actuated.

11. The HVAC communication system of claim 10, further comprising a power supply module coupled to the low-voltage AC input terminal, wherein the power supply module receives an amount of power from the low-voltage AC input terminal sufficient to operate the control module and the communication module.

12. The HVAC communication system of claim 11, wherein the amount of power is less than a predetermined threshold.

14. The HVAC communication system of claim 9, further comprising:

a. a thermostat coupled to the control module; and

b. a HVAC load coupled to the thermostat by way of a single wire running from a coil disposed within the HVAC load to one of the control terminal and the thermostat.

15. The HVAC communication system of claim 14, further comprising a second control module and a second communication module having a second communication transformer coupled serially with the single wire.

16. The HVAC communication system of claim 15, wherein the control module is coupled with the thermostat and is disposed within a building, further wherein the HVAC load and the second communication module are disposed outside the building.

17. The HVAC communication system of claim 15, wherein when the communication module is actuated, a communication signal is transmitted across the single wire and is received by the second communication module.

18. The HVAC communication system of claim 15, wherein when the second communication module is actuated a second communication signal is transmitted across the single wire and is received by the communication module.

19. A communication system, the communication system comprising:

a. a communication device comprising a plurality of terminals configured to couple to a plurality of HVAC control wires, the plurality of terminals comprising at least a low-voltage AC input terminal and a Y-line terminal;

b. a power supply coupled to the low-voltage AC input terminal, wherein power required to operate the communication system is drawn from the low-voltage AC input terminal;

c. a control module coupled to the power supply;

d. at least one switch coupled to the control module, wherein when the at least one switch is coupled between the low-voltage AC input terminal and the Y-line terminal;

e. a communication module coupled to the control module; and

f. a communication transformer coupled to the communication module, wherein a winding of the communication transformer is coupled serially with the Y-line terminal.

20. The communication system of claim 19, wherein the communication module comprises circuitry configured to couple a communication signal to the communication transformer, wherein the communication signal comprises a carrier signal having a frequency of between 5 and 50 MHz.

21. The communication system of claim 20, wherein the carrier signal has a frequency selected from the group consisting of between 8 and 12 MHz, between 18 and 25 MHz and between 44 and 46 MHz.

22. The communication system of claim 19, wherein the communication device is capable of coupling to a thermostat, further wherein the control module is configured to monitor operating characteristics of the thermostat, wherein the operating characteristics are selected from the group comprising total compressor usage, total furnace usage, total HVAC system usage, average compressor usage, average furnace usage, average HVAC system usage, peak compressor usage, peak furnace usage, peak HVAC system usage, time of compressor usage, time of furnace usage, time of HVAC system usage, cost of compressor usage, cost of furnace usage, cost of HVAC system usage, time of use schedule, temperature override information, hold override information, time of day information, diagnostic information, error messages, temperature profiling information, appliance control schedules, protocol handling messages, current HVAC operating modes, thermostat configuration flags, test commands and lockout commands.

23. The communication system of claim 19, further comprising an environmental sensor coupled to the control module, wherein the environmental sensor senses a change in environmental condition selected from the group consisting of temperature, humidity, smoke, light, audio, water level, weight, motion, pressure, electrical current, voltage, AC input frequency and chemical element presence, further wherein when the change in environmental condition exceeds a predetermined threshold, the control module actuates the communication module.

24. A HVAC system comprising:

a. at least one HVAC load;

b. an air handler coupled to the at least one HVAC load; and

c. a communication device coupled between the at least one HVAC load and the air handler, the communication device comprising;

i. an input terminal electrically coupled to the air handler;

ii. a Y-terminal electrically coupled to the HVAC load;

iii. a power supply module coupled to the input terminal;

iv. a communication module coupled to the power supply module;

v. a first signal transformer coupled to the communication module, wherein one winding of the first signal transformer is coupled serially with the Y-terminal; and

vi. a switch, wherein when the switch is closed, the HVAC load actuates.

25. The HVAC system of claim 24, further comprising a second signal transformer coupled serially with the Y-terminal;

and a second communication device coupled to the second signal transformer.

26. The HVAC system of claim 25, wherein the HVAC load is selected from the group consisting of heat pumps, furnaces and air conditioners.

27. The HVAC system of claim 26, wherein the HVAC load comprises an air conditioner, wherein the air conditioner comprises a contactor coil, wherein a Y-line couples the Y-terminal with one winding of the contactor coil.

28. The HVAC system of claim 25, wherein the communication module communicates with the Y-communication unit by way of low-power current modulation at a frequency of one of between 8 and 10 MHz, between 18 and 25 MHz and between 44 and 46 MHz.

29. The HVAC system of claim 25, wherein the second communication device is configured to receive energy consumption information from a energy provider and to communicate the energy consumption information across the Y-line to the communication module, wherein when the energy consumption information matches a predetermined criterion, the control module executes an operation selected from opening the switch and closing the switch.

30. The HVAC system of claim 25, wherein the communication module is configured so as to retrieve a received signal strength from the second communication device, and, where the received signal strength is below a predetermined threshold, to increase a transmitted signal strength.

31. The HVAC system of claim 25, wherein the communication module is configured so as to retrieve a received signal strength from the Y-communication unit, and, where the received signal strength is above a predetermined threshold, to decrease a transmitted signal strength.

32. The HVAC system of claim 25, wherein the second communication device is configured to communicate with one of a public switched telephone network, a wireless wide area network and a local area network.

33. The HVAC system of claim 25, wherein the second communication device comprises PLC circuitry for communication across electrical wiring.

34. A method of communicating across an HVAC system, the method comprising the steps of:

a. providing a communication device coupled serially with at least one wire of the HVAC system; and

b. inducing a current in the at least one wire;

wherein the current comprises an AC current having a frequency of between 5 and 50 MHz.

35. The method of claim 34, wherein the frequency is between 8 and 46 MHz.

36. The method of claim 34, further comprising the step of providing at least a second communication device coupled serially with the at least one wire of the HVAC system.

37. The method of claim 34, further comprising the step of receiving the current with the second communication device.

38. The method of claim 34, further comprising the step of inducing a current in the at least one wire with the second communication device.

39. A communication system, the communication system comprising:

a. a communication device comprising a plurality of terminals configured to couple to a plurality of HVAC control wires, the plurality of terminals comprising at least a low-voltage AC input terminal and a Y-line terminal;

b. a power supply connected to the low-voltage AC input terminal for providing power to the communication device;

c. at least one switch connected serially between the low voltage AC input terminal and the Y-line terminal such that when the switch is closed a low-voltage AC signal is conducted to the Y-line terminal;

d. a microprocessor capable of controlling the at least one switch;

e. a communication module coupled to and in communication with the microprocessor;

f. a communication transformer coupled to and in communication with the communication module, wherein the communication transformer comprises at least one winding that is serially coupled with the Y-line terminal; and

g. a thermostat coupled to the communication device, wherein the communication device is configured to transmit an energy provider override request to the thermostat.

40. The communication system of claim 39, wherein the thermostat is configured to communicate at least one of a command signal for actuating a load and a temperature set point to the communication device.

41. The communication system of claim 40, wherein the communication device is disposed within a sub-base of the thermostat, further wherein the communication device is configured to receive communication signals from an energy provider.