EFFICIENT MULTI-ZONE MULTI-VELOCITY HVAC CONTROL METHOD AND APPARATUS

Abstract

The present invention provides heating and cooling conditioning control in a multiple zone HVAC system to achieve enhanced user comfort and energy efficiency. In particular, the present invention provides a multiple zone HVAC control apparatus that senses and responds to changes in duct air pressure in order to prevent undesirable zone conditioning, energy loss, and register noise. The present invention offers particular benefit in high and medium velocity HVAC environments which typically suffer from pronounced deficiencies when zone demands diverge. Due to its ability to respond to changes in duct pressure, the present invention permits the conditioning of an increased number of zones without degradation in performance or user comfort. Additionally, the present invention provides a means to control elements within a multiple zone HVAC system including but not limited to heating and cooling sources, air circulator fans, zone dampers, and circulating pumps to achieve desired zone conditioning.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to control systems used to regulate heating and cooling in HVAC systems. Specifically, the present invention relates to methods and apparatus employed to control the temperature and flow of forced air through duct systems for the regulation of indoor climate. The application of the present invention for the regulation of indoor temperature is appropriate where a forced air heating or cooling source is available to provide air flow through a duct system. This invention finds particular application where the forced air duct system is divided into zones each requiring discrete comfort conditioning, employs high or medium velocity small diameter ducts, and where increased efficiency and reduced noise in the delivery of said conditioning is desirable.

2. Description of the Prior Art

Prior art embodiments of HVAC control systems are generally capable of switching heating and cooling sources on and off while increasing or decreasing air circulator fan speed through 2 to 3 steps typically, occasionally more, in order to achieve desired indoor conditioning as demanded by a user programmed thermostat. Multiple zone versions of the above are available wherein each zone is equipped with a thermostat in order to achieve isolated conditioning. Dampers are typically used to control the flow of temperature conditioned air to each zone in the multiple zone system. When conditioning demands diverge between zones in a prior art multiple zone system, the dampers are used to partially close off those zones deemed by the system to require reduced air flow. The system is unable to fully close dampers due to the need to retain the ability to vent excess air in the system. As a result, undesirable conditioning may be delivered to zones which do not demand it. Due to the reduction in the capacity of the duct system to process excess air flow upon the partial closure of one or more dampers, the air pressure in the system increases, often dramatically. The increased pressure in the duct system subsequently increases the rate of air flow through the remaining open dampers causing significantly undesirable conditioning performance and noise at registers. These deficiencies are particularly pronounced in high and medium velocity small diameter duct systems which are increasingly incorporated in new home constructions. The number of zones in such systems is limited due to the amplification of the deficiencies with the addition of each zone. Further, there is a significant drop in the overall energy efficiency of the multiple zone heating and cooling system when undesirable conditioning and noise are present.

SUMMARY OF THE INVENTION

The present invention provides a multiple zone heating and cooling control system and method wherein undesirable conditioning due to damper operation is reduced or eliminated and noise due to higher pressure air flow is significantly attenuated. In particular, the present invention provides a means to monitor changes in pressure due to damper operation and air circulator fan speed and to reactively adjust air circulator fan speed in order to maintain a desirable static pressure. Unlike prior art embodiments and due to its ability to maintain a desirable static pressure, the present invention permits the full closure of zone dampers as required by the operation of the multiple zone HVAC system. Thereby, this invention is able to provide significantly greater user comfort and energy efficiency, particularly in higher pressure high and medium velocity HVAC systems, permitting an increase in the number of zones while delivering performance generally free of the deficiencies of the prior art.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of the implementation of an embodiment of an efficient multiple zone and multiple velocity HVAC control apparatus within an HVAC system.

FIG. 2 is a block diagram illustrating the internal components of an embodiment of an efficient multiple zone and multiple velocity HVAC control apparatus.

FIG. 3 is a block diagram illustrating the internal components of an embodiment of an efficient multiple zone and multiple velocity HVAC control apparatus with additional features.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to better understand the embodiment of the present invention, an embodiment of an efficient multiple zone and multiple velocity HVAC control method and apparatus will be described with reference to FIGS. 1, 2, and 3. An embodiment of an implementation of an efficient multiple zone and multiple velocity HVAC control apparatus within an HVAC system is provided as in FIG. 1 comprised of a heating and/or cooling source 5, an air circulator fan with variable speed motor 7, a duct network 25 to direct airflow as illustrated by arrow 27, a pressure sensor 29, motorized dampers 9, 11, 13 and 15 servicing zones 1, 2, 3, and 4 respectively, thermostats 17, 19, 21, and 23, and controller board 31. Operation of said HVAC system is initiated by input from thermostats 17, 19, 21, and 23 providing real-time temperature and user desired temperature input to the controller board 31. Further data such as the static pressure in the duct network 25 is provided to the controller board 31 which in turn controls the operation of the heating and/or cooling source 5, the air circulator fan 7, and each of the motorized dampers 9, 11, 13 and 15 to condition each zone to achieve the closest approximations of the user desired temperatures as provided by thermostats 17, 19, 21, and 23 in zones 1, 2, 3, and 4 respectively. Zone 4, labeled ZONE N, in FIG. 1 is provided to illustrate that the number of zones is not limited by the capacity of the efficient multiple zone and multiple velocity HVAC control apparatus but by the configuration and intended application of the HVAC system. It is understood that the system could be equipped with a fifth, sixth, seventh, or more zones each equipped with dampers and thermostats to satisfy application requirements and each provided with similar zone conditioning as above without departing from the spirit of the present invention. It is further understood that the implementation of pressure sensing in the duct network 25 as provided by pressure sensor 29 providing pressure data to the controller board 31 for enhanced operation and performance of an HVAC system finds particular application in high and medium velocity small diameter duct environments but may be beneficially applied in low pressure low velocity systems without departing from the spirit of the present invention.

To provide greater understanding of the present invention, an embodiment of the efficient multiple zone and multiple velocity HVAC control apparatus is provided as in FIG. 2. A multiple zone HVAC controller board 37 is shown comprising a source control element 49, a fan control element 51, a damper control element 39, a pressure sensor input element 41, a thermostat input element 43, a power supply unit 45, and a controller processor element 47. Said source control element 49 provides the facility to switch a heating and/or a cooling source on and off as required by the conditioning demands of the user of an HVAC system. Said fan control element 51 provides a signal to an air circulator fan to increase or decrease fan speed thereby increasing or decreasing air flow in a duct network. Said fan control signal is a variable type such as pulse width modulated, 0-10V, or other proportional control scheme thereby providing a level of fan speed control range and granularity unattainable by typical step speed control means. Said damper control element 39 provides the facility to incrementally open or close or to fully open or close each motorized zone damper in a multiple zone HVAC system according to the independent requirements of each zone. Said pressure sensor input element 41 provides pressure sensor data representing the air pressure in the duct network of an HVAC system to the controller processor element 47 which in turn sends signals to fan control element 51 to adjust air circulator fan speed to maintain a desired static pressure as required. Said thermostat input element 43 provides real-time and user desired temperature data for each zone in a multiple zone HVAC system to said controller processor element 47 which in turn may adjust the elements of the HVAC system controlled by and through source control element 49, fan control element 51, and damper control element 39 in order to achieve the desired zone conditioning demanded by the user. Said power supply unit 45 provides sufficient voltage and current to the controller processor element 47 as required by the application and to allow said controller processor element 47 to send the necessary signals to the conditioning elements of the system including said source control element 49, fan control element 51, and damper control element 39. Said power supply unit 45 may or may not be physically implemented on the multiple zone HVAC controller board 37 and is shown simply to illustrate that said controller board 37 requires a power source. Generally, building HVAC systems provide a 24 VAC power source for the implementation of standard controller boards and such power sources would be sufficient for the power supply requirements of the present invention. Operation of the multiple zone and multiple velocity HVAC control apparatus by other power supply means sufficient to support its power requirements would not depart from the spirit of the present invention.

The specific adjustments made to fan speed, damper angle, and source selection by the multiple zone and multiple velocity HVAC control apparatus are made in response to input data provided by the thermostat input element 43 and the pressure sensor element 41 and are guided by the heating and cooling strategy as programmed by a technician into the controller processor element 47 typically at the time of installation of the apparatus. Said heating and cooling strategy is generally specific to the capacity, geometry, features, and application of the HVAC system and is further influenced by end user requirements and the climate in the region of application.

To provide greater understanding of the versatility of the present invention, another embodiment of the efficient multiple zone and multiple velocity HVAC control apparatus with additional features is provided as in FIG. 3. A multiple zone HVAC controller board 53 is shown comprising a source control element 69, a fan control element 71, a damper control element 55, a pressure sensor input element 57, a thermostat input element 59, a power supply unit 61, a pump control element 63, a building automation input element 65, and a controller processor element 67. Said source control element 69, fan control element 71, damper control element 55, pressure sensor input element 57, thermostat input element 59, and said power supply unit 61 provide similar functionality within the system as those same elements present in and as previously described with reference to FIG. 2. However, in this embodiment, an additional control element is provided in the form of said pump control element 63 which provides a signal to a variable speed circulating pump element in an HVAC system to modulate its speed in response to the conditioning requirements system. Also, an additional input source is provided in the form of said building automation input element 65 which provides data to said controller processor element 67. Said controller processor 67 uses data provided by said building automation input element 65 in conjunction with data provided by said pressure sensor input element 57 and said thermostat input element 59 to send signals to make adjustments to HVAC system elements controlled by said source control element 69, said fan control element 71, said damper control element 55, and said pump control element 63 as guided by a heating and cooling strategy to achieve optimum zone conditioning in a multiple zone HVAC system.

For an HVAC system embodiment based on the embodiment of the efficient multiple zone and multiple velocity HVAC control apparatus with additional features as provided in FIG. 3, the specific adjustments made to fan speed, damper angle, circulating pump speed, and source selection by the multiple zone and multiple velocity HVAC control apparatus are made in response to input data provided by the thermostat input element 59, the pressure sensor input element 57, and the building automation input element 65 and are guided by the heating and cooling strategy as programmed by a technician into the controller processor element 67 typically at the time of installation of the apparatus. Said heating and cooling strategy is generally specific to the capacity, features, geometry, and application of the HVAC system and is further influenced by end user requirements and the climate in the region of application.

Claims

1. An efficient multiple zone and multiple velocity HVAC control apparatus comprising:

(a) a source control element;

(b) a fan control element;

(c) a damper control element;

(d) a pressure sensor element;

(e) a thermostat input element;

(f) a controller processor;

(g) a power source.

2. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said source control element can switch a heating or cooling source on or off as required by the operation of an HVAC system.

3. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said fan control element can control the speed of an air circulator fan as required by the operation of an HVAC system.

4. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 3, wherein said fan control element uses a variable type signal such as a pulse width modulated or other proportional control scheme signal to control the speed of an air circulator fan.

5. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said damper control element facilitates the opening or closing of dampers permitting or restricting airflow to zones as required by the operation of a multiple zone HVAC system.

6. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 5, wherein said damper control element facilitates the incremental adjustment of damper angles to provide precision air flow regulation as required to zones in a multiple zone HVAC system.

7. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said pressure sensor element provides duct network air pressure data to said controller processor.

8. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said controller processor uses duct network air pressure data provided by said air pressure sensor element to identify deviations from a predefined optimal static air pressure level.

9. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said controller processor sends signals to said fan control element to increase or decrease fan speed in response to duct network air pressure data in order to correct deviations from a predefined static air pressure level for the optimal operation and performance of an HVAC system.

10. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said thermostat input element provides zone temperature data and user desired zone conditioning data to said controller processor.

11. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said controller processor uses zone temperature data provided by said thermostat input element to determine actions required to achieve user desired zone conditioning.

12. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said controller processor sends signals to any or all of said source control element, fan control element, and damper control element in response to temperature data provided by said thermostat input element in order to achieve user desired zone conditioning.

13. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said power source provides electrical power to the component elements of the control apparatus and is sufficient to allow said component elements to send control signals to components of an HVAC system for the optimal operation and performance thereof.

14. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said controller processor may also be configured to receive and act on data provided to it by building automation elements in an HVAC system.

15. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said controller processor may also be configured to send signals to a pump controller which in turn modulates the speed of a circulating pump in an HVAC system to achieve user desired zone conditioning.

16. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said controller processor is readily programmable by an HVAC technician to set the number of zones, the primary zone, the optimal static duct pressure, and the heating and cooling strategy.

17. An efficient multiple zone and multiple velocity HVAC control apparatus as in claim 1, wherein said apparatus may be implemented in either high velocity, medium velocity, or low velocity HVAC environments.

18. An efficient multiple zone and multiple velocity HVAC control method comprising:

(a) a primary zone element;

(b) a heating and cooling strategy.

19. An efficient multiple zone and multiple velocity HVAC control method as in claim 18, wherein a primary zone is selected by an installation technician and said primary zone element determines whether an HVAC system is in a heating or cooling mode of operation.

20. An efficient multiple zone and multiple velocity HVAC control method as in claim 18, wherein said heating and cooling strategy is programmed into a multiple zone HVAC control apparatus and said strategy is typically determined by the capacity, features, geometry, and specific application of an HVAC system and further determined by the requirements of the user and climactic factors in the region of application.