Patent Application
20080161977
The invention relates to heating, ventilation, and air conditioning (HVAC) equipment, and more particularly, to zone controllers for HVAC systems.
Many buildings, particularly relatively small buildings such as single-family houses, have a single HVAC unit that is controlled by a single thermostat. The HVAC unit typically comprises some type of fluid temperature modifying device, such as a furnace for heating air, a boiler for heating a liquid or steam, or an air conditioner having an evaporating coil for cooling air. If the fluid is air, it is typically ducted to various locations within the building, or if it is liquid or steam, it is typically piped to heat exchangers at various locations in the building. The thermostat in this type of space conditioning system is typically positioned at a location where the heating and cooling loads are representative of the entire structure. For example, the thermostat may be installed in an interior room away from windows and doors that would tend to influence the sensed temperature. The HVAC equipment then controls the heating and cooling of the entire structure according to the thermostat signal received from the single location.
However, a single thermostat location may not accurately represent the heating or cooling needs throughout the structure. Other locations of the building may have significantly greater or lower heating and cooling loads than exist at the location of the thermostat. For example, rooms having a larger surface area of windows, or rooms having exterior walls, may require greater heat inputs to maintain the desired temperature. Similarly, rooms facing south or west, or rooms that are on an upper story, may require greater cooling inputs to maintain the desired temperature. Where the HVAC equipment is controlled only by a single thermostat, the heating or cooling supplied to each individual area of the building will be based on the heating or cooling needs at the thermostat location and not on the actual heating and cooling needs of each individual area. As a consequence, the heating and cooling loads of individual areas of the structure may not be satisfied and the temperature of these areas will tend to deviate from the desired temperature.
In some situations, it may be desired to control different locations within a building at different temperatures. For example, rooms that are seldom occupied may not need to be maintained at the same temperature as rooms that are frequently occupied. Energy that is used to heat or cool these unoccupied rooms is not used effectively or economically. Also, rooms may be occupied by people having special temperature needs, such as an elderly person or an infant, that are preferably maintained at a different temperature than the rest of the building. However, a system that has only a single thermostat is generally unable to accurately control different locations in the building at different temperatures.
One known solution to this problem is to utilize HVAC zone control. Rather than having a single thermostat controlling the HVAC equipment, multiple thermostats are positioned at locations within the building that are expected to have different heating and cooling loads. Although it is possible that each of these thermostats could control a separate fluid temperature modifying device such as a separate furnace or air conditioner for each zone, such an approach is generally neither efficient nor economical. Rather, most commonly the ductwork or piping that is used to transmit the conditioned fluid to the building spaces is configured with controls to adjust fluid flow. For example, an air duct may be configured with a controllable damper that is capable of opening and closing to control the flow of air to a space within the building. Similarly, piping may be configured with a controllable valve that is capable of opening and closing to control the flow of liquid or steam to a space within the building.
A system having HVAC zone control generally requires the use of a zone controller to receive the signals from the various thermostats, control the operation of the heating or cooling device, and control the distribution of the conditioned fluid through the ductwork or piping. The zone controller typically comprises electronic circuitry for evaluating the heating or cooling needs of the various zones of the building and for determining an appropriate control of the heating or cooling device and the dampers or valves. While this control may be as simple as turning on the heating or cooling device and opening the damper or valve for a particular zone any time the thermostat from that zone calls for space conditioning, often times more complex control strategies are desired. For example, U.S. Pat. No. 5,024,265, incorporated in its entirety herein by reference, describes a zone control system having means for determining the zone of greatest demand and for synchronizing the start of the control signal for other zones to coincide with the start of the control signal for the zone of greatest demand. One advantage of this arrangement is that it may prevent overcycling of the heating or cooling device. Even relatively simple zone control schemes require substantial electronic circuitry to implement. Where more complex control strategies are used, even greater amounts of electronic circuitry are required. Regardless of the zone controller operating strategy used, zone controller electronic circuitry generally require a plurality of electronic components, such as wire receptacles, logic devices, relays, resistors, power supplies, and other electronic components for proper operation. The number of these electronic components tends to increase with increasing functionality and capacity of the zone controller.
There is a need for improved zone controllers.
The invention relates to an HVAC zoning control panel. The zoning control panel includes an electronic board having a plurality of electrical components attached to the board. The electrical components are constructed and arranged to receive a plurality of signals from a plurality of thermostats and to transmit a plurality of signals to a plurality of air control devices for controlling airflow in ducts. The electrical components include a first grouping of electrical components that includes components that are not accessed to perform either installation or operation functions, a second grouping of electrical components that includes components that are accessed to perform installation functions, and a third grouping of electrical components that includes components that are accessed to perform operation functions. The zoning control panel also includes a first board cover that is configured to prevent access to the first grouping of electrical components, and also a second board cover that is configured to selectively prevent access to the second grouping of electrical components but not the third grouping of electrical components.
Another aspect of the invention relates to an HVAC zoning control panel having a board and a plurality of electronic components attached to the board. The electronic components include components configured to receive a plurality of signals from a plurality of thermostats, components configured to transmit a plurality of signals to a plurality of dampers within air ducts; components configured to transmit signals to a conditioning unit for modifying the temperature of air within air ducts, components configured to provide an interface for selecting operating parameters, components configured to provide an indication of a condition, and a microprocessor configured to control the transmission of signals to the dampers and conditioning unit in response to the signals received from the thermostats and parameters selected through the interface. The electronic components of the HVAC zoning control panel also include a first grouping of electronic components that includes components that are not accessed to perform either installation or operation functions, a second grouping of electronic components that includes components that are accessed to perform installation functions, and a third grouping of electronic components that includes components that are accessed to perform operation functions. The HVAC zoning panel further includes a first board cover that is configured to prevent access to the first grouping of electronic components, and a second board cover that is configured to selectively prevent access to the second grouping of electronic components but not the third grouping of electronic components
The invention may be more completely understood by considering the detailed description of various embodiments of the invention that follows in connection with the accompanying drawings.
While the invention may be modified in many ways, specifics have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives following within the scope and spirit of the invention as defined by the claims. In the drawings and in the following description, like numbers will reference like parts.
A zone controller must ultimately be installed in a building and operated in order to be useful. However, despite the fact that many installers have training in the installation of HVAC components, the task of installing a zone controller can be difficult. This difficulty is related in part to the complexity of the zone controller itself. Because the configuration of the HVAC equipment can vary considerably from one building to the next, zone controllers are often provided with the capability to adapt to a wide variety of equipment configurations. However, this adaptability often requires that the installer make a number of selections or adjustments to the zone controller itself. The need for adaptability also often increases the complexity of the controller and the number of electronic components that are part of the zone controller. The end result is that the zone controller may have a large number of electronic components, some of which the installer is required to manipulate and some of which are not intended to be manipulated. The complexity of the zone controller may cause the installer to become confused regarding the proper installation procedures, despite having training in the operation and installation of HVAC equipment. This confusion may result in increased installation labor time, and therefore installation cost, or even improper installation and improper operation of the zone controller. Furthermore, there is a risk that some of the electronic components within the zone controller will be inadvertently damaged during the installation due to the fact that the sheer number of electronic components within the zone controller increases the probability of inadvertently making contact with an electronic component and causing damage. Also, the proximity of electronic components that require manipulation to those that do not require manipulation increases the chance that an electronic component will be damaged. There is also a safety risk to the installer if components are exposed within the zone controller that have an electrical potential.
Once a zone controller has been installed and made operational, the homeowner or building occupant may need to interface with it. A zone controller may be configured to provide status information so that an owner or occupant can determine whether the zone controller is working properly. A zone controller may also provide certain functions that are intended to be manipulated by the building owner or occupant. For example, a zone controller may include a switch that is selected when the building is to be unoccupied for an extended period. This switch could be used is to revert to a single thermostat type operating mode, where the entire building is controlled by only a single thermostat. This allows the owner or occupant to set only one thermostat back to an energy saving setting while the building is unoccupied, rather than having to change the settings of all thermostats in the building. However, owners or occupants are often not trained in the operation of complicated HVAC equipment and zone controllers. Particularly where a zone controller has a large number of electronic components, a building owner or occupant may be confused by the complexity of electronic components within the zone controller and may not accomplish their desired task or may inadvertently change a setting of the zone controller that will negatively affect its performance.
Alternatively, conditioning unit 32 may be a boiler that increases the temperature of a liquid or steam. In this case, fluid is transmitted through piping 34, 36, 38, where the flow of fluid is controlled by valves 40, 42, 44. The principles of operation discussed herein are equally applicable to an air-based system or a liquid- or steam-based system. For ease of description, we will describe the invention with respect to an air-based system, however, it should be understood that all descriptions are equally applicable to a liquid- or steam-based system.
A variety of control strategies for zone controller 46 are usable. In general, however, zone controller 46 is configured to open and close dampers 40, 42, 44, in response to signals from thermostats 26, 28, 30, respectively, and to operate conditioning unit 32. For example, if zone controller 46 senses that thermostat 26 is calling for heat because the temperature in zone 20 has fallen below a preset level, then zone controller 46 signals conditioning unit 32 to turn on and signals damper 40 to be in an open position. Heated air from conditioning unit 32 will then travel through duct 34, through damper 40, and into zone 20, thereby tending to increase the temperature within zone 20. If at the same time thermostats 28, 30 in zones 22, 24 do not call for heat, dampers 42, 44 will be closed and heated air will not travel through ducts 36, 38 into zones 22, 24. The operation of HVAC system 10 in response to other thermostat signals from other zones and other combinations of zones is similar. HVAC system 10 may include other sensing devices and other sources of input to zone controller 46, as well as other actuating devices and other device that are controlled by zone controller 46.
A schematic of electronic components of one embodiment of a zone controller 70 is shown in
Signals received at thermostat terminals 100, 102, 104, 106 are transmitted to an input processing component 108 and further to a microprocessor 110. Microprocessor 110 is configured to receive signals from sensor terminal 112. Sensor terminal 112 may be configured to receive signals from sensors such as an outdoor air temperature sensor and a discharge air temperature sensor. Other sensors are usable. The nature and construction of these sensors are known to those of skill in the art. A power input 114 is provided for connection to a power supply transformer. Microprocessor 110 is further configured to transmit signals to a driver 116, which in turn transmits signals to a plurality of damper terminals 118, 120, 122, 124. Each of damper terminals 118, 120, 122, 124 is configured to receive wires that are used to transmit a signal to a damper to control the position of the damper. Microprocessor 110 is also configured to transmit signals to an equipment terminal 126. Equipment terminal 126 is configured to receive wires that are used to transmit signals to HVAC equipment, such as a furnace, boiler, air conditioner, or heat pump, to control the operation of the HVAC equipment. An interface 128 is provided that is in communication with microprocessor 110 and is used to input various parameters and make various selections to affect the operation of the zone controller 70. Interface 128 may take a number of forms, such as a plurality of dip switches, dials, and potentiometers and other electronic components, an LCD screen and buttons, or a plurality of film-style switches. Interface 128 is particularly adapted for use during the installation process in order to configure the zone controller 70 to operate properly with the specific HVAC equipment that is present. Operation module 130 is intended for use during the operation of the zone controller 70 for determining the status of the zone controller 70 and for providing operation inputs. For example, operation module 130 may be configured to provide indicator lights that indicate the status of an aspect of zone controller 70, and may be configured to provide switches for setting a mode of operation. Operation module 130 is in communication with microprocessor 110. Each of the electrical components of zone controller 46 is attached to an electronic board 132.
As stated above, it is desired that the zone controller 70 be configured to allow the installer to make the necessary electrical connections and settings so that the zone controller will function properly in the particular application in which it is being used. The zone controller is also desirably configured to minimize the confusion of the installer that is possible with the large number of electrical components being present within the zone controller. It is also desired that any functions or interfaces directed toward the building owner or occupant also be presented in a manner that prevents confusion and prevents inappropriate modification of the settings of the zone controller.
The zone controller 70 of the present invention is directed toward satisfying these objectives. An exploded view of components of a zone controller 70 is shown in
A perspective view of components of one embodiment of a zone controller 70 constructed according to principles of the present invention is shown in
Zone controller 70 has a first cover 94 configured to cover the first grouping of electronic components 84.
First cover 94 does not cover the second grouping of electronic components 86, thereby allowing the installer to access the electronic components that are related to the installation but not the components that are not related to the installation. Alternatively, first cover 94 provides an opening or other means of accessing the second grouping of electronic components 86. Cover 94 may cover or partially cover any electronic components within the third grouping of electronic components 88, but generally does not prevent the third grouping components 88 from being accessed. For example, where the third grouping 88 includes an LED indicator 90, cover 94 has a transparent or translucent portion for allowing the LED indicator 90 to be perceived, in certain embodiments. Also, where the third grouping includes a switch 92, cover 94 partially covers a portion of switch 92, in some embodiments, so long as switch 92 can be actuated as intended.
Zone controller 70 also has a second cover 96 configured to cover the second grouping of electronic components 86.
Second cover 96 covers the second grouping of electronic components 86, thereby preventing a building owner or occupant from accessing electronic components that should not be accessed or modified without adequate training. Although second cover 96 can be removed if needed, the act of removing the cover provides an indication to an owner or occupant that he or she is accessing components that are intended for more complex functions and are not generally intended for use by people without sufficient training. Second cover 96 also simplifies the presentation of the zone controller 70 to provide a more attractive and orderly appearance. Many embodiments of second cover 96 are usable. In the particular embodiment of
An alternative embodiment of a zone controller 170 is shown in
The present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification. The claims are intended to cover such modifications and devices.
The above specification provides a complete description of the structure and use of the invention. Since many of the embodiments of the invention can be made without parting from the spirit and scope of the invention, the invention resides in the claims.
