Field of the Invention

The present invention relates to the field of air conditioning. More particularly, the invention relates to a multi-speed air-flow air conditioning system.

Background of the Invention

A multi-speed fan motor that is able to operate at different speeds, for example a three-speed fan motor at a range of 700-1200 rpm, for control of the flow of conditioned air throughout a given space to be conditioned, whether for example a living space or a working space, and therefore of the temperature of the space, regulates the air flow according to the system demand, consumes significantly less electricity than a constant-speed fan motor and contributes to user comfort. Since the multi-speed fan motor operates continuously, the air conditioning system operates with less fluctuations in temperature, sound and air flow than one employing a constant-speed fan motor. The speed of a multi-speed fan motor is automatically regulated in response to one or more sensed values associated with the air conditioning system.

A fan, driven by a multi-speed motor, is well suited for delivering conditioned air to distant regions of the given space, with changing loads and air flow demands through a duct system. When a multi speed fan motor operates in conjunction with a central air conditioning system configured with a plurality of ducts such that each duct delivers the conditioned air to a different room, a damper installed in each duct is able to further adjust the air flow so that the temperature in each room is able to be different.

In one approach, a differential pressure sensor senses a pressure drop across the damper, and the speed of the multi-speed fan motor is regulated in response to the sensed differential pressure. However, a differential pressure sensor has to be accurate and therefore expensive in order to enable reliable regulation of the motor. Additionally, the differential pressure sensor is liable to be clogged by foreign material over the course of time, reducing the precision of the pressure measurement and the reliability of the air conditioning system. It is an object of the present invention to provide an air conditioning system comprising a regulated multi-speed fan motor for delivering conditioned air through a duct, including a duct system, which is considerably more reliable than that of the prior art.

It is an additional object of the present invention to provide an air conditioning system comprising a multi-speed fan motor for delivering conditioned air through a duct, including a duct system, which is regulated by means of a considerably more inexpensive control system than that of the prior art.

Other objects and advantages of the invention will become apparent as the description proceeds.

Summary of the Invention

A multi-speed air-flow air conditioning system, comprising an indoor unit configured with a blower fan, a heat exchanger, and a duct through which air directed from said blower fan and across said heat exchanger is discharged into a room to be conditioned, wherein an adjustable damper for regulating flow of air is fitted within an interior of said duct, and wherein operation of a controllable multi-speed component of the air conditioning system is automatically regulated in response to a degree of opening of said damper.

In one aspect, the system further comprises controller means, such as a damper controller in data communication with a system controller, configured to determine the degree of opening of the damper and to transmit data representative of the degree of damper opening to a driver of the controllable component, whereby to regulate the speed of the controllable component.

In one aspect, the indoor unit is the indoor unit of a central air conditioning system configured with an air distribution unit from which the conditioned air is divided to the interior of each of a plurality of ducts adapted to direct the conditioned air to a corresponding room and fitted with a corresponding damper.

In one aspect, the controller means is operable to determine an overall restriction caused by each of the corresponding dampers relative to a total maximum opening of all of the plurality of ducts and to transmit data representative of the overall restriction to the driver of the controllable component, whereby to regulate the speed of the controllable component. In one aspect, the system further comprises one or more sensors in data communication with the controller means for detecting air conditioning values of importance that are associated with the air conditioning system

In one aspect, one of the one or more sensors is a temperature sensor for detecting air temperature within the corresponding room, wherein operation of the controllable component is additionally automatically regulated in response to the detected air temperature within the corresponding room. The temperature sensor may be mounted at a room-facing end of the duct, or within the corresponding room, such as housed within an input device which is located within the corresponding room.

In one aspect, one of the one or more sensors is an occupancy sensor for determining whether the corresponding room is unoccupied, the corresponding damper becoming automatically closed and operation of the controllable component being automatically reduced in conjunction with the controller means following determination that the corresponding room is unoccupied. The controllable component becomes automatically deactivated if it is determined that all rooms corresponding to the plurality of ducts are unoccupied.

In one aspect, the controllable component is a multi-speed fan motor for driving the blower fan.

In one aspect, the controllable component is a multi-speed compressor.

In one aspect, the multi-speed controllable component is a variable-speed controllable component.

In one aspect, the system controller is adapted to control operation of the indoor unit of the air conditioning system using data which is representative of the degree of damper opening.

In one aspect, the system controller is additionally adapted to control operation of an outdoor unit of the air conditioning system using data which is representative of the degree of damper opening. For example, the system controller is operable to control frequency of a variable-speed compressor of the outdoor unit. Brief Description of the Drawings

In the drawings:

- Fig. 1 is a schematic illustration of an embodiment of an air conditioning system configured with a controlled fan motor;

- Fig. 2 is a schematic illustration of another embodiment of an air conditioning system configured with a controlled compressor; and

- Fig. 3 is a schematic illustration of a multi-duct air conditioning system configured with both a controlled fan motor and a controlled compressor.

Detailed Description of the Invention

The air flow through a room is regulated in response to the degree of damper opening of an adjustable damper that is mounted in a duct of a multi-speed air-flow air conditioning system. The air conditioning system is suitable for operating in conjunction with a single duct in which is mounted the adjustable damper, and also for operating in conjunction with a central air conditioning system having a plurality of ducts in each of which is mounted the adjustable damper. Data related to the degree of damper opening is transmitted to a multi-speed controllable component of an air conditioning system, and, in response, the operation of the controllable component is automatically adjusted. The controllable component, such as a multi-speed fan motor or compressor, may operate at any one of discrete settings, or may be a variable-speed controllable component whose speed is able to be differentially regulated by very small differences in speed, for example a fan motor operating in a speed range of 250-1500 rpm. This air flow regulation scheme significantly reduces energy consumption and noise emission relative to prior art practices.

The degree of damper opening has been used in the prior art to regulate room temperature. When a temperature difference between a requested temperature and a measured temperature has been determined, the damper has been commanded by the prior art control system to change its degree of opening and to facilitate attainment of the requested room temperature. If, for example, the measured temperature in a cooling mode is less than the requested temperature, the damper is commanded to reduce its degree of opening, causing a reduced air flow to be introduced into the room so that the room temperature will increase. However, since a constant-speed fan motor has been used in the prior art, some of the air flow of high static pressure will be restricted by the damper when its degree of opening is abruptly reduced, resulting in an annoying increase in the noise level while the restricted air flow impinges on the damper. Restriction of the air flow also involves unnecessary energy wastage due to the unused air.

The energy conserving air conditioning system of the present invention may comprise a damper related control unit that may constitute an add-on in order to upgrade an existing air conditioning system. Alternatively, a dedicated factory-designed air conditioning system incorporates the damper related control unit.

Fig. 1 schematically illustrates a multi-speed air-flow air conditioning system 1, according to an embodiment. Air conditioning system 1 is of the split type, wherein the outdoor unit comprises a compressor and heat exchanger, and the indoor unit comprises a multi-speed fan motor 6 and a heat exchanger 7, which functions as an evaporator in a cooling mode and as a condenser in a heating mode. The blower fan 9, which is driven by motor 6, draws hot room air in a cooling mode via an inlet port 2 over the evaporator coils to cause cold liquid refrigerant exiting an expansion valve to absorb heat from the hot room air and to become heated and vaporize. The vaporized refrigerant is delivered to the compressor to repeat the refrigeration cycle.

Blower fan 9 delivers the conditioned air via duct 11 to a room of the building in which air conditioning system 1 is mounted. An adjustable damper 12 for regulating the flow of air is fitted within the interior of duct 11, generally proximate to the room-facing end 14 thereof. Damper 12 is generally pivotally mounted onto sides of duct 11 by a pivot pin, which is rotatably driven a predetermined angular distance by damper motor 3 or by any other suitable actuator that is able to pivot the damper to a desired degree of damper opening. Damper motor 3 is electrically connected to damper motor driver circuitry 4, which may comprise circuitry for identifying the damper and the degree of damper opening, as well as for communicating with controller means 5. Damper motor 3 may be any suitable motor well known to those skilled in the art, such as a DC motor, a step motor or an AC gear motor.

The degree or percentage of opening of damper 12 may be unchangeable during operation of air conditioning system 1, being set by a user. Alternatively, the degree of damper opening may be adjustable in response to sensed room values. Damper motor driver circuitry 4 is adapted to determine the degree of damper opening through the instantaneous rotational position of the rotor of damper motor 3 relative to a predetermined starting position, or from any other suitable electric actuator configured to pivot damper 12. In order to determine the rotational position of the rotor, and therefore the degree of damper opening, a Hall effect sensor may be used to provide signals representative of the rotor position. Alternatively, the rotor position of a brushless DC step motor may be obtained by detecting back-EMF data related to the magnetic flux. For example, the commutation instants may be identified by detecting the zero crossing point (ZCP) of a nonconducting phase of the back-EMF. Since data needed to control the fan motor speed is acquired electronically, the need for a pressure sensor which is mounted within a duct wall as practiced heretofore in the prior art and is susceptible to clogging is obviated.

Damper motor driver circuitry 4 is additionally configured to identify the damper 12 that it is intended to control, as well as to obtain the size of the duct 11 within which damper 12 is mounted, for example whether it is an 8-inch, 10-inch or 12-inch duct. Data related to the size of the duct 11 is defined by means of a jumper connected to a processor of damper motor driver circuitry 4, and the data output of the processor is transmitted to controller means 5 by a wired or a wireless connection. The efficient operation of multi-speed fan motor 6 to deliver an optimal air flow rate through duct 11 is contingent upon knowing the duct size.

Controller means 5 is in data communication with damper motor driver circuitry 4 and with a driver 8 of multi-speed fan motor 6. Controller means 5 transmits data indicative of the duct size and of the current degree of damper opening to driver 8, and the latter commands operation of multi-speed fan motor 6 in accordance with the data received from controller means 5. Thus multi-speed fan motor 6 is advantageously controlled to operate at a reduced speed in response to the degree of opening of the damper, to ensure reduced electricity consumption when damper 12 is partially or completely closed and to maintain quiet operation since a reduced air flow will be restricted.

Controller means 5 may comprise two controllers. A first controller acquires data indicative of the current degree of damper opening and transmits the same to the second controller, which is a system controller adapted to control operation of the entire air conditioning system. The speed of multi-speed fan motor 6 is automatically regulated in response to the damper opening data transmitted to driver 8 by the system controller. The system controller may additionally transmit data to the driver of an inverter-type variable-speed compressor to command operation of the variable-speed compressor in response to the degree of opening of the damper, to achieve additional reduction in energy consumption. The first controller and its connection to the damper circuitry and to the second controller may constitute a damper related control unit functioning as an add-on unit.

Alternatively, controller means 5 may be a single dedicated controller that functions as both a damper controller and a system controller.

In another embodiment illustrated in Fig. 2, a split-type air conditioning system 10 is configured to automatically regulate a multi-speed compressor 16 in response to the degree of opening of adjustable damper 12 fitted within the interior of duct 11, so that energy consumption will be significantly reduced.

Controller means 5 is in data communication with damper motor driver circuitry 4 and with a driver 17 of multi-speed compressor 16. Controller means 5 transmits data indicative of the duct size and of the current degree of damper opening to driver 17, and the latter commands operation of multispeed compressor 16 in accordance with the data received from controller means 5. Thus multispeed compressor 16 is advantageously controlled to operate at a reduced speed in response to the degree of opening of the damper, to ensure reduced electricity consumption when damper 12 is partially or completely closed.

Air conditioning system 10 is similar to air conditioning system 1 of Fig. 1, but fan motor 13 for driving blower fan 9 of the inside unit may be a constant-speed fan motor. Alternatively, fan motor 13 may be a multi-speed fan motor, and controller means 5 may also cause the speed of fan motor 13 to be regulated in response to the degree of opening of damper 12, in addition to causing the speed of compressor 16 to be regulated in response to the degree of opening of the damper.

Fig. 3 schematically illustrates variable air-flow central air conditioning system 20, according to another embodiment. Air conditioning system 20 is also of the split type, wherein the outdoor unit 21 is configured with a variable-speed compressor 24, and the indoor unit 15 comprises a central conditioned air distribution unit 22, a variable-speed fan motor 19 for driving fan 27, and a heat exchanger. The heat exchanger functions as an evaporator in the cooling mode and as a condenser in the heating mode. Variable-speed compressor 24 may be of the DC twin rotary type having two compression chambers to produce a phase difference of 180° in their mutual compression timing while able to achieve a large range in rotational speed at high efficiency and low noise at any speed in response to the given thermal load within a room, or alternatively may be of any other variable-speed type.

Variable-speed fan motor 19, generally a DC motor, for example having up to seven distinct speeds and controlled using pulse width modulation (PWM), continuous voltage such as 0-10V, or continuous current control such as 4-20 mA, may be a PERFECTSPEED ^® motor manufactured by Nidec Motor Corp, St. Louis, MO, USA, which is configured with electronic commutation.

The indoor air is conditioned when flowing across the heat exchanger. The conditioned air exits air distribution unit 22, which is connected to the casing of indoor unit 15, via an outlet port from which the conditioned air is divided and distributed to the interior of each of a plurality of flexible ducts 18, for example flexible ducts 18a-c, which are adapted to direct the conditioned air to a corresponding room. A flexible duct, which generally has an outer polyethylene protective liner, an intermediate fiberglass insulation layer, and an interior polyethylene liner in which is embedded round metal wire to main the shape of the duct, is advantageous in that it can be easily installed in regions where the ducts needs to be bent in order to avoid obstacles. It will be appreciated that a rigid duct may be employed in lieu of a flexible duct.

An adjustable damper 23 for regulating the flow of air is fitted within the interior of each flexible duct 18, proximate to the room-facing end thereof. Damper 23 may be continuously set to a user-selected degree of opening. Alternatively, damper 23 is controllably adjusted to change its degree of opening at a predetermined time, for example to a third or a two-thirds degree of opening. Damper controller 35 is in data communication with the driver of each damper 23 to receive data relating to the degree of damper opening and to the duct size, and is additionally in data communication with system controller 40. In response to receiving data relating to the degree of damper opening at each duct and the dimensions of each duct, system controller 40 determines an overall restriction caused by the dampers relative to the total maximum opening of all ducts and commands variable-speed fan motor 19 to adjust its speed relative to the speed that would be required if all dampers were completely opened. The local restriction of a single damper is defined as the percentage of opening in the corresponding duct that is occluded by the projection of the damper, and the overall restriction is the weighted average of each local restriction, when taking into account different opening sizes of the ducts. The noise level associated with the impingement of the restricted air on damper 23 relative to prior art practice is advantageously reduced as a result of the reduced airflow.

A user interacting with a local remote control device 31, for example local remote control devices 31a-c associated with the damper of ducts 18a-c, respectively, is able to individually close or adjust the degree of opening of the corresponding damper 23. The operating speed of variable-speed fan motor 19 is accordingly regulated in response to the degree of opening of each damper.

Control features associated with system controller 40, for example the different speed levels by which variable-speed fan motor 19 is controlled or a time for activating air conditioning system 10, may be set by central input device 42, such as a touch screen, or by a central remote control device 43. These control features are well suited for implementation by a home automation network. A WiFi module 47 in data communication with system controller 40, and possibly with an application running on a smartphone of a user, may also be used for remotely setting control features.

Damper controller 35 in data communication with system controller 40 may be part of an add-on module configured to upgrade an existing air conditioning system.

In another embodiment, one or more air conditioning sensors 26 in data communication with damper controller 35 for detecting air conditioning values of importance may be associated with each room to be conditioned, and may be influential in the flow of air into the room. Thus sensors 26a-c may be mounted on ducts 18a-c, respectively. An air conditioning sensor 26 may be mounted at the room-facing end of each flexible duct 18, as shown, or may be mounted in the room. A room mounted air conditioning sensor 26 may be housed in a local remote control device 31, central input device 42, or central remote control device 43. An air conditioning sensor 26 may be used for detecting room temperature, and may be based on a thermostat or an equivalent thereof, or comprise an infrared thermometer based on a distance to a measurement surface and on a diameter of a temperature measurement area. Alternatively, an air conditioning sensor 26 may be an occupancy sensor which is configured as a photoeye for determining the presence of a human with a corresponding room and which comprises an IR receiver, an IR transmitter and LED indicators.

When an occupancy sensor determines that a room is unoccupied, or alternatively when information regarding the intended unoccupancy of a room is input to system controller 40 by input device 42, the corresponding damper becomes automatically closed in conjunction with damper controller 35, to reduce the volumetric flow of air through air distribution unit 22, allowing variable-speed fan motor 19 to operate at a lower speed. If it is determined that all rooms are unoccupied, variable- speed fan motor 19 will become deactivated.

The degree of a damper opening may also be automatically adjusted in response to the temperature detected by the corresponding air conditioning sensor. For example, the degree of a damper opening may be automatically increased if the temperature differential between a set temperature, for example set by means of a remote control device, and a detected temperature within return air, or alternatively with a room, is greater than a predetermined value. When the degree of a damper opening is automatically increased, variable-speed fan motor 19 is caused to operate at a higher speed. The volumetric flow of air through air distribution unit 22 is correspondingly increased, while the actual volumetric flow of air through each duct is dependent upon on the individual degree of a damper opening at each duct.

The remote control device may be a wired device or a wireless device. In addition to selecting a set temperature and a selected degree of damper opening, the remote control device may be used for selecting a mode of operation, whether a constant damper angle mode or an adjustable damper angle mode.

Table 1 shows an exemplary variation in the speed of variable-speed fan motor 19 as a function of both the current weighted degree of damper opening related to all ducts of the air conditioning system and the temperature difference between a set temperature and a detected temperature of the return air.

Table 1

The temperature in three different rooms, for example, can be regulated to a different temperature with multi-zone control by different degrees of damper opening. Since the mass flow rate of cooling air introduced into a room by a duct is controlled by the degree of damper opening, the rate of heat transfer to the room provided by the cooling air and therefore the room temperature that is achievable are also controllable.

The regulation in speed of variable-speed fan motor 19 may be controlled by a weighted average of the temperature difference, for each duct, between the set temperature and the temperature of the return air.

System controller 40 is also in data communication with variable-speed compressor 24. Controller 40 commands the inverter of variable-speed compressor 24 to change its maximum frequency in order to accommodate the current degree of damper opening of the plurality of dampers and to operate more efficiently.

Table 2 shows an exemplary variation in the speed of variable-speed fan motor 19 as well as in the maximum frequency of the variable-speed compressor 24 as a function of both the current weighted degree of damper opening related to all ducts of the air conditioning system and the temperature difference between a set temperature and a detected temperature of the return air.

Table 2

In one embodiment, a two-step control sequence may be employed. In a first step, damper controller 35 controls the degree of damper opening in response to a temperature differential between the set temperature and the presently detected room temperature. The degree of damper opening may be room-specific. In a second step, system controller 40 controls operation of fan motor 19 and of compressor 24 in response to a temperature differential between the set temperature and the return air temperature, based on the current weighted degree of damper opening related to all ducts of the air conditioning system.

While some embodiments of the invention have been described by way of illustration, it will be apparent that the invention can be carried out with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the scope of persons skilled in the art, without exceeding the scope of the claims.