Patent ID: 12215889

The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the teaching of the present specification and are not intended to limit the scope of what is taught in any way.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Various apparatuses, methods and compositions are described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover apparatuses and methods that differ from those described below. The claimed inventions are not limited to apparatuses, methods and compositions having all of the features of any one apparatus, method or composition described below or to features common to multiple or all of the apparatuses, methods or compositions described below. It is possible that an apparatus, method or composition described below is not an embodiment of any claimed invention. Any invention disclosed in an apparatus, method or composition described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicant(s), inventor(s) and/or owner(s) do not intend to abandon, disclaim, or dedicate to the public any such invention by its disclosure in this document.

The terms “an embodiment,” “embodiment,” “embodiments,” “the embodiment,” “the embodiments,” “one or more embodiments,” “some embodiments,” and “one embodiment” mean “one or more (but not all) embodiments of the present invention(s),” unless expressly specified otherwise.

The terms “including,” “comprising” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. A listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a,” “an” and “the” mean “one or more,” unless expressly specified otherwise.

As used herein and in the claims, two or more parts are said to be “coupled”, “connected”, “attached”, or “fastened” where the parts are joined or operate together either directly or indirectly (i.e., through one or more intermediate parts), so long as a link occurs. As used herein and in the claims, two or more parts are said to be “directly coupled”, “directly connected”, “directly attached”, or “directly fastened” where the parts are connected in physical contact with each other. None of the terms “coupled”, “connected”, “attached”, and “fastened” distinguish the manner in which two or more parts are joined together.

Furthermore, it will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the example embodiments described herein. However, it will be understood by those of ordinary skill in the art that the example embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the example embodiments described herein. Also, the description is not to be considered as limiting the scope of the example embodiments described herein.

As used herein, the wording “and/or” is intended to represent an inclusive—or. That is, “X and/or Y” is intended to mean X or Y or both, for example. As a further example, “X, Y, and/or Z” is intended to mean X or Y or Z or any combination thereof.

Fan Coil

The following is a general description of a fan coil having a humidification unit and other features set out herein. The following description contains various features which may be used individually or in any combination or sub-combination.

Referring toFIGS.1and2, there is shown an example fan coil100, in accordance with an embodiment. In the illustrated example, the fan coil100includes a housing104including a front face108defining a return air inlet port112and a treated air outlet port116. The fan coil100is operable to receive air from the inlet112, heat or cool the air introduced from the inlet112and, as selected, humidify the air, and discharge the treated air through the outlet116into a room.

The example shown includes a housing104that is substantially cuboid (i.e. box-shaped). An advantage of this design is that it provides an efficient and convenient form factor for applications where the fan coil100is recessed into a flat wall. However, in alternative embodiments, the fan coil housing104can have any size and shape best suited for the intended application.

In the example shown, the fan coil inlet112and outlet116are formed in the front face108of the fan coil housing104. This design provides an efficient self-contained apparatus that can be easily accommodated into a room design. However, in alternative embodiments, the fan coil inlet112, the fan coil outlet116, or both may be located remotely from the fan coil housing104. For example, the fan coil outlet116may be fluidly connected to the fan coil housing104by one or more air flow conduits to allow the fan coil100to service one or more rooms remote from the fan coil100(e.g., via ducting built into a wall or ceiling of a building). In some embodiments, fan coil100may include a plurality of fan coil air inlets112, a plurality of fan coil air outlets116, or a plurality of fan coil air inlets112and a plurality of fan coil air outlets116. For example, fan coil100may include a plurality of fan coil air outlets116directed to different rooms. This allows one fan coil100to service several rooms.

It will be appreciated that the fan coil100may be of any design known in the art and may use any flow path, and any heating and air conditioning units known in the heating and cooling arts. In the example shown inFIG.2, the fan coil100includes an air blower132and an air flow path136which extends from the fan coil air inlet112to the fan coil air outlet116. In the illustrated example, the air flow path136includes a heating zone148between an upstream first portion144of the fan coil air flow path136, and a downstream second portion152of the fan coil air flow path136.

The heating zone148can include any air heating device capable of heating the air moving downstream across the heating zone148. In the illustrated example, the air heating device is provided by a heat exchange unit160in thermal communication with a heat source. As shown, the heat source is provided by heated water circulated through supply and return pipes162. In other embodiments, the air heating device may be provided by resistive heating elements, a natural gas burner, or the like. In some embodiments, the air heating device includes a heat recovery ventilator (HRV) or an energy recovery ventilator (ERV) that receives heat, or heat and humidity, from exhausted room air for use, e.g., in treating fresh air introduced into the unit from the outside.

Still referring toFIGS.1and2, the fan coil100is shown including a humidification unit164in flow communication with the air flow path136. The humidification unit164is operable to humidify air in the fan coil air flow path136so that humidified air is discharged from the fan coil air outlet116. When air is heated in the heating zone148, the relative humidity of the air may decrease. The humidity added by the humidification unit164can help to maintain or increase the relative humidity of the air after heating.

In the illustrated example, the humidification unit164is positioned in and discharges water mist into the air flow path136downstream of the heating zone148. An advantage of discharging the water mist downstream of the heating zone148is that the low relative humidity of the heated air allows the water mist to be more efficiently absorbed. As a result, less water mist generation may be required and less water mist may accumulate in the fan coil which may result in rusting of the apparatus or leaking of water from the fan coil apparatus. In turn, the humidification unit164may consume less power by activating less frequently, activating at a lower power setting, or by including a less powerful water mist production member. Also, less water may be consumed by the humidification unit164because less water is lost. In alternate embodiments, the humidification unit164may be positioned upstream the heating zone148. An advantage of this design is that cooler air moves through the humidification unit164, which makes microorganisms, mold, and the like less likely to cultivate inside the humidification unit164.

In some embodiments, an air regulating device may be operably connected to fan coil apparatus100. The air regulating device may operate as a thermostat and/or a hygrostat, capable of sensing air temperature and/or air humidity, and signaling the fan coil100to generate heated, cooled and/or humidified air in order to maintain the room air at a set temperature and/or humidity. For example, the air regulating device may be programmed to maintain the room air at 21° C. and 40% relative humidity for comfortable human occupancy. The air regulating device can be any thermostat and/or hygrostat device known in the art. For example, the air regulating device may include inputs for user interaction (e.g. buttons to enter a set air temperature and relative humidity), and an optional display (e.g. to display the current air temperature and relative humidity).

Humidification Unit

The following is a general description of a humidification unit that may be used with a fan coil. In accordance with this aspect, the humidification unit comprises a boiler to produce a mist from liquid water. The following description contains various features of a humidification unit which may be used individually or in any combination or sub-combination.

Referring toFIGS.3to8, there is shown an example humidification unit164, in accordance with an embodiment. In the illustrated example, the humidification unit164includes a water inlet202and a mist outlet204. The humidification unit164is operable to receive liquid water from the inlet202, generate water vapor (i.e., mist) from the liquid water, and discharge water mist through the mist outlet204. In various embodiments, the humidification unit164can be positioned within the fan coil100so that when the humidification unit164is actuated, water can be provided to the air in the air flow path136. In the illustrated example, the humidification unit164includes mounting members242for fixing the humidification unit164to the fan coil100. Any mounting member may be used so as to position the humidification unit164at any desired location in fan coil100.

As exemplified inFIGS.3,5, and6, the humidification unit164may include a boiler206for generating water vapor. The boiler206is operable to store liquid water and heat the stored water using a heating element212to generate water vapor. In various embodiments, electrical power can be supplied to the heating element212to heat the boiler206, thereby heating the water stored in the boiler206. In the illustrated example, the heating element212is provided by a thick film resistor disposed on the exterior surface of the boiler206. An advantage of this design is that the temperature of the water can be more easily controlled as compared to an immersion heater. It should be appreciated that various embodiments are described herein with reference to the boiler206for ease of exposition. However, in alternate embodiments, the humidification unit164may include other mechanisms for generating water mist, such as an ultrasonic oscillator, an impeller, etc. It will also be appreciated that water may not be stored in boiler206but may only be introduced to boiler206when the boiler is actuated to produce mist. Accordingly, a valve or the like may be opened to introduce water into boiler before, as or after heating element212is actuated.

Boiler206may be mounted to fan coil100in any orientation. As exemplified inFIG.2, boiler206is oriented generally vertically. However, boiler206may be at any orientation to the vertical. Optionally, boiler is at a non-zero angle to the horizontal such that water may drain out of boiler206when boiler is not in use (e.g., heating element212is not energized).

In various embodiments, the boiler206can be filled and drained through the inlet202. As exemplified inFIG.7, the boiler206may receive liquid water from a first water line192and discharge liquid water into a second water line194. The first water line192may be fluidly coupled to a water supply, such as a municipal water line (e.g., a water line in an apartment or condominium) or a reservoir of water (e.g. water tank) external to fan coil apparatus100. The second water line194may be fluidly coupled to a water drain, such as a municipal sewage line or an effluent water storage.

In the illustrated example, an inlet valve196regulates the supply of liquid water to the boiler206and an outlet valve198regulates the discharge of liquid water from the boiler206. The inlet and outlet valves196and198each have an open position in which water is allowed to flow past the valve, and a closed position in which the valve prevents the flow of water. In other words, the inlet valve196can be actuated to control the ingress of water into the boiler206, and the outlet valve198can be actuated to control the egress of water from the boiler206. In some embodiments, the inlet and outlet valves196and198may have multiple open positions that define different rates of flow into and out of the boiler206. It will be appreciated that when valves196and198are closed and the heating element212is de-energized, water may be stored in boiled206.

The inlet and outlet valves196and198can be any valve capable of preventing the flow of water to or from the boiler206. For example, the inlet and outlet valves196and198may be an electrical valve (e.g. a solenoid valve). It should be appreciated that the inlet and outlet valves196and198may be positioned in various locations upstream or downstream the humidification unit164, such as on the water lines192and194, the water supply/drain, or between the water supply/drain and the water line192and194.

In the illustrated embodiment, the inlet202acts as both an inlet and an outlet for liquid water. However, it should be appreciated that the humidification unit164may include any number of liquid water inlets, liquid water outlets, and water mist outlets. In some embodiments, the humidification unit164may include a liquid water inlet and a separate liquid water outlet.

In some embodiments, the humidification unit164may include one or more baffles for restricting the flow of water and/or mist within the boiler206. In the example shown inFIGS.5and6, the humidification unit164includes first and second plates222and224, which define a boiling zone214, a splash zone226, and a steam zone228. As shown, the first and second plates222and224may be perforated to define a plurality of apertures. In the illustrated example, the first plate222is perforated over its entire surface, whereas the second plate224is only perforated near its perimeter. An advantage of this design is that the water vapor generated by the humidification unit164may flow in a serpentine path. However, it should be appreciated that various perforation patterns are possible.

The first and second plates222and224may inhibit liquid water from entering the mist outlet204. For example, turbulence in the liquid water during boiling may cause liquid water to splash within the boiling zone214. The first and second plates222and224may block the splashing water from entering the steam zone228and the water vapor outlet204, trapping the splashing water within the boiling zone214and the splash zone226. Additionally, the first and second plates224may prevent the discharge of water vapor through the water vapor outlet204that may otherwise condense or precipitate back into liquid water. The first and second plates222and224may trap some of the water vapor in the splash zone226and steam zone228, reducing the rate of discharge of water vapor the mist outlet204. This may provide time for the water mist to condense and precipitate back into liquid water prior to being discharged from the humidification unit164. This design may prevent or reduce water from accumulating in the fan coil100which may result in rusting of the fan coil100or leaking of water from the fan coil100.

In some embodiments, the humidification unit164may include one or more sensors for sensing the temperature of the humidification unit164. In the example shown inFIGS.3to5, the humidification unit164includes a thermal fuse252. The thermal fuse252is operable to interrupt the electrical power supplied to the heating element212when temperature of the humidification unit164exceeds a certain temperature. An advantage of this design is that the humidification unit164can be automatically deactivated when the temperature of the humidification unit164exceeds a safe operating temperature.

It will be appreciated that a humidification unit that comprises a boiler206may be used with any one or more aspects set out herein.

Control System

The following is a general description of a control system that may be used with a humidification unit. In accordance with this aspect, the control system is operable to actuate the humidification unit without being integrated into the control system of a fan coil100. Accordingly, a humidification unit may be easily retrofit into an existing fan coil100. The following description contains various features which may be used individually or in any combination or sub-combination. It will be appreciated that the control system may be used with any humidification unit useable in a fan coil100.

The control system comprises a controller172and a plurality of sensors. The sensors provide input to the controller172and enable the controller172to provide control signal to the humidification unit164based upon the input signals provided by the sensors.

For example, the sensors may include temperature sensors182,184(see for exampleFIG.2). Temperature sensors182,184may be positioned upstream and downstream from heating zone148. When the temperature sensed by downstream temperature sensor182is higher than the temperature sensed by upstream temperature sensor184, e.g., by 10° C., 20° C. or 30° C., the controller172may send a signal to energize heating element212. If valves196and198are provided, then controller may send a signal to close valve198(if it is open) and to open valve196(if it is closed). Accordingly, upon determining that the fan coil1000is in operation to heat a room, condominium or the like, the controller172may send signals to enable water to enter the boiler206(opening valve196and closing valve198) and energizing heating element212. Optionally, heating element212is energized a sufficient period of time after the signals are sent to valves196,198such that water is present in boiler206.

The sensors may optionally also include one or more humidity sensors186. See for exampleFIG.2. An advantage of providing a humidity sensor is that controller172may optionally control the operation of humidification unit206so as to provide a predetermined amount of mist to the air flow in the fan coil100based on, e.g., the temperature and humidity level in the air flow. Accordingly, even when temperature sensors182,184send signals indicative that fan coil100is in a heating mode, controller172may not send a signal to energize heating element212until humidity sensor186sends a signal indicative that the humidity level, e.g., in the air flow in fan coil100, optionally at allocation downstream of the heating zone, is below a particular level. Optionally, the control system includes an interface which allows a user to set a desired humidity level. Alternately, or in addition, the control system may have built in a level of humidity for different temperatures and accordingly the control system may actuate the heating element212when the humidity sensor186sends a signal indicative that the humidity level is below the present humidity level of the particular temperature that is sensed, e.g., by sensor182.

Optionally, the control system may also include a water level sensor.174(see for exampleFIG.8). The water level sensor may sense the level of water in humidification unit164(e.g., boiler206). Accordingly, even when temperature sensors182,184send signals indicative that fan coil100is in a heating mode, controller172may not send a signal to energize heating element212if water level sensor174sends a signal indicative that the water level in boiler206is too low and/or too high.

Accordingly, it will be appreciated that the controller172may include logic to receive and act upon control signals to start and stop water mist generation.

Referring toFIGS.2and8, there is shown an example controller172, in accordance with an embodiment. The controller172is operably connected with the humidification unit164so that the controller172can control the operation of the humidification unit164based on signals sent to the control by one or more sensors. In the illustrated example, the controller172is provided by a printed circuit board that includes various electronic components mounted thereon. However, it should be appreciated that the controller172may be any electronic device suitable for controlling the humidification unit164. For example, the controller172may include a processor, data storage, and a communication interface.

In accordance with this aspect, the controller172controls the activation of the humidification unit164to control the generation of water vapor. For example, if the humidification unit164comprises a boiler206, the controller172may control the activation of the boiler206. To this end, the controller172may regulate the supply of power to the humidification unit164to control the activation of the humidification unit164.

For example, if a water level sensor174is provided, then the controller172can power off the humidification unit164to immediately stop the generation of water vapor, even before the humidification unit164runs out of water (e.g., sensor174senses a low water level in boiler206). Shutting off the humidification unit164may prevent damage that may be caused by the humidification unit164operating without any or sufficient water present. For example, the humidification unit164may receive electrical power from an electrical line that is electrically coupled to a power supply, such as a municipal electrical grid (e.g., an electrical outlet or circuit breaker in an apartment or condominium), a power generator, or a power storage device (e.g. battery pack). The controller172may be positioned in a circuit between the electrical line and the power supply to regulate the supply of power from the power supply to the humidification unit164. Accordingly, the controller172may prevent the humidification unit164from receiving power from power supply to the humidification unit164or interrupt the delivery of power if the humidification unit164has a low water level, and allow the humidification unit164to receive power from power supply to activate the humidification unit164if the humidification unit164has a sufficient water level.

It will be appreciated that the controller172may regulate not only the activation of the humidification unit164but also the rate of water mist generation by the humidification unit164. An advantage of this design is that it allows the rate of water mist generation to be tuned to operate more continuously (and energy efficiently) while maintaining a set air humidity. For example, the controller172may reduce (but not halt) the flow power to the humidification unit164to slow (but not necessarily stop) the rate of water mist generation. Similarly, the controller172may send control signals to the humidification unit164instructing the humidification unit164to slow (but not necessarily halt) the rate of water mist generation. For example, if the humidity level approaches a set humidity level, then the rate of production of water mist may be reduced. The humidification unit164may include logic to receive and act upon signals received from one or more of a humidity sensor186, a water level sensor174and/or one or more temperature sensors182,184to vary the rate of water mist generation.

It will be appreciated that the controller172may regulate the amount of liquid water present in the humidification unit164. For example, the controller172may be communicatively coupled with the inlet and outlet valves196and198to regulate the supply and discharge of water to/from the humidification unit164based on, e.g., a signal provided by a water level sensor174. The controller172can direct the position of the inlet and outlet valves196and198to fill and drain the humidification unit164thereby controlling the amount of liquid water within the humidification unit164.

Temperature sensors182and184are operable to measure the temperature of the air adjacent to the sensors182and184. The temperature sensors182and184may be any suitable type of sensor for measuring temperature, such as a thermocouple, a thermistor, a mechanical sensor, etc. The temperature sensors182and184may include various shielding to reduce noise or other undesired signals.

As shown inFIG.2, the temperature sensors182and184can be positioned in the air flow path136of the fan coil100. In the illustrated example, the temperature sensor182is positioned downstream of the heat exchange unit160, and may be referred to herein as a downstream temperature sensor. Likewise, the temperature sensor184is positioned upstream of the heat exchange unit160, and may be referred to herein as an upstream temperature sensor. It will be appreciated that more than one upstream temperature sensor and/or more than one downstream temperature sensor may be provided.

The upstream temperature sensor182and the downstream temperature sensor184may be communicatively connected to the controller172(e.g., wired, wirelessly). In operation, upstream and downstream signals can be received by the controller172from the upstream and downstream temperature sensors182and184. The upstream and downstream signals may correspond to the temperature measured by the upstream and downstream temperature sensors182.

Accordingly the upstream and downstream signals may be used by the controller172to determine the operational mode of the fan coil100. In particular, the controller172may determine that the fan coil100is in a heating mode, a cooling mode, or inactive, based on the upstream and downstream signals. An advantage of this design is that the controller172can determine the operational mode of the fan coil100without obtaining signals from the control system of the fan coil100. Accordingly, a humidification unit164may be retrofitted into a fan coil100without having to connect controller172to the control system for the fan coil100.

For example, the controller172may compare the upstream and downstream signals to determine a temperature difference between the air upstream and downstream of the heat exchange unit160. If the downstream temperature exceeds the upstream temperature, the controller172may determine that the fan coil100is in a heating mode. If the upstream temperature exceeds the downstream temperature, the controller172may determine that the fan coil100is in a cooling mode. If the downstream temperature is approximately equal to the upstream temperature, the controller172may determine that the fan coil100is inactive. In some embodiments, various thresholds may be used when comparing the upstream and downstream signals. For example, the controller172may determine that the fan coil is in a heating mode if the downstream temperature exceeds the downstream temperature by a predetermined amount.

The controller172may activate the humidification unit164in response to determining the fan coil is in a heating mode. Similarly, the controller172may deactivate the humidification unit164when the fan coil100is not in a heating mode. An advantage of this design is that water mist is not generated unless the air flow is to be heated. Heating the air flow may reduce its relative humidity and thereby allow the air flow to better absorb the water mist. This can reduce accumulation of water (e.g., agglomerated water droplets in the water mist) inside the fan coil100.

The humidity sensor186is operable to measure the humidity of the air surrounding the sensor186. The humidity sensor186may be any suitable sensor for sensing humidity, such as a capacitive sensor, a resistive sensor, a gravimetric sensor, an optical sensor, etc. As shown inFIG.2, the humidity sensor186can be positioned in the air flow path136of the fan coil100. In the illustrated example, the humidity sensor186is positioned in the air flow path136downstream of the heat exchange unit160. It will be appreciated that more than one humidity sensor186may be provided and it may be provided at various locations. For example, it may be located to sense the humidity level in a room or at any location in fan coil100.

The humidity sensor186may be communicatively connected to the controller172(wired, wirelessly). In operation, the humidity sensor186can provide humidity signals to the controller172. The humidity signals can indicate the humidity of the air in the air flow path136measured by the humidity sensor186.

The controller172may activate or deactivate the humidification unit164in response to the humidity signals received from the humidity sensor186. For example, the controller172may deactivate the humidification unit164when the humidity level in the air flow path136is above a predetermined humidity level. Similarly, the controller172may activate the humidification unit164when the humidity level in the air flow path136is below a predetermined humidity level and, optionally, the fan coil100is in the heating mode. An advantage of this design is the humidification unit164is only activated as needed, which may reduce the overall power consumption of the humidification unit164.

The water level sensor174is operable to measure the amount of liquid water within the humidification unit164. In the illustrated example, the water level sensor174measures the water level (i.e., the elevation of the free surface of the liquid water) of the boiler206. The water level sensor174may be any suitable sensor for measuring the water level of a humidification unit164, such as the boiler206, such as an optical sensor, an electrical sensor, an ultrasonic sensor, a radar sensor, etc.

The water level sensor174may optionally determine the water level of the boiler206without directly sensing the water in the boiler206. For example, as shown inFIG.8, the water level sensor174may measure the water level of a tube176to determine the water level of the boiler206. In the illustrated example, the tube176is fluidly connected to the boiler206. The tube176is positioned so that the tube176has a water level that is substantially equal to the water level of the boiler206. An advantage of this design is that the water level sensor174can be located remote from the humidification unit164. The humidification unit164may at operate at high temperatures that may damage components located proximate to the humidification unit164.

In the example shown inFIG.8, the water level sensor174is an optical sensor. In the illustrated example, the optical water level sensor174measures the optical transmittance of the tube176at a particular elevation to detect the presence of water in the tube176at that elevation. The optical transmittance of the tube176at a particular elevation is relatively higher when the tube176contains water relative to when the tube176contains air at that elevation. In the illustrated example, the water level sensor174includes an optical transmitter and an optical receiver. The optical transmitter emits light towards the tube176. A first portion of the light is transmitted through the tube176(i.e., through the water or air stored therein) and a second portion of the light is reflected back towards the optical receiver. The optical receiver measures the quantity of reflected light to determine the optical transmittance and therefore the presence of water at a particular elevation of the tube176.

The water level sensor174may include any number or type of optical transmitters or receivers. In the illustrated example, the water level sensor174includes three pairs of infrared transmitters and receivers. Each pair of infrared transmitter and receiver is positioned to detect a particular water level of the tube176(and the boiler206). For example, a first transmitter and receiver pair may be used to detect an under filled water level, a second transmitter and receiver pair may be used to detect a desired water level, and a third transmitter and receiver pair may detect an over filled water level.

The water level sensor174can provide water level signals to the controller172. The water level signals may provide an indication of the water level of the boiler206measured by the water level sensor174. The water level signals may trigger the controller172to control various aspects of the humidification unit164.

For example, the controller172may deactivate the boiler206in response to a water level signal provided when the boiler206is above a predetermined water level, or when the boiler206is below a predetermined water level. An advantage of this design is that humidification unit164can deactivate the boiler206when there is excessive or insufficient water, to avoid damaging the humidification unit164.

Operating the humidification unit164with excessive water may cause water to enter the water vapor outlet204. Operating the humidification unit164with insufficient water may cause the humidification unit164to overheat.

Optionally, the controller172may regulate the water level of the boiler206, based on a water level signal provided by the water level sensor174. For example, the controller172may be operably connected to the inlet and outlet valves196and198. The controller172may be provided with a water level signal from the water level sensor174when the water level in the boiler206is above or below a predetermined water level. In response, the controller172may actuate the inlet valve196or the outlet valve198to admit water to the boiler206or drain the boiler206. An advantage of this design is that the humidification unit164can be operated to maintain a desired water level within the boiler206, and avoid under filling or overfilling the boiler206.

In the illustrated example, the water level sensor174is shown mounted on the controller172. However, it should be appreciated that in alternate embodiments, the water level sensor174may located remote from the controller172.

Flushing the Boiler

In accordance with this aspect, the water vapor (mist) producing element of a humidification unit is flushed to reduce or prevent the buildup of minerals and/or microbial growth in the water vapor (mist) producing element. The following is a general description of a method that may be implemented using a boiler of a humidification unit. The following description contains various features which may be used individually or in any combination or sub-combination. For ease of exposition, the method is described below with reference to the example boiler206and the example humidification unit164described above. However, it should be appreciated that the method may be implemented with any boiler of any humidification unit.

Referring toFIG.9, there is shown an example method300for operating the boiler206of the humidification unit164. The method300may be used to flush the boiler206by repeatedly draining and filling the boiler206. Microbes and/or minerals within the boiler206may be removed along with the water as the water is drained from the boiler206.

An advantage of the flushing method300is that the accumulation of minerals within the boiler206may be reduced. Minerals dissolved in water may be deposited in the boiler206over time, as liquid water is converted into water vapor. The buildup of residual minerals within the boiler206may reduce the efficiency of the humidification unit164, reducing heat transfer efficiency or increasing water boiling turbidity. In addition, the flushing method300may reduce microbial growth within the boiler206. Microbes, such as bacteria or fungi, may grow within the boiler206when water is stored for long periods of time. The microbes may present health risks when discharged from the boiler206.

Prior to the commencement of the flushing method300, the boiler206is initially filled to a first water level. The first water level is typically the water level of the boiler206during normal operation. The flushing method300begins at302, when the boiler206is drained to substantially remove water from the boiler206. For example, the controller172may actuate the outlet valve198to discharge water from the boiler206.

The boiler206may be deactivated prior to step302. For example, the controller172may stop the boiling of water within the boiler206prior to draining the boiler206at302.

At304, the boiler206is subsequently filed with water to a second water level. For example, the controller172may actuate the inlet valve196to admit water into the boiler206. The controller172may control the inlet valve196based on water level signals received from the water level sensor174indicating when the boiler206is at the second water level. The second water level is greater than the first water level (i.e., which the boiler206is initially filled prior to the commencement of the flushing method300). Overfilling the boiler206beyond the normal water level of the boiler206may allow additional minerals and/or microbes to be removed when the boiler206is subsequently drained.

At306, the boiler206is subsequently drained again to substantially remove water from the boiler206. Similar to at302, the controller172may actuate outlet valve198to discharge water from the boiler206again.

At308, the boiler206is subsequently filled with water, optionally to a level above the first water level such as to the second water level. Similar to at304, the controller172may actuate the inlet valve196to admit water into the boiler206based on water level signals received from the water level sensor174. Overfilling the boiler206a second time may remove additional minerals and/or microbes which may not have been removed by the first overfill and drain (i.e., at304and306) once the boiler206is subsequently drained.

At310, the boiler206is subsequently drained to substantially remove water from the boiler206again. Similar to at302and306, the controller172may actuate the outlet valve198to discharge water from the boiler206.

Optionally, at312, the boiler206is subsequently filled with water to the first water level. For example, the controller172may actuate the inlet valve196to admit water into the boiler206based on water level signals received from the water level sensor174. By filling the boiler206back to the first water level, the boiler206may be ready for normal operation. For example, subsequent to step312, the controller172may activate boiler206to boil the water in the boiler206. In other embodiments, step312may be omitted. That is, the flushing method300may conclude at310. For example, the boiler206may not be filled in anticipation that the boiler206will remain inactive for a relatively long period of time. Storing substantially no water in the boiler may prevent microbial growth in the boiler206while the boiler206is inactive. In such embodiment, controller172may first send signal to fill the boiler206when the fan coil is in a heating mode prior to energizing boiler206.

In some embodiments, the flushing method300may be initiated in response to the detection of a trigger condition. That is, prior to draining the boiler206(i.e., at302,306, and310) and filling the boiler206(i.e., at304and308), a condition triggering the commencement of the flushing method300is detected. In other words, the boiler is only drained (i.e., at302,306, and310) and filled (i.e., at304,308, and312) if the trigger condition is detected. Various trigger conditions may cause the commencement of the flushing method300.

In some embodiments, the trigger condition may be the boiler206being inactive for a predetermined time period. For example, the inactive predetermined time period may be between 18 and 48 hours, 18 and 36 hours, 24 hours, 48 to 96 hours, 54 to 90 hours, or 72 hours. Flushing the boiler206when the boiler206is inactive may reduce microbial growth within the idle water of the boiler206.

In some embodiments, the trigger condition may be the boiler206being active for a predetermined time period. For example, the active predetermined time period may be over 15 minutes, over 30 minutes, or 60 minutes. Flushing the boiler206when the boiler206is active may reduce the buildup of minerals deposited by evaporating water.

In some embodiments, the trigger condition may be the boiler206containing water exceeding a predetermined salinity level. For example, the boiler206may include one or more sensors for measuring the salinity level of the water in communication with the controller172. In some embodiments, the trigger condition may be the boiler206exceeding a predetermined water level when the humidification unit is active. The turbidity of the water within the boiler206during boiling may increase when the water has a high salinity level.

In some embodiments, there may be more than one trigger condition, and the flushing method300may be initiated in response to the trigger condition that occurs first. For example, the trigger conditions may include the boiler206being inactive for an inactive predetermined time period and the boiler206being active for an active predetermined time period. The commencement of the flushing method300may be triggered by whichever trigger condition occurs first.

In some embodiments, the flushing method300may be initiated more than once in response to the detection of more than one trigger condition. For example, the flushing method300may be initiated in response to the detection of a first trigger condition. Subsequent to the executing the flushing method300, a second trigger condition may be detected, triggering a second instance of the flushing method300. For example, the first trigger condition may be the boiler206being inactive for a first inactive predetermined time period and the second trigger condition may be the boiler206being inactive for a second inactive predetermined time period that is greater than the first inactive predetermined time period. For instance, the first inactive predetermined time period may be between 18 and 48 hours, between 18 and 36 hours, or 24 hours, and the second predetermined time period may be between 48 and 96 hours, 54 and 90 hours, or 72 hours.

Referring now toFIG.10, there is shown another example method400of operating the boiler206of the humidification unit164, in accordance with an embodiment. The method400may be used to flush the boiler206in accordance with the flushing method300in response to various trigger conditions.

The method400begins at402, where the operational state of the boiler206is determined. If the boiler206is inactive, the method400proceeds to404. Alternatively, if the boiler206is active, the method400proceeds to414.

At404, the amount of time that the boiler206has been inactive is determined. If the inactivity time of the boiler is greater than or equal to a first inactive predetermined time period (i.e., TI1), the method400proceeds to406. Otherwise, the method400proceeds back to402. For example, the first inactive predetermined time period may be between 18 and 48 hours, between 18 and 36 hours, or 24 hours.

At406, the boiler206is flushed in accordance with the flushing method300. The boiler206is filled in accordance with optional step312of the flushing method300.

At408, if the inactivity time of the boiler206is greater than or equal to a second inactive predetermined time period (i.e., TI2), the method400proceeds to410. Otherwise, the method proceeds back to402. For example, the second predetermined time period may be between 48 and 96 hours, 54 and 90 hours, or 72 hours.

At410, the boiler206is flushed in accordance with the flushing method300again. However, in contrast to step406, the boiler206is not filled, by skipping step312of the flushing method300. Accordingly, following the execution of step410, the boiler206is substantially empty.

At412, similar to at402, the operational state of the boiler206is determined. If the boiler206is not active, the method400proceeds to back to412. Alternatively, if the boiler206is active, the method proceeds back to402.

At414, the length of time that the boiler206has been active is determined. If the activity time of the boiler is greater an active predetermined time period (i.e., TA), the method400proceeds to416. Otherwise, the method proceeds back to402. For example, the active predetermined time period may be over 15 minutes, over 30 minutes, or 60 minutes.

At416, similar to at406, the boiler206is flushed in accordance with the flushing method300. The boiler is refilled in accordance with optional step312. The method then proceeds back to402.

It will be appreciated that different flushing patterns may be used based upon different triggering signals. Therefore, if the triggering event is the first inactive predetermined time period, only a single flushing operation304may be conducted. However, after a longer inactive predetermined time period, two flushing operations (operations304and308) may be conducted.

Similarly, after a first shorter total period of operation (e.g., 15-30 minutes) only a single flushing operation304may be conducted. However, after a longer total period of operation (e.g., over 45 minutes, over 60 minutes, etc.), two flushing operations (operations304and308) may be conducted

While the above description describes features of example embodiments, it will be appreciated that some features and/or functions of the described embodiments are susceptible to modification without departing from the spirit and principles of operation of the described embodiments. For example, the various characteristics which are described by means of the represented embodiments or examples may be selectively combined with each other. Accordingly, what has been described above is intended to be illustrative of the claimed concept and non-limiting. It will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto. The scope of the claims should not be limited by the preferred embodiments and examples, but should be given the broadest interpretation consistent with the description as a whole.