Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
  • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
  • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
  • F24F3/1405—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification in which the humidity of the air is exclusively affected by contact with the evaporator of a closed-circuit cooling system or heat pump circuit
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F11/00—Control or safety arrangements
  • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
  • F24F11/63—Electronic processing
  • F24F11/64—Electronic processing using pre-stored data
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F11/00—Control or safety arrangements
  • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F11/00—Control or safety arrangements
  • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
  • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
  • F24F11/86—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling compressors within refrigeration or heat pump circuits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
  • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
  • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
  • F24F3/153—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification with subsequent heating, i.e. with the air, given the required humidity in the central station, passing a heating element to achieve the required temperature
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D22/00—Control of humidity
  • G05D22/02—Control of humidity characterised by the use of electric means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F11/00—Control or safety arrangements
  • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
  • F24F11/41—Defrosting; Preventing freezing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
  • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
  • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
  • F24F2003/144—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification by dehumidification only
  • F24F2003/1446—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification by dehumidification only by condensing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F2110/00—Control inputs relating to air properties
  • F24F2110/10—Temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F2110/00—Control inputs relating to air properties
  • F24F2110/20—Humidity

Definitions

• This invention relates to dehumidifiers of the kind which include a vapour compression circuit in which a compressor circulates refrigerant vapour through a condenser, an expansion device and an evaporator for removing water vapour from air passing through the dehumidifier.
• dehumidifiers are controlled by a humidistat which senses the relative humidity (RH) of the air, causing the dehumidifier to run when the RH exceeds a set level which is adjustable by the user.
• RH relative humidity
• the structure and fittings of a house or other building tend to absorb water vapour so that when a dehumidifier is operated in the building for the first time it needs to run continuously for several weeks until the excess moisture is removed. Once the building and its contents have dried out however, the dehumidifier only needs to remove peaks of moisture which may be caused by cooking, running a shower, drying clothes etc. Apart from peaks of moisture, water vapour is also continuously added to the air within a building at a slower rate from various sources such as through breathing out water vapour. This too can cause excess moisture to build up over a period, which is absorbed into the structure and fittings ofthe building and also critically increases the RH in cooler areas. This too must be removed on a daily basis regardless of the prevailing RH level.
• the RH in a building also varies with the seasons. During summer months the RH is often relatively high, but in winter the RH tends to be lower due to lower external humidity and heating within the building. On the other hand, the RH will be higher in unheated rooms or adjacent to a window because the air temperature will be lower. Thus, measuring the RH with a centrally- placed humidistat may give an RH reading of only 50% whereas colder areas ofthe same room could be as high as 80% or even 100% on windows and other cold surfaces giving rise to condensation.
• the present invention seeks to provide a new and inventive form of dehumidifier which is more efficient than existing dehumidifiers.
• the present invention proposes a dehumidifier of the kind which includes housing having an air inlet and an air outlet and containing a vapour compression circuit in which a compressor circulates refrigerant vapour through a condenser, an expansion device and an evaporator for removing water vapour from air passing through the housing, characterised in that the dehumidifier is arranged to monitor changes in a relevant environmental parameter over a period of time to establish a reference level for the said parameter, and the operation of the dehumidifier is determined by whether the current value of the parameter is above or below the reference level.
• the relevant environmental parameter may be any parameter which affects the likelihood of condensation. In most cases the parameter will be RH, although environmental temperature may also be used.
• the dehumidifier runs when the current RH is above the reference level.
• the duty cycle during low RH periods can be set by the user, so that the dehumidifier may run for, say 75% or 50% of the time.
• an override condition may be selected during which the dehumidifier runs continuously irrespective of the prevailing RH level.
• the dehumidifier When the current RH level rises above a predetermined maximum the dehumidifier preferably runs continuously. Conversely, when the RH level falls below a predetermined minimum level the dehumidifier may be permanently off.
• the invention also provides a dehumidifier which is characterised in that A tie dehumidifier is arranged to monitor changes in a relevant environmental parameter over a period of time to establish a reference level for the said parameter, and the operation of the dehumidifier is determined by whether the current value of the parameter is above or below the reference level, in which a number of individual readings of said environmental parameter are stored at intervals over said period and the reference level is set at a value where half of the stored readings fall above the reference level and half fall below.
• Such an arrangement avoids the risk of large deviations from the average for a relatively short period causing a disproportionate effect on the reference level, e.g. due to cooking or running a shower.
• FIG. 1 is a schematic diagram of a dehumidifier in accordance with the invention.
• Figure 2 is a graph showing how the "on" and “off' times of the dehumidifier may vary with relative humidity RH.
• the dehumidifier shown in Fig. 1 includes a housing 10 having an air inlet 8 and an air outlet 9.
• the housing contains a vapour compression circuit 1 in which a compressor 2 circulates refrigerant vapour under pressure through a condenser 3 wherein the refrigerant condenses and gives out heat.
• Condensed refrigerant then passes through an expansion device 4 such as a valve or small bore tube providing a restriction which reduces the temperature and pressure of the refrigerant entering evaporator coils 5.
• Vaporisation of the refrigerant in the evaporator 5 absorbs heat from ambient air so that the resulting temperature drop causes water vapour in the air to condense out on the surfaces ofthe evaporator coils.
• the ambient air is drawn into the dehumidifier by a fan 6, and after passing over the evaporator coils the air passes over the condenser to receive heat from the refrigerant so that the dehumidifier discharges warm air into the external environment.
• Refrigerant vapour from the evaporator coils is recirculated by the compressor 2 in a continuous cycle of condensation and evaporation.
• the operation ofthe dehumidifier is overseen by an electronic controller 11 , which also receives input from a RH sensor 12 arranged to monitor the ambient air at the point where it enters the dehumidifier before contact with the evaporator 5.
• the controller 11 also receives input from a temperature sensor 13, which is also arranged to monitor the ambient air entering the dehumidifier. It would also be possible for one or both of the sensors to be mounted elsewhere, inside or outside the dehumidifier, with an offset being applied to the readings to compensate if necessary.
• the controller 11 may control the compressor 2 and the fan 6 such that the compression circuit operates with alternating run and defrost cycles in known manner.
• the controller will typically include a microprocessor which reads data from the humidity sensor 12.
• the controller may take periodic readings from the RH sensor 12 and temperature sensor 13 (e.g. every 30 minutes) which are stored in RAM. At the end of this period the stored RH readings may be used to compute a reference RH level which, in a simple example, may be the average of the stored readings.
• the reference level RH r ⁇ f will depend on the average RH level over the monitored period, but once the reference value has been established it is used to provide a fixed reference level for control ofthe dehumidifier over a succeeding period.
• the RH level may be monitored during successive discrete periods which are used to control the dehumidifier over the succeeding monitoring period it is generally preferable to continuously update the calculated reference values, or at least update the reference values at much shorter periods. Thus, every hour the values can be recalculated to include the most recent readings, at the same time omitting the oldest readings.
• the current RH will vary throughout any given period, and when the prevailing RH rises above the reference level, for example due to cooking etc. as indicated by the sub-periods C, and C 2 , the dehumidifier is operated to run continuously.
• the "on" periods of the dehumidifier are indicated by the solid black lines whereas the "off' periods are indicated by thin lines. This will ensure that any transient increases in humidity will be removed with optimum effect.
• the dehumidifier runs at a reduced duty cycle which is illustrated in Fig. 2 by alternating relatively short "on” and “off' periods.
• a 50% duty cycle is illustrated by way of example, but the actual duty cycle may vary and could, for example, be user-selectable at say 75% and 50% figures.
• the dehumidifier will operate intermittently to remove water from the atmosphere.
• the dehumidifier When the RH value is below the reference level it might be preferable to operate the dehumidifier more at some times of the day than others (e.g. at night). This could be achieved by providing the controller 11 with a real-time clock.
• a 75% duty cycle setting could be achieved by running the dehumidifier continuously for 12 hours at night and then running at 50% duty cycle during the day so that, overall, the average duty cycle is about 75% over a 24 hour period.
• the 50% setting could be achieved by a continuous run period and a 25% duty cycle period, or by 75% and 25% duty cycle periods, etc.
• a "continuous" mode may be selected during which the dehumidifier runs continuously irrespective of the actual RH level. This mode may, for example, be useful for drying out new or excessively damp buildings.
• Fig. 2 also shows predetermined maximum and minimum humidity levels, RH max and RH min , which may be pre-programmed into the controller or calculated by the controller 11. Should the current RH reading exceed the maximum value the dehumidifier will operate continuously during the period in question regardless of RH ref . This again ensures that a particularly damp building will be subjected to maximum drying. Similarly, should the current RH fall below the minimum RH level the dehumidifier will be continuously "off', thus preventing the dehumidifierfrom operating in very dry buildings for example. Again, user-selected override settings are possible.
• the controller would be storing periodic RH readings from which a new RH ref value can be calculated for use as the reference RH level during the following period.
• the reference level is always determined by the average RH level during the preceding period.
• the dehumidifier In some circumstances it might be preferable to control the dehumidifier against the average temperature readings taken from the sensor 13 rather than the average RH readings. This would allow the dehumidifier to run more during the night for example (lower average temperature) to enable morning condensation to be reduced, or to run more during the day (higher average temperature) when water extraction is higher.
• the mode of operation can be selectable by the user.
• a dehumidifier of the kind which includes housing having an air inlet and an air outlet and containing a vapour compression circuit in which a compressor circulates refrigerant vapour through a condenser, an expansion device and an evaporator for removing water vapour from air passing through the housing, characterised in that the dehumidifier is arranged to monitor changes in a relevant environmental parameter over a period of time to establish a reference level for the said parameter, and the operation of the dehumidifier is determined by whether the current value of the parameter is above or below the reference level.
• a dehumidifier according to Claim 1 in which the said environmental parameter is relative humidity (RH).
• a dehumidifier according to Claim 2 in which the dehumidifier runs for a longer period when the current RH is above the established reference level than it does when the RH is below the reference level.
• a dehumidifier according to Claim 3 in which the dehumidifier runs continuously when the current RH is above the established reference level.
• a dehumidifier according to Claim 2, 3 or 4 in which the duty cycle (on/off ratio) of the dehumidifier when the RH is below the reference level is user-controllable.
• a dehumidifier according to Claim 1 in which the said environmental parameter is temperature.
• a dehumidifier according to any preceding claim in which the reference level is obtained from a number of individual readings which are stored at intervals over a preceding period.
• a dehumidifier according to Claim 10 in which the reference level is determined by an average value of the stored readings.
• a dehumidifier according to Claim 10 in which the reference level is where half of the stored readings fall above and half fall below.
• a dehumidifier characterised in that the dehumidifier is arranged to monitor changes in a relevant environmental parameter over a period of time to establish a reference level for the said parameter, and the operation of the dehumidifier is determined by whether the current value of the parameter is above or below the reference level, in which a number of individual readings of said environmental parameter are stored at intervals over said period and the reference level is set at a value where half of the stored readings fall above the reference level and half fall below.
• IPC International Patent Classification
• This invention relates to dehumidifiers of the kind which include a vapour compression circuit in which a compressor circulates refrigerant vapour through a condenser, an expansion device and an evaporator for removing water vapour from air passing through the dehumidifier.
• dehumidifiers are controlled by a humidistat which senses the relative humidity (RH) of the air, causing the dehumidifier to run when the RH exceeds a set level which is adjustable by the user.
• RH relative humidity
• the structure and fittings of a house or other building tend to absorb water vapour so that when a dehumidifier is operated in the building for the first time it needs to run continuously for several weeks until the excess moisture is removed. Once the building and its contents have dried out however, the dehumidifier only needs to remove peaks of moisture which may be caused by cooking, running a shower, drying clothes etc. Apart from peaks of moisture, water vapour is also continuously added to the air within a building at a slower rate from various sources such as through breathing out water vapour. This too can cause excess moisture to build up over a period, which is absorbed into the structure and fittings ofthe building and also critically increases the RH in cooler areas. This too must be removed on a daily basis regardless of the prevailing RH level.
• the RH in a building also varies with the seasons. During summer months the RH is often relatively high, but in winter the RH tends to be lower due to lower external humidity and heating within the building. On the other hand, the RH will be higher in unheated rooms or adjacent to a window because the air temperature will be lower. Thus, measuring the RH with a centrally- placed humidistat may give an RH reading of only 50% whereas colder areas ofthe same room could be as high as 80% or even 100% on windows and other cold surfaces giving rise to condensation.
• the present invention seeks to provide a new and inventive form of dehumidifier which is more efficient than existing dehumidifiers.
• the present invention proposes a dehumidifier of the kind which includes housing having an air inlet and an air outlet and containing a vapour compression circuit in which a compressor circulates refrigerant vapour through a condenser, an expansion device and an evaporator for removing water vapour from air passing through the housing, characterised in that the dehumidifier is arranged to monitor changes in a relevant environmental parameter over a period of time to establish a reference level for the said parameter, and the operation of the dehumidifier is determined by whether the current value of the parameter is above or below the reference level.
• the relevant environmental parameter may be any parameter which affects the likelihood of condensation. In most cases the parameter will be RH, although environmental temperature may also be used.
• the dehumidifier runs when the current RH is above the reference level.
• the duty cycle during low RH periods can be set by the user, so that the dehumidifier may run for, say 75% or 50% of the time.
• an override condition may be selected during which the dehumidifier runs continuously irrespective ofthe prevailing RH level.
• the dehumidifier When the current RH level rises above a predetermined maximum the dehumidifier preferably runs continuously. Conversely, when the RH level falls below a predetermined minimum level the dehumidifier may be permanently off.
• the invention also provides a dehumidifier which is characterised in thatthe dehumidifier is arranged to monitor changes in a relevant environmental parameter over a period of time to establish a reference level for the said parameter, and the operation of the dehumidifier is determined by whether the current value of the parameter is above or below the reference level, in which a number of individual readings of said environmental parameter are stored at intervals over said period and the reference level is set at a value where half of the stored readings fall above the reference level and half fall below.
• Such an arrangement avoids the risk of large deviations from the average for a relatively short period causing a disproportionate effect on the reference level, e.g. due to cooking or running a shower.
• FIG. 1 is a schematic diagram of a dehumidifier in accordance with the invention.
• Figure 2 is a graph showing how the "on” and “off times ofthe dehumidifier may vary with relative humidity RH.
• the dehumidifier shown in Fig. 1 includes a housing 10 having an air inlet 8 and an air outlet 9.
• the housing contains a vapour compression circuit 1 in which a compressor 2 circulates refrigerant vapour under pressure through a condenser 3 wherein the refrigerant condenses and gives out heat.
• Condensed refrigerant then passes through an expansion device 4 such as a valve or small bore tube providing a restriction which reduces the temperature and pressure of the refrigerant entering evaporator coils 5.
• Vaporisation of the refrigerant in the evaporator 5 absorbs heat from ambient air so that the resulting temperature drop causes water vapour in the air to condense out on the surfaces ofthe evaporator coils.
• the ambient air is drawn into the dehumidifier by a fan 6, and after passing over the evaporator coils the air passes over the condenser to receive heat from the refrigerant so that the dehumidifier discharges warm air into the external environment.
• Refrigerant vapour from the evaporator coils is recirculated by the compressor 2 in a continuous cycle of condensation and evaporation.
• the operation ofthe dehumidifier is overseen by an electronic controller 11 , which also receives input from a RH sensor 12 arranged to monitor the ambient air at the point where it enters the dehumidifier before contact with the evaporator 5.
• the controller 11 also receives input from a temperature sensor 13, which is also arranged to monitor the ambient air entering the dehumidifier. It would also be possible for one or both of the sensors to be mounted elsewhere, inside or outside the dehumidifier, with an offset being applied to the readings to compensate if necessary.
• the controller 11 may control the compressor 2 and the fan 6 such that the compression circuit operates with alternating run and defrost cycles in known manner.
• the controller will typically include a microprocessor which reads data from the humidity sensor 12. 6
• the controller may take periodic readings from the RH sensor 12 and temperature sensor 13 (e.g. every 30 minutes) which are stored in RAM. At the end of this period the stored RH readings may be used to compute a reference RH level which, in a simple example, may be the average of the stored readings.
• the reference level RH ref will depend on the average RH level over the monitored period, but once the reference value has been established it is used to provide a fixed reference level for control ofthe dehumidifier over a succeeding period.
• the RH level may be monitored during successive discrete periods which are used to control the dehumidifier over the succeeding monitoring period it is generally preferable to continuously update the calculated reference values, or at least update the reference values at much shorter periods. Thus, every hour the values can be recalculated to include the most recent readings, at the same time omitting the oldest readings.
• the current RH will vary throughout any given period, and when the prevailing RH rises above the reference level, for example due to cooking etc. as indicated by the sub-periods C, and C 2 , the dehumidifier is operated to run continuously.
• the "on" periods ofthe dehumidifier are indicated by the solid black lines whereas the "off' periods are indicated by thin lines. This will ensure that any transient increases in humidity will be removed with optimum effect.
• the dehumidifier runs at a reduced duty cycle which is illustrated in Fig. 2 by alternating relatively short "on” and “off periods.
• a 50% duty cycle is illustrated by way of example, but the actual duty cycle may vary and could, for example, be user-selectable at say 75% and 50% figures.
• the dehumidifier will operate intermittently to remove water from the atmosphere.
• the dehumidifier When the RH value is below the reference level it might be preferable to operate the dehumidifier more at some times ofthe day than others (e.g. at night). This could be achieved by providing the controller 11 with a real-time clock.
• a 75% duty cycle setting could be achieved by running the dehumidifier continuously for 12 hours at night and then running at 50% duty cycle during the day so that, overall, the average duty cycle is about 75% over a 24 hour period.
• the 50% setting could be achieved by a continuous run period and a 25% duty cycle period, or by 75% and 25% duty cycle periods, etc.
• a "continuous" mode may be selected during which the dehumidifier runs continuously irrespective of the actual RH level. This mode may, for example, be useful for drying out new or excessively damp buildings.
• Fig. 2 also shows predetermined maximum and minimum humidity levels, RH max and RH min , which may be pre-programmed into the controller or calculated by the controller 11. Should the current RH reading exceed the maximum value the dehumidifier will operate continuously during the period in question regardless of RH ref . This again ensures that a particularly damp building will be subjected to maximum drying. Similarly, should the current RH fall below the minimum RH level the dehumidifier will be continuously "off, thus preventing the dehumidifier from operating in very dry buildings for example. Again, user-selected override settings are possible.
• the controller would be storing periodic RH readings from which a new RH ref value can be calculated for use as the reference RH level during the following period.
• the reference level is always determined by the average RH level during the preceding period.
• the dehumidifier In some circumstances it might be preferable to control the dehumidifier against the average temperature readings taken from the sensor 13 rather than the average RH readings. This would allow the dehumidifier to run more during the night for example (lower average temperature) to enable morning condensation to be reduced, or to run more during the day (higher average temperature) when water extraction is higher.
• the mode of operation can be selectable by the user.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
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• Fuzzy Systems (AREA)
• Mathematical Physics (AREA)
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• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Drying Of Gases (AREA)
• Air Conditioning Control Device (AREA)

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Citations (4)

• 2004
  • 2004-04-01 EP EP04725091.5A patent/EP1620771B1/en not_active Expired - Lifetime
  • 2004-04-01 WO PCT/GB2004/001402 patent/WO2004090653A1/en not_active Ceased

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