Control method and device for an air conditioning economizer system

In an air conditioning economizer system outdoor air intake is reduced automatically by a control device based on a shut-off control setting for a measured outdoor air quality. A geographical location associated with the air conditioning economizer system is received (S2) in the control device. The control device defines automatically (S3) the shut-off control setting based on the geographical location. Thus, the air conditioning economizer system is adapted specifically for a geographic location and its climate zone, without the requirement for installing or operating personnel to determine a shut-off control setting for a specific climate zone and/or select a corresponding operating range.

FIELD OF THE INVENTION

The present invention relates to a control method and a control device for an air conditioning economizer system. Specifically, the present invention relates to a control method and a control device for reducing automatically in an air conditioning economizer system outdoor air intake based on a shut-off control setting for a measured outdoor air quality.

BACKGROUND OF THE INVENTION

In the building construction industry there exist many standards that are adopted into codes and by extension become local law. These codes govern mechanical and electrical systems, fire protection and life safety, structural, space, and envelop requirements, and energy conservation (Energy Code).

The Energy Code dictates requirements of a building envelop, Heating Ventilation and Air Conditioning (HVAC) systems, water heating, electrical power, and electrical lighting. Within this code are several references to the climate zone the building is being built in. Typically, the climate zones have been defined based on historical meteorological data collection of temperatures, humidity, snow fall, rain fall and other such weather occurrences. The Energy Code uses the climate zone to determine the materials and systems that are required to result in the best investment versus operating cost. Some building systems that are static such as the insulation and vapor barriers can be chosen and installed in the building to protect against extreme cold, heat, and humidity. Other systems such as air conditioning economizer systems are dynamic and have to be adjusted in the field rather than set in the factory in order to achieve the requirements of the Energy Code. The controls of these dynamic systems have to be parameterized such that they function to achieve highest operating energy efficiencies. If the controls are improperly set, they can reduce energy savings or in many cases increase energy use.

Within the Energy Code there are detailed requirements of the set points of operation of specific systems. In the case of air conditioning economizer systems, systems that use outdoor (outside) air to cool the building when conditions are suitable, the parameters of the control determine when air should be brought into a building and when it should not. For example, the specific climate zone setting as defined by the ASHRAE 90.1-2007 for the economizer system is shown in Table 1 below.

To use Table 1, the installer has to know what sensor control type is being used in the system. This is listed in the 1stcolumn. Listed in the 2ndcolumn are the approved climate zones where these sensor control types can be used. The location of the climate zones are shown on a map, as illustrated inFIG. 1for the USA, for example. The 3rdcolumn indicates the allowed equations for the sensor types used. These equations set the high limit shut-off. This shut-off requires selection or parameterizing in the field.

The map inFIG. 1(climate map and climate zones based in part on Köppen climate classification) shows not only the hot, moderate, and cold climate zones, but also indicates whether the zone is dry (B), moist (A), or very moist, i.e. marine (C). The setting of this system does not only determine when (seasonally) one should not bring hot air into a space to be cooled, but also when not to bring air that may be very moist. The moist air (humidity) will not only cause discomfort, but can result in conditions within the building that are suitable for mold growth, or provide other unhealthy air quality situations.

In a required climate zone setting according to the ASHRAE 90.1-2007 Energy Standard, all air economizers shall be capable of automatically reducing outdoor air intake to the design minimum outdoor air quantity when outdoor air intake will no longer reduce cooling energy usage. High-limit shut-off control settings shall be those listed in Table 1.

State of the art control devices require detailed review of the example table above by the installing or operating personnel to determine the correct set point, in order to meet the local law for the climate zone where the air conditioning economizer system is installed. Then the individual must select a corresponding operating range, e.g. through use of selector switch(es). If the individual does not have in his possession the tables and listing of climate zones, then the system can be incorrectly set up and result in energy waste and bad building conditions in moist climates. Multiple studies have proven this possibility to be true.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a control method and a control device for reducing automatically in an air conditioning economizer system outdoor air intake based on a shut-off control setting (value) for a measured outdoor air quality, which control method and a control device do not have at least some of the disadvantages of the prior art. In particular, it is an object of the present invention to provide a control method and a control device for reducing automatically in an air conditioning economizer system outdoor air intake based on a shut-off control setting (value) for a measured outdoor air quality, which control method and control device do not require installing or operating personnel to determine a shut-off control setting (value) for a specific climate zone and/or select a corresponding operating range.

According to the present invention, these objects are achieved particularly through the features of the independent claims. In addition, further advantageous embodiments follow from the dependent claims and the description.

According to the present invention, the above-mentioned objects are particularly achieved in that a control device for reducing automatically in an air conditioning economizer system outdoor air intake, based on a shut-off control setting for a measured outdoor air quality, comprises a location determination module configured to determine a geographical location, and a configuration module configured to define automatically the shut-off control setting based on the geographical location. Specifically, the shut-off control setting is defined automatically based on the climate zone associated with the geographical location, Thus, the air conditioning economizer system is adapted specifically for a geographic location and its climate zone, without the requirement for installing or operating personnel to determine a shut-off control setting for a specific climate zone and/or select a corresponding operating range.

In an embodiment, the device further comprises a table for mapping geographical locations to shut-off control settings. Thus, for a given geographical location, the device determines the shut-off control directly from a table stored in the control device. In an alternative embodiment, the device includes a table for mapping geographical locations to climate zones, and the configuration module is configured to define the shut-off control setting based on the climate zone assigned to the geographical location. Thus, for a given geographical location, the device determines a climate zone from a climate zone table stored in the control device, and, subsequently, the device determines the shut-off control setting assigned to this climate zone.

In an embodiment, the location determination module includes a user interface for entering geographical location data defining the geographical location, and the geographical location data includes a postal code, an area code, a state and county name, and/or geographical coordinates. Thus, the device receives the geographical location data through a user interface. For example, the user interface includes a touch screen for displaying a geographical map and entering the geographical location data through touching a geographical location depicted on the geographical map.

In another embodiment, the location determination module includes a receiver for a satellite-based positioning system, e.g. a GPS receiver (Global Positioning System). Alternatively, the location determination module includes an interface for receiving geographical location data from an external receiver for a satellite-based positioning system. Thus, the geographical location is determined by way of an internal or external positioning receiver.

In yet a further embodiment, the configuration module is configured to define the shut-off control setting based on a sensor type which defines the type of sensor used for measuring the outdoor air quality. Thus, the device defines the shut-off control setting based on a sensor type configured for the control device.

In addition to the control device, the present invention also relates to a control method for reducing automatically in an air conditioning economizer system outdoor air intake based on a shut-off control setting for a measured outdoor air quality. The method comprises storing (at least temporarily) in a control device of the air conditioning economizer system a geographical location, and defining automatically in the control device the shut-off control setting based on the geographical location.

The present invention further relates to a control device for setting in an air conditioning economizer system a shut-off control value for limiting outdoor air intake based on a measured outdoor air quality, the device comprising a location determination module configured to receive geographical location data defining a geographical location, and a configuration module configured to define automatically the shut-off control value based on the geographical location data.

The present invention also relates to a control method for setting in an air conditioning economizer system a shut-off control value for limiting outdoor air intake based on a measured outdoor air quality. The method comprises receiving in a control device of the air conditioning economizer system geographical location data defining a geographical location, and defining automatically in the control device the shut-off control value based on the geographical location data.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

InFIG. 3, reference numeral30refers to a control device for an air conditioning economizer system31. Depending on the embodiment, the control device30and the economizer system31are integrated in one common economizer housing38, or the control device30is integrated in a separate controller housing connected through control wires to the economizer system31.

The control device30is configured to reduce automatically in the economizer system31the outdoor air intake based on the value of a shut-off control setting for a measured outdoor air quality. For example, the air conditioning economizer system31includes sensors for measuring the temperature, humidity, dew point, and/or enthalpy of the outdoor air. In an embodiment, the economizer system31may also include sensors for measuring the air temperature and/or enthalpy of return air to the economizer system31. One skilled in the art will understand that the air conditioning economizer system31may include other sensors and modules for determining various other types of air quality considered useful for controlling automatically based thereon the outdoor air intake in the economizer system31.

As illustrated schematically inFIG. 3, in an embodiment, control device30includes a data store for storing the type of sensor(s)36used by the economizer system31. For example, the type of sensor(s)36is stored in the control device30at manufacturing time (factory settings) or at installation time, e.g. entered manually or detected automatically from the economizer system31or the sensors.

InFIG. 3, reference numeral32refers to a location determination module for determining a geographical location. In various embodiments, the location determination module32includes preferably a user interface50for entering and receiving geographical location data defining the geographical location. Alternatively, the location determination module32includes a receiver for a satellite-based positioning system, or an interface for receiving geographical location data from an external receiver for a satellite-based positioning system. Preferably, the control device1includes a data store for storing the geographical location33or the geographical location data, respectively.

An example of a user interface50is illustrated inFIG. 5. The user interface50includes a display51, e.g. an LED or LCD display, data entry elements52, e.g. individual keys or a keypad or a sensitive touch screen, and optionally some status indicators, e.g. LED's, for indicating operational states of the economizer system31. For example, the geographical location is defined by entering a postal code, e.g. a five digit ZIP code. Alternatively, the geographical location may be defined by entering coordinates or state and county names (and/or country, continent, etc.), for example. In another embodiment, the geographical location is defined using an interactive map, i.e. by selecting the geographical location, e.g. state, county, country, and/or continent, on a graphically displayed map, e.g. on a touch screen.

In the embodiments for determining automatically the geographical location by way of a receiver for a satellite-based positioning system, e.g. a GPS receiver, the geographical location data, i.e. the geographical coordinates, are determined automatically by a respective receiver included in the control device30or via a receiver interface for connecting an external receiver to the control device30. For example, the receiver interface includes a receptacle for connecting an external receiver via a wire connector. One skilled in the art will understand, that alternatively an external receiver can be connected to the control device30via a wireless interface, e.g. through Bluetooth.

The user interface50or the receiver, respectively, is controlled by a (micro-)processor of the control device30. The (micro-)processor is configured to receive and store the geographical location33or the geographical location data, respectively.

InFIG. 3, reference numeral34refers to a configuration module for determining automatically the shut-off control setting (i.e. shut-off control value) based on the geographical location33. As will be explained later in more detail with reference toFIGS. 4 and 6, the configuration module34determines the shut-off control setting based on a mapping table35stored in the control device30. The control device30includes a data store for storing the shut-off control setting37. Preferably, the configuration module34is implemented as a programmed software module, comprising computer program code for controlling the (micro-)processor of the control device30. One skilled in the art will understand, however, that, in alternative embodiments, the configuration module34can be implemented fully or partly be means of hardware elements.

In the following paragraphs, described with reference toFIGS. 4 and 6are possible sequences of steps for defining automatically for the economizer system31the shut-off control setting (i.e. shut-off control value) used as a criteria for reducing or limiting in the economizer system outdoor air intake depending on a measured outdoor air quality.

In preparatory step S1, the control device30is provided with configuration data, for example, configuration data for interoperating with a specific type of economizer system31and/or sensor type(s).

In preparatory step S11, the mapping table35is stored in control device30. As is illustrated inFIG. 6, the mapping table61is set up to map a given geographical location60to an associated shut-off control setting62(i.e. shut-off control value). Thus, the mapping table61includes geographical locations60assigned in each case to a shut-off control setting62. Preferably, the mapping table35is set up for the specific type of sensor(s) used by the economizer system31, thus there is no need to store the type of sensor(s)36) in the control device30. Alternatively, the mapping table35includes shut-off control settings for different types of sensor(s)36, which are selected based on the type of sensor(s)36stored in the control device30.

As indicated schematically inFIG. 6, in an embodiment, the mapping table61includes mapping sub-tables: a climate zone table611for mapping a given geographical location60to an associated climate zone612, and a shut-off table613for mapping a determined climate zone612to an associated shut-off control setting62. Thus, the climate zone table611includes geographical locations60assigned in each case to a climate zone612; and the shut-off table613includes climate zones612assigned in each case to a shut-off control setting62. One skilled in the art will understand, that the mapping (sub-)tables can be implemented as stored data tables or as programmed mapping functions.

As illustrated inFIG. 1for the example of the United States, climate zones are regional and divided in areas with geographical boarders.FIG. 2shows a partial table listing the climate zones in alphabetical order by state and county, for the example of the United States.

In optional preparatory step S12, the type of sensor(s)36) used by the economizer system31is stored in the control device30.

In step S2, determined and (at least temporarily) stored by the location determination module31is the geographical location where the economizer system31is installed and operated. Depending on the embodiment, in step S21, the geographical location data is entered manually through the user interface50or determined automatically in steps S22or S23, respectively. Manual entry of the geographical location data is possible before the economizer system31is actually positioned and installed at its destined location. If applicable, in step S22, the receiver of the location determination module31is activated and determines and stores the coordinates of the current location of the economizer system31. Alternatively, if applicable, in step S23, an external receiver is connected to the control device30through the receiver interface of the location determination module31, and the coordinates of the current location of the economizer system31are received by the location determination module31.

In step S3, the shut-off control setting (i.e. shut-off control value) is determined from the geographical location33determined and stored in step S2. The shut-off control setting is determined by the configuration module34using the mapping table35,61.

In an embodiment, the shut-off control setting is determined in a two-step approach using the mapping sub-tables. Thus, if applicable, in step S31, the configuration module34determines the climate zone612associated with the geographical location33from the climate zone table611. Subsequently, if applicable, in step S32, the configuration module34determines the shut-off control setting62associated with the climate zone612from the shut-off table613.

In step S33, the shut-off control setting62is stored in the control device30as the operative shut-off control setting37(i.e. shut-off control value) for the economizer system31.

It should be noted that, in the description, the computer program code has been associated with specific functional modules and the sequence of the steps has been presented in a specific order, one skilled in the art will understand, however, that the computer program code may be structured differently and that the order of at least some of the steps could be altered, without deviating from the scope of the invention.