Systems and Methods for Conditioning Unoccupied Premises

This application claims priority to and benefit of U.S. provisional patent application No. 63/646,222 filed May 13, 2024, which is herein incorporated by reference.

This disclosure relates generally to climate control systems. In particular, embodiments of the disclosure are related to preconditioning premises that have been unoccupied for long periods of time and making them suitable for occupation.

Conventional climate control systems that are used to control climate in large premises, such like office buildings, schools, etc., often have to be left running even when no one is occupying these premises for long periods of time, in order to maintain the climate within these premises. This results in a waste of energy and sub-optimal operation of the climate control system. Accordingly, systems and methods to better manage such situations without having to operate climate control systems for long periods of time in empty premises may be desired.

This disclosure relates generally to climate control systems that may be employed in commercial premises or residential units. More specifically, embodiments of the present disclosure relate to systems and methods for conditioning a facility that has been unoccupied for a period of time so that the facility is suitable for human or animal occupation.

There are many instances in which a building or a facility is left unoccupied for long periods of time. For example, a school building is often unoccupied for a long period of time during summer vacations. In some instances, hundreds of thousands of buildings may be unoccupied or sparsely occupied for multiple years. Even in the absence of any such extreme conditions, many buildings are unoccupied regularly for short periods of time. For example, office buildings are often unoccupied during a weekend. Similarly, a lot of residential premises can also be unoccupied for extended periods of time, such as during vacation or a vacation home that gets used only for a small part of the year. In these instances, the climate control systems for these facilities still need to be operational in order to ensure that the facility is in a habitable state if and when it is occupied again.

Currently, in order to maintain the habitability of such facilities, the climate control system is often continually run as if the entire facility is occupied, to maintain a set temperature within the facility and also to prevent build-up of contaminants and carbon dioxide levels within the facility. However, this results in energy waste and increases the cost of operating and maintaining the climate control system. So, there is a need for a solution that would quickly bring a facility that has been unoccupied for a while back into a habitable state without the need for continually operating the climate control system during the periods of non-occupation. The systems and methods described in this disclosure provide solutions to accomplish this, thereby resulting in energy and cost savings and prolonging the usable life of a climate control system.

In describing the disclosed technology, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

illustrates an environment in which a climate control system according to an embodiment of the present disclosure can be implemented. Facilitycan be any commercial or residential facility, such as a school, an office, a single family home, or the like. Facilitymay include a climate control systemthat is used to regulate the climate within the facility. Climate control system(or any other climate control system described herein) may broadly encompass any system that is configured to heat and/or cool a conditioned space (for example, a commercial establishment or residential building, such as a school, office building, retail establishment, warehouse, single-family home, apartment building, condominium, etc.), heat and/or cool a fluid that is provided to a load, and/or perform any other actions associated with a vapor compression cycle. Non-limiting examples of types of such climate control systems can include air conditioners (e.g., no reversing valve, only provides cooling mode), heat pumps (e.g., air source or geothermal; has a reversing valve and operates in both heating and cooling modes), heat pump water heaters, integrated heat pump water heaters, split system heat pump water heaters, heat pump water heaters with a circulation pump and a brazed plate heat exchanger, split systems, packaged systems, mini-splits, PTACs, window units, vertical packaged systems, VRF systems, etc.

In some embodiments, climate control systemmay be a residential HVAC unit. The climate control systemis in fluid communication with the facilityvia one more ducts (not shown) that carry air to and from the facility. The climate control systemis tasked with maintaining the desired temperature and other environmental parameters within the facility.

Climate control systemincludes a control unit. Control unitcan be a central control unit that controls the operation of climate control system. Control unitreceives inputs from various subsystems and components of the climate control systemand determines the mode of operation of the climate control system. Control unitmay include one or more processors, memories, and other peripheral components that together work to control operation of climate control system. Control unitmay also include a real-time clock (RTC) (not shown) or any other similar device that measures current time and/or that can be programmed to count the passage of time. In an embodiment, control unitmay be electromechanical controls or digital controls control board. Control unitmay be programmed with specialized firmware to accomplish the systems and methods described herein.

In addition to the memory that may be included in control unit, there may be one or more stand-alone memories. Memorycan be any type of non-volatile memory known in the art. Memorymay store instructions that when executed by the one or more processors of control unitenable the climate control system to perform various actions, including but not limited to the systems and methods described in this disclosure. In some embodiments, the memorymay store historical data about the operation of the climate control system and the various sensor measurements collected by sensor(s). For example, the memorymay store data regarding the last time the fan unitwas operated, sensor data measured during a specific period of time, etc.

Climate control systemmay further include one or more sensors. These sensors may include sensors that monitor one or more environmental parameters such as humidity, carbon dioxide (CO) levels, volatile organic compounds (VOC) levels, smoke, air quality, etc. Sensorsmay also include temperature, pressure, leak, and other similar types of sensors that measure the performance of climate control system. Sensorscan send their measurement data to control unitand this data may be stored for later usage in the memory. Sensorsmay be located within the facility and external to the facility. For example, a humidity or COsensor may be located inside the facility while an air quality measurement sensor may be located outside the facility or mounted to an external surface of the facility to measure the air quality of outside ambient air.

Climate control systemmay also include a communication interface. Communication interfacemay be any suitable wired or wireless communication interface known in the art. Communication interfacecan relay data from the climate control system to an external system, such as a central control system for a building or a facility. Communication interfacecan also receive data from an external system, such as a central control unit of a building that is configured to control the operation of the climate control system. In some embodiments, communication interfacemay communicate with other climate control systems within a single facility or across multiple facilities. For instance, a control server may be configured to monitor and operate multiple climate control systems and all these climate control systems may be communicably coupled to each other, such as via their individual communication interfaces.

Climate control systemmay also include a user interface. User interfacemay include a touch screen display or some other type of audio or video input and output elements that enable a user to interact with climate control system. In an embodiment, user interfacemay include one or more input mechanisms (e.g., touch screen, keyboard, microphones, camera, etc.) for inputting desired values for COlevels in the facility, humidity levels in the facility, or total volatile organic compounds (TVOC) levels in the facility. User interfacemay include one or more output mechanisms, such as display, speaker, haptics, etc. that provide some form of audio, visual or tactile output. User interfacemay be accessible from outside the facility in some embodiments.

Climate control systemmay also include one or more fans. Fan(s)controls the airflow for the climate control system. Fancan draw the air from within the facility and direct that air over one or more heat exchangers, such as evaporatoror condenser. This air is then transported to the outside of the facility depending on the operation mode of the climate control system. Another fanmay draw in the ambient outside air and direct that air over the one or more heat exchangers to either heat or cool the air based on the mode of operation of climate control system. This air is then directed to the inside of the facility. Operation of fanis well-known in the art. In some embodiments, fan, along with other components such as filters and the one or more heat exchangers, etc. may be packaged inside an air handling unit. Such an air handling unit is normally installed on the roof of the facility, basement of the facility, or within the facility and may serve one single portion or multiple portions of the facility.

Climate control systemalso includes one or more compressors. Compressorcompresses a fluid, such as a refrigerant, into a high pressure-high temperature vapor form and circulates that fluid throughout the climate control system. The fluid is ultimately returned to the compressor in a low-pressure vapor form. Compressorcan be realized using any known compressor in the art. In some embodiments, only a single compressor may be present. In other embodiments, multiple compressors, such as tandem scroll compressors, are employed for greater efficiency and reliability. The systems and methods described in this disclosure are equally applicable regardless of the number of compressors used in the climate control system.

Climate control systemmay also include an evaporator. Evaporatoris a type of heat exchanger where the refrigerant liquid is circulated and warm air is traversed across the evaporator, such as by using fan. The refrigerant liquid is converted to gas by absorbing heat from the air that is traversed over the evaporator. Evaporatorcan be realized using any known device in the art. For example, evaporatormay be an air cooled heat exchanger, shell and tube heat exchanger, plate heat exchanger, or the like.

Climate control system may also include a condenser. Condenserperforms a function that is the opposite of evaporator. Condenseris also a type of heat exchanger and may receive the refrigerant in a high-pressure gas form from the compressor and converts this gas to a slightly cooled liquid form. In an embodiment, fanmay blow cold air over condenser. The refrigerant inside the condensertransfers some of its heat to the cold air and in the process cools down. Condensercan be realized using any known device in the art. For example, condensercan be realized using an air cooled heat exchanger, shell and tube heat exchanger, plate heat exchanger, or the like.

While the evaporatorand condenserare described as separate components above, in heat pump systems, the same component may be operated as the evaporatoror condenserdepending on the operating mode of the climate control system. For example, a first heat exchanger in fluid communication with the indoor environment of the facility(e.g., placed indoors or connected to the indoors via one or more ducts) may be operated as the evaporatorin a cooling mode or the condenserin a heating mode. Likewise, a second heat exchanger in fluid communication with the outdoor environment surrounding the facility(e.g., placed outdoors or connected to the outdoors via one or more ducts) may be operated as the condenserin the cooling mode or the evaporatorin the heating mode.

Climate control system mayalso includes a thermostat. Thermostatis a control unit that is used to regulate temperature in the climate control system. Thermostatmay include a user interface via which a user can input set points for desired temperature, humidity, etc. in the facility. Depending on these set points, thermostatcan instruct other subsystems of climate control systemto perform the appropriate operation (e.g., heating, cooling, etc.). Thermostatcan be realized using any known devices in the art. In various implementations, more than one thermostatmay be positioned within the facility for establishing separate zones of climate control.

Climate control system mayalso include an economizer. The climate control system may use the economizerto ingest outdoor air into the facility instead of operating the compressor. Economizeringests outdoor air and optionally mixes it with air from indoors. This results in more efficient operation of the climate control system. Economizermay include an additional fan to help draw in the outside air. In various implementations, the economizermay be implemented as a heat recovery module (HRV) or energy recovery module (ERV) for exchanging heat and/or moisture between incoming and outgoing streams of air.

Climate control systemmay also include refrigerant linesthat carry the refrigerant throughout the system and ductworkto circulate air within the facility by transporting air from within the facility to the outside and transporting air from outside to within the facility. In various implementations, the ductworkmay include one or more dampers for differentially controlling airflow to different locations within the facility.

It is to be noted that climate control systemis just one example and other climate control systems may include more or less components than what is shown in. Although climate control systemdescribed above is akin to an Air Source Heat pump system, the systems and methods described below are equally applicable to other types of climate control systems, such as air-to-water heat pump system, ground source heat pumps, hybrid heat pumps, ductless mini-split heat pumps, absorption heat pumps, hydronic boilers, electric heaters, electric storage heaters, solar heaters, split air conditioners, etc. One skilled in the art will realize that there may be other ways to realize climate control systemwithout departing from the functionality described above.

illustrates additional details of the environment in which the climate control systemmay be deployed according to an embodiment of the present disclosure. As noted above, climate control systemmay be deployed in commercial or residential facilities. As noted above, facilitymay be a commercial facility like an office building, retail establishment, a school, or the like. In some embodiments, facilitymay be a single family home, a multi-unit dwelling, or the like. Facilitymay have one or more rooms or sections. Sensor(s)may be deployed in one or more of the rooms or sections. In some embodiments, each room or section may include all of the available sensors. In other embodiments, specific sensors may be placed at specific locations within the facility. In some embodiments, the amount and location of the sensor(s)may be governed by local building and other relevant codes. Similarly, thermostat(s)may be deployed in or more of the rooms or sections.

Facilitymay have a portion of the climate control systemmounted on the roof. In other embodiments, portions of the climate control system may be installed in the basement or one or more floors of the facility. The specific location of the climate control systemis not germane to the systems and methods disclosed herein. As shown in, climate control systemmay include an air intake unitand an air output unit. In some embodiments, air intake unitand air output unitmay each be part of an air handling unit. In some embodiments, air intake unitdraws in fresh air from outside the facility and mixes that air from within the facility. In other embodiments, the air from within the facility is not mixed with the outside air ingested by the air intake unit. In the set up illustrated in, the economizeris located within air intake unit. In some embodiments, an air quality measurement sensormay be coupled to the climate control systemto monitor the quality of the outside air. In an embodiment, the air quality measurement sensormay be an air quality index measurement sensor. Air intake unitmay have other components of the climate control system, but not all those components are shown in. The air output unitdraws air from within the facility and expels that air to the outside environment. In some embodiments, a portion of the air drawn from within the facility may be mixed with or otherwise have heat and/or moisture exchanged between the air being provided by the air intake unit. Both the air intake unitand the air output unitare in fluid communication with their respective ductworkandin order to supply air to and draw air from within the facility as is shown by the directional arrows in.

In operation, whenever fresh air from outside is needed, economizermay operate in conjunction with fanto draw the outside air and optionally mix it with the inside air in order to implement the conditioning systems and methods mentioned in this disclosure, to remove the stagnant air from within the facilityand replace it with fresh air from outside the facility. The following figures and description will provide the details of these various systems and methods.

is a block diagram of a portion of a climate control systemaccording to an embodiment of the present disclosure. Climate control systemmay be similar to climate control systemdescribed above.

Climate control systemincludes control unit. Control unitmay include one or more processors or controllers that control the operation of the climate control system. The one or more processors or controllers may be programmed with custom firmware that executes the functions described below. Climate control systemincludes a heating subsystemthat may include several components and is functional to provide heating to the facility. Heating subsystemmay include a fan, one or more heat exchangers, and a compressor and associated refrigerant lines. Climate control systemfurther includes a cooling subsystemthat may include several components and is functional to provide cooling to the facility. For example, cooling subsystemmay include a compressor, a fan, one or more heat exchangers, and associated refrigerant lines. Heating subsystemand cooling subsystemmay also share some components, such as one or more compressors, one or more heat exchangers in a heat pump system, etc. In an embodiment, fan(s)may be part of the heating subsystemor the cooling subsystem. Control unitis electrically coupled to both heating subsystemand the cooling subsystemand controls the operation of these two subsystems.

Control unitis also electrically coupled to the economizer. As described above, economizeris in fluid communication with the ambient environment via one or more ducts. When economizeris activated, it draws in ambient air from outside the facility and mixed it with air from within the facility. The operation of economizeris controlled by the control unit. Control unitis also electrically coupled to the thermostat. Thermostatallows an operator to set temperature and other set points. This set point information is provided to the control unit, which then operates either the heating subsystemor the cooling subsystemin order to achieve the temperature set point.

Control unitis also electrically coupled to the sensor(s). A particular facility may employ multiple sensors that each measure some specific parameter of the environment within the facility or external to the facility. As described above, sensor(s)may include CO, humidity, VOC, smoke, air quality, and other similar sensors. Sensorsare configured to send their respective measurement data to the control unit. Sensorsmay send the measurement data periodically or on demand. In an embodiment, sensorsmay be Internet of Things (IoT) based sensors that can communicate wirelessly with control unit.

In an embodiment, control unitreceives input from sensorsand thermostatand based on those inputs controls operation of the climate control systemin order to maintain the facility in a habitable state. The different methods of conditioning the environment within the facility after a prolonged time of non-occupation are described below in relation to.

illustrates a flow chart for a processfor operating a climate control system (e.g., climate control systemof, or) according to an embodiment of the present disclosure. The following description will be provided with reference to both.

As described above, certain facilities may remain unoccupied for extended periods of time. For example, a school building may remain unoccupied for the entire duration of summer holidays. Normally, the climate control system of such a facility may be left on or run periodically using a set schedule, such as daily or weekly, in order to maintain the habitability of the building. However, in order to conserve energy and lower costs, the climate control system of such a facility may be turned off or kept idle during that non-occupation time period. While turning off the climate the control system may save money, undesirable environmental conditions such as humidity, COlevel, or VOC levels may increase within this facility since the air within the facility is sitting stagnant for an extended period of time. Before such facility is cleared for human occupation, it is desirable that the stagnant air within this facility be removed and replaced with fresh air and the various environment parameters be brought within their respective acceptable ranges. In other words, a conditioning of the facility may be needed in order to maintain the facility habitable. If the climate control system has been idle or non-working for an extended period of time, it may take a long while before the facility can be made habitable again once the climate control system is made operational. Currently, the climate control system of such a facility is kept active continually to avoid the long recovery time that may be needed. So, in many instances, the climate control system is heating or cooling an empty facility. To avoid the issues caused by continually running the climate control system or completely shutting down the climate control system for long periods of time, the systems and methods disclosed herein provide an alternative that is cost effective to operate, saves energy, and may prolong the usable life of the climate control system.

illustrates a processfor conditioning of the facility according to an embodiment of the present disclosure. Conditioning as used herein refers to the process of replacing the stagnant air within a facility that has been unoccupied for a while, with fresh air and to ensure that the environmental parameters, such as temperature, humidity, TVOC levels, COlevels, etc. within the facility are within their respective acceptable ranges as described above. At operation, processmay be activated. Activation of processmay be manual or automatic depending on the status of one or more parameters. At operation, the climate control systemdetermines the amount of time elapsed since the last operation of the system. For example, climate control systemmay determine the time elapsed since the last time the fan was operated. Other criteria for “last operation” may also be used and an operator of climate control systemcan decide what criteria is to be used. In an embodiment, the RTC in control unitmay be used to determine the amount of time elapsed since the last operation of the climate control system. In another embodiment, the timer in control unitmay be used to keep track of elapsed time since last operation. In some embodiments, the operator of climate control systemmay configure the maximum amount of time that climate control systemis allowed to remain idle/turned off. For example, the operator may set X hours or X days or any other suitable measure as the maximum duration for which climate control systemis allowed to be idle/turned off. In other embodiments, this time value may be hard-coded into the system.

At operation, the climate control systemdetermines whether the time elapsed since the last operation of the climate control systemexceeds the set value. If the time elapsed since the last operation of the climate control systemdoes not exceed the set value, processreturns to operationand the time monitoring continues. If it is determined that the time elapsed since the last operation of the climate control systemexceeds the set time value, processproceeds to operation. It is to be noted that time elapsed since the last operation is not the only parameter that can be used to trigger the following operations. Other parameters in lieu of or in addition to time elapsed can also be used to trigger the operations. For example, time of the day, day of the week, time before scheduled re-occupation of the facility, presence of humans in the facility, etc. may also be used. In other embodiments, if one or more of the environmental parameters are found to be out of their respective acceptable ranges based on the sensor data, the climate control system may initiate the process. Time elapsed since the last operation of climate control systemis used herein just for the sake of explanation and the systems and methods described herein are not limited to use of this parameter only.

At operation, the climate control systemreceives data from the one or more environment sensors, such as sensorsof. This data is compared against a threshold value for each of the respective parameters. As explained above, various types of environmental sensors may be used in the system. For example, the system may use a carbon dioxide (CO) sensor. The acceptable carbon dioxide levels for a habitable facility is prescribed by the relevant building code based on the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards. In one embodiment, the maximum acceptable indoor carbon dioxide levels are between 1000 ppm and 1500 ppm. It is to be noted that the range specifies the upper limit of the level of carbon dioxide. So, as long as the levels of carbon dioxide are lower than 1500, it can be considered to be acceptable. In this instance, the data received from the carbon dioxide sensor is analyzed to determine whether the data is within the acceptable range. In case of a humidity sensor, the acceptable indoor humidity may be in the range of 40% to 60%. Therefore, data received from a humidity sensor is compared against this range. In the instance where total volatile organic compounds (TVOC) are being monitored, the following Table 1 below may be used to determine whether the data received from the TVOC sensor(s) are within the level of acceptable values for VOCs. In one instance, the acceptable TVOC levels may be prescribed by one or more industry organization or standards such as Occupational Safety and Health Administration (OSHA), Leadership in Energy and Environmental Design (LEED), World health Organization (WHO), etc. In Table 1 below, the “Description” column generally describes the quality of the environment inside the facility in a textual form that is easy to understand. “Index value” refers to the TVOC index that is commonly known in the art. The final column “TVOC (ppb*)” includes values that are represented in parts per billion (ppb) and refers to amount of VOC particulate matter in a given space. Total volatile organic compounds (TVOC) is a group of VOCs used to represent the entire pool of pollutants.

It is to be noted that the acceptable levels of the environmental parameters may vary according to the geographic location, as different countries may have different standards. The ranges and values provided above in Table 1 are just one example of what the acceptable levels may be and should not be construed as binding or the only acceptable values.

In some embodiments, prior to receiving the sensor values at operation, the climate control systemmay turn on a fan associated with the climate control systemfor a specified period of time to circulate the indoor air. Once the fan has been operated for the specified period of time, control unitmay receive the data from the sensors. In some embodiments, control unitmay be programmed to “pull” data from the sensors after expiry of the specified period of time. In other embodiments, the sensors may be instructed to send their data at a specific time which coincides with the expiry of the specified period of time. This specified period of time may be hard-coded into the system or may be user-programmable. This specified period of time is usually lower than the period of time for which the climate control systemis allowed to remain idle/non-operational as explained with relation to operationsandabove.

At operation, climate control systemanalyzes the data received in operationto determine whether data from one or more of the sensors indicates that the corresponding environmental parameter is out of range. For example, data from a carbon dioxide sensor might indicate that the level of carbon dioxide within a portion of the facility or even within the entire facility is higher than the maximum acceptable value described above. Alternatively, data from the carbon dioxide sensor may indicate that the level of carbon dioxide in the facility are lower than the maximum acceptable value. If at operation, the control unit determines that all of the sensors indicate that the respective parameters are within their respective acceptable ranges, processmay return to operation(or optionally to operation) and continue receiving sensor data and comparing that against the respective thresholds.

If at operation, the control unit determines that one or more sensors indicate that the corresponding environmental parameter is higher than the respective acceptable range, the system may proceed to operation. The climate control systemmay be programmed in multiple ways to interpret and react to the data provided by the sensors. For example, the system may be programmed such that even if a single sensor indicates that a single environmental factor is higher than the corresponding acceptable range, system may execute operation. For instance, even if only the COsensor may indicate that the indoor COvalue is higher than the acceptable range while the TVOC and humidity sensors may indicate values within their respective acceptable ranges, the system may proceed to operation. In other embodiments, the system may be programmed to proceed to operationonly if two or more sensors show that their data indicates that the environmental parameters are higher than their corresponding acceptable ranges. One skilled in the art will realize that there are many more ways of programming the system to act based on several different combinations of the sensor data. All of these different combinations are within the scope of this disclosure, but are not explicitly described herein for sake of brevity.

Once it is determined that one or more sensors indicate that the corresponding environment parameter is out of acceptable range, the climate control system may operate to ingest air from outside the facility at operation. In one embodiment, the control unit of the climate control system may operate economizerto facilitate flow of outside air into the facility. Economizer may turn on an associated fan, open the dampers, and draw in ambient air from outside the facility. This outside air is then optionally mixed with the indoor air and then recirculated within the facility. Other portions of the climate control system may also be activated to work in conjunction with the economizer to continually circulate the outside air within the facility and remove the stagnant from within the facility. In due course, the environmental parameters may slowly start to return to acceptable levels.

Once the outside air is ingested at operation, the system may monitor the temperature set point for the facility at operation. In one embodiment, the operator of the facility may designate an indoor temperature set point for the facility when the facility is unoccupied. In one instance, this temperature set point may be lower than the temperature set point when the facility is occupied. For example, the temperature set point for an unoccupied facility may be set at 60° F. while the temperature set point for that same facility when it is occupied may be set at 68° F. These temperature set points may vary based on geographic area and the average outside ambient temperature patterns in that geographic area. As the outside air is ingested into the facility the temperature inside the facility may rise or fall depending on the temperature of the ambient outside air. The climate control system continually monitors the current temperature inside the facility, at operation, and compares that to the current temperature set point.

At operation, the system determines whether the current temperature within the facility is higher or lower than the temperature set point. If the current temperature is higher than the temperature set point, the system may initiate a cooling operation at operation, such as by operating the cooling subsystem. If the current temperature is lower than the temperature set point, the system may initiate a heating operation at operation, such as by operating the heating subsystem. The processmay repeat until all the environmental parameters are within their respective acceptable ranges and the indoor temperature is substantially equal (e.g., within +−5%) to the temperature set point. Optionally, after starting the cooling operation at operationor the heating operation at operation, the climate control system may cease operation of the economizer and stop ingesting outside ambient air. Whether to stop the operation of the economizer may depend on several factors including the current levels of environmental parameters as measured by the one or more environmental sensors.

Further, after initiating cooling operation at operationor heating operation at operation, processmay return to operationand continue monitoring the various sensors to determine whether the corresponding environmental parameters are within the acceptable ranges. If the values of the environmental parameters are still out of range, the system may continue to ingest outside air (operation) and the process is repeated until one or more of the environmental parameters come within their acceptable range. Once the sensors indicate that the environmental parameters are within the respective acceptable ranges, the climate control systemmay stop ingesting the outside air. In this manner, the system ensures that the facility is always ready to be occupied and the environment within the facility does not become hazardous.

illustrates a processfor operating a climate control system according to another embodiment of the present disclosure. Processmay be performed, for example, by climate control systemof.

At operation, processmay be triggered, such as based one or more criteria explained above with reference to. At operation, the climate control system determines an amount of time elapsed since the last operation of the climate control system. As explained above, this is just one of the many parameters that can be used to trigger process. At operation, the climate control system determines whether the time elapsed since the last operation is more or less than a threshold value. The time elapsed value may be measured in minutes, hours, days, weeks, or months. The threshold value is also set accordingly. In an embodiment, the threshold value may be set by the user based on the usage pattern or usage history of the facility. In other embodiments, the threshold value may be dynamically adjusted based on the outside ambient temperature. For example, consider that initially the threshold time setting for time elapsed since the last operation is set at two days. A current time indicates that it has been less than two days since the last operation, so processshould not be triggered. However, outside ambient temperature data indicates that the outside ambient temperature exceeds a threshold, such as 100° F. In this instance, the system may dynamically modify the threshold time setting such that processis initiated before the expiration of two days since the last operation. Thus, the outside ambient temperature may be used to trigger the processeven if the result of the check at operationis a ‘no.’ Similarly, other events may be used to trigger processeven if the results of the check at operationindicate that the processshould not move forward beyond operation.

If at operation, it is determined that the time elapsed since the last operation is less than the threshold value, the climate control system stays in its current mode and processreturns to operationand continues counting the time elapsed, such as by using the RTC in the control unit, as explained above. As soon as the climate control system determines that the time elapsed since the last operation is equal to or greater than the threshold value (or is otherwise triggered by other events described above), processmay move to the next operation. As described above, in some embodiments, prior to moving on to operation, the climate control system may operate a fan for a specified period of time after determining that the time elapsed since the last operation is more than the threshold value.

At operation, the data received from one or more of the environmental parameter sensors is analyzed by the climate control system. In some embodiments, the data from the sensors may only be requested after the determination in operationthat the time elapsed since the last operation is more than the threshold value. In other embodiments, the sensors may be programmed to continually or periodically send their data to the control unit. This data may be saved in a circular buffer where the most recent values overwrite the oldest value. Then, once the determination is made in operationthat the time elapsed since the last operation is more than the threshold value, the most recent values in the buffer are read and compared against the respective thresholds. One skilled in the art will realize that there are many other ways to implement this operation.

Once the most recent data from the one or more sensors is received at operation, processproceeds to compare the data with the respective thresholds or ranges at operation. If the sensor data indicates that the environment parameters are within their respective acceptable ranges or below the thresholds, processmay return to operationor optionally to operationand continue monitoring the sensor data. It is to be noted that in this case, even if the time elapsed since the last operation is more than the threshold value, the system may still remain in its current idle state since the environmental parameters are within range. Thus, the system may be programmed to prioritize to operate the economizer only if one or more environmental parameters exceeds the respective threshold.