Abstract: An example refrigeration system includes an indoor fluid loop, an outdoor fluid loop, and a heat exchanger assembly. The indoor fluid loop circulates a first working fluid. The outdoor fluid loop circulates a second working fluid that is different from the first working fluid and is separated from the indoor fluid loop by a wall of a structure. The heat exchanger assembly is mounted within the wall of the structure. The heat exchanger assembly includes a heat exchanger and a housing, where the heat exchanger is disposed within an internal space defined by the housing. The housing supports the heat exchanger within the internal space and is mounted to a structure of the wall.

Abstract: A heat-pump system may include a compressor, an outdoor heating exchanger, an indoor heat exchanger, an expansion device, and a supplemental heater. The outdoor heat exchanger may be in fluid communication with the compressor. The indoor heat exchanger may be in fluid communication with the compressor. The expansion device may be in fluid communication with the indoor and outdoor heat exchangers. The supplemental heater may include a burner and a working-fluid conduit. The burner may be configured to burn a fuel and heat the working-fluid conduit. When the heat-pump system is operating in a heating mode, the indoor heat exchanger may receive working fluid from the working-fluid conduit such that the working fluid flows from an outlet of the working-fluid conduit to an inlet of the indoor heat exchanger.

Abstract: First and second IAQ sensors are located within a building and are configured to measure first and second IAQ parameters, respectively, the first and second IAQ parameter being the same one of: relative humidity; amount of particulate; amount of volatile organic compounds; and amount of carbon dioxide. A mitigation device is separate from an HVAC system and includes a control module configured to turn the mitigation device on and off based on the first IAQ parameter, the second IAQ parameter, and whether the HVAC system is on or off. A mitigation module is configured to selectively turn the HVAC system on and off based on the second IAQ parameter, the first IAQ parameter, and whether the HVAC system is on or off.

Abstract: A control system for a mitigation device includes a processor and a computer-readable medium that includes instructions executable by the processor. The instructions include monitoring a first measured particulate matter (PM) level of a conditioned space. The first measured PM level includes PM having a first range of sizes. The instructions further include monitoring a second measured PM level of the conditioned space. The second measured PM level includes PM having a second range of sizes. The first and second ranges are different but overlapping. The instructions also include asserting, in response to the first measured PM level being greater than a first predetermined threshold, an activation signal. The activation signal forces operation of a fan of the mitigation device. The instructions include asserting, in response to the second measured PM level being greater than a predetermined percentage of the first measured PM level, the activation signal.

Abstract: A refrigerant measurement adjustment system includes: a refrigerant sensor for a building and configured to measure an amount of refrigerant present in air outside of a refrigeration system of the building; and an adjustment module configured to: adjust the amount of refrigerant measured based on an adjustment to produce an adjusted amount; and determine the adjustment based on at least one of: an air temperature; an air pressure; a relative humidity of air; a mode of operation of the refrigeration system; a change in the measurements of the refrigerant sensor over time; and whether a blower that blows air across a heat exchanger of the refrigeration system located within the building is on.

Abstract: A refrigerant control system includes: a reversing valve including: a first inlet configured to receive refrigerant output from a condenser; a first outlet configured to output refrigerant to an inlet of an evaporator located inside of a building; a second inlet configured to receive refrigerant output from the evaporator; and a second outlet configured to output refrigerant to an inlet of a compressor that pumps refrigerant to the condenser; a reversing module configured to: selectively actuate the reversing valve to a first position such that: refrigerant flows directly from the second inlet to the second outlet; and refrigerant flows directly from the first inlet to the first outlet; and selectively actuate the reversing valve to a second position such that: refrigerant flows directly from the second inlet to the first outlet; and refrigerant flows directly from the first inlet to the second outlet.

Abstract: A system for charging an outdoor unit with refrigerant includes a sensor configured to measure a refrigerant concentration and a user device configured to receive the measured refrigerant concentration. The system includes that the user device is configured to, in response to the measured refrigerant concentration exceeding a threshold, generate and display an alert on a user interface of the user device indicating the measured refrigerant concentration exceeds the threshold.

Abstract: A refrigeration system of a building includes: a compressor module configured to, in response to a determination that an amount of a refrigerant of the refrigeration system that is present outside of the refrigeration system and within the building is greater than a first predetermined amount, maintain a compressor off continuously for a predetermined period; and a fan module configured to, in response to the determination, maintain a fan on continuously for at least the predetermined period, and where the compressor module is further configured to, without receiving input indicative of a reset of the refrigeration system, after the compressor has been off for the predetermined period and the amount of refrigerant that is present outside of the refrigeration system within the building is less than a second predetermined amount, selectively turn the compressor on.

Abstract: A condition identification module is configured to, based on output from the at least one of a microphone and a camera, indicate an occurrence of a user having a physical condition. A correlation module is configured to, based on the occurrence of the user having the physical condition and at least one of a temperature of air, a relative humidity of air, an amount of particulate of at least a predetermined size present in air, an amount of VOCs present in air, and an amount of carbon dioxide present in air, selectively identify the presence of a correlation between the occurrence of the user having the physical condition and the at least one of the temperature, the RH, the amount of particulate, the amount of VOCs, and the amount of carbon dioxide.

Abstract: A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a refrigeration system of a building; a leak module configured to diagnose that a leak is present in the refrigeration system based on the amount of refrigerant; and at least one module configured to take at least one remedial action in response to the diagnosis that the leak is present in the refrigeration system.

Abstract: A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a first portion of a refrigeration system within a building; and an isolation module configured to selectively open and close an isolation valve of the refrigeration system and to, via the isolation valve, maintain the amount of refrigerant within the first portion within the building below a predetermined amount of the refrigerant.

Abstract: A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a refrigeration system of a building; a leak module configured to diagnose that a leak is present in the refrigeration system based on the amount of refrigerant; and at least one module configured to take at least one remedial action in response to the diagnosis that the leak is present in the refrigeration system.

Abstract: First and second IAQ sensors are located within a building and are configured to measure first and second IAQ parameters, respectively, the first and second IAQ parameter being the same one of: relative humidity; amount of particulate; amount of volatile organic compounds; and amount of carbon dioxide. A mitigation device is separate from an HVAC system and includes a control module configured to turn the mitigation device on and off based on the first IAQ parameter, the second IAQ parameter, and whether the HVAC system is on or off. A mitigation module is configured to selectively turn the HVAC system on and off based on the second IAQ parameter, the first IAQ parameter, and whether the HVAC system is on or off.

Abstract: A control system for a mitigation device includes a processor and a computer-readable medium that includes instructions executable by the processor. The instructions include monitoring a first measured particulate matter (PM) level of a conditioned space. The first measured PM level includes PM having a first range of sizes. The instructions further include monitoring a second measured PM level of the conditioned space. The second measured PM level includes PM having a second range of sizes. The first and second ranges are different but overlapping. The instructions also include asserting, in response to the first measured PM level being greater than a first predetermined threshold, an activation signal. The activation signal forces operation of a fan of the mitigation device. The instructions include asserting, in response to the second measured PM level being greater than a predetermined percentage of the first measured PM level, the activation signal.

Abstract: An indoor air quality (IAQ) system for a building includes an IAQ sensor that is located within the building and that is configured to measure an IAQ parameter. The IAQ parameter is one of: an amount of particulate of at least a predetermined size present in air; an amount of volatile organic compounds (VOCs) present in air; and an amount of carbon dioxide present in air. A mitigation module is configured to: selectively turn on a mitigation device based on a comparison of the IAQ parameter with a first ON threshold and a second ON threshold; and selectively turn off the mitigation device based on a comparison of the IAQ parameter with an OFF threshold. A clean module is configured to determine a clean value for the IAQ parameter. A thresholds module is configured to, based on the clean value, determine the first ON threshold and the OFF threshold.

Abstract: An indoor air quality (IAQ) system for a building includes an IAQ sensor that is located within the building and that is configured to measure an IAQ parameter, the IAQ parameter being one of: a relative humidity (RH) of air; an amount of particulate of at least a predetermined size present in air; an amount of volatile organic compounds (VOCs) present in air; and an amount of carbon dioxide present in air. A mitigation module is configured to: selectively turn on a mitigation device based on a comparison of the IAQ parameter with a first threshold; and selectively turn off the mitigation device based on a comparison of the IAQ parameter with a second threshold. A thresholds module is configured to: set the first and second thresholds to predetermined default values; and selectively adjust at least one of the first and second thresholds.

Abstract: A heating, ventilation, and air conditioning (HVAC) control system generates a request to replace a first air filter installed in an air handler of an HVAC system with a second air filter. The second air filter has a particulate matter removal efficiency rating that is greater than a particulate matter removal efficiency rating of the first filter. The system delays for a predetermined period of time and then obtains (i) a first temperature of air downstream of the air handler and (ii) a second temperature of air upstream of the air handler. The system then calculates a temperature difference between the f temperatures and determines whether the temperature difference is within an acceptable range. In response to the temperature difference being within the acceptable range, the system (i) operates the HVAC system using the second air filter and (ii) generates an alert indicating compatibility of the second air filter.

Abstract: An IAQ sensor module includes: a sensor configured to measure an amount of an item in air, the item being one of particulate matter, volatile organic compounds, and carbon dioxide; a minimum module configured to selectively store the amount of the item as a minimum value of the amount when a mitigation device has been on for at least a predetermined period, the mitigation device being configured to decrease the amount of the item in the air when on; a storing module configured to selectively store the minimum value as an initial minimum value; an offset module configured to determine a drift offset for the sensor based on a difference between the minimum value and the initial minimum value; and an adjustment module configured to determine an adjusted amount of the item in the air at the IAQ sensor module based on the amount and the drift offset.

Abstract: A condition identification module is configured to, based on output from the at least one of a microphone and a camera, indicate an occurrence of a user having a physical condition. A correlation module is configured to, based on the occurrence of the user having the physical condition and at least one of a temperature of air, a relative humidity of air, an amount of particulate of at least a predetermined size present in air, an amount of VOCs present in air, and an amount of carbon dioxide present in air, selectively identify the presence of a correlation between the occurrence of the user having the physical condition and the at least one of the temperature, the RH, the amount of particulate, the amount of VOCs, and the amount of carbon dioxide.

Abstract: An indoor air quality (IAQ) system for a building includes an IAQ sensor that is located within the building and that is configured to measure an IAQ parameter. The IAQ parameter is one of: an amount of particulate of at least a predetermined size present in air; an amount of volatile organic compounds (VOCs) present in air; and an amount of carbon dioxide present in air. A mitigation module is configured to: selectively turn on a mitigation device based on a comparison of the IAQ parameter with a first ON threshold and a second ON threshold; and selectively turn off the mitigation device based on a comparison of the IAQ parameter with an OFF threshold. A clean module is configured to determine a clean value for the IAQ parameter. A thresholds module is configured to, based on the clean value, determine the first ON threshold and the OFF threshold.