Controlling air conditioning systems
Air conditioning systems and processes may monitor properties of the system and/or properties related to the system. The air conditioning system may allow operation based on user requests and/or allow stress operation(s) based on monitored properties.
1. An HVAC system comprising:
a controller;
an evaporator;
a condenser:
one or more compressors;
a plurality of sensors, including at least one pressure sensor, the plurality of sensors capable of detecting a stress event, the stress event comprising operating a portion of the HVAC system with a refrigerant pressure above a predetermined pressure value for the portion of the HVAC system; and
a stress module communicatively coupled to the plurality of sensors and to the controller;
wherein the stress module is operable, in response to the controller receiving a request for an operation of the HVAC system, to:
determine whether to allow the operation based at least in part on detecting the stress event;
restrict the requested operation if the stress module determines to not allow the operation;
identify at least one stress operation to allow based in part on a measured pressure at the at least one pressure sensor exceeding the predetermined pressure value for the portion of the HVAC system, if the operation is restricted; and
allow at least one stress operation based on the identification, wherein the at least one stress operation comprises adjusting a refrigerant flow rate;
wherein:
the identification of one or more stress operations to allow by the stress module is further based on tracking a trip count comprising a number of times the measured pressure exceeds the threshold and whether the trip count exceeds a predetermined trip count; and
the at least one stress operation further comprises performing at least one safe mode operation if the trip count exceeds the predetermined trip count, wherein the at least one safe mode operation comprises at least one of:
allowing a respective compressor of the one or more compressors to operate at a low stage, wherein the respective compressor comprises a high stage and at least one low stage; or
allowing operation of one compressor of the one or more compressors and restricting operation of another compressor of the one or more compressors.
2. The HVAC system of claim 1 , further comprising:
a thermal expansion valve;
a heat transfer element coupled to the thermal expansion valve; and
a processor that delivers signals to control the heat transfer element to deliver heat to a bulb of the thermal expansion valve;
wherein an opening through the thermal expansion valve is adjustable in response to the heat delivered to the bulb.
3. The HVAC system of claim 1 , further comprising at least one of:
a blower having at least one high stage and a low stage; or
a controllable thermal expansion valve.
4. The HVAC system of claim 1 , wherein the at least one stress operation further comprises adjusting a blower operation.
5. The HVAC system of claim 1 , wherein:
the identification of one or more stress operations to allow by the stress module is further based in part on a measured ambient temperature exceeding a predetermined temperature; and
the at least one stress operation further comprises operating a blower of the HVAC system at a high stage, wherein the blower of the air HVAC system comprises at least one high stage and one low stage.
6. The HVAC system of claim 1 , wherein:
the identification of one or more stress operations to allow by the stress module is further based on a measured pressure of the refrigerant at the at least one pressure sensor exceeding the predetermined pressure less than approximately ten seconds after startup of one or more compressors of the HVAC system; and
the at least one stress operation further comprises:
restricting operation of one or more of the one or more compressors if the pressure of the refrigerant is determined to exceed the predetermined pressure; and
performing one or more slugging inhibition operations, wherein the one or more slugging inhibition operations comprise at least one of: operating a blower of the HVAC system for one or more periods of time or adjusting an amount of refrigerant allowed to pass through a thermal expansion valve of the HVAC system.
7. An HVAC system comprising:
a controller;
an evaporator;
a condenser;
a thermal expansion valve;
a blower;
one or more compressors;
a plurality of sensors, including at least one pressure sensor, the plurality of sensors capable of detecting a stress event, the stress event comprising operating a portion of the HVAC system with a refrigerant pressure above a predetermined pressure value for the portion of the HVAC system; and
a stress module communicatively coupled to the plurality of sensors and to the controller;
wherein the stress module is operable, in response to the controller receiving a request for an operation of the HVAC system, to:
determine whether to allow the operation based at least in part on detecting the stress event;
restrict the requested operation if the stress module determines to not allow the operation;
identify at least one stress operation to allow based in part on a measured pressure at the at least one pressure sensor exceeding the predetermined pressure value for the portion of the HVAC system, if the operation is restricted; and
allow at least one stress operation based on the identification, wherein the at least one stress operation comprises adjusting a refrigerant flow rate; and
wherein:
the identification of one or more stress operations to allow by the stress module is further based on a measured pressure of the refrigerant at the at least one pressure sensor exceeding the predetermined pressure less than approximately ten seconds after startup of one or more compressors of the HVAC system; and
the at least one stress operation further comprises:
restricting operation of one or more of the one or more compressors if the pressure of the refrigerant is determined to exceed the predetermined pressure; and
performing one or more slugging inhibition operations, wherein the one or more slugging inhibition operations comprise at least one of: operating the blower for one or more periods of time or adjusting an amount of refrigerant allowed to pass through the thermal expansion valve.
8. The HVAC system of claim 7 , further comprising:
a heat transfer element coupled to the thermal expansion valve; and
a processor that delivers signals to control the heat transfer element to deliver heat to a bulb of the thermal expansion valve;
wherein an opening through the thermal expansion valve is adjustable in response to the heat delivered to the bulb.
9. The HVAC system of claim 7 , further comprising at least one of:
a blower having at least one high stage and a low stage; or
a compressor having a high stage and at least one low stage.
10. The HVAC system of claim 7 , wherein the at least one stress operation further comprises adjusting a blower operation.
11. The HVAC system of claim 7 , wherein:
the identification of one or more stress operations to allow by the stress module is further based in part on a measured ambient temperature exceeding a predetermined temperature; and
the at least one stress operation further comprises operating the blower at a high stage, wherein the blower comprises at least one high stage and one low stage.