Abstract: A system and method for encrypting communication for networked heating, ventilation, and air conditioning (HVAC) devices. A method includes obtaining a list of network devices of a network, requesting a certificate for each network device in the list of network devices of the network, and generating a shared symmetric key for encrypting communication in the network. A method may also include encrypting the shared symmetric key with a public key for each network device in the list of network devices having a valid certificate, transmitting the encrypted shared symmetric key with each network device having a valid certificate, each network device includes a different certificate, and communicating between the master device and the network device using the shared symmetric key.

Abstract: A central controller for an intelligent environmental air management system includes at least one processor and memory storing instructions executable by the at least one processor. The instructions, when executed, cause the central controller to detect and communicate with an air hazard sensor, an environmental condition monitor, and an air hazard mitigation device of the intelligent environmental air management system.

Abstract: A refrigeration system including a first compressor and a second compressor, operating in tandem, wherein the first compressor includes a compression capacity different than the compression capacity of the second compressor. A method for operating a refrigeration system including a first compressor and a second compressor operating in tandem; wherein the first compressor comprises a first compression capacity and the second compressor comprises a second compression capacity larger than the first compression capacity the method comprising the steps of: determining a cooling demand; operating the first compressor in a first stage of cooling; operating the second compressor in a second stage of cooling; and operating the first compressor and the second compressor in a third stage of cooling.

Abstract: A refrigeration system including a first compressor and a second compressor, operating in tandem, wherein the first compressor includes a compression capacity different than the compression capacity of the second compressor. A method for operating a refrigeration system including a first compressor and a second compressor operating in tandem; wherein the first compressor comprises a first compression capacity and the second compressor comprises a second compression capacity larger than the first compression capacity the method comprising the steps of: determining a cooling demand; operating the first compressor in a first stage of cooling; operating the second compressor in a second stage of cooling; and operating the first compressor and the second compressor in a third stage of cooling.