Retrieve device serial number if possible
I have found the device serial numbers for my ACs are avilable in the payload in devices array.
For RAC_056905_WW, the serial number could be obtained from 
https://eic-service.lgthinq.com:46030/v1/service/homes/{homeId}
located at `devices.manufacture.serialNo` in the JSON response.

I think `devices.manufacture. salesModel` would be better for model than model name of RAC_056905 as that's the marketing model and used on the AC packaging.