Abstract: A vapor compression system includes an indoor heat exchanger, an outdoor heat exchanger, a compressor, a first valve, and a second valve. The compressor has an inlet connected to a suction flow and an exit connected to a discharge flow. The first valve is movable to connect the discharge flow to one of the indoor and outdoor heat exchangers. The second valve is movable to connect the suction flow to one of the indoor and outdoor heat exchangers.

Abstract: A method of HVAC system performance monitoring using a computing device connected to at least one thermostat of an HVAC system in a building includes receiving thermostat data from the thermostat, the thermostat data including temperature setpoint data, measured building temperature data, and HVAC operation data for a time period. Weather data is received from a weather service for the time period, and the thermostat data is synchronized with the weather data with respect to time. At least one machine learning model is trained using the synchronized thermostat and weather data, and performance of the HVAC system over time is monitored using the trained machine learning model.