A method of operating an air conditioner unit, as provided herein, includes initiating a first heat pump cycle, the first heat pump cycle comprising sending a control signal to the fan to rotate at a predetermined rotational speed, and detecting an actual rotational speed of the fan, calculating a first flow rate of air through the first heat exchanger based on the control signal and the actual rotational speed, storing the first flow rate as a first reference flow rate, stopping the first heat pump cycle, initiating a second heat pump cycle, calculating a second flow rate of air through the first heat exchanger, comparing the calculated second flow rate to the first reference flow rate, and directing the air conditioner unit based on the comparison of the calculated second flow rate to the first reference flow rate.

A method of operating an air conditioner unit, as provided herein, includes initiating a first heat pump cycle, the first heat pump cycle comprising sending a control signal to the fan to rotate at a predetermined rotational speed, and detecting an actual rotational speed of the fan, calculating a first flow rate of air through the first heat exchanger based on the control signal and the actual rotational speed, storing the first flow rate as a first reference flow rate, stopping the first heat pump cycle, initiating a second heat pump cycle, calculating a second flow rate of air through the first heat exchanger, comparing the calculated second flow rate to the first reference flow rate, and directing the air conditioner unit based on the comparison of the calculated second flow rate to the first reference flow rate.

A method of maintaining a fluid flow rate in a heating, ventilating, air conditioning, and refrigeration (HVAC-R) system while maintaining superheat in the HVAC-R system at a desired level includes: continuously measuring an operating fluid temperature of the HVAC-R system and calculating superheat at a pre-determined rate, determining if the calculated superheat is stable, measuring and recording an operating fluid pressure of the system each time the calculated superheat is stable, recording an average operating fluid pressure each subsequent time the superheat is stable, calculating an output PWM and reducing fluid flow through a metering valve when an actual PWM is greater than the calculated output PWM by adjusting a PWM signal to a microvalve in the metering valve, and increasing fluid flow through the metering valve when the actual PWM is less than the calculated output PWM by adjusting the PWM signal to the microvalve.

A system for cooling a refrigerant includes (a) an evaporator comprising one or more lengths of tubing each having an upstream first cross-sectional area and a second downstream cross-sectional area, the second cross-sectional area being greater than the first cross-sectional area, the expansion in cross-sectional area between the first circular cross-sectional area and the second circular cross-sectional area being smooth and continuous; and (b) a compressor and a condenser for converting the refrigerant from a gas to a liquid for introduction into the evaporator.

Provided is a temperature-adjusting fluid supply apparatus that causes a fluid for temperature adjustment to be circulated between a heat exchanger that transfers heat supplied from a refrigerant to the fluid, and an object to be adjusted for temperature that uses the heat of the fluid, the temperature-adjusting fluid supply apparatus being able to prevent the fluid from freezing. A temperature-adjusting fluid supply apparatus is provided with a heat exchanger that transfers heat supplied from a refrigerant to a fluid for temperature adjustment, a supply tube through which the fluid flows from the heat exchanger toward an object to be adjusted for temperature, a return tube through which the fluid returning from the object to be adjusted for temperature flows, a flow rate adjustable pump, a flow sensor, a flow switch, a temperature sensor, and a control part. The flow switch, in comparison with the flow sensor, is able to detect flow rate changes with coarser precision, and is less affected in detection accuracy by viscosity changes in the fluid. On the basis of the temperature of the fluid detected by the temperature sensor, the control part switches between pump control based on the detection results of the flow sensor and pump control based on the detection results of the flow switch.

A high-efficiency air conditioning system for conditioning a plurality of rooms within an interior of a building, the air conditioning system including: two separate rooms within a building, a single outdoor unit a refrigerant flow pathway that includes a plurality of refrigerant conduits having a common refrigerant flow path portion and at least two divergent flow path portions, a first divergent flow path where the first evaporator and second evaporator are in parallel with one another; at least one throttling device and at least a first indoor air handling unit positioned within and providing cooling to the first room and a second indoor air handling unit positioned within and providing cooling to a second room. The compressor is incapable of simultaneously supplying both the first evaporator and the second evaporator at their full cooling capacity.

Provided is a temperature-adjusting fluid supply apparatus that causes a fluid for temperature adjustment to be circulated between a heat exchanger that transfers heat supplied from a refrigerant to the fluid, and an object to be adjusted for temperature that uses the heat of the fluid, the temperature-adjusting fluid supply apparatus being able to prevent the fluid from freezing. A temperature-adjusting fluid supply apparatus is provided with a heat exchanger that transfers heat supplied from a refrigerant to a fluid for temperature adjustment, a supply tube through which the fluid flows from the heat exchanger toward an object to be adjusted for temperature, a return tube through which the fluid returning from the object to be adjusted for temperature flows, a flow rate adjustable pump, a flow sensor, a flow switch, a temperature sensor, and a control part. The flow switch, in comparison with the flow sensor, is able to detect flow rate changes with coarser precision, and is less affected in detection accuracy by viscosity changes in the fluid. On the basis of the temperature of the fluid detected by the temperature sensor, the control part switches between pump control based on the detection results of the flow sensor and pump control based on the detection results of the flow switch.

A high-efficiency air conditioning system for conditioning a plurality of zones within an interior of a building that includes: at least two independent ductwork systems within a building wherein each independent ductwork system directs heating and cooling to one zone within the building; a single outdoor unit a refrigerant flow pathway having a common refrigerant flow path portion, a first divergent flow path, and a second divergent flow path; at least one throttling device and at least a first indoor air handling unit providing cooling to a first independent ductwork system and a second indoor air handling unit providing cooling to a second indoor ductwork system. The compressor is incapable of simultaneously supplying both the first evaporator and the second evaporator at their full cooling capacity.

A method of maintaining a fluid flow rate in a heating, ventilating, air conditioning, and refrigeration (HVAC-R) system while maintaining superheat in the HVAC-R system at a desired level includes: continuously measuring an operating fluid temperature of the HVAC-R system, continuously calculating HVAC-R system superheat at a pre-determined rate, determining if the calculated HVAC-R system superheat is stable, measuring and recording the operating fluid pressure of the HVAC-R system each time the calculated HVAC-R system superheat is stable, recording an average operating fluid pressure each subsequent time the superheat is stable, calculating an output PWM according to the equation: Output PWM=(Flow Rate Component)+(Superheat Component), and reducing fluid flow through a metering valve in the HVAC-R system when an actual HVAC-R system PWM is greater than the calculated output HVAC-R system PWM by adjusting a PWM signal to a microvalve in the metering valve, and increasing fluid flow through the metering valve in the HVAC-R system when the actual HVAC-R system PWM is less than the calculated output HVAC-R system PWM by adjusting the PWM signal to the microvalve in the metering valve.

A multi-circuit heat pump is disclosed. The heat pump comprises an evaporator, a plurality of condensers fluidically connected in series, and a plurality of compressor units configured between the evaporator and the plurality of condensers such that one of the compressor units is fluidically configured between the evaporator and one of the condensers.