The present disclosure provides methods and systems for regulating the room temperature in a room or in a plurality of rooms, the room temperature can be regulated by regulating the mass flow of a heat-carrying fluid flowing through a heat exchanger according to a determined current room temperature. In accordance with some embodiments, a temperature sensor in the room can be dispensed that can determine the current room temperature, in each case the mass flow of the heat carrying fluid through the heat exchanger and the flow temperature prevailing at the input to the heat exchanger and the return temperature prevailing at the output of the heat exchanger are measured, and that a temperature assigned to the determined values of the mass flow, the flow temperature and the return temperature is output as the current room temperature and used for regulation.

A split air conditioning system for conditioning a plurality of zones within a single living area of a building, that includes a single outdoor unit; a refrigerant flow pathway made up of 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 and a second divergent flow path and the first evaporator and second evaporator are in parallel with one another; at least one throttling device; a portioning device configured to selectively and proportionately regulate the flow of a refrigerant fluid to the first evaporator and the second evaporator, respectively where the compressor is configured to be capable of simultaneously driving both the first evaporator and the second evaporator at their full cooling capacity.

A flow rate of a heat transfer medium is computed without a flow meter. In a control apparatus (30), a storing portion (36) stores an aerodynamic characteristic map indicating a line causing a rotating stall and lines showing a sonic velocity in a refrigerant sucked in by a compressor (12) on a map displaying a variable reflecting a suction volume of the compressor (12) and a variable reflecting a head of the compressor (12); a estimation portion of chilled water flow rate (30b) computes the variable , derives the variable according to the variable from the map, computes a heat amount exchanged between the refrigerant and the chilled water in an evaporator (24) based on the suction volume of the compressor (12) according to the computed variable , and computes the flow rate of the chilled water based on the heat amount.