A recent trend in heat pump systems is that gas injection systems are becoming more common. In this type of system, additional refrigerant at an intermediate pressure is injected into the compressor. This injected refrigerant is obtained by expanding part of the liquid leaving the condenser and vaporizing it with a heat source, such as the condenser liquid line. This vapor injection increases the possible operation range, the COP and the capacity.
This injection mass flow and state are additional parameters which influence the performance of the compressor. In real systems, either a flash tank or an internal heat exchanger is used to generate the injected vapor. To analyse the compressor performance independently from other components, it must be possible to vary the injection flow rate independently from the injection state. This cannot be done on real systems. Instead, a dedicated setup is required. In a previous thesis a test-rig was designed and constructed.
In this work, the setup neefds to be further commsioned and additional data needs to be collected in function of rotational speed, suction and discharge conditions, as well as injection conditions. Finally a model should be developped that allows predicting the performance of a gas injection compressor, based on the measured data.
This thesis is in collaboration with Daikin Europe NV.