Development of empirical correlations for non-adiabatic capillary tube based on mechanistic model

Capillary tubes play a vital role in the refrigeration cycle, as they reduce the temperature of the refrigerant. The non-adiabatic capillary tube (capillary tube-suction line heat exchanger: CT-SLHX) is widely incorporated into small refrigeration systems to enhance the cooling performance and ensure that only the refrigerant vapor enters the compressor. It is necessary to develop an accurate and fast-running non-adiabatic capillary tube model, as the performance of the refrigeration cycle simulation tool is largely dependent on the accuracy and run-time its component models. In the present study, a reliable mechanistic model was used to generate reference data. An empirical model was developed based on the data produced by this mechanistic model. This new empirical model was validated against experimental measurements available in the literature for R-134a and R-600a. The new model is fast-running and its performance metrics are in good agreement with experimentally measured data.

► Suction Line Heat exchangers enhance performance of refrigeration systems.
► Empirical correlation of SLHX was developed.
► Reference data were generated by a mechanistic model.
► New model outperforms the current ASHRAE model.