Mass flow characteristics and empirical modeling of R22 and R410A flowing through electronic expansion valves Chasik Park, Honghyun Cho, Yongtaek Lee, Yongchan Kim * Department of Mechanical Engineering, Korea University, Anam-Dong, Sungbuk-Gu, Seoul 136-701, Republic of Korea Received 1 February 2007; received in revised form 28 March 2007; accepted 28 March 2007 Available online 14 April 2007 Abstract The applications of electronic expansion valves (EEVs) into multi-type heat pumps and inverter heat pumps in building air-conditioning systems have increased for comfort environmental control and energy conservation. However, test data and mass flow models of EEVs are very limited in open literature. The objectives of this study are to investigate the mass flow char- acteristics of R22 and R410A through EEVs and to develop an empirical correlation for the prediction of mass flow rates of R22 and R410A through EEVs. Mass flow rates through six EEVs were measured by varying the EEV opening, inlet and outlet pres- sures, and the subcooling. Mass flow rates of R410A were compared with those of R22 at the same test conditions. Based on the experimental data, an empirical correlation for mass flow predictions in EEVs was developed by modifying the orifice equation. The predictions of the present correlation showed good agreement with the measured data with average and standard deviations of 0.76% and 5.9%, respectively. Approximately 92% of the measured data were within 10% of the predictions. Ó 2007 Elsevier Ltd and IIR. All rights reserved. Keywords: Refrigeration; Air conditioning; Heat pump; Modelling; Flow; Flow rate; R22; R410A; Orifice; Electronic expansion valve Caracte ´ristiques du de ´bit massique et mode ´lisation empirique de R22 et de R410A en e ´coulement dans les de ´tendeurs e ´lectroniques Mots cle ´s : Re ´frige ´ration ; Conditionnement d’air ; Pompe a ` chaleur ; Mode ´lisation ; E ´ coulement ; De ´bit ; R22 ; R410A ; Orifice ; De ´tendeur e ´lectronique 1. Introduction The expansion device controls the refrigerant mass flow and balances the system pressure in a refrigeration cycle. A capillary tube, a short tube orifice, and a thermostatic ex- pansion valve (TXV) have been used as an expansion device * Corresponding author. Tel.: þ82 2 3290 3366; fax: þ82 2 921 5439. E-mail address: yongckim@korea.ac.kr (Y. Kim). 0140-7007/$35.00 Ó 2007 Elsevier Ltd and IIR. All rights reserved. doi:10.1016/j.ijrefrig.2007.03.011 Available online at www.sciencedirect.com International Journal of Refrigeration 30 (2007) 1401e1407 www.elsevier.com/locate/ijrefrig