Iso-pentane and other high boiling point compounds are often added to refrigerants to increase their enthalpy of vaporisation and thus cooling power. New mixed refrigerants with an iso-pentane (i-C5) content between (5 and 20) mol% are under investigation by HD KSOE. One challenge with the use of these refrigerants is the potential for the iso-pentane to freeze when the refrigerant is cooled below the pure iso-pentane triple point (Tt = 112.6 K). The temperature at which solid iso-pentane can form will depend on the i-C5 content in the mixture; in general, mixtures with a lower i-C5 mol fraction will form a solid phase at lower temperatures. Increasing the i-C5 content will thus improve the refrigerant’s performance but this can come at the cost of an increased risk of solid formation.
As a result, it is necessary to quantify the dependence between the i-C5 solid melting temperature and composition. To address this knowledge gap, this project will investigate the solid melting temperature for two mixtures with iso-pentane compositions of (10 and 20) mol% with a high-pressure, cryogenic visual apparatus at UWA. This will involve using a HD video camera to acquire optical images of solid iso-pentane forming and melting in the mixtures of interest. This will allow HD KSOE to conduct a more holistic assessment of the performance of i-C5 containing refrigerants. The research was completed on time and on budget, allowing Heavy Development – Korea Shipbuilding & Offshore Engineering to conduct pilot tests of their new refrigerant cycle.
Partners: Hyundai Development – Korea Shipbuilding & Offshore Engineering, The University of Western Australia
Project Researcher: Prof. Eric May
Duration: 2 Months