2008-2012 NTU-OSAR

This project was carried out in the period from 2008 to 2012 as a joint research and development at New Energy Center of the Mechanical Engineering Department, National Taiwan University, Taipei, Taiwan, in cooperation with the Odessa State Academy of Refrigeration, Ukraine, in the area of ejector refrigerating technologies that was based on the Global Research Partnership Award (GRP Award), granted by the King Abdullah University of Science and Technology (KAUST), Saudi Arabia.

The main objectives of the present research include:

  1. Determine the most suitable working fluid for the ejector refrigeration machine (ERM).
  2. Build an ejector test rig for the study of improved ejector construction and ejector flow profile design and performance evaluation.
  3. Design and develop an ERM with an optimal working fluid that will have high coefficients of performance (COPs).

Theoretical analysis of ejector design and ejector refrigeration cycle performance was carried out. Analysis showed that the performance characteristics of ejectors and the ejector refrigeration cycle depend strongly on the operating conditions, the efficiency of the ejector used, and the thermodynamic properties of the refrigerant used. Cmparative analysis of the performance characteristics of eight low-pressure refrigerants confirms that the environmentally friendly hydrocarbons butane (R600) and isobutane (R600a) and working fluid R245fa offer the best performance combinations and, at present, are the most suitable choices for application in ejector chillers and air conditioners. Refrigerant R245fa was selected as the most suitable working fluid for general purpose applications in the present study.

Figure 1. Photograph of the ejector test rig

Figure 1. Photograph of the ejector test rig

To verify the theoretical analysis of the ejector geometry and performance characteristics of the ERM using refrigerant R245fa, an ejector test rig with maximum a cooling capacity of 12kW was designed and constructed. A photograph of the ejector test rig are shown in Figure 1. The ejector test rig equipment includes the following major components: an experimental ejector, a generator, an evaporator, a condenser, a receiver-subcooler, a float regulating valve, a gear-type feed pump, a cooling tower and a control panel equipped with different measurement instrumentation. A PC-based monitoring and control system was developed in the present study for the ejector test rig. Pressures, temperatures, primary and secondary flow rates, electric power consumption and other required data were recorded and the results were calculated. This enabled the main performance to be determined in a steady state condition of system operation.

Figure 2. Photograph of the experimental ejector

Figure 2. Photograph of the experimental ejector

A photograph of the experimental ejector assembly with two retrofract symmetrical suction inlet ducts is shown in Figure 2. The assembly of the ejector consists of the following main components: a body, an axially movable supersonic nozzle, a mixing chamber made jointly with the diffuser, a frame and a mechanism to move the nozzle into optimal position with respect to the entrance of the mixing chamber.

In order to carry out experimental investigations in wide range of operating conditions three supersonic nozzles and three cylindrical mixing chambers were designed and manufactured. In order to compare the performance of ejectors for R245fa using cylindrical mixing chambers with ejectors using conical-cylindrical mixing chambers, three conical-cylindrical mixing chambers were designed and manufactured to carry out the experimental investigations at the same operating conditions.

Experimental investigations was carried out in wide range of operating conditions and ejector geometrical characteristics. The main results of a theoretical and experimental investigation of the performance characteristics of an ejector and an ejector refrigeration machine operating with refrigerant R245fa at design and off-design working conditions are presented in articles and abstracts on international conferences (see list below).

Outstanding Scholar Award

REFERENCES

  1. Huang B.J., Chen S.L., Petrenko V.O., Shestopalov K.O. Theoretical and experimental investigation of the performance characteristics of an ejector cooling machine operating with refrigerant R245fa // Book of abstracts, IIR International Congress of Refrigeration. – 21-26 August, 2011. – Prague, Czech Republic. – p. 69.
  2. Huang B.J., Petrenko V.O., Shestopalov K.O. Investigation of experimental ejector cooling machine operating with refrigerant R245fa designed for solar air conditioning application // The proceedings of the ISES Solar World Congress. – 28 August - 2 September, 2011. – Kassel, Germany.
  3. Petrenko V.O., Shestopalov K.O., Volovyk O.S., Huang B.J. Theoretical and experimental investigation of ejector refrigeration machine operating with refrigerant R245fa, Book of abstracts, part 1, p.35-37, The Seventh International Conference “Modern Problems of Refrigerating Engineering and Technology” September 14-16, 2011, Odessa, OSAR, Ukraine (in Russian).
  4. Petrenko V.O., Volovyk O.S., Shestopalov K.O., Huang B.J. Investigation of an ejector cooling machine operating with refrigerant R245fa at designed and off-design working conditions, Part I. J. Refrigeration Engineering and Technology, ¹2 (136), pp. 21-28, 2012 (in Russian).
  5. Petrenko V.O., Volovyk O. S., Shestopalov K.O., Huang B.J. Investigation of an ejector cooling machine operating with refrigerant R245fa at designed and off-design working conditions, Part II. J. Refrigeration Engineering and Technology, ¹3 (137), pp. 26-35, 2012 (in Russian).
  6. Petrenko V.O., Volovyk O.S., Shestopalov K.O., Huang B.J. Theoretical and experimental investigation of the methods increasing performance characteristics of ejector refrigeration machines, Book of Papers, p.104-110, The Eighth International Conference “Sustainable Development and Artificial Cold” October 8-10, 2012, Odessa, OSAR, Ukraine (in Russian).
  7. Volovyk O.S. Improvement of characteristics and performances of an ejector refrigeration machine operating with low-boiling working fluids. Odessa National Academy of Food Technologies, Ukraine. – Ph.D. thesis, 2013.
  8. Shestopalov K.O., Huang B.J., Petrenko V.O., Volovyk O.S. Investigation of an experimental ejector refrigeration machine operating with refrigerant R245fa at design and off-design working conditions. Part 1. Theoretical analysis, International Journal of Refrigeration. – 2015. – Vol. 55, – pp. 201-211.
  9. Shestopalov K.O., Huang B.J., Petrenko V.O., Volovyk O.S. Investigation of an experimental ejector refrigeration machine operating with refrigerant R245fa at design and off-design working conditions. Part 2. Theoretical and experimental results, International Journal of Refrigeration. – 2015. – Vol. 55, – pp. 212-223.