MODELLING AND OPTIMIZATION OF COEFFICIENT OF PERFORMANCE OF LOWER TEMPERATURE CYCLE OF TWO-STEP REFRIGERATION SYSTEMS

  • A. D. Ogunsola Department of Mechanical Engineering, Ladoke Akintola University of Technology, P.M.B.4000, Ogbomoso, Oyo State. Nigeria
  • M. Y. Kolawole Department of Mechanical Engineering, Kwara State University, Malete, Kwara State
  • A. A. Aderibigbe Department of Mechanical Engineering, Ladoke Akintola University of Technology, P.M.B.4000, Ogbomoso, Oyo State. Nigeria
  • O. Olaogun Department of Mechanical Engineering, Kwara State University, Malete, Kwara State
  • A. J. Adeyi Department of Mechanical Engineering, Ladoke Akintola University of Technology, P.M.B.4000, Ogbomoso, Oyo State. Nigeria
  • O. Adeyi Department of Chemical Engineering, Michael Okpara University of Agriculture, P.M.B 7267, Umudike, Abia State, Nigeria.
  • M. O. Ibiwoye Department of Mechanical Engineering, Kwara State University, Malete, Kwara State
  • M. O. Adetunji Department of Mechanical Engineering, Ladoke Akintola University of Technology, P.M.B.4000, Ogbomoso, Oyo State. Nigeria
Keywords: COP, Sub-cooling, Superheating, Refrigeration, Cascade, Refrigerant

Abstract

The coefficient of performance (COP) of a single-stage refrigeration system is low, thus there is a need for two-step refrigeration systems when there is a desire to have an evaporator temperature that is below -25 oC. The COP of the lower temperature cycle of the two-step refrigeration systems is a function of the COP of the refrigeration systems.This research aimed at optimizing COP of the lower temperature cycle of two-step refrigeration systems using eco-friendly refrigerants.Thermodynamic analysis of these refrigeration systems was performed by varying seven operating parameters. R-134a was used in the high-temperature cycle (HTC) and R-23 was used in the low-temperature cycle (LTC). The coefficient of performance of the lower temperature cycle (COP.REF[LTC]) of the refrigeration systems was optimized using Half Factorial Design of Design-Expert 12.0.1. The influence of the condensing temperature (TC,HTC),evaporating temperature (TE,HTC), cascade temperature difference (∆TCAS,DIFF), evaporating temperature (TE,LTC), superheating temperature (TSUP,LTC), sub-cooling temperature (TSUB,LTC), and refrigerant mass Flow rate (ṁHTC)was investigated on the values of COP.REF[LTC] of the refrigeration systems. The highest value of COP.REF[LTC] (18.1) was obtained under optimum conditions of the 30 TC,HTCoC , -40 TE,HTCoC, 0 ∆TCAS,DIFFoC, -50 TE,LTCoC, 0 TSUP,LTCoC, 20 TSUB,LTCoC and 0.01 ṁHTC kg/s.The study revealed that all the factors having interaction with TC[HTC] and TE[HTC] have a great influence on the value of COP.REF[LTC]

Published
2022-06-28
How to Cite
Ogunsola, A., Kolawole, M., Aderibigbe, A., Olaogun, O., Adeyi, A., Adeyi, O., Ibiwoye, M., & Adetunji, M. (2022). MODELLING AND OPTIMIZATION OF COEFFICIENT OF PERFORMANCE OF LOWER TEMPERATURE CYCLE OF TWO-STEP REFRIGERATION SYSTEMS. LAUTECH Journal of Engineering and Technology, 16(2), 31-52. Retrieved from http://laujet.com/index.php/laujet/article/view/503