Thermodynamic Assessment of Using Water as a Refrigerant in Cascade Refrigeration Systems with other Environmentally Friendly Refrigerants

2021 ◽  
pp. 1-33
Author(s):  
Yousif Alkhulaifi ◽  
Esmail M. A. Mokheimer
Keyword(s):  
Low Temperature ◽  
Thermodynamic Assessment ◽  
Environmentally Friendly ◽  
Volumetric Flow Rate ◽  
Operational Parameters ◽  
Discharge Temperature ◽  
Refrigerant Alternatives ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration ◽  
Top Cycle

Abstract For current and future sustainability, refrigerants with high global warming potential (GWP) are being phased out and replaced with environmentally friendly refrigerants. To this end, research into the current and possible future low-GWP refrigerant alternatives in cascade refrigeration systems caught much attention. In this paper, a mathematical model is developed to assess the optimum energetic, exergetic, and operational parameters of a cascade refrigeration system using water as a refrigerant in the upper cycle with R744, N2O, R41, R717, R290, and R1270 in the lower cycle for a cooling load of 10 TR (35.2 kW). Multiple studies have been conducted for evaporator temperatures between -25 and 5 °C. Results show that R41 and R717 as low- and intermediate-temperature refrigerants, respectively, are recommended for the bottom cycle. Furthermore, R717-water showed improved COP compared to other top cycle refrigerants, with a COP improvement of 2.9% to 8.6%. This study demonstrates the thermal feasibility of using water as a refrigerant in low-temperature cascade systems. Using water as a refrigerant in the top cycle showed good results in low-temperature applications without the risk of solidification. However, the drawbacks are the high volumetric flow rate and compressor discharge temperature, requiring a large capacity water injected compressor.

A novel low-temperature absorption–compression cascade refrigeration system

2015 ◽  
Vol 75 ◽  
pp. 504-512 ◽  
Author(s):  
Yingjie Xu ◽  
FuSheng Chen ◽  
Qin Wang ◽  
Xiaohong Han ◽  
Dahong Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Refrigeration System ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration

Energy and Exergy Analysis of Cascade Refrigeration System Using MC22 and MC134 on HTC, R404A and R502 on LTC

2021 ◽  
Vol 80 (1) ◽  
pp. 73-83
Author(s):  
Hendri ◽  
Roswati Nurhasanah ◽  
Prayudi ◽  
Suhengki
Keyword(s):  
Low Temperature ◽  
Exergy Analysis ◽  
Refrigeration System ◽  
Low Temperature Storage ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration ◽  
Better Than ◽  
Temperature Storage

Low temperature storage with a single refrigeration system only stable up to 228 K temperature. The purpose of this study is to develop a low temperature cool storage with cascade refrigeration system, with hydrocarbon refrigerants in terms of energy and exergy analysis. Experimental research in laboratories using refrigerant hydrocarbon MC22 and MC134 on the hight temperature circuit, and R404A and R502 using on low temperature circuit. Condenser heat exchanger using a type of exchanger plate. Resulting from this research, obtained that result the MC22/R404A, MC22/R502 and MC134/R404A refrigerant pair can reach a temperature of 220 K. The MC22/R404A refrigerant pair has god performance, COP, total loss exergy, and exergy efficiency is better than MC22/R502, and MC134/R04A refrigerant pairs.

SIMULATION OF A LOW TEMPERATURE EVAPORATOR IN A CASCADE REFRIGERATION SYSTEM

2011 ◽  
Vol 19 (03) ◽  
pp. 203-212 ◽  
Author(s):  
DUSHYANTHA GUNAWARDANE ◽  
PRADEEP BANSAL
Keyword(s):  
Low Temperature ◽  
Cross Flow ◽  
Finned Tube ◽  
Temperature Cycle ◽  
Refrigeration System ◽  
Mass Flow Rates ◽  
Cascade Refrigeration System ◽  
Refrigeration Capacity ◽  
Cascade Refrigeration ◽  
System Operating

This paper presents a mathematical model for the evaporator of a cascade refrigeration system, operating down to -40°C. The system uses Carbon dioxide (R744) and Propylene (R1270), respectively, as the low temperature and high temperature cycle refrigerant. The model is developed in Engineering Equation Solver software package following the elemental Number of Transfer Units-effectiveness method, where frost has not been considered. The evaporator is a cross-flow finned tube serpentine heat exchanger, which was divided into numerous elements along the flow path of the refrigerant. The inputs to the model include inlet temperatures and mass flow rates of both the streams along with the heat flux, while the main outputs are the outlet temperatures, refrigeration capacity and HX effectiveness. The model is found to underpredict the refrigeration capacity by about 10% when compared with experimental data.

Energy and exergy analysis of a subcritical cascade refrigeration system with internal heat exchangers using environmentally-friendly refrigerants

2020 ◽  
pp. 1-33
Author(s):  
Cenker Aktemur ◽  
Ilhan Tekin Öztürk
Keyword(s):  
Heat Exchangers ◽  
Internal Heat ◽  
Exergy Efficiency ◽  
Refrigeration System ◽  
Evaporator Temperature ◽  
Discharge Temperature ◽  
Thermodynamic Performance ◽  
Condenser Temperature ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration

Abstract This study focuses on a thermodynamic performance analysis of a subcritical cascade refrigeration system (CRS) with internal heat exchangers (IHXs) using R41/R601, R41/R602A, and R41/cyclopentane as refrigerant pairs. The effect of evaporator temperature (Tev), condenser temperature (Tcond) and temperature difference in cascade heat exchanger (ΔTCHX) on examined performance parameters are investigated. Each performance parameter is scrutinized by an optimum LTC condenser temperature. The operating parameters have some implications on the overall thermodynamic performance of the system. A change of 10°C in the Tev and Tcond affects the performance of the system by approximately +26% and −8%, respectively. Moreover, a variation of 1°C in the ΔTCHX reduces the performance of the system by about 2%. The effect of IHXs on the system has some interesting results. The COP and exergy efficiency values of the system using R41/cyclopentane tend to constantly decrease by nearly 4.05%. Although not as much as R41/cyclopentane, there is also a slight drop in the performance of other refrigerant pairs. The discharge temperature in LTC and HTC compressors exceeds 120°C for low-temperature refrigeration requirements, which is highly undesirable. Furthermore, the top priority components for the system improvement are HTC condenser, HTC compressor, and CHX. The refrigerant pairs with the thermodynamic performance from best to worst are R41/R601, R41/cyclopentane, and R41/R602A, respectively. Finally, the COP and exergy efficiency values of the modeled system are 10.40% higher and 3.06% lower, respectively, compared to current models in the literature.

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