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Angel Barragancervera - One of the best experts on this subject based on the ideXlab platform.
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drop in analysis of an Internal Heat Exchanger in a vapour compression system using r1234ze e and r450a as alternatives for r134a
Energy, 2015Co-Authors: Adrian Motababiloni, Joaquin Navarroesbri, Francisco Moles, Angel Barragancervera, Bernardo PerisAbstract:The IHX (Internal Heat Exchanger) is introduced in some refrigeration systems in order to achieve higher energy performances. Results obtained vary greatly depending on the refrigerant used and working conditions. This paper describes a drop-in analysis of IHX effects on the performance of a vapour compression system using R1234ze(E) and R450A (R134a/R1234ze(E) commercial mixture) as R134a low-GWP replacements. The tests were carried out in a completely monitored vapour compression system varying the condensing and evaporating temperature, with and without a counter-current flow tube-in-tube IHX. Because the cooling capacity rises and the power consumption remains similar, the conclusion is that the IHX has a positive influence on the energy efficiency for all refrigerants tested. The COP (coefficient of performance) gain using R1234ze(E) is the highest observed (overcomes the R134a COP for the same conditions). The R1234ze(E) and R450A discharge temperature increments are lower than those of R134a so does not reach dangerous values and the IHX pressure drops are also below than that of R134a.
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theoretical energy performance evaluation of different single stage vapour compression refrigeration configurations using r1234yf and r1234ze e as working fluids
International Journal of Refrigeration-revue Internationale Du Froid, 2014Co-Authors: Francisco Moles, Joaquin Navarroesbri, Adrian Motababiloni, Bernardo Peris, Angel BarragancerveraAbstract:R1234yf and R1234ze(E) have been proposed as alternatives for R134a in order to work with low GWP refrigerants, but this replacement results generally in a decrease of the performance. For this reason, it is interesting to explore ways to improve the system performance using these refrigerants. In this paper, a comparative study in terms of energy performance of different single stage vapour compression configurations using R1234yf and R1234ze(E) as working fluids has been carried out. The most efficient configuration is the one which uses an expander or an ejector as expansion device. On the other hand, using an Internal Heat Exchanger in a cycle which replaces the expansion valve by an expander or an ejector could produce a detrimental effect on the COP. However, for all the configurations the introduction of an Internal Heat Exchanger produces a significant increment on the cooling capacity.
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experimental analysis of the Internal Heat Exchanger influence on a vapour compression system performance working with r1234yf as a drop in replacement for r134a
Applied Thermal Engineering, 2013Co-Authors: Joaquin Navarroesbri, Francisco Moles, Angel BarragancerveraAbstract:This paper presents an experimental analysis of the influence of an Internal Heat Exchanger on the performance of a vapour compression system using R1234yf as a drop-in replacement for R134a. In this work, we compare the energy performance of a monitored vapour compression system using both refrigerants, R134a and R1234yf, with and without the presence of an Internal Heat Exchanger under a wide range of working conditions. A set of experimental tests are carried out varying the condensing temperature, the evaporating temperature and the Internal Heat Exchanger use. From the experimental results, reductions in cooling capacity and COP between 6 and 13% have been observed when R134a is replaced by the drop-in fluid R1234yf, although the presence of an IHX can help to lessen these reductions between 2 and 6%. Finally, the experimental results obtained agree with the theoretical evaluations developed neglecting the pressure drops.
E Torrella - One of the best experts on this subject based on the ideXlab platform.
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experimental evaluation of an Internal Heat Exchanger in a co2 subcritical refrigeration cycle with gas cooler
Applied Thermal Engineering, 2015Co-Authors: R Llopis, Carlos Sanzkock, R Cabello, D Sanchez, E TorrellaAbstract:Abstract We present the experimental evaluation of an Internal Heat Exchanger or suction-line/liquid-line Heat Exchanger in a CO2 subcritical refrigeration plant with gas-cooler. The plant, driven by a 1.5 kW CO2 semi hermetic compressor, uses brazed plate Heat Exchangers as condenser, evaporator and Internal Heat Exchanger, an air finned tube gas-cooler and an electronic expansion valves. The evaluation (77 steady-states) covers evaporating temperatures from −40 to −25 °C and condensing temperatures from −15 to 0 °C, always at the nominal speed of the compressor. Here, the effect of the Internal Heat Exchanger on the main energy parameters is analysed, i.e., cooling capacity, COP and Heat rejection at gas-cooler and condenser. Also, the effect of the Internal Heat Exchanger in a cascade cycle is analysed theoretically. It has been concluded that the Internal Heat Exchanger does not improve the performance of the subcritical cycle, but it could improve the energy performance if it is used inside a cascade refrigeration system.
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new positions for an Internal Heat Exchanger in a co2 supercritical refrigeration plant experimental analysis and energetic evaluation
Applied Thermal Engineering, 2014Co-Authors: D Sanchez, R Llopis, R Cabello, E Torrella, J Patino, Fernando Vicente FuentesAbstract:IHX is probably, one of the most commonly alternative used to improve cooling capacity and COP in a CO2 refrigerating plant working in supercritical conditions. The “classical” position at gas-cooler exit has been analyzed by several authors with positive results. The aim of this work is to compare, from experimental approach, the energetic behavior of a refrigerating plant working with several IHX configurations: gas-cooler exit (classical position), liquid receiver exit, and in both positions at the same time. The energetic behavior includes: cooling capacity, power consumption and COP. Moreover, the discharge temperature reached on each position has been analyzed. From the experimental results, a general improvement in COP and cooling capacity has been observed regardless the position of the IHX. A maximum increment of 13% on COP has been registered working with two IHX at the same time.
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energetic evaluation of an Internal Heat Exchanger in a co2 transcritical refrigeration plant using experimental data
International Journal of Refrigeration-revue Internationale Du Froid, 2011Co-Authors: E Torrella, R Llopis, D Sanchez, R CabelloAbstract:Abstract The performance of an Internal Heat Exchanger (IHX) operating in a CO 2 transcritical refrigeration plant is analysed, from an energetic point of view, in this work. The evaluation is based on experimental data by contrasting the performance of the plant working with (44 tests) and without the IHX (46 tests) at the same operating conditions. The experimental evaluation covers three evaporating levels (−5, −10 and −15 °C), at two different gas-cooler outlet temperatures each (31, 34 °C), for a wide range of gas-cooler operating pressures (74.5–105.9 bar). The thermal effectiveness of the IHX is empirically analysed for the different operating conditions in the first part of the paper. Moreover, the relation of its effectiveness with the operating parameters is presented. The second part is devoted to analyse the modification of the energetic performance of the plant caused by the IHX. The results show a maximum increment on cooling capacity of 12%, an increment of the efficiency of the plant up to 12% and a maximum increase on discharge temperature of 10 °C at −15 °C of evaporating temperature.
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experimental evaluation of the Internal Heat Exchanger influence on a vapour compression plant energy efficiency working with r22 r134a and r407c
Energy, 2005Co-Authors: Joaquin Navarroesbri, R Cabello, E TorrellaAbstract:Internal or liquid-suction Heat Exchangers are used in many refrigeration and air conditioning systems based on the vapour compression cycle, with the basic objective of assuring the entrance of refrigerant in liquid phase to the expansion device. This purpose is achieved by exchanging energy between the cool gaseous refrigerant leaving the evaporator and warm liquid refrigerant exiting the condenser. These devices can have positive or negative influences on the plant overall energy efficiency, depending on the working fluid and the operating conditions. In this paper the experimental results obtained from a refrigeration test facility with and without the presence of an Internal Heat Exchanger, using R22, R134a and R407C as working fluids, are presented and analyzed, including the impact of pressure drops and variations of refrigerant mass flow rate. A comparison between experimental and theoretical results is also enclosed.
R Cabello - One of the best experts on this subject based on the ideXlab platform.
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effects caused by the Internal Heat Exchanger at the low temperature cycle in a cascade refrigeration plant
Applied Thermal Engineering, 2016Co-Authors: R Llopis, Carlos Sanzkock, R Cabello, D Sanchez, Laura Nebotandres, Jesus CatalangilAbstract:Abstract This work analyses and quantifies the effects caused by the use of an Internal Heat Exchanger (IHX) at the CO 2 subcritical cycle in an HFC134a/CO 2 cascade refrigeration plant that incorporates a gas-cooler at the exit of the low temperature compressor. Previous theoretical and experimental studies showed that the IHX reduces the refrigeration capacity and COP of the subcritical cycle, however, it has been seen that it also lowers the Heat to be rejected at the condenser. This reduction, when the cycle is a part of a cascade system, allows reducing the Heat load of the high temperature cycle, modifying the working conditions of the cascade plant. The modifications result in an increment of the overall coefficient of performance of the cascade system. The analysis here presented is based on the evaluation of an experimental HFC134a/CO 2 refrigeration plant, which has been analysed with and without Internal Heat Exchanger in an evaporating temperature range from −40 to −30 °C and in a condensing one from 30 to 50 °C. The plant incorporates a gas-cooler at the exit of the CO 2 compressor. The experimental results confirm that the IHX slightly reduces the cooling capacity but it can increment the overall COP up to 3.7%.
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experimental evaluation of an Internal Heat Exchanger in a co2 subcritical refrigeration cycle with gas cooler
Applied Thermal Engineering, 2015Co-Authors: R Llopis, Carlos Sanzkock, R Cabello, D Sanchez, E TorrellaAbstract:Abstract We present the experimental evaluation of an Internal Heat Exchanger or suction-line/liquid-line Heat Exchanger in a CO2 subcritical refrigeration plant with gas-cooler. The plant, driven by a 1.5 kW CO2 semi hermetic compressor, uses brazed plate Heat Exchangers as condenser, evaporator and Internal Heat Exchanger, an air finned tube gas-cooler and an electronic expansion valves. The evaluation (77 steady-states) covers evaporating temperatures from −40 to −25 °C and condensing temperatures from −15 to 0 °C, always at the nominal speed of the compressor. Here, the effect of the Internal Heat Exchanger on the main energy parameters is analysed, i.e., cooling capacity, COP and Heat rejection at gas-cooler and condenser. Also, the effect of the Internal Heat Exchanger in a cascade cycle is analysed theoretically. It has been concluded that the Internal Heat Exchanger does not improve the performance of the subcritical cycle, but it could improve the energy performance if it is used inside a cascade refrigeration system.
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new positions for an Internal Heat Exchanger in a co2 supercritical refrigeration plant experimental analysis and energetic evaluation
Applied Thermal Engineering, 2014Co-Authors: D Sanchez, R Llopis, R Cabello, E Torrella, J Patino, Fernando Vicente FuentesAbstract:IHX is probably, one of the most commonly alternative used to improve cooling capacity and COP in a CO2 refrigerating plant working in supercritical conditions. The “classical” position at gas-cooler exit has been analyzed by several authors with positive results. The aim of this work is to compare, from experimental approach, the energetic behavior of a refrigerating plant working with several IHX configurations: gas-cooler exit (classical position), liquid receiver exit, and in both positions at the same time. The energetic behavior includes: cooling capacity, power consumption and COP. Moreover, the discharge temperature reached on each position has been analyzed. From the experimental results, a general improvement in COP and cooling capacity has been observed regardless the position of the IHX. A maximum increment of 13% on COP has been registered working with two IHX at the same time.
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energetic evaluation of an Internal Heat Exchanger in a co2 transcritical refrigeration plant using experimental data
International Journal of Refrigeration-revue Internationale Du Froid, 2011Co-Authors: E Torrella, R Llopis, D Sanchez, R CabelloAbstract:Abstract The performance of an Internal Heat Exchanger (IHX) operating in a CO 2 transcritical refrigeration plant is analysed, from an energetic point of view, in this work. The evaluation is based on experimental data by contrasting the performance of the plant working with (44 tests) and without the IHX (46 tests) at the same operating conditions. The experimental evaluation covers three evaporating levels (−5, −10 and −15 °C), at two different gas-cooler outlet temperatures each (31, 34 °C), for a wide range of gas-cooler operating pressures (74.5–105.9 bar). The thermal effectiveness of the IHX is empirically analysed for the different operating conditions in the first part of the paper. Moreover, the relation of its effectiveness with the operating parameters is presented. The second part is devoted to analyse the modification of the energetic performance of the plant caused by the IHX. The results show a maximum increment on cooling capacity of 12%, an increment of the efficiency of the plant up to 12% and a maximum increase on discharge temperature of 10 °C at −15 °C of evaporating temperature.
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experimental evaluation of the Internal Heat Exchanger influence on a vapour compression plant energy efficiency working with r22 r134a and r407c
Energy, 2005Co-Authors: Joaquin Navarroesbri, R Cabello, E TorrellaAbstract:Internal or liquid-suction Heat Exchangers are used in many refrigeration and air conditioning systems based on the vapour compression cycle, with the basic objective of assuring the entrance of refrigerant in liquid phase to the expansion device. This purpose is achieved by exchanging energy between the cool gaseous refrigerant leaving the evaporator and warm liquid refrigerant exiting the condenser. These devices can have positive or negative influences on the plant overall energy efficiency, depending on the working fluid and the operating conditions. In this paper the experimental results obtained from a refrigeration test facility with and without the presence of an Internal Heat Exchanger, using R22, R134a and R407C as working fluids, are presented and analyzed, including the impact of pressure drops and variations of refrigerant mass flow rate. A comparison between experimental and theoretical results is also enclosed.
R Llopis - One of the best experts on this subject based on the ideXlab platform.
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effects caused by the Internal Heat Exchanger at the low temperature cycle in a cascade refrigeration plant
Applied Thermal Engineering, 2016Co-Authors: R Llopis, Carlos Sanzkock, R Cabello, D Sanchez, Laura Nebotandres, Jesus CatalangilAbstract:Abstract This work analyses and quantifies the effects caused by the use of an Internal Heat Exchanger (IHX) at the CO 2 subcritical cycle in an HFC134a/CO 2 cascade refrigeration plant that incorporates a gas-cooler at the exit of the low temperature compressor. Previous theoretical and experimental studies showed that the IHX reduces the refrigeration capacity and COP of the subcritical cycle, however, it has been seen that it also lowers the Heat to be rejected at the condenser. This reduction, when the cycle is a part of a cascade system, allows reducing the Heat load of the high temperature cycle, modifying the working conditions of the cascade plant. The modifications result in an increment of the overall coefficient of performance of the cascade system. The analysis here presented is based on the evaluation of an experimental HFC134a/CO 2 refrigeration plant, which has been analysed with and without Internal Heat Exchanger in an evaporating temperature range from −40 to −30 °C and in a condensing one from 30 to 50 °C. The plant incorporates a gas-cooler at the exit of the CO 2 compressor. The experimental results confirm that the IHX slightly reduces the cooling capacity but it can increment the overall COP up to 3.7%.
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experimental evaluation of an Internal Heat Exchanger in a co2 subcritical refrigeration cycle with gas cooler
Applied Thermal Engineering, 2015Co-Authors: R Llopis, Carlos Sanzkock, R Cabello, D Sanchez, E TorrellaAbstract:Abstract We present the experimental evaluation of an Internal Heat Exchanger or suction-line/liquid-line Heat Exchanger in a CO2 subcritical refrigeration plant with gas-cooler. The plant, driven by a 1.5 kW CO2 semi hermetic compressor, uses brazed plate Heat Exchangers as condenser, evaporator and Internal Heat Exchanger, an air finned tube gas-cooler and an electronic expansion valves. The evaluation (77 steady-states) covers evaporating temperatures from −40 to −25 °C and condensing temperatures from −15 to 0 °C, always at the nominal speed of the compressor. Here, the effect of the Internal Heat Exchanger on the main energy parameters is analysed, i.e., cooling capacity, COP and Heat rejection at gas-cooler and condenser. Also, the effect of the Internal Heat Exchanger in a cascade cycle is analysed theoretically. It has been concluded that the Internal Heat Exchanger does not improve the performance of the subcritical cycle, but it could improve the energy performance if it is used inside a cascade refrigeration system.
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new positions for an Internal Heat Exchanger in a co2 supercritical refrigeration plant experimental analysis and energetic evaluation
Applied Thermal Engineering, 2014Co-Authors: D Sanchez, R Llopis, R Cabello, E Torrella, J Patino, Fernando Vicente FuentesAbstract:IHX is probably, one of the most commonly alternative used to improve cooling capacity and COP in a CO2 refrigerating plant working in supercritical conditions. The “classical” position at gas-cooler exit has been analyzed by several authors with positive results. The aim of this work is to compare, from experimental approach, the energetic behavior of a refrigerating plant working with several IHX configurations: gas-cooler exit (classical position), liquid receiver exit, and in both positions at the same time. The energetic behavior includes: cooling capacity, power consumption and COP. Moreover, the discharge temperature reached on each position has been analyzed. From the experimental results, a general improvement in COP and cooling capacity has been observed regardless the position of the IHX. A maximum increment of 13% on COP has been registered working with two IHX at the same time.
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energetic evaluation of an Internal Heat Exchanger in a co2 transcritical refrigeration plant using experimental data
International Journal of Refrigeration-revue Internationale Du Froid, 2011Co-Authors: E Torrella, R Llopis, D Sanchez, R CabelloAbstract:Abstract The performance of an Internal Heat Exchanger (IHX) operating in a CO 2 transcritical refrigeration plant is analysed, from an energetic point of view, in this work. The evaluation is based on experimental data by contrasting the performance of the plant working with (44 tests) and without the IHX (46 tests) at the same operating conditions. The experimental evaluation covers three evaporating levels (−5, −10 and −15 °C), at two different gas-cooler outlet temperatures each (31, 34 °C), for a wide range of gas-cooler operating pressures (74.5–105.9 bar). The thermal effectiveness of the IHX is empirically analysed for the different operating conditions in the first part of the paper. Moreover, the relation of its effectiveness with the operating parameters is presented. The second part is devoted to analyse the modification of the energetic performance of the plant caused by the IHX. The results show a maximum increment on cooling capacity of 12%, an increment of the efficiency of the plant up to 12% and a maximum increase on discharge temperature of 10 °C at −15 °C of evaporating temperature.
Joaquin Navarroesbri - One of the best experts on this subject based on the ideXlab platform.
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drop in analysis of an Internal Heat Exchanger in a vapour compression system using r1234ze e and r450a as alternatives for r134a
Energy, 2015Co-Authors: Adrian Motababiloni, Joaquin Navarroesbri, Francisco Moles, Angel Barragancervera, Bernardo PerisAbstract:The IHX (Internal Heat Exchanger) is introduced in some refrigeration systems in order to achieve higher energy performances. Results obtained vary greatly depending on the refrigerant used and working conditions. This paper describes a drop-in analysis of IHX effects on the performance of a vapour compression system using R1234ze(E) and R450A (R134a/R1234ze(E) commercial mixture) as R134a low-GWP replacements. The tests were carried out in a completely monitored vapour compression system varying the condensing and evaporating temperature, with and without a counter-current flow tube-in-tube IHX. Because the cooling capacity rises and the power consumption remains similar, the conclusion is that the IHX has a positive influence on the energy efficiency for all refrigerants tested. The COP (coefficient of performance) gain using R1234ze(E) is the highest observed (overcomes the R134a COP for the same conditions). The R1234ze(E) and R450A discharge temperature increments are lower than those of R134a so does not reach dangerous values and the IHX pressure drops are also below than that of R134a.
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theoretical energy performance evaluation of different single stage vapour compression refrigeration configurations using r1234yf and r1234ze e as working fluids
International Journal of Refrigeration-revue Internationale Du Froid, 2014Co-Authors: Francisco Moles, Joaquin Navarroesbri, Adrian Motababiloni, Bernardo Peris, Angel BarragancerveraAbstract:R1234yf and R1234ze(E) have been proposed as alternatives for R134a in order to work with low GWP refrigerants, but this replacement results generally in a decrease of the performance. For this reason, it is interesting to explore ways to improve the system performance using these refrigerants. In this paper, a comparative study in terms of energy performance of different single stage vapour compression configurations using R1234yf and R1234ze(E) as working fluids has been carried out. The most efficient configuration is the one which uses an expander or an ejector as expansion device. On the other hand, using an Internal Heat Exchanger in a cycle which replaces the expansion valve by an expander or an ejector could produce a detrimental effect on the COP. However, for all the configurations the introduction of an Internal Heat Exchanger produces a significant increment on the cooling capacity.
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experimental analysis of the Internal Heat Exchanger influence on a vapour compression system performance working with r1234yf as a drop in replacement for r134a
Applied Thermal Engineering, 2013Co-Authors: Joaquin Navarroesbri, Francisco Moles, Angel BarragancerveraAbstract:This paper presents an experimental analysis of the influence of an Internal Heat Exchanger on the performance of a vapour compression system using R1234yf as a drop-in replacement for R134a. In this work, we compare the energy performance of a monitored vapour compression system using both refrigerants, R134a and R1234yf, with and without the presence of an Internal Heat Exchanger under a wide range of working conditions. A set of experimental tests are carried out varying the condensing temperature, the evaporating temperature and the Internal Heat Exchanger use. From the experimental results, reductions in cooling capacity and COP between 6 and 13% have been observed when R134a is replaced by the drop-in fluid R1234yf, although the presence of an IHX can help to lessen these reductions between 2 and 6%. Finally, the experimental results obtained agree with the theoretical evaluations developed neglecting the pressure drops.
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experimental evaluation of the Internal Heat Exchanger influence on a vapour compression plant energy efficiency working with r22 r134a and r407c
Energy, 2005Co-Authors: Joaquin Navarroesbri, R Cabello, E TorrellaAbstract:Internal or liquid-suction Heat Exchangers are used in many refrigeration and air conditioning systems based on the vapour compression cycle, with the basic objective of assuring the entrance of refrigerant in liquid phase to the expansion device. This purpose is achieved by exchanging energy between the cool gaseous refrigerant leaving the evaporator and warm liquid refrigerant exiting the condenser. These devices can have positive or negative influences on the plant overall energy efficiency, depending on the working fluid and the operating conditions. In this paper the experimental results obtained from a refrigeration test facility with and without the presence of an Internal Heat Exchanger, using R22, R134a and R407C as working fluids, are presented and analyzed, including the impact of pressure drops and variations of refrigerant mass flow rate. A comparison between experimental and theoretical results is also enclosed.