TY  - CONF
AU  - Černicin, Vladimir
AU  - Milovančević, Uroš
AU  - Otović, Milena
AU  - Zhang, Wenying
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6827
AB  - Theoretical cycle analysis is an indispensable part of the refrigeration system and heat pump (HP) design. However, due to the simplicity of the calculations and numerous assumptions, there is a deviation from the actual behavior of the system. In this paper, a single-stage, reversible CO2 system, which can operate in both air-conditioning and heating mode, with and without an internal heat exchanger (IHX), was presented. In the heating mode, the deviation of the theoretical cycle from the actual cycle of the heat pump was analyzed, under various operating conditions. Actual cycles were formed based on the experimental investigation of this system. The changes of various parameters and deviations that are made due to a simpler calculation are presented.
PB  - International Institute of Refrigeration
C3  - Proceedings of 10th Conference on Ammonia and CO2 Refrigeration Technology
T1  - THE DIFFERENCE BETWEEN SIMPLIFIED THEORETICAL AND EXPERIMENTAL CYCLE ANALYSIS OF CO2 HEAT PUMP
DO  - 10.18462/iir.nh3-co2.2023.0027
ER  - 

@conference{
author = "Černicin, Vladimir and Milovančević, Uroš and Otović, Milena and Zhang, Wenying",
year = "2023",
abstract = "Theoretical cycle analysis is an indispensable part of the refrigeration system and heat pump (HP) design. However, due to the simplicity of the calculations and numerous assumptions, there is a deviation from the actual behavior of the system. In this paper, a single-stage, reversible CO2 system, which can operate in both air-conditioning and heating mode, with and without an internal heat exchanger (IHX), was presented. In the heating mode, the deviation of the theoretical cycle from the actual cycle of the heat pump was analyzed, under various operating conditions. Actual cycles were formed based on the experimental investigation of this system. The changes of various parameters and deviations that are made due to a simpler calculation are presented.",
publisher = "International Institute of Refrigeration",
journal = "Proceedings of 10th Conference on Ammonia and CO2 Refrigeration Technology",
title = "THE DIFFERENCE BETWEEN SIMPLIFIED THEORETICAL AND EXPERIMENTAL CYCLE ANALYSIS OF CO2 HEAT PUMP",
doi = "10.18462/iir.nh3-co2.2023.0027"
}

Černicin, V., Milovančević, U., Otović, M.,& Zhang, W.. (2023). THE DIFFERENCE BETWEEN SIMPLIFIED THEORETICAL AND EXPERIMENTAL CYCLE ANALYSIS OF CO2 HEAT PUMP. in Proceedings of 10th Conference on Ammonia and CO2 Refrigeration Technology
International Institute of Refrigeration..
https://doi.org/10.18462/iir.nh3-co2.2023.0027

Černicin V, Milovančević U, Otović M, Zhang W. THE DIFFERENCE BETWEEN SIMPLIFIED THEORETICAL AND EXPERIMENTAL CYCLE ANALYSIS OF CO2 HEAT PUMP. in Proceedings of 10th Conference on Ammonia and CO2 Refrigeration Technology. 2023;.
doi:10.18462/iir.nh3-co2.2023.0027 .

Černicin, Vladimir, Milovančević, Uroš, Otović, Milena, Zhang, Wenying, "THE DIFFERENCE BETWEEN SIMPLIFIED THEORETICAL AND EXPERIMENTAL CYCLE ANALYSIS OF CO2 HEAT PUMP" in Proceedings of 10th Conference on Ammonia and CO2 Refrigeration Technology (2023),
https://doi.org/10.18462/iir.nh3-co2.2023.0027 . .

TY  - CONF
AU  - Černicin, Vladimir
AU  - Zhang, Wenying
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5734
AB  - The use of an internal heat exchanger (IHX) as a cycle improvement measure is very common with CO2 systems. However, a simple thermodynamic analysis is not able to fully indicate the advantages of IHX in a single-stage system. For this reason, in this paper, the effect of the internal heat exchanger on the reversible CO2 system, which can work in both air-conditioning and heating mode, was experimentally investigated. Experiments were performed under various conditions for both operating modes, with and without an internal heat exchanger. The results of the experiments showed that in the heating mode (heat pump) the coefficient of performance (COP) can be increased up to 10,5% by introducing the internal heat exchanger, while in the air-conditioning mode, the COP can be increased up to 13,8%. Also, it has been shown that this improvement provides safer system operation and less frost formation on the evaporator.
PB  - Beograd: SMEITS
C3  - Zbornik 53. Međunarodnog kongresa o KGH, 2022
T1  - THE EFFECT OF INTERNAL HEAT EXCHANGER IN A REVERSIBLE CO2 SYSTEM UNDER VARIOUS OPERATING CONDITIONS
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5734
ER  - 

@conference{
author = "Černicin, Vladimir and Zhang, Wenying",
year = "2023",
abstract = "The use of an internal heat exchanger (IHX) as a cycle improvement measure is very common with CO2 systems. However, a simple thermodynamic analysis is not able to fully indicate the advantages of IHX in a single-stage system. For this reason, in this paper, the effect of the internal heat exchanger on the reversible CO2 system, which can work in both air-conditioning and heating mode, was experimentally investigated. Experiments were performed under various conditions for both operating modes, with and without an internal heat exchanger. The results of the experiments showed that in the heating mode (heat pump) the coefficient of performance (COP) can be increased up to 10,5% by introducing the internal heat exchanger, while in the air-conditioning mode, the COP can be increased up to 13,8%. Also, it has been shown that this improvement provides safer system operation and less frost formation on the evaporator.",
publisher = "Beograd: SMEITS",
journal = "Zbornik 53. Međunarodnog kongresa o KGH, 2022",
title = "THE EFFECT OF INTERNAL HEAT EXCHANGER IN A REVERSIBLE CO2 SYSTEM UNDER VARIOUS OPERATING CONDITIONS",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5734"
}

Černicin, V.,& Zhang, W.. (2023). THE EFFECT OF INTERNAL HEAT EXCHANGER IN A REVERSIBLE CO2 SYSTEM UNDER VARIOUS OPERATING CONDITIONS. in Zbornik 53. Međunarodnog kongresa o KGH, 2022
Beograd: SMEITS..
https://hdl.handle.net/21.15107/rcub_machinery_5734

Černicin V, Zhang W. THE EFFECT OF INTERNAL HEAT EXCHANGER IN A REVERSIBLE CO2 SYSTEM UNDER VARIOUS OPERATING CONDITIONS. in Zbornik 53. Međunarodnog kongresa o KGH, 2022. 2023;.
https://hdl.handle.net/21.15107/rcub_machinery_5734 .

Černicin, Vladimir, Zhang, Wenying, "THE EFFECT OF INTERNAL HEAT EXCHANGER IN A REVERSIBLE CO2 SYSTEM UNDER VARIOUS OPERATING CONDITIONS" in Zbornik 53. Međunarodnog kongresa o KGH, 2022 (2023),
https://hdl.handle.net/21.15107/rcub_machinery_5734 .

TY  - CONF
AU  - Zhang, Wenying
AU  - Černicin, Vladimir
AU  - Hrnjak, Pega
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5733
AB  - This paper first presents a comprehensive review of the internal heat exchanger, followed by the discussion of experimental results of the role of an internal heat exchanger in an R744 air conditioning system. The effects of refrigerant charge amount on the performance of both basic and internal heat exchanger systems were investigated. Also, the control equations of COP-maximizing high-side pressure were developed and used for both systems. The experimental data show up to 13.8% improvement in efficiency by introducing the internal heat exchanger. The different roles of IHX in sub- and transcritical modes and the reason for the difference are discussed in the paper.
PB  - Purdue University, Ray W. Herrick Laboratories
C3  - Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue
T1  - THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE AIR-CONDITIONING MODE UNDER VARIOUS CONDITIONS
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5733
ER  - 

@conference{
author = "Zhang, Wenying and Černicin, Vladimir and Hrnjak, Pega",
year = "2022",
abstract = "This paper first presents a comprehensive review of the internal heat exchanger, followed by the discussion of experimental results of the role of an internal heat exchanger in an R744 air conditioning system. The effects of refrigerant charge amount on the performance of both basic and internal heat exchanger systems were investigated. Also, the control equations of COP-maximizing high-side pressure were developed and used for both systems. The experimental data show up to 13.8% improvement in efficiency by introducing the internal heat exchanger. The different roles of IHX in sub- and transcritical modes and the reason for the difference are discussed in the paper.",
publisher = "Purdue University, Ray W. Herrick Laboratories",
journal = "Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue",
title = "THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE AIR-CONDITIONING MODE UNDER VARIOUS CONDITIONS",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5733"
}

Zhang, W., Černicin, V.,& Hrnjak, P.. (2022). THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE AIR-CONDITIONING MODE UNDER VARIOUS CONDITIONS. in Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue
Purdue University, Ray W. Herrick Laboratories..
https://hdl.handle.net/21.15107/rcub_machinery_5733

Zhang W, Černicin V, Hrnjak P. THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE AIR-CONDITIONING MODE UNDER VARIOUS CONDITIONS. in Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_5733 .

Zhang, Wenying, Černicin, Vladimir, Hrnjak, Pega, "THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE AIR-CONDITIONING MODE UNDER VARIOUS CONDITIONS" in Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue (2022),
https://hdl.handle.net/21.15107/rcub_machinery_5733 .

TY  - CONF
AU  - Černicin, Vladimir
AU  - Zhang, Wenying
AU  - Hrnjak, Pega
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5665
AB  - In this paper, the role of the internal heat exchanger (IHX) in a reversible R744 vapor compression system in the heating mode was investigated experimentally and presented. At the first, the optimal refrigerant charge amount for both basic and the IHX systems was determined. Also, the control equations of HPF-maximizing high side pressure were developed and used for both systems. Then, well-tuned systems working at the optimal discharge pressure were compared in two scenarios under various conditions. The results of the experiments reveal the potential benefits of introducing IHX for the R744 system in the heating mode. The efficiency was improved by up to 10.5% by introducing the internal heat exchanger. Also, the benefits of IHX in the frosting conditions were discussed.
PB  - Purdue University, Ray W. Herrick Laboratories
C3  - Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue
T1  - THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE HEAT PUMP MODE UNDER VARIOUS CONDITIONS
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5665
ER  - 

@conference{
author = "Černicin, Vladimir and Zhang, Wenying and Hrnjak, Pega",
year = "2022",
abstract = "In this paper, the role of the internal heat exchanger (IHX) in a reversible R744 vapor compression system in the heating mode was investigated experimentally and presented. At the first, the optimal refrigerant charge amount for both basic and the IHX systems was determined. Also, the control equations of HPF-maximizing high side pressure were developed and used for both systems. Then, well-tuned systems working at the optimal discharge pressure were compared in two scenarios under various conditions. The results of the experiments reveal the potential benefits of introducing IHX for the R744 system in the heating mode. The efficiency was improved by up to 10.5% by introducing the internal heat exchanger. Also, the benefits of IHX in the frosting conditions were discussed.",
publisher = "Purdue University, Ray W. Herrick Laboratories",
journal = "Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue",
title = "THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE HEAT PUMP MODE UNDER VARIOUS CONDITIONS",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5665"
}

Černicin, V., Zhang, W.,& Hrnjak, P.. (2022). THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE HEAT PUMP MODE UNDER VARIOUS CONDITIONS. in Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue
Purdue University, Ray W. Herrick Laboratories..
https://hdl.handle.net/21.15107/rcub_machinery_5665

Černicin V, Zhang W, Hrnjak P. THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE HEAT PUMP MODE UNDER VARIOUS CONDITIONS. in Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_5665 .

Černicin, Vladimir, Zhang, Wenying, Hrnjak, Pega, "THE ROLE OF INTERNAL HEAT EXCHANGER IN AN R744 VAPOR COMPRESSION SYSTEM IN THE HEAT PUMP MODE UNDER VARIOUS CONDITIONS" in Proceedings of 19th International Refrigeration and Air Conditioning Conference at Purdue (2022),
https://hdl.handle.net/21.15107/rcub_machinery_5665 .