Energy and Exergy Analysis of the Air Source Transcritical CO 2 Heat Pump Water Heater Using CO 2 -Based Mixture as Working Fluid

Yikai Wang, Yifan He, Yulong Song, Xiang Yin, Feng Cao and Xiaolin Wang
Additional contact information
Yikai Wang: School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Yifan He: School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Yulong Song: School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Xiang Yin: School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Feng Cao: School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Xiaolin Wang: School of Engineering, University of Tasmania, Hobart, TAS 7001, Australia

Energies, 2021, vol. 14, issue 15, 1-18

Abstract: Given the large demand nowadays for domestic hot water, and its impact on modern building energy consumption, air source transcritical CO 2 heat pumps have been extensively adopted for hot water production. Since their system efficiency is limited by significant irreversibility, a CO 2 -based mixture could offer a promising drop-in technology to overcome this deficiency without increasing system complexity. Although many CO 2 blends have been studied in previously published literature, little has been presented about the CO 2 /R32 mixture. Therefore, a proposed mixture for use in transcritical CO 2 heat pumps was analyzed using energy and exergy analysis. Results showed that the coefficient of performance and exergy efficiency variation displayed an “M” shape trend, and the optimal CO 2 /R32 mixture concentration was determined as 0.9/0.1 with regard to flammability and efficiency. The irreversibility of the throttling valve was reduced from 0.031 to 0.009 kW⋅kW −1 and the total irreversibility reduction was more notable with ambient temperature variation. A case study was also conducted to examine domestic hot water demand during the year. Pure CO 2 and the proposed CO 2 blend were compared with regard to annual performance factor and annual exergy efficiency, and the findings could provide guidance for practical applications in the future.

Keywords: transcritical CO 2 heat pump; energy analysis; exergy analysis; CO 2 -based mixture; ambient temperature; case study (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/1996-1073/14/15/4470/pdf (application/pdf)
https://www.mdpi.com/1996-1073/14/15/4470/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:14:y:2021:i:15:p:4470-:d:600490

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().