Abstract
Simple equipment for measuring the coefficient of performance (COP) requires a basic thermodynamics approach and many coefficients of the gas state equation and saturated liquid line equation are affected by factors such as pressure, temperature, and volume. The coefficients used in these equations vary depending on the literature. In this study, the influence of a change in the coefficients on the precision of the COP calculation was examined. The enthalpy was calculated at seven points on the heat pump cycle, which were all reproduced adequately, with low errors, compared to the reference values. The errors of the calculated enthalpies increased when the coefficients deviated from their original values. The coefficients were changed by 14 different values between − 10 % and 10 %. However, the observed enthalpy differences between two points with similar states for either wet vapor or superheated vapor were consistent with the reference values for low values, because the same equations were used for Hou–Martin or saturated liquid lines, respectively. The absolute mean error of the COP exceeded 1.0 when the coefficients were increased by 2 %, and 0.793 at the maximum value when the coefficient decreased negatively. This worse precision could mean that different enthalpy equations were used in the process of the COP calculation, whose states were a mixture of wet and superheated vapor.
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Abbreviations
- Cp id :
-
Temperature-dependent specific heat at constant pressure (J·kg−1·K−1)
- df :
-
Density of saturated liquid (kg·m−3)
- H :
-
Specific enthalpy (kJ·kg−1)
- P :
-
Pressure (kPa)
- Psat :
-
Pressure of saturated vapor (kPa)
- r :
-
Vaporization of heat (kJ·kg−1)
- S :
-
Specific entropy (J·kg−1·K−1)
- T :
-
Temperature K
- Tc :
-
Temperature at critical point (K)
- Tcon :
-
Temperature of condenser (K)
- Teva :
-
Temperature of evaporator (K)
- Tr :
-
Temperature ratio: T/Tc (dimensionless)
- Tsc :
-
Degree of supercooling (K)
- Tsh :
-
Degree of superheating functions defined by Eq. 5 for saturated (K)
- Xh, Xp :
-
Liquid line and Eq. 13 for saturated vapor pressure respectively (dimensionless)
- V :
-
Specific volume (m3·kg−1)
- V′, V″ :
-
Specific volumes of saturated liquid and saturated vapor respectively (m3·kg−1)
- \(\begin{array}{*{20}c} 1 & {1^{\prime}} & 2 & {2^{\prime}} \\ 3 & {3^{\prime}} & 4 & {4{\text{f}}} \\ \end{array}\) :
-
Thermodynamics state points-Fig. 1
- pg:
-
Pressure of refrigerant gas
- df:
-
Density of refrigerant fluid
- COP:
-
Coefficient of per
References
X. Yu, Y. Zhang, N. Deng, J. Wang, D. Zhang, J. Wang, Energy Build. 66, 657 (2013)
L. Alberti, M. Antelmi, A. Angelotti, G. Formentin, Agric. Water Manag. 195, 187 (2018)
L. Aresti, P. Christodoulides, G. Florides, Renew. Sustain. Energ. Rev. 92, 757 (2018)
K.D. Rafferty, Trans-Am. Soc. Heat. Refrig. Air Cond. Eng. 104, 927 (1998)
H. Fujii, R. Itoi, J. Fujii, Y. Uchida, Geotherm. 34, 347 (2005)
S. Lousso, G. Taddia, V. Verda, Geotherm. 43, 66 (2012)
P. Fleuchaus, P. Blum, Geotherm. Energ. (2017). https://doi.org/10.1186/s40517-017-0067-y
B. Sanner, E. Mands, M.K. Sauer, E. Grundmann, Proc. IEA HPC, 04–35. 20–22 May 2008, Zürich, Switzerland, 1–12
E.P. Gyftopoulos, G.P. Beretta (2005) Courier Corporation
S. Moritani, K. Sasaki, K. Itaka, Environ. Dev. Sustain. (2020). https://doi.org/10.1007/s10668-019-00518-x
NIST, REFPROP 10.0 software, National Institute of Standards and Technology, 2018, https://trc.nist.gov/refprop/REFPROP.PDF, Accessed 31 July 2019
JSRAE, Software of refrigerating cycle, Japan Society of Refrigerating and Air Conditioning Engineers, 2006, CD-ROM
A. Mota-Babiloni, J. Navarro-Esbrí, P. Makhnatch, F. Molés, Renew. Sustain. Energ. Rev. 80, 1031 (2017)
F. De Monte, Int. J. Refrig 25, 765 (2002)
A. Stegou-Sagia, A. Papadaki, V. Ioakim, Forsch. Ingenieurwes. 70, 253 (2005)
R. Roy, B.K. Mandal, Eng. Sci. Int. Res. J. 2, 163 (2014)
R. Djeffal, Z. Triki, M.K. Cherier, Proc. ACRA2014 May 18-21, 2014, Jeju, Korea
H. Atalay, M.T. Coban, Univ. J. Mech. Eng. 3, 229 (2015). https://doi.org/10.13189/ujme.2015.030604
R. Span, W. Wagner, J. Phys. Chem. Ref. Data 25, 1509 (1996). https://doi.org/10.1063/1.555991
F. de Monte, Int. J. Refrig 25, 314 (2002)
Thermodynamic Properties of Suva 410A Refrigerant. (DuPont™ Suva, E. I. du Pont de Nemours and company), https://resource.carrierenterprise.com/is/content/Watscocom/dupont-suva_d11920101_article_1442219482567_en_ss. Accessed 9 March 2020
E.P. Gyftopoulos, G.P. Beretta, Thermodynamics: Foundations and applications (Macmillan Publishing Company, New York, 1991)
J.J. Martin, Y.C. Hou, AIChE J. 1, 142 (1955)
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This work was funded by JSPS KAKENHI Grant Number 18K05895.
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Moritani, S., Akahira, A. Influence of Parameters on the Estimation of Coefficient of Performance for R410a Refrigerant. Int J Thermophys 41, 121 (2020). https://doi.org/10.1007/s10765-020-02699-4
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DOI: https://doi.org/10.1007/s10765-020-02699-4