Capillary tube expansion devices are used extensively in small refrigeration and unitary air conditioning systems. R1234yf is likely to replace R134a in the next few years in many small refrigeration systems worldwide because of the new environmental regulations being proposed. In this paper, we compare the length and diameter of capillary tube required when R134a and R1234yf are used in a typical small refrigeration system. The minimum diameter of the capillary tube required has been estimated using the speed of sound of the refrigerant leaving the capillary tube in the two-phase state. The two-phase speed of sound routine developed by us can be used with both pure fluids and mixtures.

References

1.
Kim
,
S. G.
,
Kim
,
M. S.
, and
Ro
,
S. T.
,
2002
, “
Experimental Investigation of the Performance of R22, R407C and R410A in Several Capillary Tubes for Air-Conditioners
,”
Int. J. Refrig.
,
25
(
5
), pp.
521
531
.
2.
Bolstad
,
M. M.
, and
Jordan
,
R. C.
,
1948
, “
Theory and Use of the Capillary Tube Expansion Device
,”
Refrig. Eng.
,
56
(
12
), pp.
519
523
.
3.
Mikol
,
E. P.
, and
Dudley
,
J. C.
,
1964
, “
A Visual and Photographic Study of the Inception of Vaporization in Adiabatic Flow
,”
ASME Basic Eng.
,
86
(
2
), pp.
257
261
.
4.
Melo
,
C.
,
1992
, “
Modeling Adiabatic Capillary Tubes: A Critical Analysis
,”
International Refrigeration and Air Conditioning Conference
, pp.
113
123
.
5.
Bansal
,
P. K.
, and
Rupasinghe
,
A. S.
,
1998
, “
An Homogeneous Model for Adiabatic Capillary Tubes
,”
Appl. Therm. Eng.
,
18
(
97
), pp.
207
219
.
6.
Bansal
,
P. K.
, and
Wang
,
G.
,
2004
, “
Numerical Analysis of Choked Refrigerant Flow in Adiabatic Capillary Tubes
,”
Appl. Therm. Eng.
,
24
(
5–6
), pp.
851
863
.
7.
Zareh
,
M.
,
Shokouhmand
,
H.
,
Salimpour
,
M. R.
, and
Taeibi
,
M.
,
2014
, “
Numerical Simulation and Experimental Analysis of Refrigerants Flow Through Adiabatic Helical Capillary Tube
,”
Int. J. Refrig.
,
38
, pp.
299
309
.
8.
Melo
,
C.
,
Ferreira
,
R. T. S.
,
Neto
,
C. B.
,
Goncalves
,
J. M.
, and
Mezavila
,
M. M.
,
1999
, “
An Experimental Analysis of Adiabatic Capillary Tubes
,”
Appl. Therm. Eng.
,
19
(
6
), pp.
669
684
.
9.
Jung
,
D.
,
Park
,
C.
, and
Park
,
B.
,
1999
, “
Capillary Tube Selection for HCFC22 Alternatives
,”
Int. J. Refrig.
,
22
(
8
), pp.
604
614
.
10.
ASHRAE
,
2001
,
ASHRAE Handbook: Refrigeration
, Vol.
45
,
American Society of Heating, Refrigerating and Air Conditioning Engineers
,
Atlanta, GA
, pp.
25
30
.
11.
Shokouhmand
,
H.
, and
Zareh
,
M.
,
2014
, “
Experimental Investigation and Numerical Simulation of Choked Refrigerant Flow Through Helical Adiabatic Capillary Tube
,”
Appl. Therm. Eng.
,
63
(
1
), pp.
119
128
.
12.
Dirik
,
E.
,
Inan
,
C.
, and
Tanes
,
M. Y.
,
1994
, “
Numerical and Experimental Studies on Adiabatic and Nonadiabatic Capillary Tubes With HFC-134a
,”
International Refrigeration and Air Conditioning Conference
, pp.
365
370
.
13.
Lemmon
,
E. W.
,
Huber
,
M. L.
, and
McLinden
,
M. O.
,
2013
,
Reference Fluid Thermodynamic and Transport Properties—REFPROP
, Version 9.1,
NIST Standard Reference Database 23, National Institute of Standards and Technology
,
Gaithersburg, MD
.
14.
European Union
,
2014
, “
Regulation of the European Parliament and of the Council on Fluorinated Greenhouse Gases and Repealing Regulation
,” Regulation No. 517/2014.
15.
Karber
,
K. M.
,
Abdelaziz
,
O.
, and
Vineyard
,
E. A.
,
2012
, “
Experimental Performance of R-1234yf as a Drop-In Replacement for R-134a in Domestic Refrigerators
,”
International Refrigeration and Air Conditioning Conference
, pp.
1
9
.
16.
Chang
,
S.-D.
, and
Ro
,
S. T.
,
1996
, “
Pressure Drop of Pure HFC Refrigerants and Their Mixtures Flowing in Capillary Tubes
,”
Int. J. Multiphase Flow
,
22
(
3
), pp.
551
561
.
17.
Mikol
,
E. P.
,
1963
, “
Adiabatic Single and Two-Phase Flow in Small Bore Tubes
,”
ASHRAE J.
,
5
(
11
), pp.
75
86
.
18.
Kaleem
,
M.
,
Kumar
,
R.
, and
Sahoo
,
P. K.
,
2009
, “
Flow Characteristics of Refrigerants Flowing Through Capillary Tubes—A Review
,”
Appl. Therm. Eng.
,
29
(
8–9
), pp.
1426
1439
.
19.
Castier
,
M.
,
2011
, “
Thermodynamic Speed of Sound in Multiphase Systems
,”
Fluid Phase Equilib.
,
306
(
2
), pp.
204
211
.
20.
Lemmon
,
E. W.
, and
Tillner-Roth
,
R.
,
1999
, “
A Helmholtz Energy Equation of State for Calculating the Thermodynamic Properties of Fluid Mixtures
,”
Fluid Phase Equilib.
,
165
(
1
), pp.
1
21
.
21.
Karplus
,
H. B.
,
1957
, “
Velocity of Sound in a Liquid Containing Gas Bubbles
,”
J. Acoust. Soc. Am.
,
29
(
11
), pp.
1261
1262
.
22.
Park
,
C.
,
Lee
,
S.
,
Kang
,
H.
, and
Kim
,
Y.
,
2007
, “
Experimentation and Modeling of Refrigerant Flow Through Coiled Capillary Tubes
,”
Int. J. Refrig.
,
30
(
7
), pp.
1168
1175
.
You do not currently have access to this content.