HAL Id: hal-00618978 https://hal.archives-ouvertes.fr/hal-00618978 Submitted on 5 Sep 2011 HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Experimental study of an ammonia-water bubble absorber using a plate heat exchanger for absorption refrigeration machines Jesús Cerezo, Mahmoud Bourouis, Manel Vallès, Alberto Coronas, Roberto Best To cite this version: Jesús Cerezo, Mahmoud Bourouis, Manel Vallès, Alberto Coronas, Roberto Best. Experi- mental study of an ammonia-water bubble absorber using a plate heat exchanger for absorp- tion refrigeration machines. Applied Thermal Engineering, Elsevier, 2010, 29 (5-6), pp.1005. 10.1016/j.applthermaleng.2008.05.012. hal-00618978
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HAL Id: hal-00618978https://hal.archives-ouvertes.fr/hal-00618978
Submitted on 5 Sep 2011
HAL is a multi-disciplinary open accessarchive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come fromteaching and research institutions in France orabroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, estdestinée au dépôt et à la diffusion de documentsscientifiques de niveau recherche, publiés ou non,émanant des établissements d’enseignement et derecherche français ou étrangers, des laboratoirespublics ou privés.
Experimental study of an ammonia-water bubbleabsorber using a plate heat exchanger for absorption
refrigeration machinesJesús Cerezo, Mahmoud Bourouis, Manel Vallès, Alberto Coronas, Roberto
Best
To cite this version:Jesús Cerezo, Mahmoud Bourouis, Manel Vallès, Alberto Coronas, Roberto Best. Experi-mental study of an ammonia-water bubble absorber using a plate heat exchanger for absorp-tion refrigeration machines. Applied Thermal Engineering, Elsevier, 2010, 29 (5-6), pp.1005.�10.1016/j.applthermaleng.2008.05.012�. �hal-00618978�
[12] Cerezo J., Estudio del proceso de absorción con amoníaco-agua en
intercambiadores de placas para equipos de refrigeración por absorción, Ph. D. Thesis,
Rovira i Virgili University of Tarragona, Spain, 2006.
[13] Kakaç S., Liu H., heat exchangers: selection, rating, and thermal design. Boca
Raton, Florida,CRC, c1998.
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CAPTION LEGENDS Fig. 1. Schematic diagram of the experimental set-up.
Fig. 2. Injection of vapor in the absorber. Fig. 3. Effect of flow rate on the Nusselt number for cooling water at transition and turbulence zone. Fig. 4. Effect of solution Reynolds number and concentration on the solution heat transfer coefficient. Fig. 5. Effect of solution Reynolds number and concentration on the mass absorption flux. Fig. 6. Effect of solution Reynolds number on the absorber thermal load. Fig. 7. Effect of cooling water temperature on the (a) absorber thermal load and (b) heat transfer coefficient. Fig. 8. Effect of the absorber pressure on (a) the solution heat transfer coefficient, and (b) mass absorption flux. Fig. 9. Effect of the inlet solution concentration on (a) the solution heat transfer coefficient, (b) and mass absorption flux. Fig. 10. Effect of cooling water flow rate on (a) the solution heat transfer coefficient, and (b) mass absorption flux. Fig. 11. Effect of the cooling flow rate on (a) the overall mass transfer coefficient, and (b) degree of subcooling of the solution leaving the absorber.
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Fig. 1. Schematic diagram of the experimental set-up.
Flowmeter
C
T
P Pressure
Temperature
Coriolis Flowmeter
F
T
T
F F
C TS
ABS HX1
Cooling water circuit
Heating water circuit
P
TA
SVL
BA
T
P
Water
T T
Test section
C HX2
HX3
Solution circuit
P
HX4
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Ammonia vapor
Poor solution
Rich solution
Fig. 2. Injection of vapor in the absorber.
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0
20
40
60
80
0 200 400 600 800 1000ReC
Nu C
TransitionTurbulent
Fig. 3. Effect of flow rate on the Nusselt number for cooling water at transition and turbulence zone.
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2
3
4
5
6
7
120 170 220 270 320 370ReS
h S, k
W/m
2 K
PA=1.6 Bar, TS = 38°C, TC = 38°C, mC = 140kg/h
xIN = 29% wtxIN = 33% wt
3.8
5.0
Fig. 4. Effect of solution Reynolds number and concentration on the solution heat transfer coefficient.
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2
4
6
8
10
120 170 220 270 320 370
ReS
F AB, k
g/m
2 s (x
10-3
)
xIN=29%wtxIN=33%wt
PA=1.6 Bar, TS = 38°C, TC = 38°C, mC = 140 kg/h
Fig. 5. Effect of solution Reynolds number and concentration on the mass absorption flux.
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0.3
0.7
1.1
1.5
1.9
120 170 220 270 320 370ReS
QA
B, k
W
xIN=29%wtxIN=33%wt
PA=1.6 Bar, TS = 38°C, TC = 38°C, mC = 140kg/h
Fig. 6. Effect of solution Reynolds number on the absorber thermal load.
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0.0
0.4
0.8
1.2
1.6
2.0
2.4
100 200 300 400 500ReS
QA
B, k
W
TC = 30°CTC = 35°C
PAB=2 Bar, xIN=33.4%wt, TSOL=42°C, mC=140 kg/h
(a)
2
3
4
5
6
7
8
9
10
100 200 300 400 500ReS
h S, k
W/m
2 K
PAB=2 Bar, xIN=33.4%wt, TSOL=42°C, mC=140 kg/h
TC = 30°CTC = 35°C
(b)
Fig. 7. Effect of cooling water temperature on the (a) absorber thermal load and (b) heat transfer coefficient.
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2345678
910
120 170 220 270 320 370 420
ReS
h S, k
W/m
2 KxIN=33.4%wt, TC=30°C,TS=38°C, mC=140 kg/h
PAB = 2.0 BarPAB = 1.6 Bar
(a)
0
2
4
6
8
10
120 170 220 270 320 370 420ReS
F AB, k
g/m
2 s (x
10-3
)
PAB = 2.0 BarPAB = 1.6 Bar
xIN=33.4%wt, TC=30°C, TS=38°C, mC=140 kg/h
(b)
Fig. 8. Effect of the absorber pressure on (a) the solution heat transfer coefficient, and (b) mass absorption flux.
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2
3
4
5
6
7
8
9
10
100 200 300 400 500ReS
h S, k
W/m
2 K TS=38°CTS=42°C
PA=2 Bar, xIN=33.4%wt, TC=30°C,mC=140 kg/h
(a)
2
3
4
5
6
7
8
9
10
100 150 200 250 300 350 400 450ReS
F AB,
kg/m
2 s (x
10-3
)
TS=38°CTS=42°C
PA=2 Bar, xIN=33.4%wt, TC=30°C, mC=140 kg/h
(b)
Fig. 9. Effect of the inlet solution concentration on (a) the solution heat transfer coefficient, (b) and mass absorption flux.
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2
3
4
5
6
7
8
9
10
250 300 350 400 450 500 550 600ReC
h S, k
W/m
2 KPAB=2 Bar, xIN=33.4%wt, TS=38°C, TC=30°C
mS= 30 kg/hmS= 40 kg/h
(a)
0
2
4
6
8
10
250 300 350 400 450 500 550 600ReC
F AB, k
g/m
2 s
PAB=2 Bar, xIN=33.4%wt, TS=38°C, TC=30°C
mS=30 kg/hmS=40 kg/h
(b)
Fig. 10. Effect of cooling water flow rate on (a) the solution heat transfer coefficient, and (b) mass absorption flux.
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0.0000
0.0010
0.0020
0.0030
0.0040
200 300 400 500 600 700ReC
Km
, m/s
PAB=2 Bar, xIN = 33.4% wt, TS=42°C, mC=140 kg/h
mS = 50 kg/h
(a)
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
200 300 400 500 600 700ReC
Deg
ree
of su
bcoo
ling,
K
FSOL = 50 kg/h
PAB=2 Bar, xIN = 33.4% wt, TS=42°C, mC=140 kg/h
(b)
Fig. 11. Effect of the cooling flow rate on (a) the overall mass transfer coefficient, and (b) degree of subcooling of the solution leaving the absorber.
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Table 1 Measured variable and accuracy of the instruments
Name Instrumentation Variable measured Accuracy C Coriolis flowmeter Density
Solution flow rate ± 0.2, kg m-3 ± 0.05% of flow rate
F Cooling flowmeter Water flow rate ± 0.25% of flow rate
P Pressure Gauge Pressure ± 0.02, bar T PT100 Temperature ± 0.1, K
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Table 2 Absorber operating conditions
Parameter Range
Outlet solution temperature (°C) 30 - 40 Vapor temperature (°C) -8 - 0 Inlet solution temperature (°C) 35 - 55 Inlet solution concentration (NH3 mass fraction) 0.30 - 0.38 Outlet solution concentration (NH3 mass fraction) 0.31 - 0.42