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An Experimental Study on Water Harvesting from a Modified Window Air-Conditioner
Available online at www.sciencedirect.com
ScienceDirect Energy Procedia 109 (2017) 253 – 260
International Conference on Recent Advancement in Air Conditioning and Refrigeration, RAAR 2016, 10-12 November 2016, Bhubaneswar, India
An Experimental Study on Water Harvesting from a Modified Window Air-Conditioner Purnendu Dalaia*, Prasant Nandab,Chinmaya Munda, Debasmita Mishrab, Abhijeet Guptac a
Department of Mechanical Engineering,CVRCE, Bhubaneswar, odisha,752054, India Department of mechanical engineering,VSSUT, Burla, sambalpur, odisha, 768018, India c Department of mechanical engineering, hi-tech institute of technology,bhubaneswar,odisha,752057, India b
Abstract
An experimental study of the performance of an air conditioning system, using the concept of humidification-dehumidification is presented and investigated. The technique (AWVP) relies on utilizing the moisture present in atmospheric air and to increase its content to certain extent. The water extracted through this technique is of good standard and can be used for drinking and other purposes. The test setup consists of four loops namely fresh water circuit, air circuit, refrigerant circuit and dirty water circuit. Certain operating parameters like volume flow rate of air, air inlet temperature after heating and relative humidity was varied and its effect on the performance of the system was studied and analyzed. © by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license © 2017 2017Published The Authors. Published by Elsevier Ltd. (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility ofthe organizing committee of RAAR 2016. Peer-review under responsibility of the organizing committee of RAAR 2016. Keywords:Humidification, Dehumidification, AWVP.
1. Introduction The present age is having a serious problem of rising temperature and there is also an adequate shortage of portable drinking water. Although we have enormous amount of water available in sea and oceans but it cannot be used when and where it is required. There are also lot of diseases which occurs due to drinking of bad quality water. This all can be avoided innear future by simply modifying and utilizing some of our existing technologies. The technique of Atmospheric Water Vapour Processing (AWVP) is very useful in hot and humid climate.Besides AWVP technique, the system also utilizes the vapour compression refrigeration system. The system setup consists of four loops, out of which one is closed one and other three are open loops.
1876-6102 © 2017 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of RAAR 2016. doi:10.1016/j.egypro.2017.03.058
254
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
Nomenclature T1 T2 T3 T4 T5 T6 T7 P V T W R1 R2
Dry Bulb Temperature (DBT) of atmospheric air. Wet Bulb Temperature (WBT) of atmospheric air. DBT of air after it is being heated by Heating Coil. WBT of air after it is being heated by Heating Coil. DBT of air after water spraying. WBT of air after water spraying. DBT of cooled air from A.C. Outlet. Power in Watts. Volume Flow rate in m3/s. time in minutes. Water collected in millilitre. Relative humidity of atmospheric air. Relative humidity of air after water spraying.
Nafey et al. [1, 2] analyzed the humidification and dehumidification desalination process mathematically with accompanied experiments under the effect of solar energy with different environmental and operating conditions. They concluded that the mathematical result was in good agreement with the experimental results. air flow rate, cooling water flow rate and total solar energy influenced the efficiency of the unit. They also concluded that the area of the solar water collector area affected the system’s productivity immensely. Amer et al. [3] mathematically and experimentally analyzed the humidification–dehumidification desalination system. They developed a system with water on an open cycle and air stream in closed cycle. They circulated the air with natural or forced circulation. They experimented with varying operating conditions using different packing materials. The heat and mass transfer coefficients were obtained experimentally and then fitted in forms of empirical correlations. They concluded that with increase in the mass flow rate, the productivity of the system increases. The temperature of the water at the condenser increases linearly with the water temperature at the humidifier inlet and decreased as the rate of flow of water decreased. A maximum productivity of 5.8 l/h has been obtained using wooden slate packing and with forced air circulation. Farsad and Behzadmehr [4] developed the balanced equation for the components .and did a thermodynamic analysis for a solar HDH desalination system. They calculated the amount of fresh water production with the developed equation and finished the sensitivity analysis with the main parameters was completed with the design of experimental method.Thus finding out the optimum condition of the desalination process.Parekh et al. [5] did a in depth technical review of solar desalination with multiple effect cycle and concluded that the solar desalination based on the humidification and dehumidification process presents the best method of solar desalination due to overall high efficiency. Younis et al. [6] theoretically designed a procedure to desalinate seawater in which they preheated brackish water using solar collectors and then brought them in contact with the inlet air in an evaporation column followed by a condensation stack for dehumidification. In the present work an attempt has been made to retrofit a window air conditioner to simultaneously generate cooling effect and drinking water from atmospheric air. Atmospheric air was initially humidified with low and poor quality water and good quality water was harvested from it, which is suitable enough for human consumption. * Corresponding author. Tel.: 9040200968 E-mail address:[email protected]
255
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
2. Experimental setup The experimental set up consists of four independent circuit named, fresh air circuit, dirty water circuit, refrigerant circuit and fresh water circuit. Out of these four loops, only the refrigerant loop was closed one, while other three are open loops. The block diagram of the experimental setup is given in Fig. 1.
5
1
2
15
16
13
10
3
4
6
7
8
9
14
12 11 Fig. 1. Experimental Setup of modified window air-conditioner Table 1: Various parts of experimental set up of modified window air conditioner with dimensions. S.NO 1 2 3, 4 5 6
7 8, 9
PART Window air Conditioner Duct Duct
SIZE,CAPACITY 1.5 tonne
S.NO 10
PART Blower
16*16 inch 16*10 inch
11 12
Humidification Point Duct
NA
13
Variac NA Fresh Water NA Collection Point Valve 2.5 inch
10*10 inch
14
Duct CS Pipe
10*2.5 inch 2.5inch, 300mm
15 16
Pressure Tapings Manometer Heating Coil Orifice Plate
SIZE,CAPACITY NA
NA to 1000 W 10 mm
256
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
3. Experimental Procedure x x
x
x x x
An old window AC was taken and necessary repair was done. Other parts are fabricated with care, keeping dimensions in mind. Then assembly of different parts were done as per the set up shown in Fig. 1. The blower was started initially and the valve was set full open so that volume flow rate becomes maximum. Then variac was switched on and was set at 60 volt, so that power supply becomes 240 W. It was left for few minutes, so that after few minutes steady conditions were obtained. Once steady conditions were obtained i.e. reading for temperature and volume flow rate of air were stabilized, window AC was started and test was conducted for a span of 20 minutes. The test was performed separately by spraying water once and separately by without spraying water. The temperatures were recorded at various collection points, where suitable arrangements were made for recording the temperature. The water generated from AC was collected at a point and was measured with the help of a measuring beaker. The same set of steps was performed for different volume flow rate of air and for different variac settings.
4. Results and Discussions The experiment was performed for test duration of 20 minutes, after the setup has achieved steady state. Several parameters like volume flow rate, power supply werevaried and readings were taken. The readings are presented in a tabular manner. Table 2: The different sets of data collected from conducting the experiment when power = 160W. P in watts
V in m3/s
160
0.00729
160
0.00623
160
0.00542
160
0.00729
160
0.00623
160
0.00542
Test Type Dry run Dry run Dry run Wet Run Wet Run Wet Run
Time in Sec
T1
T2
T3
T4
T5
T6
T7
20
33
26
42
29
32
24
10
Water Collected in ml 750
20
31
26
42
29
29
24
8
20
30
26
43
30
28
26
20
35
26
41
29
28
20
26
24
32
25
20
35
29
43
31
R1
R2
59
53
1025
68
67
10
1100
72
86
24
11
805
54
73
24
21
9
1270
84
75
30
28
11
1000
65
86
257
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
Table 3: The different sets of data collected from conducting the experiment when power = 200W. P in watts
V in m3/s
Test Type
200
0.00729
200
0.00623
200
0.00542
200
0.00729
200
0.00623
200
0.00542
Dry run Dry run Dry run Wet Run Wet Run Wet Run
Time in Sec
T1
T2
T3
T4
T5
T6
T7
20
32
25
44
29
29
23
10
Water Collected in ml 675
20
31
26
42
29
29
24
8
20
33
25
46
29
29
25
20
32
25
42
28
29
20
26
24
40
29
20
36
28
45
30
R1
R2
57
60
1025
68
66
10
1120
53
72
24
10
1050
57
66
24
22
10
1480
84
83
29
26
10
850
56
84
Table 4: The different sets of data collected from conducting the experiment when power = 240W. P in watts 240
V in m3/s 0.00729
240
0.00623
240
0.00542
240
0.00729
240
0.00623
240
0.00542
Test Type Dry run Dry run Dry run Wet Run Wet Run Wet Run
Time in Sec 20
T1
T2
T3
T4
T5
T6
T7
R1
R2
52
56
34.5
26
50
30
31
24
11
Water Collected in ml 625
20
29
24
45
29
28
25
8
1035
67
78
20
34
28
54
33
30
27
11
850
65
80
20
30
25
45
29
29
25
11
1250
66
72
20
28
24.5
42
29
25
23
11
1325
75
84
20
35
28
46
31
29
27
11
930
60
78
Analyzing the results following graphs were plotted and following conclusions were deduced. The graphs were plotted in Microsoft Excel.
258
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
Fig. 2. Effect of volume flow rate and power on fresh water collected, keeping Power= 160 W constant.
In the above Fig. 2, graph was plotted between volume flow rate and water collected, keeping power= 160 W constant. In dry run test, water collected was maximum for the volume flow rate=0.00542 m3/s, and least for the volume flow rate of 0.00729 m3/s. In the dry run, water collected rate increases as the volume flow rate decreases. While in wet run test, water collected rate first increases and then decreases sharply, and its maximum when the volume flow rate was 0.00623 m3/s. In the present case, as the volume flow rate increases, the effective heat transfer coefficient increases so a better cooling effect was achieved, and hence water production also increases. However, when volume flow rate was further increased, the residence time of air over the cooling coil decreases leading to a lower yield. In fact at higher volume flow rate, a slight decrease in relative humidity has been noticed.
Fig. 3. Effect of volume flow rate and power on fresh water collected, keeping Power= 200 W constant.
In the above Fig. 3 graph was plotted between volume flow rate and water collected, keeping power= 200 W constant. The graph follows the same trend as in previous graph, where power= 160 W, was kept constant. In dry run test, water collected was maximum for the volume flow rate=0.00542 m3/s, and least for the volume flow rate of 0.00729 m3/s. In the dry run, water collected rate increases as the volume flow rate decreases. While in wet run test, water collectedrate first increases and then decreases sharply, and its maximum when the volume flow rate was 0.00623 m3/s.
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
259
Fig. 4 Effect of volume flow rate and power on fresh water collected, keeping Power= 240 W constant. The trend of water collection remain as par with the case, when power was 160 W. However the yield at higher volume flow rate in case of 240 W and for wet run case was found to be comparatively higher as compared with the dry run test due to better moisture absorption and higher heat transfer rate at higher temperature. The dehumidification done by the evaporator coils of window air conditioner gives us good quality water in which turbidity of collected water has gone down. 5. Conclusion In this paper a window air conditioner was modified to enhance the cooling effect and produce processcum drinking water.It was found that the amount of water collected depended on volume flow rate, cooling coil capacity, humidity, heat transfer coefficient and time of residence of air inside the window air conditioner. The water collection in all cases washigh for wet run test as compared to dry run test. Also the yield increases at higher temperature, this was due to the fact that at higher temperature water absorption capacity and heat transfer rate increases.The average water collection rate was 0.3 ml/s. The turbidity of water collected was much less than that used for spraying. The turbidity of water that is used for spraying and humidification was very high. It is translucent. But the water that we were getting from dehumidification done by the window air conditioner is transparent. This clearly shows that turbidity of collected water which can be used for drinking has tremendously gone down.
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Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
6. References
[1] A.S. Nafey, H.E.S. Fath, S.O. El-Helaby, A.M. Soliman, Solar desalination using humidification dehumidification processes: Part I, A numerical investigation, Energy Conversion and Management 45 (2004) 1243–1261. [2] A.S. Nafey, H.E.S. Fath, S.O. El-Helaby, A. Soliman, Solar desalination using humidification– dehumidification processes. Part II. An experimental investigation, Energy Convers. Manag. 45 (2004) 1263–1277. [3] E.H. Amer, H. Kotb, G.H. Mostafa, A.R. El-Ghalban, Theoretical and experimental investigation of humidification and dehumidification desalination unit, Desalination 249 (2009) 949–959. [4] Farsad S, Behzadmehr A. Analysis of a solar desalination unit with humidification–dehumidification cycle using DoE method. Desalination 2011; 278:70–6. [5] S. Parekh, M.M. Farid, J.R. Selman and S. Al-Hallaj, Solar desalination with a humidification– dehumidification technique — a comprehensive technical review, Desalination, 160 (2004) 167–186. [6] M.A. Younis, M.A. Darwish and F. Juwayhel, Experimental and theoretical study of a humidification– dehumidification desalting system, Desalination, 94 (1993) 11. [7] Cioccllanti L, Savoretti A, Renze M, Caresana F, Comodi G. Design and test of a single effect thermal desalination plant using waste heat from m-CHP units. Appl Therm Eng 2015; 82:18–29. [8] Elminshawy NAS, Siddiqui FR, Sultan GI. Development of a desalination system driven by solar energy and low grade waste heat. Energy Convers Manage 2015; 103:28–35. [9] Mahmoud Ben Amara, Imed Houcine, Amenallah Guizani, Mohammed M. Maalej, Comparison of indoor and outdoor experiments on a newly designed air solar plate collector used with the operating conditions of a solar desalination process, Desalination 168 (2004) 81–88. [10] Hendrik Müller-holst, Solar Thermal Desalination Using the Multiple Effect Humidification (MEH) Method. Solar Desalination for the 21st Century, Springer, 2006 215–225.
ScienceDirect Energy Procedia 109 (2017) 253 – 260
International Conference on Recent Advancement in Air Conditioning and Refrigeration, RAAR 2016, 10-12 November 2016, Bhubaneswar, India
An Experimental Study on Water Harvesting from a Modified Window Air-Conditioner Purnendu Dalaia*, Prasant Nandab,Chinmaya Munda, Debasmita Mishrab, Abhijeet Guptac a
Department of Mechanical Engineering,CVRCE, Bhubaneswar, odisha,752054, India Department of mechanical engineering,VSSUT, Burla, sambalpur, odisha, 768018, India c Department of mechanical engineering, hi-tech institute of technology,bhubaneswar,odisha,752057, India b
Abstract
An experimental study of the performance of an air conditioning system, using the concept of humidification-dehumidification is presented and investigated. The technique (AWVP) relies on utilizing the moisture present in atmospheric air and to increase its content to certain extent. The water extracted through this technique is of good standard and can be used for drinking and other purposes. The test setup consists of four loops namely fresh water circuit, air circuit, refrigerant circuit and dirty water circuit. Certain operating parameters like volume flow rate of air, air inlet temperature after heating and relative humidity was varied and its effect on the performance of the system was studied and analyzed. © by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license © 2017 2017Published The Authors. Published by Elsevier Ltd. (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility ofthe organizing committee of RAAR 2016. Peer-review under responsibility of the organizing committee of RAAR 2016. Keywords:Humidification, Dehumidification, AWVP.
1. Introduction The present age is having a serious problem of rising temperature and there is also an adequate shortage of portable drinking water. Although we have enormous amount of water available in sea and oceans but it cannot be used when and where it is required. There are also lot of diseases which occurs due to drinking of bad quality water. This all can be avoided innear future by simply modifying and utilizing some of our existing technologies. The technique of Atmospheric Water Vapour Processing (AWVP) is very useful in hot and humid climate.Besides AWVP technique, the system also utilizes the vapour compression refrigeration system. The system setup consists of four loops, out of which one is closed one and other three are open loops.
1876-6102 © 2017 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of RAAR 2016. doi:10.1016/j.egypro.2017.03.058
254
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
Nomenclature T1 T2 T3 T4 T5 T6 T7 P V T W R1 R2
Dry Bulb Temperature (DBT) of atmospheric air. Wet Bulb Temperature (WBT) of atmospheric air. DBT of air after it is being heated by Heating Coil. WBT of air after it is being heated by Heating Coil. DBT of air after water spraying. WBT of air after water spraying. DBT of cooled air from A.C. Outlet. Power in Watts. Volume Flow rate in m3/s. time in minutes. Water collected in millilitre. Relative humidity of atmospheric air. Relative humidity of air after water spraying.
Nafey et al. [1, 2] analyzed the humidification and dehumidification desalination process mathematically with accompanied experiments under the effect of solar energy with different environmental and operating conditions. They concluded that the mathematical result was in good agreement with the experimental results. air flow rate, cooling water flow rate and total solar energy influenced the efficiency of the unit. They also concluded that the area of the solar water collector area affected the system’s productivity immensely. Amer et al. [3] mathematically and experimentally analyzed the humidification–dehumidification desalination system. They developed a system with water on an open cycle and air stream in closed cycle. They circulated the air with natural or forced circulation. They experimented with varying operating conditions using different packing materials. The heat and mass transfer coefficients were obtained experimentally and then fitted in forms of empirical correlations. They concluded that with increase in the mass flow rate, the productivity of the system increases. The temperature of the water at the condenser increases linearly with the water temperature at the humidifier inlet and decreased as the rate of flow of water decreased. A maximum productivity of 5.8 l/h has been obtained using wooden slate packing and with forced air circulation. Farsad and Behzadmehr [4] developed the balanced equation for the components .and did a thermodynamic analysis for a solar HDH desalination system. They calculated the amount of fresh water production with the developed equation and finished the sensitivity analysis with the main parameters was completed with the design of experimental method.Thus finding out the optimum condition of the desalination process.Parekh et al. [5] did a in depth technical review of solar desalination with multiple effect cycle and concluded that the solar desalination based on the humidification and dehumidification process presents the best method of solar desalination due to overall high efficiency. Younis et al. [6] theoretically designed a procedure to desalinate seawater in which they preheated brackish water using solar collectors and then brought them in contact with the inlet air in an evaporation column followed by a condensation stack for dehumidification. In the present work an attempt has been made to retrofit a window air conditioner to simultaneously generate cooling effect and drinking water from atmospheric air. Atmospheric air was initially humidified with low and poor quality water and good quality water was harvested from it, which is suitable enough for human consumption. * Corresponding author. Tel.: 9040200968 E-mail address:[email protected]
255
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
2. Experimental setup The experimental set up consists of four independent circuit named, fresh air circuit, dirty water circuit, refrigerant circuit and fresh water circuit. Out of these four loops, only the refrigerant loop was closed one, while other three are open loops. The block diagram of the experimental setup is given in Fig. 1.
5
1
2
15
16
13
10
3
4
6
7
8
9
14
12 11 Fig. 1. Experimental Setup of modified window air-conditioner Table 1: Various parts of experimental set up of modified window air conditioner with dimensions. S.NO 1 2 3, 4 5 6
7 8, 9
PART Window air Conditioner Duct Duct
SIZE,CAPACITY 1.5 tonne
S.NO 10
PART Blower
16*16 inch 16*10 inch
11 12
Humidification Point Duct
NA
13
Variac NA Fresh Water NA Collection Point Valve 2.5 inch
10*10 inch
14
Duct CS Pipe
10*2.5 inch 2.5inch, 300mm
15 16
Pressure Tapings Manometer Heating Coil Orifice Plate
SIZE,CAPACITY NA
NA to 1000 W 10 mm
256
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
3. Experimental Procedure x x
x
x x x
An old window AC was taken and necessary repair was done. Other parts are fabricated with care, keeping dimensions in mind. Then assembly of different parts were done as per the set up shown in Fig. 1. The blower was started initially and the valve was set full open so that volume flow rate becomes maximum. Then variac was switched on and was set at 60 volt, so that power supply becomes 240 W. It was left for few minutes, so that after few minutes steady conditions were obtained. Once steady conditions were obtained i.e. reading for temperature and volume flow rate of air were stabilized, window AC was started and test was conducted for a span of 20 minutes. The test was performed separately by spraying water once and separately by without spraying water. The temperatures were recorded at various collection points, where suitable arrangements were made for recording the temperature. The water generated from AC was collected at a point and was measured with the help of a measuring beaker. The same set of steps was performed for different volume flow rate of air and for different variac settings.
4. Results and Discussions The experiment was performed for test duration of 20 minutes, after the setup has achieved steady state. Several parameters like volume flow rate, power supply werevaried and readings were taken. The readings are presented in a tabular manner. Table 2: The different sets of data collected from conducting the experiment when power = 160W. P in watts
V in m3/s
160
0.00729
160
0.00623
160
0.00542
160
0.00729
160
0.00623
160
0.00542
Test Type Dry run Dry run Dry run Wet Run Wet Run Wet Run
Time in Sec
T1
T2
T3
T4
T5
T6
T7
20
33
26
42
29
32
24
10
Water Collected in ml 750
20
31
26
42
29
29
24
8
20
30
26
43
30
28
26
20
35
26
41
29
28
20
26
24
32
25
20
35
29
43
31
R1
R2
59
53
1025
68
67
10
1100
72
86
24
11
805
54
73
24
21
9
1270
84
75
30
28
11
1000
65
86
257
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
Table 3: The different sets of data collected from conducting the experiment when power = 200W. P in watts
V in m3/s
Test Type
200
0.00729
200
0.00623
200
0.00542
200
0.00729
200
0.00623
200
0.00542
Dry run Dry run Dry run Wet Run Wet Run Wet Run
Time in Sec
T1
T2
T3
T4
T5
T6
T7
20
32
25
44
29
29
23
10
Water Collected in ml 675
20
31
26
42
29
29
24
8
20
33
25
46
29
29
25
20
32
25
42
28
29
20
26
24
40
29
20
36
28
45
30
R1
R2
57
60
1025
68
66
10
1120
53
72
24
10
1050
57
66
24
22
10
1480
84
83
29
26
10
850
56
84
Table 4: The different sets of data collected from conducting the experiment when power = 240W. P in watts 240
V in m3/s 0.00729
240
0.00623
240
0.00542
240
0.00729
240
0.00623
240
0.00542
Test Type Dry run Dry run Dry run Wet Run Wet Run Wet Run
Time in Sec 20
T1
T2
T3
T4
T5
T6
T7
R1
R2
52
56
34.5
26
50
30
31
24
11
Water Collected in ml 625
20
29
24
45
29
28
25
8
1035
67
78
20
34
28
54
33
30
27
11
850
65
80
20
30
25
45
29
29
25
11
1250
66
72
20
28
24.5
42
29
25
23
11
1325
75
84
20
35
28
46
31
29
27
11
930
60
78
Analyzing the results following graphs were plotted and following conclusions were deduced. The graphs were plotted in Microsoft Excel.
258
Purnendu Dalai et al. / Energy Procedia 109 (2017) 253 – 260
Fig. 2. Effect of volume flow rate and power on fresh water collected, keeping Power= 160 W constant.
In the above Fig. 2, graph was plotted between volume flow rate and water collected, keeping power= 160 W constant. In dry run test, water collected was maximum for the volume flow rate=0.00542 m3/s, and least for the volume flow rate of 0.00729 m3/s. In the dry run, water collected rate increases as the volume flow rate decreases. While in wet run test, water collected rate first increases and then decreases sharply, and its maximum when the volume flow rate was 0.00623 m3/s. In the present case, as the volume flow rate increases, the effective heat transfer coefficient increases so a better cooling effect was achieved, and hence water production also increases. However, when volume flow rate was further increased, the residence time of air over the cooling coil decreases leading to a lower yield. In fact at higher volume flow rate, a slight decrease in relative humidity has been noticed.
Fig. 3. Effect of volume flow rate and power on fresh water collected, keeping Power= 200 W constant.
In the above Fig. 3 graph was plotted between volume flow rate and water collected, keeping power= 200 W constant. The graph follows the same trend as in previous graph, where power= 160 W, was kept constant. In dry run test, water collected was maximum for the volume flow rate=0.00542 m3/s, and least for the volume flow rate of 0.00729 m3/s. In the dry run, water collected rate increases as the volume flow rate decreases. While in wet run test, water collectedrate first increases and then decreases sharply, and its maximum when the volume flow rate was 0.00623 m3/s.
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Fig. 4 Effect of volume flow rate and power on fresh water collected, keeping Power= 240 W constant. The trend of water collection remain as par with the case, when power was 160 W. However the yield at higher volume flow rate in case of 240 W and for wet run case was found to be comparatively higher as compared with the dry run test due to better moisture absorption and higher heat transfer rate at higher temperature. The dehumidification done by the evaporator coils of window air conditioner gives us good quality water in which turbidity of collected water has gone down. 5. Conclusion In this paper a window air conditioner was modified to enhance the cooling effect and produce processcum drinking water.It was found that the amount of water collected depended on volume flow rate, cooling coil capacity, humidity, heat transfer coefficient and time of residence of air inside the window air conditioner. The water collection in all cases washigh for wet run test as compared to dry run test. Also the yield increases at higher temperature, this was due to the fact that at higher temperature water absorption capacity and heat transfer rate increases.The average water collection rate was 0.3 ml/s. The turbidity of water collected was much less than that used for spraying. The turbidity of water that is used for spraying and humidification was very high. It is translucent. But the water that we were getting from dehumidification done by the window air conditioner is transparent. This clearly shows that turbidity of collected water which can be used for drinking has tremendously gone down.
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6. References
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