A Study on the Prediction of the Optimum Performance of a Small-Scale Desalination System Using Solar Heat Energy
Abstract
:1. Introduction
2. System Configuration
2.1. Experimental Apparatus
2.2. Experimental Results
- y: freshwater generation (g/h)
- x: temperature of storage tank (K)
3. Simulation
3.1. Solar Radiation Data
3.2. Estimation of the Total Solar Radiation on Horizontal Surfaces
3.2.1. Formula for Estimating the Total Solar Radiation on Horizontal Surfaces
3.2.2. Comparison with the Measured Values of the Total Solar Radiation on Horizontal Surfaces
3.2.3. Solar Radiation on Inclined Surfaces
3.2.4. Solar Radiation on Inclined Surfaces and the Amount of Collected Heat
3.3. Calculation of the Amount of Fresh Water Generation
3.3.1. Heat Collecting Efficiency of the Solar Collector
3.3.2. Calculation and Verification of the Amount of Fresh Water Generation
3.4. Comparison of the Amount of Fresh Water Generation According to the Installation Angle of the Solar Collector
4. Conclusions
- (1)
- The actual amount of fresh water generation was discovered to be proportional to the temperature of solar heat storage during the daytime. The hourly solar heat storage temperature, as well as the hourly amount of fresh water generation, was also discovered to be linearly proportional to each other after the system reached its thermal normal state after the startup of its operation.
- (2)
- This study created a program for estimating the solar radiation on inclined surfaces which does not need any cloud cover information for the purpose of designing an estimation program for areas without any cloud cover information, which is required for existing solar heat tracking simulation algorithms. As a result of comparing the simulation results obtained using the program with the measured values, it was confirmed that they match each other quite well.
- (3)
- Hourly amounts of fresh water generation were estimated by applying an empirical formula derived as an experimental result by calculating the heat storage temperature of the solar thermal collector through the created solar heat tracking simulation program and, accordingly, it was confirmed that the estimation results were very similar to the experimental results after the system reached its thermal normal state.
- (4)
- The length of time required for the system to reach its thermal normal state was considered to be four hours by this study, and the estimation results were confirmed to show an error of approximately 10% in comparison with the experimental results except in the case where the temperature of the heat storage tank is 40 °C.
- (5)
- According to the simulation results, the largest annual amount of fresh water generation at the latitude (35.10°) of Busan was discovered when the solar thermal collector was installed at an angle of 30°. The largest seasonal amount of fresh water was generated at an angle of 45° in winter, at an angle of 30° in spring and fall, and at an angle of 15° in summer. This is thought to be due to the diverse monthly solar altitude angles.
Acknowledgments
Author Contributions
Conflicts of Interest
Nomenclature
Solar constant (1367 W/) | |
Total solar radiation on horizontal surfaces 9 W/) | |
Solar radiation on inclined surfaces (W/) | |
α | Solar altitude angel (°) |
flow rate of heat medium (kg/) | |
flow rate of sea water (kg/s) | |
Ta | Temperature of air (°C) |
To | Temperature of inlet of solar collector (°C) |
Ti | Temperature of outlet of solar collector (°C) |
TH | Temperature of Heated sea water (°C) |
TC | Temperature of Cold sea water (°C) |
Tm | Temperature of water storage tank (°C) |
Ti2 | Temperature of inlet of storage tank (°C) |
To2 | Temperature of outlet of storage tank (°C) |
heat transfer coefficient of sea water in storage tank (W/K) | |
heat transfer coefficient of heat medium in pipe (W/K) | |
Tdb,n | Drybulb temperature at n time (°C) |
RH | Relative humidity (%) |
Vw | wind velocity (m/s) |
tds | sunshine durations (h) |
γ | Solar azimuth angle (°) |
φ | Inclined angle of solar collector (°) |
Qab | Collected solar energy (W) |
Qloss | Heat loss (W) |
h | Convective heat transfer coefficient (W/m2K) |
r1 | Inner diameter of pipe (m) |
r2 | Outer diameter of pipe (m) |
k1 | Heat transfer coefficient of pipe (W/m∙K) |
k2 | Heat transfer coefficient of storage tank insulation (W/m∙K) |
L | Length of pipe (m) |
d | Diameter of storage tank (m) |
H | Height of storage tank (m) |
Ch | Specific heat of heat medium (kJ/kg K) |
Cw | Specific heat of sea water (kJ/kg K) |
η | Efficiency of solar collector (%) |
References
- Parekh, S.; Farid, M.M.; Selman, J.R.; Al-Hallaj, S. Solar desalination with a humidification-dehumidification technique-acomprehensive technical review. Desalination 2004, 160, 167–186. [Google Scholar] [CrossRef]
- Yang, H.K. Water Balance Change of Watershed by Climate Change. J. Korean Geogr. Soc. 2007, 42, 405–420. [Google Scholar]
- Dai, Y.J.; Zhang, H.F. Experimental investigation of a solar desalination unit with humidification and dehumidification. Desalination 2000, 130, 169–175. [Google Scholar] [CrossRef]
- Qiblawey, H.M.; Banat, F. Solar thermal desalication technologies. Desalination 2008, 220, 633–644. [Google Scholar] [CrossRef]
- Bahnemann, D. Photocatalytic water treatment: Solar energy applications. Sol. Energy 2004, 77, 445–459. [Google Scholar] [CrossRef]
- Li, C.; Goswami, Y.; Stefanakos, E. Solar assisted sea water desalination: A review. Renew. Sustain. Energy Rev. 2013, 19, 136–163. [Google Scholar] [CrossRef]
- Martinopoulos, G.; Ikonomopoulos, A.; Tsilingiridis, G. Initial evaluation of a phase change solar collector for desalination applications. Desalination 2016, 399, 165–170. [Google Scholar] [CrossRef]
- Horta, P.; Zaragoza, G.; Alarcón-Padilla, D.C. Assessment of the use of solar thermal collectors for desalination. Desalination Water Treat. 2015, 55, 2856–2867. [Google Scholar] [CrossRef]
- Yoon, K.; Yun, G.; Jeon, J.; Kim, K.S. Evaluation of hourly solar radiation on inclined surfaces at Seoul by Photographical Method. Sol. Energy 2014, 100, 203–216. [Google Scholar] [CrossRef]
- Khorasanizadeh, H.; Mohammadi, K.; Mostafaeipour, A. Establishing a diffuse solar radiation model for determining the optimum tilt angle of solar surfaces in Tabass. Iran. Energy Convers. Manag. 2014, 78, 805–814. [Google Scholar] [CrossRef]
- Corredor, L.M. Estimation of Solar Radiation Incident on Horizontal and Tilted Surfaces for 7 Colombian Zones. Int. J. Eng. Res. 2013, 2, 362–366. [Google Scholar]
- Al-Rawahi, N.Z.; Zurigat, Y.H.; Al-Azri, N.A. Prediction of hourly solar radiation on horizontal and inclined surfaces for Muscat/Oman. J. Eng. Res. 2011, 8, 19–31. [Google Scholar] [CrossRef]
- Zhang, Q.; Huang, J.; Lang, S. Development of typical year weather data for Chinese locations/Discussion. ASHRAE Trans. 2002, 108, 1063. [Google Scholar]
- Kim, H.Y.; Kim, J. Correlation to Predict Global Solar Insolation and Evaluation of that Correlation for Korea (I). New Renew. Energy 2016, 10, 30–35. [Google Scholar] [CrossRef]
- Cho, Y.; Kim, Y.; Chung, K.S. A study of Optimum Slope Angles of Fixed and Azimuth Tracking Solar Collectors by Region, Period and Year. In Proceedings of the SAREK Summer Annual Conference, Pyungchang, Korea, 23–25 June 2010. [Google Scholar]
- Yuan, G.; Wang, Z.; Li, H.; Li, X. Experimental study of a solar desalination system based on humidification-dehumidification process. Desalination 2011, 277, 92–98. [Google Scholar] [CrossRef]
- Al-Kharabsheh, S.; Yogi, D. Analysis of an innovative water desalination system using low-grade solar heat. Desalination 2003, 156, 323–332. [Google Scholar] [CrossRef]
- Orfi, J.; Laplante, M.; Marmouch, H.; Galanis, N.; Benhamou, B.; Nasrallah, S.B.; Nguyen, C.T. Experimental and theoretical study of a humidification-dehumidification water desalination system using solar energy. Desalination 2004, 168, 151–159. [Google Scholar] [CrossRef]
- Jürges, W. Der Warmeubergang an Einer Ebenen Wand, 2nd ed.; R. Oldenbourg: München, Germany, 1924. [Google Scholar]
- Park, S.M.; Kim, J. Correlation to Predict Global Solar Insolation and Evaluation of that Correlation for Korea (II). New Renew. Energy 2016, 12, 24–29. [Google Scholar] [CrossRef]
- Jo, D.K.; Yun, C.Y.; Kim, K.D.; Kang, Y.H. A study on the estimating solar radiation using hours of bright sunshine for the installation of photovoltaic system in Korea. J. Korean Sol. Energy Soc. 2011, 31, 72–79. [Google Scholar] [CrossRef]
- Basunia, M.A.; Yoshio, H.; Abe, T. Simulation of Solar Radiation Incident on Horizontal and Inclined Surfaces. J. Eng. Res. TJER 2012, 9, 27–35. [Google Scholar] [CrossRef]
- Kim, J.B.; Rhie, S.M.; Yoon, E.S.; Lee, J.K.; Joo, M.C.; Lee, D.W.; Kwak, H.Y.; Baek, N.C. Thermal Characteristics of Domestic Solar Collector for Low-Themperature Applications. J. Korean Sol. Energy Soc. 2007, 27, 155–160. [Google Scholar]
Classification | Details | |
---|---|---|
Place of experiment | Busan (Latitude 35.10°) | |
Period of experiment | 11 April 2016–6 May 2016 | |
Hours of solar heat storage | 7:00 a.m.–7:00 p.m. (12 h) | |
Hours of desalination | 7:00 p.m.–7:00 a.m. (12 h) | |
Installation angle | 45° | |
Operation conditions | Amount of incoming cooling water: 0.8 L/min Temperature of hot water (seawater): 70 °C, 60 °C, 50 °C, 40 °C Temperature of cooling water (seawater): 15 °C | |
Solar collector | Type | Flat type |
Size | 1180 × 2400 × 92 mm | |
Quantities | 3 panel | |
Glass | Low-iron glass (transmit rate: 91.7%) with 4 mm thickness | |
Absorber | Titanium coated copper plate (emission rate : 4 ± 1%, Absorption rate : 95 ± 1%) with 0.2 mm thickness | |
Insulation | Glass wool 0.040 W/mK with 40 mm thickness (bottom) PE form 0.035 W/mK with 15 mm thickness (side) | |
Pipe | φ22.2 mm × 2 EA and φ8 mm × 10 EA | |
Solar storage tank | 300 L (φ650 × 900H, 100 mm glass wool insulation) | |
Etc. | Pump (7 m, 50 LPM, inline pump), 15 mm HDPE (High Density Polyethylene) pipe with 40 mm insulation |
Instrumentation/Type | Range | Accuracy |
---|---|---|
Data logger (20 Channel) | −100 to 1370 °C | ±0.8 °C |
Temperature sensor/K-type thermocouple | 0−200 °C | ±0.75% |
Flow control valve Floating flowmeter | 0.03−30 /h | ±2% |
Scale/electronic | 0−2000 g | ±0.2% |
Area | Gwangju | Daegu | Daejeon | Busan | Seoul | Ulsan | Jeju |
---|---|---|---|---|---|---|---|
Latitude (°) | 35.17 | 35.83 | 36.37 | 35.10 | 37.57 | 35.58 | 33.51 |
Month | Measured Value (A, MJ/m2 day) | Simulation Result (B, MJ/m2 day) | A/B |
---|---|---|---|
1 | 10.13 | 10.43 | 0.97 |
2 | 11.50 | 11.52 | 0.97 |
3 | 15.07 | 15.42 | 0.96 |
4 | 17.25 | 17.83 | 0.96 |
5 | 19.64 | 20.05 | 0.98 |
6 | 16.69 | 16.51 | 1.01 |
7 | 17.33 | 16.52 | 1.05 |
8 | 16.59 | 16.39 | 1.01 |
9 | 14.32 | 14.41 | 1.01 |
10 | 12.76 | 12.80 | 1.00 |
11 | 9.58 | 9.86 | 0.98 |
12 | 8.57 | 9.27 | 0.96 |
Average | 14.12 | 14.25 | 0.99 |
Area | Gwangju | Daegu | Daejeon | Busan | Seoul | Ulsan | Jeju |
---|---|---|---|---|---|---|---|
A/B | 1.04 | 0.89 | 1.13 | 0.99 | 0.89 | 0.96 | 1.07 |
Parameter | Value/Type |
---|---|
Area | Daejeon |
Installation angle | 30° |
Installation direction | Due South |
Number of Solar collection sheets | 3 EA |
Solar collection area per sheet | 2.83 m2 |
Flow rate per sheet | 0.02 kg/s |
Hot water storage tank (L) | 300 |
Month | Daily Average Solar Radiation (MJ/ m2 day) Jo et al. Predicted | Daily Average Solar Radiation (MJ/ m2 day) Present Study | Average Efficiency (η) | Amount of Collected Heat (MJ/ m2 day) |
---|---|---|---|---|
1 | 12.28 | 13.18 | 0.48 | 6.26 |
2 | 14.47 | 14.54 | 0.50 | 7.28 |
3 | 16.56 | 17.12 | 0.53 | 9.09 |
4 | 18.11 | 17.26 | 0.56 | 9.60 |
5 | 16.88 | 19.00 | 0.51 | 9.71 |
6 | 16.96 | 17.00 | 0.55 | 9.37 |
7 | 13.79 | 13.42 | 0.49 | 6.61 |
8 | 13.86 | 14.50 | 0.57 | 8.23 |
9 | 15.19 | 14.74 | 0.56 | 8.29 |
10 | 15.23 | 15.07 | 0.50 | 7.60 |
11 | 12.02 | 12.55 | 0.44 | 5.59 |
12 | 11.81 | 12.43 | 0.41 | 5.10 |
Average | 14.76 | 15.07 | 0.51 | 7.73 |
Item | Flat-Plate Type | Single Vacuum Tube | Reflector Double Vacuum Tube |
---|---|---|---|
0.771 ± 0.058 | 0.721 ± 0.007 | 0.664 ± 0.078 | |
5.091 ± 0.611 | 1.483 ± 0.758 | 2.829 ± 1.996 | |
0.0048 ± 0.0071 | 0.0055 ± 0.0047 | −0.0005 ± 0.0126 |
Temperature | 70 °C | 60 °C | 50 °C | 40 °C |
---|---|---|---|---|
Difference Rate | 95.26% | 101.98% | 91.92% | 93.53% |
Month | 0° | 15° | 30° | 45° | 60° | 75° | 90° |
---|---|---|---|---|---|---|---|
1 | 34 | 78 | 111 | 127 | 126 | 109 | 80 |
2 | 58 | 96 | 119 | 127 | 119 | 98 | 66 |
3 | 150 | 185 | 199 | 194 | 172 | 136 | 91 |
4 | 256 | 275 | 275 | 258 | 227 | 182 | 128 |
5 | 368 | 377 | 367 | 342 | 304 | 254 | 196 |
6 | 371 | 374 | 363 | 341 | 308 | 267 | 221 |
7 | 438 | 443 | 433 | 413 | 380 | 339 | 292 |
8 | 483 | 495 | 490 | 471 | 440 | 399 | 349 |
9 | 396 | 422 | 430 | 421 | 398 | 362 | 315 |
10 | 291 | 337 | 362 | 365 | 352 | 322 | 278 |
11 | 133 | 192 | 228 | 244 | 240 | 219 | 182 |
12 | 40 | 88 | 124 | 142 | 144 | 128 | 99 |
Total (g/year) | 92,200 | 102,637 | 106,885 | 105,150 | 98,011 | 85,911 | 70,185 |
© 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Share and Cite
Jun, Y.-J.; Song, Y.-H.; Park, K.-S. A Study on the Prediction of the Optimum Performance of a Small-Scale Desalination System Using Solar Heat Energy. Energies 2017, 10, 1274. https://doi.org/10.3390/en10091274
Jun Y-J, Song Y-H, Park K-S. A Study on the Prediction of the Optimum Performance of a Small-Scale Desalination System Using Solar Heat Energy. Energies. 2017; 10(9):1274. https://doi.org/10.3390/en10091274
Chicago/Turabian StyleJun, Yong-Joon, Young-Hak Song, and Kyung-Soon Park. 2017. "A Study on the Prediction of the Optimum Performance of a Small-Scale Desalination System Using Solar Heat Energy" Energies 10, no. 9: 1274. https://doi.org/10.3390/en10091274