Experimental and Numerical Analysis of a PCM-Supported ...

More documents

Recommendations

Info

78cm; Top: Evaporator, Bottom: Condenser Figure 6.4: Evolution of inlet and outlet liquid and gas temperatures for empty 135 spheres packing height 78cm; Top: Evaporator, Bottom: Condenser Figure 6.5: Comparison between measured and simulated accumulated 136 hourly productivities Figure 6.6: Time evolution of PCM temperature along the packed height 138 Figure 6.7: Evolution of liquid temperature along the packed height 139 Figure 6.8: Time evolution of gas temperature along the packed height 139 Figure 6.9: Time evolution of water vapor concentration along the packed 140 height Figure 7.1: Effect of packing size on the evaporation rate 143 Figure 7.2: Effect of packing size on specific surface area of the packed bed 143 Figure 7.3: Effect of packing size on the pressure drop of the gas 144 Figure 7.4: Effect of column aspect ratio on the evaporation rate, V bed =const. 146 Figure 7.6: Effect of column aspect ratio on the evaporation rate, H= 2m 147 Figure 7.5: Effect of column aspect ratio on the evaporation rate, H= 1m 148 Figure 7.7: Effect of inlet hot water temperature on the evaporation rate 149 Figure 7.8: Effect of inlet air temperature on the evaporation rate 150 Figure 7.9: Effect of air/water mass flow ratio on the evaporation rate 151 Figure 7.10: Effect of packing media properties on the evaporation rate 153 Figure 7.11: Effect of hot water flow rate on the evaporation rate of different 153 packing media Figure 7.12: Effect of inlet cooling water temperature on the condensation rate 155 Figure 7.13: Effect of inlet air temperature on the condensation rate 156 Figure 7.14: Effect of water to air mass flow ratio on the PF productivity factor 157 and NTU Figure 7.15: Effect of air to water mass flow ratio on the condensation rate 158 Figure 7.16: Effect of solid packing media on hourly productivity 159 Figure 7.17: Effect of PCM thermal conductivity on condensation rate under 160 different cooling water mass flow rates Figure 7.18: Effect of PCM thermal conductivity on condensation rate under 161 different inlet cooling water Figure 8.1: Selected geographical locations in Egypt 163 Figure 8.2: Daily and seasonal variations of weather conditions in Al-Arsh and 164 Al-Kharga, Egypt Figure 8.3: Effect of brine concentration ratio on the average-yearly distillate 166 rate and GOR Figure 8.4: Effect of PCM thermal buffer volume on the average-yearly daily 167 distillate for Al-Arish Figure 8.5: Effect of PCM thermal buffer volume on the average-yearly daily 168 distillate for Al-Kharga Figure 8.6: Effect of solar collector area on the average-yearly daily distillate 168 rate under different climatic conditions x
Figure 8.7: Effect of air to hot water mass flow rate ratio on the average-yearly 169 daily distillate rate and GOR Figure 8.8: Effect of cooling water to air flow rate ratio on the average-yearly 170 hourly distillate production and GOR Figure 8.9: Comparison between water and PCM as a storage medium 171 Figure 8.10: Effect of operational temperature range on sensible and latent 172 heat storage Figure 8.11: Histogram of hourly variation of inlet water temperature to the 173 PCM-storage over one year for Al-Arish city with 3m3 thermal storage Figure 8.12: Effect PCM melting temperature in the external thermal buffer 174 List of Tables Table 1.1: Characteristics for various desalination Technologies 5 Table 1.2: Type of renewable energy supply system and specific water cost 8 Table 2.1: Design parameters range of AQUASOL II 44 Table 5.1: Chosen variable parameters for experiments and range of values 110 Table 5.2: Basic sets of designed experiments according to boundary 110 conditions Table 5.3: Average values for inlet and outlet liquid and gas temperatures and 114 productivities during steady state operation conditions Table 6.1: Implementation of energy and mass balance equations using the 130 ”pdepe” MATLAB function Table 6.2: Specified boundary and operating conditions for model validation 131 Table 6.3: Measured and simulated total productivities 132 Table 6.4: Inlet and geometrical parameters within a sample simulation run 137 Table 7.1: Reference boundary conditions for the evaporator and condenser 142 Table 7.2: Effect of different packing media on the evaporation rate 152 (Mhw=1000 [l/h]) Table 7.3: Effect of different packing media on the condensation rate 159 (Mcw=1000 [l/h]) Table 7.4: Design recommendations for the evaporator and condenser to 162 produce 1000 [l/day] fresh water, inlet hot water temperature= 83°C Table 8.1: Specified baseline boundary and operating conditions 165 List of Frames Frame 2.1: Desirable properties of latent heat storage materials ............................. 23 xi
Page 1: Technische Universität München In
Page 4 and 5: It is my pleasure to thank Prof. Th
Page 6 and 7: Contents List of figures ..........
Page 8 and 9: 5.3 Functional description ........
Page 10 and 11: List of Figures Figure 1.1: Cost br
Page 14 and 15: xii
Page 16 and 17: m Mass flow rate; [kg.s -1 ] m eva
Page 18 and 19: ed c coll cond cw d d e or eff evap
Page 20 and 21: 1 Introduction The first part of th
Page 22 and 23: summarized in figure (1.2). Thermal
Page 24 and 25: 1.3.2 Selection criteria of desalin
Page 26 and 27: of energy storage or hybridization
Page 28 and 29: Desalination development focuses on
Page 30 and 31: Introduction of the indirect type s
Page 32 and 33: 2 Literature Survey 2.1 Introductio
Page 34 and 35: There is actually a commercial prod
Page 36 and 37: Q m H c ( T T1) c ( T 2 T ) (2.2)
Page 38 and 39: (solid-liquid) have a storage densi
Page 40 and 41: (iii) a sharp melting temperature.
Page 42 and 43: melt and freeze without segregation
Page 44 and 45: However, the stored heat is less va
Page 46 and 47: parameters on the heat transfer and
Page 48 and 49: categories. The first category is b
Page 50 and 51: to 550 kWh/m 3 of distilled water a
Page 52 and 53: The enthalpy and humidity of the sa
Page 54 and 55: Air mass flow rate [kg/h] GOR [-] 1
Page 56 and 57: On the other hand, the efficiency o
Page 58 and 59: 2.8.4.2 Effect of air to water mass
Page 60 and 61: distillate rate. The system was not
Page 62 and 63:
were; EnviPac Gr.1, 32 mm, and VFF
Page 64 and 65:
Figure 2.15: Height versus air temp
Page 66 and 67:
The performance of the condenser is
Page 68 and 69:
Klausner and Mei [136] described a
Page 70 and 71:
The impact of the collector cost ca
Page 72 and 73:
exchanger and energy storage in one
Page 74 and 75:
3 Scope of the Study This chapter p
Page 76 and 77:
packing where it gets in direct con
Page 78 and 79:
In fact there is a tradeoff between
Page 80 and 81:
The energy flow between all and eac
Page 82 and 83:
4 Theoretical Analysis and Modeling
Page 84 and 85:
The two-energy equation models whic
Page 86 and 87:
solid-liquid phase change inside th
Page 88 and 89:
assumed by conduction in both axial
Page 90 and 91:
the air pressure drop ∆P per unit
Page 92 and 93:
evaporation rate per unit volume of
Page 94 and 95:
where β t , β c , ρ ref , c ref
Page 96 and 97:
the viscous transport and introduce
Page 98 and 99:
liquid and solid phases, respective
Page 100 and 101:
4.2.3.3 Liquid and gas hold-ups Liq
Page 102 and 103:
Several models and approaches for m
Page 104 and 105:
where G=ρU d /ε g is the pore mas
Page 106 and 107:
k k eff s 1 3 2 (4.55) This cor
Page 108 and 109:
uncertainties associated with the f
Page 110 and 111:
1 2 (4.62) d1 capp c2 c1 c2 1
Page 112 and 113:
[58] evaluated the cooling tower ai
Page 114 and 115:
1 exp NTU 1 C r, cond cond (4
Page 116 and 117:
A HE QHE U T HE LM (4.81) Where Q
Page 118 and 119:
c M f b (4.86) M b S S f where r
Page 120 and 121:
that form the study logical foundat
Page 122 and 123:
5 Experimental Analysis This chapte
Page 124 and 125:
5.2 Measuring Techniques K-type the
Page 126 and 127:
The product condensed water was mea
Page 128 and 129:
operating limits. In light of the l
Page 130 and 131:
In the last two cases, the inlet ho
Page 132 and 133:
performance and its threshold value
Page 134 and 135:
It could be interpreted that this p
Page 136 and 137:
Evaporator Condenser Figure 5.8: Av
Page 138 and 139:
within the inaccuracy margins. The
Page 140 and 141:
The last two cases of boundary cond
Page 142 and 143:
natural air flow in the system. In
Page 144 and 145:
6 Model Implementation and Validati
Page 146 and 147:
x t u x u 0 0 , (6.5) and for a s
Page 148 and 149:
Next time step validation were the
Page 150 and 151:
The evaporator and condenser both w
Page 152 and 153:
Figure 6.2: Evolution of inlet and
Page 154 and 155:
Figure 6.4: Evolution of inlet and
Page 156 and 157:
temperature is at its maximum level
Page 158 and 159:
Bottom Top Figure 6.7: Evolution of
Page 160 and 161:
7 Parameters Analysis of the Evapor
Page 162 and 163:
Figure 7.1: Effect of packing size
Page 164 and 165:
e 0.45 kPa under natural convection
Page 166 and 167:
aspect ratio under constant bed vol
Page 168 and 169:
Figure 7.7: Effect of inlet hot wat
Page 170 and 171:
well as the time required to reach
Page 172 and 173:
Figure 7.10: Effect of packing medi
Page 174 and 175:
40°C respectively. This gives flex
Page 176 and 177:
the condensate rate, productivity f
Page 178 and 179:
esult, rather than PCM media which
Page 180 and 181:
Figure 7.18: Effect of PCM thermal
Page 182 and 183:
8 Optimization of HDH plant In this
Page 184 and 185:
The MATLAB model describes how the
Page 186 and 187:
less steep than that of the distill
Page 188 and 189:
8.3.4 Effect of hot water flow rate
Page 190 and 191:
storage materials and thus it can h
Page 192 and 193:
for latent heat storage would be ob
Page 194 and 195:
When T m becomes sufficiently highe
Page 196 and 197:
9 Summary and conclusions 9.1 Summa
Page 198 and 199:
productivities at any cooling water
Page 200 and 201:
[13] Vafai K., Sozen M. An investig
Page 202 and 203:
[48] Crone S., Bergins C., and Stra
Page 204 and 205:
[79] Tiwari G.N. and Yadav Y.P. (78
Page 206 and 207:
[109] Mehling H., Hiebler S. and Zi
Page 208 and 209:
[139] Belessiotis V, Delyannis E (2
Page 210 and 211:
Appendices Appendix A A1. PCM Therm
Page 212 and 213:
A3. Constants and Thermo-physical p
Page 214 and 215:
From the above correlation, the con
Page 216 and 217:
The Ergun analogy factor J h repres
Page 218 and 219:
Equation (C.7) represents an overal
Page 220 and 221:
Appendix D D1. Cooling tower theory
Page 222 and 223:
A m w = the plan or cross sectiona
show all

Experimental and Numerical Analysis of a PCM-Supported ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?