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Fig. 5. Variation of humidifier effectiveness with MR at a heat input of 5.6 kw.

Figure 5 Variation of humidifier effectiveness with MR at a heat input of 5.6 kw.

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e The system involved operates under steady-state conditions. “In both of these figures, T, T,, and Tg, are the water temperature, wet bulb temperature and dry-bulb temperature of the air, respectively.
e The system involved operates under steady-state conditions. “In both of these figures, T, T,, and Tg, are the water temperature, wet bulb temperature and dry-bulb temperature of the air, respectively.
2.3. Mathematical modeling tank is then heated and sprayed in the humidifier where part of it evaporates and the unevaporated seawater is collected, ducted and re- circulated back to the tank, to close the water loop.
2.3. Mathematical modeling tank is then heated and sprayed in the humidifier where part of it evaporates and the unevaporated seawater is collected, ducted and re- circulated back to the tank, to close the water loop.
Fig. 3. A photograph showing main components of the experimental set-up.
Fig. 3. A photograph showing main components of the experimental set-up.
Fig. 4. Impact of mass ratio on gain output ratio at a different total heat input. Fig. 4 illustrates the validation results obtained for the system GOR at different mass ratio and total heat input. As observed in this figure, the gain output ratio increases with the mass flow rate ratio, which has a direct relationship with water flow rate. Increasing the feed water flow rate generates more vapor in the humidifier, and consequently more condensate from the dehumidifier, resulting in higher system GOR, which has a direct relationship to fresh water flow rate. The system GOR is also found to decrease with increasing total heat input. This is because the energy input to the system has an inverse re- lationship with GOR, as presented in Eq. (10). The presented model is observed to be in a good agreement with the experimental data as the maximum model deviation is calculated to be within + 5% of the ex- perimental values. Results also showed that the system has an experi- mental and theoretical maximum GOR of 0.4 and 0.42, respectively, at the mass flow rate ratio of 1.81. The low experimental GOR value is due to the poor humidifier effectiveness (25 to 54%), as shown in Fig. 5, which directly translates to low evaporation rates, and consequently low system GOR values. Next, we defined the limits for components effectiveness, where the system performance will be explored within The uncertainty is usually evaluated in the calculated results ob- tained from experimental investigations. Since we used temperature sensors and flowmeters to measure the conditions of operating para- meters, it is essential to evaluate the effect of these measured values on
Fig. 4. Impact of mass ratio on gain output ratio at a different total heat input. Fig. 4 illustrates the validation results obtained for the system GOR at different mass ratio and total heat input. As observed in this figure, the gain output ratio increases with the mass flow rate ratio, which has a direct relationship with water flow rate. Increasing the feed water flow rate generates more vapor in the humidifier, and consequently more condensate from the dehumidifier, resulting in higher system GOR, which has a direct relationship to fresh water flow rate. The system GOR is also found to decrease with increasing total heat input. This is because the energy input to the system has an inverse re- lationship with GOR, as presented in Eq. (10). The presented model is observed to be in a good agreement with the experimental data as the maximum model deviation is calculated to be within + 5% of the ex- perimental values. Results also showed that the system has an experi- mental and theoretical maximum GOR of 0.4 and 0.42, respectively, at the mass flow rate ratio of 1.81. The low experimental GOR value is due to the poor humidifier effectiveness (25 to 54%), as shown in Fig. 5, which directly translates to low evaporation rates, and consequently low system GOR values. Next, we defined the limits for components effectiveness, where the system performance will be explored within The uncertainty is usually evaluated in the calculated results ob- tained from experimental investigations. Since we used temperature sensors and flowmeters to measure the conditions of operating para- meters, it is essential to evaluate the effect of these measured values on
Components effectiveness valid for recirculation system. Table 2 and outside the defined limits of the component effectiveness values.
Components effectiveness valid for recirculation system. Table 2 and outside the defined limits of the component effectiveness values.
Fig. 6. Impact of mass ratio on gain output ratio at different components effectiveness values (basic cycle): (a) eden = 0.50, and each = 0.85 Fig. 7 shows the influence of mass ratio on GOR at different com- ponents effectiveness values for zero brine recirculation (basic cycle) and different percentages of brine recirculation (modified cycle). The GOR of the system is noticed to jump from a maximum of 0.35 (zero recirculation) to a value of approximately 0.7 (100% brine recircula- tion), representing about 100% improvement in the system energy performance. The effect of percentage brine recirculation is also pre- sented in the figure, where we noticed an increase in system GOR due to
Fig. 6. Impact of mass ratio on gain output ratio at different components effectiveness values (basic cycle): (a) eden = 0.50, and each = 0.85 Fig. 7 shows the influence of mass ratio on GOR at different com- ponents effectiveness values for zero brine recirculation (basic cycle) and different percentages of brine recirculation (modified cycle). The GOR of the system is noticed to jump from a maximum of 0.35 (zero recirculation) to a value of approximately 0.7 (100% brine recircula- tion), representing about 100% improvement in the system energy performance. The effect of percentage brine recirculation is also pre- sented in the figure, where we noticed an increase in system GOR due to
Fig. 7. Effect of MR on GOR for zero brine recirculation (basic cycle) and different percentages of brine recirculation (modified cycle).
Fig. 7. Effect of MR on GOR for zero brine recirculation (basic cycle) and different percentages of brine recirculation (modified cycle).
g. 8. Influence of mass ratio on gain output ratio at different components effectiveness for different percentages of brine recirculation (modified cycle).
g. 8. Influence of mass ratio on gain output ratio at different components effectiveness for different percentages of brine recirculation (modified cycle).
Fig. 9. effect of mass ratio on gain output ratio at different components effectiveness for different percentages of brine recirculation (modified cycle)
Fig. 9. effect of mass ratio on gain output ratio at different components effectiveness for different percentages of brine recirculation (modified cycle)
Fig. 10. Impact of mass ratio on Gain output ratio at different components effectiveness for different percentages of brine recirculation (modified cycle)
Fig. 10. Impact of mass ratio on Gain output ratio at different components effectiveness for different percentages of brine recirculation (modified cycle)
Comparison between various HDH cycles.
Comparison between various HDH cycles.
Effects of increasing inlet water temperature on water production cost of HDH plant.
Effects of increasing inlet water temperature on water production cost of HDH plant.
Capital investment cost for HDH plant [23,25].
Capital investment cost for HDH plant [23,25].
Comparison of the current systems with reverse osmosis (RO) desalination system.
Comparison of the current systems with reverse osmosis (RO) desalination system.
Fig. 11. Influence of electricity cost on the fresh water cost.
Fig. 11. Influence of electricity cost on the fresh water cost.
Uncertainty values for the effect of changing heat input at MR = 1.36.
Uncertainty values for the effect of changing heat input at MR = 1.36.
Components effectiveness valid for recirculation system at MR = 1.0.
Components effectiveness valid for recirculation system at MR = 1.0.
Components effectiveness valid for recirculation system at MR = 1.5.
Components effectiveness valid for recirculation system at MR = 1.5.
Components effectiveness valid for recirculation system at MR = 3. Table B5
Components effectiveness valid for recirculation system at MR = 3. Table B5
Related topics:
Water and wastewater treatmentWast heat recoverySeawater DesalinationHumidification SystemHumidification and dehumidification
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