الفهرس 
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Abstract
Early devices of solar desalination had drawbacks of poor utilization of condensation heat and low thermal efficiency due to the large heat losses from the glass cover, under which the condensation occurs. Moreover, it is impossible for them to lift the evaporation temperature and decrease the condensation temperature at the same time since evaporation and condensation take place at the same time. Multi-stage flash (MSF) and reserve Osmosis (RO) are two important desalination processes used at present. Large-size installation producing millions of gallons of fresh water are in operation using these techniques, which need large amounts of basic thermal and/or electrical energy for fresh water production from seawater or brackish water. It has been shown that the humidification-dehumidification process could be an efficient and economical method of desalination.
An experimental humidification system for water desalination has been built with a channel containing material of humidifier. This humidifier`s material can be easily replaced to test the effect of different humidifier`s materials on the system performance. First type is cooling cell pad, it`s artificial type, and it manufactured from pulp of wood tree. And the second type is natural, it`s name (Luffa of date palm). Feature of these type are: 1- To provide a very high surface area to volume ratio, 2- Self-cleaning, 3- To minimize blockage of airflow, and 4- To resist rotting.
The closed air cycle humidification-dehumidification system is used for water desalination in the present study. The forced circulated air was heated and humidified by the hot water obtained from an electrical heater. The water and air temperature ranges used in this investigation are corresponding to that the project is the assessment of data, which permits humidifier evaluation. In the experimental work, the inlet water temperature to the humidifier range between 27to 490C, the inlet air temperature range between 30 to 400C, the water flow rates through the humidifier and the air cooler were changed in the range of 14 to 92 kg/h and 105 to 27 kg/h respectively, the air flow rate through the system was 70 to 185 kg/h, the inlet cooling water temperature used were 230C.
from the experimental observations the main relationships between the different variables were extracted withen the operation ranges used in the present study; it was found that:
1- Both coefficient of performance and system productivity increase with the temperature of inlet water into the humidifier under four different water-to-air mass flow rate ratio.
2-Temperature has a strong influence on water production and coefficient of performance if the conditions of condensation are not changed.
3-Increasing both the inlet water and air temperatures to humidifier is better than if each is increased individually.
4-Increasing both water and air flow rates through the system will increase the desalinated water product rate.
5-The cooling cell pad humidifier is better than luffa of date palm in productivity and system coefficient of performance. It is found that Md/Ma for cooling cell pad increases to 214.5% when Ma=70 kg/h.
6-A constant productivity is observed at Ma=70kg/h,Mwl=0.4&0.5 and ta1=400C between tw1=27 and 360C.
7-In case of Ma = 100kg/h,Mw1=0.5, and ta1350C, the system productivity Md/Ma for luffa approaches to the productivity of cooling cell pad when tw1=430C.
8- Generally the system productivity of cooling cell pad is better than luffa of data palm for all values of Ma1
9- In case of Ma=100 kg/h and Mw1/Ma =0.5, it can be seen that the system productivity of luffa approaches to the value of the cooling cell pad at tw1=41.70C.
10- In case of Ma=184 kg/, ta1=410C and tw1 = 49 0C, the system productivity of luffa approaches to the other type at Mw1/Ma=0.5.