Performance Evaluation of a Solar Humidification – Dehumidification Desalination Unit

الملخص

This paper is to investigate the use of solar
energy in desalination by humidification and dehumid-
ification process (HD). Here, a proposal for the desalination
unit has been come out with cylindrical shape containing the
evaporator in the middle and surrounded by the condenser.
The hot feed water coming from the solar thermal system is
sprayed at the top of the evaporator where the air flows
from the bottom. In the evaporator the air is humidified
until it gets out saturated, then introduced to the condenser,
where it is dehumidified to obtain the fresh water and
circulated back to the evaporator. Practically there are
many parameters influence on the performance of this
desalination unit, which are environmental, design and
operational. In the current study these parameters are taken
in consideration to formulate mathematical models which
govern the performance of the main components of this unit,
which are the evaporator, the condenser and the solar
thermal system. The deduced mathematical models have
been interpreted in many programs in visual basic language
as a computer software. This software contains many pages
which help in introducing and analyzing the most influential
parameters. In this case many operational parameters have
been studied such as feed water temperature, mass flow rate
and salinity, in addition to cooling water mass flow rate and
inlet temperature, as well as quantity of solar irradiance
with others. At these inputs many outputs have been
obtained which are related to the performance of the
desalination unit such as fresh water productivity, energy
consumption, humidifier volume, recovery ratio and gain
output ratio.