الفهرس 
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Abstract
Cold seawater is an important renewable energy source that can be used in the field of air
conditioning. In the northern Arabian Gulf, the depth of seawater ranges from 40 m to 60
m, with seawater temperatures ranging from 15 °C to 27°C, which is insufficient for use
as a direct seawater method for air conditioning in high-temperature conditions. In
this study, two single effect LiBr-H2O absorption air conditioning systems that utilize
seawater are studied. The seawater is used in the first system for cooling the cooling water
required for both the condenser and the absorber. While the second system utilizes
seawater for cooling. Cooling water is required for the condenser and absorber as well as
the air precooling process. The generator temperature varied from 90oC to 110oC.
Completer thermodynamics analysis is performed using EES software and the results
show that the coefficient of performance for two systems is the same while a considerable
reduction of the equipment size is prevailed due to air precooling.
By using the ANSYS 20 program multiple models of heat exchangers were built as air
precooling utilizing seawater to cool the returned air from the room, Several cases were
investigated depending on the number of tubes, inline and staggered arrangement, rows
and columns, pipe diameter, and material of the heat exchanger. In this study, a twodimensional numerical simulation model of crossflow for a 20-tube bank in a staggered
arrangement with a diameter of 25 mm was investigated, with the pitch ratio SL/D and
ST/D as 1.5 and 1.25 respectively. The air inlet velocity ranged from 2 to 5 m/s, the air
inlet temperature is 28oC, and the seawater temperature of 21oC was considered.
This study summarized the numerical study to predict the performance of
a heat exchanger as an air precooler by utilizing the seawater as a cold stream. The effect
of tube bank arrangement is also investigated. ANSYS 20 was applied for the numerical
simulation, and the best results obtained of the temperature after the air precooling coil is 22.75oC that resulting in the efficiency of the air conditioning system maximum
improvement by 37.5 %. By comparing the feasibiulity of using heat exchanger for air
cooling by seawater, with conventional and absorption system which cool by cooling
tower and by seawater it seems that short economic payback period for the absorption
system with precooling, it’s better than the other systems.