الفهرس 
الغلافOnly 14 pages are availabe for public view
 |  | from | 184 |  |  |
| | | from | 184 | | |
Abstract
In this work, the thermal and environmental investigations for split air
conditioner with capacity 1.5TR using low global warming potential (LGWP)
refrigerants as alternatives to the present R22 are examined experimentally at
different range of evaporator air velocities and evaporator air inlet temperatures.
The experiments are conducted at evaporator air inlet temperatures of 31°C, 38°C
and 48°C, the air passes over evaporator coil with velocity of 0.5 to 1.6 mls. The
study parameters such as different evaporator air temperature, discharge
temperature, cooling load, electrical compressor power, coefficient of
performance, indirect global warming parameter and total equivalent warming
parameter are investigated. The experimental results indicate that refrigerant
R152a has the higher thermal performance than R22 andR290. The coefficient
of performance of R152a is higher than that of R22 by 44.92% at a certain
evaporator air velocity is 1.2 mls and the evaporator air inlet temperature is 31°C.
The refrigerant R152a produces the lowest total equivalent warming parameter
compared with R22 and R290. The TEWI ofR290 and R152a are lower than that
ofR22 by 8.2 % and 30.03 %; respectively at a certain evaporator air velocity of
1.2 m/s and the evaporator air inlet temperature of 31 QC.
The study also showed the effectiveness of the upgraded instructional unit
which was designed and applied to the students of the third grade of refrigeration
and air conditioning technology in the faculty of industrial education. There was
a difference between the mean of the experimental group in the tribal and remote
measurements ofthe knowledge test at the level of 0.01
There is also a significant difference between the mean scores of the
experimental group in the tribal and remote measurements of the note card at the
level of 0.01.