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HỘI THẢO QUỐC TẾ ATiGB LẦN THỨ CHÍN - The 9 ATiGB 2024 27

develop an energy management system for reduction With W is weight (kg); H is height (m)
of energy consumption of the air conditioning system
[10].  is the person's heat dissipation coefficient,
h
The Heat Balance Method (HBM) was used by depending on the activity level of the person in the
Paul and Rajakumar to estimate the heating and cabin. According to experiments, the heat dissipation
cooling loads applying to the vehicle cabin. The coefficient values of the driver and passenger are 85
2
results was that the thermal load of automobile air W/m and 55 W/m , respectively [14].
2
conditioning system was calculated, which became a 3) The Radiation Heat
basic for design and improving the energy
consumption of the automobile air conditioning Radiation heat is generated by solar radiation
system [11]. through the car‘s windshield. It depends on many
factors such as weather, clouds, air humidity, radiation
The objective of the study was: i) to determine the
mathematic equations of calculating the thermal loads direction and angle. However, for simplicity in
and cooling capacity of a vehicle air conditioning calculation, it was assumed that the radiation heat was
system; ii) to simulink the thermal loads applied to the uniform for the entire windshield surface area, and
vehicle cabin. The results of the study would determined according to the equation below [15].
effectively support the design and improving the Q = . . R  (4)
F
cooling capacity and operating efficiency of air rad k k
conditioning system.
2
F is the windshield surface area (m ); R = 408
2. METHODOLOGY OF RESEARCH k
W/m is the solar radiation coefficient [15];  = 0.92
2
A. Researching Subject k
is the glass factor, depending on the color and type of
The calculation and simulation for thermal loads
were carried out to determine the cooling capacity of a glass [15].
small size family car’s air conditioning system. 4) The Heat Exchanged with the Air
B. Calculation of Thermal Loads of the Vehicle The air outside the cabin (environment air) has a
Air Conditioning System significant influence on the heat in the cabin. This
effect is through convective heat exchange between
1) The Total Heat Applied to Cabin
the air and the windshield and body shell. The heat
The total heat value calculated for the cabin would exchanged with the air was determined according to
include many different types of heat that affect the the equation below [13].
cabin. The total heat was determined according to
=
equation below [6]. Q F . h ( . t − t ) (5)
amb cabin cabin kk in
Q = Q + Q + Q
total hum rad amb (1) 1 1 1  i
+
Q + Q + Q = + +  ()
eng exh ven h h h k
cabin kk in i
In which, Qtotal, Qhum, Qrad, Qamb, Qeng, Qexh, Qven
+
were the total heat, heat emitted from humans, h = 0.6 0.64 V ()
radiation heat, heat exchanged with the air, heat
emitted from the engine, heat emitted from the exhaust F cabin is the total contact area of the windshield and
gas and heat loss due to ventilation between cabin and body shell (m ); t and t are the ambient air
2
environment. kk in
o
temperature and cabin temperature ( C);
2) The Heat Emitted from Humans
Human activities would generate heat and moisture h cabin is the equivalent heat exchange coefficient
2 o
(sweat). This amount of heat increases the air (W/m . C), and determined according to the following
temperature in the cabin. The heat emitted from below [13].
human was calculated using the equation below [6]
1 1 1  i
Q =  A . (2) = + +  (8)
hum h h h h h k
cabin kk in i
In which, A was the relative heat dissipation area hkk và hin are the convective heat exchange
h
of a person, and determined as a function of the coefficients of the air outside and inside the cabin,
2
person's height and weight [14]. respectively (W/m ). They were determined according
to the following empirical equation [13].
A 0.202.W= 0.425 . H 0.725 (3)
h
h 0.6 0.64 V= + (9)
ISBN: 978-604-80-9779-0