January 17, 2024
PHYSICS 2 LEC
Passive Cooling
COOLING & REFRIGERATION
Ambient Temperature


Temperature of the environment
The air temperature of any object or
environment where equipment is stored.
(2) TYPES OF COOLING
Active Cooling








External power source
Forcing air
Fan=needs external power
HSF
Smaller
Noisy because of fan
An active cooling system uses energy to cool
the house.
Some examples of active cooling systems
include fans, evaporative air conditioners,
and refrigerative air conditioners such as
'split systems' and these systems consume
varying amounts of energy, water and
money.





Cool air to hot air
Larger
Quiet operation since there is no fan
Passive cooling uses free, renewable
sources of energy such as the sun and wind
to provide cooling, ventilation and lighting
needs for a household.
This additionally removes the need to use
mechanical cooling.
January 17, 2024
PHYSICS 2 LEC
Advantages and disadvantages of electronics
devices is called TRADE OFF
Evaporative Cooler


By passing outdoor air over water-saturated
pads, the water in the pads evaporate,
reducing the air temperature by 15°- to 40°Fbefore it is directed into the home.
When operating an evaporative cooler,
windows are partially opened to allow warm
indoor air to escape as it is replaced by
cooler air.
Evaporative Cooling system

Evaporative cooling, otherwise known as
adiabatic cooling, works on the principle of
water evaporation through which the air is
cooled down to a comfortable temperature.
 Disadvantages of Evaporative
cooling system
a. does not perform well in
humid climates or during rainy
periods.
b. temperature control is limited.
c. basic air filter system only,
many airborne irritants or
odors missed.
d. not ideal for those with
asthma or respiratory issues.
e. can use up to 25 liters of
water* an hour depending on
the fan speed and humidity.
MNEMONICS
Duplexer



Used for radar
an electronic device that allows bi-directional
(duplex) communication over a single path.
In radar and radio communications systems,
it isolates the receiver from the transmitter
while permitting them to share a common
antenna. Most radio repeater systems
include a duplexer.
January 17, 2024


Diplexer





Separates signals
Transmits two signals
A diplexer separates signals based on
frequency.
allows two different devices to share a
common communications channel.
enables the sharing of a common antenna
between two distinct frequency bands.
PHYSICS 2 LEC
A diplexer separates signals based on
frequency, whereas a duplexer separates the
transmit and receive path of signals based on
direction.
a ""Duplexer"" means the separation function
of transmission and reception and the
""Diplexer"" means the band switching
function of multi-band respectively.