Presentation about refrigeration condenser types and function

1. 28 / 2 / 2023
condenser air conditioning and
refrigeration

2. 2
‫االسماء‬
:
.1
‫ابوسريع‬ ‫سيد‬ ‫احمد‬ ‫عبدهللا‬
.2
‫ابوسريع‬ ‫سيد‬ ‫احمد‬ ‫عبدالرحمن‬
.3
‫عبدالوهاب‬ ‫عادل‬ ‫عمرو‬
.4
‫عبدالمنعم‬ ‫وجيه‬ ‫عالء‬
.5
‫هللا‬ ‫ضيف‬ ‫ياسر‬ ‫محمد‬
.6
‫كامل‬ ‫محمد‬ ‫محمود‬ ‫عبدهللا‬
.7
‫حسن‬ ‫عادل‬ ‫مصطفي‬
Presented to /
Dr. / Amr kaoud
air conditioning air
conditioning and refrigeration

3. 3
CONTENT
introduction
Condenser function
Typical condenser problems
Governing equation
Condenser choosing
Types of condensers
Problem on condenser
Design of condenser
Introduction
I
II
III
IV
VI
V
VII
VIII

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5. 5
 Ideal vapor compression refrigeration cycle :
1. isentropic compression in compressor.
2. constant pressure heat rejection in condenser.
3. Throttling in an expansion device.
4. constant pressure heat absorption in evaporator.
 Main components Refrigeration system :
Introduction
 condenser
 Expansion device
 evaporator
 compressor

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Introduction
The condenser or condenser coil is one of two types of
heat exchangers used in a basic refrigeration loop. This
component is supplied with high-temperature, high-
pressure vaporized refrigerant coming of the compressor.
The condenser removes heat from the hot refrigerant
vapor until it condenses into a saturated liquid state. The
process called condensation.

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Function of condenser
 To remove the heat from
the hot refrigerant
vapors
1  Cooling
1
 Condense them into
liquid refrigerant. 3

8. 8

9. 9
 blocked airflow.
 condenser fan not working.
 refrigerant leakage in condenser coils.
Typical problems of condenser :
 scaling and fouling in condenser tubes.

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Typical problems of condenser :
 Blocked airflow :
 In order to work properly, the condenser unit must have room to
breathe.
 by the time, layers of dusts will block the airflow and make it more
difficult for your unit to blow the right amount of air over the coils
 condenser fan not working
 condensers in common cases are located outside the building so
any thrown rocks, leaves or sticks can damage the fan.
 dust accumulation causes un balanced motion that affects the
amount of air flow and reduces the efficiency

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Typical problems of condenser
 Refrigerant leakage:
 If the line between condenser and evaporator has a leak, the process
cannot be carried out effectively and puts the entire system in danger
 Refrigerant leaks can also occur along the condenser coil or at the
connection to the compressor.
 Fouling and scaling:
 Over time, the dirt and debris that is blown around your condenser unit
can build up both inside and out.
 these particles can develop a layer that will act as insulation on the
coils.

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How to avoid condenser unit problems:
Typical problems of condenser
 Replace dirty air filters :
 Airflow problems that lead to coils freezing are often caused by clogged air filters.
 Install programmable thermostat :
 Eliminate issues with older control systems by installing new thermostats
 You can even get thermostats that can be controlled remotely using your smartphone or tablet
 Clean the around area of the outdoor unit :
 Don’t neglect annual maintenance
 Virtually all of the most common causes of air conditioner problems can be easily prevented with regular maintenance.

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14.  Choosing the Right Refrigeration Condenser :
Location Condenser size
Forced draft vs.
induced draft
Coil charge

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 Air-cooled condenser
:
 Natural Convection
 Forced Convection
 Water-cooled condenser :
 Double Tube
 Shell and Coil Condenser
 Shell and Tube Condenser
 Air-cooled condenser
:
 Re-cooled LC
Types of condenser

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Water cooled
Air cooled
Condenser type
complex
simple
construction
Water not available every
where
Air is always available
availability
High cost
Low cost
Maintenance cost
complex
simple
Design consideration
Higher
lower
Exchange coefficient
high
low
Heat transfer
Comparison

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 Evaporative is often cheaper compared to water-cooled requiring a cooling
tower.
 Evaporative is used in places where we usually encounter a water supply
shortage.
 Evaporative is kept outside, so in cold seasons, the water pump is switched off so
as to prevent freezing water.
 Evaporator condenser

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types of condenser
 The condenser is classified into two types according to the cooling
working fluid based on the quantity of heat exchange :
 Water cooled condensers :
 A Water-Cooled Condenser is a heat exchanger that removes heat from
refrigerant vapour and transfers it to the water running through it.
 Capacity range is ( 2 – 500 ) T.R
 Air cooled condenser :
 An air cooled condenser (ACC) is a direct dry cooling system where steam is
condensed inside air-cooled finned tubes.
 Capacity range is ( 20 – 120 ) T.R

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types of condenser
 water cooled condenser :
 working principal :
 This type of condenser is developed to transfer heat
from a working fluid to a secondary fluid.
I. The vapor normally enters the condenser at a temperature above
that of the secondary fluid.
II.When the vapor cools, it reaches the saturation temperature -
condensed into liquid - and releases large quantities of latent heat
III. quantity of vapor decreases and the quantity of liquid increases
IV.There will only remain liquid at the outlet of the condenser.
V. Heated water is taken for other purposes.

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 Advantages of water cooled condenser:
 There is thermal energy recovery to be used in other heating processes.
 This type of condenser can be housed indoors.
 A water-cooled system typically lasts years longer.
 It has higher heat transfer rate.
 Length of the condenser pipe is reduced which decreases the compressor work and thus
increases its efficiency.
 Disadvantages of water cooled condenser:
 Using water as a cooling medium might cause corrosion problem.
 Use of water as a cooling medium may result in the formation of scales in the supply line.
 Because of shortages of fresh water around the world, few countries can afford to run
water to waste.
 Using water tank makes the system bulky which results in problem during domestic use.
types of condenser

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types of condenser
 air cooled condenser :
 working principal :
 Refrigerant flows inside the tubes or coils and air flows over the external
surface of condenser tubes.
I. Atmospheric air comes in contact with the warm condenser tubes and
absorbs heat from the refrigerant.
II. At the same time, the large axial-flow fans intake air and sweep over
the tube bundles externally to carry away heat.
III. In tube bundles, the exhaust steam gradually changes to
condensates and is accumulated in the condensate tank through the
bottom headers. Moreover, the vacuum of the whole Air cooled
condenser (ACC) covers by the air evacuation system.

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 Advantages of air-cooled condenser:
 Air cooled condensers are simple in operation. They are smaller in size.
 Required maintenance of air cooled condensers is low.
 Design of air cooled condensers are less complex.
 This type of condensers is more flexible to use.
 installation cost is comparatively less.
 Cleaning process is easy.
 Disadvantages of air-cooled condenser:
 Air cooled condensers required more power to run.
 It is not suitable for long duration period.
 The cooling effect is not so high.
 It does not supply the required cooling in a short time.
types of condenser

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types of condenser
 Condenser Types According to Design :
 Tube-within-a-tube condenser.
 Shell and coil condenser.
 Shell and tube condenser.
 Air finned condenser.
Tube-within-a-tube condenser. Shell and coil condenser.
Shell and tube condenser. Air finned condenser.

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types of condenser
 Condenser Types According to Design :
Tube-within-a-tube condenser
 A tube-within-a-tube condenser is constructed by sliding one tube through
another tube.
 Heat from the discharge gas causes minerals to come out of solution Form
scale that adheres to the pipes.
 The scale acts as an insulator and reduces the rate of heat transfer.
 Capacity range is ( 2 – 500 ) T.R

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types of condenser
 Condenser Types According to Design :
Shell and coil condense
 Coil of tubing enclosed in a welded shell Water flows through the coil
Refrigerant from the compressor is discharged into the shell.
 The shell also acts as the receiver When refrigerant comes in contact with the
cool coil.
 It condenses and falls to the bottom This condenser must be
cleaned chemically..
 Capacity range is below ( 50 )T.R

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types of condenser
 Condenser Types According to Design :
Shell and tube condenser
 In this type of condenser number of straight water tubes are enclosed a large
cylindrical shell.
 The common materials for shell are steel and copper, In ammonia refrigerating
system steel tube is used because ammonia corrodes the copper.
 The water tubes are extended to the groove of tube sheet to achieve vapor tight
fit. Removable water boxes are bolted to the tube sheet.
 This arrangement facilitates cleaning of condenser in case of fouling.
 The hot refrigerant enters the shell at top. Refrigerant reject heat to the water
when it contacts with water tubes. Finally, the condensed refrigerant drops to
the bottom of shell.
 Capacity range is ( 2 – 200 ) T.R

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types of condenser
 Condenser Types According to Design :
Air finned condenser
 Air-cooled Heat Exchangers or Air Fin Coolers (or) Fin fan Cooler are the same
Air Cooling equipment.
 The Air Fin Coolers are basically designed with several rows of finned tubes in
a series of exterior and required numbers of fans.
 Fans are used to move the low temperature atmospheric ambient air over the
finned tube coil surface in order to cool the hotter fluid media.
 Capacity range is ( 20 – 120 ) T.R

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30. 30
In line cross flow condenser
 Design of an air cooled refrigerant condenser :
 Specifications:
Q = 125 Kw
Cooling load (heat duty)
R-134a condensing inside
tubes
Ts = 37 𝐶°
= 310 K
Refrigerant
Air
Inlet temperature, Ti=18𝐶°
Outlet temperature, To=26𝐶°
Mean pressure P=2atm
Coolant
To be selected
Heat transfer matrix
 Required :
Which material will fulfill the Q=125KW (Copper or wrought steel)

31. 31
Calculations:
 Properties of air :
At P = 2 atm and 𝑇𝑚 =
26+18
2
= 22 𝐶°
• 𝜌 = 2.32 Kg/𝑚3
• µ = 1.84× 10−6 Kg/m.s
• Cp = 1010 j/Kg.K
• K = 0.0259 W/m.K
• 𝑃𝑟 = 0.715
• 𝜈 = 7.69874 × 10−6𝑚2/𝑠
∴ Mass flow rate :
Q = ṁ Cp ( 𝑇𝑂 - 𝑇𝐼 )
∴ ṁ𝒂𝒊𝒓=
125
1.010 × 8
= 15.47 Kg/s
 properties of refrigerant ( R – 134a ) :
At P = 938 Kpa = 9.38 bar and T = 37 ℃
• ℎ𝑓𝑔 = 1661 KJ/Kg
∴ Mass flow rate :
Q = ṁ ℎ𝑓𝑔
∴ ṁ = 125
1661 = 0.075 𝐾𝑔/𝑠

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 Calculations :
 material of tubes : copper
 Inside Cross sectional area :
𝐴𝑆 =
Ԥ
4
(𝐷)2
= 0.00009369 𝑚2
 Inline cross flow condenser ( considered )
 Total number of pipes :
N = NT × NL = 105
 Mass flow rate of R-134a :
ṁ = P𝑅 𝐴𝑐 𝑉𝑅 ∴ 𝑉𝑅 = 1.66 m/s
 To match the economic velocity The range
should be between ( 1.37 to 2.9 ) m/s
 Total surface area of tubes :
𝐴𝑆 = π × 𝑂𝐷 × 𝑁 × 𝐿 = 12.57 𝑚2
 Mass flow rate of air
ṁ𝑎𝑖𝑟 = ρ × 𝑉
𝑎 × 𝑁𝑡 × 𝐿 × 𝑆𝑡
∴ 𝑉
𝑎= 9.854 m/s
 Maximum velocity for inline rows,
𝑉
𝑚𝑎𝑥= 𝑉
𝑎 ×
𝑆𝑇
𝑆𝑇−𝑂𝐷
= 75.71 m/s

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 Calculations.(cont) :
 Maximum Reynolds number :
𝑅𝑒 𝑚𝑎𝑥 =
𝑂𝐷∗𝑉𝑚𝑎𝑥
𝑣
= 124885.02
 Nusselt number :
𝑁𝑢𝑚 = 𝐶1 ∗ 𝑅𝑒
𝑚
∗ 𝑃𝑟
0.36 𝑃𝑟
𝑃𝑟(𝑤𝑎𝑡𝑒𝑟)
𝑛
= 0.27*124885.020.62
∗ 0.7150.36
∗
0.715
7.15
0.4
= 345.74
𝐿 = 𝐷ℎ =
𝑅𝑒 𝑚𝑎𝑥∗𝑣
𝑉𝑚𝑎𝑥
=
124885.02×7.69874∗10−6
75.71
= 0.012698m
𝑁𝑢𝑚
=
ℎ𝑚∗𝑙
𝐾
=705.93 W/𝑚2
. 𝐾
 Maximum overall heat transfer coefficient,
U=ℎ𝑚 = 705.093W/𝑚2
. 𝐾
 Log mean temperature difference :
∆𝑇1 = Ts – Ti = 37 – 18 = 19𝐶°
∆𝑇2 = Ts - To = 37 - 26 = 11𝐶°
LMTD =
∆𝑇1 − ∆𝑇2
𝐿𝑛(
∆𝑇1
∆𝑇2
)
=
19 − 11
𝐿𝑛(
19
11
)
= 14.64𝐶°
𝑄𝑚𝑎𝑥 = 𝑈 × 𝐴𝑠 × 𝐿𝑀𝑇𝐷
= 705.093 × 14.64 × 12.57
= 129.755 KW > 125 𝐾𝑊
So, achieved heat duty is greater than the
required one

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 from comparison :
1. Both material fulfill the required heat duty
2. It can seen that copper provides higher overall heat transfer coefficient with less amount of area
So, copper pipe was considered for the design of the condenser.
Heat duty,
Q (kw)
Maximum overall heat
transfer coefficient
W/𝑚2. 𝐾
Total surface area
subject
material
129.734
705.093
12.568
Copper 3/8
135.36
639.35
14.46
Wrought steel 1/4
comparison

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37. 37
comparison
 Heat balance equations:
Heat rejected from refrigrant = heat added to the cooling
water = heat transferred between refrigrant and water
𝑄𝑠𝑡𝑒𝑎𝑚 = 𝑄𝐻𝑇 = 𝑄𝑐𝑤
 Heat rejected from refrigrant :
𝑄𝑟𝑒𝑓 = 𝑚𝑟𝑒𝑓 ℎ𝑟𝑖 − ℎ𝑐𝑜𝑛𝑑
 heat added to the cooling water :
𝑄𝑐𝑤 = 𝑚𝑐𝑤𝐶𝑃𝐶𝑊 𝑡𝑐𝑤𝑜 − 𝑡𝑐𝑤𝑖
 heat transferred between refrigrant and water :
𝑄𝐻𝑇 = 𝑈𝐴𝑐𝑜𝑛𝑑∆𝑡𝐿𝑚
 𝑈 = Overall heat transfer coefficent
 𝐴𝑐𝑜𝑛𝑑 = Area of the condenser
 ∆𝑡𝐿𝑚= logartmic mean temprture difference
 logartmic mean temprture difference
∆𝑡𝑙𝑚=
∆𝑇𝐿𝑚𝑖 − ∆𝑇𝐿𝑚𝑜
𝐿𝑛
∆𝑇𝐿𝑚𝑖
∆𝑇𝐿𝑚𝑜
∆𝑇𝐿𝑚𝑖= 𝑡𝑠𝑎𝑡 − 𝑡𝑐𝑤𝑖
∆𝑇𝐿𝑚𝑜= 𝑡𝑠𝑎𝑡 − 𝑡𝑐𝑤𝑜
 condenser efficiency :
𝑐𝑜𝑛𝑑𝑒𝑛𝑠𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 =
𝑡𝑐𝑤𝑜 − 𝑡𝑐𝑤𝑖
𝑡𝑠𝑎𝑡 − 𝑡𝑐𝑤𝑖

38. 38
Solution:
 From steam table at (35℃ )
∴ P = 0.0562 bar
 As 1 𝑏𝑎𝑟 = 75 𝑐𝑚 𝑜𝑓 𝐻𝑔
∴ 𝑃𝑠𝑡𝑒𝑎𝑚 = 4.2 𝑐𝑚 𝑜𝑓 𝐻𝑔
𝑃𝑎𝑏𝑠 = 𝑃𝑎𝑡𝑚 − 𝑃𝑣𝑎𝑐𝑢𝑢𝑚
𝑃𝑎𝑏𝑠 = 76.3 − 70.1 = 6.2 𝑐𝑚 𝑜𝑓 𝐻𝑔 = 0.08267 𝑏𝑎𝑟
∵ 𝑃𝑎𝑏𝑠 = 𝑃𝑠𝑡𝑒𝑎𝑚 + 𝑃𝑎𝑖𝑟
∵ 𝑃𝑎𝑖𝑟 = 𝑃𝑎𝑏𝑠 − 𝑃𝑠𝑡𝑒𝑎𝑚
∴ 𝑃𝑎𝑖𝑟 = 0.08267 − 0.0562 = 0.02647 𝑏𝑎𝑟
1. Amount of air present :
 From ideal gas equation : P V = 𝑚𝑎 R T
∴ 𝑚𝑎 =
0.02647 × 105
× 1
287 × 308
= 0.02994 𝐾𝑔

39. 39
2. State of steam inters the condenser :
ℎ𝑓𝑔
At p = 0.082 2402.2
p = 0.08267 X
p = 0.084 2401
0.084 −0.08267
0.084 −0.082
=
2401 −𝑋
2401 −2402.2
∴ 𝑋 = 2401.798 𝐾𝐽/𝐾𝑔
 from steam table at 𝑇ℎ𝑜𝑡 𝑤𝑎𝑡𝑒𝑟 = 29 ℃
∴ ℎℎ𝑜𝑡 𝑤𝑎𝑡𝑒𝑟 = 121.5 KJ / Kg
 heat balance on condenser :
ms hf + xhfg − hh = mcw × Cpw × Tcw O − Tcw in
∴ 1188 × 176.4594 + 𝑥 2401.798 − 121.56
= 46270 × 4.18 × 31.15 − 16.75
∴ x = 0.9535
3. Vacuum efficiency :
𝜂 =
𝐴𝑐𝑡𝑢𝑎𝑙 𝑣𝑎𝑐𝑢𝑢𝑚
𝑃𝑎𝑡𝑚− 𝑃𝑠𝑡𝑒𝑎𝑚
=
70.1
76.3 −4.2
× 100 = 0.9722
∴ 𝜂 = 97.22 %

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 Refrencses
 https://spurkhvac.com/common-condenser-problems-
and-how-to-avoid-them/

41. 41
Thank you