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Condensers

FILL IN THE BLANKS REFRIGEATION CONDENSERS

https://www.mesubjects.net/wp-admin/post.php?post=7356&action=edit         Refrigeration Filling blanks Expansion valves

https://www.mesubjects.net/wp-admin/post.php?post=6742&action=edit        Q. A. Vapor Compression Refrigeration-3

https://www.mesubjects.net/wp-admin/post.php?post=6740&action=edit         Refrigeration Compressors

FILL IN THE BLANKS REFRIGEATION CONDENSERS

Fill in the blanks for condensers in refrigeration increase the understanding. Thus, more fill in the blanks on condensers be tried to further increase the knowledge.

  1. Condenser removes ——— and ——— heat.
  2.  Vapors change into liquid in the condenser at the  ———— temperature.
  3.   In the condenser, vapors change into liquid at a  ———temperature.
  4. During change of vapors into liquid in the condenser ———-remains constant.
  5. Air cooled condensers are used with ————— refrigeration plants.
  6. Water cooled condensers are used with ————–capacity refrigeration plants.
  7. Evaporation cooled condensers are used with —————capacity refrigeration plants.
  8. Hot water in the condenser is cooled by ———–for reusing in the condenser.
  9. Blower used for cooling in the cooling tower causes ——– draft.
  10. ———- pump is used to circulate water in the cooling tower.
  11. Receiver stores the ———pressure liquid refrigerant.
  12. The installation of the receiver is between the condenser and the————-cum filter.
  13. While refrigerant in the receiver is to be collected, its ——— valve is closed.
  14. A fine metallic ———– is used in the drier cum filter.
  15. ————- is filled in the drier cum filter for removing water from the—————.
  16. Drier cum filter removes —————–particles and————–.
  17. Drier cum filter can be refillable or —————— type.
  18. The location of the Drier cum filter is after the —————– in the refrigeration circuit.
  19. In refrigeration, receiver is used with —————capacity refrigeration unit.
  20. ————- cooled condensers are used in small refrigeration units.
  21.  Evaporating condenser uses  water and ——– for condensing the refrigerant.
  22.  Outlet of the drier cum filter is connected to the ————-device.
  23. Cooling towers have natural, forced and ———— type drafts.
  24. Use of cooling tower is necessary when the space is —————.
  25. One can use cooling pond i when the space is —————.
  26. There is ——- difference in the aim of the cooling tower and the cooling —————.

ANSWERS

  1. Super heat and latent heat, 2. Saturation, 3.constant, 4. Pressure, 5. Domestic units, 6.medium, 7. Large, 8. Cooling tower, 9. Forced, 10. Centrifugal, 11. High, 12. Drier, 13. Outlet, 14.sieve, 15. Silica gel, 16. Solid, moisture, 17. Replaceable, 18. Receiver, 19. Large, 20. Air, 21. Air, 22. Expansion, 23. Balanced, 24. Limited, 25. Unlimited, 26.no, pond


COOLING TOWERS-NATURAL AND FORCED DRAFT

COOLING TOWERS-NATURAL AND FORCED DRAFT 

Function

Cooling towers cool the hot water from the condenser so that same water can be reused time and again to reduce the cost of water used in condenser. Water is used in the condenser for condensing refrigerant for medium cooling plants having up to 100 tons of refrigeration cooling capacity. It is a  special type of heat exchanger. In this, hot water and atmospheric air are brought into direct physical contact. Air gets heated up and water gets cooled. Thus, some amount of water also gets evaporated and goes away with air. This evaporation is the main cause for the cooling of water. The cooling towers are one of main component of refrigeration units having water cooled condensers. Thus, these are used in  power plants, chemical processing industries and steel mills. Further, these are used to provide comfort cooling in hotels, hospitals and airports.

Types of Cooling Towers

There are four types of cooling towers mentioned below.

(i) Natural draft cooling tower–No blower is used.

(ii) Forced draft cooling tower – When a blower from below introduces air into the cooling tower.

(iii) Induced draft cooling tower – When a blower is placed at the top of the cooling tower and sucks air into it.

(iv) Balanced cooling tower – When induced and forced blowers are placed in the tower.

Out of these cooling towers, natural and forced cooling towers are more common in refrigeration and air conditioning.

 Advantages of a cooling tower

(i) There is a Significant reduction in the cost of water used in the condenser.

(ii) Compact – Does not need any extra space as it is mounted on the roof of a building or in the vertical orientation.

Difference between Natural Draft and Forced Draft Cooling Towers

Sr.No. Natural Draft Cooling Tower Forced Draft Cooling Tower
1. Hot water from condenser is cooled by natural air using free convection. Hot water from condenser is cooled by moving air using a blower.
2. It is widely open on sides. It is less open on sides.
3. It occupies more space. It occupies less space and hence is compact.
4. It is less efficient. It is more efficient.
5. It is cheap. It is costly.
6. It is installed in the open space where natural air is freely available. It is installed at the roof of the building.
7. Used for less refrigeration requirements. Used for large refrigeration requirements.


MCQ-CONDENSERS AND EVAPORATORS

MCQ-CONDENSERS AND EVAPORATORS 

Dry evaporators are used in domestic units. These ensure that only super heated vapor goes to the compressor for its safety. Flooded evaporators are in commercial and industrial applications, These improve the COP of the plant.
 

 Evaporators

 Dry evaporator is used in A.C. Units of capacity
(a) < 3 tons
(b) < 10 tons
(c) >10 tons
(d) None
(Ans:a)

Flooded evaporator is used in A.C. Units of capacity
(a) < 3 tons
(b) < 10 tons
(c) >10 tons
(d) None

(Ans:c)

In a dry evaporator, refrigerant at the outlet is

(a) in the wet state

(b) saturated state

(c) super heated state

(d) None

(Ans: c)

In a flooded evaporator, refrigerant at the outlet is

(a) in the wet state

(b) saturated state

(c) super heated state

(d) None

(Ans: a)

Flooded evaporator needs at the outlet a

(a) Flash chamber

(b) Accumulator

(c) Inter cooler

(d) None

(Ans: b)

Finned tube evaporators are used in a

(a) Fridge

(b) Window air conditioner

(c) Water cooler

(d) None

(Ans: b)

Bare tube evaporator is used in a
(a) Cold storage plant

(b) ice plant

(c) milk Plant

(d) None

(Ans:b)

Evaporator in a refrigeration plant is fitted

(a) Before the condenser

(B) After the condenser

(c) After the compressor

(d) None

(Ans: d)

Evaporator in a refrigeration plant is fitted

(a) Before the condenser

(B) Before the expansion valve

(c) Before the compressor

(d) None

(Ans: c)

Condenser in a real refrigeration system does
(a) De-super heating and condensation
(b) Sub-cooling and condensation only
(c) De-super heating, condensation and sub-cooling
(d) None
(Ans:c)

Condenser in a refrigeration system decreases
(a) Temperature only
(b) Pressure only
(c) Temperature and pressure
(d) None
(Ans:a)

Condenser is air cooled when tons of refrigeration required is
(a) < 3
(b) <50
(c) > 100
(d) None
(Ans:a)

Condenser is water cooled when tons of refrigeration required is
(a) < 3
(b) <50
(c) > 100
(d) None
(Ans:b)

Which is the type of condenser used for ≤ 3 Tons cooling capacity of a refrigeration unit?
(a) Shell and tube type
(b) Finned tube type
(c) Bare tube type
(d) None
(Ans:b)

Which is the type of condenser used for 10- 50 Tons cooling capacity of a refrigeration unit?
(a) Shell and tube type
(b) Finned tube type
(c) Bare tube type
(d) None
(Ans:a)

Which is the type of condenser used for ≤ 3 Tons cooling capacity of a refrigeration unit?
(a) Water cooled
(b) Air cooled
(c) Water and air cooled
(d) None
(Ans:b)

Which is the type of condenser used for ≥ 3 ≤50 Tons cooling capacity of a refrigeration unit?
(a) Water cooled
(b) Air cooled
(c) Water and air cooled
(d) None
(Ans:a)

Which is the type of condenser used for > 50 Tons cooling capacity of a refrigeration unit?
(a) Water cooled
(b) Air cooled
(c) Water and air cooled
(d) None
(Ans:c)
Forced air cooled condenser in refrigeration unit has a
(a) Counter flow
(b) Parallel flow
(c) Cross flow
(d) None
(Ans:c)

Water cooled condenser in refrigeration unit has a
Counter flow
Parallel flow
Cross flow
None
(Ans:a)

Heat lost in the condenser is

(a) <(N+W)

(b) = (N+W)

(c) >(N+W)

(d) None

(Ans:b)

Heat lost in the condenser is due 

(a) Decrease in the degree of super heat

(b) Decrease in the degree of sub cooling

(c) Decrease in degree of super heat +Latent heat + Increase of degree of sub-cooling

(d) None

(Ans: c)




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