Compressor Capacity Control

Compressor Capacity control of a refrigeration plant, also known as refrigeration compressor unloader valve, can be defined as a system which monitors and controls the output of the plant as per the load on demand. Similarly, the compressor shaft seal ensures the crankcase lube and the refrigerant does not leak out of the compressor from the shaft connected to the driving motor.
The efficiency of the reefer plant depends on its ability to keep different rooms or holds at a different temperature. Each room will have its own load demand hence the refrigeration plant’s output has to be controlled to achieve required cooling.
As the load (temperature) of one room is reached to its required temperature, there will be no more need of the refrigerant for cooling. Hence, the solenoid valve supplying refrigerant to that room will shut.
The simplest forms of controlling the room temperature are:
Using Variable Speed Motor (Normally used on small AC units)-
Controlling on-off cycling of the compressor
Using the Cylinder unloading method of keeping the suction valve in open position. This is accomplished by introducing a capacity controller valve in the compressor which is operated by lube oil pressure (hydraulic type) or by using a solenoid operated control valves
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[@thewallstreetjournal5675]

You got something 180 degrees backwards in your description. When the heating load of the plant increases. Crankcase pressure increases. and this should open the suction valve. To allow more pistons to push refrigerant. The reason loaders exist. Is to prevent short cycling of the compressor. When it is caused By increased heat of compression when the suction pressure of the refrigerant is to low. You don't unload pistons when the crankcase pressure gets to high. You use a CPR valve to limit the pressure to the compressor. During hot pull-downs (high heat loads).

[@hamidrezasheikhi8897]

amazing👍👌👏

[@ahmadtammimalbarra2676]

thanks for sharing, i want to ask you about the difference between pressure switch type unloader contorl and centrifugal type unloader control. thank you

[@cck0728]

Good video.... What is the relation of "crankcase pressure" with "unloading mechanism"? Thanks.

[@oktemgoncuoglu9107]

Crankcase pressure means suction pressure, when system load is high also means too much evaporation pressure which after this point gases goes to the compressor suction. In here i guess it is basically saying "when suction pressure is high, that means the system load is high, more coolant required, compressor should work to meet this demand".

[@cck0728]

Thanks for your kind reply... Thanks .​@@oktemgoncuoglu9107

[@muhammadrashidali8091]

Thanks for sharing such a great info, please let me know the difference between volume and capacity valave

[@madushaherath1000]

Good job

[@naageednaageed5927]

Hi deer can you explain how dose the piston loader in secrew compressor work ,thanks alot

[@marineinsight]

Will do soon

[@inammir1979]

As always informative....

[@marineinsight]

Hey Inam, Thank you for your comment. Please do share and support 👍🏻

[@ezhilkumar3818]

How to remove unloder valve . What is the procedure to remove . Because compressor app is fluctuating 20amp to 40amp 20 is constant but running full day with out cut off . What was the problem .

[@samsshuvo7197]

How the throughput of refrigerant for reciprocating type compressor is controlled

[@dailylifechallenge]

Nyc

[@marineinsight]

Thanks for liking

[@toyinorodare4072]

Thank you for this video

[@marineinsight]

Hey Toyin. Glad you liked it. Please check other refrigeration videos in this playlist - kzbin.info/aero/PL_mDuIImDS9Nhu6ERvcbYc6gMu_2OyyqM

[@raguramanr9882]

Could you please explain what is root cause of Refrigerant leak in the High pressure Relief valve for Air Cooled Chillers ???

[@marineinsight]

One of the most common issue is - leakage in the relief valve seat

[@raguramanr9882]

@@marineinsight Thanks for your reply. Is there is any specific reason for this relief valve seat leakage,(Like Non maintenance of Filter or Imbalancing of water flow or varour thermostat set point??)

[@satheeshansatheesh]

What is compressor load moter alam?

[@marineinsight]

The motor is being overloaded

[@toyinorodare4072]

thank you

[@marineinsight]

You're welcome

[@velkumarramaraj9576]

How solenoid valve operated in unloader mechanism?

[@marineinsight]

Solenoid function is pretty simple, instead of the oil supply operating the unloader valve (keeping the suction open), it is pushed by solenoid valve to open the suction valve whenever needed

[@vikashjha3003]

helpful

[@marineinsight]

Thank you Vikash. Please do share and support 👍🏻

[@MuhammadYousaf-xs4og]

full load compressor the lub pump go twon oil pressure and then compressor was trip this is the problem

[@nithiyanandhamsubbarayan3514]

What is capacity 33%,66%,100%how it is working on ship Ac please start from the very basic

[@ishuPandey03]

That means when the oil suppy to the unloader is stopped all of the units are working and when the oil will be supplied then all unloaders will work cutting off all cylinders?

[@marineinsight]

Yes. 👍🏻

[@marineinsight]

The oil supply to the unloader will depend on the crankcase pressure.

[@uci77]

Sir, i have problem with my compressor 5h40. Previosly compressor cut off caused LO pressure low, caused oil leaking from saat seal. After we top up oil and running the compressor, suction and oil pressure are normal but ampere reading low (40Amp), we tried to regulate clockwise the capacity control but compressor not respon, ampere not coming up also. Please your suggest Sir. Thankyou

[@altafgawande7553]

How I can exactly make a decision to discover that the system is under charged and need to charge refrigerant into system

[@marineinsight]

One or multiple reasons - www.marineinsight.com/refrigeration-air-conditioning/8-most-common-problems-found-in-ships-refrigeration-system/

[@AnkitKumar-uk1nr]

1st view again

[@marineinsight]

Awesome 👍🏻

[@papashangoable]

doesnt make sense kindly verify the video before uploading

[@rishirajsingh008]

Ha bhai ye dono case mein oil supply bnd krde raha hai...jbki load increase k case me hi sirf bnd rhega .