Water cooling is commonly used in air compressors. Intercooling not only reduces the work input but also reduces the compressor discharge temperature leading to better lubrication and longer compressor life.
Why is multistage compression used Mcq?
Why is multi-stage compression used? a) To improve C.O.P. Explanation: By expanding the refrigerant very close to the saturated liquid state refrigeration effect can be improved. And if the refrigerant is compressed very near to the saturated vapour line by using compression in more stages, overall work can be reduced.
Is used in multistage compression?
Multi-stage compressors feature a series of cylinders, each of a different diameter. Between each compression stage, the air passes through a heat exchanger, where it is cooled. Cooling the air reduces the amount of work necessary to compress it further.
What is multistage compression?
Multistage compression refers to the compression process completed in more than one stage i.e. a part of compression occurs in one cylinder ( L.P. cylinder) and subsequently compressed air is sent to subsequent cylinders ( H.P. cylinder) for further compression.
What is multistage compression system?
MULTISTAGE COMPRESSION: Multi staging is simply the compression of air or gas in two or more cylinders in place of a single cylinder compressor. … For isothermal compression and expansion process, the loss during compression is equivalent to the compression work, and no intercooler is required.
What is the use of multistage compression in a compression refrigeration system?
Advantages of multistage compression are:
This makes compressor lighter and cheaper. 4) Heat removal during condensation is reduced hence size of condenser is reduced. 5) Volumetric efficiency of compressor increases due to reduced pressure ratio in each stage. 6) Temperature at end of compression would be less.
Why are multistage compressors preferred?
For a given pressure ratio, the multistage arrangement improves volumetric efficiency. The lower temperature range in each stage of compression improves the lubrication. Pressure ratio per each stage is lowered and it reduces the leakage loss.
What is the use of multistage compressor in refrigeration system?
Advantages of multistage compression are:
This makes compressor lighter and cheaper. 4) Heat removal during condensation is reduced hence size of condenser is reduced. 5) Volumetric efficiency of compressor increases due to reduced pressure ratio in each stage. 6) Temperature at end of compression would be less.
Why is inter cooling done in multi-stage compression?
Ideally, the cooling process takes place at constant pressure, and the gas is cooled to the initial temperature T1 at each intercooler. Multistage compression with intercooling is especially attractive when gas is to be compressed to very high pressures.
What is the purpose of after cooler in multi cylinder compressor?
An Aftercooler is any mechanical device used to cool a fluid, including liquids or gasses, between stages of a multi-stage heating process, typically a Heat Exchangers that removes waste heat in a gas compressor.
Why inter coolers are required for multi-stage reciprocating compressors?
In multistage compressors, with each compression cycle, the pressure increases, which leads to an increase in temperature. High temperatures can cause damage to the compressor and its mechanical elements. Thus, it is essential to reduce the air temperature.
What is Mcq brine?
Solution(By Examveda Team)
Brine refers to water saturated or strongly impregnated with salt.
Is multistage compression with intercooling adopted?
12. Why is multistage compression with intercooling adopted? Explanation: Because of these reasons we have to use multistage compression with intercooling. Explanation: Here p1 is the evaporator pressure and p2 is the condenser pressure.
Which of the following is true for a multi-stage compression *?
Which of the following is true for a multi-stage compression? Explanation: These are few advantages of multi-stage compression. Explanation: Multi-cylinders need smaller flywheel and give uniform torque.
What is the purpose to use multi-stage air compressor in place of single stage?
Advantages: 1. Saving in work input: The air is cooled in an intercooler before entering the high pressure cylinder. Hence less power is required to drive a multistage compressor as compared to a single stage compressor for delivering same quantity of air at the same delivery pressure.
Which of the following is not an advantage of multistage compression with intercooler?
6. Which of the following is not a disadvantage of multiple compressions with intercooling between the stages? Explanation: The cylinder wall thickness of low pressure cylinder is reduced, since it is designed to withstand low pressure only. It reduces the cost of the compressor.
What are the advantages of multi staging of reciprocating compressor?
Advantages of multistage reciprocating air compressor: It improves the volumetric efficiency for the give pressure ratio. It reduces the leakage loss considerably. It provides effective lubrication because of lower temperature range.
Why a multi-stage compressor system reduces compressor power?
Compressing in multiple stages allows cooling to occur between the stages, which saves work in the compression process. Air compressor performance typically approximates isentropic compression, allowing an increase in the air temperature over the course of the compression process.
Why multi-stage or compound VCR with water intercooler and liquid sub cooler is used?
Why is multi-stage or compound VCR with water intercooler, liquid sub-cooler, and flash intercooler used? a) To improve C.O.P. Explanation: By de-superheating or intercooling the refrigerant before the second stage compression but not till the saturated vapor line, can decrease the total work required.
What are multi pressure systems?
16-1 Multipressure systems in industrial refrigeration A multipressure system is a refrigeration system that has two or more low-side pressures. The low-side pressure is the pressure of the refrigerant between the expansion valve and the intake of the compressor.
When water intercooling is used in multistage compression it reduces the work to be done in high pressure compressor?
Clarification: When water intercooling is used in a multi stage compression the work to be done in high pressure is reduced, the specific volume of the refrigerant is reduced and a compressor of less stroke volume is required. 6.
What is multi-stage centrifugal air compressor?
Larger air compressors, typically over 500 hp, in refineries, pulp and paper plants, chemical and other processing plants often have high-speed, multi-stage air compressors called “centrifugal” air compressors. … They compress air to plant pressure from atmospheric conditions, and deliver it to the dryer.
What type of multi-stage compressor is used on a gas turbine?
2 Compressor/expander. The general multistage compressor model may have several functions: polytrophic and isentropic compressor, positive displacement compressor, intercooler between stages, isentropic turbine.