RECIPROCATING COMPRESSORS Presented By, ALFAS REHMAN P.A

CONTENTS Introduction Reciprocating compressor Working principle Thermodynamic cycle Classification Major components Single and Multi stage compressors Intercoolers Grasso Piston compressors AC series compressors RC series compressors V series compressors Packaged air compressor Applications Advantages Disadvantages

INTRODUCTION Refrigeration is one of the emerging field in the industrial segments, and it significantly influence us in our day to day life. Compressor is the heart of a refrigeration system. A compressor is a mechanical device that increases the pressure of working fluid by reducing its volume here refrigerant is the working fluid. Reciprocating Compressors are one of the most widely used types of compressors for refrigeration and air conditioning applications.

RECIPROCATING COMPRESSOR Reciprocating compressor is a machine which is used to increase the pressure energy of the working fluid by means of piston cylinder arrangement, here in refrigeration the working fluid is refrigerant. It is a positive displacement compressor that uses pistons driven by a crankshafts to deliver gases at high pressure.

WORKING PRINCIPLE The reciprocating compressors comprise of the piston and the cylinder arrangement similar to the automotive engine. While the engine generates power after consuming fuel, the reciprocating compressor consumes electricity to compress the refrigerant. Inside the cylinder the piston performs reciprocating motion which enables the compression of refrigerant inside it.

THERMODYNAMIC CYCLE Clearance volume is the space remaining in the compressor cylinder at the end of the stroke. At the completion of each compression stroke, the compressed gas trapped in the clearance space expands against the piston and adds to the force of the return stroke. Expansion of the gas trapped in the clearance space occurs before the suction valve opens to admit new gas into the cylinder. As a result, part of the piston displacement occurs before the suction valve opens. The compression process in reciprocating compressors is nearly isentropic.

CLASSIFICATION According to alignment of cylinder Horizontal , Vertical , Inclined and V type. According to number of stages Single and multiple According to design Open type and Hermetic type According to number of cylinders Single cylinder and Multiple cylinders According to pressure Low pressure compressors and High pressure compressors According to lubrication Lubricated type and Non lubricated type According to action Single acting and Double acting

MAJOR COMPONENTS Piston and cylinder Crank shaft Connecting rod Suction and Discharge valves

Single and multi stage compressors In a single stage reciprocating compressor it is not practical to produce compressed fluid at high pressure. Compressor performance typically approximates isentropic compression, allowing an increase in the gas temperature over the course of the compression process. In a two-stage compressor, air is partially compressed using isentropic compression, and then cooled in a heat exchanger, called an intercooler. We can see that there is a distinct efficiency advantage to multiple stages when intercoolers are used.

INTERCOOLERS An intercooler is any mechanical device used to cool a fluid, including liquids or gases, between stages of a multi-stage heating process, typically a heat exchanger that removes waste heat in a gas compressor. They are used in many applications, including compressors, air conditioners, refrigerators, and gas turbines.

GRASSO PISTON COMPRESSORS GEA Grasso have manufactured a 3 series of reciprocating compressors so far. They are introduced based on the chronological order. AC series compressors RC series compressors V series compressors

1.AC series compressors The AC series are open compressors. Here I am talking about AC 80R model in order to get a basic idea about its classification. The model AC80R consists of 8 types with 4,5,6,7,8,10,12 and 16 respectively.

2.RC series compressors RC series RC9 RC10 RC11 RC12 RC12E Here I am talking about RC9 model. The range of RC9 compressors includes 3-single-stage and 2 two-stage compressor types.

3.V SERIES COMPRESSORS KEY FEATURES GEA Grasso has officially launched its Vseries compressors to market in 2008.With the GEA Grasso V series compressor series , Grasso starts a complete new era in the refrigeration market. The modern GEA Grasso V series is a piston compressor that features a maintenance monitor that shows upcoming service intervals. KEY FEATURES Unique steel welded compressor housing. Maintenance monitoring facility Suitable for speed control Low noise level Low Total Cost of Ownership

PACKAGED REFRIGERATION COMPRESSOR A GEA Grasso compressor component included in the V series lubricated type direct drive execution which ranges from 150 to 900 kW. Type: Refrigerant Technology: piston Lubrication: lubricated Portability: stationary Other characteristics: direct-drive Power: Min.: 150 kW (201.15 hp) Max.: 900 kW (1206.92 hp)

APPLICATIONS Marine Supermarkets Process cooling Railway Commercial travelling Ice rinks Fishing and food industries Air conditioning Transport refrigeration Cleanroom technology

ADVANTAGES Reciprocating compressors are cheaper, it costs about half the rotary compressors. Low installation and service cost as it have low maintenance points. Ideal for light use - For smaller jobs, reciprocating air compressors are more efficient and more affordable. If you need a compressor for your home workshop, this is the way to go. Durable - Reciprocating air compressors tend to be very sturdy and reliable. They are able to withstand harsh environments.

DISADVANTAGES Heavy foundation. Pulsating flow. Low reliability. High maintenance. Torsional imbalance. Noisy operation. High wear and tear. High oil carry over (greater than 10 ppm).

CONCLUSION Refrigeration is one of the emerging segment in the industrial as well as commercial segment. Compressors are the heart of a refrigeration system. Reciprocating compressors are still the most common choice for many small compressed air system users. For many of these applications , the relatively low demand and quality needed make the piston a cost effective choice. Because of their higher efficiency, low initial cost and maintenance cost it is being successfully used in small scale applications.

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