Compressor Group 2 PDF

CHAPTER 4 COMPRESSOR GROUP 2  Our Group Members ABRIS AMARIS ANTARAN ASUNCION CANALE CLAR CORPUZ  Our Group Members DIAZ DE RIVERA ESCARILLA EVANGELISTA GUIÑEZ MATEO NAVARRO...

CHAPTER 4 COMPRESSOR GROUP 2  Our Group Members ABRIS AMARIS ANTARAN ASUNCION CANALE CLAR CORPUZ  Our Group Members DIAZ DE RIVERA ESCARILLA EVANGELISTA GUIÑEZ MATEO NAVARRO OLIVEROS PARENTA  Our Group Members SANDIG SANTIAGO TENORIO TEPACE WHAT IS COMPRESSOR? COMPRESSOR The compressor, often considered the "heart" of the refrigeration system, plays a crucial role in driving the refrigerant through the entire cycle. Its primary function is to compress the low-pressure, low-temperature refrigerant gas from the evaporator, transforming it into a high-pressure, high-temperature gas. This increase in pressure and temperature allows the refrigerant to release heat more efficiently in the condenser, facilitating the completion of the refrigeration cycle and enabling effective heat absorption (cooling) and heat rejection. fuNction of the compressor The compressor drives the refrigerant through the refrigeration cycle, increases its pressure and temperature from the evaporator, and releases heat in the condenser to maintain the desired cooling within the system.  COMPRESSion RATIO Measures how much the compressor increases the refrigerant pressure from the low side (evaporator) to the high side (condenser). FORMULA: High-Side Pressure (psia) Compression Ratio = Low-Side Pressure (psia) NOTE: Add 14.7 to gauge pressure (psig) to get absolute pressure (psia).  COMPRESSion RATIO WHY IT MATTERS: 1. Ensures efficient system performance. 2. High ratios can lead to: Overheating of compressor oil. Reduced refrigerant flow. Lower system capacity.  COMPRESSion RATIO EXAMPLE CALCULATION: Given: Low-side pressure = 49 psig High-side pressure = 278 psig Convert to psia: Low-side: 49 + 14.7 = 63.7 or 64 psia High-side: 278 + 14.7 = 292.7 or 293 psia Calculate Compression Ratio: 293 psia Compression Ratio = = 4.6 64 psia  COMPRESSion RATIO This means, the suction pressure is increased 4.6 times to reach the head pressure. This is expressed as 4.6-to-1 or 4.6:1  COMPRESSion RATIO SPECIFIC RATIOS Compressors are designed to operate efficiently within certain compression ratios. Following are the compression ratios of two other R22 applications: ▪︎ Air conditioning_(AC) compressor at 40°F evaporator and 125°F condensing = 3.5:1 ratio ▪︎ Freezer compressor at -20°F evaporator and 125°F condensing = 11.8:1  COMPRESSion RATIO WHY THE DIFFERENCE? Refrigeration systems often require more significant pressure increases because they operate at much lower temperatures compared to air- conditioning systems. This leads to higher compression ratios.  TWO STAGE OF COMPRESSION Two-stage compression is a process in which the compression of the refrigerant occurs in two steps, separated by an intercooling stage. TWO STAGE OF COMPRESSION PROCESS First Stage: The refrigerant is compressed from low pressure to an intermediate pressure. Intercooling: The refrigerant is cooled to reduce its temperature before the second stage of compression. This minimizes the work required by the second compressor. Second Stage: The refrigerant is further compressed to the condenser pressure. Types of compressor Reciprocating COMPRESSOR A reciprocating compressor, also known as a piston compressor, is a machine that uses pistons driven by a crankshaft to compress air. WELDED HERMETIC RECIPROCATING COMPRESSORS is a type of compressor commonly used in refrigeration and air conditioning systems. It is characterized by a fully sealed housing, typically made of steel, that is welded shut to prevent leakage of refrigerants and ensure long-term reliability. SEMI-HERMETIC COMPRESSORS is a type of refrigeration or air conditioning compressor where the motor and compressor are housed together in a single shell but are not completely sealed. Unlike hermetic compressors, which are welded shut and inaccessible for repairs, semi-hermetic compressors can be opened for maintenance or repairs because they use gaskets and bolts to seal the casing. belt-driven compressor is used to compress refrigerant gas, which is essential for the cooling and heating cycles in refrigeration and HVAC systems. Direct driven COMPRESSOR A direct-driven compressor is a type of air compressor where the motor or engine is directly connected to the compressor pump, typically through a single shaft. SCREW COMPRESSOR A screw compressor is a type of gas compressor that operates using a rotary mechanism, specifically a pair of interlocking helical rotors or screws. Rotary compressor a rotaty compresso, also known as an air compressor or refrigerant compresso, accepts low temperature refrigerant gas. After that, a revolving mechanism compresses it to a high-pressure gas, which is then passed through the accumulator’. scroll compressor Two spiral-shaped components compress refrigerant via a rotating interlocking action, resulting in quiet and efficient operation.  OPEN DRIVE COMPRESSORS The open drive compressor is a type of compressor that uses an external motor to drive the compressor through either a direct connection or a belt system. Its primary function is to compress gases (like air or refrigerants) for various industrial, commercial, or residential applications. CENTRIFUGAL COMPRESSOR a type of dynamic compressor used to increase the pressure of a gas by converting its kinetic energy into potential energy. Commonly used in a variety of industrial applications to compress gasses (such as air, natural gas, and refrigerants), its main role is to move gas around. Used extensively for air conditioning in large structures reciprocating compressor components reciprocating compressor components CRANKSHAFT CONNECTING ROD PISTONS REFRIGERANT CYLINDER VALVES (SUCTION) REFRIGERANT CYLINDER VALVES (DISCHARGE) COMPRESSOR HEAD MUFFLERS COMPRESSOR HOUSING crankshaft connecting rod pistons REFRIGERANT CYLINDER VALVES (SUCTION) Refrigerant cylinder valves (discharge) compressor head muffler compressor housing  belt-drive mechanisms A SYSTEM USED TO TRANSMIT MECHANICAL POWER OR MOTION BETWEEN TWO OR MORE ROTATING SHAFTS USING A FLEXIBLE BELT.  belt-drive mechanisms Suppose a motor with a pulley of 4 inches diameter runs at 1800 RPM and drives a machine with a pulley of 8 inches diameter. To find the driven RPM:  COMPRESSION PROCESS EXPANSION Piston is the highest point in the cylinder Compression is a process under which Referred to as top dead center volume of the system is gradually reduced, pressure and temperature increases where Both the suction and discharge heat transfer may or may not be possible. valves are closed While in expansion process volume is gradually decrease with the decrease in pressure and temperature and heat transfer Cylinder pressure is equal to may or may not be possible. discharge pressure As the crankshaft continues to turn, the piston moves down in the cylinder The volume in the cylinder increases The pressure of the refrigerant decreases  COMPRESSION PROCESS - As the piston moves down, the pressure decreases SUCTION When the cylinder pressure falls The compression process-suction below suction pressure, the suction is the stage in a compressor valve opens where the intake valve opens, allowing low-pressure gas or air to The discharge valve remains in the enter the compression chamber closed position before being compressed. As the piston continues downward, vapor from the suction line is pulled into the cylinder Suction continues until the piston reaches the lowest position in the cylinder (bottom dead center) At the bottom of the stroke, suction valves close  COMPRESSION PROCESS - COMPRESSION Piston starts to move upwards in the cylinder The suction valve closes and the discharge valve remains closed As the piston moves upwards, the volume in the cylinder decreases The pressure of the refrigerant increases Compression continues until the pressure in the cylinder rises just above discharge pressure  COMPRESSION PROCESS - DISCHARGE When the cylinder pressure rises above discharge pressure, the discharge valve opens and the suction valve remains closed As the piston continues to move upwards, the refrigerant is discharged from the compressor Discharge continues until the piston reaches top dead center LIQUID IN THE COMPRESSION CYLINDER If liquid enters the cylinder, damage will occur Liquid slugging can cause immediate damage to the compressor components Unlike gases, liquids are incompressible. Common causes of Liquid Slugging: A compressor is designed to handle gases, which are compressible and can Overfeeding metering device expand and contract as pressure is Poor Evaporator air circulation / applied. If liquid enters the cylinder, it Defective evaporator fan motor doesn’t compress, causing a pressure Low heat load buildup. Frosted evaporator coil  Reciprocating Compressor Efficiency Determined by initial compressor design Four processes takes place in compression process ▪︎Expansion (re-expansion) ▪︎Suction (intake) ▪︎Discharge ▪︎Compression  SYSTEM MAINTENANCE AND COMPRESSOR EFFICIENCY High suction pressures and low discharge pressures keep the compression ratio low Dirty evaporators cause suction pressure to drop Low suction reduces compressor pumping capacity Dirty condensers increase head pressure Compression ratio is increased by dirty or blocked condenser and evaporator coils Thank You