Refrigeration systems use a refrigerant that changes between gas and liquid states to remove heat from one area and release it to another area. The refrigerant absorbs heat in the evaporator, changing from liquid to gas. It is compressed to a high pressure gas and releases heat in the condenser, changing back to a liquid. The refrigerant then passes through a metering device and expansion valve back to the low pressure evaporator, completing the refrigeration cycle. Key components include the compressor, condenser, expansion valve, and evaporator. Refrigerant properties like saturation temperature and latent heat allow this heat transfer process to occur.
Refrigeration works by removing heat from a space using a refrigerant in a closed loop system. As the refrigerant absorbs heat, it changes state from a liquid to a gas. It is then condensed back to a liquid, releasing the heat. The four main components are the compressor, condenser, metering device, and evaporator. Refrigerants have saturation temperatures where they change state based on pressure. Proper refrigerant charging can be done using pressure/temperature charts and measuring subcooling or superheat.
Refrigeration systems use a refrigerant that undergoes phase changes to remove heat from one area and release it to another area. The basic refrigeration cycle involves four main components: a compressor, condenser, metering device, and evaporator. The refrigerant is compressed into a hot gas, condenses releasing heat, expands becoming cold, then evaporates absorbing heat before repeating the cycle. Technicians use pressure-temperature charts specific to the refrigerant type to determine proper system pressures and temperatures during operation and charging.
Air conditioning systems work by removing heat from indoor spaces and transferring it outdoors. They maintain indoor temperatures regardless of outdoor conditions. Refrigerators and air conditioners operate on the same principle - using a compressor, condenser coil, expansion valve and evaporator coil to move heat from inside to outside through the evaporation and condensation of refrigerant. As heat is removed, indoor spaces are cooled down in accordance with the second law of thermodynamics.
The document summarizes the refrigeration cycle. It describes the four basic processes: (1) isentropic compression in the compressor, (2) constant pressure heat rejection in the condenser, (3) isentropic expansion in the expansion valve/metering device, and (4) constant pressure heat addition in the evaporator. The refrigerant is compressed in the vapor phase, condensed, expanded, and evaporated alternately to provide cooling. Key components are the compressor, condenser, expansion valve, and evaporator. The coefficient of performance (COP) measures efficiency as the cooling effect divided by the work input. Selecting the right refrigerant depends on the application and factors like cost, toxicity, and environmental impact
The document summarizes the refrigeration cycle and vapor compression refrigeration system. The refrigeration cycle involves compressing a refrigerant gas, condensing it in a condenser to release heat, expanding the liquid refrigerant which causes it to evaporate and absorb heat, and circulating the cold gas back into the refrigerator. The vapor compression system uses this cycle, with the main components being a compressor, condenser, expansion valve, and evaporator. The compressor increases the refrigerant's pressure and temperature, the condenser cools and condenses it, releasing heat, the expansion valve reduces the pressure and temperature causing evaporation, and the evaporator absorbs heat during evaporation to cool its surroundings.
Refrigeration involves removing heat from one substance and transferring it to another. Heat naturally flows from hot to cold substances. Refrigerants are substances that absorb and transfer heat through a phase change process. Common refrigerants include pure ice, dry ice, and chemical refrigerants like R-22, each of which absorbs heat and changes phase at different fixed temperatures, allowing them to be used for cooling below the melting point of ice. Understanding the phase change properties of refrigerants is important for efficient refrigeration.
This document summarizes key concepts in refrigeration cycles. It defines refrigeration as reducing the temperature below the surroundings and notes that refrigerants, like NH3, are used as working fluids. It explains that the refrigerating effect is the energy removed from the cold chamber and that the coefficient of performance is the ratio of heat removed to work input. The document also discusses refrigerator capacity as the amount of heat transferred per unit time from the cold chamber. It provides an overview of the vapor compression refrigeration cycle and notes modifications to improve efficiency, such as replacing the expansion engine with a throttling valve.
The refrigeration cycle involves four steps - throttling, evaporation, compression, and condensation - that continuously cool a system. In throttling, pressure drops and the refrigerant becomes a liquid-vapor mixture. During evaporation, the mixture absorbs heat from surroundings as it changes to a vapor, providing cooling. Compression then increases the vapor's temperature and pressure. Finally, condensation releases excess heat, returning the refrigerant to a compressed liquid ready to repeat the cycle. The cycle exploits thermodynamic principles to power appliances like refrigerators and air conditioners through continuous heat removal.
Refrigeration works by removing heat from a space using a refrigerant in a closed loop system. As the refrigerant absorbs heat, it changes state from a liquid to a gas. It is then condensed back to a liquid, releasing the heat. The four main components are the compressor, condenser, metering device, and evaporator. Refrigerants have saturation temperatures where they change state based on pressure. Proper refrigerant charging can be done using pressure/temperature charts and measuring subcooling or superheat.
Refrigeration systems use a refrigerant that undergoes phase changes to remove heat from one area and release it to another area. The basic refrigeration cycle involves four main components: a compressor, condenser, metering device, and evaporator. The refrigerant is compressed into a hot gas, condenses releasing heat, expands becoming cold, then evaporates absorbing heat before repeating the cycle. Technicians use pressure-temperature charts specific to the refrigerant type to determine proper system pressures and temperatures during operation and charging.
Air conditioning systems work by removing heat from indoor spaces and transferring it outdoors. They maintain indoor temperatures regardless of outdoor conditions. Refrigerators and air conditioners operate on the same principle - using a compressor, condenser coil, expansion valve and evaporator coil to move heat from inside to outside through the evaporation and condensation of refrigerant. As heat is removed, indoor spaces are cooled down in accordance with the second law of thermodynamics.
The document summarizes the refrigeration cycle. It describes the four basic processes: (1) isentropic compression in the compressor, (2) constant pressure heat rejection in the condenser, (3) isentropic expansion in the expansion valve/metering device, and (4) constant pressure heat addition in the evaporator. The refrigerant is compressed in the vapor phase, condensed, expanded, and evaporated alternately to provide cooling. Key components are the compressor, condenser, expansion valve, and evaporator. The coefficient of performance (COP) measures efficiency as the cooling effect divided by the work input. Selecting the right refrigerant depends on the application and factors like cost, toxicity, and environmental impact
The document summarizes the refrigeration cycle and vapor compression refrigeration system. The refrigeration cycle involves compressing a refrigerant gas, condensing it in a condenser to release heat, expanding the liquid refrigerant which causes it to evaporate and absorb heat, and circulating the cold gas back into the refrigerator. The vapor compression system uses this cycle, with the main components being a compressor, condenser, expansion valve, and evaporator. The compressor increases the refrigerant's pressure and temperature, the condenser cools and condenses it, releasing heat, the expansion valve reduces the pressure and temperature causing evaporation, and the evaporator absorbs heat during evaporation to cool its surroundings.
Refrigeration involves removing heat from one substance and transferring it to another. Heat naturally flows from hot to cold substances. Refrigerants are substances that absorb and transfer heat through a phase change process. Common refrigerants include pure ice, dry ice, and chemical refrigerants like R-22, each of which absorbs heat and changes phase at different fixed temperatures, allowing them to be used for cooling below the melting point of ice. Understanding the phase change properties of refrigerants is important for efficient refrigeration.
This document summarizes key concepts in refrigeration cycles. It defines refrigeration as reducing the temperature below the surroundings and notes that refrigerants, like NH3, are used as working fluids. It explains that the refrigerating effect is the energy removed from the cold chamber and that the coefficient of performance is the ratio of heat removed to work input. The document also discusses refrigerator capacity as the amount of heat transferred per unit time from the cold chamber. It provides an overview of the vapor compression refrigeration cycle and notes modifications to improve efficiency, such as replacing the expansion engine with a throttling valve.
The refrigeration cycle involves four steps - throttling, evaporation, compression, and condensation - that continuously cool a system. In throttling, pressure drops and the refrigerant becomes a liquid-vapor mixture. During evaporation, the mixture absorbs heat from surroundings as it changes to a vapor, providing cooling. Compression then increases the vapor's temperature and pressure. Finally, condensation releases excess heat, returning the refrigerant to a compressed liquid ready to repeat the cycle. The cycle exploits thermodynamic principles to power appliances like refrigerators and air conditioners through continuous heat removal.
The basic refrigeration cycle involves four main processes: 1) compression, where a refrigerant is compressed into a high-pressure gas, 2) condensation, where the high-pressure gas condenses into a liquid and releases heat, 3) expansion, where the high-pressure liquid passes through an expansion valve and decreases in pressure, and 4) evaporation, where the low-pressure liquid absorbs heat and evaporates back into a gas to be compressed and repeat the cycle. This cycle exploits how gases give off heat when condensed and liquids absorb heat when evaporated to provide cooling.
Presentation Outline:-
The Principles of Basic Refrigeration
Basic Refrigeration Cycle
There are countless applications for refrigeration plants now.
How do things get colder
Main Components
Accessories
Pressure
Pressure And Temperature
Refrigerator used for Cooling
Analysis of the Carnot Refrigerator
Terminology
The Vapor Compression Refrigeration Cycle
The Pressure-Enthalpy Diagram
Vapor Compression Refrigeration Analysis
VCR Cycle Irreversibilities
The document discusses refrigeration systems, including vapor refrigeration systems like the Carnot cycle and vapor compression refrigeration systems (VCRS). It also covers absorption refrigeration systems, which use a secondary substance called an absorbent to absorb the refrigerant into a liquid solution rather than compressing it. Absorption systems have lower work input compared to vapor compression. A common example is the ammonia-water absorption refrigeration system, which uses ammonia as the refrigerant and water as the absorbent.
Vapor-compression refrigerators are manufactured through a process of cutting, bending, painting, and assembling metal sheets to form the internal and external parts. Components like the evaporator, condenser, expansion valve, and thermostat are attached to complete the refrigeration cycle. Refrigerators typically last 10-16 years before recycling, which involves removing coolant and separating materials. Ergonomic designs place frequently accessed parts at waist level for ease of use.
This document provides an overview of a training session on energy equipment refrigeration and air conditioning systems. It discusses types of refrigeration including vapor compression and vapor absorption. It also covers assessing the performance of refrigeration and air conditioning systems, such as measuring tons of refrigeration and coefficient of performance. Finally, it lists several energy efficiency opportunities for refrigeration and AC systems, such as optimizing heat exchange, multi-staging systems, and capacity control of compressors.
Basics of refrigeration engineering section bAkshit Kohli
i hope, it will helpful to the students and peoples in the search of topics mentioned
it is informative to study to even get passing marks or for revision
This document provides an overview of refrigeration systems and their main components. It discusses how refrigeration works by removing heat from spaces or objects using a mechanical process. The key parts of a refrigeration system are described as the compressor, condenser, expansion valve, and evaporator. The compressor increases the pressure and temperature of the refrigerant vapor. The condenser cools and condenses the refrigerant into a liquid. The expansion valve controls the flow of liquid refrigerant into the evaporator. In the evaporator, the refrigerant absorbs heat from its surroundings as it vaporizes, thus cooling the environment.
This document provides information on refrigeration and air conditioning. It defines refrigeration as the process of transferring heat from a low temperature region to a high temperature region. The key components and working principles of vapor compression and vapor absorption refrigeration systems are described. It also discusses terms used in air conditioning like dry bulb temperature, wet bulb temperature, and relative humidity. The layout and working of a basic window room air conditioner is explained. Domestic refrigerators like single door, two-door, and their components are outlined.
This document describes refrigeration cycles, including the Carnot refrigeration cycle, ideal vapor-compression cycle, actual vapor-compression cycle, and cascade refrigeration cycle. It discusses key components like the evaporator, condenser, compressor, and expansion valve. It explains processes like compression, heat rejection, throttling, and evaporation. Important concepts covered include the coefficient of performance (COP) and how irreversibilities reduce the COP from the theoretical Carnot cycle value. Refrigerant properties and selection criteria are also outlined.
Vapour compression refrigeration systems are the most commonly used refrigeration systems. They use a circulating refrigerant that undergoes phase changes to absorb heat from the space being cooled and reject it elsewhere. The key components are a compressor, condenser, thermal expansion valve, and evaporator. The refrigerant is compressed in the compressor, condenses while rejecting heat in the condenser, expands in the thermal expansion valve where some evaporates, and evaporates fully while absorbing heat in the evaporator before returning to the compressor to complete the cycle. These systems have high efficiency and can be used for a wide range of temperatures but have higher initial costs and require preventing refrigerant leakage.
This document discusses refrigeration and heat engines. It describes key components of a vapor compression refrigeration system including the compressor, condenser, expansion valve, and evaporator. The vapor compression system uses a refrigerant that is compressed to a high pressure and temperature gas, condensed to a high pressure liquid, expanded to a low pressure liquid-gas mixture, and evaporated to absorb heat. The document compares vapor compression to air refrigeration systems, noting advantages of vapor compression including smaller size, higher efficiency, and use over a wider temperature range.
Refrigeration and air conditioning systems work by removing heat from an enclosed space to lower its temperature below the surrounding environment. There are two main types of refrigeration systems - vapor compression cycles and vapor absorption cycles. Vapor compression cycles use a compressor, condenser, expansion valve, and evaporator to remove heat. Vapor absorption cycles use heat to drive the refrigeration process rather than electricity. Air conditioning systems build on refrigeration principles to simultaneously control temperature, humidity, air motion, and quality within an enclosed space.
The document discusses refrigeration and air conditioning. It defines refrigeration as the process of transferring heat from a low temperature region to a high temperature region to cool a substance. The principle of refrigeration is based on the second law of thermodynamics, which states that heat does not flow from a low to high temperature body without external work. It then describes the vapor compression refrigeration system, which uses a compressor, condenser, expansion valve and evaporator. Current refrigeration methods discussed are vapor compression and vapor absorption. Vapor absorption uses a heat source rather than electricity. Air conditioning alters properties like temperature and humidity of air for comfort or industrial processes, regardless of external conditions. Different types of air conditioning systems are also outlined
This document provides information about refrigeration, air conditioning, and psychrometrics. It defines refrigeration as maintaining a system below the surrounding temperature by removing heat. Mechanical refrigeration uses the evaporation of liquids in a vapor compression cycle consisting of an evaporator, compressor, condenser and expansion valve. Applications include food preservation, industrial processes, and comfort cooling. Air conditioning works similarly but also controls humidity using psychrometric processes like dehumidification and humidification.
Applications of Refrigeration and Air Conditioning & RefrigerantsNITIN AHER
This document discusses refrigeration and air conditioning. It describes how refrigeration cools products or spaces below the surrounding temperature, while air conditioning controls temperature, moisture, cleanliness, odor, and air circulation for occupants or processes. Common applications are listed such as room air conditioners, refrigerators, evaporative coolers, and commercial refrigeration/air conditioning. The document then focuses on evaporative cooling systems, automotive air conditioners, refrigerants used, and criteria for selecting refrigerants including thermodynamic properties, environmental impact, and safety.
This document provides an active learning assignment on refrigeration for an elements of mechanical engineering course. It includes an introduction to refrigeration, how refrigeration systems work, common refrigerants, the unit of refrigeration, applications, and the two main types of refrigeration systems - vapor compression and vapor absorption. The vapor compression refrigeration cycle is explained in detail through labeled diagrams showing the four processes of expansion, vaporization, compression, and condensation.
This document summarizes the basic components and process of a refrigeration cycle. It outlines the four main components: compressor, condenser, metering device, and evaporator. It describes that the compressor increases the pressure and temperature of the refrigerant vapor from the evaporator. In the condenser, heat is removed from the refrigerant as it cools and changes state into a liquid. The metering device then regulates the flow of refrigerant into the evaporator, where it absorbs heat from the surrounding air and changes back into a vapor before returning to the compressor to repeat the cycle.
The vapor compression refrigeration cycle is commonly used to transfer heat from a low temperature medium to a high temperature medium. It involves four main processes: (1) compression of a refrigerant vapor, (2) heat rejection in a condenser, (3) expansion of the refrigerant through a throttle valve, and (4) heat absorption in an evaporator. The coefficient of performance (COP) is used to measure the efficiency of refrigerators and heat pumps. Actual vapor compression cycles are less efficient than the ideal Carnot cycle due to irreversibilities.
This document discusses vapor compression refrigeration systems. It begins by defining refrigerators and heat pumps, then describes the basic vapor compression refrigeration cycle which uses four main components: an evaporator, compressor, condenser, and expansion valve. Various refrigerants are discussed, along with their ideal properties. A pressure-enthalpy diagram is presented to illustrate the vapor compression refrigeration cycle process. Methods to improve the system's efficiency through liquid subcooling and vapor superheating are also covered.
The document discusses the science of psychrometry, which deals with air-water vapor mixtures. It defines key psychrometric properties like dry bulb temperature, wet bulb temperature, dew point, relative humidity, and specific humidity. It also explains various psychrometric processes like sensible heating and cooling, humidification, dehumidification, and adiabatic mixing. The psychrometric chart is introduced as a tool for analyzing these processes. Finally, the document discusses factors that affect human thermal comfort like air temperature, humidity, and heat transfer methods in buildings.
1) Refrigeration and air conditioning systems use a vapor compression cycle to transfer heat from cool spaces to warm spaces. They circulate a refrigerant between an evaporator, compressor, condenser and expansion valve.
2) In the evaporator, the refrigerant absorbs heat from cool spaces and changes state from liquid to vapor. The compressor increases the refrigerant's pressure and temperature. In the condenser, the refrigerant releases heat to warm spaces and changes state from vapor to liquid.
3) The expansion valve reduces the refrigerant's pressure, lowering its temperature. This allows it to absorb more heat in the evaporator and continue the cooling cycle. Proper refrigerant selection and system design are important
Refrigeration is the process of maintaining temperatures below the surrounding atmosphere. It involves removing heat from an area to be cooled using a vapor compression cycle. A summary of key points:
- Refrigeration is used to preserve food by stopping bacterial growth below 5°C. Early methods involved natural ice or cold wells.
- Refrigeration systems are based on the second law of thermodynamics, requiring external work to transfer heat from a lower to higher temperature.
- A vapor compression cycle involves compressing a refrigerant vapor to a high pressure and temperature, condensing it to release heat, then expanding it to absorb heat before repeating the cycle.
- Common household refrigerators use the vapor compression
The basic refrigeration cycle involves four main processes: 1) compression, where a refrigerant is compressed into a high-pressure gas, 2) condensation, where the high-pressure gas condenses into a liquid and releases heat, 3) expansion, where the high-pressure liquid passes through an expansion valve and decreases in pressure, and 4) evaporation, where the low-pressure liquid absorbs heat and evaporates back into a gas to be compressed and repeat the cycle. This cycle exploits how gases give off heat when condensed and liquids absorb heat when evaporated to provide cooling.
Presentation Outline:-
The Principles of Basic Refrigeration
Basic Refrigeration Cycle
There are countless applications for refrigeration plants now.
How do things get colder
Main Components
Accessories
Pressure
Pressure And Temperature
Refrigerator used for Cooling
Analysis of the Carnot Refrigerator
Terminology
The Vapor Compression Refrigeration Cycle
The Pressure-Enthalpy Diagram
Vapor Compression Refrigeration Analysis
VCR Cycle Irreversibilities
The document discusses refrigeration systems, including vapor refrigeration systems like the Carnot cycle and vapor compression refrigeration systems (VCRS). It also covers absorption refrigeration systems, which use a secondary substance called an absorbent to absorb the refrigerant into a liquid solution rather than compressing it. Absorption systems have lower work input compared to vapor compression. A common example is the ammonia-water absorption refrigeration system, which uses ammonia as the refrigerant and water as the absorbent.
Vapor-compression refrigerators are manufactured through a process of cutting, bending, painting, and assembling metal sheets to form the internal and external parts. Components like the evaporator, condenser, expansion valve, and thermostat are attached to complete the refrigeration cycle. Refrigerators typically last 10-16 years before recycling, which involves removing coolant and separating materials. Ergonomic designs place frequently accessed parts at waist level for ease of use.
This document provides an overview of a training session on energy equipment refrigeration and air conditioning systems. It discusses types of refrigeration including vapor compression and vapor absorption. It also covers assessing the performance of refrigeration and air conditioning systems, such as measuring tons of refrigeration and coefficient of performance. Finally, it lists several energy efficiency opportunities for refrigeration and AC systems, such as optimizing heat exchange, multi-staging systems, and capacity control of compressors.
Basics of refrigeration engineering section bAkshit Kohli
i hope, it will helpful to the students and peoples in the search of topics mentioned
it is informative to study to even get passing marks or for revision
This document provides an overview of refrigeration systems and their main components. It discusses how refrigeration works by removing heat from spaces or objects using a mechanical process. The key parts of a refrigeration system are described as the compressor, condenser, expansion valve, and evaporator. The compressor increases the pressure and temperature of the refrigerant vapor. The condenser cools and condenses the refrigerant into a liquid. The expansion valve controls the flow of liquid refrigerant into the evaporator. In the evaporator, the refrigerant absorbs heat from its surroundings as it vaporizes, thus cooling the environment.
This document provides information on refrigeration and air conditioning. It defines refrigeration as the process of transferring heat from a low temperature region to a high temperature region. The key components and working principles of vapor compression and vapor absorption refrigeration systems are described. It also discusses terms used in air conditioning like dry bulb temperature, wet bulb temperature, and relative humidity. The layout and working of a basic window room air conditioner is explained. Domestic refrigerators like single door, two-door, and their components are outlined.
This document describes refrigeration cycles, including the Carnot refrigeration cycle, ideal vapor-compression cycle, actual vapor-compression cycle, and cascade refrigeration cycle. It discusses key components like the evaporator, condenser, compressor, and expansion valve. It explains processes like compression, heat rejection, throttling, and evaporation. Important concepts covered include the coefficient of performance (COP) and how irreversibilities reduce the COP from the theoretical Carnot cycle value. Refrigerant properties and selection criteria are also outlined.
Vapour compression refrigeration systems are the most commonly used refrigeration systems. They use a circulating refrigerant that undergoes phase changes to absorb heat from the space being cooled and reject it elsewhere. The key components are a compressor, condenser, thermal expansion valve, and evaporator. The refrigerant is compressed in the compressor, condenses while rejecting heat in the condenser, expands in the thermal expansion valve where some evaporates, and evaporates fully while absorbing heat in the evaporator before returning to the compressor to complete the cycle. These systems have high efficiency and can be used for a wide range of temperatures but have higher initial costs and require preventing refrigerant leakage.
This document discusses refrigeration and heat engines. It describes key components of a vapor compression refrigeration system including the compressor, condenser, expansion valve, and evaporator. The vapor compression system uses a refrigerant that is compressed to a high pressure and temperature gas, condensed to a high pressure liquid, expanded to a low pressure liquid-gas mixture, and evaporated to absorb heat. The document compares vapor compression to air refrigeration systems, noting advantages of vapor compression including smaller size, higher efficiency, and use over a wider temperature range.
Refrigeration and air conditioning systems work by removing heat from an enclosed space to lower its temperature below the surrounding environment. There are two main types of refrigeration systems - vapor compression cycles and vapor absorption cycles. Vapor compression cycles use a compressor, condenser, expansion valve, and evaporator to remove heat. Vapor absorption cycles use heat to drive the refrigeration process rather than electricity. Air conditioning systems build on refrigeration principles to simultaneously control temperature, humidity, air motion, and quality within an enclosed space.
The document discusses refrigeration and air conditioning. It defines refrigeration as the process of transferring heat from a low temperature region to a high temperature region to cool a substance. The principle of refrigeration is based on the second law of thermodynamics, which states that heat does not flow from a low to high temperature body without external work. It then describes the vapor compression refrigeration system, which uses a compressor, condenser, expansion valve and evaporator. Current refrigeration methods discussed are vapor compression and vapor absorption. Vapor absorption uses a heat source rather than electricity. Air conditioning alters properties like temperature and humidity of air for comfort or industrial processes, regardless of external conditions. Different types of air conditioning systems are also outlined
This document provides information about refrigeration, air conditioning, and psychrometrics. It defines refrigeration as maintaining a system below the surrounding temperature by removing heat. Mechanical refrigeration uses the evaporation of liquids in a vapor compression cycle consisting of an evaporator, compressor, condenser and expansion valve. Applications include food preservation, industrial processes, and comfort cooling. Air conditioning works similarly but also controls humidity using psychrometric processes like dehumidification and humidification.
Applications of Refrigeration and Air Conditioning & RefrigerantsNITIN AHER
This document discusses refrigeration and air conditioning. It describes how refrigeration cools products or spaces below the surrounding temperature, while air conditioning controls temperature, moisture, cleanliness, odor, and air circulation for occupants or processes. Common applications are listed such as room air conditioners, refrigerators, evaporative coolers, and commercial refrigeration/air conditioning. The document then focuses on evaporative cooling systems, automotive air conditioners, refrigerants used, and criteria for selecting refrigerants including thermodynamic properties, environmental impact, and safety.
This document provides an active learning assignment on refrigeration for an elements of mechanical engineering course. It includes an introduction to refrigeration, how refrigeration systems work, common refrigerants, the unit of refrigeration, applications, and the two main types of refrigeration systems - vapor compression and vapor absorption. The vapor compression refrigeration cycle is explained in detail through labeled diagrams showing the four processes of expansion, vaporization, compression, and condensation.
This document summarizes the basic components and process of a refrigeration cycle. It outlines the four main components: compressor, condenser, metering device, and evaporator. It describes that the compressor increases the pressure and temperature of the refrigerant vapor from the evaporator. In the condenser, heat is removed from the refrigerant as it cools and changes state into a liquid. The metering device then regulates the flow of refrigerant into the evaporator, where it absorbs heat from the surrounding air and changes back into a vapor before returning to the compressor to repeat the cycle.
The vapor compression refrigeration cycle is commonly used to transfer heat from a low temperature medium to a high temperature medium. It involves four main processes: (1) compression of a refrigerant vapor, (2) heat rejection in a condenser, (3) expansion of the refrigerant through a throttle valve, and (4) heat absorption in an evaporator. The coefficient of performance (COP) is used to measure the efficiency of refrigerators and heat pumps. Actual vapor compression cycles are less efficient than the ideal Carnot cycle due to irreversibilities.
This document discusses vapor compression refrigeration systems. It begins by defining refrigerators and heat pumps, then describes the basic vapor compression refrigeration cycle which uses four main components: an evaporator, compressor, condenser, and expansion valve. Various refrigerants are discussed, along with their ideal properties. A pressure-enthalpy diagram is presented to illustrate the vapor compression refrigeration cycle process. Methods to improve the system's efficiency through liquid subcooling and vapor superheating are also covered.
The document discusses the science of psychrometry, which deals with air-water vapor mixtures. It defines key psychrometric properties like dry bulb temperature, wet bulb temperature, dew point, relative humidity, and specific humidity. It also explains various psychrometric processes like sensible heating and cooling, humidification, dehumidification, and adiabatic mixing. The psychrometric chart is introduced as a tool for analyzing these processes. Finally, the document discusses factors that affect human thermal comfort like air temperature, humidity, and heat transfer methods in buildings.
1) Refrigeration and air conditioning systems use a vapor compression cycle to transfer heat from cool spaces to warm spaces. They circulate a refrigerant between an evaporator, compressor, condenser and expansion valve.
2) In the evaporator, the refrigerant absorbs heat from cool spaces and changes state from liquid to vapor. The compressor increases the refrigerant's pressure and temperature. In the condenser, the refrigerant releases heat to warm spaces and changes state from vapor to liquid.
3) The expansion valve reduces the refrigerant's pressure, lowering its temperature. This allows it to absorb more heat in the evaporator and continue the cooling cycle. Proper refrigerant selection and system design are important
Refrigeration is the process of maintaining temperatures below the surrounding atmosphere. It involves removing heat from an area to be cooled using a vapor compression cycle. A summary of key points:
- Refrigeration is used to preserve food by stopping bacterial growth below 5°C. Early methods involved natural ice or cold wells.
- Refrigeration systems are based on the second law of thermodynamics, requiring external work to transfer heat from a lower to higher temperature.
- A vapor compression cycle involves compressing a refrigerant vapor to a high pressure and temperature, condensing it to release heat, then expanding it to absorb heat before repeating the cycle.
- Common household refrigerators use the vapor compression
- Refrigeration systems use a closed loop pipe system to circulate refrigerants between four main components: an evaporator, compressor, condenser, and metering device.
- In the evaporator, the refrigerant absorbs heat from the surrounding air/space, causing it to evaporate from a liquid to a gas and raising its temperature to the saturation point. The compressor then increases the pressure and temperature of the vapor.
- In the condenser, the hot vapor releases its heat energy and condenses back to a liquid. The metering device controls the flow of liquid refrigerant back to the evaporator to repeat the cooling cycle. This process exploits the physical properties of refrigerants and
The document summarizes the main components of an air conditioning system and how they work together in the refrigeration cycle. It describes the compressor, condenser, evaporator, thermostatic expansion valve, and accumulator. The compressor increases pressure and temperature of the refrigerant vapor. The condenser liquefies the vapor. The evaporator absorbs heat from the air being conditioned and boils the refrigerant. The thermostatic expansion valve controls the flow of liquid refrigerant into the evaporator. The accumulator separates vapor and oil from the liquid refrigerant before it returns to the compressor.
1. Refrigeration systems use the vapor compression cycle to pump heat from a low temperature space to a higher temperature space, lowering the temperature in the process.
2. A refrigerator uses this cycle, with a compressor, condenser, expansion valve, and evaporator to absorb heat from the refrigerated space and reject it outside.
3. Domestic refrigerators are small, self-contained refrigeration units commonly used in homes to provide low temperatures for food storage and preservation on a short term basis.
This document provides an overview of refrigeration systems. It begins with definitions of refrigeration and refrigeration cycles. It then describes the main components of a vapor compression refrigeration system, including the compressor, condenser, expansion valve, and evaporator. The document explains how each component functions and how refrigerant moves through the system. It also discusses domestic refrigerators and their components and electrical circuits. The document aims to explain the basic concepts and components of refrigeration systems.
This document discusses the process of vapor compression refrigeration. It describes the key components of a vapor compression system including the evaporator, compressor, condenser, and expansion valve. The refrigeration cycle is explained where refrigerant in the evaporator absorbs heat and changes from liquid to gas. The gas is compressed in the compressor and condensed in the condenser before passing through the expansion valve back to the evaporator. The document provides details on each component and how they work together in the refrigeration process.
In this power-point presentation, you'll understand the basic concepts & mechanisms of a fridge/refrigerator.
This is a short ppt in simple english language for easy & quick understanding of concepts.
Hope, it'll be helpful to you
THANKYOU :)
1. Study the vapor compression refrigeration cycle.docxsydur10
The document summarizes the components and process of a vapor compression refrigeration cycle. It identifies the main components as the evaporator, compressor, condenser, and throttling device. It describes the basic process of how each component functions in the refrigeration cycle, including how the refrigerant changes states and transfers heat at different points in the cycle. The objective is to study and observe the refrigeration cycle in action, including measuring pressures and temperatures at different points to understand how it provides cooling.
Scotsman ice machine refrigeration training 101 - 0218.pptssuser0c24d5
This document provides an overview of refrigeration concepts and Scotsman equipment. It defines basic refrigeration terminology and components of a vapor compression system including the compressor, condenser, expansion device, evaporator and refrigerants. It explains the refrigeration cycle of freezing and harvesting ice. Key concepts are also summarized such as superheat, subcooling, pressure-temperature relationships and common units of measurement. The document outlines Scotsman ice making equipment and refrigeration systems for batch cubers and continuous flakers/nuggets. It introduces Scotsman refrigeration training courses that provide further details on equipment design and engineering processes.
Scotsman ice machine refrigeration training 101 - 0218.pptMaskiNano
This document provides an overview of refrigeration concepts and Scotsman equipment. It defines the basic refrigeration cycle and components including the compressor, condenser, expansion device, and evaporator. It explains key refrigeration terms like superheat and subcooling. It also outlines Scotsman ice maker models, their refrigeration systems, control sensors, freeze and harvest cycles, and engineering training courses. The document serves as an introduction to refrigeration systems and Scotsman equipment operations.
Scotsman ice machine refrigeration training 101 - 0218.pptJigneshChhatbar1
This document provides an overview of refrigeration concepts and Scotsman refrigeration systems. It defines common refrigeration terms and components of a basic vapor compression cycle. These include the compressor, condenser, thermal expansion valve, evaporator, and refrigerants. The document explains refrigeration units of measure and the refrigeration cycle processes of freezing and harvesting ice. It also covers refrigeration principles such as superheat, subcooling, and crankcase differential pressure. Finally, it introduces more advanced topics that will be covered in Scotsman Refrigeration 201, including different ice maker configurations and control systems.
This document discusses refrigeration systems and their components. It describes that refrigeration is the process of removing heat from a substance or space to lower its temperature. There are three main refrigeration systems: vapor compression, vapor absorption, and thermo-electric. The vapor compression system is the most commonly used and works by changing a refrigerant between vapor and liquid phases using a compressor, condenser, evaporator, and expansion device. Key factors in selecting a refrigerant include its latent heat of vaporization, condensing pressure, and toxicity. The document outlines the purpose and types of the main components of a refrigeration system. Finally, it defines refrigeration load as the rate of heat removal needed to maintain a space's temperature and
The document describes the auxiliary PRDS (pressure reducing and desuperheating) system used in thermal power plants. It has two identical systems - the turbine auxiliary steam system (TAS) and boiler auxiliary steam system (BAS). Low and high capacity auxiliary steam is derived from main steam and its pressure and temperature are reduced before supplying it to various locations in the plant for processes like deaeration, soot blowing, oil heating etc. The systems use control valves, isolating valves, desuperheaters and spray water to control pressure and temperature.
This document discusses cleaning in place (CIP) procedures for freezer and refrigeration components. It explains that CIP involves circulating cleaning solutions like alkaline washes and acid rinses through equipment to remove residues. Key parameters that must be controlled include time, temperature, chemical concentration, flow rates, and pressures. The document provides details on CIP processes for items like tanks, pipes, filters and how to assess cleanliness. Turbulent flow above a certain velocity is important for effective mechanical cleaning action during CIP cycles.
سمنار الثرمو النهائي 2023 THYROMDYNAMIC.pptxhusseinalnasry
The document discusses the vapor compression refrigeration cycle. It operates by using a refrigerant that alternately vaporizes and condenses. As a liquid, it absorbs heat during evaporation, and as a gas it releases heat during condensation. The ideal vapor compression cycle involves isentropic compression, constant pressure heat rejection, throttling through an expansion valve, and constant pressure heat addition. The cycle uses a compressor, condenser, expansion valve, and evaporator to transfer heat from a low temperature region to a higher one. The efficiency of refrigerators and heat pumps is expressed through the coefficient of performance.
The document discusses refrigeration and air conditioning. It defines refrigeration as the process of transferring heat from a low temperature region to a high temperature region. The principle of refrigeration is based on the second law of thermodynamics. A vapor compression refrigeration system uses a compressor, condenser, expansion valve, and evaporator to cool a substance. An air conditioning system controls properties of air like temperature, humidity, and air flow in an enclosed space. It discusses components of window air conditioners and split air conditioners.
The document summarizes the basic vapor compression refrigeration cycle. It consists of four main processes: (1) compression of refrigerant vapor in a compressor, (2) condensation of the high-pressure vapor into a liquid in a condenser, (3) expansion of the high-pressure liquid through a throttling valve or expansion device, and (4) evaporation of the low-pressure liquid in an evaporator. The refrigerant absorbs heat from the evaporator and releases heat in the condenser, allowing for transfer of heat from low to high temperature regions. The coefficient of performance (COP) measures the efficiency of the cycle. Proper selection of refrigerant depends on the application.
The document describes the key components and processes in a vapor absorption refrigeration system:
1) An evaporator where refrigerant vaporizes and absorbs heat, 2) An absorber where refrigerant vapor is absorbed by an absorbent, releasing heat, 3) A generator where heat regenerates the refrigerant and absorbent, and 4) A condenser where refrigerant condenses and liquefies. Heat from a heat source like steam drives the process without the need for a compressor.
This document discusses condensers in refrigeration systems. It describes the purpose of condensers to reject heat from the refrigerant. Water-cooled and air-cooled condensers are described. Water-cooled condensers can be tube within a tube, shell and coil, or shell and tube designs. Recirculating water systems use cooling towers to cool the water, while wastewater systems discharge used water. Air-cooled condensers rely on ambient air to remove heat. Controls are needed for low ambient operation to maintain proper system pressures.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Applications of artificial Intelligence in Mechanical Engineering.pdfAtif Razi
Historically, mechanical engineering has relied heavily on human expertise and empirical methods to solve complex problems. With the introduction of computer-aided design (CAD) and finite element analysis (FEA), the field took its first steps towards digitization. These tools allowed engineers to simulate and analyze mechanical systems with greater accuracy and efficiency. However, the sheer volume of data generated by modern engineering systems and the increasing complexity of these systems have necessitated more advanced analytical tools, paving the way for AI.
AI offers the capability to process vast amounts of data, identify patterns, and make predictions with a level of speed and accuracy unattainable by traditional methods. This has profound implications for mechanical engineering, enabling more efficient design processes, predictive maintenance strategies, and optimized manufacturing operations. AI-driven tools can learn from historical data, adapt to new information, and continuously improve their performance, making them invaluable in tackling the multifaceted challenges of modern mechanical engineering.
artificial intelligence and data science contents.pptxGauravCar
What is artificial intelligence? Artificial intelligence is the ability of a computer or computer-controlled robot to perform tasks that are commonly associated with the intellectual processes characteristic of humans, such as the ability to reason.
› ...
Artificial intelligence (AI) | Definitio
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
Null Bangalore | Pentesters Approach to AWS IAMDivyanshu
#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
- Basic understanding of AWS services and architecture
- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
# Scenario Covered:
- Basics of IAM in AWS
- Implementing IAM Policies with Least Privilege to Manage S3 Bucket
- Objective: Create an S3 bucket with least privilege IAM policy and validate access.
- Steps:
- Create S3 bucket.
- Attach least privilege policy to IAM user.
- Validate access.
- Exploiting IAM PassRole Misconfiguration
-Allows a user to pass a specific IAM role to an AWS service (ec2), typically used for service access delegation. Then exploit PassRole Misconfiguration granting unauthorized access to sensitive resources.
- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
- Steps:
- Allow user to pass IAM role to EC2.
- Exploit misconfiguration for unauthorized access.
- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
2. Basics
• Refrigeration is the removal of heat from a material or space, so that
it’s temperature is lower than that of it’s surroundings.
• When refrigerant absorbs the unwanted heat, this raises the
refrigerant’s temperature (“Saturation Temperature”) so that it
changes from a liquid to a gas — it evaporates. The system then
uses condensation to release the heat and change the refrigerant
back into a liquid. This is called “Latent Heat”.
• This cycle is based on the physical principle, that a liquid extracts
heat from the surrounding area as it expands (boils) into a gas.
• To accomplish this, the refrigerant is pumped through a closed
looped pipe system.
• The closed looped pipe system stops the refrigerant from becoming
contaminated and controls its stream. The refrigerant will be both a
vapor and a liquid in the loop.
3. “Saturation Temperature” – can be defined as the temperature of a
liquid, vapor, or a solid, where if any heat is added or removed, a
change of state takes place.
• A change of state transfers a large
amount of energy.
• At saturation temperature, materials are
sensitive to additions or removal of heat.
• Water is an example of how saturation
property of a material, can transfer a
large amount of heat.
• Refrigerants use the same principles as
ice. For any given pressure, refrigerants
have a saturation temperature.
• If the pressure is low, the saturation
temperature is low. If pressure is high,
saturation temperature is high.
4. “Latent Heat”- The heat required to change a liquid to a gas (or the heat
that must be removed from a gas to condense it to a liquid), without any
change in temperature.
• Heat is a form of energy that is
transferred from one object to
another object.
• Heat Is a form of energy transferred
by a difference in temperature.
• Heat transfer can occur, when there
is a temperature difference between
two or more objects. Heat will only
flow from a warm object to a colder
object.
• The heat transfer is greatest, when
there is a large temperature
difference between two objects.
5. The Refrigeration Cycle
There are four main components in
a refrigeration system:
• The Compressor
• The Condensing Coil
• The Metering Device
• The Evaporator
• Two different pressures exist in the
refrigeration cycle. The evaporator
or low pressure, in the "low side"
and the condenser, or high
pressure, in the "high side". These
pressure areas are divided by the
other two components. On one
end, is the metering device which
controls the refrigerant flow, and on
the other end, is the compressor.
6. The Compressor
• The compressor is the heart of the
system. The compressor does just
what it’s name is. It compresses
the low pressure refrigerant vapor
from the evaporator and
compresses it into a high pressure
vapor.
• The inlet to the compressor is
called the “Suction Line”. It brings
the low pressure vapor into the
compressor.
• After the compressor compresses
the refrigerant into a high pressure
Vapor, it removes it to the outlet
called the “Discharge Line”.
7. The Condenser
• The “Discharge Line” leaves the
compressor and runs to the inlet of the
condenser.
• Because the refrigerant was compressed,
it is a hot high pressure vapor (as
pressure goes up – temperature goes
up).
• The hot vapor enters the condenser and
starts to flow through the tubes.
• Cool air is blown across the out side of
the finned tubes of the condenser
(usually by a fan or water with a pump).
• Since the air is cooler than the
refrigerant, heat jumps from the tubing to
the cooler air (energy goes from hot to
cold – “latent heat”).
• As the heat is removed from the
refrigerant, it reaches it’s “saturated
temperature” and starts to “flash”
(change states), into a high pressure
liquid.
• The high pressure liquid leaves the
condenser through the “liquid line” and
travels to the “metering device”.
Sometimes running through a filter dryer
first, to remove any dirt or foreign
particles.
8. Metering Devices
• Metering devices regulate how much
liquid refrigerant enters the evaporator .
• Common used metering devices are,
small thin copper tubes referred to as
“cap tubes”, thermally controller
diaphragm valves called “TXV’s” (thermal
expansion valves) and single opening
“orifices”.
• The metering device tries to maintain a
preset temperature difference or “super
heat”, between the inlet and outlet
openings of the evaporator.
• As the metering devices regulates the
amount of refrigerant going into the
evaporator, the device lets small
amounts of refrigerant out into the line
and looses the high pressure it has
behind it.
• Now we have a low pressure, cooler
liquid refrigerant entering the evaporative
coil (pressure went down – so
temperature goes down).
9. Thermal expansion Valves
• A very common type of metering device is
called a TX Valve (Thermostatic Expansion
Valve). This valve has the capability of
controlling the refrigerant flow. If the load on
the evaporator changes, the valve can
respond to the change and increase or
decrease the flow accordingly.
• The TXV has a sensing bulb attached to the
outlet of the evaporator. This bulb senses the
suction line temperature and sends a signal
to the TXV allowing it to adjust the flow rate.
This is important because, if not all, the
refrigerant in the evaporator changes state
into a gas, there could be liquid refrigerant
content returning to the compressor. This
can be fatal to the compressor. Liquid can not
be compressed and when a compressor tries
to compress a liquid, mechanical failing can
happen. The compressor can suffer
mechanical damage in the valves and
bearings. This is called” liquid slugging”.
• Normally TXV's are set to maintain 10
degrees of superheat. That means that the
gas returning to the compressor is at least 10
degrees away from the risk of having any
liquid.
10. The Evaporator
• The evaporator is where the heat is
removed from your house , business or
refrigeration box.
• Low pressure liquid leaves the metering
device and enters the evaporator.
• Usually, a fan will move warm air from
the conditioned space across the
evaporator finned coils.
• The cooler refrigerant in the evaporator
tubes, absorb the warm room air. The
change of temperature causes the
refrigerant to “flash” or “boil”, and
changes from a low pressure liquid to a
low pressure cold vapor.
• The low pressure vapor is pulled into the
compressor and the cycle starts over.
• The amount of heat added to the liquid
to make it saturated and change states is
called “Super Heat”.
• One way to charge a system with
refrigerant is by super heat.
11. Basic Refrigeration Cycle
• Starting at the compressor;
• Low pressure vapor refrigerant is compressed
and discharged out of the compressor.
• The refrigerant at this point is a high
temperature, high pressure, “superheated”
vapor.
• The high pressure refrigerant flows to the
condenser by way of the "Discharge Line".
• The condenser changes the high pressure
refrigerant from a high temperature vapor to a
low temperature, high pressure liquid and
leaves through the "Liquid Line".
• The high pressure refrigerant then flows
through a filter dryer to the Thermal Expansion
valve or TXV.
• The TXV meters the correct amount of liquid
refrigerant into the evaporator.
• As the TXV meters the refrigerant, the high
pressure liquid changes to a low pressure, low
temperature, saturated liquid/vapor.
• This saturated liquid/vapor enters the
evaporator and is changed to a low pressure,
dry vapor.
• The low pressure, dry vapor is then returned to
the compressor in the "Suction line".
• The cycle then starts over.
12. Using a P/T chart
• When you are charging or just checking a
refrigeration unit, you use a set of gauges.
The blue hose connects to a port on the low
side of the system and your red hose will
connect to the high side of the system.
• To properly know what your pressures and
temperatures should be, you will need to
know what refrigerant you are working with
and a “PressureTemperature Chart” (P/T
Chart).
• With a P/T chart, if you know a temperature
or a pressure of the ambient air or the
refrigerant in your system, you can use a
P/T chart to convert it to the equal pressure
or temperature.
• For an example using the chart at the right,
at 100°f R22 refrigerant pressure would be
198.4.
• R502 at 100° would be 218.6, R12 at 100°
would be 119.4 lb’s pressure.
• If you just know a pressure, cross the
pressure on the chart to the corresponding
temperature.
13. Charging
•A common method for checking or charging is by “head
pressure”.
•Find the units design condenser temperature from the
specifications, add 30° to the outside ambient air temperature
(70° is the outside air temp. add 30°, that gives you 100°). Take
your P/T chart and see what the pressure crosses up to at 100°
using R22.
•At 100°f R22 equals 198.4 PSI, so you would charge your
system up until you “head pressure” was close to 198.4.
•If the unit has a sight glass, check it for bubbles. If it does
have bubbles, add more refrigerant slowly until it clears
•Always charge refrigerant into the suction line as a vapor. This
is done by keeping your refrigerant cylinder right side up. If
your cylinder is on it’s side or upside down, you will be
charging liquid refrigerant and it could damage your
compressor.
•If you are charging a cap tube system, charging by “super
heat” is a good method. Check your units specifications and
pick a desired “super heat” (10° to 16°), add or subtract
refrigerant until the super heat is achieved. The superheat is
fixed at 8 to 12 degrees in most residential air conditioning
systems.
14. Sub-Cooling & Super-Heat
• Measure Sub-cooling:
• Get the refrigerant saturation pressure-temperature. Take a
pressure reading of the liquid line leaving the condenser.
Refrigerant saturation temperature is the pressure-
temperature, when the refrigerant is turning from a high-
pressure vapor into a high-pressure liquid (giving up heat). At
saturation pressure-temperature, both liquid and vapor are at
the same temperature.
• (1) Convert pressure to temperature with a P/T chart.
• (2) Take a temperature reading at the leaving liquid line of the
condenser.
• Compare both, the saturated temperature and leaving liquid
line temperature. Subtracting one from the other, the
difference is the amount the refrigerant has cooled past
saturated temperature.
• Measure Evaporator Superheat:
• Get a pressure reading of the suction line leaving the
evaporator to get refrigerant saturation pressure-temperature.
Refrigerant saturation temperature is the pressure-
temperature, when the refrigerant is turning from a low-
pressure liquid to a low-pressure vapor (absorbing heat). At
saturation pressure-temperature, both liquid and vapor are at
the same temperature.
• Convert pressure to temperature with a P/T chart. If reading is
obtained at the compressor, not at the evaporator line leaving,
you may have to add a few pounds of pressure due to
pressure drop in the suction line.
• Take a temperature reading at the leaving suction line of the
evaporator.
• Compare both, the saturated temperature and the leaving
suction line temperature. Subtracting one from the other, the
difference is the amount the refrigerant gas has heated past
saturated temperature.
15. Terms and Info
• BTU’s - An air conditioner's capacity is measured in “British Thermal Units”, or BTUs. A
BTU is the amount of heat required to raise, by one degree, the temperature of a pound of
water. So if you buy an air conditioner rated at 10,000 BTUs, it has the ability to cool 10,000
pounds -- about 1,200 gallons -- of water, one degree in an hour. Refrigeration is normally
measured in “Tons”. 12,000 BTU’s equal 1 ton.
• Latent Heat - Latent Heat is the heat given up or absorbed by a substance as it changes
state. It is called latent because it is not associated with a change in temperature. Each
substance has a characteristic latent heat of fusion, latent heat of vaporization, latent heat
of condensation and latent heat of sublimation.
• Superheated Vapor - Refrigerant vapor is heated above its saturation temperature. If a
refrigerant is superheated, there is no liquid present. Superheat is an indication of how full
the evaporator is of liquid refrigerant. High superheat means the evaporator is empty. Low
superheat means the evaporator is full.
• Saturation Temperature - Also referred to as the boiling point or the condensing
temperature. This is the temperature at which a refrigerant will change state from a liquid
to a vapor or vice versa.
• Sensible Heat - Heat, that when added or removed, causes a change in temperature but
not in state.
• Sub-Cooling - Sub-cooling is a temperature below saturated pressure-temperature. Sub-
cooling is a measurement of how much liquid is in the condenser. In air conditioning, it is
important to measure sub-cooling because the longer the liquid stays in the condenser, the
greater the sensible (visible) heat loss. Low sub-cooling means that a condenser is empty.
High sub-cooling means that a condenser is full. Over filling a system, increases pressure
due to the liquid filling of a condenser that shows up as high sub-cooling. To move the
refrigerant from condenser to the liquid line, it must be pushed down the liquid line to a
metering device. If a pressure drop occurs in the liquid line and the refrigerant has no sub-
cooling, the refrigerant will start to re-vaporize (change state from a liquid to a vapor)
before reaching the metering devise.