The document discusses enhancing the performance of vapor compression refrigeration systems (VCRS) using a liquid suction heat exchanger (LSHX). Adding an LSHX between the condenser and evaporator allows for subcooling of the liquid refrigerant and superheating of the vapor. This increases the refrigeration effect and coefficient of performance (COP) of the system. Theoretically, the COP of a VCRS with an LSHX is higher than a simple cycle without subcooling or superheating. Previous studies have also found improvements to COP of up to 18% with the addition of an LSHX. The document analyzes the vapor compression cycle both on T-S and P-h diagrams to
This document summarizes research on modifications to vapor compression refrigeration systems to improve efficiency. It discusses using a diffuser at the condenser inlet to reduce the velocity of refrigerant leaving the compressor, which can improve system performance. The document reviews several other modifications studied in literature, including advances in compressor design, increasing subcooling, minimizing evaporator hunting, and new refrigerant cycles. It concludes that reducing refrigerant velocity with a diffuser can avoid problems caused by high velocity such as liquid humping and damage to condenser tubing.
Different Types of heat pump water heaters, technological advancements and efficiency changes in each type with their advantages / disadvantages and future prospects.
The document discusses improvements that can be made to the vapor compression refrigeration cycle. It describes how increasing sub-cooling and superheating of the refrigerant can improve the system's coefficient of performance and cooling capacity. Various techniques for sub-cooling and recovering expansion losses such as suction line heat exchangers, expanders, and ejectors are also summarized. The document also reviews natural refrigerants like air, water, hydrocarbons, ammonia, and carbon dioxide and assesses their properties and applications in refrigeration systems.
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 experimentally investigates enhancing the performance of a domestic refrigerator by adding a shell and tube heat exchanger after the condenser. Ammonia is used as the cooling fluid in the heat exchanger to further subcool the refrigerant. Testing showed the coefficient of performance increased 18.4% with the additional heat exchanger due to increased refrigeration effect and lower operating pressures and temperatures. Graphs compare the heat rejection, refrigeration effect, power input, and COP between the original and modified systems.
Refrigeration is the process of lowering and maintaining a substance's temperature below the ambient temperature. Refrigerants are working fluids that absorb heat in the evaporator and release it in the condenser while undergoing phase changes between liquid and gas. The two main types of refrigeration systems are vapor compression, which uses mechanical energy to circulate refrigerant, and vapor absorption, which is heat-powered. Vapor compression is more common due to lower maintenance costs, while absorption systems have higher capacities and more consistent efficiency at partial loads.
The document discusses enhancing the performance of vapor compression refrigeration systems (VCRS) using a liquid suction heat exchanger (LSHX). Adding an LSHX between the condenser and evaporator allows for subcooling of the liquid refrigerant and superheating of the vapor. This increases the refrigeration effect and coefficient of performance (COP) of the system. Theoretically, the COP of a VCRS with an LSHX is higher than a simple cycle without subcooling or superheating. Previous studies have also found improvements to COP of up to 18% with the addition of an LSHX. The document analyzes the vapor compression cycle both on T-S and P-h diagrams to
This document summarizes research on modifications to vapor compression refrigeration systems to improve efficiency. It discusses using a diffuser at the condenser inlet to reduce the velocity of refrigerant leaving the compressor, which can improve system performance. The document reviews several other modifications studied in literature, including advances in compressor design, increasing subcooling, minimizing evaporator hunting, and new refrigerant cycles. It concludes that reducing refrigerant velocity with a diffuser can avoid problems caused by high velocity such as liquid humping and damage to condenser tubing.
Different Types of heat pump water heaters, technological advancements and efficiency changes in each type with their advantages / disadvantages and future prospects.
The document discusses improvements that can be made to the vapor compression refrigeration cycle. It describes how increasing sub-cooling and superheating of the refrigerant can improve the system's coefficient of performance and cooling capacity. Various techniques for sub-cooling and recovering expansion losses such as suction line heat exchangers, expanders, and ejectors are also summarized. The document also reviews natural refrigerants like air, water, hydrocarbons, ammonia, and carbon dioxide and assesses their properties and applications in refrigeration systems.
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 experimentally investigates enhancing the performance of a domestic refrigerator by adding a shell and tube heat exchanger after the condenser. Ammonia is used as the cooling fluid in the heat exchanger to further subcool the refrigerant. Testing showed the coefficient of performance increased 18.4% with the additional heat exchanger due to increased refrigeration effect and lower operating pressures and temperatures. Graphs compare the heat rejection, refrigeration effect, power input, and COP between the original and modified systems.
Refrigeration is the process of lowering and maintaining a substance's temperature below the ambient temperature. Refrigerants are working fluids that absorb heat in the evaporator and release it in the condenser while undergoing phase changes between liquid and gas. The two main types of refrigeration systems are vapor compression, which uses mechanical energy to circulate refrigerant, and vapor absorption, which is heat-powered. Vapor compression is more common due to lower maintenance costs, while absorption systems have higher capacities and more consistent efficiency at partial loads.
an experiment on a co2 air conditioning system with copper heat exchangersINFOGAIN PUBLICATION
This document presents an experiment on a CO2 air conditioning system using copper heat exchangers. Testing showed that a conventional compressor is not suitable for high CO2 pressures and achieved a low COP of 0.3. A CO2 compressor allowed the system to run as a saturated cycle, achieving a COP of 3.07 at an evaporator temperature of 10°C, comparable to commercial systems. Thermodynamic parameters were measured and the cycle was shown to follow refrigeration principles, though pressure drops meant processes were quasi-isothermal and isobaric.
This document analyzes the performance of a regenerative steam system in a thermal power plant and proposes modifications to improve turbine efficiency. Currently, cascading only occurs between high pressure and low pressure heaters separately, wasting heat to the deaerator. The proposal involves cascading all heaters together to utilize waste heat in low pressure heaters. Taking extraction steam at the high pressure turbine outlet instead of the boiler outlet could also increase turbine work and efficiency. Analysis estimates increasing heater coils could lower drip temperatures enough for cascading, recovering over 29,000 kW of heat annually and raising plant efficiency by 3%.
WORKING OF HEAT PUMPS WITH (CO2) REFRIGERANT Swathi Rampur
The document discusses heat pumps, which transfer heat from one place to another against a temperature gradient using external energy. It describes the typical components of a heat pump - evaporator, compressor, condenser, expansion valve - and how they work together in the heating and cooling cycles. Carbon dioxide is highlighted as a natural, non-toxic refrigerant with advantages over traditional refrigerants like Freon, though it requires higher operating pressures. The document concludes that heat pumps using carbon dioxide as the refrigerant can provide efficient and environmentally friendly heating and cooling.
This document describes tests of a refrigeration system that uses flooded evaporation in the evaporator. Key aspects of the new system include a bubble expansion valve to control liquid flow, an ejector pump to circulate refrigerant, and a method to recover pressure drop losses. Testing showed the new system improved evaporator temperature by 3.5K and reduced power consumption by 10% compared to a standard direct expansion system. Operating data and test results are presented, showing the flooded evaporator system significantly improved heat exchanger efficiency.
Reheating Refrigeration System to control and utilize the rejected heat from an air conditioner to reduce the input power of the compressor without affecting the cooling effect.
The document presents a computer model for assessing the effect of suction-line heat exchangers (SLHXs) on the performance of alternative refrigerants to R-22. The model is validated by comparing its results to previous analyses that used REFPROP and CoolPack software. The model is then used to analyze the performance of six refrigerants - R-134a, R-152a, R-407C, R-410A, R-290, and R-600a - at different subcooling degrees from 2 to 10°C. The results show that R-152a, R-407C, and R-600a are suitable alternatives to R-22.
This document discusses multi-pressure refrigeration systems. It explains that single-stage systems have limitations at very low evaporator or high condenser temperatures due to increased losses. Multi-stage systems address this by using multiple compression stages to reduce the temperature lift in each stage. Types of multi-stage systems include multi-compression, multi-evaporator, and cascade systems. Flash gas removal and intercooling can further improve the performance of multi-stage systems. Cascade systems use multiple refrigerants matched to different temperature ranges.
K10854 Experimental evaluation of cascade refrigeration plantShraddhey Bhandari
The document summarizes several experiments on cascade refrigeration systems using different refrigerant pairs. The first experiment evaluated a CO2 and NH3 system for freezing applications, finding the optimum CO2 condensing temperature was within 2.4% of published correlations. A second experiment analyzed a R134a and CO2 system, determining compressor performance, temperatures, cooling capacity, and COPs of the individual and overall systems. A third experiment used an R22/R404A pair to determine the optimal condensing temperature of the low-temperature circuit by evaluating the individual and global COPs.
The document analyzes the performance of an 80-ton capacity air-cooled scroll chiller system using R-22 and R-407C refrigerants. Experimental results show the theoretical COP of R-22 is 4.166 but the actual COP is 2.227, while for R-407C the theoretical COP is 3.465 and actual COP is higher at 2.745. Based on these results, R-407C is concluded to be a viable alternative refrigerant to R-22 for air-cooled chilling systems and HVAC applications.
Experimental Investigation of a Household Refrigerator Using Evaporative-Cool...inventy
The objective of this paper was to investigate experimentally the effect of Evaporative-cooled condenser in a household refrigerator. The experiment was done using HCF134a as the refrigerant. The performance of the household refrigerator with air-cooled and Evaporative-cooled condenser was compared for different load conditions. The results indicate that the refrigerator performance had improved when evaporative-cooled condenser was used instead of air-cooled condenser on all load conditions. Evaporativecooled condenser reduced the energy consumption when compared with the air-cooled condenser. There was also an enhancement in coefficient of performance (COP) when evaporative-cooled condenser was used instead of air-cooled condenser. The Evaporative cooled heat exchanger was designed and the system was modified by retrofitting it, instead of the conventional air-cooled condenser by making drop wise condensation using water and forced circulation over the condenser. From the experimental analysis it is observed that the COP of evaporative cooled system increased by 13.44% compared to that of air cooled system. So the overall efficiency and refrigerating effect is increased. In minimum constructional, maintenance and running cost, the system is much useful for domestic purpose. This study also revealed that combining a evaporative cooled system along with conventional water cooled system under the condition that the defrost water obtained from the freezer is used for drop wise condensation over condenser and water cooled condensation of the condenser at the bottom using remaining defrost water would reduce the power consumption, work done and hence further increase in refrigerating effect of the system. The study has shown that such a system is technically feasible and economically viable
The document discusses the basic processes of a vapor compression refrigeration cycle including: evaporation of refrigerant absorbing heat from the refrigerated space; compression of the vapor requiring work input; condensation of the vapor releasing heat to the surroundings; and expansion of the liquid refrigerant. It also discusses engineering models and assumptions made in analyzing the cycle components, refrigeration capacity, coefficient of performance, use of pressure-enthalpy diagrams, multistage compression systems, flash gas removal, cascade systems, and psychrometric processes.
Review of Modified Vapor Absorption Refrigeration CyclesIRJET Journal
This document reviews various modifications made to vapor absorption refrigeration cycles to improve their performance. It discusses cycles that use an ejector, generator-absorber heat exchanger, booster compressor, or multiple absorption stages. The ejector cycle is found to have a 30% higher COP than a single-effect cycle. Generator-absorber heat exchanger cycles like the hybrid GAX cycle can achieve a COP as high as 0.98. A cycle with a booster compressor between the evaporator and absorber reaches a maximum COP of 0.645. The triple effect cycle demonstrates up to 132% higher COP than a single effect cycle. In general, modified cycles offer benefits like reduced losses, increased performance, and decreased energy consumption
This document discusses air conditioning processes and psychrometrics. It defines key terms like dry bulb temperature, wet bulb temperature, dew point temperature, relative humidity, specific volume, and specific enthalpy as they relate to moist air. It also describes the adiabatic saturation process, where unsaturated air is blown over a water spray, causing it to become saturated at a constant wet bulb temperature. Key psychrometric concepts like humidity ratio and degree of saturation are also introduced.
The document describes a water cooling system that uses engine exhaust heat from a two-wheeler engine. The system uses an adsorber bed filled with activated carbon to adsorb R134a refrigerant. Exhaust from the engine passes through the adsorber bed, heating it and causing the refrigerant to evaporate. The evaporated refrigerant then passes through a coil that acts as an evaporator, cooling water passed through it. After condensing, the refrigerant is expanded through a valve and re-adsorbed in the bed, completing the cycle. Experimental results showed the system could cool 2 liters of water to 19°C within 30 minutes, using only waste heat from the engine exhaust. The system provides
ENERGY AUDIT presentationin power system .pptxReshevSharma
An energy audit is a systematic process of evaluating and analyzing energy usage in a building, facility, or industrial process to identify opportunities for energy efficiency improvements, cost savings, and environmental sustainability. The goal of an energy audit is to assess energy consumption patterns, identify areas of inefficiency or waste, and recommend measures to optimize energy usage and reduce overall energy consumption.
Here's an overview of the typical steps involved in conducting an energy audit:
1. **Pre-Audit Planning:**
Define the scope and objectives of the energy audit, including the areas or systems to be evaluated, the level of detail required, and the desired outcomes. Identify key stakeholders, establish audit goals, and gather relevant documentation, such as utility bills, building plans, and equipment specifications.
2. **Data Collection and Analysis:**
Collect comprehensive data on energy consumption, including utility bills, meter readings, and operational data
Improving and Comparing the Coefficient of Performance of Domestic Refgirator...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This document discusses refrigeration, chilling, and freezing processes used to preserve food. It describes the basic refrigeration cycle of evaporation, compression, condensation, and expansion. Low temperatures slow microbial growth and chemical reactions in food, allowing longer storage. Freezing stops microbial growth. The document provides examples calculating refrigeration system requirements and performance based on thermodynamic property charts. It discusses factors like evaporator and condenser temperatures, refrigerant selection, and their impacts on system design and efficiency.
This document discusses vapor compression refrigeration systems from Sana'a University in Yemen. It covers topics like coefficient of performance, the basic refrigeration cycle with four main components (evaporator, compressor, condenser, expansion valve), processes within the cycle, effects of evaporator and condenser temperatures, examples of cycle analysis, use of flash tanks and accumulators, and multistage compression systems. The document is presented by Dr. Abduljalil Al-Abidi from the Mechanical Engineering department and focuses on vapor compression refrigeration taught to students.
The document discusses performance aspects and modifications that can be made to standard vapour compression refrigeration systems (VCRS). It describes how the specific and volumetric refrigeration effects and coefficient of performance (COP) are affected by evaporator and condenser temperatures in a standard VCRS cycle. Common modifications like subcooling of liquid refrigerant and superheating of vapour refrigerant are explained. Subcooling reduces throttling losses and increases refrigeration effect. Superheating may or may not increase COP depending on the refrigerant, but prevents liquid droplets entering the compressor. A liquid-suction heat exchanger can provide necessary subcooling and superheating without heat exchange with external sources.
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.
an experiment on a co2 air conditioning system with copper heat exchangersINFOGAIN PUBLICATION
This document presents an experiment on a CO2 air conditioning system using copper heat exchangers. Testing showed that a conventional compressor is not suitable for high CO2 pressures and achieved a low COP of 0.3. A CO2 compressor allowed the system to run as a saturated cycle, achieving a COP of 3.07 at an evaporator temperature of 10°C, comparable to commercial systems. Thermodynamic parameters were measured and the cycle was shown to follow refrigeration principles, though pressure drops meant processes were quasi-isothermal and isobaric.
This document analyzes the performance of a regenerative steam system in a thermal power plant and proposes modifications to improve turbine efficiency. Currently, cascading only occurs between high pressure and low pressure heaters separately, wasting heat to the deaerator. The proposal involves cascading all heaters together to utilize waste heat in low pressure heaters. Taking extraction steam at the high pressure turbine outlet instead of the boiler outlet could also increase turbine work and efficiency. Analysis estimates increasing heater coils could lower drip temperatures enough for cascading, recovering over 29,000 kW of heat annually and raising plant efficiency by 3%.
WORKING OF HEAT PUMPS WITH (CO2) REFRIGERANT Swathi Rampur
The document discusses heat pumps, which transfer heat from one place to another against a temperature gradient using external energy. It describes the typical components of a heat pump - evaporator, compressor, condenser, expansion valve - and how they work together in the heating and cooling cycles. Carbon dioxide is highlighted as a natural, non-toxic refrigerant with advantages over traditional refrigerants like Freon, though it requires higher operating pressures. The document concludes that heat pumps using carbon dioxide as the refrigerant can provide efficient and environmentally friendly heating and cooling.
This document describes tests of a refrigeration system that uses flooded evaporation in the evaporator. Key aspects of the new system include a bubble expansion valve to control liquid flow, an ejector pump to circulate refrigerant, and a method to recover pressure drop losses. Testing showed the new system improved evaporator temperature by 3.5K and reduced power consumption by 10% compared to a standard direct expansion system. Operating data and test results are presented, showing the flooded evaporator system significantly improved heat exchanger efficiency.
Reheating Refrigeration System to control and utilize the rejected heat from an air conditioner to reduce the input power of the compressor without affecting the cooling effect.
The document presents a computer model for assessing the effect of suction-line heat exchangers (SLHXs) on the performance of alternative refrigerants to R-22. The model is validated by comparing its results to previous analyses that used REFPROP and CoolPack software. The model is then used to analyze the performance of six refrigerants - R-134a, R-152a, R-407C, R-410A, R-290, and R-600a - at different subcooling degrees from 2 to 10°C. The results show that R-152a, R-407C, and R-600a are suitable alternatives to R-22.
This document discusses multi-pressure refrigeration systems. It explains that single-stage systems have limitations at very low evaporator or high condenser temperatures due to increased losses. Multi-stage systems address this by using multiple compression stages to reduce the temperature lift in each stage. Types of multi-stage systems include multi-compression, multi-evaporator, and cascade systems. Flash gas removal and intercooling can further improve the performance of multi-stage systems. Cascade systems use multiple refrigerants matched to different temperature ranges.
K10854 Experimental evaluation of cascade refrigeration plantShraddhey Bhandari
The document summarizes several experiments on cascade refrigeration systems using different refrigerant pairs. The first experiment evaluated a CO2 and NH3 system for freezing applications, finding the optimum CO2 condensing temperature was within 2.4% of published correlations. A second experiment analyzed a R134a and CO2 system, determining compressor performance, temperatures, cooling capacity, and COPs of the individual and overall systems. A third experiment used an R22/R404A pair to determine the optimal condensing temperature of the low-temperature circuit by evaluating the individual and global COPs.
The document analyzes the performance of an 80-ton capacity air-cooled scroll chiller system using R-22 and R-407C refrigerants. Experimental results show the theoretical COP of R-22 is 4.166 but the actual COP is 2.227, while for R-407C the theoretical COP is 3.465 and actual COP is higher at 2.745. Based on these results, R-407C is concluded to be a viable alternative refrigerant to R-22 for air-cooled chilling systems and HVAC applications.
Experimental Investigation of a Household Refrigerator Using Evaporative-Cool...inventy
The objective of this paper was to investigate experimentally the effect of Evaporative-cooled condenser in a household refrigerator. The experiment was done using HCF134a as the refrigerant. The performance of the household refrigerator with air-cooled and Evaporative-cooled condenser was compared for different load conditions. The results indicate that the refrigerator performance had improved when evaporative-cooled condenser was used instead of air-cooled condenser on all load conditions. Evaporativecooled condenser reduced the energy consumption when compared with the air-cooled condenser. There was also an enhancement in coefficient of performance (COP) when evaporative-cooled condenser was used instead of air-cooled condenser. The Evaporative cooled heat exchanger was designed and the system was modified by retrofitting it, instead of the conventional air-cooled condenser by making drop wise condensation using water and forced circulation over the condenser. From the experimental analysis it is observed that the COP of evaporative cooled system increased by 13.44% compared to that of air cooled system. So the overall efficiency and refrigerating effect is increased. In minimum constructional, maintenance and running cost, the system is much useful for domestic purpose. This study also revealed that combining a evaporative cooled system along with conventional water cooled system under the condition that the defrost water obtained from the freezer is used for drop wise condensation over condenser and water cooled condensation of the condenser at the bottom using remaining defrost water would reduce the power consumption, work done and hence further increase in refrigerating effect of the system. The study has shown that such a system is technically feasible and economically viable
The document discusses the basic processes of a vapor compression refrigeration cycle including: evaporation of refrigerant absorbing heat from the refrigerated space; compression of the vapor requiring work input; condensation of the vapor releasing heat to the surroundings; and expansion of the liquid refrigerant. It also discusses engineering models and assumptions made in analyzing the cycle components, refrigeration capacity, coefficient of performance, use of pressure-enthalpy diagrams, multistage compression systems, flash gas removal, cascade systems, and psychrometric processes.
Review of Modified Vapor Absorption Refrigeration CyclesIRJET Journal
This document reviews various modifications made to vapor absorption refrigeration cycles to improve their performance. It discusses cycles that use an ejector, generator-absorber heat exchanger, booster compressor, or multiple absorption stages. The ejector cycle is found to have a 30% higher COP than a single-effect cycle. Generator-absorber heat exchanger cycles like the hybrid GAX cycle can achieve a COP as high as 0.98. A cycle with a booster compressor between the evaporator and absorber reaches a maximum COP of 0.645. The triple effect cycle demonstrates up to 132% higher COP than a single effect cycle. In general, modified cycles offer benefits like reduced losses, increased performance, and decreased energy consumption
This document discusses air conditioning processes and psychrometrics. It defines key terms like dry bulb temperature, wet bulb temperature, dew point temperature, relative humidity, specific volume, and specific enthalpy as they relate to moist air. It also describes the adiabatic saturation process, where unsaturated air is blown over a water spray, causing it to become saturated at a constant wet bulb temperature. Key psychrometric concepts like humidity ratio and degree of saturation are also introduced.
The document describes a water cooling system that uses engine exhaust heat from a two-wheeler engine. The system uses an adsorber bed filled with activated carbon to adsorb R134a refrigerant. Exhaust from the engine passes through the adsorber bed, heating it and causing the refrigerant to evaporate. The evaporated refrigerant then passes through a coil that acts as an evaporator, cooling water passed through it. After condensing, the refrigerant is expanded through a valve and re-adsorbed in the bed, completing the cycle. Experimental results showed the system could cool 2 liters of water to 19°C within 30 minutes, using only waste heat from the engine exhaust. The system provides
ENERGY AUDIT presentationin power system .pptxReshevSharma
An energy audit is a systematic process of evaluating and analyzing energy usage in a building, facility, or industrial process to identify opportunities for energy efficiency improvements, cost savings, and environmental sustainability. The goal of an energy audit is to assess energy consumption patterns, identify areas of inefficiency or waste, and recommend measures to optimize energy usage and reduce overall energy consumption.
Here's an overview of the typical steps involved in conducting an energy audit:
1. **Pre-Audit Planning:**
Define the scope and objectives of the energy audit, including the areas or systems to be evaluated, the level of detail required, and the desired outcomes. Identify key stakeholders, establish audit goals, and gather relevant documentation, such as utility bills, building plans, and equipment specifications.
2. **Data Collection and Analysis:**
Collect comprehensive data on energy consumption, including utility bills, meter readings, and operational data
Improving and Comparing the Coefficient of Performance of Domestic Refgirator...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This document discusses refrigeration, chilling, and freezing processes used to preserve food. It describes the basic refrigeration cycle of evaporation, compression, condensation, and expansion. Low temperatures slow microbial growth and chemical reactions in food, allowing longer storage. Freezing stops microbial growth. The document provides examples calculating refrigeration system requirements and performance based on thermodynamic property charts. It discusses factors like evaporator and condenser temperatures, refrigerant selection, and their impacts on system design and efficiency.
This document discusses vapor compression refrigeration systems from Sana'a University in Yemen. It covers topics like coefficient of performance, the basic refrigeration cycle with four main components (evaporator, compressor, condenser, expansion valve), processes within the cycle, effects of evaporator and condenser temperatures, examples of cycle analysis, use of flash tanks and accumulators, and multistage compression systems. The document is presented by Dr. Abduljalil Al-Abidi from the Mechanical Engineering department and focuses on vapor compression refrigeration taught to students.
The document discusses performance aspects and modifications that can be made to standard vapour compression refrigeration systems (VCRS). It describes how the specific and volumetric refrigeration effects and coefficient of performance (COP) are affected by evaporator and condenser temperatures in a standard VCRS cycle. Common modifications like subcooling of liquid refrigerant and superheating of vapour refrigerant are explained. Subcooling reduces throttling losses and increases refrigeration effect. Superheating may or may not increase COP depending on the refrigerant, but prevents liquid droplets entering the compressor. A liquid-suction heat exchanger can provide necessary subcooling and superheating without heat exchange with external sources.
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.
Similar to CASE-STUDY-OF-LIQUID-SUCTION-HEAT-EXCHANGER-IN.pptx (20)
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
A Visual Guide to 1 Samuel | A Tale of Two HeartsSteve Thomason
These slides walk through the story of 1 Samuel. Samuel is the last judge of Israel. The people reject God and want a king. Saul is anointed as the first king, but he is not a good king. David, the shepherd boy is anointed and Saul is envious of him. David shows honor while Saul continues to self destruct.
How to Manage Reception Report in Odoo 17Celine George
A business may deal with both sales and purchases occasionally. They buy things from vendors and then sell them to their customers. Such dealings can be confusing at times. Because multiple clients may inquire about the same product at the same time, after purchasing those products, customers must be assigned to them. Odoo has a tool called Reception Report that can be used to complete this assignment. By enabling this, a reception report comes automatically after confirming a receipt, from which we can assign products to orders.
How to Download & Install Module From the Odoo App Store in Odoo 17Celine George
Custom modules offer the flexibility to extend Odoo's capabilities, address unique requirements, and optimize workflows to align seamlessly with your organization's processes. By leveraging custom modules, businesses can unlock greater efficiency, productivity, and innovation, empowering them to stay competitive in today's dynamic market landscape. In this tutorial, we'll guide you step by step on how to easily download and install modules from the Odoo App Store.
1. CASE STUDY OF LIQUID SUCTION
HEAT EXCHANGER IN MECHANICAL
REFRIGERATION SYSTEM USING
ALTERNATIVE REFRIGERANTS.
PRESENTED BY: COORDINATED BY:
Samir Ghorasainee Keshav Acharya
Sampanna Dhakal Teaching Assistant
Sanam Sapkota Purwanchal Campus,
Sanchita Sapkota Dharan
2. Mechanical Refrigeration System
Mechanical refrigeration, often referred to as refrigeration or air
conditioning, is a process by which heat is removed from a location
using a human-made heat exchange system.
As the refrigerant circulates through the system, it is alternately
compressed and expanded, changing its state from a liquid to a
vapor.
3. Components of
Refrigeration Cycle
Evaporator : It absorbs heat from
refrigerating space.
Compressor : It increases the pressure
and temperature of refrigerant through
compression.
Condenser : It releases the heat into
surrounding.
Expansion Valve : It decreases the
pressure of the refrigerant.
4. Modification of the System
Many studies have been done to
modify and enhance the performance
and energy consumption of the
mechanical refrigeration system.
Using heat exchanger in the mechanical
refrigeration system is one of the
effective technique that can be used to
improve the energy performance of the
system.
A LSHX is a counterflow heat
exchanger in which the warm
refrigerant liquid from the condenser
exchanges heat with the cool refrigerant
vapor from the evaporator.
5. Modification of the System
Refrigerant type can also influence the
system performance, so it is a big
challenge to obtain matching between the
system modification and refrigerant type.
The performances of the alternative
refrigerants R600a, R134a and R22 while
using liquid suction heat exchanger are
studied.
R600a R22
R134a
6. Model Development
The liquid-suction heat exchanger is installed across the suction and
liquid lines.
7. Model Development
The Liquid Suction Heat Exchanger allows:
Subcooling for the condensed refrigerant.
Reducing the flash gas in the liquid line to ensure maximum capacity for the
thermostatic expansion valve.
Superheating liquid of refrigerant which is located in the suction line.
Prevention of liquid refrigerant entering the reciprocating compressor.
9. Thermodynamics Analysis of Subcooling
Subcooling reduces the flash gas in the liquid line to ensure maximum capacity for the
thermostatic expansion valve, which eventually increases the refrigeration effect.
It increases the amount of heat rejection from the condenser.
It also increases the enthalpy of refrigerant entering the evaporator from 4 to 4’ , which
increases the refrigeration effect.
The work to be done in the Compressor remains unchanged.
Since subcooling increases the refrigeration effect without changing the compressor input,
COP of the system can be increased significantly.
10. Thermodynamics Analysis of Subcooling
Increases Refrigeration effect
Doesn’t change the work input
More refrigeration with same work
input
11. Thermodynamic Analysis for Superheating
Superheating saves compressor from damage by preventing refrigerant liquid
droplets that may be flown with the gas from entering the suction line.
If superheating of refrigerant takes place due to heat transfer with the refrigerated
space then it is called as useful superheating as it increases the refrigeration effect.
On the other hand, it is possible for the refrigerant vapor to become superheated
by exchanging heat with the surroundings as it flows through the connecting
pipelines, which is called as useless superheating.
12. Thermodynamic Analysis for Superheating
Fig: P-h diagram of superheating Fig: T-s diagram of superheating
13. Thermodynamic Analysis for Superheating
Superheating increases the refrigeration effect of the system.
It also increases the work to be supplied to the compressor.
Thus, although increasing the refrigeration effect of the system it may
or may not increase the COP.
The change in COP depends upon the refrigerant used.
14. Results & Conclusion
Multiple simulations were run for wide range of conditions.
Refrigerants R600a, R134a and R22 were used in the system.
Two systems : Non-Modified and Modified with LSHX were examined.
All the results were obtained through Engineering Equation Solver.
15. Effects of Subcooling
The liquid-suction heat exchanger
improves the sub-cooling for three
types of refrigerants; R22, R134a and
R600a.
However, higher value of the sub-cool
temperature was achieved by R600a.
Fig : Effect of Liquid-Suction Heat Exchanger on Superheating at
Different Condenser Pressure and Different Refrigerants
16. Effects of Superheating
The LSHX effectively increased the
superheat temperature in the suction
line.
The figure also shows that the higher
value of the super heat temperature
was achieved by R600a and achieved
better performance. Fig : Effect of Liquid-Suction Heat Exchanger on Superheating
at Different Condenser Pressure and Different Refrigerants
17. Comparison between non-modified and
modified system
Non-Modified System Modified system
The following comparison shows the refrigerant effect at different Condenser pressure
and different refrigerants :
18. Comparison between non-modified and
modified system
Non-Modified System
R600a achieved highest value of
refrigerant effect
Refrigerant Effect: about 250kJ/kg
when the condenser pressure was
350 kPa
Modified System
R600a achieved highest value of
refrigerant effect
Refrigeration Effect: about 350
kJ/kg when the condenser
pressure was 350 kPa
20. Result & Conclusion
The Figure shows that the highest value of COP was achieved by the modified
system using R134a.
Which is about 7% and 12% higher than that of R600a and R22 respectively.
The COP can be improved and enhanced up to 20% based on the refrigerant type
and operating conditions while using LSHX.
The R600a is good replacement for other refrigerants but it has lower COP
compared with R134a due to its thermodynamic properties.
21. Acknowledgement
We thank Raid Ahmed Mahmood, School of Mechanical and
Electrical Engineering, University of Southern Queensland,
Australia for the research.
22. We thank you all for your time and coordination.