ClassX Video Lessons Youtube Channel The Engineering Mindset Purging Industrial Refrigeration Systems – ammonia industrial engineering
Welcome to an exploration of how intelligent purging systems work to remove non-condensable gases from industrial ammonia refrigeration systems. This article will guide you through the process, ensuring you understand the key components and their functions within the system.
In a typical single-stage industrial ammonia refrigeration system, the compressor plays a crucial role by pushing high-pressure ammonia vapor to the condenser. Here, the unwanted heat from the cooling space is removed from the refrigerant and dispersed into the atmosphere. As the heat is extracted, the ammonia refrigerant condenses into a liquid form. This high-pressure liquid then moves to the receiver and subsequently to the expansion valve.
The receiver acts as a temporary storage for the liquid refrigerant, stabilizing the system by releasing or accumulating refrigerant based on cooling demands. An equalizing line connects the receiver and the compressor discharge line, balancing the pressure between these points and allowing ammonia vapor to flow, which helps maintain the liquid refrigerant level.
The expansion valve is responsible for regulating the pressure and flow of liquid refrigerant into the evaporator circuit. From here, the ammonia enters the liquid separator, where the liquid settles at the bottom. A pump typically draws this refrigerant into the evaporator, where it absorbs unwanted heat, causing it to boil and evaporate. The ammonia then returns to the liquid separator as a liquid-vapor mixture. The liquid repeats the cycle, while the vapor is drawn into the compressor suction line, continuing the cycle.
Non-condensable gases and air tend to accumulate at two main locations in the system: the top of the receiver above the liquid refrigerant and the top of the drop leg at the condenser outlet. These gases reduce system efficiency, lowering cooling capacity and increasing energy consumption. To maintain optimal performance, purging these gases is essential.
A purging unit is connected to the locations where air and gases accumulate, with solenoid valves controlling access. Another pipe connects back to the liquid line, acting as a drain to return any ammonia collected during the filtering process.
Inside the purging unit, a smaller refrigeration system operates with a different refrigerant, R452A. This system includes a small compressor, condenser, receiver, expansion valve, and evaporator. The ammonia system and the R452A system remain separate, ensuring no mixing occurs.
The controller signals one of the solenoid valves to open, allowing the mixture of air, ammonia vapor, and non-condensable gases to enter the purging unit’s evaporator. Only one valve opens at a time to prevent flooding. The R452A refrigerant cools the gas mixture in the evaporator, causing the ammonia to condense into a liquid while the air and gases remain in gas form due to their different properties.
The liquid ammonia flows back into the system via gravity through the drain line, while the air and gases accumulate in the evaporator. Once a certain level is reached, the controller opens another solenoid valve to vent the air and gases to an external water bath, which removes any residual ammonia.
This process repeats, ensuring the system operates efficiently.
Understanding the purging process in industrial ammonia refrigeration systems is crucial for maintaining efficiency and performance. By effectively removing non-condensable gases, these systems can operate at optimal levels, reducing energy consumption and enhancing cooling capacity.
For further learning, explore additional resources and videos on this topic to deepen your understanding of industrial refrigeration systems.
Engage with a virtual simulation of an industrial ammonia refrigeration system. This activity allows you to manipulate different components, such as the compressor, condenser, and expansion valve, to see how they interact. Observe the effects of non-condensable gases on system efficiency and practice purging them to restore optimal performance.
Analyze real-world case studies of industrial refrigeration systems that experienced efficiency issues due to non-condensable gases. Discuss in groups how the purging process was implemented to resolve these issues and present your findings to the class.
Work in teams to design a purging system for a hypothetical industrial refrigeration setup. Consider the placement of solenoid valves, the choice of refrigerant for the purging unit, and the integration with the existing system. Present your design and justify your choices based on efficiency and cost-effectiveness.
Participate in a role-playing exercise where you assume the roles of different components in the refrigeration system. This activity will help you understand the flow of refrigerant and the impact of non-condensable gases. Discuss how each component contributes to the overall system efficiency and the importance of purging.
Prepare a technical presentation on the purging process, focusing on the science behind the separation of ammonia and non-condensable gases. Use diagrams and animations to illustrate the process and explain how the purging unit maintains system efficiency. This will enhance your understanding and communication skills.
Sure! Here’s a sanitized version of the transcript:
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[Paul] Hey there, everyone! Paul here from TheEngineeringMindset.com. In this video, we’re going to explore how intelligent purging systems work to extract non-condensable gases from an industrial ammonia refrigeration system. I want to take a moment to thank Danfoss for sponsoring this video. When you’re done watching, I highly recommend checking out their intelligent purging systems. Just click on the link in the video description below.
Let’s take a look at a typical single-stage industrial ammonia refrigeration system. We have the compressor, which pushes high-pressure ammonia vapor to the condenser. All the unwanted heat from the cooling space is removed from the refrigerant in the condenser, and that heat is then dispersed into the atmosphere. As the heat is removed, the ammonia refrigerant condenses and converts into a liquid. This high-pressure liquid refrigerant then flows to the receiver and into the expansion valve.
The receiver holds a quantity of liquid refrigerant in temporary storage and will release or accumulate refrigerant here to stabilize changes in the cooling demands on the system. There is an equalizing line between the receiver and the compressor discharge line, which equalizes the pressure between these two points in the system so that ammonia vapor can flow, allowing the liquid refrigerant level to vary.
The expansion valve regulates the pressure and addition of liquid refrigerant into the evaporator circuit. From the expansion valve, the ammonia flows into the liquid separator. The liquid flows to the bottom, where a pump typically draws in the refrigerant and sends it to the evaporator to provide cooling and collect unwanted heat. The ammonia picks up the unwanted heat from the evaporator, causing it to boil and evaporate. It leaves the evaporator and enters back into the liquid separator as a liquid-vapor mixture. The liquid refrigerant falls down and repeats the cycle, while the vapor rises and is drawn into the compressor suction line. This low-pressure vapor refrigerant is then compressed and sent around the system in a continuous cycle.
Now, in this system, we will get a buildup of non-condensable gases and air in two main locations: at the top of the receiver above the liquid refrigerant and at the top of the drop leg of the outlet of the condenser. These gases and pockets of air will decrease the system’s efficiency, reducing cooling capacity and increasing energy consumption. It is inevitable that air will get into the system, so we need to purge this to maintain optimal performance.
We connect a purging unit to both locations where the air and gases accumulate and control access to these with solenoid valves. We also have another pipe connected back to the liquid line, which acts as a drain to return any ammonia collected during the filtering process.
Let’s take a look inside the purging unit to see how it operates. Inside the purging unit, we have a smaller refrigeration system with a small compressor pushing a different refrigerant, in this case, R452A. This refrigerant flows to a small condenser with its own fan, which blows ambient air across the heat exchanger. The refrigerant then flows to a receiver, then to an expansion valve, and into an evaporator, returning to the compressor.
The evaporator is connected to the ammonia system, but the two systems are completely separate. The ammonia and R452A never meet or mix. The controller signals for one of the solenoid valves to open, venting the mixture of air, ammonia, and non-condensable gases into the evaporator within the purging unit. Only one valve can open at a time to prevent flooding the unit.
With one of the solenoid valves open, for example, the receiver tank valve, the mixture of air, ammonia vapor, and other gases will seep out of the receiver tank and into the evaporator of the purging unit. These vapors and gases will build up in the evaporator. The small refrigeration system cycles the R452A refrigerant on the other side of the evaporator, providing cooling to the gas mixture.
The mixture will be cooled below the condensing temperature of the ammonia, causing just the ammonia to condense into a liquid. The air and gases will remain in gas form due to their different properties and lower condensing temperatures. The air and gases will remain in the evaporator while the ammonia turns into a liquid, which will then flow back via gravity into the system through the drain line.
As this occurs, it naturally draws in more air, ammonia, and vapor gas mixtures. This continues until the buildup of air and gases in the evaporator reaches a certain level. The controller detects the change in evaporator temperature and pressure due to the buildup and opens another solenoid valve on the vent line from the evaporator to discharge the buildup of air and gases. This allows the air and gases to flow away to an external water bath, which washes out any residual ammonia.
The process then repeats, maintaining the system at optimal performance.
Okay, everyone, that’s it for this video! To continue your learning, check out one of the videos on screen now, and I’ll catch you there for the next lesson. Don’t forget to follow us on social media and visit TheEngineeringMindset.com.
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Purging – The process of removing unwanted gases or vapors from a system to ensure its proper functioning and safety. – In HVAC systems, purging is essential to eliminate air pockets that can hinder the system’s efficiency.
Refrigeration – The process of removing heat from a space or substance to lower its temperature, often used in cooling systems. – The refrigeration cycle is fundamental in air conditioning systems to maintain desired indoor climates.
Ammonia – A colorless gas with a pungent smell, used as a refrigerant in industrial refrigeration systems due to its high efficiency and low environmental impact. – Ammonia is favored in large-scale refrigeration systems because it offers excellent thermodynamic properties.
Compressor – A mechanical device that increases the pressure of a gas by reducing its volume, crucial in refrigeration and air conditioning systems. – The compressor is the heart of the refrigeration cycle, responsible for circulating the refrigerant through the system.
Evaporator – A component in a refrigeration system where the refrigerant absorbs heat and evaporates, thus cooling the surrounding area. – The efficiency of an evaporator directly affects the overall cooling capacity of the refrigeration system.
Gases – Substances in a state of matter characterized by low density and viscosity, which can expand freely to fill any space available. – Understanding the behavior of gases under different conditions is crucial for designing efficient HVAC systems.
Efficiency – The ratio of useful output to total input in any system, often used to measure the performance of machines and processes. – Improving the efficiency of a heat engine can significantly reduce energy consumption and operational costs.
Condenser – A device used in refrigeration systems to condense refrigerant vapor into liquid by removing heat, typically through air or water cooling. – The condenser plays a vital role in dissipating heat from the refrigeration cycle to the environment.
Expansion – The process of increasing the volume of a gas or liquid, often resulting in a decrease in temperature, as seen in refrigeration cycles. – The expansion valve controls the flow of refrigerant into the evaporator, allowing for efficient cooling.
Performance – The ability of a system or component to function effectively under specified conditions, often evaluated through metrics like efficiency and capacity. – Regular maintenance is crucial to ensure the optimal performance of engineering systems.
