ClassX Video Lessons Youtube Channel The Engineering Mindset How a boiler, fan coil unit, air handling unit and pump work together HVAC – Heating System ????????????
Welcome to an exploration of modern heating systems in commercial buildings. These systems are crucial for maintaining comfortable indoor environments, especially in large structures. Let’s dive into how components like boilers, fan coil units, air handling units, and pumps work together to create an efficient heating system.
At the heart of the heating system are the boilers. In many modern commercial buildings, you’ll find two large boilers connected in parallel. This setup allows for flexibility; both boilers can operate simultaneously, or one can be shut down for maintenance while the other continues to provide heat. This parallel configuration is preferred over a series setup for its practicality in large buildings.
Boilers serve as the primary heat source, heating water that circulates through the system. In newer constructions, boilers are often smaller and more efficient, adapting to the building’s heating demands. Brands like Hoval are well-known for their reliable commercial boilers.
The heating system is divided into primary and secondary circuits. The primary circuit includes the main pumps that circulate hot water from the boilers. These pumps push the heated water through a network of pipes, eventually reaching a component known as the low loss header.
The low loss header acts as a junction, allowing water to either continue circulating or return to the boilers for reheating. This component ensures efficient heat distribution and temperature regulation throughout the system.
From the low loss header, the system branches into secondary circuits. Each circuit serves a specific purpose:
To maintain system efficiency and safety, several components are in place:
Understanding the interplay between these components helps in appreciating the complexity and efficiency of modern HVAC heating systems. By ensuring each part functions correctly, these systems provide reliable and consistent heating, crucial for the comfort and operation of commercial buildings.
Thank you for exploring this topic with us. We hope this article has enhanced your understanding of HVAC systems. Feel free to share this knowledge with others who might find it useful!
Create a detailed diagram of a modern HVAC heating system using a digital tool like Lucidchart or Microsoft Visio. Include all key components such as boilers, primary and secondary circuits, fan coil units, and air handling units. Use color-coding to represent different temperature zones. This will help you visualize the system’s structure and function.
Analyze a case study of a commercial building that recently upgraded its HVAC system. Identify the changes made, focusing on the integration of modern boilers and the configuration of primary and secondary circuits. Discuss the impact on energy efficiency and heating performance. This will deepen your understanding of practical applications.
In groups, assign each member a role representing a component of the HVAC system (e.g., boiler, pump, fan coil unit). Conduct a role-play session where each “component” explains its function and interaction with other parts. This activity will enhance your comprehension of how each part contributes to the system’s overall efficiency.
Calculate the efficiency of a hypothetical HVAC system by considering factors such as boiler output, pump capacity, and heat loss in secondary circuits. Use real-world data and formulas to determine the system’s overall efficiency. This exercise will improve your analytical skills and understanding of system performance metrics.
Organize a visit to a commercial building with a modern HVAC system. Observe the system in operation, focusing on the interaction between boilers, circuits, and distribution units. Take notes on the system’s layout and any innovative features. This hands-on experience will provide practical insights into system design and functionality.
Sure! Here’s a sanitized version of the transcript:
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[Applause] Hey there, everyone! Paul here from theengineeringmindset.com. In this video, we are going to look at a typical modern heating system in a commercial building. There are many variations of how this can be configured, and I will make some videos to show you a few of these variations. However, this version is fairly typical of newer construction commercial buildings.
As you can see, we have two large boilers over here, and they are piped in parallel. This means that both boilers can operate at the same time or individually. One can be isolated for maintenance while the other continues to provide heating to the building. This is the most common type of configuration for modern heating systems. The other version would be series, but for this type of building, that’s not really practical.
Let me show you an example of what some of these large commercial boilers might look like. Here’s one I’ve worked on previously, and it’s fairly typical of the one shown in the 3D model. We have a large gas burner at the front and the main boiler unit over here. This is an older boiler, so you’re unlikely to come across these in newer builds. Newer heating systems may have smaller boilers that can change the demand of the building, and they may look something like this. Hoval is a well-known brand for boilers in commercial buildings, and these boilers are probably around 15 years old as well.
These boilers are the heat source for the heating system, and that heat is then pushed into the hot water of the heating system. One of the terms you’ll come across in these sorts of systems is “primary and secondary circuits.” Here, we have the primary pump set. These two pumps, which in the real world might look something like this, will push the water around the system. They will push the hot water that leaves the boiler into this pipework, where it is sucked by the pump and then pushed out into the low loss header, which we’ll look at shortly.
That water can then exit through these pumps into the risers, or some of it will continue through to the other side of the header. This is just one continuous pipe, and it will then return that water back to the boiler at a lower temperature to pick up more heat and continue the cycle.
Now, let’s look at an example of a low loss header. The boiler feed water comes into here, and this is the common header. The hot water enters here and can either leave through this pipe or continue down and back around into the boilers to pick up more heat. The water that leaves through these pipes can return through these ones, mixing with the flow from the boiler. This is known as the low loss header or common header.
Coming off of the header from the hot side are these risers, which make up the secondary circuits. In this example, we have four secondary circuits. Some have dual pumps, while others have a single pump. It may not need a pump if it’s close enough and the primary pumps are powerful enough, but in most cases, you will have a pump in this configuration.
Let me show you a secondary pump. These pumps will work to move the water up to where it’s needed. They usually work in duty and standby, meaning one pump is the working pump while the second is waiting for its turn. Usually, they won’t both run at the same time, but it is possible in some configurations. The pumps will cycle, so for one week, it might be pump one, and for the next week, it might be pump two as the duty pump. The standby pump will take over if the duty pump fails.
These secondary circuits take the water from the low loss header and push it up to where it’s needed. In the first loop, it feeds some radiators on the ground floor, and that water returns to the other side of the low loss header. The second secondary circuit rises up the height of the building, supplying hot water to all of the fan coil units.
The return water comes back into a riser and returns to the common low loss header. The third secondary circuit feeds into the air handling units (AHUs). The cooler water returns back to the low loss header to make its way back to the boiler for more heat.
Let me show you an example of the heating coil on an AHU. The water comes in from the secondary system, enters the heating coil, gives up its heat to the air, and then returns at a cooler temperature to the boiler.
The final secondary circuit feeds into a calorifier, where domestic hot water is produced. This is the hot water that comes out of the taps. There are chemicals in the primary heating system, and you don’t want to drink that. The hot water is fed into the calorifier and passes into a heat exchanger, transferring its heat into fresh water held inside the tank. This fresh water is then heated and supplied to kitchens and sinks.
Meanwhile, the cooler water returns back to the low loss header, mixes, and heads back to the boiler. Here’s an example of a calorifier configuration with the heat exchanger on the side.
You can also notice the expansion vessel and the pressurization unit. The pressure in the system will change based on various factors, such as pump operation and temperature changes. The expansion vessel and pressurization unit are connected to monitor and react to pressure changes, maintaining system balance.
The pipes in this diagram are color-coded. The red indicates high temperature, leaving the boiler at around 80 degrees Celsius (about 176 degrees Fahrenheit), while the yellow indicates lower temperature, returning at about 70 degrees Celsius (158 degrees Fahrenheit).
Here’s a schematic representation. We have the pressurization unit and expansion vessels, two boilers, and the water being pulled by the pump set into the low loss common header, forming the primary circuit. The secondary loops are also shown, with multiple valve configurations.
That’s it for this video! Thank you very much for watching. I hope this has helped you learn about these systems. If it has, please like and subscribe, and share the video with anyone who might find it helpful. Thanks for watching!
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Feel free to let me know if you need any further modifications!
Heating – The process of raising the temperature of a space or substance, often used in the context of thermal systems in engineering. – The heating system in the building was upgraded to improve energy efficiency and reduce operational costs.
Boilers – Devices used to generate steam or hot water by applying heat energy to water, commonly used in industrial and residential heating systems. – The engineers conducted a thorough inspection of the boilers to ensure they were operating safely and efficiently.
Circuits – Pathways or systems that allow the flow of electrical current, essential in the design and functioning of electronic devices and systems. – The electrical circuits in the laboratory were carefully designed to handle high voltage experiments.
Pumps – Mechanical devices used to move fluids, such as liquids or gases, by mechanical action, often used in various engineering applications. – The design team selected high-efficiency pumps to optimize the fluid transport system in the chemical plant.
Distribution – The process of delivering energy, fluids, or materials from a source to various destinations, crucial in engineering systems for effective resource management. – The distribution network was analyzed to identify potential bottlenecks and improve overall system performance.
Efficiency – The ratio of useful output to total input in a system, often used to measure the performance of machines and processes in engineering. – By implementing advanced control algorithms, the efficiency of the solar power system was significantly enhanced.
Temperature – A measure of the thermal energy within a system, critical in engineering for assessing system conditions and material properties. – The temperature sensors were calibrated to ensure accurate readings during the thermal testing phase.
Components – Individual parts or elements that make up a larger system, essential in engineering for building and maintaining complex machinery and structures. – The failure analysis revealed that one of the key components had a manufacturing defect, leading to the system malfunction.
Ventilation – The process of supplying fresh air and removing stale air from an environment, important in engineering for maintaining air quality and temperature control. – The ventilation system was redesigned to improve airflow and reduce energy consumption in the office building.
Monitoring – The continuous observation and recording of system parameters to ensure proper operation and detect any anomalies, vital in engineering for system maintenance and safety. – The monitoring system provided real-time data on the reactor’s performance, allowing engineers to make informed decisions.
