Design FAQ

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Residential

What is HVAC mechanical design?
HVAC mechanical design is the process of designing a heating, ventilation, and air conditioning (HVAC) system to meet the needs of a particular space. This includes selecting the right components, such as air handlers, chillers, boilers, and pumps, and designing the ductwork and piping to ensure efficient and effective operation. The design must also consider factors such as energy efficiency, noise levels, and air quality. The goal of HVAC mechanical design is to create a system that meets the needs of the space while also being cost-effective and energy-efficient.
How to layout HVAC in house?

The layout of an HVAC system in a house depends on the size and shape of the house, as well as the type of system being installed. Generally, the system should be designed to provide adequate air circulation and temperature control throughout the house. To do this, the system should be designed to provide air flow to all rooms, with the air intake and exhaust vents located in the appropriate places. Additionally, the system should be designed to provide adequate insulation to prevent heat loss or gain. Finally, the system should be designed to provide adequate air filtration to ensure clean air is circulated throughout the house.

What is a residential HVAC system?

A residential HVAC system is a combination of heating, ventilation, and air conditioning systems designed to provide comfortable indoor temperatures and air quality in a home. The system typically consists of a furnace, air conditioner, and air handler, as well as ductwork and other components. The furnace is responsible for heating the air, while the air conditioner cools it. The air handler circulates the air throughout the home, and the ductwork distributes the air to each room. The system is designed to maintain a comfortable temperature and humidity level, as well as filter out airborne particles and pollutants.

What are the five main procedures in HVAC?

The five main procedures in HVAC are: 1) Heating – This involves the use of a furnace, boiler, or heat pump to provide warmth to a space. 2) Ventilation – This involves the use of fans, ducts, and other equipment to provide fresh air to a space. 3) Air Conditioning – This involves the use of an air conditioner to cool a space. 4) Humidification – This involves the use of a humidifier to add moisture to a space. 5) Filtration – This involves the use of filters to remove dust, pollen, and other airborne particles from a space. Each of these procedures is essential for providing a comfortable and healthy environment in any space.

Should HVAC be in ceiling or floor?

The best placement for HVAC systems depends on the type of system, the size of the space, and the desired air flow. Generally, ceiling-mounted systems are best for larger spaces, as they can provide more even air distribution. Floor-mounted systems are better for smaller spaces, as they can be more easily adjusted to provide targeted air flow. Ultimately, the best placement for HVAC systems should be determined by a professional HVAC technician, who can assess the space and determine the most efficient and effective placement for the system.

What are the criteria for HVAC design?

HVAC design criteria are the guidelines used to determine the size, type, and placement of HVAC equipment. The criteria should consider the building’s size, layout, occupancy, and climate. The design should also take into account the building’s energy efficiency goals, budget, and maintenance requirements. The criteria should also include the selection of the appropriate HVAC system components, such as air handlers, ductwork, and controls. Additionally, the design should consider the safety and comfort of the occupants, as well as the indoor air quality. Finally, the design should be compliant with all applicable codes and regulations.

What is difference between AC and HVAC?

AC (Air Conditioning) is a system that cools and dehumidifies the air in a space. It is typically used to cool a single room or area, and is usually powered by electricity. HVAC (Heating, Ventilation, and Air Conditioning) is a system that provides heating, cooling, and ventilation to a space. It is typically used to control the temperature, humidity, and air quality of an entire building or area, and is usually powered by electricity or natural gas. The main difference between AC and HVAC is that AC is used to cool a single room or area, while HVAC is used to control the temperature, humidity, and air quality of an entire building or area.

What are the four components of HVAC system?

HVAC systems are composed of four main components: heating, ventilation, air conditioning, and controls. Heating is the process of providing warmth to a space, typically through the use of a furnace, heat pump, or boiler. Ventilation is the process of exchanging air between the interior and exterior of a building, typically through the use of fans and ductwork. Air conditioning is the process of cooling and dehumidifying the air, typically through the use of an air conditioner. Finally, controls are the devices used to regulate the operation of the HVAC system, such as thermostats, dampers, and zoning systems. Together, these four components work together to provide a comfortable and safe indoor environment.

What is HVAC system architecture?

HVAC system architecture is the design of the components and systems that make up a heating, ventilation, and air conditioning system. It includes the layout of the ductwork, the size and type of equipment, the location of the thermostat, and the control systems used to regulate the system. The architecture of an HVAC system is designed to provide efficient and effective heating and cooling for a given space. It is important to consider the size of the space, the climate, and the desired comfort level when designing an HVAC system. The architecture should also be designed to ensure that the system is energy efficient and cost effective.

Others

What is the heating and cooling load of a HVAC system?

The heating and cooling load of a HVAC system is the amount of energy required to maintain a comfortable indoor environment. It is determined by the size of the space, the number of occupants, the type of equipment used, and the climate. The heating load is the amount of energy required to heat the space, while the cooling load is the amount of energy required to cool the space. The total heating and cooling load of a HVAC system is the sum of the two. To calculate the heating and cooling load, a professional HVAC technician will use specialized software to analyze the space and its occupants. This analysis will take into account factors such as insulation, air infiltration, and solar gain. The technician will then use this information to determine the size and type of HVAC system needed to meet the heating and cooling load requirements.

How do you calculate load for HVAC design?

The calculation of load for HVAC design is an important step in the design process. The load calculation is used to determine the size of the HVAC system needed to meet the heating and cooling needs of the space. The load calculation is based on the size of the space, the number of occupants, the type of construction, the orientation of the building, and the climate. The load calculation is typically done using a software program that takes into account all of these factors. The software will then calculate the heating and cooling load for the space and recommend the size of the HVAC system needed to meet the load.

What is heating load and cooling load?

Heating load and cooling load are two terms used to describe the amount of energy required to heat or cool a space. Heating load is the amount of energy required to raise the temperature of a space to a desired level, while cooling load is the amount of energy required to lower the temperature of a space to a desired level. Both heating and cooling loads are determined by factors such as the size of the space, the insulation of the space, the number of occupants, the climate, and the type of HVAC system used. The heating and cooling loads must be accurately calculated in order to properly size and install an HVAC system.

What is design cooling load?

Design cooling load is the amount of cooling energy required to maintain a comfortable indoor environment in a given space. It is determined by the size of the space, the amount of insulation, the number of windows, the type of construction, and the climate. The cooling load is typically expressed in British Thermal Units (BTUs) per hour. It is important to accurately calculate the design cooling load in order to select the right size of HVAC system for the space. An undersized system will not be able to adequately cool the space, while an oversized system will be inefficient and costly to operate.

What is load calculation in HVAC?

Load calculation in HVAC is the process of determining the amount of heating or cooling needed for a given space. It takes into account factors such as the size of the space, the number of windows, the insulation levels, and the climate. The load calculation is used to determine the size of the HVAC system needed to adequately heat or cool the space. It is an important step in the design process of any HVAC system, as it ensures that the system is properly sized to meet the needs of the space.

What is heat capacity in HVAC?

Heat capacity in HVAC is the amount of heat energy required to raise the temperature of a given mass of air by one degree. It is measured in British Thermal Units (BTUs) and is an important factor in determining the size of an HVAC system. Heat capacity is affected by the air’s humidity, pressure, and temperature, as well as the type of material used in the system. The higher the heat capacity, the more energy is required to raise the temperature of the air. Heat capacity is also used to calculate the efficiency of an HVAC system, as it helps to determine how much energy is needed to maintain a desired temperature.

What is the rule of thumb in HVAC design?

The rule of thumb in HVAC design is to size the system to meet the peak cooling and heating loads of the space. This means that the system should be able to provide enough cooling and heating capacity to meet the highest temperature and humidity levels that the space will experience. Additionally, the system should be designed to provide adequate air circulation and ventilation to ensure that the space is comfortable and healthy. Properly sizing the system is essential to ensure that the system is efficient and cost-effective.

How to calculate the design load?

The design load of an HVAC system is the amount of heating or cooling required to maintain a comfortable temperature in a given space. To calculate the design load, you need to consider the size of the space, the insulation of the building, the number of windows, the climate, and the number of occupants. You can use a variety of tools, such as a heat loss calculator or a Manual J load calculation, to determine the design load. These tools will help you determine the amount of heating or cooling required to maintain a comfortable temperature in the space. Additionally, you can use a Manual S calculation to determine the size of the HVAC system needed to meet the design load.

How do you calculate design load capacity?

Design load capacity is calculated by taking into account the total heat gain from all sources, such as people, lights, and equipment, and subtracting the total heat loss from the building envelope. This calculation is based on the building’s size, orientation, insulation, and other factors. The total heat gain is then divided by the total cooling capacity of the HVAC system to determine the design load capacity. This calculation should be done by a qualified HVAC technician to ensure accuracy and efficiency.

What is the design temperature for cooling load?

The design temperature for cooling load is the temperature at which the cooling system must be able to operate in order to meet the cooling needs of the building. This temperature is determined by the climate of the area, the type of building, and the desired indoor temperature. Generally, the design temperature for cooling load is set at the highest temperature that the building is expected to experience during the hottest months of the year. This temperature is usually between 75-95°F, depending on the climate and the building’s insulation.

What is BTU in heat load calculation?

BTU, or British Thermal Unit, is a unit of measurement used in heat load calculations. It is used to measure the amount of energy required to raise the temperature of one pound of water by one degree Fahrenheit. Heat load calculations are used to determine the size of the HVAC system needed to adequately heat or cool a space. The calculation takes into account the size of the space, the number of windows, the insulation of the walls, and other factors. The BTU measurement is then used to determine the size of the HVAC system needed to provide the desired temperature.

What are the different types of heating and cooling loads?

Heating and cooling loads can be divided into two main categories: sensible and latent. Sensible loads refer to the energy required to raise or lower the temperature of the air, while latent loads refer to the energy required to add or remove moisture from the air.

Within the sensible load category, there are two types of loads: sensible heat gain and sensible heat loss. Sensible heat gain is the energy required to raise the temperature of the air, while sensible heat loss is the energy required to lower the temperature of the air. Within the latent load category, there are two types of loads: latent heat gain and latent heat loss. Latent heat gain is the energy required to add moisture to the air, while latent heat loss is the energy required to remove moisture from the air.

What is design condition in HVAC?

Design condition in HVAC is the set of conditions that the system is designed to operate under. This includes the temperature, humidity, and air pressure of the space, as well as the type of equipment used. Design conditions are used to ensure that the system is able to meet the desired comfort levels and energy efficiency goals. Design conditions are also used to determine the size and capacity of the system, as well as the type of components and materials used.

How do you calculate cooler design?

Cooler design is calculated by determining the required cooling capacity of the system. This is done by calculating the total heat load of the space, which is the sum of the sensible and latent heat loads. The sensible heat load is determined by the size of the space, the number of occupants, and the amount of equipment in the space. The latent heat load is determined by the amount of moisture in the air. Once the total heat load is calculated, the required cooling capacity can be determined by multiplying the total heat load by the desired temperature difference. The required cooling capacity is then used to determine the size of the cooler needed for the space.

What is design day in HVAC?

Design day in HVAC is a term used to describe the worst-case scenario for a building’s heating and cooling needs. It is based on the hottest and coldest days of the year, and is used to determine the size and capacity of the HVAC system needed to meet the building’s needs. Design day is also used to determine the efficiency of the system, as well as the amount of energy needed to operate it. Design day is an important factor in the design of any HVAC system, as it ensures the system is able to meet the building’s needs in the most extreme conditions.

What is commercial in HVAC?

Commercial HVAC systems are designed to provide heating, cooling, and ventilation for large commercial buildings such as office buildings, retail stores, and warehouses. These systems are typically larger and more complex than residential HVAC systems, and require specialized knowledge and expertise to install and maintain. Commercial HVAC systems are designed to provide a comfortable environment for occupants, while also being energy efficient and cost effective. They typically include multiple components such as air handlers, chillers, boilers, and air conditioning units, as well as ductwork and controls. Commercial HVAC systems are designed to meet the specific needs of the building, and must be regularly maintained to ensure optimal performance.

How do you size an HVAC system for a commercial?

Sizing an HVAC system for a commercial space requires a thorough understanding of the building’s size, layout, and usage. The first step is to calculate the building’s cooling load, which is determined by factors such as the number of occupants, the amount of insulation, the type of windows, and the climate. Once the cooling load is calculated, the next step is to select the appropriate HVAC system size. This is done by comparing the cooling load to the system’s capacity, which is measured in tons. The system should be sized to meet the cooling load, but not exceed it. Finally, the system should be installed and tested to ensure it is operating correctly and efficiently.

What’s the difference between commercial and industrial HVAC?

Commercial HVAC systems are designed to provide heating, cooling, and ventilation for buildings such as offices, stores, and restaurants. These systems are typically smaller in size and are designed to meet the needs of a smaller space. Industrial HVAC systems are designed to provide heating, cooling, and ventilation for larger, more complex spaces such as factories, warehouses, and other industrial facilities. These systems are typically larger and more powerful, and are designed to meet the needs of a larger space. Additionally, industrial HVAC systems often require more specialized components and maintenance due to the complexity of the space and the equipment.

What does HVAC design include?

HVAC design includes the selection and sizing of all components of the system, including the air handler, ductwork, and other components. It also includes the selection of the appropriate type of system, such as a split system, packaged system, or rooftop unit. Additionally, HVAC design includes the selection of the appropriate type of refrigerant, the selection of the appropriate type of air filter, and the selection of the appropriate type of insulation. Finally, HVAC design includes the selection of the appropriate type of controls, such as thermostats, zoning systems, and humidistats. All of these components must be carefully selected and sized to ensure the system is efficient, reliable, and cost-effective.

Which HVAC system is used in commercial building?

The most common HVAC system used in commercial buildings is a split system. This type of system consists of two components: an outdoor unit and an indoor unit. The outdoor unit contains the compressor, condenser, and expansion valve, while the indoor unit contains the evaporator coil, blower, and air filter. The two units are connected by refrigerant lines, which allow the system to transfer heat from the indoor environment to the outdoor environment. Split systems are popular in commercial buildings because they are energy efficient, reliable, and easy to maintain. Additionally, they can be customized to meet the specific needs of the building.

How is commercial HVAC different from residential?

Commercial HVAC systems are designed to meet the needs of larger, more complex buildings than residential systems. Commercial systems are typically larger in size and more powerful, allowing them to provide more efficient heating and cooling for larger spaces. Additionally, commercial systems often include more advanced features such as zoning, humidity control, and air filtration. These features are not typically found in residential systems. Commercial systems also require more frequent maintenance and servicing due to their larger size and complexity. This is to ensure that the system is running efficiently and safely.

What are the two types of HVAC system design?

The two main types of HVAC system design are centralized and decentralized. Centralized systems are typically used in larger buildings and involve a single, centralized unit that distributes air throughout the building. Decentralized systems are typically used in smaller buildings and involve multiple, smaller units that are located throughout the building. Both types of systems are designed to provide efficient and effective heating, ventilation, and air conditioning.

What are the four main types of HVAC systems?

The four main types of HVAC systems are split systems, packaged systems, hybrid systems, and ductless mini-split systems. Split systems are the most common type of HVAC system and consist of an outdoor unit and an indoor unit. The outdoor unit contains the compressor, condenser, and expansion valve, while the indoor unit contains the evaporator coil and air handler. Packaged systems are all-in-one units that contain the compressor, condenser, evaporator coil, and air handler in one unit. Hybrid systems are a combination of split and packaged systems, with the outdoor unit containing the compressor, condenser, and expansion valve, and the indoor unit containing the evaporator coil and air handler. Lastly, ductless mini-split systems are similar to split systems, but they do not require ductwork and are more energy efficient.

How to design a HVAC system for a building?

Designing a HVAC system for a building requires careful consideration of the building’s size, layout, and climate. The first step is to calculate the building’s heating and cooling loads, which will determine the size of the system needed. This can be done using a variety of methods, such as Manual J or a computer simulation. Once the size of the system is determined, the next step is to select the type of system that best meets the building’s needs. This includes selecting the type of equipment, such as a furnace, air conditioner, or heat pump, as well as the type of ductwork and ventilation system. Finally, the system must be installed and tested to ensure it is operating correctly and efficiently.

How do you calculate HVAC load in commercial buildings?

Calculating HVAC load in commercial buildings requires a few steps. First, you need to determine the total square footage of the building. This can be done by measuring the length and width of each room and multiplying them together. Next, you need to calculate the heat gain and heat loss of the building. This can be done by taking into account the insulation, windows, and other factors that affect the building’s energy efficiency. Finally, you need to calculate the total HVAC load by multiplying the total square footage by the heat gain and heat loss. This will give you the total HVAC load for the building.

What is the largest Commercial HVAC manufacturer?

The largest commercial HVAC manufacturer is Carrier Corporation. Carrier is a subsidiary of United Technologies Corporation and is one of the world’s leading providers of heating, ventilation, air conditioning, and refrigeration systems. Carrier offers a wide range of products and services, including commercial and residential HVAC systems, air filtration systems, and energy-efficient solutions. Carrier is also a leader in the development of innovative technologies, such as variable refrigerant flow systems and advanced air filtration systems. Carrier’s products are designed to meet the highest standards of quality and performance, and are backed by a global network of service and support.

What is the best HVAC system for a high-rise building?

The best HVAC system for a high-rise building depends on the size and layout of the building, as well as the climate and local weather conditions. Generally, a rooftop unit is the most efficient and cost-effective option for a high-rise building. This type of system is designed to provide efficient cooling and heating for large buildings, and can be easily installed on the roof of the building. Additionally, rooftop units are designed to be energy-efficient, helping to reduce energy costs. For buildings with multiple floors, a split system is often the best option. This type of system uses two separate units, one located inside the building and one located outside. The indoor unit is responsible for distributing air throughout the building, while the outdoor unit is responsible for cooling and heating the air. Split systems are highly efficient and can be customized to meet the specific needs of the building.

What are the parts of a commercial HVAC system?

A commercial HVAC system typically consists of four main components: an air handler, a condenser, a compressor, and a thermostat. The air handler is responsible for circulating air throughout the building, while the condenser is responsible for cooling the air. The compressor is responsible for pressurizing the refrigerant, and the thermostat is responsible for controlling the temperature. Additionally, commercial HVAC systems may also include ductwork, dampers, and other components to ensure proper air flow and temperature control.

How does HVAC work in high-rise?

HVAC systems in high-rise buildings are designed to provide efficient and effective climate control for the occupants. The system typically consists of a central air handling unit, which is connected to a network of ducts and vents that distribute conditioned air throughout the building. The air handling unit is responsible for heating, cooling, and filtering the air, and is usually connected to an outdoor unit that provides fresh air to the building. The system is also connected to a thermostat, which allows the occupants to adjust the temperature to their desired level. The system is designed to maintain a comfortable temperature throughout the building, while also providing adequate ventilation to prevent the buildup of pollutants.

Why is high rise HVAC a challenge?

High rise HVAC systems present a unique challenge due to the complexity of the building structure and the need to provide adequate air flow and temperature control throughout the building. The height of the building means that the air pressure is lower at the top, making it difficult to move air through the system. Additionally, the building’s structure can cause air to become trapped in certain areas, leading to uneven temperatures and air flow. Finally, the sheer size of the building can make it difficult to install and maintain the system, as well as to ensure that all areas of the building are adequately heated and cooled.

Which type of air conditioning system is suitable for large buildings and gyms?

For large buildings and gyms, a central air conditioning system is the most suitable option. This type of system is designed to cool multiple rooms or areas at once, and can be used to regulate the temperature of large spaces. It works by circulating cooled air through a network of ducts, which are connected to a central air handler. This air handler is typically located in a basement or attic, and is connected to an outdoor condenser unit. Central air conditioning systems are highly efficient and cost-effective, making them an ideal choice for large buildings and gyms.

How to design a HVAC system for a high-rise building?

Designing a HVAC system for a high-rise building requires careful consideration of the building’s size, layout, and climate. The system should be designed to provide adequate air circulation, temperature control, and humidity control. To ensure efficient operation, the system should be designed to take into account the building’s orientation, the number of occupants, and the type of activities that will take place in the building. Additionally, the system should be designed to accommodate the building’s ventilation requirements, such as natural ventilation, mechanical ventilation, and air conditioning. Finally, the system should be designed to meet the building’s energy efficiency requirements, such as using energy-efficient equipment and insulation.

How do you ventilate a high rise building?

Ventilating a high rise building requires a comprehensive system that takes into account the building’s size, layout, and climate. The most common approach is to install a mechanical ventilation system, which uses fans to draw in fresh air from outside and exhaust stale air from inside. This system can be supplemented with natural ventilation, such as windows and vents, to provide additional air flow. Additionally, air filters should be installed to ensure that the air quality is maintained. Finally, the system should be regularly inspected and maintained to ensure that it is operating efficiently and safely.

How do you air condition a skyscraper?

Air conditioning a skyscraper requires a complex system of ducts, vents, and other components. The most common method is to use a central air conditioning system, which consists of an outdoor condenser unit, an indoor evaporator coil, and a series of ducts to distribute the cooled air throughout the building. The condenser unit pumps refrigerant through the evaporator coil, which absorbs heat from the air and cools it. The cooled air is then distributed through the ducts to the various rooms in the building. Additionally, the system may include a thermostat to control the temperature and a humidifier to maintain the desired humidity level. Proper installation and maintenance of the system is essential to ensure the building is properly cooled.

How do you calculate HVAC design for high-rise building?

Calculating HVAC design for a high-rise building requires a comprehensive understanding of the building’s layout, size, and occupancy. The first step is to determine the building’s cooling load, which is the amount of energy required to cool the building. This can be calculated by taking into account factors such as the building’s insulation, window size, and orientation. Once the cooling load is determined, the next step is to select the appropriate HVAC system for the building. This includes selecting the right type of equipment, such as air conditioners, chillers, and boilers, as well as the right size and capacity. Finally, the system must be properly installed and maintained to ensure optimal performance.

What is an AHU in hospitals?

An AHU (Air Handling Unit) is a critical component of a hospital’s HVAC system. It is responsible for providing a comfortable and safe environment for patients and staff. AHUs are typically located in the mechanical room and are responsible for controlling the temperature, humidity, and air quality of the hospital. They are designed to filter, condition, and distribute air throughout the building. AHUs are also responsible for controlling the air pressure within the hospital, which helps to prevent the spread of airborne diseases.

Do hospitals have air conditioning?

Yes, hospitals do have air conditioning. HVAC systems are essential for providing a safe and comfortable environment for patients, staff, and visitors. Air conditioning helps to maintain a consistent temperature and humidity level, which is important for preventing the spread of airborne diseases. Additionally, air conditioning helps to reduce the risk of heat-related illnesses, which can be especially dangerous for vulnerable patients.

What is HVAC in pharmaceutical industry?

HVAC in the pharmaceutical industry is a critical component of the manufacturing process. It is responsible for controlling the temperature, humidity, and air quality of the environment in which pharmaceutical products are produced. HVAC systems are designed to maintain a consistent temperature and humidity level, as well as to filter out airborne contaminants, such as dust and bacteria. This helps to ensure that the products produced are of the highest quality and meet all regulatory requirements. Additionally, HVAC systems are used to maintain a comfortable working environment for employees, as well as to reduce energy costs.

Why is AHU used in pharmaceutical industry?

AHU (Air Handling Unit) is an important component of HVAC systems used in the pharmaceutical industry. AHU is used to control the temperature, humidity, and air quality of the environment. It helps to maintain a clean and sterile environment, which is essential for the production of pharmaceutical products. AHU also helps to reduce the risk of contamination by filtering out dust, pollen, and other airborne particles. Additionally, AHU helps to reduce energy costs by controlling the temperature and humidity levels, which can help to reduce the overall operational costs of the pharmaceutical industry.

Why is HVAC necessary for pharmaceuticals?

HVAC systems are essential for pharmaceuticals because they provide a controlled environment for the production and storage of drugs. HVAC systems help maintain a consistent temperature and humidity level, which is critical for the stability of pharmaceuticals. They also help reduce the risk of contamination by filtering out airborne particles and controlling the air pressure. Additionally, HVAC systems help reduce energy costs by providing efficient cooling and heating. By controlling the environment, HVAC systems help ensure that pharmaceuticals are produced and stored safely and effectively.

Why air is used in hospital?

Air is used in hospitals for a variety of reasons. Firstly, it is important to maintain a clean and sterile environment in order to prevent the spread of infection. Air is used to circulate fresh air throughout the hospital, removing any airborne contaminants and providing a healthy environment for patients and staff. Additionally, air is used to regulate the temperature of the hospital, ensuring that it is comfortable for everyone. Finally, air is used to control humidity levels, which is important for patient comfort and to prevent the growth of mold and bacteria.

Do hospitals pump oxygen into the air?

No, hospitals do not pump oxygen into the air. Hospitals use HVAC systems to maintain a comfortable temperature and humidity level, as well as to filter out airborne contaminants. The air is circulated through a series of filters to remove dust, pollen, and other particles. The air is then heated or cooled as needed, and humidified or dehumidified to maintain a comfortable environment. Oxygen is not added to the air, as it is already present in the atmosphere.