HVAC Systems

HVAC Systems

HVAC systems

The HVAC system is one of the most important components of any building because it ensures the residents’ comfort. HVAC combines heating, ventilation, and air conditioning systems designed to regulate temperature and humidity levels inside a building. This system stands for the initial letters of ‘Heating, Ventilating, and Air Conditioning.’ The HVAC system also helps maintain air quality and reduce emissions by filtering pollutants in the air. A suitable HVAC system can be beneficial in reducing the energy caused by heating and cooling. If the HVAC system is not designed correctly, it may cost a lot to keep the building warm or to cool the air inside the building, but in the end, the desired temperature for the comfort of the residents will not be achieved in all parts of the building.

Designing an operating system is a determining factor in building design. Designers and architects know that HVAC systems can reduce energy consumption, save costs, and provide occupant comfort. Therefore, one of the main parts of the architecture of any building is predicting the right place for HVAC systems.


HVAC in various systems, including vehicles such as cars, ships, trains, and airplanes, and in general, the places where people are present, must be designed based on environmental regulations to provide proper ventilation and air quality for people. Failure to design a suitable HVAC system can lead to people’s dissatisfaction and problems such as heatstroke or frostbite or breathing problems.

Although the three main functions of HVAC are separate from each other, all three are related and work together to achieve proper heating and air quality.

A proper HVAC system provides adequate ventilation and air passage conditions and adjusts the air pressure between different building parts. In this system, air transfer means uniform air distribution with the same temperature (without temperature gradient) in that environment.


HVAC investigates optimal breathing conditions and also provides them. In general, the main goals of air conditioning systems are establishing cooling and heating and increasing humidity in dry air or drying environments with high humidity. Humans are considered to have suitable moisture between 30 and 50% and a suitable temperature for the atmosphere between 22-25 degrees Celsius.

HVAC is one of the most important mechanical systems in any building. Ventilation systems can be classified according to the different climate zones or the performance we are considering. Primary HVAC equipment includes heating, ventilation, and cooling or air conditioning equipment.

CFD analysis in HVAC systems

Computational fluid dynamics (CFD) is an essential tool for designing, analyzing, and optimizing the performance of HVAC systems. CFD can be used to simulate airflow inside a building and predict the effect of ambient air temperature. That helps engineers design better systems that provide more efficient heating and cooling while reducing energy costs for cooling or heating.

CFD can also be used to analyze existing systems that have already been designed and identify system strengths that can reduce energy consumption or improve air quality. Using CFD, engineers can develop more efficient HVAC systems that meet their customers’ needs while reducing operating costs. CFD is used in many HVAC systems, some of which are discussed below.


Undoubtedly, the spread of the Coronavirus is one of the biggest problems that have plagued the community in recent years, which has infected many people worldwide. Today, the world community is still fighting against this virus. Since the spread of this virus, many strategies have been adopted to prevent its further spread, and wearing a mask on the face is one of these strategies. But despite wearing a mask, there is a possibility of spreading this virus.

Therefore, suitable air conditioning systems should be provided for public places, especially hospitals, to prevent the spread of this virus as much as possible. Using the discrete phase method in Fluent software, it is possible to simulate the movement of solid particles (here, the coronavirus) and track their movement path. So we can track the spread of the virus by simulating different ventilation systems in the desired location. And design the best air conditioning system to control the virus and prevent it from spreading further.


Greenhouses are artificial spaces for growing plants and fruits. In the past, each fruit or plant grew in its season, but today, with the expansion of greenhouses and the provision of suitable air for plants and trees, we can increase the products of other seasons each season. Greenhouses are usually used in winter to keep the space warm and grow summer plants.


As mentioned, the main advantage of greenhouses is to keep the air around the plants warm. And heating is also one of the HVAC systems. In addition to heating, because plants consume oxygen and emit carbon dioxide, greenhouses must also have a suitable air conditioning system so that the plants do not suffer from suffocation and the oxygen get their needs. CFD comes to our aid here as well. We can simulate different air conditioning systems according to the greenhouse space and optimally design the required HVAC system before spending high costs to build an air conditioning system.

Ventilation of tunnels

Tunnels are places for the passage of light and heavy vehicles. Due to the polluting nature of many cars, the accumulation of pollutants in tunnels can be dangerous. According to reports of incidents that happened in the past, we faced the problem of motorcyclists fainting in long tunnels. In long tunnels, the lack of proper ventilation caused the concentration of pollutants such as carbon monoxide to increase. This caused the motorcyclists to become unconscious.

Due to this problem, engineers realized the importance of a proper ventilation system in tunnels. Therefore, today we see that large and noisy fans are installed in long tunnels to move polluted air from inside the tunnel to outside. Now, the main question is how many fans do we need and with what specifications, such as the diameter of the impeller, the airflow rate, the distance between the fans, etc.?

Here we can use CFD to find the answer to our question. Using CFD and simulating different modes for the type and size of fans, we can design the appropriate air conditioning system.



A server room is where all servers, switches, routers, and other equipment of large organizations are kept. Every company or large organization considers a separate room to protect its equipment; this room is essential for the organization. It is high because all the vital information of the past years is kept there. Therefore, the protection of this room is also of great importance. In this room, all the functioning of the equipment and servers are checked continuously and daily because, in case of a small problem, all the stored information of the organizations may be lost. Or if there is a malfunction in this system’s performance, the entire organization’s performance may be disrupted. For example, influential organizations such as broadcasting or telecommunications are organizations where the server room is important.

server room

This room must be kept clean and free of any kind of dust. On the other hand, electronic equipment generates heat and increases the temperature continuously. Therefore, a suitable ventilation system is necessary for dust removal and cleanliness, as well as the cooling of the equipment. CFD can help solve this problem and design a suitable air conditioning system. To simulate these rooms, we can define the heat production of the servers with a thermal sources term on the border of the servers. And to track the dust, use the discrete phase model. By simulating these systems, we can optimize air conditioning systems for better cooling and proper ventilation to prevent harmful incidents in this sensitive room.

server room ,CFD

Metro HVAC

Another place where the air conditioning system is essential is metro stations. The metro is an intra-city rail transportation system. The metro is generally built in crowded cities. Most of the metro rail network extends underground, and the metro stations are also underground. Every day, thousands of people commute to metro stations. Therefore, these stations must have suitable conditions for people’s breathing in terms of air conditioning. On the other hand, with the spread of the coronavirus, since metro stations can be very crowded, the risk of contracting the virus also increases for people. Therefore, the ventilation system of the metro should be designed in such a way as to prevent the spread of the virus.

In addition to metro stations, metro wagons are places where people gather. There are more people in wagons than in stations. Therefore, the importance of a metro HVAC system for cooling or heating and air conditioning for wagons is felt much more than before. CFD can help engineers design these HVAC systems and reduce the challenges ahead in developing these systems.