Ventilation System: Purpose, Types, Working Principle And Maintenance

Ventilation is very significant when it comes to controlling indoor air quality. In this article, I will be sharing with you almost everything you need to know about ventilation systems.


Ventilation is a combination of several processes that aid in the circulation and exchange of air within a building.


You can also define it as; ventilation is the process of supplying air and removal of air from space to improve the indoor quality.


So, this is a very important process as you will know in this article. Without wasting time, let me share with you what you need to know about this process.


Let me start sharing with you the purpose of this process and talk about how it works.


Purpose of ventilation;

Why do we need ventilation systems in our buildings? Is there any benefit of this system?


You will know about that in this section.


Here are two main functions of ventilation;

1. Ventilation is used to control the indoor temperature.

As we defined ventilation as a process of supplying and removal of air from space to improve the indoor quality, ventilation works to control the temperatures in a space.


The indoor air will contain higher temperatures compared to the air coming outside of the building.


This indoor air is usually heated by the activities done in that house.


Human beings emit heat, the electronic devices also emit heat when they are switched on, cooking and so many other activities done in the house result in the heating of the air.


When the air is heated, the indoor temperature will raise and this will bring discomfort to the people staying in that space.


So, it’s through ventilation that we get to control the temperature in the building.


The ventilation system will pull cooler air from outside the building to inside, since the indoor air is less dense as it hotter it will be displaced by the cooler air which is denser, thus controlling the indoor temperature.


We will be talking about the working principle of the ventilation system very soon.


2. Ventilation systems are used to control the moisture content within a building or firm.

This is another function of a ventilation system, apart from cooling the air it also controls the humidity within a building.


One of the requirements of a ventilation system is to maintain the humidity between 30% to 70%.


When the indoor air is dry or it has higher humidity than the accepted range, a ventilation system will pull the air out of the building and allow air with acceptable humidity to occupy the space.


As the ventilation controls the air temperature and moisture content in the building it will also be doing the following things;

  • It will be providing oxygen to the building and remove carbon dioxide out.
  • It will get rid of the odour.
  • It will also be diluting toxicity if there is any.


All these are functions of the ventilation systems.


Now that you know the need for the ventilation system let me share with you the type of ventilation systems and how they work.


Types of ventilation systems;

There are two main types of ventilation systems namely;

  • Natural ventilation.
  • Mechanical ventilation.


1. Natural ventilation.

A natural ventilation system is a ventilation system that mainly depends on the wind to work.


This type of ventilation system doesn’t need electricity for it to work, as long as there is wind the ventilation system will work.


Let me share with you how this works.

When the wind is blowing across a building, it will create a positive pressure to act on the windward side of the building, as a result of this, negative pressure will also be created on the leeward side.


The temperature difference between the outside and inside of the building will create a stack effect between the air inside and outside of the building.


The less-dense air that is inside the building will be displaced by the cooler air from outside the building.


This type of ventilation will largely depend on the wind and the vents that the building was built with.


The building should have an inlet on the windward side that is below lower and the outlet should be on the leeward side a little higher than the inlet vent.


This type of ventilation system is easily achievable but it’s not effective as the other method I will be sharing with you.


The main disadvantages of the natural ventilation system are that we can’t specify air change nor filter it before it enters the building also it’s unreliable since it depends on the wind.


If the air is dirty there is no way we can filter it before it enters the building.


The natural ventilation system doesn’t provide the option of filtering that air.


When there is no wind to create the stack effect then no ventilation will take place.


2. Mechanical ventilation system.

This is an effective system of ventilation since it’s improved compared to natural ventilation.


A mechanical ventilation system uses electrically driven fans to provide and extract air within the building.


But these mechanical ventilation systems are divided into several categories.


The mechanical ventilation systems are divided into three subcategories;

  • Natural inlet and mechanical extract.
  • Mechanical inlet and natural extract.
  • Mechanical inlet and extract.


The natural inlet and mechanical extract as it’s named depend on the natural wind to push the air within a building but the extraction of the indoor air is achieved by the electrically driven fan.


The fan creates negative pressure on its inlet as it rotates which causes the air to enter the building, while the air within the building is displaced by the cooler air from outside.


The mechanical inlet and natural extract depend on electric fans to suck the air inside the building but it will be extracted outside by a natural means e.g vents and windows.


Though there is an introduction of air being heated within the system. The air may be heated in a central system and then conveyed through ducts to various rooms.


It’s heated to increase its quality and make it easier for the fan to move the air into various ducts since it will be lighter.


Mechanical inlet and extract is the most efficient ventilation system but it’s quite expensive.


The air is normally filtered at the inlet and then heated before it’s conveyed to the rest of the building through the duct system.


After the air enters the building and then there will be a fan at the outlet that will extract the warm air out of the building.


This type of ventilation system is usually used in theatres, dance halls, restaurants, lecture theatres and cinemas.


The extract fan pressurizes the air in the building thus this requires the windows to be sealed and revolving doors to be used.


This internal air pressure within the building will prevent the entry of dust and noises.


Maintenance of ventilation system;

1. Checking for blocked filters.

This is one of the ways of maintaining ventilation systems.


You have to check for blocked filters and clean them so that you enable efficient circulation of air.


The moment the filters are blocked then the ventilation system will not work effectively.


As this will prevent maximum intake of air into the building.


2. Cleaning dirty heat exchange surfaces.

For ventilation systems that require heating, this is one of the factors that should be taken into consideration.


Cleaning dirty heat exchange surfaces will make the ventilation system efficient.


If the heat exchange surfaces are dirty then this will interfere with the heating system of the ventilation.


The air entering the building will not be heated effectively and this will affect the entire process of ventilation.


Cleaning the surfaces will give the chance for heat to be exchanged effectively.


3. Unblocking condensate drains.

The air entering the building will be cooler, which means it contains humidity, when it’s heated this will result to vapour droplets being formed that will be collected in the condensate drains.


If the condensate is blocked then the water will remain within the ventilation system and this will cause corrosion of some parts of the ventilation system.


Also, it will affect the humidity of the air.


Unblocking the condensate drains aids the water that is collected within the ventilation system to be drained.


4. Replacing damaged damper seals.

You have to replace the damaged damper seal if they are damaged to ensure that the improved air doesn’t leave the building.


If the damper seal is damaged then the air will escape from the ducts and the cooling will not be effective.


The ventilation system will use much energy for no important gain.


So, if your ventilation system is not working effectively you have to check out the damper seals, if they are damaged, change them.


5. Check exhaust fans.

The exhaust fans are important in the ventilation system as they aid in the circulation of air within the building.


Especially if it’s a mechanical inlet and extract, this will destroy the ventilation system.


The exhaust fans are used to extract the air within the building, if you will not check out on them and they end up having a fault then your ventilation system won’t work.


You will have to clean them and check if they are in good working condition.


When you do all this, you will be maintaining your ventilation system.


6. Cleaning of the ducts.

Cleaning of the duct is another important maintenance practice you should perform on your ventilation system.


One of the main functions of the ventilation system is to ensure that the air entering the building is clean.


If the ducts aren’t clean then you will not be able to have clean air within the building.


To get clean air you have to ensure the ducts are clean so that the air is conveyed in clean ducts.


This is all about ventilation system maintenance, if you have any questions about the ventilation system leave your comment.


See you in my next article.


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