What is forced ventilation, is it necessary in the house and is it worth spending money on another system if you did without it before?? These questions are asked today by many home owners and specialists who are involved in the design and construction of private houses and apartments. Let’s try to answer them in detail.
Ventilation in the house: yesterday and today
Normal is considered to be the air exchange, at which the air in the dwellings is renewed every hour. This helps to maintain the necessary concentration of oxygen for normal breathing, which in the exhaust air is replaced by carbon dioxide, as well as promptly get rid of a variety of malodorous impurities, bacteria and microbes, without allowing their concentration to become dangerous. In the past, this was solved with passive ventilation systems. But today it is not always possible.
The fact is that some 30 years ago individual housing in our country was more an exotic than an industry, except for summer cottages. In addition, the building materials and design solutions used at the time, such as leaking wooden windows, combined with passive extraction ventilation provide a relatively small area private houses and apartments fairly efficient natural air exchange. Therefore, forced-air intake and exhaust ventilation systems were not used in the private sector, and planners had no experience in their use.
Today the situation is completely different. Capital detached houses have become a prestigious norm, including in the boundaries of cities with a population of millions. Their area and accordingly the internal volume has increased significantly, and energy-saving windows and metal doors with a quality seal when closed leave no room for a natural air exchange. That is why almost every such house needs a forced ventilation system.
The desire of owners to save energy resources is also becoming a significant factor. Today the heating of even a modest individual cottage costs a pretty penny for the owners and is the most significant item of utility costs. At the same time, passive ventilation is the source of the largest heat losses, which in a properly insulated house are comparable with the heat losses through the walls. Therefore, every year more and more widespread forced ventilation systems are.
The situation in urban apartment buildings is also quite ambiguous. Now all apartments in new buildings are equipped with air inlet valves, which are usually built into the outer walls next to the windows. Valves should provide the necessary inflow of fresh air from the street. However, this system works effectively only in conjunction with passive exhaust ventilation, which is far from always meets expectations. In addition, in old buildings there are no valves, and the owners usually change wooden windows for plastic ones.
Finally, the standard efficiency of air exchange itself is not satisfactory for everyone. In addition, it can suffer as a result of various alterations and overcrowding in housing, which is also not uncommon.
How much air do you need to breathe?
Nor should we forget that the respiratory oxygen demand is continually growing. As scientific research shows, the concentration of carbon dioxide in the Earth’s atmosphere is constantly increasing and has now reached dangerous levels. At the same time the oxygen content is going down, and although this change is very gradual and not dangerous yet, scientists are alarmed by the speed of the process: in the last 100 years the oxygen concentration has dropped by the same amount as it used to drop in about 115 thousand years.
The effect of urbanization also has to be taken into account. If on average the concentration of oxygen in the atmosphere varies around 21%, in the city air is usually not more than 20.8%, and inside buildings the concentration sometimes decreases to a dangerous level – 20.3% noticeable physiological effects of oxygen starvation in humans begins at 20.6% . And in such conditions people spend up to 80 % of their time.
Therefore, the issue of organization of forced supply and exhaust ventilation, capable of fully refresh the air in habitable rooms every hour for the owners of urban apartments are sometimes no less urgent than for homeowners. But if the latter have the necessary space and opportunities for any redevelopment, the citizens are limited in them both physically and legislatively.
In practice, the device forced ventilation in a private house or in an urban apartment – one of the most serious problems facing their owners and their invited professionals. Experience shows that designing ventilation sometimes raises more questions than designing heating and electrical systems, which from a technical point of view seem to be more complicated. Fortunately, today there are other solutions that allow you to quickly select and install a system for both individual houses and city apartments.
Turnkey solution for any size of home
In 2018, Viessmann, a leader in innovation in heating and life support systems, introduced in America a ventilation system concept for apartments and private homes based on the Vitovent 300 universal ventilation unit with heat recovery, designed for wall mounting and powered by a 220 V 50 Hz household power grid, which is connected via an ordinary plug socket.
Depending on the modification, the central unit provides a regulated air exchange of up to 300 or 400 m3 /h. To recuperate heat, the exhaust air is passed through a countercurrent heat exchanger where it gives off heat to the fresh outside air. This allows you to significantly reduce heat loss and save on heating bills or the purchase of fuel.
All the units are equipped with a filter system to eliminate dust, impurities and unpleasant odours from the incoming air. Both models, beside the heat exchanger, have a built-in heat exchanger optional
electrically operated thermostatic bypass valve. This element automatically switches the recovery mode on and off depending on the outside air temperature so that in summer time it is not heated by the outgoing air. This reduces the load on the air conditioning system.
The system is controlled via a programmable digital controller that has many built-in modes and allows the user to set their own. If necessary, it can be supplemented with humidity and temperature sensors to automatically maintain the appropriate level. The central unit itself can be installed in e.g. a storage room, utility room, kitchen, insulated loggia or attic in the case of private homes .
With more than modest power consumption 138 watts for the low and 192 watts for the high version the unit provides heat recovery with efficiency up to 93. The head created by the fans reaches 175 Pa at maximum performance, which allows for the use of sufficiently long ducts. Thanks to these and other advantages, the solution has been certified by the Passive House Institute.
If the installation of a duct system is not possible in an apartment e.g. due to lack of space , the Vitovent 100-D or Vitovent 050-D decentralised ventilation solutions are more compact. The units with ceramic recuperators are built directly into the outer wall of the room and provide air exchange of 43-45 m3/hour with heat and humidity recuperation. The control unit regulates the air exchange rate, reverses the airflow direction and monitors the relative humidity level.
Oxygen enrichment
In some cases, particularly in environmentally hostile cities, forced ventilation alone may not be sufficient. The air quality can be further improved with special solutions for artificial oxygen enrichment.
They are based on membrane filtration technology commonly used in chemical, microbiological and food industries. In this case, a polymer membrane is used, which has a different permeability for oxygen and nitrogen molecules: The former pass through it quite easily, while the latter are retained by the polymer film. If this membrane is placed in the airflow path, the air blown through it is substantially enriched with oxygen.
One application that the technology has found in the Atmung OxyHaus oxygen concentrator. the device extracts from the street air and gives into the room near 100% oxygen in small amounts that are, however, quite enough to increase its concentration in the inhaled air. Company Panasonic has applied the same decision in due time and has equipped some models of split-systems with oxygen concentrators O2 Shower.
When using them in conjunction with supply and exhaust ventilation, it is important to place them correctly so that the tube or valve, through which oxygen enters the room, is located near the supply grille or is built directly into the duct that carries fresh air into the room.
An alarming increase in the concentration of carbon dioxide in the atmosphere and other adverse factors have a bad effect on human health. And we often find ourselves in such a situation through our own fault, insulating our houses and plugging all the cracks, but we do not care about the organization of a normal air exchange. But thanks to the universal system of apartment ventilation and other technical means, this problem can now be solved by anyone.
“How can we ensure that every home has access to fresh air, especially in heavily polluted areas, and what are the possible solutions to improve air quality indoors for better health?”
How can we ensure that every household, especially in densely populated areas, has access to fresh air?
This is a great initiative! I’m curious, how is “fresh air to every home” being achieved? Are there specific methods or technologies being utilized to ensure the air is clean and healthy?
How can we ensure that every home has access to fresh air?