Select your language

Cleaning and disinfection in air conditioning systems

Limpieza y desinfección en sistemas de aire acondicionado

Keep in mind these recommendations to preserve and ensure Indoor Air Quality in this type of solutions.

by Carolina González*

Before we start talking about cleaning and disinfecting air conditioning systems, I would like to mention a maxim of quality management systems: "The cleanest place is not the one that gets the cleanest, it's the one that gets dirty the least." What does this appointment come to?

When we refer to air conditioning systems we are talking about all its components, from the equipment that conditions it to the devices that distribute it in the conditioned enclosure, packages, air handling units (UMAs), ducts, diffusers, etc. The expression applies very well because if the system is equipped with the elements that allow it to be kept clean, that is, they prevent the entry of dust (filters), odors or gases (chemical filtration), pathogens (UVC emitters), etc. it is most likely that the maintenance of the entire system is limited to checking that the aforementioned elements are in optimal conditions all the time.

- Publicidad -

Below, the various alternatives that exist to clean and keep hygienic (disinfected) air conditioning systems will be presented and analyzed. We will assume that, although the systems had from the beginning the necessary elements to stay clean according to their application, these at some point lost their effectiveness or, at this time, these components are not enough to guarantee the use of air conditioning systems in the current health emergency situation.

Identify contaminants
To have and keep an air conditioning system clean, the first thing we must do is determine the type of contaminants to which it will be or was exposed, that is, identify what we must eliminate from the system and know what we must do next to avoid or minimize the presence of those contaminants for future operation.

With this analysis we will be able to know the actions to disinfect our systems as well as the necessary equipment to install to avoid contamination.
It is not the same to clean and keep clean a system that has been exposed to the exhausted of kitchens, than one that has been processing air from the city or from a certain type of industry (oil, paper, pharmaceutical, etc.), or even more from an enclosure dedicated to health care.

Now, cleaning and / or disinfecting a system must have as a final result that it is ready to distribute safe air for the users of the conditioned areas, that is, it must be free of contaminants that put health at risk, and for this it is necessary to clean all the elements that constitute the system with the method, necessary tools and materials, therefore we must clean to remove dust, chemical materials and especially biological contaminants.

Cleaning methods, tools and materials
To remove dust we do what is called physical cleaning, that is, we use elements such as brushes, vacuum cleaners, etc. For example, in the case of UMAs and / or package type equipment, the first thing we must do is make sure that the equipment is and will remain off during the entire cleaning operation (a safety lock must be placed on the switch that supplies the power to the equipment). Subsequently, all the filters must be removed, the brush or broom or rag must be passed through the rails where the filters are installed, through the floor and walls of the equipment.

We must also use a vacuum cleaner to prevent dust from migrating or entering the duct or being impregnated in the coil. When the (physical) cleaning is done in the ducts, these tools are adapted to move within the network of ducts and for this you can use rotary brushes coupled to mobile elements (chicotes) that are operated manually or that are mounted on robots that will also be equipped with cameras that allow remote manipulation of the device to achieve better cleaning.

- Publicidad -

On some occasions, it is necessary to use a chemical compound to remove certain types of dirt that is impregnated, this can be called chemical cleaning. A good example can be the impregnation of salts in the coils or the grease in some ducts. Whenever chemical substances are used, we must take care of two aspects, the first is the safety of the operator who is going to apply it, that is, we must know the effects that this product can cause and therefore we must provide our staff with the appropriate PPE; the second aspect, no less important, is how this substance affects our system (equipment or duct), that is, we must avoid using compounds that damage the elements of the system, that do not cause corrosion, for example.
These substances or compounds should always be applied following the instructions of the supplier or manufacturer: with sprinkler, with cloth, directly, diluted, etc., in this way we will avoid or reduce corrosion damage, just to mention an example.

When this type of cleaning is done we must clean all the components of the system, that is, the equipment (UMAs, fan & coil, interior evaporators such as a minisplit, etc.) the ducts and the diffusers.

The purpose of this type of cleaning is to leave the system in optimal operating conditions, referring only to cleaning, free of dust and substances that can harm the health of users. So if necessary we must use substances that eliminate biological contaminants, probably this type of compounds should be applied in the form of nebulization directly to the equipment or the pipeline network, this we call disinfection of the system.

Verify clean and safe air supply
Once the system is clean it will be necessary to ensure that clean and safe air is provided during the operation, and for this we will use two types of components:
• Passives that are those that only act when they come into contact with the air and only in the place where they are installed
• Actives that act and travel with the movement of air

Liabilities
Physical filters. In relation to this component, the suggestion is that the system be provided with the highest efficiency filter with which the equipment can operate, if your equipment can only work with MERV-8 filters or only with very low efficiency filters, do not worry, you have alternatives to improve air quality, but it is very important that you install the physical filter and follow the proper procedure for its replacement or cleaning whenever necessary.

- Publicidad -

During this time of pandemic, much has been said or written about HEPA filters as a great solution and this has generated many questions about it, so I will briefly expose, and I hope clearly, what the use of this type of filters implies:

1. It is very efficient to retain particles that travel in the air of up to 0.3 microns, that is, it can help to mechanically retain the virus that has occupied us so much lately.
2. Not all equipment has the ability to use this type of filter for a very simple reason, the resistance that opposes the passage of air... The so-called pressure drop is very high for most "normal" air conditioning equipment, A high-capacity and clean HEPA filter with a passage speed of 500 ppm opposes an equivalent resistance of 1.5 inches water column, which in some cases is the total pressure differential of the system (equipment and ducts), so for this feature alone it is almost impossible to use it in trading systems.
3. In case the equipment does have the capacity (power) for the use of these filters, it will be necessary to make a modification in the equipment where they will be installed so that they are mounted. Additionally, it is highly recommended to install a pressure gauge that allows monitoring the degree of saturation of the filter for timely change.
4. It is possible to use these filters in almost any system if you add a filter bank that has a fan with the ability to overcome the pressure drop caused by the filter.

But, the most important thing is what use is going to be given to the HEPA filter? If we are going to install it in the outdoor air intake, this level of filtration is not necessary, because biological contaminants or pathogens in aerosol are dispersed very easily in the outside air and very difficult to reach the concentration (which is called viral load), which represents a health risk. On the other hand, if we are going to use it to recirculate the air if it is a good solution, but we must consider that this filter will be filled with pathogens and therefore its change must be done with all the due precautions.

Chemical filters
These types of filters are used to remove contaminants in the gas phase or some aerosols, usually activated carbon, but other substances that have the ability to react with contaminants are also used. The way these filters work is when they oppose the passage of air so that the compounds you want to remove react and are removed.

UVC Emitters
These are also passive because they only act when air passes through their location and is the only opportunity to remove biological load. When using this disinfectant or purifier element, the most important aspect is to calculate the appropriate radiation dose to eliminate the pathogen or pathogens that we know or assume are traveling in the air, so it is necessary to know the airflow and radiation capacity of the emitter.

- Assets: They are those elements that are produced or generated at some point in the system (inside the equipment or in the ducts) and that are transported in the air stream and their action is during their transfer or once they are "discharged" in the enclosure that is conditioned.

- Ions: There are equipment called ionizers whose operation consists of the production of ions and there are those that only produce negative ions (most pollutants have a positive charge), but there are those that produce negative and positive ions (therefore they cover the entire spectrum of pollutants). These devices are installed somewhere in the system and continuously produce ions that are incorporated into the air and during the journey they eliminate the contaminants (they react electronically) some of the ions do not "meet" with any contaminant in the path and are discharged into the enclosure that is conditioned and that is where they act on the contaminants.

- Aerosols: It is common for some applications to use aerosols of chemical substances to remove contaminants. In the same way that ionizers, these devices are installed somewhere in the system and inject into the air stream the aerosol they are producing, usually this production is not continuous and is programmed by time intervals depending on the desired effect and the reactive capacity of the compounds used, the objective is not to cause damage to the health of the occupants. A good example of these devices are Ozonizers or Ozone generators.

- Photocatalyzing: This is a technology that is based on the reactive principle of light or UV radiation, from the use of a UVC emitter encapsulated in a cell coated with hygroscopic material, a reaction is induced that decomposes the oxygen molecules (O2), separating the two atoms which immediately react with the water molecules that are concentrated in the surrounding air by the effect of the hygroscopic material in the form of steam (moisture) and this generates molecules of hydrogen peroxide (hydrogen peroxide) which is a powerful oxidant with the ability to eliminate a huge amount of contaminants including organic (pathogens). These H2O2 molecules, like all active compounds, travel in the air and react with pollutants by removing them.

In conclusion, disinfecting air conditioning systems requires two actions: the first is the prior cleaning of the system. and the second is to provide the system with elements that eliminate pathogens from the air being conditioned.

* Carolina González is the Regional Sales Manager of Johnson Controls Mexico.

Duván Chaverra Agudelo
Duván Chaverra AgudeloEmail: [email protected]
Jefe Editorial en Latin Press, Inc,.
Comunicador Social y Periodista con experiencia de más de 16 años en medios de comunicación. Apasionado por la tecnología y por esta industria.

No comments

• If you're already registered, please log in first. Your email will not be published.

Leave your comment

In reply to Some User
Climate comfort meets efficiency and environmental sustainability in a Caribbean mall

Climate comfort meets efficiency and environmental sustainability in a Caribbean mall

Colombia. It recently began the installation of a modern air conditioning system, parking lot ventilation and solar energy in the Buenavista Shopping Center, in the city of Barranquilla.

AHRI Latam announces LBNL call for Mexican HVAC manufacturers

AHRI Latam announces LBNL call for Mexican HVAC manufacturers

Mexico. Lawrence Berkeley National Laboratory (LBNL) is leading an initiative to evaluate opportunities for the advancement of energy-efficient cooling technologies in the country.

Mitsubishi Electric and AWS sign memorandum of understanding

Mitsubishi Electric and AWS sign memorandum of understanding

International. In this way, Mitsubishi Electric Corporation and Amazon Web Services (AWS) will work together in cloud services and data centers.

Advansor to launch a plug-and-play reversible CO2 heat pump

Advansor to launch a plug-and-play reversible CO2 heat pump

International. Advansor's new solution seeks to position itself as a sustainable alternative to heating systems based on fossil fuels.

Emergent Cold LatAm obtains sustainable certification in Central America

Emergent Cold LatAm obtains sustainable certification in Central America

Guatemala. Emergent Cold Latin America has obtained a new EDGE Advanced certification for sustainable construction, this time for its unit in the Guatemalan town of Palín.

Reliable Controls launches new controller for automation systems

Reliable Controls launches new controller for automation systems

International. The company Reliable Controls has specified that it is the MS/TP model corresponding to its RC-FLEXone BACnet building controller.

Air conditioning for cancer patients: a success story

Air conditioning for cancer patients: a success story

Mexico. The optimization of air conditioning systems in a hospital has become a crucial factor for the well-being of patients and medical staff.

Vertiv and Compass Datacenter develop combined air and liquid cooling system

Vertiv and Compass Datacenter develop combined air and liquid cooling system

International. Vertiv and Compass Datacenters announced a collaboration to develop the first-of-its-kind solution that will facilitate future AI deployments.

Thermostats for BACnet networks

Thermostats for BACnet networks

Contemporary ControlsThe BASstat series of communicating thermostats produced by Contemporary Controls provides seamless integration into BACnet/IP (Wi-Fi) or BACnet MS/TP (EIA-485) networks.

Condensate pumps

Condensate pumps

HartellPlenum-rated condensate pumps are a Hartell solution for ventilation areas and air distribution chambers, backed by decades of proven performance. In addition, these pumps improve the safety...

Free Subscription
SUBSCRIBE TO OUR NEWSLETTER
DO YOU NEED A SERVICE OR PRODUCT QUOTE?
LASTEST INTERVIEWS
SITE SPONSORS










LASTEST NEWSLETTER
Ultimo Info-Boletin