Nov 03, 2021

Reimagining air conditioning systems: New solutions that are a breath of fresh air!

  • infrastructure
  • air conditioning

History, as the cliché goes, often repeats itself. Over the course of centuries, every pandemic has irreversibly changed the way we interact and engage with our environments, be they natural or human-made. After a cholera pandemic in France in 1848, Napoleon III decided to rebuild Paris to create healthier neighbourhoods. The city was redesigned to bring air and sunlight to the dense urban grid and over 12,000 buildings were demolished while an elaborate sewage system was constructed with larger and wider ducts and an innovative cleaning system for greater hygiene. 

In the context of the current COVID-19 pandemic, the same hygiene revolution that took place in civic sanitation in the 19th century—with better water pipes and new and extensive sewage removal systems—needs to be replicated across ventilation systems to overcome the current situation and allow students, academics, professionals and employees to gradually head back to classrooms, campuses, studios and offices.

Within such spaces, Heating, Ventilation and Air Conditioning (HVAC) systems are squarely in the crosshairs given recent scientific evidence about the spread of COVID-19 via microscopic airborne particles and contaminated aerosol droplets through these units, especially if systems are not well-maintained.

Creating Safe Workspaces

Within the multiple business units at Godrej & Boyce (G&B), the attempt over the past 18 months has been to build and adopt a slew of initiatives that focus on people and are intended to make the working environment safer for all. Among the many projects undertaken, upgrading air-conditioning systems was accorded top priority to minimize airborne transmission of any potential infections or viruses.

While there are several ready-to-implement HVAC solutions available, they are often not a realistic option for existing air-conditioning systems as they call for a complete overhaul. It is not easy to retrofit them to existing Air Handling Units (AHUs).

Godrej & Boyce took this challenge as an opportunity to innovate and assemble a custom-built solution that could be implemented across manufacturing plants and other workspaces. The results have been impressive with design and execution costs that are 50% lower compared to other upgrade solutions.

The solution has been analyzed by accredited laboratory experts who assessed both pre and post numbers. The system was measured against surrogate variables like particulate matter, bacterial and fungal counts and found to have significant reduction in fine particles and microbes (at rest condition), which are responsible for transmission and spread of viruses through air conditioning.

Crafting A Bespoke Solution

The custom solution was aimed at addressing four primary areas: filtration efficacy, neutralization of potential fungal or bacterial agents, infusion of fresh air into the system and advanced alternatives for deep cleaning of air distribution systems.

Filtration efficacy was enhanced by introducing and using three filters—MERV 13, MERV 8 and MERV 5, as opposed to only the MERV 7 filter—to reduce particle concentration and infection risks. While MERV 13 is proven to reduce influenza infections by nearly 14% in comparison with MERV 7, the additional filters help improve the life of the MERV 13 filter.  

Filtration can limit the entry of possible microbes and pathogens, but it cannot destroy them. The second part of the solution, therefore, was aimed at neutralizing the presence of these disease-causing agents in the first place.

Based on the recommendations of leading professional institutions in India & abroad, we opted for the required concentration of Ultraviolet Germicidal Irradiation (UVGI) to destroy micro-organisms such as viruses, bacteria and moulds.

The third part of the solution focused on the modification of fresh air supply and improved air recirculation. Fresh air is proven to be a natural disinfectant with rich natural oxidant properties. A humidity level between 40-70% and temperature between 24°C to 27°C are ideal to prevent the proliferation of viruses. Our revamped fresh air dampers have additionally been integrated with MERV 5 filters. The system has also been reconfigured to ensure higher recirculation rates thereby enhancing filtration.

The final part of the solution involved a deep cleaning mechanism for air ducts that are known to be among the most contaminated parts of a central air-conditioning system if not cleaned properly. Robotic cleaning of air ducts has been integrated into the solution to eliminate particulate contaminants and improve the life and efficacy of the entire unit.

The addition of filtration and UVGI do result in an increase in energy consumption due to UV and fan static. But since UV reduces microbe concentration on AHU coils, it also improves the rate of thermal transfer, eventually resulting in energy savings by 4-5%.

The revamped solution has been tested at G&B’s facilities and is now in the process of being implemented across 100+ AC systems in the organization across the country.

For the team that built the solution from scratch, the learning curve has been significant. Apart from technical learnings, it was important to adapt and drive change across the organization, and critically re-examine systems in use to ensure they remained harmonious with the environment around.

As we start unlocking the new normal, organizations will need to reassess their built environments to create workspaces that deliver a cleaner and virus-free future for their people.

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