Challenges Presented by Covid-19 in Terms of Air Quality and Ventilation
As many countries now enter a post pandemic phase, both businesses and the public will have to adapt their behavior to live with this virus while it remains active in the community. For the Hospitality sector in addition to the challenges posed by the constraints of social distancing, it will be important to understand the measures that will have to be taken to ensure that both staff and guests feel safe and are relaxed about returning to their favored Hotel or Restaurant or indeed work place. These factors that will also have an impact on retail and commercial office environments for both staff and consumers. Therefore, across all sectors of hospitality and commercial environments it is important to understand how to adapt our building to this new situation. Infection prevention and control is not a focal aspect of hotel and building design, so with the new awareness and concern about disease transmission, now the question is how to adapt the facility’s operations to these new requirements.
The coronavirus can survive on a surface for a period of time from a few hours to a few days. It spreads with a contact on contaminated surfaces and can be transmitted by contact to the ears, eyes or mouth. There is now a growing concern that the virus can spread via airborne transmission. This means that, in the case of this disease, the three main focus areas from a facility management perspective are transmission from person to person, transmission from surfaces and as importantly how the HVAC system can help to reduce the virus spread by mitigating airborne transmission.
New Government Regulations
In an effort to help reduce the spread of the virus, Governments around the world are analysing the effects of improving indoor ventilation to avoid virus spread and are currently creating new regulations which are evolving as new research and recommendations are delivered. Most of the recommendations focus on providing as much fresh air as possible, keeping the exhaust running all the time and maintaining appropriate temperature and humidity levels to create an environment hostile to the virus to survive in.
For example, UK Government has recommended the use of high-efficiency particulate air (HEPA) filtration and opening doors and windows where possible and safe to do so. As per the guideline set by the Indian Government the room temperature should be maintained between 24 °C and 30 °C and maintain a relative humidity between 40% and 70%. The Saudi Government is ensuring that the air-handling units of grand mosques in Mecca and Medina are supplying 100% fresh air with no recirculation. ASHRAE in the US, provide a series of recommendation, including a flushing sequence before and after area running hours.
What effect will these Measures have on Energy Efficiency?
To tackle these new challenges, the following topics and measures has been analyzed in order to understand what can be done and what will be the impact on the building’s energy consumption:
Improving filtration can boost the overall quality of the air, but higher filtration grades bring resistance to the system: the finer the mesh, the more energy it requires to push the air through, which increases the energy consumption of the building.
HEPA filters are probably the only ones that have been shown to remove viruses. High rated MERV filters, typically specified in central air handling units, can remove 90-95% of bacteria and small particles, but not the particles as small as most viruses. A lot of the particles never make it to the air handling units. One proposed solution for those particles is ultraviolet germicidal irradiation (UVGI), which uses short-wave UVC irradiance to kill or deactivate microorganisms. However, there is still no specific evidence of the efficacy of UVC irradiation for coronavirus.
It is believed that the right relative humidity level, ideally between 40-60%, reduces the infectivity of viruses and makes them settle more quickly. However, many existing buildings are not built for higher levels of humidity. Humidification will result in window condensation and increase potential mold growth if not properly controlled and, of course, high energy costs.
Dilution of indoor air with fresh air would minimize the risk of possible airborne viral transmission by reducing the exposure period for any airborne viral aerosols and thus decrease the likelihood for such aerosols to settle on surfaces. Research suggests that the virus will survive on certain surfaces for at least 72 hours and therefore any effort to reduce surface contamination is desirable. .
It is recommended that every air-handling unit that usually runs in recirculation mode should now be set up to run on 100% fresh air wherever it’s possible. This again comes with an energy penalty, as it takes more to cool or heat the air to the right temperature and the equipment would have to be sized to meet higher demand. How much additional energy which is required depends on the geographical location of the building.
It is clear the measures outlined above designed to mitigate virus transference within buildings will have a direct result of increased energy consumption and therefore increased costs. Therefore, it is important to design and introduce new energy management schemes in order to reduce as much as possible the impact of the new operating measures.
These necessary new energy management schemes can be designed and integrated into current systems by way of sensors that monitor the new ventilation regimes while at the same time ensuring each individual building is performing at the optimum energy efficiency level.
The Quimera Energy Efficiency team with its knowledge and Global experience in this field, is dedicated to support our clients in mitigating the ongoing effects of COVID-19 and will assist our in adapting energy management schemes to reduce the risk of coronavirus spreading through the HVAC system and improving the overall air quality within these buildings-while at the same time QEE would be deploying its proven Smart Tech solutions to mitigate the potential increase in energy consumption.
In addition, the holistic approach of the “Monitor & Save” methodology from QEE can provide a monitoring system and create energy conservation measures (ECMs) beyond the HVAC system to ensure the entire building is working at an optimal level, in order to absorb the potential increase in energy consumption due to implementation of recommended measures applied to the HVAC systems.
The retro-commissioning approach in a ESCO model can provide these new energy management solutions for existing buildings by adding new sensors, hardware and our software control in order to mitigate the impact of COVID-19 and keep reducing energy consumption, reduce utility bills and emissions and all at zero cost to our clients.