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ASHRAE position paper on post epidemic HVAC, it's time to reconsider Giacomini RADIANT SYSTEMS


This paper explains some of the many strategies that are believed to be effective for reducing the risk of dissemination of infectious aerosols through heating, ventilating, and air-conditioning systems in buildings and transportation environments…Giacomini went beyond and shows how all these strategies could be unnecessary if using RADIANT SYSTEMS.

1. Air flows control: as a matter of fact, even the most robust HVAC system cannot control all airflows and completely prevent dissemination of an infectious aerosol or disease transmission by droplets or aerosols…it will be easier to control if the system itself has less airflow which is one of the strengths of RADIANT SYSTEMS.

2. Increase outdoor air ventilation: it goes beyond random opening of windows and must be engineered intentionally to achieve ventilation strategies and thereby reduce risk from infectious aerosols. However, such buildings will be more affected by local outdoor air quality, including the level of allergens and pollutants within the outdoor air, varying temperature and humidity conditions, and flying insects…instead, using RADIANT SYSTEM, there is no recirculated air therefore there is no need to increase the outdoor air ventilation.

3. Filtration cannot totally eliminate all risk of transmission, even using highly efficient particle filtration, it can still pose risk of airborne particulates transmission because many other factors besides infectious aerosol concentration contribute to disease transmission…using RADIANT SYSTEM doesn’t involve air flow thus there is no need of filter for central cooling/heating, except for fresh air supply which only requires ordinary filter for outdoor pollutants.

4. The entire ultraviolet (UV) spectrum can kill or inactivate microorganisms, but UV-C energy (in the wavelengths from 200 to 280 nm) provides the most germicidal effect, with 265 nm being the optimum wavelength.…but it can penetrate the very outer surfaces of the eyes and skin, with the eyes being most susceptible to damage!

5. Personalized ventilation systems that provide local exhaust source control and/or supply 100% outdoor, may offer protection against exposure to contaminated air. However, there are no known epidemiological studies that demonstrate a reduction in infectious disease transmission.

6. HVAC systems can be designed to control relative humidity (RH); controlling RH reduces transmission of certain airborne infectious organisms, HVAC designers must carefully consider room temperature and RH…the most unfavorable survival for microorganisms when the RH is between 40% and 60%. In case of RADIANT SYSTEM, it is usually coupled with DOAS (Dedicated Outdoor Air System), RH and temperature control are a typical practice. This equipment can supply constant air temperature and RH (relative humidity) because it is not pre-mixed with recirculated air (AKA exhaust air or return air) hence the word dedicated.

Buildings and HVAC system will change after the pandemic, it will be the occasion to reconsider innovative, healthy heating and cooling systems: GIACOMINI RADIANT SYSTEMS!