CONSIDERATION FOR MERV13+ FILTER INSTALLATION, IF THE VIRUS CAN TRAVEL FROM THE OCCUPIED SPACE TO THE HVAC MIXING PLENUM. CONSIDERING THE TIMING ISSUE, IT MAY BE WISE TO INSTALL MERV 13+ FILTERS, BUT STILL RESPECT CLIMATE CHANGE ENERGY CONCERNS. “W” SAMPLE HVAC “X” 100% OSA & MERV13+ “Y” OSA ABOVE CODE & MERV13+ “Z” OSA AT CODE & MERV13+ VARIABLE MIXED AIR MAXIMUM ENERGY USE ADDED ENERGY USE OVER NORMAL HEAT ENERGY USE NORMAL FAN HP AS DESIGNED SUPLY FAN HP INCREASED SUPPLY FAN HP INCREASED RETURN FAN HP INCREASED OSA EX. AIR OSA EX. AIR OSA EX. AIR OSA EX. AIR (NO VIRUS?) (VIRUS?) (NO VIRUS?) (VIRUS?) (NO VIRUS?) (VIRUS?) (NO VIRUS?) (VIRUS?) MIXING MIXING MIXING MIXING A DAMPERS B A DAMPERS B A DAMPERS B A DAMPERS B MIXING C MIXING C MIXING C MIXING C PLENUM PLENUM PLENUM PLENUM EXISTING NEW NEW EXISTING FILTERS MERV13+ MERV13+ FILTERS SUPPLY RET. FILTERS SUPPLY RET. FILTERS SUPPLY RET. SUPPLY RET. FAN FAN FAN FAN FAN FAN FAN FAN HP “N” HP “O” HP “N +” HP “O” HP “N +” HP “O” HP “N” HP “O +” NEW HEATING HEATING HEATING HEATING MERV13+ FUNCTION FUNCTION FUNCTION FUNCTION FILTERS D E D E D E D E “W” “X” “Y” “Z” F G H F G H F G H F G H NOTES: OSA-- (Outdoor Air), EX.-- (Exhaust air), RET..—(return), HP—(horse power) RED arrows are suspected virus travel routes. Darker blue arrows are OSA. Lighter blue arrows are mixed air. Orange arrows are heated supply air. 1) 2) The live virus transmission issue must be solved with minimum negative impact on Climate Change via added GHG, considering extra energy requirements. Virus airborne travel from G to H is likely based on case studies; however, I’m unaware of case studies proving virus travel from E to C. If A and C contain no live virus, D will be virusfree, whether on 100% OSA or full recirculation. In this case the problem cannot be solved with alterations at the fan system, but in the occupied space. 3) If the live virus can be recirculated as per example “W” and if the upgraded MERV13+ filters can capture the live virus, Merv13+ filter installation should be considered. 4) Example “X” has MERV13+ filters, clean OSA and exhausts 100% at B. This will be extremely expensive, increasing Climate Change and most systems cannot do this in cold weather. 5) Example “Y” increases the OSA above current minimum ventilation code requirements and with no load analyzing logic has the same negative impact as “X”, but not quite as severe. 6) Example “Y” could maintain current code levels and conservation logic if the live virus can travel to C and the MERV13+ filters can remove the live virus from the air. 7) Example “Z” MERV13+ filters capture the live virus, preventing it from entering the mixing plenum, allowing HVAC conservation design to continue, supporting Climate Change reduction. 8) The MERV13+ filters have a greater pressure drop than existing filters; therefore, will require more fan power (more electricity) to maintain equal airflow as existing arrangements. 9) Increasing the OSA intake in cold weather will tend to reduce the indoor relative humidity, which benefits the virus and is detrimental to humans. 10) If the live virus currently cannot travel from E to C, then D has always been virus-free. If the public believes that better filters and more OSA significantly solved the problem, when D is actually the same, the false sense of security may cause more careless activities in other protective measures. This could make our situation worse. 11) The MERV13+ filters, if required, may require new filter racks and spacing may be an issue in “Y”, possibly making “Z” a more practical location for new MERV13+ filters. . 11.204
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