The healthcare industry has made great progress in implementing strategies that lower risks, improve building efficiency, and reduce carbon footprints. Many measures are geared toward reducing heating and cooling system energy consumption, and recent advances in air cleaning technologies are helping to take these strategies to the next level.
For example, MERV 13 and up systems can clean the air of biologicals, ultra-fine particles, nuisance odors, and volatile organic compounds (VOCs), while substantially reducing energy consumption and operational costs.
Improved indoor air quality
High-efficiency air cleaning systems can improve indoor air quality (IAQ) by improving filtration of:
- Biological contaminants. High-efficiency air cleaners can provide effective control of airborne organisms, including viruses, bacteria, molds, and mold spores. Systems that collect mold spores reduce the risk of potential mold problems by removing mold spores from the air stream, as well as sub-micron particles, which can provide a food source for mold and pathogen growth. Technologies that address biologicals (living airborne organisms) include polarized-media air cleaners, HEPA filters, and ultraviolet germicidal lamps. Some produce Ozone, and some do not.
- Ultrafine particles. High-efficiency air cleaners can remove dangerous, ultra-fine airborne particles, such as particulates, from combustion engine exhaust pulled into buildings from heliports, ambulance bays, and covered loading/unloading zones.
- Odors and VOCs. Issues with odors and/or VOCs will also impact the type of filtration. Medical facilities and assisted-living facilities are common examples of applications where odor and VOC issues can be expected. Today, the most popular technologies that address these gas phase contaminants include polarized-media air cleaners, carbon filters, and photo-catalytic oxidation.
Operating costs savings
Healthcare facilities can find significant operational savings in new air cleaning technologies through:
- Reduced fan horsepower from lower static pressure;
- Reduced maintenance costs from longer service intervals; and
- Reduced disposal costs.
Fan horsepower. Historically, increasing filter efficiency meant increasing energy and operating costs because it takes more fan horsepower to push air through denser filter media. Lower static pressure also corresponds directly to lower brake horsepower. Since brake horsepower drives fan energy, lower static pressure corresponds directly to energy savings.
In a recent amendment within ASHRAE Standard 90.1-2007, a standard has been set for allowable brake horsepower for each type of system and space use. Section 6.5 of the 2007 version of ASHRAE 90.1 (HVAC Air System Design and Control) sets allowances for brake horsepower based upon system type and application. While these allowances can often be difficult to meet with traditional high-efficiency passive filtration, newer advanced air cleaners can help to meet them.
The third largest energy cost item in a healthcare setting is the energy needed to move air through heating and cooling systems. Lowering static pressure is one of the most effective and measurable ways to immediately reduce the total energy used by an HVAC system. Newer active field electronic air cleaners offer relatively low resistance.
In some cases, there can be mid-life pressure drop savings of up to 1.5 inches versus passive, mechanical filters. This allows fans to be designed and selected with lower break horsepower requirements and potentially far less operational energy consumption. For example, in a hospital with 300 filters operating on an average of 0.5 inches lower in pressure drop during use equates to $26,669 in annual energy savings (based on $0.10 per kWh).
Maintenance. Polarized-media filters last longer than conventional passive filtration due to very high dust-holding capacity, often extending change-out intervals from several months to several years and lowering labor, ordering, handling, storage, and disposal costs.
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