Cruise Ships have been hit hard by COVID-19 and increasingly seek clean disinfected air to attract passengers and regain the bookings that generate revenue. One of the most cost-effective and proven solutions for disinfecting airborne pathogens is the integration of an array of linear Ultraviolet-C (UVC) lamps to both clean the Coil and clean the Air on the Duct supply side.

The sample solution below is for a large size Air Handling Unit (AHU) with the Coil, Plenum, primary Duct, and air flow illustrated in the figures.

Status Quo System: (Pathogens pass through the Coil into the Plenum and Ducts.)

Elevation of Coil (left) Cross Section of Plenum (right) feeding into Ducts

large plenum for HVAC

Upgraded System with (24) high power UVC lamps installed downstream from the Coil (This cleans the COIL for energy savings and cleans the AIR by maximizing pathogen irradiation in the DUCTS.)

uvc  in plenum

This example above is for a Cruise Ship with multiple air handling units. This particular AHU-1 has three rows of two coils that are each 8’ wide x 3.5’ tall. The six coils are stacked three high in the plenum that is 16’ wide x 11.5’ tall. The CFM is 73,600 and the approximate square footage of the conditioned area for this ACH-1 is 60,000 SF.

Coil + Air Disinfection UVC System:

The PV-AUV-CK Series is a modular system (like an Erector Set – known perhaps to many of you who grew up before online games). The modular system is assembled on-site and includes the following:

(3) PV-AUV-CK-8 – $4,200 (Electrical Enclosures with 8 ballasts @ $1,400 each)

(24) PV-AUV-GSL-48 lamps – $3,480 ($145 each)

(24) 30 ft lamp cables – $1,800 ($75 each with SureSeal connections)

(48) lamp clamps – $480 (2 per lamp @ $10 each)

(2) switches – $170 ($85 each)

(2) warning signs $20 ($10 each)

Equipment Cost: $10,150

Highlights: For this air handler each of the (24) UVC lamps are 48” linear “tube” modules. Given the 73,600 CFM and the plenum size of (16′ x 11.5′ = 184 SF), the air velocity is 400 feet per minute in the plenum (73,600 CFM / 184 SF).

24 lamps effectively clean the coil and provide the adequate dose of ultraviolet irradiation to also clean the air. Dose is based on time, intensity, and distance. Each of the (24) 48″ high powered UVC lamps is 119 watts, for a total of 2,856 watts. The resulting dosage is 88,250 μW·s/cm2 (micro-Watt seconds per square centimeter), which is also expressed as microjoules per square centimeter or 88.25 joules per square centimeter. The key with this system is to set the lamps on the downstream supply side far enough away from the coils so that they can clean the air on both sides of the lamps. The ideal distance from the coil is 18″ (in this case with the plenum length of 6′ along the path of air flow). The longer the pass through “purge zone” the better, since the air is moving fast, and time is a factor of dosage.

Equipment + Installation Costs: The cost of the equipment $10,150 / 60,000 SF of conditioned space = $0.17 per SF. Installation labor for a system this size could involve two technicians for two days, including commissioning, measurement and verification. Adding an allowance of about $4,000 for installation brings the installed cost to about $14,000 / 60,000 SF = $.023 / SF.

Annual Electricity Costs: For a 24/7 facility, 2,856 watts / 1,000 x 8,760 annual hours = 25,018kWh. At the US average of $0.11/kWh, the annual operating cost = $2,752. With 60,000 square feet of conditioned space, this translates to 4.5 cents per SF per year to have disinfected air. Many Cruise Ships are significantly larger than 60,000, and this example of the Air Handling Unit (ACH) solution is just one of multiple ACHs.

Lamp Replacement Costs: The UVC lamps last for 17,000 hours, which is just over 2 years at 24/7. The cost to replace the (24) lamps is $3,480, which is $1,740 / yr. With 60,000 square feet of conditioned space, this translates to an added 3 cents per SF. The combination of electricity and lamp replacements adds up to 7.5 cents per SF per year to have disinfected air.

24/7 Operation of Cruise Ships:  The following information is to give Cruise Ship owners and operators perspective on the impact of turning off the UVC during service downtime. Each time UVC lamps are turned off or on, they lose an average of 4 hours of life. So, it is definitely not recommended to synchronize the UVC with the fan motor. The UVC lamps have a 17,000 life. With 8,760 hours per year, this translates to 2 years of continuous operation.

Energy Savings from Coil Cleaning: The energy savings is typically a function of the age and condition of the Coils. Older systems (e.g. 6 to 10 years old) may generate return on investment (ROI) in under 2 years, and newer and cleaner systems may generate less annual savings extending the ROI up to 5 years or longer. The ultraviolet ROI also takes into account the reduction in maintenance time and materials needed to clean the coils. At a US average of $1.34 / SF for commercial electricity and 10% for cooling, $0.134 is a placeholder for cooling costs per SF. Clean coils can save between 5% – 15%. An average of 10% savings on $0.134 = $0.013 (one and a third cents) / SF per year. For a 24/7 facility this number could go up by more than a factor of two, yielding 2.6 cents / SF / yr. The energy savings almost covers the annualized cost of UVC lamp replacements.

Utility Rebates, Incentives, and $0 Upfront Cost Programs: Many utility companies offer Commercial and Industrial (C&I) incentives for energy savings based on annual kWh saved. Given that COVID-19 has cost the US taxpayers multiple trillions of dollars, we expect to see incentives to disinfect air from federal or state agencies to help reduce the risk of another pandemic. Purge Virus works with each account to identify the most relevant incentives and also provide $0 upfront cost programs through strategic financing partners. Our partners have approved the UVC technology for monthly payment plans, subject to credit review on 3, 4, and 5 year terms.

KEY SPECIFICATIONS and PRICING – See the Technologies page.

germicidal UV light

We welcome the opportunity to provide a technology recommendation and budget proposal based on the size of your AHU plenum(s), trunk duct(s) and CFM. The “GET STARTED” link to the data sheet is a fast and easy way to let us help show you different disinfection options.

UVC for hotels

Market Traction to Date:

To date other types of businesses and property types have undertaken germicidal disinfection with ultraviolet light. Certain applications are relevant today more than ever for hotels. Since the second half of the 20th century, one of our US production partners has manufactured more than 50,000 germicidal UV light devices. The client list is extensive, and here are just a few examples of major accounts:

Institutions: Infectious Disease Research Institute

Healthcare: New York State Department of Health, Albert Einstein Medical Center, Burbank Hospital, Children′s Hospital Medical Center of Boston, Methodist Healthcare of San Antonio

Food/Beverage: Safeway Stores, Anheuser-Busch, Campbell Soup, Coca-Cola, Pepsi Cola, Del Monte, Dr. Pepper/7-Up, General Foods, Gerber Products, Guinness, Heinz, Hershey’s, Kraft, M&M/Mars, Minute Maid, Ralston Purina, Pepperidge Farms

Education: Princeton University, Cornell University, Johns Hopkins University, Ohio State University

Pharma: Merck, Bristol-Myers Squibb, Eli Lilly

US Government: US Army, Air Force and Naval Hospitals, US Veterans Administration Hospitals, US Department of Agriculture, US Food & Drug Administration