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Maintenance
Published in Stan Walerczyk, Lighting & Controls: Transitioning to the Future, 2020
Mercury vapor lamps are primarily rated for 24,000 hours, but they usually last considerably longer, getting considerably dimmer over time. Similarly, 20,000-hour rated, standard 400W MH lamps last longer and also get dimmer. If the manufacturers listed longer-rated lives, the mean lumens would be worse than they are now, which is already not very good.
How to Design a Lighting System
Published in Scott C. Dunning, Albert Thumann, Efficient Lighting Applications and Case Studies, 2020
Scott C. Dunning, Albert Thumann
Although, used extensively in the past, mercury vapor lamps are not as popular as other HID sources today due to its relatively low efficacy. However, because of their low cost and long life (16,000 to 24,000 hours), mercury vapor lamps still find some applications.
The Electrical System Audit
Published in Albert Thumann, Terry Niehus, William J. Younger, Handbook of Energy Audits, 2020
Albert Thumann, Terry Niehus, William J. Younger
Mercury vapor lamps find limited use in today’s lighting systems because fluorescent and other high intensity discharge (HID) sources have surpassed them in both lamp efficacy and system efficiency. Typical ratings for mercury vapor lamps range from about 25 to 50 lumens per watt. The primary advantages of mercury lamps are a good range of color, availability, in sizes as low as 30 watts, long life and relatively low cost. However, fluorescent systems are available today which can do many of the jobs mercury used to do and they do it more efficiently. There are still places for mercury vapor lamps in lighting design, but they are becoming fewer as technology advances in fluorescent and higher efficacy HID sources.
Field measurement and modeling of UVC cooling coil irradiation for heating, ventilating, and air conditioning energy use reduction (RP-1738)—Part 2: Energy, indoor air quality, and economic modeling
Published in Science and Technology for the Built Environment, 2018
Joseph Firrantello, William Bahnfleth
Low-pressure mercury vapor lamps produce UV light at 254 nm, which can be used to inactivate microorganisms in water, air, and on surfaces by damaging their DNA. UVGI disinfection, to a first approximation, follows an exponential dose-response relationship (ASHRAE 2016): where S is the surviving fraction of an initial population N0, Nt is the population after time t [s], k [cm2/μW-s] is a microorganism-specific rate constant, and I [μW/cm2] is the average irradiance. Aspects of UVGI theory, technology, and application are reviewed extensively by ASHRAE (2015b, 2016) and Kowalski (2003, 2009).