Cost–benefit analysis of retrofit of high-intensity discharge factory lighting with energy-saving alternatives
Due to increased concern about overall energy costs and the appearance of efficient and inexpensive lighting system alternatives, factories and plants with high-intensity discharge (HID) lighting are forced to consider retrofit with more modern, energy-efficient lighting. The decision is complicated from an economic perspective, and there is a lack of information readily available on the topic. This study provides an analysis of the replacement by retrofit of common probe-start metal halide and high-pressure sodium industrial lighting systems. Retrofit options considered include the more recent pulse-start metal halide lamps and a range of T5 high output and T8 fluorescent lamp configurations. Recent data on lighting system pricing, labor and energy costs, and time required for tasks are reported. The results generated include savings, payback period, and net present value for many retrofit options, as well as the change in energy consumption, carbon footprint, and lumen output for each retrofit. Effects of varying rate of return and daily duration of operation are considered. Based on change in lumen output, payback period, net present value, and comparison of lighting quality, one or two options are recommended from the overall retrofit options considered. A fluorescent retrofit is recommended for each of the HID initial scenarios considered. The payback period is no more than 3 years in any recommended case. The focus of this study is on the potential energy and cost savings, and some proposed solutions may, or may not, be acceptable due to lack of illuminance uniformity.
Active fume hood sash height monitoring with audible feedback
Abstract Fume hoods in laboratories consume the energy equivalent of up to four American households per hood; however, closing a modern hood’s sash completely can save up to 75% of that energy. Past efforts have attempted to harness this potential energy reduction by reminding users to close the sash when a hood is not in use. In this work, we developed a device to measure the efficacy of these energy-saving methods. The device records the position of the sash and detects motion to determine whether a user is present, and, when fitted with a piezoelectric buzzer, can audibly alert users to close the sash when not in use. We installed this device in laboratories to quantify the energy and cost savings resulting from real-time audible feedback and found that the alarm reduced wasted energy by 87 to 98%. In addition, the platform demonstrated here can be used to quantitatively test other energy-saving methods that rely on user behavioral change in future work.
The possibility of pulsed laser deposited organic thin films for light-emitting diodes
Organic films of Alq 3 and TPD, which stand as successful materials used in organic electroluminescence applications, were deposited by the pulsed laser deposition method as an alternative to traditional thermal evaporation and spin coating techniques. An organic pellet target was ablated with two wavelengths, 532 and 355 nm, of a Q-switched Nd/YAG laser at a base pressure of 2×10 -5 torr. Films on slide glasses were evaluated by photoluminescence, AFM, absorption spectra, and XRD to find the possibility of those films acting as organic light-emitting diodes. When 355 nm laser irradiation was used for deposition, Alq 3 and TPD films had negligible voids and were less stressed than thermal films. Even though we used a highly stressed Alq 3 pellet target, the Alq 3 film prepared by pulsed laser deposition showed a preferential structure similar to the thermally evaporated Alq 3 film. Films deposited in this experiment were more amorphous than the films fabricated by excimer lasers.