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.
High performance incandescent lighting by Arny
The efficiency of incandescent light bulbs (ILBs) is inherently very low due to significant emission at infrared wavelengths, diminishing its market share rapidly. ILBs with cold-side filters that transmit visible light but reflect infrared radiation back to the filament can surpass state-of-the-art light-emitting diodes (LEDs) in both efficiency and light quality (color rending index; CRI). However, practical challenges such as filter and filament thermal stability, filament evaporation and imperfect geometrical alignment (view factor) between the filament and cold-side filter can limit the maximum achievable efficiency and significantly reduce the effectiveness of cold-side filters. In this thesis, we first present a review of existing approaches to improve the efficiency of ILBs such as selective filters and emitters for incandescent lighting. We highlight different challenges in achieving an efficient and long lasting bulb, and discuss previous approaches used to address these challenges in ILBs. We then present the modelling framework as well as the experimental setup and methods use throughout the thesis to study these problems. Second, we show that the effect of imperfect view factor between the filament and filter on the system efficiency can be minimized by combining a cold-side optical filter with a selective emitter. We experimentally and theoretically demonstrate energy savings of up to 67% compared to a bare tungsten emitter at 2000 K, representing a 34% improvement over a bare tungsten filament with a filter. Our work suggests that this approach can be competitive with LEDs in terms of luminous efficiency as well as CRI
Study on Electrical Explosion Mechanism and Ignition Characteristics of Copper and Aluminum Powder Under Ignition Solid Propellant
In order to study the characteristic of the electrical explosion of copper and aluminum powders, a multilayer generator was designed, an experimental system was set up, and the parameters of metal powder electrical explosion were measured and analyzed. The results show that the duration of the electrical explosion process increases significantly due to the addition of metal powder. The duration of aluminum powder electrical explosion jet flow is ~86.36 ms due to its self-sustained combustion, which releases a large amount of energy, and a small fraction of aluminum powder particles is not burned. The duration of copper powder electrical explosion jet flow is ~15.84 ms, and most of the copper powder particles are in the solid state. The current pause process is absent; instead, the first discharge process is connected to the second discharge process. The effect of copper powder on the first discharge process is greater than that of aluminum powder. Furthermore, the ignition ability of copper powder electrical explosion to solid propellant is stronger than that of aluminum powder in a closed bomb experiment. These results are indubitably meaningful for the application of metal powder electrical explosion and ignition of solid propellant in an electrothermal chemical gun.