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.
An analysis of energy-efficient light fittings and lighting controls
Electric lighting is one of the major energy consuming items in many non-domestic buildings. Using appropriate energy-efficient light fittings with dimming controls and proper daylighting schemes can help reduce the electrical demand and contribute to visual comfort and green building development. This paper presents a study on the energy and lighting performances for energy-efficient fluorescent lamps associated with electronic ballasts and high frequency photoelectric dimming controls installed in a school building. Electricity expenditures and indoor illuminance levels for a workshop and a classroom employing high frequency dimming controls were analyzed. Simple prediction methods were used to illustrate the lighting savings. The findings provide the operational and performance information, which would be applicable to other spaces with similar building layouts and lighting schemes.
Potential energy saving for a side-lit room using daylight-linked fluorescent lamp installations
The high frequency (HF) electronic ballast has been replacing the conventional magnetic ballast for operating fluorescent lamps. It has the advantage of low energy consumption, running the lamps free from stroboscopic effects, low noise production, being light weight and allowing the lamps to be dimmed. This study shows that for a cellular office at the perimeter of a building lit by a dimmable HF electronic ballast lighting, about 40% of the lighting energy could be saved under Hong Kong’s daylight conditions. A saving of 40% at the perimeter amounts to an overall lighting energy saving of about 10% if the perimeter area is about one quarter of the total floor area. Lighting energy normally accounts for about 30% of the total energy consumption for office buildings. For a shallow plan office building, the amount of saving using a daylight linked system could be significant.