High-quality street lighting improves visual perception of the road and provides for a significant decrease in the number of road accidents. It has been established that the total number of accidents can be reduced by 30% for national roads and by 45% for especially hazard areas (e.g., at intersections). Doubling of the average luminance of the road surface significantly reduces the number of accidents in the dark and twilight. Sufficient street lighting contributes to: reducing electricity consumption; decreasing operating costs; improving the environmental situation; promoting business, tourism and investment activity; decreasing the number of criminal offenses. The analysis of recent research and publications helped choose the best European practices which can be used to improve the outdoor lighting in Ukraine. The street lighting network is continuously growing and being modernized. Different types of light sources are being used in the network to illuminate the city. Today, high-pressure lamps (HPS) are leading. They are increasingly replaced by LED light sources. Not a small share is accounted for by metal-halide lamps. The smallest number of light sources in the street lighting system, high-pressure mercury and compact fluorescent lamps (CFLs). To increase the efficiency of the street lighting system and reduce energy consumption for its operation, measures for its reconstruction and modernization are required. For this purpose, it is necessary to address the following problems: high level of obsolescence and physical wear and tear of system elements; inefficient use and high losses of electricity at the stages of transportation and consumption, due to the use of obsolete and worn-out equipment; suboptimal distribution of the utility capacity, which leads to ineffective use of the existing lighting system; low efficiency of the street lighting control system, due to the lack of electric meters and remote monitoring and control of the street lighting. Introduction of energy-saving types of light sources is one of the ways to modernize the existing street lighting system. It is necessary to replace old lighting fixtures, which have already exhausted their life span, by new energy-saving light sources (replace CFLs by LEDs), use automatic control systems. All this in turn will help reduce energy costs by 60%. To improve energy efficiency of the street lighting system, it is also recommended to carryout the replacement of electromagnetic ballasts by electronic ones. The employment of electronic ballasts, e.g., in case of using HPS 250 lamps, allows to save approximately 255 kWh/year. Considering that the price per kW of electric energy is UAH 2.68, one luminaire helps save the amount of UAH 683.4 per year.
Analysis of operating conditions of a cooling installation with carbon dioxide
