# Design and Application of Daylight-Based Lighting Controller on LED Luminaire
## 1 Introduction  
Artificial lighting from luminaire has been an essential part of modern society due to the expansion of urban areas with high-rise building that block the natural lighting, working space that less likely to receive daylight, and night-time activity that required lighting. Thus, the quality of lighting has become directly correlated to the quality of life. This result in large amounts of power consumption in residential, commercial, and industrial sectors delicate to lighting systems. In the case of Thailand, the 2019 energy statistics from the Energy Policy and Planning Office (EPPO) under Thailand's Ministry of Energy [1] show that Thailand's residential and commercial section has power consumption growth at 10.1% and 6.0%, respectively, due to rising consumption in high-rise buildings such as apartments, department stores, hotels, and office buildings. From these statistics, it can be seen that electricity demand has become a challenging issue in Thailand. In addition, power generation from coal power plant could not proceed as scheduled by a power development plan (PDP2015) due to environmental concern from communities around the designated construction project. Therefore, Thailand's heavy reliance on import energy combined with depleted fossil fuel may cause a severe problem in the future in terms of energy security. Hence,the Thai government has formulated a long-term strategic policy to improve energy efficiency and reduce energy consumption entitled \"Energy Efficiency Plan (EEP 2015)\" [2] in order to reduce Energy Intensity (EI) by 30% or around 56,142 ktoe in the next 30 years. This plan includes improving energy efficiency in residential, business, industrial, and other sectors to achieve the designated goal of the master plan. One of the objectives to achieve a reduction in energy intensity is to reduce energy consumption in the building and improve energy efficiency. Energy usage in a building can be divided into a different category according to engineering end-use models. According to the 2012 Commercial Buildings Energy Consumption Survey (CBECS) [3], energy consumption in the heating, ventilation, and air conditioning (HVAC) systems is the largest share of total electricity consumption at 32%, followed by miscellaneous electric loads (MELs) at 18%. The lighting system consumes up to 17% share of energy consumption in a building, while the heat generated from the luminaire can affect the cooling load of HVAC. Evaluation methodologies and mathematical models have obtained the energy profile and forecast of energy consumption on the lighting system by taken many parameters into consideration for accurate assessment, such as daylight [4], the controller [5], and occupant behavior [6]. Thus, it shows that the implementation of energy-saving measured in the lighting system has the potential to reduce a considerable amount of energy consumption and improve the overall energy efficiency of a building. The technology in the illumination have continuously been developed over time from incandescent lamp to fluorescent and then to light-emitting diode (LED) lamp that is currently used in a modern lighting system. In addition, new organic light-emitting diodes (OLEDs) technology has recently emerged as a competent lamp for the future [7; 8]. A comparison between various interior lighting technologies in various aspects such as energy consumption and light characteristics shows that LED has significant advantages over other lighting technologies, especially in the energy requirement for a luminaire. With current technology, luminous efficacy is steadily increased, and installation cost is reduced to a commercially acceptable level [9; 10; 11; 12]. In terms of thermal performance, a comparison between three types of luminaires--fluorescent T8, fluorescent T5, and LED luminaire--shows that fluorescent luminaire both T8 and T5 generated heat at about 73-77% of its rated power. In contrast, LED luminaire generated heat around 87-90% of rated power but could be reduced when LED was dimmed [13].