scholarly journals Analysis of Energy and Cost Performance of Retrofitting Fluorescent Tubes with Compact Fluorescent and Light Emitting Diode Lamps

2020 ◽  
pp. 34-46 ◽  
Author(s):  
J. S. Adeleke ◽  
A. B. Wahab ◽  
E. A. Olanipekun
Keyword(s):  
Light Emitting Diode ◽  
Electricity Consumption ◽  
Poor Performance ◽  
Payback Period ◽  
Optimal Performance ◽  
Light Emitting ◽  
Tertiary Institutions ◽  
Fluorescent Lamps ◽  
Significant Difference ◽  
Compact Fluorescent Lamp

Over the years, visual comfort has been described as a major requirement needed to enhance optimal performance of occupants in any learning environment in tertiary institutions. This is reflected in the poor performance of the commonly used Fluorescent Lamps (FL) occasioned by its constant burn-off, high failure rate and reduced durability. Hence, there is a shift to the adoption of Compact Fluorescent Lamp (CFL) and Light Emitting Diode (LED). This study therefore examined the pattern of electricity consumption involving the adoption of FL, CFL and LED in the purposively selected lecture theatres of Obafemi Awolowo University, Ile-Ife, Nigeria. The study was carried out using energy monitor to obtain the consumption data of the lamps for periodic logging at intervals of 1 hr, 3 hrs, 6 hrs, 12 hrs, 1 day, 7 days, 1 month and 3 months respectively; and also to determine the payback period of each of the lamps. From the data collected, patterns of electricity used, electricity savings were calculated and compared to establish performance potentials of each of the lamps. The study found that there was a significant difference in the pattern of electricity consumption of FLs compared with that of CFLs and LEDs, but a reduced margin existed between CFLs and LED lamps. It showed that the FLs consumed 681.576 kWh, 1619.466 kWh and 5652.432 kWh, CFLs consumed 387.302 kWh, 692.479 kWh and 1936.600 kWh, while LED consumed 294.188 kWh, 426.608 kWh and 1499.015 kWh. There were significant differences in consumption with 43, 47 and 65% reduction in electricity consumption using CFLs while 57, 73 and 73% using LED fittings were obtained. The CFLs performed better in terms of return on investments by having a lower payback period when compared to LED. The study concluded that replacing FL with CFL and LED would be desirable option in order to enhance optimal performance of lecture theatres, but in terms of payback period, it would be beneficial to retrofit FLs with CFLs.

scholarly journals Effectiveness of light emitting diode versus conventional phototherapy in neonatal hyperbilirubinemia: a hospital based observational study

2020 ◽  
Vol 8 (3) ◽  
pp. 1051
Author(s):  
Radheshyam Purkait ◽  
Manik Mondal
Keyword(s):  
Side Effects ◽  
Light Emitting Diode ◽  
Total Duration ◽  
Conventional Group ◽  
Light Sources ◽  
Fluorescent Lamp ◽  
Light Emitting ◽  
Led Phototherapy ◽  
Significant Difference ◽  
Compact Fluorescent Lamp

Background: The most commonly used light sources in the conventional phototherapy units are compact fluorescent lamp (CFL), halogen spotlights and fiberoptic blankets. Recently light emitting diodes (LED) has emerged as better light source for phototherapy and almost replacing all the available conventional light sources. Comparative studies on the efficacy of LED versus conventional phototherapy are limited from India. That is why; this study was undertaken.Methods: 48 neonates of ≥35 weeks gestational age with hyperbilirubinemia were participated in this study. Among them, 24 neonates received conventional phototherapy and rest of them received LED phototherapy. The rate of fall of bilirubin levels at 6 hours and at completion along with total duration of phototherapy in both groups was measured. Results analysed by standard statistical methods.Results: LED phototherapy units showed higher rate of fall in bilirubin at six hrs (LED group: 0.38±0.05 mg/dl/hr versus conventional group: 0.30±0.04 mg/dl/hr, p<0.05) and after completion of therapy (LED group:                      0.32±0.03 mg/dl/hr versus conventional group: 0.26±0.03 mg/dl/hr, p<0.05) compared to conventional group. Significant difference was documented in total duration of phototherapy in LED group (30.8±1.8 hours) when compared to conventional group (34.6±0.7 hours). None of the neonate showed phototherapy failure. Side effects were minimal and comparable in both the groups.Conclusions: The LED phototherapy units are more efficacious in terms of higher rate of fall of bilirubin levels and lesser duration of phototherapy compared to conventional phototherapy units.

Changes in Lighting Source Can Produce Inaccurate Assessment of Visual Poultry Doneness and Induce Consumers To Eat Undercooked Ground Turkey Patties

2019 ◽  
Vol 82 (3) ◽  
pp. 528-534 ◽  
Author(s):  
CURTIS MAUGHAN ◽  
EDGAR CHAMBERS IV ◽  
SANDRIA GODWIN ◽  
DELORES CHAMBERS
Keyword(s):  
Foodborne Pathogens ◽  
Light Emitting Diode ◽  
The United States ◽  
Extrinsic Factors ◽  
Visual Appearance ◽  
Light Emitting ◽  
End Point ◽  
Lighting Conditions ◽  
Compact Fluorescent Lamp ◽  
End Point Temperature

ABSTRACT Undercooked poultry is a potential source of foodborne pathogens, such as Salmonella and Campylobacter. The best way to avoid eating undercooked poultry is to use a food thermometer during cooking. However, consumers who cook poultry often use visual appearance for determining doneness, which relies on extrinsic factors, including lighting conditions. Because the United States recently mandated changes in lighting to promote energy conservation, this study evaluated the effect of lighting sources on consumer perceptions of doneness and willingness to eat cooked poultry patties. Consumers (n = 104) evaluated validated photographs of turkey patties cooked to different end point temperatures (57 to 79°C) and rated the level of perceived doneness and willingness to eat each sample. Evaluations were conducted under different lighting sources: incandescent (60 W, soft white), halogen (43 W, soft white), compact fluorescent lamp (13 W, soft white), light-emitting diode (LED; 10.5 W, soft white), and daylight LED (14 W). Lighting changed perception of doneness and willingness to eat the patties, with some of the energy-efficient options, such as LED and halogen making samples appear more done than they actually were, increasing the willingness to eat undercooked samples. This poses a risk of consuming meat that could contain bacteria not killed by heat treatment. Recent changes in lighting regulations can affect lighting in homes that affects perceptions of poultry doneness, requiring that educators place extra emphasis on the message that properly using a meat thermometer is the only way to ensure meat is cooked to a safe end point temperature.

Discomfort glare caused by white LEDs having different spectral power distributions

2017 ◽  
Vol 50 (6) ◽  
pp. 921-936 ◽  
Author(s):  
WJ Huang ◽  
Y Yang ◽  
M Ronnier Luo
Keyword(s):  
White Light ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
White Leds ◽  
Significant Difference ◽  
Discomfort Glare ◽  
Led Lights ◽  
Green Leds

This paper describes an experiment to investigate discomfort glare caused by white light-emitting diode (LED) lights having different spectral power distributions. It included two groups: a ‘Metamerism’ group and a ‘correlated colour temperatures (CCT)’ group. In the former group, it was found that white lights at 7000 K constructed from different blue LEDs and the same red and green LEDs gave about the same glare perception. In the latter group, there was a significant difference in glare perception between white lights having different CCTs. Finally, glare models, including unified glare rating (UGR) and the newly derived QUGRspd, and mUGRspd models, were tested using the data from the experiment. All of them gave quite accurate predictions of the data.

scholarly journals Evaluation of the bond strength of orthodontic brackets and the degree of polymerisation and microhardness of an orthodontic adhesive using polyvawe light curing unit and varying light densities

2020 ◽  
Vol 23 (4) ◽  
pp. 9p
Author(s):  
Nuri Mert Topbasi ◽  
Yasin Atakan Benkli
Keyword(s):  
Bond Strength ◽  
Light Emitting Diode ◽  
Control Group ◽  
Bond Failure ◽  
Adhesive Resin ◽  
Mean Values ◽  
Light Emitting ◽  
Significant Difference ◽  
Light Curing

Objective: This study evaluates the shear bond strength (SBS) and Vickers micro-hardness (VHN) of the orthodontic adhesive resin Transbond XT using thermocycled samples. The study also measures the degree of cure by poliwave light curing unit Valo. Materials and Methods: 135 brackets were bonded for the SBS test, and 90 disc-shaped orthodontic adhesive resins were prepared for the VHN test. The measurements were taken either immediately or after 500 or 10.0000 thermocycling. The SBS and VHN test data were statistically evaluated using a Two-way ANOVA and Tukey multiple comparison tests. The degree of conversion (DC) was measured by FTIR. Results: The 10-sec polymerized control group (57.08) and the 10.000 termocycled samples (55.96) had the highest VHN scores. On the other hand, the 3 second polymerized and the 10.000 termocycled samples (39.22) had the lowest VHN scores. There was no significant difference in the bracket SBS values between the termocycled and immediate groups. An evaluation of the bond failure surfaces revealed that the ARI scores did not differ between the immediate and the thermo-cycled groups according to the power modes. The FTIR results revealed that the lowest DC was seen in the 3 second light-cured sample. Conclusion: Transbond XT provided sufficient bonding in terms of microhardness and DC under in vitro bracket bonding conditions after 10 and 8 seconds of Poliwave LED curing. However, low mean values were seen in the groups that received Poliwave LED curing for only 3 seconds. KEYWORDSARI score; FTIR; Light-Emitting Diode; Orthodontics; Thermocycling.

scholarly journals Using Movable Light-emitting Diodes for Electricity Savings in a Plant Factory Growing Lettuce

2014 ◽  
Vol 24 (5) ◽  
pp. 546-553 ◽  
Author(s):  
Kun Li ◽  
Qi-Chang Yang ◽  
Yu-Xin Tong ◽  
Ruifeng Cheng
Keyword(s):  
Energy Savings ◽  
Light Emitting Diode ◽  
Electricity Consumption ◽  
Light Emitting ◽  
Light Utilization ◽  
Lettuce Growth ◽  
Left And Right ◽  
Plant Yields ◽  
Butterhead Lettuce ◽  
Main Factor

In this study, the effects of light-emitting diode (LED) panels with different illumination schedules and mounted above butterhead lettuce (Lactuca sativa var. capitata) seedlings on lettuce growth and photosynthesis were examined, and the performance of the vertical and horizontal movable system on energy savings was evaluated. The illumination schedules used were fixed LED [F-LED (four LED panels illuminated the area below)] and movable LED [M-LED (two LED panels moved left and right once per day to illuminate the same area as F-LED)] at distances of 10 and 30 cm above the seedlings. The plant yields were uniform in all LED treatments. The highest light utilization efficiencies and lowest electricity consumption were found for the treatments with irradiation from a shorter distance above the seedlings. The true leaf numbers and ascorbic acid concentrations were the highest in the M-LED and F-LED treatments at a distance above the seedlings of 10 cm, while the leaf lengths and sucrose concentrations in these groups were significantly lower than those in the 30-cm treatment. These results indicate that illumination with M-LED can halve the initial light source input while maintaining yield and that sustained illumination from a shorter distance above the seedlings is the main factor in electricity savings.

scholarly journals A review of leakage current mechanism in nitride based light emitting diode

2016 ◽  
Vol 12 (2) ◽  
Author(s):  
Anati Syahirah Hedzir ◽  
Norasmahan Muridan ◽  
Nurul Fadzlin Hasbullah
Keyword(s):  
Leakage Current ◽  
Light Emitting Diode ◽  
Forward Bias ◽  
Dominant Mechanism ◽  
Light Emitting ◽  
Fluorescent Lamps ◽  
High Bias ◽  
Assisted Tunneling ◽  
Leakage Current Mechanism ◽  
Current Mechanism

We review the dominant mechanism and characteristics of it which gave rise to the existence of forward and reverse leakage current in nitride based light emitting diode (LED). LED is one of the promising device to be used as a lighting source because it does not contain mercury unlike fluorescent lamps. However, the existence of leakage current can affect the reliability and efficiency of LED. Hence, its importance to understand the mechanism that responsible for its existence. The occurrence of leakage current is divided into three main parameters: 1) low bias; 2) medium or high bias; 3) temperature dependence. In low reverse bias, Poole-Frenkel is the dominant mechanism while tunneling is the dominant mechanism in high bias region. Furthermore, in forward bias, defect assisted tunneling is most likely the dominant mechanism. In low forward bias, electrons are the dominant carriers in defect assisted tunneling while in medium forward bias, holes are the dominant carriers.  Moreover, Variable Range Hopping (VRH) is reported to be dominant when the temperature of conduction is below 200K. 

scholarly journals Smart Street Lighting Detecting Vehicle and Pedestrian Movement Aiming for Sustainable Bhutan

2020 ◽  
Vol 9 (3) ◽  
pp. 4276-4281
Keyword(s):  
Light Emitting Diode ◽  
Electrical Energy ◽  
Fluorescent Lamp ◽  
Infrared Source ◽  
Light Emitting ◽  
Underdeveloped Countries ◽  
Global Issue ◽  
High Initial Cost ◽  
Compact Fluorescent Lamp ◽  
And Control

An energy crisis is global issue nowadays. Bhutan however, does not realize it being blessed with good geographical and demographical diversity. It is high time that Bhutan realize the need of energy conservation technique. The electrical energy is wasted unnecessarily which starts from keeping the mobile charger plugged in the socket when not in use to lamps keeping ON in streets throughout day and night. People don’t seem to care but monitoring it for better conservation benefit has become crucial in underdeveloped countries like Bhutan whose source of energy is limited to hydropower only. Wind and solar generations are feasible but the energy cost per unit would be very high due to high initial cost. A case study conducted within the college campus revealed tremendous savings a college can make just by replacing conventional compact fluorescent lamp (CFL) with light emitting diode (LED). Therefore, the best option for Bhutan and Bhutanese people is to take better care of the existing energy sources and use it judiciously. This paper proposes a method to monitor and control the street/compound lighting in a smarter way. The two types of sensors are employed. The light dependent resistor (LDR) is used to monitor the intensity or brightness of surrounding and passive infrared (PIR) sensor is employed for detecting infrared source. The sensor output is processed and monitored by the PIC16F877A microcontroller. Moreover, the incandescent lamp and the compact fluorescent lamp will be replaced by LED lamps. The project aims to reduce power consumption in Bhutan through proposer control of street/compound lighting so as to have better economy of the country by exporting more unit of energy to neighboring country.

DESIGN AND IMPLEMENTATION OF A PID-BASED LUMINANCE CONTROL AND LIGHT SENSING USING SMOOTHING AVERAGING TECHNIQUE

2016 ◽  
Vol 78 (6-3) ◽  
Author(s):  
Editha Macorol ◽  
Favis Joseph Balinado ◽  
Leo M. Flores ◽  
Ezekiel V. Pascual ◽  
Christian M. Silva ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Luminance Level ◽  
Light Sources ◽  
Averaging Technique ◽  
Light Emitting ◽  
Incandescent Light ◽  
Light Sensing ◽  
Light Stimuli ◽  
Compact Fluorescent Lamp ◽  
Global Energy Consumption

Nowadays, lighting shares a large part in the global energy consumption, lighting consumption can be easily reduced with the use of efficient light sources. The most commonly used light source is the incandescent light bulb. As time passed by, Compact Fluorescent Lamp and Light Emitting Diode use became prevalent because of their advantages over the incandescent light. The researchers were able to develop and implement a PID controlled lighting system using Light Emitting Diode utilizing the smoothing-averaging technique in its sensors. Tests were done with the system with and without smoothing technique to identify the effect of the technique used. The system automatically varies its light intensity output depending on the light stimuli maintaining the luminance level of the laboratory based on standards.

Light Emitting Diode Technology: Lowering Build and Maintenance Costs

2013 ◽  
Author(s):  
Roger Buelow ◽  
Keith Kazenki ◽  
Greg Flies
Keyword(s):  
Energy Efficient ◽  
Light Emitting Diode ◽  
Efficient Technology ◽  
Maintenance Costs ◽  
Light Emitting ◽  
Fluorescent Lamps ◽  
Feasible Option ◽  
Energy Efficient Technology

Due to the recent push for energy efficient technology, LEDs have developed to be able to meet and surpass fluorescent lamps in terms of efficiency and lifetime. Additional focus on LEDs has allowed the initial investment price to decrease allowing LEDs to become a feasible option. Installing LEDs during the construction of ships allows for a greater TOC savings from increased energy efficacy, lower maintenance costs and a simpler electrical design schematic. There are three options available to incorporate LEDs on a ship: LED lamps, LED fixtures or a combination of the two.

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