REDUCING LIGHTING ENERGY CONSUMPTION AT MPCL

Lighting has tremendous potential of saving. Plant lighting is also a major part of auxiliary consumption of power plant. Efficient lighting system can reduce the Power plant auxiliary consumption to the considerable level. Considering Go Green policy and to improve plant efficiency, I like to suggest minor modification in the plant lighting system which could suppress the auxiliary consumption and improve the sustainability.The Power blocks or the turbine Buildings and Electrical Buildings of MPCL are well closed from all the sides making the area dark and opaque in day timing as well. This leads to 24hrs lighting requirement which is impacting plant auxiliary consumption of MPCL. As QATAR have abundant hours of sunshine over the year (minimum of 8.33 hrs per day to maximum of 13 hrs. per day over the year) **, thinking of utilizing day lighting or sunshine to illuminate the dark areas of the plant where it is feasible.AIM : Turn off Electric lighting during Daytime with the Daylighting conceptDaylighting is the practice of placing windows or other openings and reflective surfaces so that during the day natural light provides effective internal lighting.Average monthly hours of sunshine over the year can be seen in the below graph.

Using daylight in your building is a key strategy for passive design. Letting sun into your building impacts Visual comfort. Effective internal lighting can be provided to each power block by fitting skylights on turbine or electrical building roof and glass windows, clerestory windows on side walls by using the concept of passive daylighting or active daylightingThe concept of Passive daylightingis a system of both collectingsunlightusing static, non-moving, and non-tracking systems (such aswindows,sliding glass doors, mostskylights,light tubes) and reflecting the collecteddaylightdeeper inside with elements such aslight shelves. Passive daylighting systems are different from Active daylighting.Active daylighting is a system of collecting sunlight using a mechanical device to increase the efficiency of light collection for a given lighting purpose. Active daylighting systems having active systems that track and/or follow the sun, and rely on mechanical mechanisms to do so.Like most things, daylighting has advantages and disadvantages. But by becoming skilled at understanding the technical components of daylighting, you can make sure to maximize the advantages and minimize disadvantages.

Passive daylightingActive daylighting

Fixed placementRotating mirrors

No supplemental helpSolar powered GPS control

Heat gainDual diffuser heat trap

Glare and Hot spotsEvenly distributed light

Midday efficiencyCaptures low sun angles

Minimal impactMaximum effectiveness

Measures Used in Daylighting DesignBased on these measures, lighting designers use some additional metrics like daylight factor and daylight autonomy to help them optimize and communicate the quantity and quality of daylight within a space. This is important because the availability of daylight can change a lot throughout the day based on sky conditions. Daylight FactorThe actual illuminance levels in a space from daylighting can vary greatly a due to the cloud cover and position of the sun. To deal with these highly variable sky conditions, some building codes and design briefs use daylight factors as the design criteria instead of illuminance on the working plane.Daylight factors are expressed as the percentage of natural light falling on a work surface compared to that which would have fallen on a completely unobstructed horizontal surface under same sky conditions. The daylight factor is analyzed at a point, but these values are often averaged across an entire room or visualized on a grid.A daylight factor of 5% on an internal surface means that it received 1/20th of the maximum available natural light.Daylight Autonomy (DA) and Useful Daylight Illuminances (UDI)Daylight Autonomy (DA)is the percentage of working hours when lighting needs are met by daylight alone. It is measured by comparing daylight illuminance on a workplane to the minimum requirement over time. This is a very popular metric and can tell you how often lights need to be on to meet specific illumination requirements.Useful Daylight Illuminances(UDI) also measures a percentage of time that a space receives adequate daylight, but it also quantifies when the light levels are too high and too low. UDI is based on three standard bins (which broadly line-up with comfortable illumination levels cited above). Less than 100lux is insufficient daylight Between 100 lux and 2000 lux is useful daylight More than 2000 lux is too much daylight and can result in visual and thermal discomfort

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