1. Panida Boonyaritdachochai
Simplified Conducting an Energy Usage Study for a Commercial Home Office
Panida Boonyaritdachochai
The 11th Annual PQSynergy International Conference
Le Meridien, Chiang Mai
19-21 September 2011
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2. Outline Assumption Light Sensor Technology Monitoring Result
Cost Assessment
Conclusions
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3. Assumption
Location: Power Quality (Thailand) Co., Ltd, Ramkamhaeng Rd. Soi 90, Bangkok, Thailand.
Power Supply: Metropolitan Electricity Authority (MEA)
Lamp Technology: 2 Fluorescent Lamps
Two cases in this study.
Operation Time of Light Sensor
Turn On Lamp: 18.00
Turn Off Lamp: 06.00
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4. Light Sensor Technology
A light dependent resistor (LDR) or photoresistor is a resistor whose resistance decreases with increasing incident light intensity.
A photoresistor is made of a high resistance semiconductor. If light falling on the device is of high enough frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band.
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5. Light Sensor Technology
The resulting free electron (and its hole partner) conduct electricity, thereby lowering resistance.
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6. Energy Meter This case study uses “Energy Platform 1” from Dranetz.
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7. Energy Feature Setting
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8. Capable to Power Quality Measurement
RMS variation
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9. Capable to Power Quality Measurement
Waveform Samples
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10. Capable to Power Quality Measurement
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11. Energy Meter Installation
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12. Measureing Energy Consumption
Avg value is used to calculate
the electricity cost.
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13. Electricity Cost
From the MEA monthly bill, our revenue meter read as 635 kWh with billing 2, Baht. So, the average cost is 3.8 Baht/kWh.
As an hour measuring of energy consumption has average by kWh, so the energy consumption cost is approximately
(3.8*0.152) ≈ 0.5 Baht.
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14. Electricity Cost Reduction
Case I: 2 FL lamps without light sensor
24 hours are assumed for turn on the lamps.
The monthly bill will be (0.5*24*30) = 360 Baht.
Case II: 2 FL lamps with light sensor
The lamps are turned on for 12 hours (6 pm – 6 am).
The monthly bill will be (0.5*12*30) = 180 Baht.
The cost reduction is 180 Baht/month.
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15. Cost Assessment Light sensor cost is about 300 Baht. Fluorescent Lamps
The 3 years warrantee
Specification 1500 W
Reference: (
Fluorescent Lamps
The cost of FL lamps is not considered due to it is the same for both cases study.
The life cycle is 12,00o hours ≈ 1.3 year. This is advantageous for extended life.
Installation Labor is 300 Baht referred by an electrical worker.
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16. Cost Effective Solution
Total investment cost of light sensor is
( ) = 600 Baht.
Labor
Light Sensor
The electricity reduction cost is 180 baht/month
The payback period can be calculated from
(180 x 3) = 540 Baht
(180 x 4) = 720 Baht
Saved our money for a year as (180 x 8) =
!!!!! 1,440 Baht !!!!!
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17. Conclusion
The light sensor type LDR is “Energy Saving Technology” for security, outdoor or landscape lighting system.
As a simplified case study, it is less than 5 months for payback period.
A study of energy saving is influenced by many factors i.e.
type of lamp or sensor technology
electrical design
life cycle of technology
electricity tariff
Labor cost
etc
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18. Thank You
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