Energy Saving at Kathmandu University. A Project Design to Lower Energy Consumption and Costs in the Girls' Hostel, Block-17

Table of Contents

EXECUTIVE SUMMARY

LIST OF FIGURES

LIST OF TABLES

1. INTRODUCTION
1.1 Background
1.2 Objective
1.3 Scope of Assessment

2. ENERGY CONSUMPTION

3. EXPECTED SAVING AND ECONOMIC ANALYSIS
3.1 Expected Saving When Replaced by LED light
3.2 Economic Analysis with Solar Implementation

4. RISK ASSESSMENT
4.1 Financial Risks
4.2 Environmental Risks

5. ENERGY SAVING STRATEGY MODELLING
5.1 CFLs and FTLs are replaced by LED light
5.2 Solar-Grid Hybrid System

6. CONCLUSION

REFERENCES

ANNEX 1: Illuminance Level

ANNEX 2: Room wise Individual consumption of CFLs and FTLs

ANNEX 3: Room wise Individual consumption of LED (when replaced)

ANNEX 4: Quotation for Solar System and LED Bulb

ANNEX 5: Calculation for Comparison OF LED and CFL Energy Cost

ANNEX 6: PVSYST Output

EXECUTIVE SUMMARY

This project report draws attention to the energy management process and opportunities in girls’ hostel (Block-17) of Kathmandu University and different energy saving strategy with economic analysis and risks involved.

The major energy consumption in building is the lighting sources and consumes 73kWh/day in average with maximum loading of 8.652 kW. The major lighting sources, which consumes electricity, are Fluorescent Tube Lights (FTLs) and Compact Tube Lights (CFLs) used in building lighting design. The calculated cost of electrical energy by these sources are NRs.22746.30 under certain assumptions.

The expected saving opportunities in building are by meeting state-of-the-art in lighting technology achieved by replacement of CFLs and FTLs by LED technology and Boost the building by green energy. The first opportunity save electricity 39kWh/day in average and thus reduction in cost by 53.3%. The second one option goes to green energy but have higher cost of energy. The both saving opportunities have its own financial and environmental risks involved.

The two model is developed in above discussed opportunities; i) Replacement of CFLS and FTLs by LED in stages and ii) Solar-Grid Hybrid System. The each developed model save energy and also its cost and both have low environmental and financial risks involved in it.

In conclusion of this report, the synergism of both model makes one more appealing than the oters for implementation decision in girls’ hostel which not only save the energy but also the cost of energy with reduction of maximum demand of energy

LIST OF FIGURES

Figure 1: Monthly Electricity Bill of Girls' Hostel

Figure 2: Comparison of energy Consumption, Demand and Cost of Energy of CFL and LED

Figure 3: Comparison of Life Cycle Cost of FTL and LED light for 6 years of Operation

Figure 4: PVSYST window for costing solar system in existing condition

Figure 5: PVSYST window for costing of solar system for LED based system

Figure 6: Model for replacement of CFLs and FTLs by LED light

Figure 7: Cost of electricity generation for Hybrid system with 4kWp solar PV system

Figure 8: Model for Solar-Grid Hybrid System

LIST OF TABLES

Table 1: CFL and FTL Connected in Buildings

Table 2: Replacement Opportunities Options

Table 3: Comparison of Life Cycle Cost of FTL and LED light for 6 years of Operation

1. INTRODUCTION

1.1 Background

Energy use in buildings currently account for about 32% of the global total final energy consumption in the world¹. Electric lighting is a major energy consumer in typical residential buildings. Enormous energy savings are possible using energy efficient equipment, effective controls, and careful design. The residential buildings in the urban centers of Nepal mainly use electricity and LPG for lighting, heating and cooling purposes².

Electric lighting design also strongly affects visual performance and visual comfort by aiming to maintain adequate and appropriate illumination while controlling reflection and glare. Lighting is not just a high priority when considering residential building design; it is also a high- return, low-risk investment. By installing new lighting technologies to meet the state-of-the-art, one can reduce the amount of electricity consumed and energy costs associated with lighting.

This project mainly concentrates on the energy saving potentials in lighting of Girls’ Hostel Block (Block -17), covers total area of 2604.00 sq. meter, of Kathmandu University located at Dhulikhel³.

1.2 Objective

The objective of this Preliminary Energy Audit is primarily to assess current lightning scheme and the viability of implementing an energy efficiency upgrade of the facility including a subsequent Investment Grade Audit.

This objective will be achieved by:

- Identifying a suitable energy performance indicator for existing and target energy use to quantify the potential for energy savings.
- Identifying a suite of measures, including savings and implementation budget,
- Identify any potential technical, financial risks to the project as currently defined.

1.3 Scope of Assessment

The assessment includes the electrical energy consumption in lighting the building with possible saving opportunities by replacement of energy efficient lighting technologies and uses of renewable energy sources and the financial assessment.

The assessment has certain assumptions which are:

- The operating hour of each lighting sources are same for all days.
- There is no any seasonal load variation.
- The survey data is same for all days.
- The cost of energy (kWh) is taken to be NRs. 9.3/kWh, which is weighted average cost of energy for non-commercial tariff rate, and demand charge is NRs. 220/KVA.
- It is not considered that energy saving can be obtained by changing lighting design scheme. i.e. the scheme of lighting design is perfect.
- The light energy (lux) reaching at the table or place, used for study, is in range and the lower values are due to the ageing of luminaire. The lux measured are in ANNEX 1.

2. ENERGY CONSUMPTION

The building has total 112 rooms; 11 in ground floor, 28 in each 1st floor, 2nd floor and 3rd floor and 17 in top floor. The total CFLs and FTLs connected in building are shown in table 1 and individual details are is ANNEX 2.

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Table 1: CFL and FTL Connected in Buildings

The total capacity and energy consumption of lighting load are 8652W and 73kWh/day respectively. The per month energy consumption cost for the above load is calculated, assuming power factor 0.8, as

= 73 kWh/day * NRs. 9.3/kWh * 30 + (8.652/0.8) KVA*NRs. 220/KVA = NRs. 22746.30 per month.

The annual bill of electricity of building of F/Y 2070/71 shown below:

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Figure 1: Monthly Electricity Bill of Girls' Hostel

The major source of energy consumption in building is the lighting source and the average energy cost for FY 2070/71 is NRs. 21628.50 per month. This figure is nearly same as the calculated value, therefore, the assumptions made are précised to the correct value.

3. EXPECTED SAVING AND ECONOMIC ANALYSIS

3.1 Expected Saving When Replaced by LED light.

The lighting design scheme is not considered to be changed and there is adequate light at day time which uses natural lighting. The expected saving can be brought by replacing the luminaire with high efficient and lower energy consumption. For this purpose, the CFLs and FTLs are replaced by LED light.

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Table 2: Replacement Opportunities Options

When the CFLs and FTLs are replaced by LED lights then the load and energy consumption are 4268W and 34.3 kWh/day. LED lights have greater power factor than the FTLs and is to be minimum 0.9. Thus the total energy cost per month is:

= 34.3 kWh/day * NRs. 9.3/kWh * 30 + (4.268/0.9) KVA*NRs. 220/KVA = NRs. 10613 per month.

The cost saving is NRs 12133.3 per month. The comparative savings in energy, demand and cost are shown in figure 2.

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Figure 2: Comparison of energy Consumption, Demand and Cost of Energy of CFL and LED

The detailed calculations for the replacement of LED light is in ANNEX 3. From the figure 3, it is seen that the cost saving after LED light replacement is 53.3%.

The average life of FTLs and CFLs are 8000-15000 hours and LED light have life 25000-50000 hours^{4 5}. This also benefits the use of LED light.

The life cycle cost (LCC) of FTL and LED is compared with assumptions that the operating hour of light is 11 hours in a day and the average life of FTL and LED are 8000 hours and 25000 hours respectively. The energy consumption by a single FTL and LED of 40W and 12W are 0.44 kWh/day and 0.132 kWh/day. Energy bill is paid monthly. The discount rate is assumed to be 10%. When using these both for specified time as above, the life of FTL is finished in 2 years and LED light life is finished in 6 years and 3 months. Thus, the comparison is made for 6 years and the capital rates are taken from the quotation ANNEX 4.

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Time Capital Present Cost Capital Present Cost

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Table 3: Comparison of Life Cycle Cost of FTL and LED light for 6 years of Operation

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Figure 3: Comparison of Life Cycle Cost of FTL and LED light for 6 years of Operation

The detail calculation of costs involved in life cycle cost is given in ANNEX 5.

3.2 Economic Analysis with Solar Implementation

The stand-alone solar system is analyzed by software PVSYST and the cost of energy can be $ .31/kWh and the gross investment of $ 47892 for PV array size of 22.46 kWp. This is not viable cost economically and financially to implement this huge amount of solar system.

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Figure 4: PVSYST window for costing solar system in existing condition

The stand-alone system for LED light based system is also analyzed and found to be energy cost of US $ 0.33/kWh and gross investment cost of $ 24633 for PV array size of 11.3 kWp.

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Figure 5: PVSYST window for costing of solar system for LED based system

The cost of investment for both options are very large in comparison to the energy bill of grid electricity. Also the cost of energy is also greater than the grid.

From these figures value, the implementation of solar system is not financially acceptable. But in Nepal, Due to load shedding, diesel is used to provide the reliable supply at huge cost of electricity, in average NRs.40/kWh. If this rate is considered for load shedding time, the solar system may be financially acceptable. The solar system is environmentally friendly and non-polluting source for power production, therefore, can be implemented in replacement of diesel generator set.

The quotation for 1kWp system is given in ANNEX 4. The PVSYST output of solar system in existing system and LED based system are given in ANNEX 6.

4. RISK ASSESSMENT

The implementation of project has certain financial and environmental risks which are discussed below.

4.1 Financial Risks

Financial risks are mainly involve with the implementation of solar system. While implementing the solar system for the diesel generator replacement, the financial risks are involved in the project life. The project life is 25 years and load shedding of Nepal could be made nearly zero for that period of time and within two years, load shedding is drastically reduced when Upper-Tamakoshi of capacity 456MW is completed by 2016. Thus, the cost of energy from grid is reliable and cheaper than the solar power system and it creates financial risks in implementation of solar PV system.

4.2 Environmental Risks

Environmental risks involves in both the options; solar PV system implementation and CFL replaced by LED light.

The main waste that will be produced by the project is used lead acid batteries, that require replacing every eight years or so. Solar panels have a guaranteed life of 25 years, therefore, they will not produce waste for a considerable period of time unless they are physically damaged.

Lead acid batteries need to be recycled to avoid pollution from the lead plates and the sulphuric acid that the plates sit in. Recycling involves the recovery of lead to produce new batteries. Local scrap dealers collect lead for (i) crushing then transportation to India for processing, or (ii) local recycling in small quantities by a battery company, however, neither method is environmentally friendly.

Thin-film PV cells contain a number of more toxic materials than those used in traditional silicon photovoltaic cells, including gallium arsenide, copper-indium-gallium-diselenide, and cadmium-telluride. If not handled and disposed of properly, these materials could pose serious environmental or public health threats. Other impact are related to the land use, visual impact, waste management etc.

When CFLs and FTLs are replaced by LED light, the CFLs and FTLs have no any use in any equipment and process or scrap value for a product and thus is disposed and may cause environmental and health hazards.

Each and every atom of mercury is capable bio-chemically to disable an enzyme or other critical protein in our body. Thus, mercury has the potential to produce significant health effects through series of bio chemical reactions in our body. The mercury ions can cause irreversible damages to several organs, when animals and human organisms, are exposed to them. Even worse, they could lead the organism to death. As well as the inhalation of mercury vapors, the ingestion of food containing organo-mercury, especially methyl mercury (CH3Hg+), represents great health risks.

Typically, a CFL contains 1 mg to 5mg of mercury and higher values for FTL. The estimated weight of a typical CFL is 0.04 kg without base, which is expected to contain around 20% of waste (by weight) as mercury-contaminated waste. The typical 1.2- metre fluorescent lamps contain approximately 0.26 kg of glass, 0.02 kg of combined metals and 0.01 kg of phosphor powder⁶.

5. ENERGY SAVING STRATEGY MODELLING

After studying the energy consumption, expected area of saving and its economic analysis along with the risk assessment of the expected area of saving, the energy saving strategy is modelling in two ways:

5.1 CFLs and FTLs are replaced by LED light.

The CFLs and FTLs are not replaced at a single stage of replacement rather it is replaced in many different stages or milestone. These stages follow the following activity as a stage for replacement:

- The ageing effect of light also emits low light energy and these are replaced in one stage.
- When the CFLs or FTLs are burnt out or damaged or not working by any means and this condition is found frequently then it is replaced by LED light of corresponding equivalent. This activity is frequent and is also a stage.
- A periodic replacement plan is made for low grade luminaire with appropriate and equivalent LED light.

This stage plan is shown diagrammatically in figure and there is a tie interval between two stages.

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Figure 6: Model for replacement of CFLs and FTLs by LED light

This model also reduces high initial investment cost for replacement by LED light and also lower present worth because the investment is divided in certain time interval by creation of the stages in the model.

5.2 Solar-Grid Hybrid System

Nepal suffers an energy crises from several years and increasing demand of electricity increase the demand of diesel generator and whose energy cost of production is about NRs. 40/kWh. Also carbon trading and promotion for the use of renewable energy sources leads to solar PV system. The availability of sun light made solar PV system more feasible for wide range of geographic area. The stand-alone system has high cost of electricity generation and hence the hybrid system should be implemented.

For instance of that building, the 40% of power is provided by solar PV system and hence 4kWp solar PV system should be preferred. The cost of electric energy for this system is $0.18/kWh which is lower value than the stand-alone. The cost of electricity is calculated using PVSYST is shown in figure 7.

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Figure 7: Cost of electricity generation for Hybrid system with 4kWp solar PV system

The PVSYST calculation sheet is in ANNEX 6. The model for this system is shown in figure 8 below.

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Figure 8: Model for Solar-Grid Hybrid System

6. CONCLUSION

The preliminary energy audit for girls’ hostel (Block-17) shows different energy management process such as solar implementation for existing system and LED based system, LED based plan by replacing CFLs and FTLs. These energy management plans have its own environmental and financial risks and thus two different models are planned for energy management process.

The best plan from the two models either individually or in synergism go further for detail energy audit study based on advantages and dis-advantages that, under difference circumstances and from different perspectives. In conclusion of the preliminary energy audit, the synergism makes one more appealing than the others for implementation decision in girls’ hostel which not only save the energy but also the cost of energy with reduction of maximum demand of energy.

REFERENCES

ANNEX 1: Illuminance Level

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*Illuminance level is measured on 27 July, 2015

ANNEX 2: Room wise Individual consumption of CFLs and FTLs

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ANNEX 3: Room wise Individual consumption of LED (when replaced)

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ANNEX 4: Quotation for Solar System and LED Bulb

ANNEX 5: Calculation for Comparison OF LED and CFL Energy Cost

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ANNEX 6: PVSYST Output

1. SOLAR SYSTEM FOR EXISTING SYSTEM

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2. SOLAR SYSTEM FOR LED BASED SYSTEM

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3. SOLAR SYSTEM FOR HYBRID SYSTEM

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¹ IEA, "World Energy Outlook," International Energy Agency, 2010.

² WECS, "National Survey of Energy Consumption and Supply Situation in Nepal," Water and Energy Commision Secretariat, 2010.

³ "Kathmandu University," 06 07 2014. [Online]. Available: http://www.ku.edu.np/university/index.php?go=physical#17. [Accessed 06 07 2015].

⁴ OSRAM COMPANY, "OSRAM DULUX® EL ELECTRONIC ENERGY SAVING LAMPS," OSRAM WI 3/00 Co.

⁵ Philips, [Online]. Available: www.philips.com/masterled. [Accessed 07 08 2015].

⁶ "Guidelines for Environmentally Sound Mercury Management," Central Pollution Ccontrol Board, Ministry of Environment of Forests, Delhi, 2008.