Techno-economic and environmental viability of retrofitting in public multi storey buildings

This study investigated the pattern of energy consumption of an existing multi-storey building, namely, the Senate building, University of Lagos. In this case study, the electrical facilities of the Senate building of University of Lagos were audited with the aim of improving the energy efficiency of these facilities. The aim of this study was to assess the pattern of energy consumption and at the same time investigate the cost effectiveness and environmental-benefit analysis of retrofitting, in a multi-storey building.

International Journal of Mechanical Engineering and Technology (IJMET) Volume 10, Issue 12, December 2019, pp 527-540, Article ID: IJMET_10_12_050 Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=12 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication TECHNO-ECONOMIC AND ENVIRONMENTAL VIABILITY OF RETROFITTING IN PUBLIC MULTI-STOREY BUILDINGS Gbadega Peter A Department of Electrical Electronic and Computer Engineering, University of KwaZulu-Natal, King George V Avenue, Durban, 4041, South Africa Inambao Freddie L Department of Mechanical Engineering, University of KwaZulu-Natal, King George V Avenue, Durban, 4041, South Africa https://orcid.org/0000-0001-9922-5434 perosman4real1987@yahoo.com, Inambaof@ukzn.ac.za ABSTRACT Multi-storey buildings are becoming a common feature in several campuses and major cities in Nigeria This study investigated the pattern of energy consumption of an existing multi-storey building, namely, the Senate building, University of Lagos In this case study, the electrical facilities of the Senate building of University of Lagos were audited with the aim of improving the energy efficiency of these facilities The aim of this study was to assess the pattern of energy consumption and at the same time investigate the cost effectiveness and environmental-benefit analysis of retrofitting, in a multi-storey building The cost effectiveness of different lighting technology alternatives were considered The present lighting technology and four other energy efficient lighting technology alternatives were compared based on their electricity use CO2 emissions associated with the Senate building of the University’s electricity use would be reduced by about 10 %, if the technology alternatives that saved the most electricity were installed From the economic analysis point of view, T8-E and CFL were seen to be cost-effective due their low lamp cost price and life cycle cost compared to other lighting technology alternatives This project recommends the adoption of standards, energy efficiency and conservation measures to ensure building sustainability within Universities Keywords: Energy consumption, cost effectiveness, energy efficiency, economic analysis, conservation measures, lighting technology Cite this Article: Gbadega Peter A and Inambao Freddie L, Techno-Economic and Environmental Viability of Retrofitting in Public Multi-Storey Buildings International Journal of Mechanical Engineering and Technology 10(12), 2020, pp 527-540 http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=12 http://www.iaeme.com/IJMET/index.asp 527 editor@iaeme.com Gbadega Peter A and Inambao Freddie L INTRODUCTION The most important aspect of the world is energy Its functions include powering various types of vehicles, heating and cooling of homes and lighting of the cities as well as many other applications Everything done by people is linked to energy source in one way or another [1, 2] Since the industrial revolution in the 18th and19th centuries the main source of energy has been fossil fuels The success of many inventions are as a result of the substantial contribution of the various types of fossil fuels This is mainly due to relatively high-energy content and flexibility in how they can be used Regrettably, fossil fuels are non-renewable and, more significantly, owing to their emission of harmful gases to the atmosphere, they cause pollution [3, 4] To reduce the effect of these gases, researchers are seeking to determine the effectiveness of alternative energy sources to meet energy demands Thus, renewable energy sources are being considered, harnessed and transformed into usable forms of energy Another way to reduce these emissions is to efficiently and effectively make use of the available energy in order to reduce the environmental effect of energy wastage Consequently, it is advised that techniques for energy efficiency improvement be devised and subsequently applied to multi-storey buildings This can significantly reduce their energy demands as well as their carbon footprint [5, 6] Furthermore, improving the energy efficiency of homes, businesses, schools, governments, and industries is one of the most constructive, cost-effective ways to address the challenges of high energy prices, energy security and independence, air pollution, and global climate change [7] The most damaging environmental consequence of fossil fuel combustion is the production of CO2, a gas which affects global heat balance, and contributes to global warming [8, 9] In addition to environmental consequences, the rise in energy use is expensive because more plants need to be built to serve the loads [10, 11] For many years, it has been suggested that a cost effective means to reduce the amount of energy used by the human population would be the adoption of energy efficient technologies, particularly within the industrial and commercial sectors [10, 11] Studies indicate that improvements in energy efficiency will reduce local and regional energy related environmental challenges, and that the widespread adoption of energy efficiency measures will result in significant reductions in CO2 emissions globally [1, 4, 8] Energy wastage is rampant in society today, hence, this study investigates how energy can be used efficiently to reduce wastage and greenhouse gas emissions Many studies have been carried out on the economic viability of Energy Efficient Measures (EEM) in developed countries In developing countries such as Nigeria, indiscriminate energy-use still exists even in new buildings This is due to the ignorance of consumers and energy providers on the advantages of EEM Therefore, this study evaluates the cost effectiveness and environmental benefits of applying EEM in an academic environment [12, 13] The aim of this study is to assess the pattern of energy consumption and at the same time investigate the cost effectiveness and environmental-benefit analysis of retrofitting, in a multi-storey building This paper is organized in the following way: section is an overview of the mitigation devices for minimizing energy consumption patterns Section describes the results and analyses of various energy management schemes and the economic analysis of various technologies for cost effective energy consumption Section concludes the study MITIGATION DEVICES FOR MINIMIZED ENERGY CONSUMPTION PATTERNS The goal of energy efficiency, energy management and energy conservation is to reduce the consumption of energy This is usually accomplished by means of data analysis of an energy audit Evaluation of energy saving measures is done by creating a list of cost-effective energy http://www.iaeme.com/IJMET/index.asp 528 editor@iaeme.com Techno-Economic and Environmental Viability of Retrofitting in Public Multi-Storey Buildings conservation measures and determined by using both economic analysis and energy savings analysis [12, 14] Firstly, a predefined list of energy efficiency and conversation schemes is prepared, after which the energy savings due to the various energy conservation measures related to the building are estimated [5] The installation or initial costs needed to employ the energy conservation measures are evaluated and the cost effectiveness of individual energy conservation measure are explicitly assessed Steps are then taken to minimize energy consumption such as lighting improvements, which involves retrofitting of lamps and utilizing of lighting control systems Following an initial review of similar projects paying attention to the challenges faced, execution was logically broken down to the following: energy audit, demand side management, energy efficiency, cost-effectiveness and environmental impact (benefits) analysis of energy efficiency measures (schemes), energy conservation [10, 13] 2.1 Methods Adopted to Carry out the Research For the purpose of fair presentation and clear understanding of this exercise, this subsection is concerned with the method of collecting, classifying and processing information gathered from a field survey To evaluate the energy consumption pattern in a multi-storey building, a case study of the University of Lagos Senate house is presented A walkthrough audit was implemented to [19, 20]:  Take note of the kind of lighting being used by the consumers  Observe the kind of air cooling systems used in the building  Acquire the power ratings of each equipment (theoretical values) and measure the actual amount of power they consume (experimental value) Evaluation of the amount of power consumed by the electrical motors (lifts) on a daily basis in the building was carried out The energy consumption of lifts typically represents 3% to 8% of the total energy consumption of buildings, depending on the structure and usage of the building, the type and the number of lifts [9-11] 2.2.1 Categorization of Rooms Table Room categories and the 20 room types identified in the energy survey Room categories Group Group Group Group Room types Office Portal’s unit Senate house maintenance annex Council affairs unit Information unit Maintenance unit Electronic data processing unit Legal unit CITS (annex) Reconciliation unit Student’s records annex Enquiry unit Ground floor fittings Building basement Expenditure control Staircase and lobby http://www.iaeme.com/IJMET/index.asp 529 editor@iaeme.com Gbadega Peter A and Inambao Freddie L Group Senate chamber UNILAG radio Conference room Security unit A survey of every room in the Senate building of University of Lagos was carried out to know the number of 1.2 m fluorescent fixtures, incandescent lamps, LED lamps, cooling technology, heating equipment etc During the course of the survey, information about the hours of operation of these electrical appliances were gathered The rooms were divided into categories, containing 20 types of room, which were identified within the study buildings as shown on Table Therefore, based on the operating hours per day, room categories to were defined 2.2.2 Estimation of Electricity Consumption and Cost Energy consumption of the light fittings is the product of the number of retrofits, power consumption and operating hours of a lamp The annual energy consumption or the amount of energy consumed yearly by existing lighting technology was computed mainly for individual room categories The estimates are expressed as follows: ( ) (1) Where = The number of fixtures = The power used per fixture in watts = The number of operating hours per year [10] The results for different fixtures were cumulated to estimate a total kWh/yr value for each room category The cost of the electricity used by existing fixtures was also calculated for each of the five room categories within the buildings using Eq (2) Electricity cost was calculated by estimating the percentage of operating hours, demand charge and annual fixed charge An example of the calculation is shown below for a particular room category: ( ) *( )+ (2) Where = The annual fixed charge = The number of operating hours per year = The electricity charge At the case study location, the peak charge is N13.61 /KWh The total electricity costs are multiplied by N1.3210 to account for the demand charge The electricity consumption and cost was calculated for four energy efficient lighting technology alternatives These four technology alternatives were chosen due to the fact that they are easy to install, and have the potential to save significant amounts of energy For each of the four alternatives, Eq (1) was adopted to calculate the amount of electricity consumed yearly in each category Eq (2) was utilized to calculate the annual cost of the electricity utilized by individual lighting technology alternatives in each room category http://www.iaeme.com/IJMET/index.asp 530 editor@iaeme.com Techno-Economic and Environmental Viability of Retrofitting in Public Multi-Storey Buildings Table The four lighting technology alternatives assessed in this study [2] Light technology Lamp Lamp life Advantages ratings span (Watt) (Hours) Electronic ballast 18 7500 Rugged due to its hard structure CFL 10000 Environmentally friendly T8 Electronic 32 8000 cheaper T5 21 8000 It’s more robust Table shows the four lighting technology alternatives illustrating the lamp ratings, lamp life span and the advantages of adopting each of the technologies in the study 2.2.3 Economic Analysis Based on the walk-through audit (energy survey) that was carried out, an economic analysis of the energy consumption pattern was estimated The results obtained were used to estimate the cost effectiveness of installing various lighting technology alternatives In order to actualize this, the installation cost and 20-year cash flows were calculated for individual technology alternatives in each room category The disposal costs, material (including ongoing maintenance costs) and electricity costs were also considered The 20-year time span denotes the life cycle of 1.2 m and m fluorescent lighting systems, which are the longest lived components (ballasts) This study utilized three economic analyses techniques in order to determine the cost effectiveness of various lighting technology alternatives, namely: cost of conserved energy (CCE), net present value (NPV), and simple payback time (SPT) [2, 10] 2.2.3.1 Simple Payback Time The SPT measures the amount of time required to recuperate the additional investment on efficiency improvement through lower operating costs SPT is the time it takes for an initial investment to be recouped and is found by using the following equations: (3) (4) Although the SPT technique is insufficient for ranking investments based on their anticipated profitability [19], this technique was adopted due to the fact that it is still globally utilized as a benchmark for accepting or rejecting potential investments [10, 18] 2.2.3.2 Net Present Value The NPV technique estimates the present value of an investment n years into the future NPV is known as a sound technique for jointly assessing a number of investment opportunities with different initial investment amounts and differing cash flow patterns [21] Eq (5) was used to calculate the NPV: ∑ ( (5) ) Where = The annual cash flow in year t = The discount rate http://www.iaeme.com/IJMET/index.asp 531 editor@iaeme.com Gbadega Peter A and Inambao Freddie L = The investment time in years = The initial investment amount The discount rate adopted in the NPV evaluations was calculated to be % This value was selected due to the fact that it is within the rate of returns usually expected by commercial and industrial organizations for an investment in energy efficient lighting technology [12, 16] NPV can be mathematically expressed as: ( ( ) ( ) ( ) (6) ) ( (7) ) Where = % (discount rate) = The number of years 2.2.3.3 Cost of Conserved Energy The CCE analysis technique estimates the cost of conserving one-kilo-watt-hour (kWh) of electricity If the installation of energy efficient technology results in a CCE, which is less than the price paid for one kWh of electricity, the project may be considered cost effective CCE is described in more detail in [19, 20] Eq was used to determine the CCE that related to a particular investment: ( (8) Where the change in annual maintenance cost can be either positive or negative and annual energy saving is expressed in kWh CRR is the capital recovery rate, and is used to annualize the investment CRR is expressed as: ( (9) ) Where d is the discount rate and n is the length of the investment in years 2.2.3.4 Life Cycle Cost The evaluation of the cost of a system or product over its entire life span is known as life cycle cost (LCC) Life cycle cost analysis is a method of determining the entire cost of a structure, product, or component over its expected useful life The cost of operating, maintaining, and using the item is added to the purchase price In this study, LCC was utilized to estimate the cost of energy efficiency enhancement of the lighting system based on design options The LCC is the sum of investment cost (PC) and the annual operating cost (OC) discounted over the lifetime of the product The LCC is evaluated using Eq (10) [17, 20]: (10) 2.2.3.5 Energy Savings Energy saving (ES) is the difference between energy consumption of existing (EC existing) and retrofit lighting (EC retrofitting) a system The following equation was used to calculate energy savings [14, 15] (11) http://www.iaeme.com/IJMET/index.asp 532 editor@iaeme.com Techno-Economic and Environmental Viability of Retrofitting in Public Multi-Storey Buildings 2.2.3.6 Electricity Consumption and CO2 Emissions Carbon dioxide emissions related to the electricity consumed by existing 1.2 m and m fluorescent lighting fixtures were estimated for the whole Senate building of University of Lagos For these calculations, it is assumed that the generation of kWh of electricity produces 1.3 kg of carbon dioxide [18, 19] RESULTS AND DISCUSSION The site for this study was the Senate building of University of Lagos This building was chosen as the study site because the building serves as the heart of the institution where various activities take place, hence the need for constant supply of electricity More so, most of the lighting technology installed in the building is high energy consuming (1.2 m fluorescent lamps, incandescent lamps and a few LED lights) Generally, AC consumes a lot of energy compared to modern technology As a result, there is a dire need to make the building energy efficient by installing new energy efficient technology (alternative technology for lighting and cooling) The total energy consumption by all the facilities in the Senate building of University of Lagos are illustrated by the pie chart in Figure From Figure it is clear that the facilities that consume the bulk of the energy are cooling (36.4%) and lighting (26.4%) The energy survey assessed that the lighting system had the greatest potential to save electricity and reduce electricity related CO2 emissions and was assessed by comparing four energy efficient lighting technology alternatives The cost effectiveness of each lighting technology alternative was estimated Figure Pie chart illustrating the energy utilized by all the building facilities The results of the lighting survey for the room categories are presented in Figure In general, most lighting fixtures are found in room categories and 3, although room categories and contain most of the single lighting fixtures http://www.iaeme.com/IJMET/index.asp 533 editor@iaeme.com Gbadega Peter A and Inambao Freddie L Figure Annual Energy consumption by the lighting technologies From Figure CFL consumed the least energy compared to the other lighting technology alternatives E-ballast also consumed less energy compared to the existing lighting technology As a result, CFL and E-ballast are energy efficient lighting technologies which when installed would make the building more energy efficient 3.1 Electricity Consumption and Cost Figure shows the electricity consumption by the 1.2 me and m fluorescent lights in each room category for each lighting technology alternative In all cases, room categories (offices) and (Annex and units) consume the most electricity, even though rooms in category contained the second largest number of globes This is due to shorter operating hours within room category 3, and indicates that operating hours is an important factor in the electricity consumption of 1.2 m and m lighting fixtures Furthermore, it is obvious that the CFL lighting technology alternative is by far the most energy efficient alternative Undiscounted life cycle costs for various lighting technology alternatives are shown in Figure The costs are divided into electrical costs, initial costs and ongoing maintenance costs It can be seen that although ongoing maintenance costs change to some degree, initial costs change noticeably between the lighting technology alternatives It is worth noting that T8-E Electronic is the only technology alternative with low initial costs Therefore, annual cost saving and annual electricity costs are shown for each lighting technology alternatives Electricity savings are calculated in kWh so that results can be easily compared with respect to other studies Table The electricity cost/use per year of various lighting technology alternatives Lighting technologies Electricity cost/year (N) Electricity used (kWh/yr) Electricity saved (kWh) EXISTIN CFL G Million Million (Naira) (Naira) T5 E-BALLAST T8 – ELECTR Million Million ONIC (Naira) (Naira) Million 0.862 0.395 0.826 0.554 0.944 0.197 0.0089 0.188 0.126 0.216 N/A 0.108 0.0082 0.0712 -0.019 http://www.iaeme.com/IJMET/index.asp 534 editor@iaeme.com Techno-Economic and Environmental Viability of Retrofitting in Public Multi-Storey Buildings From Table it is evident that CFL has the least electricity cost/year, followed by Eballast; this shows that CFL serves as the best lighting technology alternative when cost of energy-use is being considered Electricity savings of CFL is the highest of all the lighting technology alternatives In view of this, it is expedient to install CFL since it is more economical Figure Life cycle cost for a duration of 20 years Figure Breakdown of LCC components From Figure it is evident that CFL has the least life cycle cost which makes it cheaper in terms of operating costs for a duration of 20 years; this makes it the best lighting technology alternative from an economic point of view http://www.iaeme.com/IJMET/index.asp 535 editor@iaeme.com Gbadega Peter A and Inambao Freddie L Figure Energy savings by the lighting technology alternatives From Figure it can be seen that CFL and E-ballast save the highest amount of energy compared with other lighting technologies, therefore installing these two lighting technologies in a typical building will makes the building more energy efficient 3.2 Economic Analyses The results of the economic analysis are shown in Table and indicates that all of the lighting technology alternatives assessed represent good investment choices if all room categories are considered together, so they are all economically viable Table The estimated net present value of the lighting Net Present Value Existing CFL T5 E-ballast T8-E NPV Million (Naira) 40.12 55.7 48.16 25.53 Installation /Initial Cost (Million) 3.67 5.11 4.42 2.32 http://www.iaeme.com/IJMET/index.asp 536 Replacement Cost (Million) (Naira) 3.67 5.11 4.42 2.32 Maintenance /operating Cost (Million) 0.48 0.48 0.48 0.48 editor@iaeme.com Techno-Economic and Environmental Viability of Retrofitting in Public Multi-Storey Buildings Figure Chart showing the net present value of lighting technologies From Figure it can be seen that T8-E has the least NPV of an investment 20 years into the future due to its low lamp price; in view of this T8-E is the most economically viable Figure Chart showing the simple payback time The SPT measures the amount of time needed to recover the additional investment on efficiency improvement through lower operating costs From the analysis, T8-E has the least payback time, followed by T5, and CFL has the longest payback time If we are to base our cost-effectiveness analysis on the time the investment would pay back, then T8-E would be the best choice to make http://www.iaeme.com/IJMET/index.asp 537 editor@iaeme.com Gbadega Peter A and Inambao Freddie L Figure Chart representation of CCE (C/kWh) The above analysis shows that CFL, E-ballast and T8 are most cost effective, since the cost of conserved energy is less than the price paid for one kWh of electricity, which is N13.61 Figure Chart representation of CO2 emitted per year From the analysis, CFL has the least amount of CO2 emitted per year, which means it is the most environmentally friendly lighting technology Figure shows that more than half of the CO2 emitted by existing technology can be avoided by the use of CFL http://www.iaeme.com/IJMET/index.asp 538 editor@iaeme.com Techno-Economic and Environmental Viability of Retrofitting in Public Multi-Storey Buildings Figure 10 Energy savings for cooling system The cooling technology alternatives proposed are Panasonic (IS 85.3 W) and LG series (188.2 W) Both technology alternatives are energy efficient based on the fact that they save more energy which invariably reduces the energy operating cost From Figure 10 it is evident that LG series and Panasonic (IS) save more energy compared to the existing cooling system CONCLUSION This work is a detailed analysis of the mitigation techniques of minimizing energy consumption patterns To start with, various energy management measures were investigated critically to gain an overview and better understand the scope of energy management schemes After this, various economic analyses were carried out to investigate the cost effectiveness of the various technologies proposed From the results obtained, CFL and T8-E are the best lighting technologies in terms of energy efficiency and cost effectiveness measures This project recommends the adoption of standards, energy efficiency and conservation measures to ensure building sustainability within Universities REFERENCES [1] Sunny, O O A Quantified Assessment of Energy Demand in a Developing Nation in the Year 2022–A Nigerian Perspective International Journal ff Scientific & Technology Research, 3, 2014, p 196-200 [2] Oluseyi, P O Babatunde, and Babatunde, O Assessment of Energy Consumption and Carbon Footprint from the Hotel Sector within Lagos, Nigeria Energy and Buildings, 118, 2016, pp 106-113 https://doi.org/10.1016/j.enbuild.2016.02.046 [3] Donovan, D M Ecotrain Green Career Guide Almanac: 2010 2011 Volume 2, Portland, OR: Ecotrain Media Group, 2010 [4] Emenike, D A Qualitative Case Study of Nigeria Electric Power Outage and its Economic Consequence Dissertation, Phoenix: University 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Techno-Economic and Environmental Viability of Retrofitting in Public Multi- Storey Buildings From Table it is evident that CFL... by individual lighting technology alternatives in each room category http://www.iaeme.com/IJMET/index.asp 530 editor@iaeme.com Techno-Economic and Environmental Viability of Retrofitting in Public