DHVSU Electrical Engineering Department Goes Green: Feasibility of Solar-Powered Building Using an Off-Grid Hybrid Solar Inverter

This research project unfolds the practicability of utilizing an Off-Grid Hybrid Solar Inverter to power up the Electrical Engineering Building in Don Honorio Ventura State University. To satisfy the aims of this research, a Solar PV System design was used to make use of the solar energy converting it to electrical energy to supply the whole building. This study was guided by doing a load schedule of all the appliances in the whole building to acquire the total power and total energy consumption, using it as a basis for the selection of the required electrical components and computation of the roof area to select a suitable solar panel in order to ensure the functionality of the whole Solar PV System. The raw data gathered was analyzed using formulas to acquire the needed electrical values. The findings resulted in the development and completion of the Solar PV System Design. The last part of the research is the results, discussions, conclusions, and recommendations. These provided the finalization and endorsement of the whole study.


Introduction
Energy consumption is becoming a requirement in order to increase income and improve living quality for individuals regardless of where they are or when they are required to do so. Increased population and economic progress, result in a rapidly expanding global energy demand, particularly in major emerging nations, that will account for 90% of energy demand increase by 2035. Simultaneously, approximately 20% of the world's population does not have access to power. The growth of the Philippine economy has always been directly proportional to energy consumption, and thus entails a rising demand for reliable power if the country expects sustained economic expansion post-pandemic (Carlo Lorenciana, 2021). Renewable power can be obtained by generating electrical energy from light, thermal and kinetic energy present within the sensor's environment. These provide the opportunity for alternative types of power sources to traditional batteries (Beeby & Zhu, 2011). The subject of this paper is kinetic energy generators, which convert energy in the form of movement present in the application environment into electrical energy (Beeby et al., 2006) Finding new energy sources to meet the world's expanding demand is one of society's most pressing issues for the next half-century. One of the most essential energy-saving initiatives is the development and utilization of green energy. Solar energy is the most abundant form of energy available to us. It is approximated that 10000 TW worth of solar energy is incident on earth's surface in a day (Bosshard, 2006).
According to a report, the world energy consumption in 2015 was 17.4 TW altogether (Seger, 2016). There has been a minimal increase in energy consumption every year, approximately 1-1.5% annual growth. The world's total energy consumption is expected to grow by 56% by the year 2040 (U.S Energy Information Administration, 2013). Comparing current consumption, projected growth in two decades, and the amount of solar radiation received in an hour we can just imagine the potential solar energy holds. The total energy consumed is not a small fraction of what we receive in an hour. Hybrid energy systems have become more connected, reliable, and intelligent thanks to digital technologies. Striking progress in connectivity and analytics is supporting the development of new digital systems such as smart machines. Digitalization is enhancing the accessibility, safety, and productivity of energy technologies (Asmae Berrada, ... Rachid El Mrabet 2021).. Hybrid energy systems are often modeled to achieve the lowest levelized costs of electricity (LCOE) by avoiding undersized or oversized components (He et al., 2017). Using solar and wind resources potentially reduces the LCOE by 20 % and attains a renewable energy (RE) fraction of 49.9 % in 1,785 islands globally (Blechinger et al. 2016).
Integrating different energy resources, like solar PV, wind, and hydro is used to ensure reliable power to the rural community loads. Hybrid power systems offer sufficient power supply for the rural villages by providing alternative supply for the intermittent nature of renewable energy resources. Hence, intermittency of renewable energy resources is a challenge to electrify the rural community in a sustainable manner with the different renewable energy resources (Kharchenko et al. 2019;Koneru et al. 2019;Assaf and Shabani 2019). Energy is one of the most important considerations for every nation's expanding future. Energy is by far the most valuable commodity on the planet, and a vast quantity of energy is extracted, transferred, transformed, and consumed on a daily basis in our global civilization. Global energy consumption is growing all the time. Today's worldwide energy production is heavily reliant on fossil fuel resources such as oil, gas, and coal, accounting for 83% of total global energy output. These resources are scarce, and their usage contributes to global warming by releasing greenhouse gasses such as carbon dioxide into the atmosphere. The perceived risk of utilizing fossil fuels has influenced interest in renewable energy. There is an increasing need for energy from renewable resources such as wind, solar, geothermal, and ocean to offer a sustainable power output in the future while also being concerned about global warming.
The sun is the source of life on our planet and, in certain cases, the fuel for most renewable systems. Photovoltaic and solar thermal devices, as well as solar thermal power plants, directly transform solar radiation into usable energy. Each square meter of the sun's surface releases 63.1 MW of radiant power, which means that merely one-fifth of a square kilometer of the sun's surface emits enough energy to meet the whole world's main energy need. Only a small portion of this energy makes it to the Earth's surface. This resource has the potential to fulfill the world's energy needs (Sanjida Moury, R. Ahshan, 2010). Solar energy is the radiant light and heat from the Sun collected using a number of technologies such as solar water heating, photovoltaics, solar thermal energy, solar architecture, molten salt power plants, and artificial photosynthesis (International Energy Agency, 2011). According to one theory, humans may have used sun energy as early as the seventh century B.C. When we go back in time, we can see that people used magnifying glass materials to light fires with sunlight. Later, in the third century B.C., the Greeks and Romans used mirrors to harness solar power to light torches for religious activities (Richardson, 2018).

Literature Review
Several countries have started to shift towards renewable resources based on geographic location and local resources (Akrami et al., 2020) Renewable energy sources (RE) are the best option available to meet the demand for electricity. The main sources of RE based systems are solar PV systems, wind power generation systems, fuel cells (FC), micro-turbines etc. Solar energy is considered a reliable, promising and profitable energy source. It has various advantages such as pollution-free, long life, low maintenance etc. (Gupta et al., 2016). Moreover, the generation of electricity from renewable energy sources integrated into a smart grid system can be one of the best choices for future energy security. (Choifin et al., 2021) Renewable and alternative energy has great potential benefits to replacing dependence on fossil fuels, and progress bringing it into the mainstream slowly in most developing countries (Vaka et al., 2020). According to global data, more solar photovoltaic (PV) capacity is being added than any other generation technology, making solar the world's preferred new source of energy generation. In 2016, around 73 gigatonnes of net new solar PV capacity were added globally. According to Rystad Energy, renewable energy installed capacity in the Asia-Pacific area would increase from 517 GW in 2020 to 815 GW by 2025. Solar energy will drive this expansion, with regional capacity nearly doubling from around 215 GW to 382 GW during the same time span. Energy transition was already on the increase in Asian nations prior to the Covid-19 epidemic. Clean energy infrastructure investment in the region has been significant in order to minimize carbon emissions through lower-cost technology and economies of scale (Daniel Baker, 2021).
Taking the West Lushan highway low-carbon service area in Jiangxi Province of China as the case study, it was proved that the reduction of the cost by electricity savings of the solar system was huge. The economic effect of the solar systems in the West Lushan highway service area during the effective operation periods was also calculated and proved very considerable (Qin et al., 2015). The Philippines is making a significant stride to become energy independent by developing more sustainable sources of energy. The recent Calatagan Solar Farm project in Batangas is set as a benchmark of the data for investment in RE, as this project is the latest RE project in the Philippines and has similar geographic features to Palawan; hence, investment cost estimations are up-to-date and relatively comparable. (Agaton & Karl, 2018)The 132.5-megawatt Cadiz solar power plant created by Helios Solar Energy Corp., a joint venture between Thailand-based Soleq Solar Co. and Gregorio Araneta Inc., was the largest operating project in the Philippines at the time. Solarplaza further mentioned that in March, indigenous business Solar Philippines began construction on a 150-MW solar facility in Tarlac, making it the country's largest solar power project to date. In addition, Solar Philippines has established the country's first PV module plant in Batangas. Solarplaza estimates the Philippines' installed solar power capacity at 900 MW as of June 2017. Solar power, according to the International Energy Agency, is becoming the most cost-effective source of additional energy generating capacity in many nations, particularly in Asia. The IEA predicts that, over the next 25 years, renewables and natural gas will meet the world's expanding energy demands first, as rapidly falling prices make solar power the cheapest source of new electricity generation. Solar PV systems are expected to dominate new generating capacity, owing mostly to the technology's growth in China and India (Domingo, 2018).
Certain solar technologies necessitate the use of rare elements in their development. This, however, is mostly a challenge for PV technology rather than CSP technology. Furthermore, it is not so much a lack of known reserves as it is an inability of existing products to satisfy future demand: many of the rare elements are byproducts of other processes rather than being the subject of concerted mining operations. Recycling PV material and improvements in nanotechnology that increase solar-cell efficiency might both help raise supply but discovering material alternatives that are more abundant could also play a role. The one environmental disadvantage of solar technology is that it contains many of the same toxic chemicals as electronics. As solar energy gets increasingly prevalent, the issue of hazardous waste disposal becomes more difficult. However, provided that the difficulty of safe disposal is overcome, the lower greenhouse gas emissions offered by solar energy make it an appealing option to fossil fuels (Matthew Johnston, 2021). Solar energy has the benefit of being a more sustainable alternative to fossil fuels. While fossil fuels have an expiry date that may be approaching, the sun is expected to last at least a few billion years. In comparison to fossil fuels, solar energy has a far lower environmental effect. Its greenhouse gas emissions are negligible because the method does not require any fuel burning. Furthermore, while concentrating solar thermal plants (CSP) are relatively inefficient in terms of water usage depending on the type of technology used, the right technology significantly increases efficiency, whereas photovoltaic (PV) solar cells do not require any water when generating electricity. Because the sun shines all over the world, every country is a potential energy generator, providing for greater energy independence and security.
Solar energy not only promises national security and independence; solar panels may be put on individual residences, giving electricity that is not dependent on being linked to a bigger electrical grid. One of the most serious issues with solar energy technology is that electricity can only be created when the sun is shining. As a result, the supply might be disrupted at night and on cloudy days. The shortfall caused by this interruption would not be an issue if there were low-cost methods of storing energy, as excessively bright times can actually yield extra capacity. As the worldwide capacity for solar power grows, nations such as Japan and other global leaders in solar energy technology are concentrating on building appropriate energy storage to address this challenge. Another problem is that solar energy may use a substantial quantity of land, causing land degradation or wildlife habitat loss. While solar PV systems may be attached to existing structures, bigger utility-scale PV systems may require up to 3.5 to 10 acres per megawatt, while CSP facilities may require up to 4 to 16.5 acres per megawatt. However, the impact can be mitigated by locating plants in lowquality regions or along established transportation and transmission lines.
Energy is essential like food and water. Everyone around us requires energy. The earth's population has grown through time, which is directly proportional to the amount of energy consumed. All imaginable devices and equipment require some form of energy to work. With the depletion of fossil fuel supplies, it is vital to discover feasible renewable energy options that can reduce reliance on fossil fuels.
The Solar Off-Grid Power Inverter is a more efficient, eco-friendly, and reliable source of energy. This study will address these three (3) concerning issues: 1. The lack of utilization of renewable energy to power up and supply the entire Electrical Engineering building of Don Honorio Ventura State University 2. Appropriateness of the roof for solar panels 3. Location of the Electrical room that will house the components The purpose of this study is to generate electricity by utilizing solar power panels and making use of solar energy to supply the whole Electrical Engineering building of Don Honorio Ventura State University. The goal is to reduce the amount of non-renewable electricity that is allocated for the entire building, at the same time advocating the use of renewable sources of energy demonstrating how functional and beneficial it is in the long run for the earth, people, and future generation. Also, the use of solar PV systems will act as a way to show the whole Electrical Engineering Department that they are committed to the environment and could be a big stepping stone to future Renewable Energy projects throughout the Department and even the whole University.
The study will focus on the suitability of producing and storing Solar Energy using a Photovoltaic system and an Off-Grid Hybrid Inverter. The study will be conducted in the Electrical Engineering Building of Don Honorio Ventura State University-Main Campus, Bacolor, Pampanga. The maintenance of the solar panels and other equipment is not included in the study.
This study provides numerous implications, as well as potential beneficiaries like the following:  For researchers -Given that the researchers of this study are all electrical engineering students, the study will help the researchers to unravel the welfare of green energy sources and discover enhanced methods of generation of electricity.  Don Honorio Ventura State University. The outcomes of this study will help increase and encourage the application of a renewable source of energy to produce electricity in Don Honorio Ventura State University (DHVSU), specifically the Electrical Engineering building, promoting more environmentally friendly advanced methods in accumulating natural resources.  Field of Engineering. It will contribute to the studies and experiments regarding this matter in the sense that this study will provide additional information when addressing issues regarding utilizing renewable resources to attain electrical energy that is environmentally friendly.  For future researchers -The study will help the future researchers for it will be a guide or basis for them in their future studies. Also, it may help them in the study of their related literature because this research contains information that will be relevant to their research.  Other Universities. This study will pave the way and motivate other universities to make an effort to take advantage of the natural resources that we have to promote a more environmentally friendly method of attaining electricity.
This conceptual framework serves as the guide for the researchers to collect and analyze the relevant data needed to conduct the said study. The researchers will gather the data necessary from the Off-Grid Hybrid Inverter taking into account the efficiency of the solar, its cost-benefits, and the effects of the building energy consumption. Through building profiling, the researchers will identify the total measurement of the roof area, the total electricity load that will be needed to supply the electricity demand, and the availability of the building. This study will determine the differences in the monthly expenses and savings between using an Off-Grid Hybrid Inverter and an electricity generator.

Methodology
The figure below exhibits the entire procedure that will be conducted in order to accomplish the study. The shown process will be utilized as a guide to present the course of action of the researchers throughout the whole research. It includes the data gathering, analysis of gathered data, implementation of the study, and evaluation of the whole procedure and outcome. and evaluation of the whole procedure and outcome.  Table (1) illustrates the kilowatt-hour per day of energy consumption of each appliance in Don Honorio Ventura State University's Electrical Engineering Building. The first column shows the electrical appliances which can be found in the Electrical Engineering Building. The second column shows the quantity of the appliances. The third column shows the kW of each appliance. The fourth column shows the working hours. And the last column shows the energy consumption of each appliance by multiplying Quantity, Power, and working hours. The highest energy consumption is from ACU 2HP with 110.4kWh.
The researchers were able to compute the total power consumption of each appliance by using the said formula:

Power = Quantity x Appliance Rating (kW)
However, to calculate the total power consumption for the ACUs, the researchers utilize Table (2) to obtain the current and voltage of the ACU (2HP) and ACU (3HP). With these, the researchers computed the power consumption of each ACU through the said formula:

Power = I (current) x V (voltage)
After the computation of the total power, the researchers have summed the total power for each appliance to obtain the total power of the Solar PV System Design. With these, the number of solar panels needed was calculated using the formula: The researchers utilized the formula below to calculate the amount of peak power (Vivint. solar, 2022).

Peak Power per Solar Panel = Solar Panel Rating(Watts) x Average Hours of Sunlight x Coefficient Installation of Solar Panels
Peak Power = 400 x 5.38 x 0.75

Peak Power = 1614 Wh
To translate this into the more familiar kilowatt hours you're used to seeing on your electric bill, simply divide by 1000.

Peak Power = 1.614 kWh per solar panel
Peak power is defined as a percentage of the total operating time. A typical average hour of sunlight is 5.38 as shown in Table (3). The selection of power supplies is based upon the expected maximum total system power calculated as Volts Amps Watts. In some applications, looking more closely at the peak current or peak power rating of the module may provide a significant cost saving (TDK-Lambd, 2022)

Fig. 3. Latitude and Longitude of DHVSU Electrical Engineering Building
The latitude and longitude value for Electrical Engineering Building is 14.997734, N 120.655491 as shown in Figure (3). The calculation can be done as follows using the formula from the study of (Yilmaz, 2018).
As a result of this calculation, the solar panel should be directed to the South at 13 degrees angle for use throughout the year in the EE Building position. To get the most from solar panels, you need to point them in the direction that captures the most sun. It is simplest to mount your solar panels at a fixed tilt and just leave them there. But because the sun is higher in the summer and lower in the cold season, you can capture more energy during the whole year by adjusting the tilt of the panels according to the season. "PV Module Angles", Home Power recommend an angle that puts the panel perpendicular to the sun's rays at noon. (Landau, 2017). found that the 1754mm x 1096mm dimension is appropriate and best fits the present 28m x 15m roof of the building as this will only require sixty-six (66) solar panels upon installation and gives the maximum surface area exposed to sunlight leaving only 1m in each side of the roof space. Table (4) above shows the electrical data of various TrinaSolar Vertex S Solar Panels that are compatible and recommendable to be used in garnering renewable energy to supply the DHVSU Electrical Engineering Building. Through comparison, the researchers found that the TSM-DE09 is advantageous as it gives the most peak power in watts compared to the other models at the same time reducing the number of solar panels to only sixty-six (66), avoiding the need to require additional panels to make up for the power lost if other models such as the 390W and 395W were to be used. Also, the power output tolerance is similar in all models which makes the 400W model ahead of the others. The module efficiency varies greatly between the TSM-DE09 400W which has 20.8% and the TSM-DE09 390W which has 20.3%, with a difference of 0.5%. With this, the percentage of sunlight that reaches the solar panel is higher meaning that more solar energy is converted into electrical energy and the roof will require a lesser number of panels to meet the required amount of usable electricity to supply the DHVSU Electrical Engineering Building. The open-circuit voltage for TSM-DE09 400W is at 41.2 V, having a 0.4V advantage compared to other models therefore, it can hold greater maximum voltage available from a solar cell. Table 5. Performance of LUNA2000-5-S0, LUNA2000-10-S0, LUNA 2000-15-S0 Table (5) shows the similarities and differences in the specification between the three battery models of Huawei LUNA2000 Battery. The researchers established that the dimensions between the batteries are identical in terms of width and depth and differ only in their heights; hence, it does not crowd the room that will house the electrical components as the batteries will be positioned on the ground. The researchers also found that these batteries share the same specifications in terms of battery module energy, operating voltage range, and nominal voltage range both in single-phase systems and three-phase systems. Although they vary in terms of a number of battery modules wherein the LUNA2000-15-S0 has three (3) therefore having the highest battery usable energy of 15kWh which is three times greater than the LUNA2000-5-S0 which will provide greater storage for the energy converted, this energy stored will then be used to power up the lighting outlets in the evening during the off-grid system. The LUNA 2000-15-S0 along with the LUNA 2000-10-S0 share the same maximum output power of 5kW and peak output power of 7kW, 10s which is substantial compared to LUNA2000-5-S0. However, the LUNA2000-15-S0 is still preferable and at an advantage due to possessing the highest battery usable energy.   (6) shows the specification of the String Inverter SUN2000-30KTL-US that the researchers will utilize to convert the total power generated from the sixty-six (66) solar panels from DC to AC. The researchers have selected the SUN2000-30KTL-US as it has a maximum DC power of 30,000W, rated AC output power of 30,000W, and maximum AC output power of 33,000VA therefore, it can convert the 26.584kW generated by the sixty-six (66) solar panels installed. The inverter in terms of its dimension of 550×770×270 mm requires minimum space in the electrical room. The researchers also commend the SUN2000-30KTL-US for having a high efficiency since during the conversion some of the power can be lost as heat. Thus, with a peak efficiency of 98.6%, there will be less amount of power lost when power is being transformed from DC to AC.

. Photovoltaic Panels Layout
In the Electrical Engineering building, there is a significant amount of space enough to install a PV system to produce energy to supply the building. The installation of PV modules on the rooftop will reduce the heat waves penetrating the whole building that is coming from the rooftop. The solar PV arrangement is methodically planned to avoid any possible shadow cast by nearby structures or trees. The rooftop viewpoint of EE Building is illustrated in Figures 5 and 6. The strings are arranged in such a way that there is no shadow from one string to another. This specific design for the installation of solar PV has a total roof area of about 364m².
In this illustration, it can be seen how a PV panel is connected to create a string. The researcher used a number symbol to designate the connectors to easily show how the wiring layout must be connected to the inverter. Each PV panel is 48.9V-DC and when 11 PV modules are connected in series the DC-Voltage value of each string is 537.9V. The 537.9V is within the amount of voltage that can pass which is 0-1000V-DC. A common bus tie is used to interconnect the 6 strings PV module to 12 wires into 2 wires.

Fig. 7. Photovoltaic Panels Single Line Diagram
The researchers proposed 66 photovoltaic modules divided into 6 strings with each group connected in series. The researchers also designated each group a surge protection device 800V-two pole for protection and isolation of equipment. The researchers added a 15kW-hr battery to sustain a lighting load in the evening. After the DC side, there is an additional 30kW inverter based on the computed required energy consumption consumed by the consumers to invert the generated power into AC. On the AC side, coming from the inverter to the electrical loads a surge protection device is added for the safety of electrical consumers, and also the inverter itself. The specification used in the surge protection device and wire sized in the AC side of the inverter is based on the already existing computed and implemented design of the EE building. Figure 8 illustrates the outline of the proposed electrical room designed in AutoCad. The room was originally the Labtech room. Due to its good ventilation and spacious area, the researchers have ideally selected this room to be converted into the electrical room where the required equipment and machinery needed to function the Solar PV system will be stored. In the diagram, it can be seen where the battery and hybrid inverter will be placed. With the slim design of both electrical components, the room remains spacious for continuous circulation of significant amounts of air and open for additional components to further improve the Solar PV system.  The researchers were able to compute the payback period of 5.55 years by utilizing the formula adapted in the study by Shujauddin et al., (2020). The term payback period refers to the amount of time it takes to recover the cost of an investment. Simply put, it is the length of time an investment reaches a break even point (Kagan, 2022). Upon the completion of the project, the researchers have found that it will take 5.55 years before the total expense of Solar PV System design will be earned back.

Conclusion
Renewable energy is naturally replenished on a human timescale, it comes in several forms all of which can be converted to another form of energy such as electricity. With the present situation in the Philippines, The lack of utilization of renewable energy to power up and supply the entire Electrical Engineering building of Don Honorio Ventura State University encouraged the researchers to conduct this feasibility study, using Solar Hybrid Inverter in Don Honorio Ventura State University's Electrical Engineering Building to supply the electrical energy to needs to power up the whole building. Materials that provide the ability for the human population to make use of renewable energy have been available and affordable in markets that are accessible around the world. The researchers were able to comprehend the importance of the appropriateness of the roof for solar panels to obtain the maximum solar power available, bringing more than enough electrical energy to supply the whole school. With the completion of this study, the researchers were able to estimate the number of years to gain back the investment spent on the project and accomplish a Solar PV System Design that will provide a long-term source of energy to supply the Electrical Engineering building of Don Honorio Ventura State University. The electrical energy converted from solar energy will provide improvement to the Electrical Engineering Building in terms of functionality wherein appliances will no longer consume massive amounts of non-renewable energy. This will also enhance the facility that is available to the Electrical Engineering Department. Lastly, the accomplishment of the Solar PV system will serve as a sample to produce future Renewable Energy projects that will further improve the University and its students.
This study has several limitations and there are things that the researchers want to recommend the following:  The researchers suggest increasing the capacity of the solar system to save more energy. By expanding or selecting an area where there is greater space for the installation of the solar panels, Along with the improvement of the electrical components such as the battery and inverter to produce greater total output power.  Future researchers are recommended to conduct more in-depth research of past studies relating to the feasibility of solar-powered buildings using an Off-grid Hybrid Solar Inverter to further enhance the reliability and validity of the study.  Given that this study was performed during the COVID-19 Pandemic, it is highly suggested that it be conducted after the pandemic restrictions to make the procedure of data gathering much more accessible and faster.  Lastly, the researchers advise other researchers to study the DHVSU Electrical Engineering Department Goes Green: Feasibility Of Solar-Powered Building Using An Off-Grid Hybrid Solar Inverter to aid in their own study that will contribute to the advocation of renewable energy.