O Canal Solar A recent article was published highlighting the savings of over R$ 1,8 million generated by the solar power plant installed at the Hospital de Clínicas of UFTM (Federal University of Triângulo Mineiro).
In this context, the project implementation took place in a challenging environment, shortly after the start of the Covid-19 pandemic, which directly impacted the construction schedule as it involved a hospital unit.
According to Diego Otávio, Director of the Ascenário Group and the Imersol Network, and one of those responsible for the project, the circumstances at the time delayed the implementation schedule of the power plant.
“The first part of the plant began operating in mid-2020. Starting in July, the system began to gradually come online, initially with two inverters, until it reached 100% operation with all the panels by the end of October 2020, totaling 11 inverters,” he recalled.
Even with the temporary interruption of activities, the project maintained its technical and financial viability, a direct result of detailed planning carried out before the start of construction.
Still in the preliminary phase, the team in charge conducted a technical study to evaluate the main technologies available in the photovoltaic market, considering not only the initial investment, but also the system's behavior over time.
In this study, the following alternatives were analyzed: conventional central inverter, microinverters, and a system with optimizers and a central inverter.
Since the hospital is supplied with medium voltage, falling under the green time-of-use tariff, the analysis considered direct impacts on financial return, in addition to the physical limitations of the coverage, such as module orientation and structural interferences.
Diego explains that, although the system with a conventional central inverter had a lower initial cost, it proved to be less attractive in the medium and long term.
But according to him, the technology with the Solar Edge inverter with optimizer proved to be more suitable for the site conditions, especially to reduce losses associated with partial shading and dirt accumulation, common on the hospital roof.
These roof features, in fact, played a central role in the entire project design. The presence of antennas, parapets, and technical equipment already posed challenges to power generation, a scenario that intensified later with the construction of a new annex building, taller than the original structure.
Even so, the use of optimizers made it possible to minimize losses and preserve system performance.
Logistics
With the technology defined, the implementation phase brought significant practical challenges, especially in the logistics of installing the photovoltaic modules, positioned on the roof of a three-story building.
According to Wesley Amâncio de Melo, head of the Physical Infrastructure Sector, the equipment arrived on pallets with a high concentration of weight, requiring a careful distribution strategy to avoid structural overload.
"They arrived on pallets with 20 units per box, and they can't all be placed together because of the concentrated load. The concentrated weight could have damaged the building's structure," he stated.
In addition to logistics, the project required special attention to the system's watertightness, since some of the modules replaced existing fiber cement roofing tiles. Fine adjustments were necessary to ensure proper sealing and prevent leaks.
"Adjusting the sealing system to prevent leaks presented some difficulties, but in the end, everything was sealed five years ago without any water infiltration," he explained.
Electrical integration
With the challenges of the physical installation overcome, the focus shifted to integrating the photovoltaic system with the existing electrical infrastructure. To achieve this, adaptations were made to the hospital's electrical panels, allowing for direct connection of the inverters to the distribution systems.
“In connecting the system to the hospital facilities, we opted for a solution that links the inverters directly to the electrical distribution panels, located near the frequency inverters. The integration was carried out through adaptations to these electrical panels, connecting the circuit breaker-protected output of the inverter to the protection panel and, subsequently, to the power supply of the hospital's electrical consumption panels,” said Diego.
In areas with 380 V networks, the connection was made directly. In areas served by 220 V, transformers were used to match the output voltage of the inverters, ensuring safety and operational efficiency throughout the hospital complex.
I believe it would be important and interesting to give more visibility to Wesley, the person responsible for the infrastructure.
Performance
With the system now operational, the results have confirmed the efficiency of the technical decisions adopted throughout the project. Operational data indicate that the plant has been performing above initial projections.
Diego emphasized that the initial estimate projected an average generation of 45 MWh per month, but the operating history shows higher numbers, with an average of 52 MWh per month.
This performance was also directly reflected in the financial return on investment, where the initially projected payback period was exceeded, with the effective return occurring in approximately 51 months.
The result was also influenced, among other factors, by the utility company's tariff adjustments being above the average inflation rate, which increased the value of the energy saved over the period.
All performance is continuously monitored through Solar Edge, which allows for real-time monitoring and visualization of production and the issuance of automatic alerts, facilitating quick maintenance actions and ensuring the efficiency of the modules over time.
Deepen your knowledge:
Solar plant generates savings of over R$1,8 million for the UFTM Hospital
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