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A Simple Step-by-Step Guide Reveals How Many Solar Panels Are Needed to Generate Enough Energy and Keep a 12,000 BTU Air Conditioner Running for 12 Hours Daily Without Any Impact on the Electricity Bill.
The idea of keeping an air conditioner running for 12 hours a day, for an entire month, without spending anything on the electricity bill, grabs the attention of those facing intense heat and looking for economical alternatives.
At first glance, the proposal seems like a distant dream, but the use of solar energy places this possibility at the center of the discussion.
In a video, the channel E4 Renewable Energies explains step by step how to calculate how many solar panels are necessary to achieve this goal. The channel claims that with three simple steps, anyone can follow the calculations without complications.
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Air Conditioner Consumption
The first step presented in the video is to identify the consumption of the air conditioner. The creator chooses a 12,000 BTU model from Mideia.
To find out the energy consumption of the equipment, he checks the label from Inmetro, which indicates an average annual consumption of 510 kWh.
He recalls that the agency changed its rules and now calculates consumption considering 2080 hours of operation. This means that the unit consumes, on average, 0.25 kWh per hour.
He rounds this figure for convenience and comments in a casual tone that no one buys an air conditioner to use “just a few hours,” except someone very economical.
He notes that everyone knows someone like that and proceeds to the main calculation. The projection considers the use of the air conditioner for 12 hours daily over the 30 days of the month. The result is simple: 0.25 multiplied by 12 and then by 30, totaling 90 kWh monthly.
He states that this will be the consumption to be supplied by solar energy since the goal is to allow the use of the unit without impacting the electricity bill. From there, the video moves on to the calculation of the energy generated by a solar panel.
Energy Generated by a Solar Panel
In the second step, the creator explains how to discover how much energy a solar panel produces in a month. He uses a formula for this calculation and warns that all the factors will be defined throughout the video.
According to him, the energy generated is equal to the power of the panel multiplied by the average daily irradiation of the installation site, multiplied by the system efficiency, multiplied by 30 days, all divided by 1000.
He reminds that there are various power ratings of solar panels available on the market and decides to use, as an example, a 600 W peak panel. He states that this will be the value used for the rest of the calculations.
The next piece of information to be defined is the solar irradiation, described by him as the “power of the sun” in the city in question.
He informs that this value can be found in the Cresc database and mentions that there is already a video on the channel explaining how to locate this information.
Then, he chooses Rio de Janeiro as a reference, stating that the city is hot and that there is no way to live without an air conditioner. The average daily irradiation in Rio de Janeiro is 4.93 kWh per square meter per day, which he translates as equivalent to 4.93 hours of useful sunlight.
With this, it is only necessary to define the system efficiency. He explains that this factor relates to the losses of the photovoltaic system, such as dirt, angle deviation, and losses in wiring. He states that the sector averages 25% losses, and therefore, the efficiency would be 75%, or in decimal form, 0.75.
With all the numbers defined, he substitutes the values into the formula. The calculation shows that a 600 W peak solar panel installed in Rio de Janeiro generates approximately 66.55 kWh per month. The creator highlights that this value corresponds to the monthly production of a single panel.
He comments that this generation allows moving on to the final step, where it will be determined how many panels are needed to meet the daily operation of the air conditioner. He also takes the opportunity to reinforce the request for subscriptions and likes on the video.
How Many Panels Are Needed
In the third step, the creator finally compares the air conditioner’s consumption with the solar panels’ production. He states that it is simply a matter of dividing the monthly consumption of the unit, which is 90 kWh, by the monthly generation of one panel, which is 66.55 kWh. The result is 1.35 photovoltaic modules.
Since this number does not exist in practice, he explains that it will be necessary to install two panels. He emphasizes that this result shows that just two 600 W peak solar panels allow the use of a 12,000 BTU air conditioner for 12 hours daily over the 30 days of the month, in the city of Rio de Janeiro, without cost on the energy bill.
He reinforces that this calculation varies from city to city due to differences in solar irradiation. Nonetheless, he comments on another interesting scenario: if the air conditioner were used for an average of 8 hours a day, a single 600 W panel would suffice for the consumption.
He also notes that with two panels, it would be possible to power two units for half the usage time, exemplifying with two air conditioners of the same capacity running for 6 hours each.
The channel states that these calculations show very advantageous possibilities but reminds that the video deals with a system connected to the grid of the utility.
For those interested in learning about autonomy in disconnected systems, he recommends another video on lithium batteries. He concludes by sending a hug and mentioning he will be back soon.
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