Calculating Solar panel efficiency:

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An efficient solar system is a must nowadays. However, the failure rates are increasing simultaneously. In such a scenario, regular cross- checking on the efficient working of the solar panels emerges as a feasible way out. This too has to be done carefully and accurately so as to get the best possible results.

A very common mistake occurs while users try to calculate the temperature coefficient of the system. Users often take into account the ambient temperature of the panels. This causes much deviation in the accurate reading of the temperature coefficient. If it is 40C outside, then the panels are almost over 65C. This changes the entire calculation thereafter.

  images1Underestimating the losses:

Another mistake happens when users unconsciously underestimate the inherent losses of the inverter. There are several ways by which the system loses its energy due to various technical or environmental factors. As a result the overall efficiency is disturbed and miscalculated.

Points to remember:

Generally 10% other losses are estimated whereas in reality they amount up to 20%. These include:

  1. Manufacturer’s Power Tolerance (1%): All separate panels have their own individual power tolerance. This gets summed up together as single entity when these panels are combined together in a solar system which results into an aggravated power tolerance altogether which is almost 1%.
  2. Temperature Losses (10%): It is important to note that solar panels don’t like to stay hot for long periods of time. The high temperatures do take a toll on their efficiency in the long run. This amounts for almost 10% losses in the overall efficiency of the system
  3. Dirt (5%): A lot of particulate matter like dust.etc gets trapped from the air surrounding the panels onto the panel’s glass surface. These particles block the sunlight reaching the panels. They cling to the surface and hinder the working of solar cells. This has come up as a major problem as it requires a lot of maintenance to fix this problem. It is responsible for 5% losses.
  4. Wiring Losses (2%): All the electric wires have a little inbuilt electrical resistance. This means that while electricity passes through the system, a small voltage drop is bound to occur. This reduces the power to some extent and sums up to almost 2% losses.
  5. Inverter Efficiency (4%): The inverter is that part of your system through which everything passes along. As a result the efficiency of the inverter will inevitably affect the output of the system and amounts for 4% losses.

These are the conditions which affect the efficiency of a solar system most commonly. However these are discussed on a general basis and results may vary in exclusive cases. There are many other factors like the angle at which the panels are inclined or the direction in which they are placed, which affect the power output.

Also, at least 1 month of accurate data is an essential prerequisite for making any judgements about the working of a solar system and we shall have to wait before we sound the bugle or the warning alarms. The performance of the solar panels will only be statistically valid after making recordings for a month or two.


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