What Would Happen if Photovoltaic Panels on Our Roofs Track the Sun?

Livio Mariano_20459

Introduction

It's been a few months since I have moved into a new apartment and often while drinking my cup of espresso coffee, through the window of the kitchen, my eyes fall on the roof of my neighbor. The roof is oriented to the south and solar panels, both thermal and photovoltaic, are settled on it. They are fixed on the roof like most of the panels installed on residential houses.

Challenge

It's now a while that I wonder: what if panels track the sun like a sunflower?

Especially considering the increasing cost of energy, it's interesting to quantify how much additional energy a solar tracker system can generate.

View from the window of my kitchen (apart from the sunflowers unfortunately)

Solution

To evaluate the benefits, I set up a model using Altair® Activate™ where the scenarios with fixed panel, panel with variable tilt (1-axis actuation) and panel with variable tilt and orientation (2-axis actuation) are compared. Below the Activate model.

Living close to Turin and planning to install photovoltaic panels in my next house (this maybe why my eyes always fall on my neighbor's roof - yes I'm a bit jealous if you are wondering ????-), I have used annual data related to this city available with a time resolution of 5 minutes. Data comes from Meteonorm database which provides worldwide irradiation data from which I could apply the isotropic sky model [1] to calculate the total solar irradiance on the tilted panel. From this information, considering the surface of the panel and its efficiency, it's fairly easy to estimate the electric power production (hence also the energy).

I focused the analysis on just one photovoltaic panel of 2 sq.m. and efficiency 25% . This is a very good efficiency considering that the average today is about 20% but my good friend Alberto Piovan (expert on energy transition) shared that the best panels produced today may already reach efficiency >30%.

The fixed panel is in the optimal configuration (considering the location), hence oriented to South and with tilt angle of 30 deg.

Simulation run time is < 6 seconds to simulate the whole year (super fast considering that the max time-step used is 60 seconds).

Below the diagram of the power production. The panel has a peak production of about 450 W. When we zoom-in, each peak in the chart represents a day and we can notice that increasing the degrees of freedom from 0 (blue) to 1 (red) and 2 (green) of the panel, we achieve a more constant electric power production along the day.

This leads to an increase of the total energy production as shown below.

The trends show rightly a higher slope during the second and the third quarters of the year when the solar irradiation is stronger.

Evaluating the performance at the end of the year with respect to the standard scenario (with fixed panel), results show that if we vary:

1- only the tilt angle, we get an increase of about 12% in energy

2- both, the tilt and the orientation angle, we get an increase of about 49% in energy

The first option doesn't bring a high advantage (but let's consider that we are comparing with a fixed panel installed in the optimal configuration).

The second option looks much more convenient but would require a higher investment to actuate a 2-axis system. In addition, it requires more space and there could be issues for the installation on roofs based on local policies.

Considering that the roof of my new house has already an optimal orientation, based on the results I'll drop the idea to use actuated panels!

Value

The simulation performed can be easily extended adding also the electric consumption of the building based on specific usage profiles. This can help to better dimension the number of panels and in case the accumulator. A cost analysis can be also performed having available all the needed bricks: cost of the panels, cost of the purchased/sold energy...

[1] P.G. Loutzenhiser a,b,*, H. Manz a , C. Felsmann c , P.A. Strachan d , T. Frank a , G.M. Maxwell Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation. Solar Energy 81 (2007) 254–267

M Bhupesh

Do you have any ideas on printing solar cells on Ultra thin layers with stickers?

It could stick any kind of solid surfaces such as infrastructures, metals, woods and other solid materials to generate the power from the natural energy sources. Being light weighted, easy to transport, no need for space allocations or warehousing the products. Print the products whenever you require,

It could be a revolutionary products in creating powers from natural sources. Also, it will full-fill our global needs in power generation from this product itself.

Appreciate your comments and encourage us to do some more research*

Thanks!

M Bhupesh

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