Racking up efficiency and affordability of solar systems atop roofs

Ulysses De Waegemaeker

Back in 2018, a Paygo Solar Home System (SHS) distributor in Tanzania realised that the solution being used to support tier 1 solar panels was less than ideal: not only was it badly perceived by clients, but it only consisted of wires and wood pieces. Needless to say, it was inadequate to configure the photo-voltaic (PV) modules at an optimal position in order to allow the system to receive as much solar radiation as possible and improve the efficiency of their distributed Paygo solar home systems. The drawback resulted in power-intensive clients complaining about the charge recovery speed not meeting their expectations even during the sunniest days.


Former improvised solution: a piece of wood attached with wires

 

One after another, the claims started to reach our client’s after-sales team. In need of a prompt solution, the distributor reached out to Solaris Offgrid’s Product Development Services to assess the situation. Given our former experience in the field, they entrusted us to engineer a panel mount that would be easy to deploy in already installed systems, while remaining affordable and simple enough to be implemented smoothly within the upcoming systems to be sold.

For several weeks, we had to climb on many different roofs to get a first-hand understanding of the multiple factors that can alter the PV efficiency. After measuring diverse variables, such as inclination, orientation, temperature, wind speed, roof distance and materials, it was more than clear for us that our client was in need of a reliable solution for solar panel mounting on different roofs.


Climbing on roofs to measure PV inclination

 

At a first glance, standard and already commercially available PV mounting systems would seem an optimal solution to set the solar panels at the right roof inclination and distance, allowing to lower the PV temperature, protecting it from humidity and, most importantly, letting the PV directly face the sun for a longer period during daylight.

Standard commercially available PV mounting systems

 

However, being aware of the local context, we were facing a dilemma: the bulk price (~10USD) of this hardware piece was equivalent to the end customer’s weekly average income, which would naturally represent a significant and prohibitive cost increase, considering they paid their SHS systems on a pay-as-you-go basis.

We sat down with our client and decided to dismiss standard solutions. Instead, we would move forward with a custom design which would both adjust to the customer’s budget and be easy to transport for technicians.

It also seemed challenging to provide a universal solution for different panel configurations, given distributors may have multiple PV suppliers, which translates into variations in frame design. Luckily for us, in Tanzania we found different panels of the same power capacity, thus we were able to test the fit with all of them.

Now it was time to get down to work. After assembling multiple prototypes and performing different validation rounds, we came up with an affordable solution that could be implemented even without any complex setup or tooling investment. It consisted of solar panel legs with four different configurations to meet 15º degrees in relation to the ground plane; an optimal inclination to improve efficiency at near the equator latitudes.


Our proposal: solar panel legs with four different configurations

 

Moreover, an aluminum pipe working together with an ABS tube would be the main components set by the installer to obtain the right PV inclination even on the steepest roofs (55º). At the bottom of the mount leg, a rubber tip is included to avoid uncomfortable noises when sitting over metallic roofs. On the upper side, a durable metallic thread compatible with most PV mount holes, which allows to adjust the solar panel in a simple way, with no special tools or training being needed.

A total of 40 samples were produced and shipped to Tanzania, where we deployed a dozen of them to gather some feedback on durability and ease of installation. As we were setting up the newly developed solution, the installers were truly excited to see how these easy-to-carry mounts would completely simplify their work processes, as they would no longer have to put together an improvised and rustic mount on their customers’ roofs. 

Along with the developed solution, we prepared and provided our customer with an easy-to-follow instruction guide, summing up the optimal PV conditions that an installer should pursue with a step-by-step verification process to reach the most efficiency in different scenarios.


Testing our panel mount with local installers

While the other SHS distributors in the region kept using improvised wooden alternatives or even only wires to support tier 1 solar panels, our client was now one step ahead, providing a cleaner and more flexible setup that let their customers’ solar home systems receive as much sunlight as possible and, naturally, increase PV efficiency. We were able to address not only our client’s specific needs, but ultimately developed an affordable and robust solution that could fit roofs across Sub-Saharan Africa. It was just the ideal panel mount for last-mile operations that installers were not expecting but truly needed.

Ulysses De Waegemaeker is Industrial Engineer at Solaris Offgrid

Source: Solaris Offgrid

 


 

 

 

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