Technology and Sustainability
SunOK is a small company with a longing for excellence and an eye on perfection. We aim to have an impact in society, contributing on one side to the adoption of cleaner technologies and a better interaction between humankind and the environment, and on the other side, positively impacting people’s lives through better nutrition, lower expenses, more free time, and a closer and healthier contact with nature.
This is the driving force behind all our technological developments, that came to fruition on the Suntaste, by not doing things the usual way.
Research and development
Solutions beyond expectations
At SunOK, we are passionate about creating highly-efficient and practical solar solutions that are both attractive and enjoyable to use. Our mission is to provide renewable energy options to our customers, meeting and exceeding their expectations. To achieve this, we are constantly experimenting with innovative materials and features that undergo rigorous testing to ensure they meet the exacting standards of our clients. Seeing the satisfaction on our customers’ faces is our greatest reward.
We are privileged to be the meeting point of leading industry experts, including the following:
Manuel Collares Pereira, PhD, an expert in renewable energy and advanced optics who is responsible for our ovens’ superior efficiency.
Our team of engineers and product designers, always prone to thinking outside the box, and use cutting-edge 3D modelling design tools to bring new ideas to life.
Our network of technology-leading manufacturers, which provides us with world-class standard materials and proprietary design parts.
Metrology
State-of-the-art technologies and methodologies are extensively used by SunOK, to guarantee that the end product meets the expectations of the most demanding users.
On the left side it can be noted how we use thermal imaging to understand how the excellent insulation properties of cork allow the body’s outside temperature to remain at safe levels whilst the pots attain 118ºC/245ºF.
On the pictures to the right, one might see how we use simple control technologies to ensure the perfect fit and finish that are quintessential for our products.
Cork
We’re based in Portugal, which is the world’s largest producer of cork, despite being a small country. you can find more about this outstanding material, here.
Cork is one of the best thermal insulation materials with uses that range from wine stoppers and construction materials to thermal tiles for use in NASA’s new heavy-lift rocket, the Space Launch System (SLS). It made sense, therefore, to consider it for insulating our ovens.
Cork is not, however, a traditional engineering material: it lacks homogeneity, being formed by grains (clusters of cells); it sports high elasticity, making it difficult to obtain precise dimensions; and, being an organic material, it’s very sensitive to temperature and humidity.
For these reasons, we first toyed with the idea of using a combination of cork with other structural materials, even considering a layered composite of carbon fiber and cork, as pictured above. Needless to say, cost considerations led to the abandonment of that idea at a very early stage.
It was only after machining the first cork parts that it became clear that, by using cork agglomerate with an inert polyurethane resin as bonding material, we could achieve the dimensional precision required for the high-quality product we wanted the Suntaste to be. Surface finishing was still very rough at that time, as can be seen from one of the very first parts we made, pictured on the left.
And that is how we converged to cork molding, which enabled us to achieve the required dimensional accuracy, and the smooth and supple finishing that, nowadays, makes everybody want to touch the Suntaste’s surfaces.
Friction Hinge
The Sun Cook (more about it here) was our first model and used telescopic rods to enable the positioning of the lid’s reflector at the right angle. This required two-handed operation and was felt by us as a too clumsy way of doing it, therefore not compatible with the higher standards we wanted the Suntaste to achieve.
After facing the fact that the friction hinges available on the market where mostly designed for laptop computers and not at all adequate for fixing into a cork product, we took the (hard) task of designing and developing a completely new piece of kit that is one of the most appreciated subsets in our solar cooker.
This has been one of the most difficult developments on the Suntaste project, a source of many worries at the development stage and a constantly upgraded feature.
Hopefully, after many design woes and prototypes’ testing, the earlier mass produced version of it proved as smooth and reliable as required, thus sparing our first customers from the harsh participation in the learning curve.
The subsequent versions had more to do with easing assembly and improving the looks than any functional aspects. The torque calibration and smoothness of operation, which were our strongest aims for it were guaranteed since inception and are much appreciated by Suntaste users around the world. This could only be achieved with very tight tolerances, under five cents of a millimeter, requiring rigorous manufacturing and an effective quality management.
The latest version, pictured right, is the epitome of it and will remain one of the hallmarks of the Suntaste, with our continuous improvement instinct now focusing on other parts.
Reardoor
Pressure and temperature are two factors to consider when making an oven, and the Suntaste’s first cork backdoors had trouble keeping it all in place. That required some ingenuity from our side to make it able to withstand the stress, ending with a composite door, where cork is reinforced by a metallic core that drastically increases its stiffness.
That made us delve deeply into moulding technologies to guarantee the right layer’s positioning across the thickness, thereby ensuring the perfect closure that is essential for the Suntaste’s high-performance when cooking.
Glass
The Suntaste sports two glass-panels for better insulation, and recurs to high-transparency glass to minimize energy losses. These are much more transparent than normal window glass, and are tempered to avoid any hazard to our customers. Being this a component whose quality is difficult for SunOK to entirely control, we source glass only from top-tier European manufacturers. The result shows in the performance of our cookers.
On the other hand we were well aware of the energy losses that occurred on our first model, due to the condensation that formed under the internal glass, which, if not timely cleaned could start reflecting solar rays away from the cooking compartment. This effect is clearly visible on the picture on the left.
This was addressed on the Suntaste by placing the glass panels at an angle such that the water droplets resulting from condensation slide down, thereby cleaning it without requiring any user intervention. The effectiveness of this solution can be seen on the picture to the right.
The two ovens pictured were being tested simultaneously under the exact same conditions.
Packaging
We’re all for sustainable, recycled or recyclable materials. For this reason the Suntaste had an all carton protection: the external box was lined internally with cardboard pillows providing good protection against impact (see it on the right).
This was not enough, though, to deal with the harsh reality of parcel deliveries, with the resulting broken ovens and rightful customer complaints forcing a re-evaluation of the environmental friendliness of our packaging. As a result we decided to invest in a foam injection machine filling the external carton around the product for optimal blocking, shock absorption and bracing. The result is shown in the second picture on the right.
The resulting foam, though less environmentally-friendly than carton, when considered over the life cycle of the product, and taking into consideration the eventual accidental breakups, proved to do more for sustainability than our first and more obvious option. We’re always learning…
