Natural Environment

To demonstrate our engineering ability to design for environmental conditions, I am using a design that I worked on many years ago. It's the most straight forward example I have to describe the products that we typically improve by design, and the environmental elements that we take into account.

The example is that of power generation without fossil fuel. For those that have read our 'About us' page, this will be familiar to you, as it is a parabolic dish with the Stirling engine.

I am using this as an example, as it was where my interest for designing for the natural environment originated - 'The inspiration'. I'll recap for those of you that are not familiar. The project was power generation by using the heat of the sun's rays to run a Stirling engine (A Stirling engine has a similar construction to an internal combustion engine, typically found in petrol and diesel cars, except that it runs on heat, not fuel.)

The Stirling engine was mounted on a parabolic dish. The parabolic dish was a concave mirror that reflected the sun's rays onto the heating element of the Stirling engine.

(And here are the challenges of the project to enable this design to operate reliably and resiliently in the natural environment, which I have not mentioned on this website anywhere else.) The curvature of the parabolic dish was important so that the sun's rays were reflected onto the heating element of the Stirling engine (the heating element coincided with the focal point of the parabolic dish).

The challenge was to ensure that the curvature of the dish did not change with ever changing temperatures. As, if it did, the focal point would move and the heat concentrated on the heating element would move and consequently the heat could burn a hole through the heating element, damaging the element and releasing the internal system gas into the atmosphere. Therefore, the design of the trusses of the parabolic dish had to compensate for a temperature range of 0°C to 45°C.

This is a prime example of what we take into consideration when we design for the elements of the natural environment. Not just what's seen, but also the unseen.

Now for an example of how we protect the natural environment from pollution. Using the Stirling engine as an example again, as mentioned in the about us page, this was the main concern of mine, and the main inadequacy of the design - the drone of the Stirling engine.

The noise radiated from the Stirling engine was not ideal for the location in which this project was designated, as it was for a game reserve. As mechanical and acoustic engineers, we have the skills and knowledge to mitigate noise at the source. For the Stirling engine, we would change the design slightly by moving the engine itself to below ground level, isolating the engine vibrations from the ground and shielding the radiated noise from travelling above ground. (The heating element will still be mounted on the parabolic dish, and the heated gas routed to the Stirling engine and back to the dish).