Let me introduce you to my first project as a Product designer. The main task was to design a black box to brew coffee by making of existing technical layouts/components (or to invent new technically and commercially viable solution).
Through very different thinking about this task I came to the conclusion that it seems like a good idea to make a device which can keep safe time and energy and space at the same time.
My Coffee Black Box consists of two devices which use the same heating system. It helps to save electric energy and time for incandesce of one heating system instead of two.

Because of the good amount of breakfasts consist of coffee and hot toasts or sandwiches I decided to join two devices in one: coffee maker and sandwich maker. Especially because of both of these devices are equipped by similar type of heating system – tubular. The electric energy consumption of these devices is equal also.
The main idea of construction is placing the tube with water close to heating element in main body of the device. The second heating element is placed in cover (on top) of device. When cover of device is closed the water is heated up by joined energy of both of heating elements. In case of sandwich cooking the heat energy is divided in this way: the water is heated up by lower heating element which also heats up a sandwich together with higher heating element (which is placed in the cover in top of device).

Also it allows solving some problems of usage like evidence of interface (functional elements) and interaction, which were discovered due to research. Therefore the form and construction of my object was created with taking into account all this problems solutions.
For example the problem with non-obviousness of containers with water and coffee is solved by highlighting this details by colour. Moreover they are placed away from main device body. Also there is used push-to-open mechanism. It allows to simplify the process of coffee beans and water reload.
The part with a sandwich maker is positioned on the top of device because of technological and fire protection requirements. The cover on the top of device has a special handle for easier opening/closing.

What do you think about this decision? Can it be estimated as a sustainable approach?