renault four – the e tree project by florian walther from germany

renault four – the e-tree* project:

renault four – the e-tree project is a full-service product package consisting of apartment units and the new renault four series. the general idea of the concept is that the costumer acquires a compound product and thereby becomes part of a process.
the further course of the text gives a detailed description of the concept regarding its core topics:

1. the car within a system
2. modularity / innovative manufacturing concept
3. innovative drive concept
4. the design

1. the car within a system:
here the multi-party apartment units and the e-tree are described.
the apartment units function as generators which enable customers of the product to produce their own energy. this “home-made energy” can be used on the one hand for everyday domestic purposes, on the other hand for charging the vehicle.
technical requirements: in order to be able to easily apply solar cell foil, the outer surface of the apartment units needs to be (mostly) clean and simple. to increase efficiency, every unit is endowed with thermoelectric converters, that work by the principles of waste-heat-recovery. another feature of the apartment block is an integrated energy storage. here any left over energy of the units is being accumulated. should a residents energy demand at some point exceed his personal supply, he can – at an additional cost which rises with the amount taken – access the storage and use some of the surplus. the additional cost is paid to the renault e-tree group. in contrast, residents who cut down on energy consumption and produce more energy than they use get an abatement of rent by renault. in order to make this approach a win-situation for renault e-tree too (“energy-savers” win due to rent abatement), the price for energy out of the storage (paid by the “energy-wasters”) is higher than the one for saved energy (paid by renault e-tree in terms of rent-abatement). the third and most important feature of the described approach however, is its educational effect on the residents with high energy consumption: since additional energy is pricy, they learn to economize with it. in order to visualize and emphasize this “conditioning system” in its social and environmental context, a symbol in form of an e-tree was created. the e-tree displays publicly every unit´s (consisting of resident and car) balance of energy and thereby supports a responsible handling of energy. since everyone´s energy balance is colour-encoded and connected to the apartment and car, an identification process with the system is ensured.

with respect to the car concept:the new renault four is an integrative component of the e-tree system because it is charged with energy produced by the apartment units. consequently its energy consumption is represented and visualized in the e-tree as well – alike the apartment units the new renault four is subject to the previously described principles of efficiency.

formula: fully renewable + less weight = less demand of energy = more efficiency

2. modularity / innovative manufacturing concept:
the new renault four follows a straight concept of modularity. that means, every element of the vehicle can be assembled, disassembled, recycled or reused by following this simple building block concept:
starting from an ultralight basic frame, elements like attachment parts and the dashboard etc. can be “clicked on” to the basic frame. by this means different versions of the new renault four, which are all based on one variable pattern, can be produced.
analogue to its predecessor, the new renault four is not only cleverly minimalistic, it moreover uses efficiently technical opportunities.
regarding the choice of materials, the new renault four makes use of “nano cellulose fiber (ncf) synthetics”, which have been developed by the renault e-tree-group-laboratories. by cultivating leafs, shells and stems from pineapples and bananas, it has been possible to produce this stronger, lighter and more sustainable material. the ncf synthetics are as strong as kevlar and are unlike traditional plastics, which are made from petroleum or natural gas, completely renewable.
to guarantee a minimal weight of the new renault four, a specific material (e.g. makrolon by bayer ag) is used, which allows to combine two component-parts into one component (e.g. integrated rear window in tailgate).
to further improve the already light and fully renewable ncf frame structure and ncf attachment parts, an innovative drive concept is used, which is explained in section 3.

3. innovative drive concept:
the new renault four is endowed with a battery-operated engine. this engine is fed on the one hand with energy from the apartment units, on the other hand with energy from car-integrated thermoelectric converters. the converters work by transforming the waste-heat of the battery and the frictional heat at the wheel suspensions and brakes into energy. due to this technique a significant increase in efficiency can be achieved. another advantage of the thermoelectric converters is their small seize and their simplicity (they don´t have any moving parts to wear out or break down).
in addition to the battery-operated engine, the new renault four features (re)chargeable body components (technique is currently developed by the imperial college london). not only do these (re)chargeable body components serve as an additional energy storage, they moreover outperform regular batteries in storage-amount and charge-velocity. potentially the car could be drawing power from its roof, its bonnet or even its doors. this makes the new renault four lighter, more compact, more energy-efficient and consequently improved in range.

4. the design:
the design of the new renault four is based on that of its predecessor without being to retro. it still matches the up-to-date-design of renault – a fresh interpretation of the original renault4 which respects its iconic features.
in accord to the modular frame concept, the underlying structure of the car becomes visible at the front and rear end (thus front and rear differ in colour from rest of car). by this means the conceptional part of the project blends with the visual part.
of course – like in the original – the front is characterized by the significant headlight which is integrated in the grill mask. the interpretation of the overall stance, line-work and proportions is also quite close to the original. especially the roof line reminds of that of its predecessor.
altogether the bodywork is kept quite simple. however, to give the new renault four a unique touch, its body is accentuated by means of graphical elements and details.
the interior follows the same principle. it is reduced to the essentials and optimized to be easily “clicked” in the frame structure ( building block criteria).

to sum up, the renault four e-tree project matches the guideline of not just being “slightly less bad”. on the contrary! the new renault four makes a real contribution to the environment. furthermore it has a positive impact on society: not only does renault with its four series follow the principles of the circular economy, moreover all customers of the product make a contribution to this sustainable system. the concept promotes their social and ecological awareness without constraining the desire for private transport and driving enjoyment. renault four – the e-tree concept is thereby perfectly in line with the renault philosophy: staying “people centered”.

*) energy-tree