machine 303

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So far, energy consumption has not been an important criterion when choosing an espresso machine. However, the public perception of the topic of "energy" has been changing for some time due to the climate debate, so it made sense for us to think in this direction in the second half of 2019. In addition, over the years we have built up a stable production of the Xenia, which allows us to research the implementation of interesting and sustainable ideas. With all the possibilities and knowledge that we have acquired about the production of espresso machines, we want to set about building a machine with two boilers and an exposed brew group that is very energy-efficient in every respect.

However, energy savings alone would probably not be enough to bring a machine into production and successfully onto the market, because the costs will not be insignificant. And so it is planned that this machine will have a number of features that are associated with high-end machines these days. This includes access via WLAN and the option of individually adjusting reference parameters such as boiler pressure and temperature.
There are also some practical additional solutions that can be implemented more easily in a completely new design.

Energy Saving

It can be assumed that with an espresso machine a lot of energy is lost via the brewing group. Exposed brewing groups are very popular with buyers, but lose even more energy than the groups of so-called balcony machines - which, however, are not widely accepted in the home for design reasons.

For this reason, we opted for an exposed brew group for this machine. However, we are also sure that even with exposed brew groups, it is possible to contain the release of heat into the environment very effectively. The construction is therefore quite different from the usual. Usually, brew groups are a solid component made of (mostly) brass. The new brew group of the 303, on the other hand, has a multi-part construction: on the outside there is a shell, underneath there is an insulating layer and on the inside there is a core: this is then the actual group and is to be made of copper. Stainless steel would be possible, but we rejected it because the comparatively low thermal conductivity of stainless steel is rather counterproductive for espresso machines.

What you see as a brew group is a type of hood that installs separately from the actual group (the core) and has an insulating layer towards the core.
The core is screwed into the horizontal operating unit via 4 screws and brought into the correct position via spacers.

A positive side effect of this solution: the cover does not get as warm as a conventional exposed group and is also a good protection against contact for children and curious visitors.

The group is heated by 2 heating cartridges that extend almost over the entire length, and these heating cartridges must be precisely regulated by the control unit (in the manner of a PID controller with power regulator).
The second major source of energy loss is boilers.

Thus, in this machine, the two boilers are completely sheathed (on the sides at the top and bottom), which effectively prevents heat loss. The insulation is only interrupted in a few places for supply and discharge lines. The construction can be seen in the picture on the right.

We are currently planning a large boiler for steam and a smaller boiler for brewing. The brewing boiler is equipped with a special heating system that makes it possible to heat the incoming cold water inside the heating system before it enters the boiler. This way we increase the temperature consistency.

Each boiler is installed on a support that is also insulated towards the boiler to avoid thermal bridges as much as possible.

Ideally, this would be based on the principle of thermos flasks, but that would be too complicated for the application. We are talking about a so-called aerogel as a very good alternative.

This describes how the core idea of saving energy is essentially implemented—apart from details (such as insulating pipes that carry hot water).

A note on the 2 boilers: We consider the dual boiler to be overqualified for home use, but the use of 2 boilers (of different sizes) seems to make more sense under the heading of 'energy saving'. This is explained in more detail below.


Heating Time

The heating time is always an important issue. Since the boiler and brew group are separate and controlled separately, it should once again be possible to reduce the heating time compared to many other machines. In any case, this relatively large machine (approx. 38 cm wide, 37 cm deep and 31 cm high) must be ready for use noticeably under 10 minutes.


The current status

If you are interessted in our ambitious project you can read here more:

https://www.xenia-espresso.de/en/?mgi_3 ... schine-303

and (in German):

https://www.kaffee-netz.de/threads/projekt-303.129126/

The machine is close to the production and we started to order the 1st parts for the 1st small batch. A few minor changes are needed and in a few days we know the final price.