I have been introduced on the internet to Simonelli's Aurellia II, group 3 machine, and I am left breathless over beauty of that thing. That was in the morning. By lunch time I have made a decision to move all furniture out from my living room to make space for it. I am thinking that I can have breakfast on the first group, lunch on the second, and now you get drift where this is going.

P.I.D. is making really splash, having potential to grow into really something big. By the end of decade I expect flow meter will be added to inform you on water profile, and recommend grinder setting to get best out of the bean in your hopper, yet somehow I think Elektra from sixties will retain its customer base, just as iPad group probably will marry this baby or alike. Any thoughts?

In Nuova Simonelli's words... http://nuovasimonelliusa.com/aurelia.html

THE NUOVA SIMONELLI AURELIA IS AN ENGINEERING MARVEL AND IS THE ONLY ESPRESSO MACHINE DESIGNED USING COMPUTED THEORETICAL MODELS TO AVCHIEVE TEMPERATURE STABILITY. IN ORDER TO ACHIEVE ITS HIGH LEVEL OF TEMPERATURE STABILITY, EVERY ASPECT OF THE MACHINE HAD TO BE PERFECTLY BALANCED AND ENGINEERED TO EXACTING STANDARDS. THE RESULT IA AN AMAZING AND TRULY REMARKABLE SYSTEM THAT SELF-STABILIZES USING ITS OWN WATER AND A SINGLE HEAT SOURCE TO MAINTAIN THERMAL EQUILIBRIUM. THE AURELIA'S SCIENTIFICALLY DESIGNED BREW GROUP WEIGHS OVER 12 POUNDS AND IS A KEY FACTOR IN THE MACHINE'S TEMPERATURE STABILITY, AND IT ALLOWS THE OPERATOR TO CUSTOMIZE THE DEGREE OF PRE-INFUSION, BREW TEMPERATURE, AND FLOW RATE INDIVIDUALLY.

Sakae wrote:P.I.D. is making really splash, having potential to grow into really something big. By the end of decade I expect flow meter will be added to inform you on water profile...

To me, this is the next exciting area for exploration. With gear driven pumps and an accurate flowmeter connnected to a PID, one could really produce consistent pressure profiles that are not only pressure driven but flow driven (which may be more valuable). I expect to see this technology sprouting up soon. I plan on adding pressure profiling to my Linea once Eric gets it working but the flowmeter part of the equation is still a ways off, and perhaps not possible for me with my current equipment.

The Aurelia has been around for five years, and is the machine currently used for WBC championships. Its thermal stability is based on its inherent thermodynamic properties, and would be the same whether it were using a PID or a conventional pstat.

PID is a classical control algorithm suitable for analog r/c circuits or pneumatic controls. In mathematical terms, it became obsolete with the development of state space controls in the 1950s, in terms of circuit design, it became obsolete with the introduction of cheap microprocessors in 1970s, which are much easier to program using state space concepts than with with PID algorithms. Their continued use in the current generation of microcontrollers makes about as much sense as using a touchscreen abacus on an ipad.

The reason they still exist is the same as why Qwerty keyboards still exist, and why there's bound to be some sort of touch screen abacus app somewhere: people do not change nearly as fast as technology.

I confused Jim, and I know you know your stuff when it comes to PID's. To me, they are a big step up from t-stats that used to be in my machine. Tighter temp monitoring and controlled responses to fluctuations are a big benefit to PID. Did I misunderstand your response?

THE RESULT IA AN AMAZING AND TRULY REMARKABLE SYSTEM THAT SELF-STABILIZES USING ITS OWN WATER AND A SINGLE HEAT SOURCE TO MAINTAIN THERMAL EQUILIBRIUM.

A thermosyphon and hx?
Am I missing something, plumbing looks like most hx out there.

It it becoming transparent that I should be looking for more than just an On/Off switch.

mitch236 wrote:I confused Jim, and I know you know your stuff when it comes to PID's. To me, they are a big step up from t-stats that used to be in my machine. Tighter temp monitoring and controlled responses to fluctuations are a big benefit to PID. Did I misunderstand your response?

If you put a PID controller on, say a Silvia, it will still drop 2C from beginning to end of shot, since it has a small boiler and there is nothing the PID can do about it. Put a PID on a system with an exposed group, and the initial temps will be slightly off, due to environmental changes. Put a PID on a one ton rock, and it won't do anything at all.

The Aurelia is the thermal equivalent of a one ton rock, with huge capacitance. To change the shot temperature, and engineer comes and changes the jets, the sizing of the heat exchanger and the valving on the thermosyphon, oh and yeah, changes the PID for the boiler temp a degree or two. On an old school machine like this, the capacitance is huge, and temperature fluctuations in the boiler created by the Pstats deadband do not matter.

The Aurelia is the best walk up machine I've ever used: no flush, no muss, silky preinfuse, any reasonable technique works to get a really good shot. But it is the swan song of old school design, with everything massive and stable. Newer machines, with in-shot pressure and temperature profiling, will need to be light, very unstable, and use high speed controls: basically twitchy little thermoblocks with risc processors built in. For a machine like this the PID algorithm would be useless, rather you need something that monitors ambient air and incoming water temperatures, the rate of flow, and calculates the required heat, then uses feedback only to tweak the settings.

For a machine like this the PID algorithm would be useless, rather you need something that monitors ambient air and incoming water temperatures, the rate of flow, and calculates the required heat, then uses feedback only to tweak the settings.

Sounds like modern automotive engine control. Something I can wrap my head around. This thread has been a great read. Keep the tech coming, guys.

-Peter

Yeah, except it scares me a lot more in cars than it would in an espresso machine.