Cool down cycle improvements

[kaffelogic]

A number of users are carrying out six, ten, or more roasts in rapid succession. Some users are experiencing a gradual build up of residual heat during such a roasting session. Others are leaving a rest period between roasts.

I am addressing this by making improvements to the cool down cycle.

The existing cool down cycle ends at a probe temperature of 40 deg C. This is often reached in under 2 mins. However, I am now thinking that a longer cooling period is needed, both for removing residual heat from the roaster, and to ensure full flavour development. So I am releasing a beta version that extends cool down to somewhere between 4 and 5 mins instead of the current approx 2 mins. The cool down now ends by detecting that the roaster has nearly come to a stable temperature.

The beta version is available for you to try at https://drive.google.com/open?id=15jC8a ... M99T-ccOit

I don't really like adding 2 minutes to the total roast cycle for the busy user who needs a coffee before rushing out to catch the bus to work, but I also don't want to add complexity. If it finds favour with beta users then everyone will get it as part of the firmware update.

[BenN]

This would be very useful.

I often wait until temp get less than 30c on display after take the beans out before next batch.
I'll definitely give it a go on next run.

[BenN]

Just tried and beans are cooled down quite good .
Previously it was still little warm on hand, but that is not the case.

I would still keep some tigress time between but roaster cooled down around 30-34C on it's display compare to 40C mark.

I can shorten the between time and better workflow if I start preparing next one after last finish it gives good time rest.

I do not might it goes constantly to 30C instead of 34C,

PS. I noticed force stop on roaster is now "Play" and then "Minus" button instead of double push of "Play". I needed bit of time to figured it as so used to double push the play button, but that also prevent accidental stop. So I think it;'s a good improvement.

[Justine]

This extra cool down works for me. I can still easily separate the screen to free the trapped beans, but without it being too hot to handle.

[Damian]

I can’t get to 40 C on hot days.
How will this effect the log graph, 30+ % of the x axis is going to be cool down?

[kaffelogic]

I can’t get to 40 C on hot days.

The design of the Nano 7 limits how much cooling can take place. The air entering the roast chamber has already been used to cool the power supply for the fan motor, and is warmer than ambient by typically 8 to 10 deg C. If you are prepared to wait more than 5 minutes you can cool to ambient plus 8 deg, at the four minute mark you will normally be at around ambient plus 10. To cool to 40 deg C you must be in a room at 32 deg C or lower. At room temperatures of 28 deg it will still take a long time to get down to 40.

If you roast in temperatures of 35 deg C or more, you will not be able to cool lower than 45 deg C.

The current beta version extended cooldown is looking for the rate of rise to flatten off as a way to know that it is approaching the cooling limit and determine when to end the cooldown. This is why you will notice it stopping at different temperatures.

How will this effect the log graph, 30+ % of the x axis is going to be cool down?

Good point - I have made a note that the standard view will need to truncate the cooldown part of the graph.

[Damian]

Maybe a zoomable x-axis would be possible?
Or split the current zoom in to separate Y zoom and X zoom controls

[kaffelogic]

I have updated the beta release that has the cooldown cycle improvements.

The old cool down cycle is still in the current release 7.3.12

The latest beta is now numbered 7.4.3 and includes the improved cooldown cycle and improved ambient temperature calculation. This has been engineered to support continual back-to-back roasts throughout the day, adapting to changes in ambient temperature through the day and completely draining all residual heat between roasts. It's hard for me to be sure how it will perform in all environments (temperature, barometric air pressure, and humidity) so your feed back on how it performs will be much appreciated.

https://drive.google.com/drive/folders/ ... sp=sharing

[Noob]

Hi Chris, I've just gone to download this and see there's a 7.4.4 there too. Should I use that or stick to 7.4.3 per your post?

[kaffelogic]

see https://kaffelogic.com/community/viewto ... t=143#p898