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Re: Slightly OT: Wine fridge temperature hysteresis?

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On 2017-03-06 16:56, Mike Perkins wrote:
> On 06/03/2017 16:06, Joerg wrote:
>> On 2017-03-05 18:12, Mike Perkins wrote:
>>> On 05/03/2017 19:31, Joerg wrote:
>>>> What is normal for a temperature hysteresis (or "dead band") in a wine
>>>> fridge? I am seeing 5F and more. It is a Vinotemp VT182.
>>>
>>> Most older fridges I have come across have the capillary bulb or sensor
>>> next to the cooling radiator, such that any hysteresis was reduced.
>>>
>>
>> This one is electronic. The sensor does sit next to the cooling
>> exchanger but the uC in the electronic sets the hysteresis.
>
> The hysteresis might have been set to take into account the nature of
> the cooling radiator in much the same way the mechanics of the bimetal
> sensor set the hysteresis.
>
> My point is that the hysteresis was in part negated by the position of
> the sensor, which as you say is next to the heat exchanger.
>

However, the hysteresis was still huge when I test ran it in cooling 
mode and the cycle times were very long. It just does not make sense.


>>>> Long story short I modified it to become a beer fermenting chamber and
>>>> added heating capability. Due to it being winter out here it is
>>>> operated
>>>> in heat mode right now and the original controller is still used to
>>>> measure and regulate temps. I didn't hack the micro controller part of
>>>> it (yet ...).  Currently it is set to 65F. Heat came on at 63F or 64F
>>>> and now it's topped out at 69F, still heating. Since the heater is
>>>> wimpy
>>>> that means it may be always on until it gets warmer outside. No
>>>> problem,
>>>> just got me to wonder why the hysteresis is so large on these.
>>>
>>> Not so long ago our central heating (bimetal) thermostats would have a
>>> resistor that would heat the bimetal strip when the thermostat demanded
>>> heat.  That, in a crude way, reduced the hysteresis.
>>>
>>> Look for accelerator in:
>>>    http://www.flameport.com/electric/central_heating/room_thermostat.cs4
>>>
>>
>> Crude but it works. With electronics this is no longer necessary though.
>
> Sorry, but hysteresis is hysteresis, whether through a mechanical switch
> or electronic means. I accept if you have access to the code then
> obviously you can make an equivalent of an 'accelerator heater' and save
> a component.
>

Well, for the heating situation I'd have to make an "accelerator cooler" 
and that is no small feat. Would require a peltier which dissipates to 
some other farther away part in the fridge. Plus power.

-- 
Regards, Joerg

http://www.analogconsultants.com/

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Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-05 11:31 -0800
  Re: Slightly OT: Wine fridge temperature hysteresis? Adrian Jansen <adrian@qq.vv.net> - 2017-03-06 07:46 +1000
    Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-05 14:43 -0800
      Re: Slightly OT: Wine fridge temperature hysteresis? Adrian Jansen <adrian@qq.vv.net> - 2017-03-06 11:23 +1000
        Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-06 07:48 -0800
      Re: Slightly OT: Wine fridge temperature hysteresis? dplatt@coop.radagast.org (Dave Platt) - 2017-03-06 11:41 -0800
        Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-06 12:04 -0800
  Re: Slightly OT: Wine fridge temperature hysteresis? Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-03-05 14:52 -0800
    Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-05 15:43 -0800
      Re: Slightly OT: Wine fridge temperature hysteresis? Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-03-05 16:15 -0800
        Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-06 07:49 -0800
      Re: Slightly OT: Wine fridge temperature hysteresis? "dcaster@krl.org" <dcaster@krl.org> - 2017-03-05 17:10 -0800
        Re: Slightly OT: Wine fridge temperature hysteresis? amdx <nojunk@knology.net> - 2017-03-06 06:14 -0600
          Re: Slightly OT: Wine fridge temperature hysteresis? makolber@yahoo.com - 2017-03-06 07:18 -0800
          Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-06 07:53 -0800
    Re: Slightly OT: Wine fridge temperature hysteresis? jurb6006@gmail.com - 2017-03-05 16:26 -0800
      Re: Slightly OT: Wine fridge temperature hysteresis? Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-03-05 16:42 -0800
        Re: Slightly OT: Wine fridge temperature hysteresis? jurb6006@gmail.com - 2017-03-05 20:41 -0800
  Re: Slightly OT: Wine fridge temperature hysteresis? Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-03-05 17:53 -0700
    Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-06 08:02 -0800
      Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-06 10:19 -0800
  Re: Slightly OT: Wine fridge temperature hysteresis? Mike Perkins <spam@spam.com> - 2017-03-06 02:12 +0000
    Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-06 08:06 -0800
      Re: Slightly OT: Wine fridge temperature hysteresis? Mike Perkins <spam@spam.com> - 2017-03-07 00:56 +0000
        Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-07 07:32 -0800
          Re: Slightly OT: Wine fridge temperature hysteresis? makolber@yahoo.com - 2017-03-07 10:57 -0800
            Re: Slightly OT: Wine fridge temperature hysteresis? makolber@yahoo.com - 2017-03-07 10:59 -0800
              Re: Slightly OT: Wine fridge temperature hysteresis? Joerg <news@analogconsultants.com> - 2017-03-07 11:19 -0800

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