Coming to a smart meter near you...

[Tim+]

What do you think your thermostat does? It turns it on and off regularly.

Tim

[Steve Walker]

Many (most?) fridges and freezers these days are electronically controlled and the power to the electronics is not normally switched on and off. I would not expect a problem doing so, but there is probably some slight risk of repeated cycling increasing the failure rate.

[Theo]

We're not talking a relay in the power rails here. The microcontroller that controls the fridge just has another input from the Zigbee module to say 'please don't chill now'. The controller is free to ignore that input if the temperature is out of the safe zone.

If you're designing a failsafe fridge (ie not an Argos special) you could make the overtemp detection a hard analogue circuit. But TBH a microcontroller with a watchdog timer is probably just as reliable than a circuit whose values could drift with temperature, age, etc.

Compressors cycle many times a day and last for decades. In the past they had a mechanical thermostat and lifetime was just fine. Delaying the start time makes them run for fractionally longer, but so does somebody opening the door.

It's an enormous non-problem.

Theo

[newshound]

Common in the London suburbs in the 1950's.

[T i m]

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I am in the process of converting a de-humidifier to a 'smart'(ish) one with an ESP module and some extra bits.

It's currently switched on / off via Home Assistant (thanks to you <g>) using a ZigBee (Lidl) mains switched socket and a Sonoff / Zigbee Temp and Humidity sensor nearby.

If you watch the log / graph of humidity you see it climbing when the de-humidifier is off overnight and then falling again when it's on during the day (10:30-00:00). Except when the tank is full and it cuts off or if / when it freezes up and has to defrost etc.

So, as I've already constructed an ESP32 based remote (WiFi) sensor that gives me temperature and humidity and is currently also driving a relay (that could switch the de-humidifier on / off), all I now need is to tap into the three indicators (On, Tank Full and Defrost) and I would also be able to see what it's doing when I'm not there. ;-)

I've also fitted the ZigBee controller to the kitchen lights, driven by a PIR in the ceiling and along with similar in the hall and landing, it's cool to be able to walk though the house and have the lights follow you. ;-)

I also have another ESP32 'watching' my electricity meter and giving me a 'live' reading of energy used and so I could potentially manage my overall load to avoid the idea of being disconnected, should it ever come to that.

Cheers, T i m

[The Natural Philosopher]

I lived in the london suburbs in the 1950s. I never saw such

First power cut I remember is the 1970s miners strike

[charles]

They were not unknow inEdinburgh in the 1940s/50s. Storms from the NE would cause sea water to get into the power ststion's switchgear. The trams all stopped. My father had a paraffin lamp hanging on the kitchen wall - being prepared.

[Scion]

When looking for a new fridge/freezer about 5 years ago I was tempted by the Samsung range but totally put off by many purchasers' comments that the electronically-set thermostat did not remember its programmed value after even a short power cut, and without a programmed value the appliance did not work. One commenter came back from holiday to find all his frozen food defrosted/spoiled after a power cut that lasted a few seconds.

[tim...]

and you'd need to either rewire the house with separate circuits, which seems nonsensically expensive

or have a house full of smart appliances, which is entirely at the whim of the customer

[tim...]

except that manufacturers would see the addition of this item as a means to add more smart functionality that they can sell to the user at an uber premium price

The idea that this feature will be added at cost is for the birds

[tim...]

I've owned storage radiators that haven't come on "today" because the time switch didn't notice the "on" time signal that it was sent

This isn't implemented via a fool-proof protocol

[tim...]

consumer resistance