“This temperature corresponds to 0 degrees Fahrenheit, so it was “probably a round, easy number to remember”
That’s what Allouche and team will be working on next, as they build their research summary into a full report, to be published in September 2024. “These findings give good reasons for ‘3 degrees of change’ to be further explored,” Allouche says.
Three Degrees Of Change: Frozen food in a Resilient and Sustainable Food System (PDF)
My chest freezer doesn’t even have numbers on its dial. It just goes
min - mid - max, so ¯\_(ツ)_/¯Edit: The more I think about it, the more I want to get a logging thermometer and a power meter and figure out what temperature and energy use those settings correspond to. The neat thing is, once I finish building my heatermeter I’ll actually be able to do it!
I don’t know why the dials on fridges and freezers don’t have temperatures on them. Is 7 warmer or colder than 3? Is “high” the highest temperature or the lowest? At least my new fridge has additional labels showing that 5=coldest.
Also, I looked at your project. It looks interesting, but it also looks like your project timelines resemble my own! :) I’m 15 years into my “Wall of Text” project and after numerous false starts and changed objectives, it’s current state is the welcome page saying I got the server software installed and configured.
To be clear, the heatermeter isn’t my project; I’m just assembling one. I’ve got most of it soldered; I just need to 3D-print the case, add the LEDs (which need the case for proper alignment), install the software on an SD card, and then fire it up and see if it works.
Then, for the freezer-logging idea, I’d need to figure out how to log the data it provides and correlate it with the data from one of my ESPHome-flashed Sonoff S31s. I might see if I can get Home Assistant to do it, since I want to integrate my thermometer with it anyway so it can do stuff like flash a light when it’s time for me to go outside and stoke the fire in my offset smoker.
The freezer has a far simpler ready-made solution, an Acurite or Lacrosse outdoor sensor ($10-20), an RTLSDR dongle ($10) and rtl_433 to put the data on MQTT.
I do my data logging with the free version of Mango Automation SCADA which integrates very well with MQTT and is lightweight and cross platform.
Got a sensor in each of my freezers and my root cellar, rtl_433 also picks up my weather station and rain gauge, wireless buttons, motion sensors and more, rtl_433 is a great addition to any home automation system and cheap and easy to set up.
Yes, that would be better for people who weren’t already doing what I’m doing.
Oddly enough, I’ve actually also got a RTLSDR dongle lying around. The only thing I don’t have is an outdoor temperature sensor, but instead of getting one I’ll stick with my current plan and save a weather station and/or permanent/continuous freezer monitoring for a future project.
Yup, I was suggesting it as an additional option where you can leave your heatermeter permanently installed on your smoker, and also monitor your freezer with minimal effort. Running rtl_433 is like a 5 minute project, and even an original Pi can run it with cycles to spare.
FWIW I found the best way to improve freezer energy performance is to drop your ambient temperature. This improves the COP and cuts cycle time more dramatically than changing the cold side setpoint (assuming you don’t have the freezer really cranked to near the limits of the compressor).
My freezer is in the coldest part of my house, mostly by coincidence as that’s the part nobody really lives in, with the laundry and such. It’s zoned off to mostly just be kept above freezing by passive heat.
Oops, sorry about that!
Fridges with a dial usually are an uncalibrated simple analog thermostat sensor (often a gas tube with a pressure switch) along with a simple analog control board. Fridges with a digital thermostat tend to use a calibrated sensor (usually a thermocouple) with a digital control board.
Thanks for the answer! I knew there was a reason, but didn’t expect it to be as reasonable. The only analog thermostats I’m familiar with have bimetal coils, so that’s what was in my head.