Month: January 2023

I have noticed that my water appears to run hotter in the morning when I get up vs later on in the day. In truth this is probably due to relative temperature where in the morning I am colder and so things appear warmed but I still wanted to find out how much my water temperature changed throughout the day if at all.

Looking at the temperature profile throughout the day I saw some interesting spikes that occurred like clockwork at 5am. Breaking this into minitab and looking at the temperature intervals vs hour we find that there is indeed a statistically significant difference in the morning at 5-6am vs later on.

The cause is most likely that I have my heating turn on at this time and this is likely heating up the water in the pipes leading to this rise in temperature and thus leading some credence to my theory that the water is warmer in the morning. Of note the temperature sensor is on the outside of the pipe so potentially I am seeing the warm air heat up the sensor rather than the actual water but I used thermal compound to make good contact with the pipe and it is copper after all so thermal conductivity should be good.

6 months ago I came along the desire to understand what my incoming water temperature is and how it varies over the day. As a part of this I have mounted a temperature sensor to the outside of my incoming mains water pipe and found some interesting results. Now though I understand that I am not measuring the actual internal water temperature being that this is a copper pipe I am getting a fairly close approximation.

A big result of this was my post https://adam-s.ca/data-analytics-and-finding-out-when-you-shower/ in which I investigated my ability to find when I shower based on water temperature. This is a quintessential process engineering/controls engineering problem where my desired measurable is unable to be measure and so I have to measure a separate variable that is “joined” to my required measurable and go based off that. Granted, in a big company you can buy a sensor for anything given you have the money but this is a good example for the process control on a budget.

I had an interesting theory mid year in 2022. The though being that you should be able to theoretically find out when you shower based on measuring the temperature of the water mains line (talk about shower thought).

The theory is simple, if the incoming water temperature is not at the ambient temperature (ambient being not real ambient but rather the temperature between the wall and concrete of the house), then you can tell if there is a change in flow rate by a change in temperature. This is based on the fact that if there is no flow, the water pipe temperature will reach equilibrium with the environmental temperature and any flow from this point will lead to a change in temperature.

I strapped a temperature probe to the outside of my water mains over the last 6 months to better understand this and have found very compelling results. In fact the latest trails today proved out my exact theory.

In the chart below you can see a few different stages over the morning. The first is when my heating comes on in the morning to heat up the house when I wake up (temperature set point is set to 21.5C in the morning so I wake up to a warmer house). I then started to shower at about 6:50am which resulted in an almost immediate drop in incoming water temperature leading credence to my theory. Once I finished my shower the water temperature began to stabilize again and I notice another suspected shower event where the water temperature shot down again once again leading to my theory of being able to identify showers based on water temperature.

The big learning lesson from this is that you may not always be able to measure your desired measurable but in any process there are always a lot of intertwined variables. Here we may not be able to measure direct water usage but we can measure changes in water temperature with the assumption that these are coming from large volumetric flow rates.