Legionella, tech stuff and stepping out

It is deep into our second winter in Portugal.  We saw the tail end of last year's winter but got to experience a cold house with no hot water when we moved in so I felt we needed to be well prepared this time around.

I described our engine room and the solar heating for our water - at the time I mistakenly referred to the water heating array as photovoltaic when in fact it is an evacuated tube solar collector. 

The difference being that these vacuum tubes heat fluid that is passed over a small, hyper-heated metal tip at the top of each rather than by producing electricity that can be used to power a hot water element.

My concern as I tried to get familiar with the three pumps and how the water in our large water tank is heated was eased over the summer when the solar array had no trouble keeping our hot water at around 45ºC (113F) which was more than adequate for showers.

As we moved into fall I had a few different contractors come over to look at the water heating system to see how it could be improved.  I has bothered me that we have to light a fire in the kitchen stove to heat the water especially in the spring and fall when we are not getting enough heat from the solar tubes to keep the showers hot though it is not cool enough to need a fire burning in the kitchen.  

Anne and I have been so jaded from all of our previous months of travel that we have been reluctant to move around much and it took a forced trip to Lisbon to get South African passports renewed for Nick and me.  It got us to think about moving around a little more.  I had booked tickets soon after we arrived to see Jacob Collier in November in Lisbon and had an appointment to handle some administrative tasks for my residency permit in December. 

Jacob Collier concert

This forced us to travel to Lisbon a few times, with the added need to spend at least one night in Lisbon each time.  So we started to look into low-key places to visit while we there.

It turns out that going to Lisbon distance-wise is much like driving up to the White Mountains from our home in Boston (2hrs) or driving to Port Elizabeth from Grahamstown (ok, maybe a bit further than that) - two typical journeys that we were willing to make reasonably often when we lived there. 

Banksy museum

Because Portugal is so small these trips feel huge but we put on our American attitude about distances where we'd have no problem going from Boston to New York for a weekend (5-6 hours drive) so why hesitate to go to Lisbon?

We loved some of the parks and museums in Lisbon and now feel less intimidated about walking in the city or visiting to watch some culture when it  comes up.

And why not visit Seville for that matter?  One of Anne's best friends from our days in Grahamstown was visiting her sister in Madrid and we drove to Seville to meet her and spend time catching up the day after New Year's day.  

 Cindy is a fellow artist and has a son a little younger than the boys are.  It was great to visit the grand cathedral in Seville with her and to go out for a meal on the river before she had to return on the high-speed train to make her flight back home.

Returning from Seville put the heating situation back into focus.  Because the system we have is complicated, I could see the visiting plumber/heating person's brain shutting down when they saw it all and I would wait for the inevitable: "I don't really understand this system so I think you should install (a) a new electric boiler, (b) a heat pump or (c) photovoltaic cells to heat water on the roof".  

I guess I understand how this works - people don't want to take on something that is complicated and may end up costing them a lot of time, but it bothers me that the prices for these alternative systems are high and I'd rather find out how we can mitigate the specific problem in the short term and then hear a plan for how to improve it over time instead of just fork-lifting it all out and replacing it.

The hot water tank is enclosed in a room made out of insulated iron cladding and the tank itself has a large insulated cover on it.  The person who did our pre-inspection for the sale of the house said that the hot water tank can be fitted with an electrical element so I'm planning to open the room up and see if I can find where this fitting is and then get a plumber to just install the element and a thermostat.  If that works we can start to talk to him about upgrades along the lines that he prefers.  Anne is not enjoying how the air in the house deteriorates when we add wood to the fire so we will probably aim to switch that stove out in favor of something that will be less problematic with her asthma.

I mentioned in my previous post that Rob and Eurika visited from Melbourne. He described his sophisticated heating system and septic handling.  He does have a heat pump and is able to set things up so that he uses batteries during prime time and then get the solar array to work charging the batteries and providing electricity for the rest of the time.  Their septic system is amazing too,  designed to produce water for irrigation with all of their grey water and the outcome of processing the sewage being cycled back into watering the plants.  

I read about this and don't see that the septic arrangement is possible for us because you need a pretty large area for a septic system like this.  The solar electricity is feasible.  Portugal is almost 80% on renewable energy so our electricity is not very expensive but it would be nice to lower the need for electricity from the grid where we can.

I have become a little less tolerant of running the tank at 45ºC after the conversation about legionella with Rob so I’ve been working to keep the tank water on or above 55C which has meant more frequently having to light the fire even if it is warm out.

So now, in the dead of winter I have been stuck with a daily routing: come down in the morning to check that the fire still has glowing embers, get it burning again and then go outside to check the various temperatures (top of tank, stove generated heat, solar tube temperature) - I usually check the temperatures a few times during the day.  The under-floor heating and showers drain the heat from the tank, so we have leave the under the floor pump off if the tank temperature isn't higher than 55ºC.  

It's a pain having to make this trip outside a few times a day (and then again at night just before we go upstairs to get ready for bed).   If it is raining for a few days in succession as it has been for the last couple of weeks it becomes even more of a pain.

I remembered that a friend who managed a training/recreational retreat on an island with a lighthouse in Maine had given me a link to his notes on how he set up monitors for equipment and temperatures and controlled some of the electronics.  I dug it up in an email from a few years ago for some of the details - in particular the type of temperature sensor and how to store the data coming from them in a way that can be used to graph it.

This would be ideal, because being able to see what the temperature trends are over the course of a few days could help me decide when to turn on the pump for the underfloor heat and also to see how much heat is actually coming from the solar tubes (I had more or less decided that they are not doing much at all).

I paid about €18 for a small IoT (internet of things) device from Shelly to which you can attach an ad-on that will allow up to 5 temperature sensors (costing about €18 as well). 

The small red and black Shelly with add on

A bonus was that the Shelly device is intended for measuring electrical usage and has an electronic switch in it.  That tiny box has 2 wifi radios and is about the size of a regular matchbox so it is easy to install in an electrical encasing.  The 2 wifi radios allow you to use one of them for initial configuration and the other to connect to the home wifi so that it can push data to whatever you have set up to receive it.

It was a bit strange dusting off some of the  software tools that I used at work.  We used software that a colleague installed to graph test-bed performance. I installed it here to measure internet speeds and my internet router performance and so I was able to pull together the bits that I need to start graphing the water heating system as well.

I discovered that the heat from the solar tubes is not insignificant.  It looks like I should get a larger array.  It circulates fluid into the hot water tank close to the bottom of the tank where the temperatures are a bit lower and you can see in the screenshot of the graph below the yellow lines show how it has varied over the past week of mostly raining days and then again was doing better yesterday and today when the sun came out for a few hours.

The blue graph shows when the underfloor heating is on and the green graph is the temperature of the fluid returning to the tank from the floor.  It goes up to just under 30ºC - I usually turn it on in the morning and sometimes leave it on all day depending on how comfortable we are at home.

The Shelly control panel with the electronic switch

By Boston standards it is mild here but with the outside temperatures between 2ºC and 14ºC we find that our home is toasty with the woodstove going and the underfloor heating on.  Without the underfloor heating we have to use traditional heating from fans blowing over heated elements and so it is a much more comfortable heat if it comes from a warm floor.  

Not to mention that Anne loves to not wear shoes whenever possible.

Anne posing at our new gate with her Scatterlings of Africa design