SteamyTea

Well it will be 16A ~3.7 kW But that is governed by total module size, not inverter trickery (usually, there are always exceptions). So decide what you can do with an extra 2 kW as an off grid system i.e. dedicated water heating/sewage plant running/battery storage.

Split it into 3 sections and fit 3 separate 4kW inverters. Then switch of the inverters you don't need. Actually you may want to fit 3 3kW inverters to get better efficiency.

kW k for thousand. W for watt.

Not the numbers, it is the units.

Always worries me when I see things like this Heat Coil 30 kw And then a second time Output: 30 kw

I have worked for people that like to make a simple job difficult too.

Could have been worse. Could have dreamt about Sisyphus.

So very little floor losses then.

@PeterStarck What U-Value is your floor. That makes a difference to the losses from UFH. Also the overall size of the building is important. Area to volume ratios make a difference, ask anyone with a small house.

A 1 kW load will need a 1.5mm2 cable, at 80m length, the volt drop will be 4.4% (10.1V) A 2 kW load will need 4mm2 cable, at 80m length, the volt drop will be 3.3% (7.7V) (this is not strictly accurate as I used the TLC calculator which assumes it is for fixed in place wiring) A quick look on eBay and I found this: https://www.amazon.co.uk/Lengths-H07RN-F-Rubber-HO7RN-F-Outdoor-Black/dp/B075ZFLLTG/ref=sr_1_5 About the same as a cheap generator.

I wonder if your controller lets you know the CoP. Maybe have a look next time I am over. Trouble is, playing with the buttons can inadvertently set something wrong.

Size is partly down to the volume of air that needs to be moved. Location is generally in opposite corners, away from doors and windows. The main problem is that air does not store much energy (1 kJ/kg.K), so to heat or cool 1 m3 of air, which has a mass of ~1.2 kg, you need to use 1.2 kJ of energy, plus the energy to move it, but that is very small in the scheme of things. This page can be used to calculate how much power and at what flow rates are needed. https://www.engineeringtoolbox.com/water-flow-rates-heating-systems-d_659.html You just need to substitute the specific heat capacity of water (4.2 kJ/kg) for air (1 kJ/kg), and the density of water (1000kg/m3) for air (1.2kg/m2).

I was being a bit facetious. I may have to see if I can get another script that logs more interesting data. Using the phone as an internet enabled hotspot could be useful though as the range is quite good. It could be set up to activate a switch that opens up gates and doors, or just turn lights on. Flattens the phones batteries quick though.

So accessed websites and passwords then, to a government department.

It is really just an electrical problem. The higher the current, the larger the switching needed. Solar Thermal is an interesting problem. It does, on the face of it, seem simple and reliable, and the efficiencies seem higher. This is a bit of simplistic view of it as it does not take into account the times the system cannot function i.e. not enough light, system already up to temperature, not enough temperature difference to transfer energy. This is where PV starts winning. As long as the modules are producing enough voltage, the inverter can convert that to AC at at known voltage and resistance. That can then be put into the store of water, or anything else that needs current. Ideally you need to be able to store energy, water and stone i.e. storage heaters, are pretty good at this as they don't take a lot of looking after, resistance heating is very reliable, not pumps, antifreeze, sludge removal, leaks etc. Storing a small amount in batteries is also useful as it is unlikely that a PV system will always be producing enough kW (power) to run a kettle (about 2.8 kW), but it can keep a 1 or 2 kWh (energy) battery charged that can power a kettle (as it only needs a fraction of a kWh to boil a litre of water (~1.1 kWh). The real problem is that in the summer you need a small system, in the winter a large one. Why small windturbines can be useful. A 1 kW windturbine will probably consistently produce about 200 W, but for 24 hours a day (this is all weather dependant of course), but that is 4.8 kWh, which is about the energy my house uses in total on a non washing day (clothes not my body).

DC requires larger switches. And if low voltage, larger cabling. AC is really the way to go as the kit is easily available. And what happens if, for some reason, you get a current flowing through water between the heating element and the cylinder?

I am a bit wary of these broadband monitoring services. It is a great way to collect data on people.

I don't think you should have the modules flush with the tiles as they need some air movement underneath for cooling. When I went to @Jeremy Harris's place I never noticed the PV at first.

Did a bit of poking around the interweb and found this script. It is better. It gives a 1 or a 0 depending on if it is connected or not, and the number of seconds it is connected, as well as a timestamp. #!/bin/bash TIMESTAMP=`date +%s` while [ 1 ] do nc -z -w 5 8.8.8.8 53 >/dev/null 2>&1 online=$? TIME=`date +%s` if [ $online -eq 0 ]; then echo "`date +%Y-%m-%d_%H:%M:%S_%Z` 1 $(($TIME-$TIMESTAMP))" | tee -a connection.csv else echo "`date +%Y-%m-%d_%H:%M:%S_%Z` 0 $(($TIME-$TIMESTAMP))" | tee -a connection.csv fi TIMESTAMP=$TIME sleep 60 done;

I tend to agree that direct resistance heating heating is cheap to install and maintain. But for a new build, and better control, it is hard to beat an ASHP these days. Too true. 60% of the time my house uses nothing. worked out with our Ed Davies a while back that my fridge uses 5W, maybe double that in the summer when it gets very hot in the kitchen (actually down here that does not happen hardly at all) Yes. Did anyone run the numbers if the 600mm was under the floor and 300mm in the loft?

I did not know about that. Feel free to modify and improve my code. It would be quite good to see if it is possible to make something decent, but extremely lightweight. I did think of putting the info you get when you ping an address into a text file, but never got around to it. I just dumped the landline.

Can you make a copy and put in your router IP address. Run the two together and see what comes out. Will need to change the .csv file name.

I think most of the Code for Sustainable Homes got dropped. Was a London centric load of nonsense.

That is odd, shall see if I can get it running here, it should show when I take the phone away. May take me a while to set up a spare RPi.

Good, will be interesting to see how it works on your system. The only problem is that it does not actually say where the problem is. I am sure a clever person could modify it to find out. Maybe ping the router and google, that may pick up a router or PC connection problem.