SteamyTea

You may be able to get a small air to water heat pump that can suck out a few kWhs of energy at the right temperature, and if it can modulate low enough, could be used to control the overall temperature in the conservatory. It does mean that you will be having a few tonnes of outside air coming into the conservatory every day, which may have an impact on the rest of the house. I don't think there is a simple and cheap DIY method to do it. You may be better making the overhang out of PV modules or some ST panels and just use the electricity/thermal energy to heat the water in a cylinder and contribute to the ASHP running (make/buy a diverter). You will possibly find that your overall heating costs are pretty low, say less than £250/year. Water will probably be half that, so with those low levels of spend, the concept of return on investment becomes pointless (I spend more on going for a coffee each week than I do on my energy bills).

I picked up some clear drinking straws yesterday, they look the right diameter to stick the DS18B20s in, so just need to get some silicone.

As I had a couple of hours free yesterday and my 9 DS18B20s had been running a couple of days, I thought I would look at how precise the readings where. I cannot really check accuracy as I do not have a calibrated thermometer to check them against. So what I did was to create a range of temperatures that are imaginary true ones. Then look at the spread of readings in each bin range. This is pretty easy in a spreadsheet, just list a range of temperatures (I rounded down to 1 decimal point the lowest temperature then incremented up by 0.1°C). Then I looked at means between the the bin below and the bin above i.e. Temp bin below < DS18B20 reading > Temp bin above. This makes for a very quick visual comparison in a spreadsheet as the DS18B20 mean should be pretty close to the "imaginary" temperature. Some numbers are going to follow now. If I take the minimum temperatures recorded by all sensors first. 14.6°C (Imaginary), 14.72, 14.71, 14.69, 14.70, 14.75, 14.71, 14.75, 14.75, 14.70 Then the maxium 24.4°C (Imaginary), 24.50, 24.51, 24.50, 24.51, 24.51, 24.47, 24.47, 24.47, 24.52 Then the highest overall count (this gets really nerdy). Sensor 1, Count 528, Imaginary Temp 18.3, Mean Temp 18.30 Sensor 2, Count 517, Imaginary Temp 18.2, Mean Temp 18.20 Sensor 3, Count 480, Imaginary Temp 18.2, Mean Temp 18.19 Sensor 4, Count 526, Imaginary Temp 18.2, Mean Temp 18.19 Sensor 5, Count 542, Imaginary Temp 18.2, Mean Temp 18.19 Sensor 6, Count 559, Imaginary Temp 18.0, Mean Temp 18.01 Sensor 7, Count 579, Imaginary Temp 18.4, Mean Temp 18.37 Sensor 8, Count 579, Imaginary Temp 18.4, Mean Temp 18.37 Sensor 9, Count 638, Imaginary Temp 18.0, Mean Temp 18.01 So it seems that these cheap DS18B20s are pretty precise in the temperature range I have so far tested, not more than 0.15°C out, which is neither her nor there for what we are using them for. I have also not had any errors in the 11,166 readings I have taken over the last couple of days. I am sampling every 13.59 seconds overall. I also had a look at the standard error of the mean, but that is really so low that it is not worth mentioning, but I will anyway 0.03°C max. Now to really go overboard with the stats, I also looked at the median and modal values. The biggest difference from the imaginary temperature was 0.1°C on the modal values (as expected as there are not many readings, but not counted them.) The main thing here is that all the values are very close together, between -0.09 and 0.10°C over a range of 10.2° shows that the logged temperatures are pretty well normally distributed. This is a good thing when testing, as more accurate assumption can be drawn. Not sure what conclusion can be drawn from this, apart from the precision of these very cheap sensors is plenty good enough for me.

If you call a landline from a VOIP phone, what number is displayed? I ask this as I use a call blocker on my mobile, stopped my Mother calling as she had a masked number (until I unmasked it so she could call her mate).

May have to look into that as it is better than the deal I am getting. 4G works well when it is working.

I know ways to make them waterproof enough. I find a small bucket or large pickle jar quite good as the rate of cooling is slower, can then sample at a slower rate and get a more accurate result. But, as you say, in the real world it is not that important.

I go from P/Type to P/Type 1, P/Type 2, P/Type 3... Then stuff it in a box. Got my 9 sensors up and running now, shall leave them on a bit and see what they get up to. Then I can get out my 'calibration' sensor and add that to them. Then find a way to dunk them is a bucket of water without them shorting. 24/03/2017 11:22:33,27.75,27.75,27.187,27.187,27.125,27.187,27.187,28.062,27.375 24/03/2017 11:22:47,27.375,27.375,26.75,26.937,26.625,26.812,26.75,27.75,27.0 24/03/2017 11:23:00,27.0,27.0,26.375,26.625,26.25,26.5,26.375,27.437,26.687 24/03/2017 11:23:14,26.687,26.687,26.125,26.375,25.937,26.187,26.062,27.125,26.375 24/03/2017 11:23:27,26.375,26.375,25.875,26.062,25.75,25.937,25.75,26.812,26.062 24/03/2017 11:23:41,26.125,26.125,25.625,25.812,25.5,25.687,25.562,26.5,25.812 24/03/2017 11:23:56,25.812,25.812,25.312,25.5,25.187,25.375,25.25,26.187,25.5 24/03/2017 11:24:10,25.562,25.562,25.125,25.312,25.0,25.187,25.0,25.937,25.25 24/03/2017 11:24:23,25.312,25.312,24.875,25.062,24.812,24.937,24.812,25.687,25.062 24/03/2017 11:24:38,25.125,25.125,24.687,24.875,24.625,24.75,24.687,25.437,24.812 24/03/2017 11:24:51,24.875,24.875,24.5,24.687,24.437,24.5,24.5,25.25,24.625 24/03/2017 11:25:05,24.687,24.687,24.312,24.562,24.25,24.312,24.312,25.0,24.437 24/03/2017 11:25:19,24.5,24.5,24.187,24.375,24.125,24.187,24.187,24.812,24.312 24/03/2017 11:25:33,24.312,24.375,24.062,24.25,24.0,24.062,24.062,24.687,24.187 24/03/2017 11:25:46,24.187,24.187,23.937,24.062,23.937,23.937,23.937,24.687,24.0 24/03/2017 11:26:00,24.062,24.062,23.812,24.0,23.937,23.812,23.812,24.375,23.875 24/03/2017 11:26:13,23.937,23.937,23.687,23.875,23.687,23.687,23.75,24.25,23.75 24/03/2017 11:26:27,23.812,23.812,23.625,23.75,23.625,23.625,23.625,24.125,23.687 24/03/2017 11:26:40,23.75,23.75,23.562,23.687,23.562,23.5,23.562,24.0,23.562 24/03/2017 11:26:54,23.625,23.687,23.437,23.562,23.5,23.437,23.5,23.937,23.5 24/03/2017 11:27:07,23.562,23.562,23.375,23.5,23.437,23.375,23.437,23.812,23.437 24/03/2017 11:27:20,23.5,23.5,23.312,23.437,23.375,23.25,23.375,23.75,23.312 24/03/2017 11:27:34,23.437,23.437,23.312,23.375,23.312,23.25,23.312,23.687,23.25 24/03/2017 11:27:47,23.375,23.375,23.25,23.312,23.312,23.187,23.25,23.625,23.25 24/03/2017 11:28:01,23.312,23.312,23.187,23.25,23.25,23.125,23.187,23.562,23.187 24/03/2017 11:28:14,23.312,23.312,23.187,23.187,23.187,23.062,23.187,23.5,23.125 24/03/2017 11:28:28,23.25,23.25,23.125,23.187,23.187,23.062,23.125,23.437,23.062 24/03/2017 11:28:41,23.187,23.187,23.062,23.125,23.125,23.0,23.125,23.375,23.0 And just noticed that the second sensor is on the same address as the first. Bugger

You can get a letter from the DNO asking you to disconnect for a number of reasons. One is that the installer has not submitted the correct paperwork to them. It is best not to ignore those sorts of letter.

Got the soldering iron out at the moment. All seems fine now. May be different when I split them all up on different length cables, but that is for later. So a quick coding question. In Python, when you open up to read the sensors with: Sensor 4 tfile = open("/sys/bus/w1/devices/28-0316b2f96eff/w1_slave") # Read all of the text in the file. text = tfile.read() # Close the file now that the text has been read. tfile.close() After I have processed the data with: # Split the text with new lines (\n) and select the second line. secondline = text.split("\n")[1] # Split the line into words, referring to the spaces, and select the 10th word (counting from 0). temperaturedata = secondline.split(" ")[9] # The first two characters are "t=", so get rid of those and convert the temperature from a string to a number. temperature = float(temperaturedata[2:]) # Put the decimal point in the right place and display it. temperature = temperature / 1000 Can I move onto the next sensor without renaming the the tfile to say tfile1. What I have to do with the final temperature = temperature /1000 or I just keep printing out the same data. Not hard to rename them all with a simple number, just that I am lazy and wondering if it is necessary. Also reduces the chance of errors.

I am just setting up 9 sensors for calibration. Found that when I connect up 6 they are reliable, add a seventh one it goes flaky, add the eighth one and the whole lot crashes. May have to change the 47k resistor to something else (a 10k). All I do to calibrate them is to pick one sensor as a 'true' one and then plot the others against it. Then do some curve fitting in Excel, note down the equation and use that. The lag can be an issue, longer sampling times usually sorts that. They are not precision temperature sensors, but good enough for most things in a house. Terry Has T4 got a loose live wire? they can work using parasitic power, but when I tried I got a similar result, but the other way around.

In these cases where people are sent preposterous bills, is it the meter that is faulty, or something further up the chain?

Mixing in dry sand (play sand is usually dry) to the flow/top coat is a common method. As for thickness of material (the lay up), I would go for a minimum of 3 layers of 450g.m-2 (used to be called oz and a half). This should be about 3mm thick. It is easy enough to put some extra layers on the high traffic areas if you feel you need to. Most suppliers should be able to help you out with what you need. I have never layed up GRP onto OSB, so reluctant to comment. I do know that some MDFs can cause problems with delamination, as can some chip boards. The only way to find that out is to make up a sample and see how easy it falls apart. The main thing is to make sure everything is dry, and I mean really dry. Damp is the killer for polyester resins. If it goes cloudy when you first paint some resin on, stop.

Floor area is an interesting concept. Just looking at my kitchen as I type this. I have 600mm wide units, 3 in a row. Then a 50mm gap to the end of the wall by the door. Seems to me that building the walls the correct length to fit in with standard sizes can save money.

@MarkHDo you still have the plans for the cat?

At its best, I seem to remember, that it was 75%. It is only a replacement for the bathroom fan, so worked intermittently which plays havoc with efficiency numbers. I never got around to testing it properly, but from the data I did collect, there was some interesting numbers when the thing turned off and moisture condensed (well over 100% efficiency [CoP]). Still not had time to jot down my thoughts on a new design, but will try to soon.

Who is their energy supllier?

I may stray into Devon today, donate to my Kickstarter page just incase.

From scratch. Was not that hard, i wrote up about it over at the other place. Probably time to make a Mk3 version with better fans and a cheaper to make exchanger. And add some logging gear to it. Having a bit of a complicated week or two at the moment, but should be back to normal soon. Then can get working on some ideas. Maybe the electronic boys can think up a simple fan controller that can be used from a Raspberry Pi. I have some thoughts on that too.

I made mine. Still up in the loft working away. I also have some other ideas on how to make it easier and cheaper.

I shall let you know after she has popped out for a cuppa at mine

6 and a half years on, not much has changed. What you are talking about here, I think, is an active system to pump in a bit of warm air when the temperature behind the tiles is higher than the internal air (or high enough to be useful). The first thing to work out is the resource you can use i.e. the total tiled area, the amount of air that can be passed behind it (the m3/min or kg/s), the expected temperature rise from some local weather data (try weatherunderground for a station with a solar meter). As for connecting it to the MVHR, I would think that plumbing it in after the exchanger would be the way to go. It may make the balancing a bit strange, but you would be pumping in fresh heated air, so the heat exchanger may be rather redundant during those times. Think of it as a positive ventilation system.

No, but your local off licence/drug deal does

See if your local library can get hold of a copy. They get some of them down here.

How much do you want to spend, and how much time do you want to spend on it. You could buy a few temperature sensors and wire them into a Raspberry Pi. Then log the temperature differences between the input air, the output gasses, the water input and the water output. Or just use a cheap infrared thermometer to do the same thing. Keep a record of the mass of anthracite you use for each burn. Fair bit of number crunching at the end, but simple enough to set up in a spreadsheet. http://www.engineeringtoolbox.com/boiler-efficiency-d_438.html You can possibly compare the amount of losses up the birds arse with this. http://www.engineeringtoolbox.com/fuels-air-flue-gas-d_170.html And http://www.engineeringtoolbox.com/stoichiometric-combustion-d_399.html

The export limit is there to stop over voltage on local network, nothing to do with stifling innovation. If too many people had high capacity systems, too close to each other, the voltage would rise above the maximum threshold. There is then no choice but to automatically disconnect those systems. No one is a winner then.