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#1 |
Apprentice EcoRenovator
Join Date: May 2011
Location: Tortosa, Spain
Posts: 221
Thanks: 2
Thanked 81 Times in 46 Posts
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![]() I may have posted about this before but anyway this is an update and it's now working...
It is now cool at night so time to run the heatpump which is connected to the under floor heating in my house. The daytime temperatures here are still hitting 26C so the heating is only really needed at night. I had my hp set to heat the water to 32C which gives us a nice comfortable environment but, during the day, it gets too warm in the house so it's a bit of a waste. I was resorting to reducing the temperature manually. So it seemed sensible to use a weather feed and automatically set the temperature for the heating. I had used openweathermap.org for a feed previously but their feed data for 5 day, 3 hour (which is what I wanted) was too big for my ESP8266 to process. I had written some code to handle parsing in chunks but the feed sometimes changed and this broke the parsing code. They seem to have updated their API now and you can select a certain number of reports. As I only wanted 3 reports this now makes it possible to process the feed with the memory constraints of the ESP8266. So I have finally implemented my automatic temperature setting based on the feed data. I may need to modify some of the values but the basic functionality is now there. The Water Temperature Set value is the average of the Now Temp and the Temp in 3 hours. |
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#2 |
Lurking Renovator
Join Date: Jan 2020
Location: Romania
Posts: 13
Thanks: 0
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![]() Well done for what you have accomplished . Do you use a diy heat pump or is a factory made one ?
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#3 |
Apprentice EcoRenovator
Join Date: May 2011
Location: Tortosa, Spain
Posts: 221
Thanks: 2
Thanked 81 Times in 46 Posts
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![]() It's all diy - the controller and installation anyway. The heatpump itself is a basic compressor/fan/reversing valve unit that I have added my own controller and control software to.
I describe it all in this post https://ecorenovator.org/forum/showthread.php?t=5017 although the software has been upgraded several times since then. Currently I'm updating the thermostat that goes with the heatpump and have created an app for my phone so I can control the heating directly. The flame on the right is animated to show when the compressor is running, the bar on the left is to increase/decrease the set temperature. |
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#4 |
Lurking Renovator
Join Date: Jan 2020
Location: Romania
Posts: 13
Thanks: 0
Thanked 0 Times in 0 Posts
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![]() Looks very nice , well done to you !
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#5 |
Apprentice EcoRenovator
Join Date: May 2011
Location: Tortosa, Spain
Posts: 221
Thanks: 2
Thanked 81 Times in 46 Posts
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![]() I've updated my heatpump controller code a little to include nighttime reduction (which is configurable) so the heating temperature reduces overnight.
I've now had the predictive weather code running a few weeks and after a few minor temperature tweaks (I'm sure more will follow) it is working really well. |
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#6 |
Apprentice EcoRenovator
Join Date: May 2011
Location: Tortosa, Spain
Posts: 221
Thanks: 2
Thanked 81 Times in 46 Posts
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![]() When I added the predictive weather code and had it running it wasn't windy.
Where I live it can be very windy and the last few days it has been both windy and cold. I was surprised what a difference it made, the set temperature based on the temperature alone wasn't enough to keep the house warm (enough). My house is pretty well insulated so this shouldn't really occur - but it did. I guess the main losses are from the windows (double glazed but you still notice the cold when you are close to them) and there are quite a few. So I added in another factor into the algorithm, the wind chill factor which fortunately is calculated to a 'feels_like' parameter in the openweathermap api. Adding this factor in raised the temperature and all was well once more :-) I had to add a few more setting points in the code as I had only catered for temperatures to -5C, and with the wind chill this could be lower so now I have to -10C. |
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#7 |
FNG
Join Date: Jul 2015
Location: Washington
Posts: 71
Thanks: 8
Thanked 19 Times in 13 Posts
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![]() Cool stuff!
It's neat to see how other people tackle a problem. I like your addition of the evaporator and compressor temps. I've been doing something similar for a few years using the NOAA.gov weather forecast feed. I searched thinking I had added it here to the forum, but I guess I just mentioned it in my last post in my heat-pump thread and never updated the thread with more detail: https://ecorenovator.org/forum/showthread.php?p=47976 The URL I posted at the end of that thread will give you XML data for the latitude and longitude you plug in. I wrote some Python that runs on a Raspberry Pi to grab the XML for the next 168 hours (seven days), then parse the XML. They give you wind and precipitation data too, so I plot that in python. From the NOAA temperature forecast, I fit a 5th order polynomial curve. Then, I take the first derivative to get the rate of temperature change. Those two polynomials are used to generate hourly points for a "response" curve in a CSV file. It's kind of like solving a differential equation and plotting one point for each hour. I let that script run every night at midnight. The automatic mode pulls up that CSV file every hour and changes the temperature to the value calculated by the "response" curve. The result is a All of that is presented on a little web page running on the Raspberry Pi. I just pass parameters through the URL to change settings. I've attached a screen shot of the interface. |
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The Following User Says Thank You to TechShop For This Useful Post: | jeff5may (07-06-21) |
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#8 |
Lurking Renovator
Join Date: Jan 2020
Location: Romania
Posts: 13
Thanks: 0
Thanked 0 Times in 0 Posts
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