Heat pump monitoring documentation

Organisation Documentation
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I’ve added a new page in the applications section of the OpenEnergyMonitor guide on heat pump monitoring: Heat Pump Monitoring - Guide | OpenEnergyMonitor

It covers 3 levels of monitoring:

  1. Electricity monitoring using an EmonTx or EmonPi
  2. Monitoring system temperatures using an EmonTx or EmonPi
  3. Heat metering, either via pulse counting or via a USB to MBUS reader plugged into a emonPi/emonBase that we will soon be stocking in the shop.

To cover these three topics, I’ve added a page on adding temperature sensors to an emonPi/emonTx:
+ Add Temperature Sensors - Guide | OpenEnergyMonitor
This page also links to a useful blog by @johncantor with mounting suggestions for pipes https://heatpumps.co.uk/2015/06/08/temperature-sensing-with-openenergymonitor/

Extended pulse counting documentation to cover wired pulse counting:
+ Add Pulse Counting - Guide | OpenEnergyMonitor

and added documentation to cover the MBUS EmonHub interfacer to be used with the USB to MBUS reader: EmonHub Interfacers - Guide | OpenEnergyMonitor

The EmonHub interfacer documentation also covers interfacing with an SDM120-Modbus single phase electricity meter that is Measuring Instruments Directive (MID) approved. Im using this on the electric feed to my heat pump so that I have both MID metering on the electric supply and heat output of my heat pump: EmonHub Interfacers - Guide | OpenEnergyMonitor

The heat pump monitoring application page also links to our heat pump monitor through-hole kit development board, that combines many of these feature in one unit, however it’s probably easier for many users to use an EmonTx/EmonPi configuration with either pulse counting for reading from the heat meter or the soon to be available MBUS reader. We have a limited number of these through-hole boards left and we’ve reduced the price for these in the shop. The intention is to replace this initially with the USB to MBUS reader connected to the emonPi/emonBase and potentially a simple WiFi MBUS reader later. An MBUS reader will also be available on the STM32 hardware.

I still need to add a section on the emoncms heatpump dashboard and link @MyForest’s app here: Heat Pump Experimentation App - Release News

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Overall I’m getting great results with this setup on my 5kW EcoDan air source heat pump here. Here’s a screenshot of the emoncms heatpump dashboard showing its performance over the last 30 days:

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clicking on a day it’s possible to see a more detailed graph of electricity input and heat output alongside flow and return temperatures:

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Using the Octopus Agile app its possible to see the cost of the heat pump in isolation of the rest of the house:

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I’ve been really pleased with the results, e.g an average COP of 4.4 over the last 30 days and unit cost for electricity of 11.8 p/kWh means that the unit cost for heat is 2.68 p/kWh which works out at ~30% cheaper than mains gas if you include the additional standing charge and boiler efficiency.

I put together a video about the heat pump system for a CarbonCoop webinar a couple of months back if anyone is interested in the details of the heat pump installation and house :slight_smile: A mid terrace heat pump example (COP: 3.92) - YouTube

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Great to see @TrystanLea - keep up the good work.

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Would be good to include direct pulse counting using a PiZero and the pulse interfacer as well.

[edit]
I found the emonub part of it here emonHub Interfacers — OpenEnergyMonitor 0.0.1 documentation but that sort of demonstrates the disjointed nature of the documentation…

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Thanks @MyForest

@borpin we could add a section to that page detailing the direct approach? I was going to ask you if you had a good picture of your setup showing the connection to the Pi and attached pulse counter?

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@TrystanLea

One of these https://www.amazon.co.uk/gp/product/B07YY611M9/ and a couple of wires
/ crimps

2020-11-25 12.58.27
2020-11-25 12.58.274096×2304 1.85 MB

I think if it was long term I’d cut the end off the Sensor and add a connector directly onto it.

pulse_pin = 15
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Thanks @borpin that’s tidy!

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Documentation updated @borpin

This is on the emonhub interfacers page:

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and mentioned from the pulse counting page:

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We now have the through-hole version of the MBUS to UART reader available in the shop, designed for use with the EmonHub MBUS interfacer, Im pre-assembling the first batch of these as we will be switching to a SMT design in due course.
https://shop.openenergymonitor.com/mbus-to-uart

Open source schematic and board files available here :slight_smile: :
https://github.com/openenergymonitor/HeatpumpMonitor/tree/master/Hardware/WiFi_MBUS_Reader/v1_TH

The shop item is for the MBUS to UART configuration of the board (designed for use with an emonPi or emonBase) and does not include the optional ESP8266 WiFi components. I haven’t finished the software for that configuration yet.

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It might be worth adding a link to this from the pulse sensor shop page. This is the cheapest way to setup energy monitoring (IMHO).

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