OpenEnergyMonitor Community

Heat pump monitoring documentation

I’ve added a new page in the applications section of the OpenEnergyMonitor guide on heat pump monitoring:

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:
This page also links to a useful blog by @johncantor with mounting suggestions for pipes

Extended pulse counting documentation to cover wired pulse counting:

and added documentation to cover the MBUS EmonHub interfacer to be used with the USB to MBUS reader:

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:

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:

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

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

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:

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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.

I found the emonub part of it here but that sort of demonstrates the disjointed nature of the documentation…

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?


One of these and a couple of wires
/ crimps

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!

Documentation updated @borpin

This is on the emonhub interfacers page:

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.

Open source schematic and board files available here :slight_smile: :

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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