Completely new to this forum and it seems far too technical for me .. but looking for some help please? We have recently installed 2 Ecodan cascade Air source heat pumps - and I am trying to work out my consumption (which I think is a requirement of the BUS installation grant). The device and MelCloud are “unable” to monitor usage apparently because it is a cascade system. I have been pointed to this forum for possible suggestions on how I could measure usage? Is there a device I can buy /install that can help me?
Welcome, @Carpemterstation to theOEM forum
Are you likely to be interested in knowing the operating details of your heat pumps and optimising their performance at some time in the future, or - as things here seem too technical - do you just want a local record of your heat pump’s electricity consumption overall? It’s something I’d suggest you think about before you spend money.
But before we go into details - is the information you need available on-line via the Mitsubishi MELCloud App?
Simply answering your requirement “how I could measure [total] usage?” - You buy an emonPi2 with one current transformer and an emonVs combined power supply and voltage monitor.
To install it, you’ll need to get access to the single ‘line’ wire (the brown one) either before it comes out of your consumer unit or somewhere else on its way to the heat pump(s) to fit the current transformer, and you’ll need a standard 13 A socket nearby to plug in the emonVs.
If you want to monitor both heat pumps with one c.t., both wires need to go through the one c.t. To monitor each heat pump separately, then you need to add a second current transformer, and then each needs to be on the wire feeding their respective heat pump. Clearly, there are practical questions about where and how how you might be able to do this, and a lot more information is going to be needed before I can go into details.
And you’ll want a usable Wi-Fi signal where your emonPi will be located. If you can’t get this, you’ll need to uprate the Raspberry Pi inside your emonPi to a RPi 4B and use a wired Ethernet connection to your router, in order to see the graphs etc.
So your potential shopping list is:
1 - EmonPi2 + Raspberry Pi Zero 2W + EmonVs with UK plug, no expansion board, one 50 A c.t.
I’d need to know the Model number of each heat pump to confirm the c.t. rating, but the price difference between one or two c.t’s and different ratings isn’t massive.
If you’re not comfortable going inside your consumer unit or inside your heat pump, then you need to add in the price of a local electrician to fit the c.t(s) and possibly install a socket for the emonVs.
It might or might not concern you - if you have the emonPi2, all your consumption information is under your control (and your responsibility - so back it up if it’s important to you) and immediately available. On-line, it might be minutes or hours old, or it might suddenly be charged for or stop, or historical data might disappear. Similar things have happened in the past.
Don’t hesitate to come back with any questions.
MelCloud does not support cascade systems. I get no energy usage at all from MelCloud. I can get overall usage from solar apps and smart meters but no measure of efficiency… (other than “it’s warm enough” and I know how much energy I am using!)
I want to optimise our set up. That is a bit difficult without having a COP measure to refer to. So I think I need to be able to track actual energy usage and actual heat generated.
I can tinker with flow temperatures, flow rates and weather compensation curves to try and keep the compressors running at a sensible level using thermostats and rad valves as limiters rather than controllers.
Wired or wireless internet connections are not a problem. Getting 2 c.t’s Around the brown wires will be the hardest parts.
Our units are Mitsubishi Ecodan 8.5kw units (2 of them)
I got the impression from your initial post that all you wanted was the electrical consumption. However, it now sounds very much as if you actually need a Heat Pump Monitor so that you can also have a measure of the heat generated. Have you seen this: Cascading / multiple heat pump setting ?
Although The Shop website makes it very clear that the forum here is the primary source of support, in fact the price you pay for the heat pump monitor includes support direct from The Shop, so I really think that while others here, like @Timbones who’s just started to type something, can tell you about their systems, the actual configuration will need to involve Glyn & Trystan.
Welcome to the forum!
I can think of the main options:
1- it’s possible to extract the data out of MelCloud, and estimate usage from that. I have no idea how this works with cascades, but would be happy to look into it for you. Charting flow temperatures would be useful if nothing else. Send me a private message, and I’ll explain the setup.
2- there are devices you can plug in to the heatpump to extract that same info. Again, I don’t know how this works with cascades, and may be more technical. Have a look at Monitoring & Controlling Ecodan via CN105
3- buy and install (or ask a plumber to) the heat pump monitor kit that a Robert mentions above. This will give the highest quality data and analysis, and doesn’t rely on Mitsubishi support.
For more general advice on cascades, this topic may be useful: https://community.openenergymonitor.org/t/converting-ecodan-systems-to-cascade/
Click your Icon (‘C’ in the lt brown circle top right), click the envelope twice, then New Message. Start typing the user “Timbones” in the obvious place.
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Users have bought 3 connectors of mine before, one for the master FTC and one for each slave FTCs
This way you can get individual, computed input and output power per unit
Then in home assistant you can do totals
Im not sure you can extract everything you need to estimate power with MELCloud connected to Master only (and probably why cascade doesn’t give energy data on the main controller)
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