Dynamic Heat Pump Simulator

[TrystanLea]

The latest version of our dynamic heat pump simulator now supports:

• Time of use tariffs!
• Fixed speed compressor mode (surprisingly useful!)
• Weather comp with parallel shift
• Standby and pumping power consumption
• Feature to save and compare current simulation with previous base line simulation

Available: openenergymonitor.org/tools:

Dynamic heat pump simulator

[TrystanLea]

Electrification of Heat optimisation example

I’ve been using this tool over the last week to simulate what the effect of improving control settings could be on some of the Electrification of Heat systems, e.g this period for EOH2578: Emoncms - app view.

Here’s the real data:

and here’s the simulated version:

Tuning the weather compensation and running the heat pump all day could improve the COP and reduce running costs by 20%:

This heat pump is a bit over-sized hence continued cycling even at minimum modulation.

We might be able to save 10p with a bit of a setback (using auto adapt control mode here rather than fixed speed):

Cosy costs would be similar with this simple setback schedule but deliver savings with over-heating during cheaper periods, e.g almost a £1 saving here vs continuous mode (18%) or a £2.31 saving (34%) vs the initial poorly optimised weather comp base line.

Thoughts very welcome!

It’s possible to explore all sorts of things with this!

[ectoplasmosis]

This is great, and very helpful for explaining how heat pumps work best to heat-pump-curious but gas-boiler-indoctrinated users who can’t wrap their heads around best-practice methods.

Would it be possible to add custom ToU tariff pricing to this tool, and to the broader heatpumpmonitor platform? Or at least add the Tomato Lifestyle tariffs, which are very popular with heat pump owners without EVs/solar etc.

[TrystanLea]

Thanks @ectoplasmosis !

@ectoplasmosis

Would it be possible to add custom ToU tariff pricing to this tool,

Yes it’s possible to enter custom ToU tariffs, it’s tariff pricing and timing is fully editable. There an option to load cosy as an example but you can change everything from there..

[ectoplasmosis]

Great, thanks! Can this custom tariff comparison also be done when viewing monitored installations via heatpumpmonitor.org?

[TrystanLea]

@ectoplasmosis

Can this custom tariff comparison also be done when viewing monitored installations via heatpumpmonitor.org?

HeatpumpMonitor.org needs pre-set tariffs, as tariff cost processing is done as a background process over-night. The best thing there would be to add these further tariffs to that calculation process.

[ectoplasmosis]

Understood. Would it be possible to add the Tomato Lifestyle tariff, with 01:00-06:00 @ 5p/kWh period, 09:30-11:30 and 20:30-22:30 @ 14p/kWh, and 23p/kWh at all other times?

[TrystanLea]

Yes sure, Il make a note of that, it might be a few days

[langestefan (Stefan de Lange)]

It’s very cool! Well done! To be able to instantly test a new scenario is quite valuable.

I said this before but it would be nice to have an MPC controller so you can make use of what you learned about the building. Not easy to implement though!

Speaking of, how are you determining the building fabric parameters? It doesn’t say explicitly but I assume these are the thermal masses and resistances in between?

[TrystanLea]

Thanks Stefan

@langestefan

I said this before but it would be nice to have an MPC controller so you can make use of what you learned about the building. Not easy to implement though!

Definitely interested in this, While the PID works to a degree, it’s not producing exactly what we see on real world heat pumps, so I’d like to get to something better.

@langestefan

Speaking of, how are you determining the building fabric parameters? It doesn’t say explicitly but I assume these are the thermal masses and resistances in between?

Yes just on simple 3 stage RC model on the building side of things dynamic/docs/dynamicmodel.md at master · emoncms/dynamic · GitHub

Even this simplicity can give great reproduction:

[langestefan (Stefan de Lange)]

Thanks! I am mostly curious if you have come across any good method to identify the thermal parameters of a building. All the data to do so automatically should be present in heat pump monitor.

Second point and quite important is how to determine the initial conditions. What temperatures do the masses have when you start the simulaiton? In my own simulations I found that increasing the temperature of any significant thermal mass, mainly the envelope, will have a dramatic effect on the results. You will also see this in your own data: a day at -5 C preceded by a string of cold days will require more heating than a day at -5 C preceded by a string of mild days.

[TrystanLea]

@langestefan

if you have come across any good method to identify the thermal parameters of a building. All the data to do so automatically should be present in heat pump monitor.

Not yet, agreed that would be nice! What I would like is the ability to drop an Emoncms MyHeatpump dashboard link into the simulator tool and for the tool to then automatically tune the model based on that data. Maybe something for the future.

@langestefan

Second point and quite important is how to determine the initial conditions. What temperatures do the masses have when you start the simulaiton?

Agreed, when you open the simulator it runs the simulation over 20 days (at 30s interval), the final result is based on the average over the last 4 days. This seems to be enough to remove the sensitivity to those initial starting conditions.

[TrystanLea]

@langestefan

You will also see this in your own data: a day at -5 C preceded by a string of cold days will require more heating than a day at -5 C preceded by a string of mild days.

Agreed, whenever a change to conditions is made in the simulator, a further 3x 4 day = 12 days total are simulated. Even this can not be quite enough and that’s why there is a “refine” button, just to make it possible to run the same conditions for another 12 days per hit.

[martin53 (Martin Roach)]

My own experience with tariffs (referred to in other posts) shows that smooth running of my heat pump, on a constant price tariff (benefitting HP, not rest of house) compared with a time of use (benefitting all usage during certain hours) leads to:

1. No significant hange in cop
2. Significantly lower heat required per degree difference to meet target temperature - presumably linked to less need to make up for heat loss during high/medium price periods
3. Therefore less electricity used for space heating for same temperature difference
4. Plus more capacity to meet heating demand at very low outside temperatures, though yet to be tested at coldest (-3deg C) on constant price tariff. Data are available down to near zero degrees outside temperature.
5. Resulting in significantly lower whole house cost of electricity for all temperature differences above delta T=7, which covers most autumn and winter days and more than makes up for lower cost of TOU tariff in summer/shoulder months
6. Savings over previous modern gas boiler at all temperature differences for space/water heating.
7. My conclusion is that while cop is an important consideration as test of design/set up of system, choosing the right tariff, and in my case benefit of constant running, is key factor in whole house (space and water heating plus all other appliances) cost of energy and capacity for meeting space heating demand at lowest outside temperatures.
8. Note that my system does not have battery capacity and only limited solar (the latter may benefit constant tariff costs in summer when other appliances are running on higher priced kWh). The system was optimised for each tariff during each running period. True test would be full year comparison for each tariff but this was not possible given 2024 installation of heat pump and desired to quickly identify lowest cost tariff.