Not sure if this is a popular use case or not but I wanted to get some ideas.
I have setup PV diversion to trigger my ASHP. When this happens it has an energy meter to limit the amount of electricity it can use (to the amount of PV being generated).
I would like to know if it is possible to have an additional setting in the heatpump app to show if the unit has been triggered by the smart grid relay or if it is running because it has to (similar to how we see DHW/ space heating usage)
The main reason for this odd request is that while overheating/ buffering to DHW / space heating will obviously be slightly less efficient due to it heating to higher temperatures, this would be during peak solar so most likely warmest part of the day.
I would like to figure out if there is a noticeable impact on SCOP using this Vs pure weather compensation.
Anyone have any ideas how to implement this or would this need to be an ER (not sure it deserves much attention due to the niche use case).
Could you create a bunch of virtual feeds that showed electrical and heat power without the periods triggered by the grid smart relay? Assuming this signal is a binary 0 or 1, then these simply multiply the original feed by the smart signal. Once you have this, you can set up a second instance of the My Heatpump see if the overall COP is any different.
I also have a similar setup with my Eddi set up to either use the immersion when there is a small amount of excess solar or to trigger the heat pump via the Smart Grid inputs to heat the water when a threshold of excess solar is reached.
When triggered this way the heat pump is operating less efficiently as often the tank is not as cold as when a normal cycle is triggered and it is set to go to a higher temperature. This is still more efficient than direct electric immersion but does cause the COP to take a major hit.
This is what I am trying to figure out with my setup. I have both DHW and Space heating as options for buffering so hopefully by playing with some virtual feeds I can work out the impact of using PV diversion Vs not.
The thing to remember is that by using the buffering you are reducing overloading on the grid during peak supply from solar and then also reducing demand during peak supply times as the house and water are already hot enough, so while COP will play a part it depends if your goal is Purley efficiency or if you are trying to be a bit more eco friendly/green as with buffering you don’t need to use your battery for heating in the evenings/ can also feed excess back to the grid.
Yes the reasons for doing it is to try and use excess solar as its normally more expensive to buy back but to do this in the most efficient way (heat pump rather than immersion).
Also my excess solar is least useful to the grid when the sun is shining so if I can use it then to not need it later in the evening even better.
So I’m willing to accept the hit to COP it would just be good to be able to remove these runs as it makes it harder to compare how well my setup is to other systems for normal operation.
