Install of a largish MyEnergi Libbi battery

[nowty]

If not designed correctly buffer vessels can be a cause of inefficiency, due to extra water pumps, heat losses and the possible requirement for running the heat pump at a higher outlet temperature. [/i]

I'm certainly having a buffer tank in my system. I want to be able to run my ASHP at the most efficient times.

I think you mean a thermal store in that case.

A buffer tank tends to be a small one to specifically reduce HP cycling, whereas a thermal store is huge to store a lot of heat when its cheap rate, for use later.

[Tinbum]

Yes, sorry i do.

[Ken]

One advantage of a buffer tank must be that the HP can be run in a optimum fashion and then the heating system run in its optimum way. I have always thought this could be the best way to run a small bore pipe heating. I would have a temp in the tank to just achieve shower temp.

[nowty]

One advantage of a buffer tank must be that the HP can be run in a optimum fashion and then the heating system run in its optimum way. I have always thought this could be the best way to run a small bore pipe heating. I would have a temp in the tank to just achieve shower temp.

Buffer tanks and thermal stores are almost interchangeable in the way you use them, as I said before a buffer tank tends to be small and used to reduce cycling and a thermal store tends to be large and used to store energy. But they both perform similar functions in that they both reduce cycling and store energy. There are also different ways of connecting them.

I have zone valves which I can switch with WiFi sockets, where I can use my heatpump on Heating only, DHW tank only, or I can run both circuits together to effectively gives me a thermal store type arrangement to draw on.

Examples,
1) In winter if its very cold, and the DHW tank is low (cool), and we have entered cheapslot time, I run them both together overnight which is like running with a buffer tank and slowly warms up the tank but the temp maybe only get to mid or high 30's degrees as the heat going in with my 6kW HP balances the losses out through the radiators to the house. Then for the last 1 hour of cheapslot, the heating circuit is switched off and the DHW tank increases to around 50 degrees because there are no longer losses from the radiators.

2) Then sometimes if the DHW tank is hot and the house needs a heating boost, I run both circuits and the radiators heat up rapidly taking the heat away from the DHW tank. Of course the drawback is I'm not using the HP at the coolest temp for efficiency and I have to replace the DHW at some point.

However now I have the A2A HPs as well as my small GSHP, I generally don't need to use those examples anymore.

[Swwils]

Small bore piping will always have the limitation of how much energy you can pipe around.at both ends - you can quite easily starve even a small heat pumps exchanger with low flow.

If you are tackling low system volume you could always put a return volumiser in. If you are fightin resistance then insulation is probably the awnser.

I don't think anyone would consider a fixed output pump these days.

[Yuff]

If not designed correctly buffer vessels can be a cause of inefficiency, due to extra water pumps, heat losses and the possible requirement for running the heat pump at a higher outlet temperature. [/i]

I'm certainly having a buffer tank in my system. I want to be able to run my ASHP at the most efficient times.

I think you mean a thermal store in that case.

A buffer tank tends to be a small one to specifically reduce HP cycling, whereas a thermal store is huge to store a lot of heat when its cheap rate, for use later.

How small is small?

[nowty]

I'm certainly having a buffer tank in my system. I want to be able to run my ASHP at the most efficient times.

I think you mean a thermal store in that case.

A buffer tank tends to be a small one to specifically reduce HP cycling, whereas a thermal store is huge to store a lot of heat when its cheap rate, for use later.

How small is small?

Depends on the size of the heatpump and design of the system, but typically say 50 litres for a buffer tank and a thermal store in the 100's or even 1000's of litres.

[Tinbum]

Depends on the size of the heatpump and design of the system, but typically say 50 litres for a buffer tank and a thermal store in the 100's or even 1000's of litres.

My thermal store is 2000Lt

[nowty]

Depends on the size of the heatpump and design of the system, but typically say 50 litres for a buffer tank and a thermal store in the 100's or even 1000's of litres.

My thermal store is 2000Lt

Thats a nice 100+ kWh worth of storage.

[Yuff]

I think you mean a thermal store in that case.

A buffer tank tends to be a small one to specifically reduce HP cycling, whereas a thermal store is huge to store a lot of heat when its cheap rate, for use later.

How small is small?

Depends on the size of the heatpump and design of the system, but typically say 50 litres for a buffer tank and a thermal store in the 100's or even 1000's of litres.

The buffer tank looks bigger than our water tank, probably 200l at a guess.