GSHP - I need help with making it as efficient as possible!

countryhouse39

Sorry didn't respond sooner been very busy with work. Thanks for all the comments, will look into adjusting some of the settings like the set back. We actually had an engineer out this week to repair a fault on a manifold, and have asked him about what we can do to make it more efficient. He seemed to think that reducing the flow temp by a few degrees wont make that much difference to the cost, and is going to look into what else we might be able to do (examples he gave were ensuring the pipes are insulated etc). one thing that might be worth noting is that the pipe runs are quite long, with the layout of the house meaning that it is a long way from the pump room to our bedroom. 

Reed_Richards

countryhouse39 said:

markin said:

The night set back of 15c seems far to low to me, they have to work very hard to get back up and underfloor heating makes it far worse as they can take 6+ hrs to days to get back up to temp, i think 18c would be far better.

ok - thanks - will see how we go raising this slightly.

If you have half decent insulation it will make no difference whatsoever.

matelodave

It's reckoned that 1 degree on the flow temp can add 2.5% to the running cost, so if you can reduce the temp by say four degrees you could have a potential saving of around 10%.

Ideally back off the flow temp until you are cold or it takes too long to reheat the place and then just increase it by 1 degree every couple of days until its just right. Leave the system to settle for a couple of days between tweaks so you can gauge the effect. Lowering the flow temp increases the efficiency and lowers the running costs, even it the unit has to run a bit longer as it's not working so hard.

Think of it a bit like driving a car, you get better fuel economy at 50mph than you do at eighty even though it takes a bit longer to get to your destination.

Hexane

matelodave said:

Think of it a bit like driving a car, you get better fuel economy at 50mph than you do at eighty even though it takes a bit longer to get to your destination.

On this point you're better off looking at it differently!

Imagine that every time you want to accelerate from 40mph to 70mph, you put your foot flat to the floor, and accelerate as fast as you can. (My car makes a pleasant roaring noise.) That's less efficient.

Imagine that instead, when you want to accelerate from 40mph to 70mph, you keep the car around 2000rpm to 3000rpm the whole way... less roaring noise, and more efficient. YMMV.

countryhouse39

So, thanks to your replies I’ve been doing various things to try to get a handle on our usage - and just got an energy monitor that monitors the usage of JUST the heat pump as we have a meter for just the pump so can see how much of our usage is down to that rather than other electrical usage. I only plugged it in yesterday, so the overall usage isn’t the thing I’ve noticed so far, however I’m kind of surprised by the level of base usage it’s reading as when we aren’t calling for heat at the moment (the pump is on so can come on for the hot water etc but isn’t ‘pumping’ at the moment) and it’s reading 945w?! Surely this is high? Or am I being daft? See attached picture of monitor. Or is it that the pump IS on and doing something important it’s just not noisy? 

Reed_Richards

I assume the display shows the amount of heat generated rather than the amount of electricity used. If you took the picture at 10 am and your heat pump had generated 12.118 kWh today then either something is getting a lot of heat (swimming pool?) or the monitor is not reading correctly.

QrizB

countryhouse39 said:

... I’m kind of surprised by the level of base usage it’s reading as when we aren’t calling for heat at the moment (the pump is on so can come on for the hot water etc but isn’t ‘pumping’ at the moment) and it’s reading 945w?! Surely this is high?

Seems high to me, too, as does the 12kWh for the day (assuming your heating is off and the HP is only providing hot water).

Some heat pumps have a built-in heater to keep the compressor warm; is yours one of those, and if so can the heater safely be disabled?

countryhouse39

It’s the top reading I’m worried about at the moment, not the 12kwh total (which I will worry about later!) as that’s a total since I plugged it in - about 2pm yesterday. 

It’s a monitor that is reading the meter in the pump room - it’s reading the red flashing light on the meter? I don’t know that the meter in the pump room is measuring the electricity used, but I had assumed it was rather than what is generated but I can check. No swimming pool!! 

1961Nick

countryhouse39 said:

So, thanks to your replies I’ve been doing various things to try to get a handle on our usage - and just got an energy monitor that monitors the usage of JUST the heat pump as we have a meter for just the pump so can see how much of our usage is down to that rather than other electrical usage. I only plugged it in yesterday, so the overall usage isn’t the thing I’ve noticed so far, however I’m kind of surprised by the level of base usage it’s reading as when we aren’t calling for heat at the moment (the pump is on so can come on for the hot water etc but isn’t ‘pumping’ at the moment) and it’s reading 945w?! Surely this is high? Or am I being daft? See attached picture of monitor. Or is it that the pump IS on and doing something important it’s just not noisy? 

12kWh with a COP of 2.5 for DHW over a 20 hour period isn't unreasonable. If the heating operated during that period it's even better.

We used 23kWh of gas yesterday (DHW only).

QrizB

countryhouse39 said:

It’s the top reading I’m worried about at the moment, not the 12kwh total (which I will worry about later!) as that’s a total since I plugged it in - about 2pm yesterday.

OK, it says "today" so I assumed it's since midnight (the monitor should have a clock that you can set so it knows when days begin and end).

It’s a monitor that is reading the meter in the pump room - it’s reading the red flashing light on the meter? I don’t know that the meter in the pump room is measuring the electricity used

It sounds like you are measuring the electricity used, not the heat generated. A heat meter is a completely different piece of kit.