Disabling Weather Comp during mid winter?

[JohnMo]

4 hours ago, andyj007 said:

it uses 10-14 kw of power

 

Think it's supposed to say "it uses 10-14kWh of energy."

[andyj007]

15 hours ago, ReedRichards said:

 

You get up to 14 kW out of what is nominally a 10 kW heat pump?

sorry my bad not enough coffee,, yes thats correct at about 0-3 degress and intake is about 14kwh   over that period    the 10kw pump maxes out full chat and rquires 3 kw -3.2kw  for the 5hour stint. 

 

Edited December 9, 2023 by andyj007

[IGP]

It sounds like a use case for the Homely controls to optimise.

[Pip895]

I am looking to do this with our system.  I intend to run flat out for 6 hrs overnight at 7.5p/kWh (Intelligent Octopus Go) then if the house really needs more during the day It will probably be via a gas boiler at the moment, with gas at 5p/kWh a heat pump running on electricity at 30p/kWh just cant compete!

[JohnMo]

30 minutes ago, Pip895 said:

I am looking to do this with our system.  I intend to run flat out for 6 hrs overnight at 7.5p/kWh (Intelligent Octopus Go) then if the house really needs more during the day It will probably be via a gas boiler at the moment, with gas at 5p/kWh a heat pump running on electricity at 30p/kWh just cant compete!

Mine did this fine until it starts to get colder.  The problem I found with this plan was the amount of defrosts the heat pump did, but great until you hit about 3 or 4 degrees and lower. Have reverted to 24/7 low and slow with hardly any defrosts, last night between -1 and 4 degrees and did only 3 defrosts.

[Pip895]

1 hour ago, JohnMo said:

Mine did this fine until it starts to get colder.  The problem I found with this plan was the amount of defrosts the heat pump did, but great until you hit about 3 or 4 degrees and lower. Have reverted to 24/7 low and slow with hardly any defrosts, last night between -1 and 4 degrees and did only 3 defrosts.

I will need to calculate it but even with defrosts I think the heat pump will win over gas - once we go down below about -1 we will be on gas though. How do you control it all?  Can you do it within the Heat pump programmer? I was intending getting my OH to program a Raspberry Pi or something.

[JohnMo]

12 minutes ago, Pip895 said:

Can you do it within the Heat pump programmer

Some do it, some don't. Found the instructions are generally way more complex than they need to be. With way to many options that are not easy to plumb in or understand h way to easy to get wrong.

 

Could be made really simple with a relay, this would be seamless (ish) - down to temperature say 2 deg, you have permission for heat pump to run, the relay switching at the preset temperature would make gas boiler come online and switch off the heat pump. Heat pumps normally have a remote on/off contact that could be used, the boiler has a call for heat contacts. You would need a few check valves to make sure the flow directions are correct and you don't get back flow through boiler or HP.

 

[ReedRichards]

I like the room where I sleep to be a bit cooler at night.  I suppose I could manage that using a smart TRV on the radiator in the bedroom whilst making the rest of the house really hot on cheap night-rate electricity.  Did nobody following this type of strategy have any comfort issues?  

[JohnMo]

9 hours ago, ReedRichards said:

I like the room where I sleep to be a bit cooler at night.  I suppose I could manage that using a smart TRV on the radiator in the bedroom whilst making the rest of the house really hot on cheap night-rate electricity.  Did nobody following this type of strategy have any comfort issues?  

You can only really do it with thick screed and use it as a storage heater. Over charge the floor you are hot all day, under charge you are cold all day. It's a fine balance to get it right. You need to stop heat input earlier than you think as well

[andyj007]

its working well for us.  i .  i also have a log burner that is plumbed in to heat hot water or under floor.. everything is auto matic ..  if we fire up the log burning it switches off the het pump  once it reaches 50 degree flow temp out  log boiler, (assuming we have ashp pump on and thermostats alling for heat..  ..  a local company throws way sawdust briquetts , we bur these.. log burner gives 2kw to room and 7 kw to water..  i dont really need t heat the bathrooms just a hour or so every couple of days to keep floor so its nit ice cold.. in these rooms we use infr red heaters,, flick em on 5mins before you go for shower and turn off when you leave.. makes room super toastie and cost way ess than heating the floor to heat the room ..   

there are many other  tricks you can do when deigning a new house , that allways gets just missed..  

 

 

 

[JohnMo]

33 minutes ago, andyj007 said:

its working well for us.  i .  i also have a log burner that is plumbed in to heat hot water or under floor.. everything is auto matic ..  if we fire up the log burning it switches off the het pump  once it reaches 50 degree flow temp out  log boiler, (assuming we have ashp pump on and thermostats alling for heat..  ..  a local company throws way sawdust briquetts , we bur these.. log burner gives 2kw to room and 7 kw to water..  i dont really need t heat the bathrooms just a hour or so every couple of days to keep floor so its nit ice cold.. in these rooms we use infr red heaters,, flick em on 5mins before you go for shower and turn off when you leave.. makes room super toastie and cost way ess than heating the floor to heat the room ..   

there are many other  tricks you can do when deigning a new house , that allways gets just missed..  

 

 

 

Interesting.

 

[dpmiller]

we're doing the E7 ASHP/ boiler stove combo too, and this year I'm trialing using the immersion diverter towards the end of the E7 period to get some extra heat in the TS without troubling the heat pump with excessive defrosts. I've also increased the room temp a degree to charge the screed a bit more.

 

Stove isn't fired every evening but when it is, 3-4 hours makes for a cozy room to watch telly in  and adds about 15c to the TS

[SteamyTea]

8 hours ago, dpmiller said:

Stove isn't fired every evening but when it is, 3-4 hours makes for a cozy room to watch telly in  and adds about 15c to the TS

How cosy.

Having grown up in the tropics, I still find 24°C a 'bit chilly'.  Humans evolved in places with a mean temperature of 26°C.

26°C I find quite nice, but still need long trousers and my jumper on.

Edited December 17, 2023 by SteamyTea

[ReedRichards]

4 hours ago, SteamyTea said:

Humans evolved in places with a mean temperature of 26°C.

 

But I doubt that they evolved wearing clothes.  Clothes are what should enable you to feel comfortable at lower temperatures.

[Ronny]

On 07/12/2023 at 11:51, ProDave said:

My gripe is there is not an off peak tariff available that does not in some way penalise you for at least some of the "normal" usage times.

 

And in part my resistance to having a smart meter.  There really is this thing that late afternoon / early evening electricity is expensive, but being all electric I do not want to be forced into a position where I either have to cook and eat outside a time I consider "normal" or pay through the nose for the privilege.   People keep pedalling the  notion that smart meters are for the consumers benefit, where the reality it is for the grids benefit to try and even out demand through time of use charging, i.e force behaviour change, cook your dinner at some other time being just one of them.

 

I also have solar PV so have a natural desire to use as much in the daytime, so do as much of my heating then, heating at night counters that so seems to conflict with having solar PV.

 

So on balance at the moment I will just stick with a single rate tariff on a dumb meter.  Appreciate other views differ.

I am on Octopus cosy with the high charge from 16.00 till 19.00. I also have solar and batteries and i make sure they are fully charged to see me through the expensive period. 16.00 and the heat pump is off and i have an air con in the living room which runs till 19.00. In my monthly bill i normally use a max of £1.50 at the expensive rate. The capital outlay for this is of course very high. I also have no gas as i had it taken out just after the heat pump was installed so i did not have two standing charges to pay. There is no tariff available as far as i know which is suitable for a heat pump, lets hope the tariffs eventually get back to close to normal. My panels are 8 east facing and 8 west facing and generate very little at this time of the year, so no help there.

[ReedRichards]

5 hours ago, Ronny said:

There is no tariff available as far as i know which is suitable for a heat pump

I've never worked out why Octopus think "Octopus Cosy" is suitable for a heat pump.  Presumably you think it is vaguely suitable, @Ronny?  

[HughF]

Completely unsuitable for us…. The thing just runs 24/7 at the moment on weather comp…

[JohnMo]

1 hour ago, ReedRichards said:

I've never worked out why Octopus think "Octopus Cosy" is suitable for a heat pump. 

 

Should be called Octopus 'battery' really, that's the only real use I see with it, having an ASHP is just a bonus.

[Ronny]

15 hours ago, ReedRichards said:

I've never worked out why Octopus think "Octopus Cosy" is suitable for a heat pump.  Presumably you think it is vaguely suitable, @Ronny?  

It is only suitable if you have batteries to carry you through the expensive times. The advantage is having "cheap" power in the afternoon as well as during the night. Lets face it there is no "good" tariffs available from any supplier as far as i can see.

[Ronny]

14 hours ago, JohnMo said:

 

Should be called Octopus 'battery' really, that's the only real use I see with it, having an ASHP is just a bonus.

You are correct.

[JohnMo]

I am just running E7 and it's currently averaging out 30% cheaper than normal rate on a 24hr basis. Have an ASHP and battery.

[HughF]

5 hours ago, Ronny said:

It is only suitable if you have batteries to carry you through the expensive times. The advantage is having "cheap" power in the afternoon as well as during the night. Lets face it there is no "good" tariffs available from any supplier as far as i can see.

Octopus tracker seems the best option out there, from what I can see.

[Ronny]

20 hours ago, HughF said:

Octopus tracker seems the best option out there, from what I can see.

I have had a good look at the various tariff`s from octopus and it is very difficult to compare. My December bill was for 838.7KWh at an average price of 18.65 pence per KWh. I would need to find a tariff less than this to make a saving. What makes it impossible, i am looking for a big saving not a small one !!!!!. Unfortunately when we bought this house and were renovating it i did not recognise the back and front are covered by roof tiles (cape dutch style) and this means there is no insulation on the back and front of the first floor. To rectify that now i would need to remove all the plasterboard to insulate and still leave an air gap. Doing that would probably save more money than looking for tariff savings. 

[SteamyTea]

2 minutes ago, Ronny said:

What makes it impossible, i am looking for a big saving not a small one

That is the problem with swapping 'deals'. The savings are generally so small that they are not worth the bother.

[andyj007]

Some of thsoe Octopus tarriffs  i struggle to make sense of ,, and gave up trying to get on their flex ine ...  out of all of them we found british gas to be the most simple for us.. just works ,     just a straight .09p form 12-5 am 30p all other times , half price  15p on sundays.. export 15p kwh   no fancy ev  meters just use what you want..  when we need to import we  buy 95% of electric requirements    at .09p or 15p  , this to charge our house batteries  our bmw i3 ev car, and charge our floors with heat  floors via ashp..     Only needed that Nov-dec. jan feb on consec cold days below 6 degree  .. PV  & batts covers all other months     we run our enture  4000 sq ft house, energy /heat and our i3 ev car for less than £100 per year all in total..  and hoping to get that a new zero or negative cost through 2024 - 

Edited December 28, 2023 by andyj007