Heat Pumps: anyone have one/thought about it?

[jonneymendoza]

How are you going to charge the batteries off grid?

Using the solar panels?

I wouldn't just get solar panels... I would also get batteries and even a air con so in the hight of summer I could cool down my rooms for almost for free lol.

Its like heat pumps. I would not get just a heat pump. I'd get a hot water cylinder because as far as I know, heat pumps don't offer on demand hot water, correct me if I'm wrong though

 

[Mercenary Keyboard Warrior]

Using the solar panels?

I wouldn't just get solar panels... I would also get batteries and even a air con so in the hight of summer I could cool down my rooms for almost for free lol

Right so yes we are back to hows that going to work.

Solar in the UK is highly seasonal in regards generation.

To have an array thats going to guarantee a useable amount in deep winter you need probably a few acres of panels.
Its practically impossible to go off grid based purely on solar in the UK.
Even places with massive solar installs that go off grid tend to have a diesel generator.

 

[jonneymendoza]

Right so yes we are back to hows that going to work.

Solar in the UK is highly seasonal in regards generation.

To have an array thats going to guarantee a useable amount in deep winter you need probably a few acres of panels.
Its practically impossible to go off grid based purely on solar in the UK.
Even places with massive solar installs that go off grid tend to have a diesel generator.

Yea it is impossible with today's tech for sure but basically my overall point was, can solar panel with battery "help" the cost of running a heat pump?

And can a heat pump deliver on demand hot water like a combi gas boiler does so you don't need spend extra and house a large hot water cylinder?

 

[b0rn2sk8]

Yea it is impossible with today's tech for sure but basically my overall point was, can solar panel with battery "help" the cost of running a heat pump?

And can a heat pump deliver on demand hot water like a combi gas boiler does so you don't need spend extra and house a large hot water cylinder?

Yes but only if you have spare capacity in the system that you are not already using. Most people don’t. You can of course size your battery storage accordingly.

No.

 

[jonneymendoza]

Yes but only if you have spare capacity in the system that you are not already using. Most people don’t. You can of course size your battery storage accordingly.

No.

Sorry can you explain further? Capacity for what?

Edit, you mean batteries?

Yea sure but you can put these in your loft and they are more manageable than a hot water cylinder tank.

So heat pumps require a hot water cylinder which if coming from a combi boiler, you won't have and need to have space for...

Which was yet one of my suggestion to what needs to be considered. You can't just switch a combi boiler with a heat pump. You need room for a hot water cylinder

 

[dirtychinchilla]

What is the SCOP of the install, would it make any difference to the running cost for the year if it is SCOP of lets say 2.5 or 4 ?

Absolutely. You get nearly double the output from the same input going from 2.5 to 4.0 SCOP.

Yea it is impossible with today's tech for sure but basically my overall point was, can solar panel with battery "help" the cost of running a heat pump?

And can a heat pump deliver on demand hot water like a combi gas boiler does so you don't need spend extra and house a large hot water cylinder?

You definitely want to have a hot water cylinder because then you can take advantage of heat generation when it's sunny, store the hot water, discharging the heat when you need it instead of when it's generated. Thermal storage is enormously advantageous and is something the UK needs to take much more seriously.

 

[b0rn2sk8]

Sorry can you explain further? Capacity for what?

Edit, you mean batteries?

Yeh it’s mainly batteries, as has already been noted, the good days of solar are few and far between unless you have a massive array compared to your consumption.

Yea sure but you can put these in your loft and they are more manageable than a hot water cylinder tank.

Hot water cylinders have always been superior in every way. Their only disadvantage is you need somewhere to put them.

It was always a bit short sighted to rip out a cylinder for a combi. Cylinders can deliver more hot water at higher pressures and they are more efficient and far easier to make more efficient.

While cylinders have heat loss (1-2kwh/day) the additional efficiency mainly comes down to being able to correctly size the boiler for heat rather than being oversized for hot water.

Combis also cycle constantly when drawing small amounts of hot water and it’s really inefficient.

So heat pumps require a hot water cylinder which if coming from a combi boiler, you won't have and need to have space for...

Yes, you can loft mount them. Older hoses often have massive roof timbers as they all used to have loft mounted tanks.

Which was yet one of my suggestion to what needs to be considered. You can't just switch a combi boiler with a heat pump. You need room for a hot water cylinder

See above, loft mounting is an option, as is within an integral garage. Some people even have them in an outbuilding on the side of the house (old oil boiler/coal sheds).

Many who ripped out their cylinders for combis still have their ‘airing cupboard’, they’ll have to put it back to its original use.

A heat pump isn’t the only solution - see something like a Tepeo (although they are pretty reliant on time of use tariffs being available with low night rates).

 

[dirtychinchilla]

Hot water cylinders have always been superior in every way. Their only disadvantage is you need somewhere to put them.

It was always a bit short sighted to rip out a cylinder for a combi. Cylinders can deliver more hot water at higher pressures and they are more efficient and far easier to make more efficient.

While cylinders have heat loss (1-2kwh/day) the additional efficiency mainly comes down to being able to correctly size the boiler for heat rather than being oversized for hot water.

Not quite true. They're inferior for domestic hot water because of the legionnaires risk. For heat pumps, not having to deliver 60C has massive benefits to the SCOP.

However, having additional thermal storage capacity is a great thing.

 

[b0rn2sk8]

Not quite true. They're inferior for domestic hot water because of the legionnaires risk. For heat pumps, not having to deliver 60C has massive benefits to the SCOP.

However, having additional thermal storage capacity is a great thing.

There is no legionnaires issues in a system which is correctly configured, this is no different to gas or heat pumps. At 45C and above its dormant which is below the temperature of the water (50C) and most actually die at 50C anyway. A heat pump or gas system will run a cycle once a to top the tank off to 60C for belt and braces.

While people often default a gas system to 60C+ because they lack suitable controls to do anything else, that doesn't make it ideal. Ideally it should be lower because of the scalding risk and for efficiency. You really don't need 60C water, almost all of it you pay more to heat it to 60C and then dilute it to a lower temperature anyway - its totally bizarre really.

I feel like we were clutching at straws there at little. What combi's are is cheaper to initially install (but have higher running costs...) and take up less space - there is no denying that but everything about their performance is worse.

 

[dirtychinchilla]

There is no legionnaires issues in a system which is correctly configured, this is no different to gas or heat pumps. At 45C and above its dormant which is below the temperature of the water (50C) and most actually die at 50C anyway. A heat pump or gas system will run a cycle once a to top the tank off to 60C for belt and braces.

While people often default a gas system to 60C+ because they lack suitable controls to do anything else, that doesn't make it ideal. Ideally it should be lower because of the scalding risk and for efficiency. You really don't need 60C water, almost all of it you pay more to heat it to 60C and then dilute it to a lower temperature anyway - its totally bizarre really.

I feel like we were clutching at straws there at little. What combi's are is cheaper to initially install (but have higher running costs...) and take up less space - there is no denying that but everything about their performance is worse.

You're not wrong about legionnaires, but why are you assuming that the water is 50C?

I'm on your side about heat pumps, don't worry. Just don't think that hot water storage is always better.

 

[robj20]

Got water storage certainly wasn't better for us.
One we got rid of our cylinder we saved money on hot water.
I'll be looking for solutions that don't require cylinders. Heatpump at the minute is not cheaper so is a no go for me.

 

[b0rn2sk8]

The COP starts gets hit above 50C and if you go substantially below 50C, say 40C, it will be below body temperature by the time it comes out the tap. There is only so low you can go, you might get away with 45C if its short runs and all the pipes are well lagged.

Got water storage certainly wasn't better for us.
One we got rid of our cylinder we saved money on hot water.
I'll be looking for solutions that don't require cylinders. Heatpump at the minute is not cheaper so is a no go for me.

Are you comparing a like for like system and not say an old cylinder and non-condensing boiler which was replaced with a modern combi? That is the logical fallacy most people fall down when they compare the two and in those cases you just can't.

The heat loss on a modern cylinder is only 1-2kwh a day (size dependent) which is nothing, its in rounding error territory (not to mention for the 5 months you have your heating on, the loss is ~zero as it leaks back into your house). Firing up a 30kw boiler to fill a washing up bowl uses considerably more energy than what you actually get in hot water.

 

[Mercenary Keyboard Warrior]

Got water storage certainly wasn't better for us.
One we got rid of our cylinder we saved money on hot water.
I'll be looking for solutions that don't require cylinders. Heatpump at the minute is not cheaper so is a no go for me.

Did you scrap a completely up to date boiler and tank?
Or did you do what most people do, scrap an old tank and old boiler and shock horror find that a newer one is more efficient.

I bet I could scrap a 15 year old combi, put in a modern system boiler and tank and prove that that is more efficient than a combi

 

[robj20]

Did you scrap a completely up to date boiler and tank?
Or did you do what most people do, scrap an old tank and old boiler and shock horror find that a newer one is more efficient.

I bet I could scrap a 15 year old combi, put in a modern system boiler and tank and prove that that is more efficient than a combi

No when we moved in the water cylinder was leaking so we replaced it with a brand new one.
Year or so later the boiler broke and we replaced it with a combi but kept the cylinder. (I fitted new central heating at the same time)
It was just easier until I could reroute the hot water pipes, we ran out like that for about 18 months, when we eventually got rid of the cylinder.

 

[b0rn2sk8]

So yes then

You posted earlier in the thread about swapping all the radiators for larger ones and running at lower flow temperatures.

 

[jonneymendoza]

Did you scrap a completely up to date boiler and tank?
Or did you do what most people do, scrap an old tank and old boiler and shock horror find that a newer one is more efficient.

I bet I could scrap a 15 year old combi, put in a modern system boiler and tank and prove that that is more efficient than a combi

My previous boiler and tank is probably older than you and me combined lol

My parents place diddnt have a hot water cylinder and just a combi boiler and wasn't a issue.

I have a family friend looking to remove his as it taking up lots of space lol.

With your hot water cylinder. How long does it keep the hot water, hot?

My mate said he only heats it up twice a day, morning and afternoon.

He has two sons and a wife living under the same roof so 4 people

 

[dirtychinchilla]

You have to have one with a heat pump FYI, so that the heat pumps can circulate water within their system

 

[Mercenary Keyboard Warrior]

My previous boiler and tank is probably older than you and me combined lol

My parents place diddnt have a hot water cylinder and just a combi boiler and wasn't a issue.

I have a family friend looking to remove his as it taking up lots of space lol.

With your hot water cylinder. How long does it keep the hot water, hot?

My mate said he only heats it up twice a day, morning and afternoon.

He has two sons and a wife living under the same roof so 4 people

Ive never left it insanely long. Last year or the year before I forget which our boiler broke. It was down for over 48 hours, the water was still hot when it was fixed.
We did use it but ofc its refilled with cold so you do drop the temps after using some of the hot.
It was certainly nice to be able to have a (quick) hot shower whilst the heating was broken!

I only heat mine once a day. Right now its 7-9pm.
I moved the time due to for a while using a diverter to send excess solar to my immersion.
Thats off again now since my gas price is lower than the export price I receive.

Right now Octopus keep giving me sessions of free elec from 2-4pm so I heat the water to full with elec at that time

In the middle of summer I was getting a full tank of hot water (ie topping up anything we used) for free

As b2sk8 says the modern tank losses are minimal. Mines now 14 year old iirc and even then its listed as around 2kwh of losses in 24 hours. TBH I probably lose more from the heating pipes that are in the cupboard that are un lagged.
We still use the airing cupboard for drying some things, like undies etc after washes in the winter.
My airing cupboard has a vent above the door so it has a very slow convection to send heat in there out onto the landing. The heat isn't lost, its mainly directed into the house.

 

[jonneymendoza]

Ive never left it insanely long. Last year or the year before I forget which our boiler broke. It was down for over 48 hours, the water was still hot when it was fixed.
We did use it but ofc its refilled with cold so you do drop the temps after using some of the hot.
It was certainly nice to be able to have a (quick) hot shower whilst the heating was broken!

I only heat mine once a day. Right now its 7-9pm.
I moved the time due to for a while using a diverter to send excess solar to my immersion.
Thats off again now since my gas price is lower than the export price I receive.

Right now Octopus keep giving me sessions of free elec from 2-4pm so I heat the water to full with elec at that time

In the middle of summer I was getting a full tank of hot water (ie topping up anything we used) for free

As b2sk8 says the modern tank losses are minimal. Mines now 14 year old iirc and even then its listed as around 2kwh of losses in 24 hours. TBH I probably lose more from the heating pipes that are in the cupboard that are un lagged.
We still use the airing cupboard for drying some things, like undies etc after washes in the winter.
My airing cupboard has a vent above the door so it has a very slow convection to send heat in there out onto the landing. The heat isn't lost, its mainly directed into the house.

When I had my old cylinder I would turn it on for a couple of hours whilst I was in the house doing some work (I wasn't living there yet).

The next day I come and the water was luke warm at best and needed to reheat the hot water cylinder again.

This was between Jan to march time this year when it was super cold.

 

[robj20]

So yes then

You posted earlier in the thread about swapping all the radiators for larger ones and running at lower flow temperatures.

So no.

That's for heating not hot water. I don't use the heating in summer. We were only taking about hot water ie the use of a cylinder.