Need help please

[Nic]

Ok I little knowledge is a dangerous thing, but no knowledge is even worst . 
so we are having a small two bed 1.5 story house built timber frame in Devon. Whilst I know I will need lights and sockets etc and I can work out for myself where I might need them . The house will be built to high passive and airtightness. My problem is ideally I need to sit down with someone who knows and can link up all the bits I need to work at the heart of the home so the ASHP, MVHR, solar, battery, UFH and DHW and cylinder. Is there someone who can have knowledge across all these areas and make it all work seamlessly? ( as near as)

when I contact, say someone about MVHR and they say things like “we only deal with these we don’t get involved with solar or ASHP” etc etc 

 

🤷🏻‍♂️

 

 

Edited March 12 by Nic

[joe90]

Welcome, you will find various threads exist on these individual subjects and various opinions. Have you read previous threads.?

[Moonshine]

Where in Devon are you? I am in Devon and just done a build with ufh, ASHP, and cylinder and can provide some input. I looked at mvhr but decided against it.

 

Maybe post some drawings up and we can all look at the best way to fit it in. 

 

Also I have some ufh pipe and a manifold cabinet I am looking to get rid of if you need some

Edited March 12 by Moonshine

[nod]

6 hours ago, Moonshine said:

Where in Devon are you? I am in Devon and just done a build with ufh, ASHP, and cylinder and can provide some input. I looked at mvhr but decided against it.

 

Maybe post some drawings up and we can all look at the best way to fit it in. 

 

Also I have some ufh pipe and a manifold cabinet I am looking to get rid of if you need some

Sounds like a result 

[SteamyTea]

Some things, DHW, Space Heating and MVHR are in reality, separate, so should be treated as such.

DHW can be dealt with in 2 ways.  Heated and stored for later usage, instantaneously heated when needed.

MVHR is just ventilation, it saves you opening the windows.

 

The confusion starts when the heat source for DHW and the space heating are the same unit.  We have got used to that with combi gas boilers, but they work in the same way as a heat pump, but just at a different power level.  The word power is important there, it is not temperature or energy.

Basically, you put water in one side, hotter water comes out the other which you then use to heat the house or a cylinder for your hot water (or use directly).

So the only controls you need is a diverter valve to push the water into either the heating system or the DHW system.  The problem comes because you want the heating system at a lower temperature (generally) than the DHW temperature.  That is set up by the boiler/heatpump control system.

It may seem complicated when people start talking about different temperatures and flow rates, weather compensation or load compensation, but all that really means is that the maximum power point is not always the same as the maximum efficiency point (like a car, too low in the rev band and it will still die, too high up the rev band and it will use a lot of fuel).

 

Batteries and PV are a bit more complicated as they are more to do with your usage pattern and the amount of generation on the day in question.

There is a lot being made of how great batteries are, but they are still an expensive form of getting electricity to power something.  Just because the energy used charge them may be cheap, or seemingly free if from your own PV, there is still a cost because they do not last forever, and if you don't use most of your stored energy, then the next charging opportunity is missed.  Sometimes this energy can be diverted to the DHW, but if that is already 'full' then it gets exported.

 

Initially I would treat each part individually and monitor what is happening (well worth spending £100 on a decent logger), then after a year or two, start to tweak the systems, which may involve buying some extra kit, usually more sophisticated controllers.

 

Where you are near Exmouth has a similar climate to where I am, warm, lots of rain, burst of powerful sunshine, and always windy.  You cannot control those elements.

 

So.

Set up MVHR and let it do what it is designed to do, change the air and recover some of the energy in it.

Set up the heating system to deliver at the lowest temperature and flows possible i.e. weather compensation.

Set up a diverter on the PV system to charge batteries first, then divert to the DHW cylinder.  You can try running heavier loads like a washing machine around noon, but these days washing machines are very energy efficient, I think mine uses about 300 Wh for a load, 10p worth of the most expensive day rate electricity that EDF can supply me.

Make sure you don't have parasitic loads draining your system, I used to use an old desktop PC to monitor my energy usage, it drew 300 W of power constantly.  I now use a Raspberry Pi that uses so little that it is basically unmeasurable.

Buy the lowest power/highest efficiency fridges and freezer you can get, they really do make a difference. @Radian (not seen him around for a bit) bought a new fridge that uses less energy than my much smaller one, and mine only uses 5W.

 

If you really want to save energy, get a more economical car. My current car uses 700 Wh/mile (65 MPG) but an EV can easily halve that.

 

And monitor and analysis your usage.

Edited March 13 by SteamyTea

[Nic]

7 hours ago, Moonshine said:

Where in Devon are you? I am in Devon and just done a build with ufh, ASHP, and cylinder and can provide some input. I looked at mvhr but decided against it.

 

Maybe post some drawings up and we can all look at the best way to fit it in. 

 

Also I have some ufh pipe and a manifold cabinet I am looking to get rid of if you need some

mum currently in Portsmouth but will be in Exmouth . Thanks again that’s a great help 

[Moonshine]

7 minutes ago, Nic said:

mum currently in Portsmouth but will be in Exmouth . Thanks again that’s a great help 

 

Try https://www.neutralenergysolutions.co.uk/ 

 

Also there is these guys around for solar / storage.

 

https://www.365energyltd.com/

 

Also unitherm have a base in Exeter and can provide LG kit and parts easily.

 

https://www.unitherm.co.uk/

[Nic]

6 minutes ago, SteamyTea said:

Some things, DHW, Space Heating and MVHR are in reality, separate, so should be treated as such.

DHW can be dealt with in 2 ways.  Heated and stored for later usage, instantaneously heated when needed.

MVHR is just ventilation, it saves you opening the windows.

 

The confusion starts when the heat source for DHW and the space heating are the same unit.  We have got used to that with combi gas boilers, but they work in the same way as a heat pump, but just at a different power level.  The word power is important there, it is not temperature or energy.

Basically, you put water in one side, hotter water comes out the other which you then use to heat the house or a cylinder for your hot water (or use directly).

So the only controls you need is a diverter valve to push the water into either the heating system or the DHW system.  The problem comes because you want the heating system at a lower temperature (generally) than the DHW temperature.  That is set up by the boiler/heatpump control system.

It may seem complicated when people start talking about different temperatures and flow rates, weather compensation or load compensation, but all that really means is that the maximum power point is not always the same as the maximum efficiency point (like a car, too low in the rev band and it will still die, too high up the rev band and it will use a lot of fuel).

 

Batteries and PV are a bit more complicated as they are more to do with your usage pattern and the amount of generation on the day in question.

There is a lot being made of how great batteries are, but they are still an expensive form of getting electricity to power something.  Just because the energy used charge them may be cheap, or seemingly free if from your own PV, there is still a cost because they do not last forever, and if you don't use most of your stored energy, then the next charging opportunity is missed.  Sometimes this energy can be diverted to the DHW, but if that is already 'full' then it gets exported.

 

Initially I would treat each part individually and monitor what is happening (well worth spending £100 on a decent logger), then after a year or two, start to tweak the systems, which may involve buying some extra kit, usually more sophisticated controllers.

 

Where you are near Exmouth has a similar climate to where I am, warm, lots of rain, burst of powerful sunshine, and always windy.  You cannot control those elements.

 

So.

Set up MVHR and let it do what it is designed to do, change the air and recover some of the energy in it.

Set up the heating system to deliver at the lowest temperature and flows possible i.e. weather compensation.

Set up a diverter on the PV system to charge batteries first, then divert to the DHW cylinder.  You can try running heavier loads like a washing machine around noon, but these days washing machines are very energy efficient, I think mine uses about 300 Wh for a load, 10p worth of the most expensive day rate electricity that EDF can supply me.

Make sure you don't have parasitic loads draining your system, I used to use an old desktop PC to monitor my energy usage, it drew 300 W of power constantly.  I now use a Raspberry Pi that uses so little that it is basically unmeasurable.

Buy the lowest power/highest efficiency fridges and freezer you can get, they really do make a difference. @Radian (not seen him around for a bit) bought a new fridge that uses less energy than my much smaller one, and mine only uses 5W.

 

If you really want to save energy, get a more economical car. My current car uses 700 Wh/mile (65 MPG) but an EV can easily halve that.

 

And monitor and analysis your usage.

 

I'm so grateful this is really helpful. 
I’ll be near to Raddenstile Lane in Exmouth 

due to the small roof are ? Only two bed and Velux’s in roof as well we are limited to about 3.48kw of solar , with a 5.76kw battery ( quote £8500 fitted inline ) 

 

looking at the Zehnder 250 flex ceiling mount

to save space in utility  room . Not considered best external ASHP yet or DHW cylinder and just a single zone ground floor UFH system . Very limited internal space for this about 1m2 with the MVHR in the ceiling. 
 

many thanks again . Total floor area over two floors is going to be 110m2 and Norrsken windows and walls will be around  au value of 0.11-12 Velux will be the new passive range 

 

[Moonshine]

Are you at planning stage or have you got build regs drawings done yet? Layouts would really help

 

I presume you are only having ufh on ground floor and rads on first?

 

You need more than one zone on ground floor and you are limited that ufh circuits should be less that 100m long. Sounds like you will have 3-4 pipe circuits and need to find space for 4 circuit manifold, pump, and control unit. This can be placed in a timber stud wall in a recessed cabinet if space is a premium.

 

This is what we did.

 

 

As for cylinder you can get combined cylinder and buffer tank in one unit. We used world heat pre plumbed. Have a look at a 200-250 ltr tank for indicative size.

[SteamyTea]

7 minutes ago, Nic said:

quote £8500 fitted inline

My day rate electricity is currently 37p/kWh (and getting cheaper by the quarter).

So £8500 / 0.37p/kWh = ~23 MWh

 

12 minutes ago, Nic said:

Total floor area over two floors is going to be 110m2

That is about double my area.

I use around 3.3 MWh/year, and I have no technology at all, just insulation and airtightness.

So if you use double that, and if you fit an ASHP you will use a lot less, that is 3.5 years worth of electricity, and nearly £500 a year on lost interest.

 

PV on its own is probably worth while, as long as you do not get a silly price to install it and 3.5 kW_p is a usable amount.  You can probably use 2/3^rd of that, which amounts to 2.3 MWh/year.

 

Leave the batteries until a later date.

 

20 minutes ago, Nic said:

Not considered best external ASHP yet or DHW cylinder

A 5 kW monoblock ASHP will probably do you, as will a 200 litre cylinder.

21 minutes ago, Nic said:

just a single zone ground floor UFH system

All you need, keep it simple.

[SteamyTea]

7 minutes ago, Moonshine said:

You need more than one zone on ground floor

This may need a bit of clarification.

There are Zones and Circuits.

1 circuit can have many zones.

 

Basically the zones are connected together in parallel and act as 1.

Different pipe spacing can change the amount of power that is delivered to different rooms.

 

7 minutes ago, Moonshine said:

Are you at planning stage or have you got build regs drawings done yet? Layouts would really help

That is a good point, if not built yet then it is the time to review the thermal losses.

Edited March 13 by SteamyTea

[Moonshine]

2 minutes ago, SteamyTea said:

9 minutes ago, Moonshine said:

You need more than one zone on ground floor

This may need a bit of clarification.

There are Zones and Circuits.

1 circuit can have many zones.

 

It think it depends a lot on the room layouts as you don't want have a room on ground floor that is barely used and heated unnecessarily if on the same zone as a more frequently used space.

[SteamyTea]

6 minutes ago, Moonshine said:

It think it depends a lot on the room layouts as you don't want have a room on ground floor that is barely used and heated unnecessarily if on the same zone as a more frequently used space.

Yes, to a certain extent.

In a small place like mine, it would make no difference, but if the place is a more complicated than a simple rectangle, there may possibly be savings to be made.

It is why we do room by room heat loss calculations, they show up this sort of thing and help make the decisions.

[Nic]

Something like this,  not set in stone on utility room layout ( probably stack washer and dryer , move toilet and MVHR as ASHP will be on the external wall where to toilet currently is located 

[Moonshine]

i would stay you best bet is to out the UFH stuff in a recessed cabinet between the WC and kitchen about here, opening into the WC. However this timber stud work wall has to be thicker to accommodate it so you will loose some floor area

 

 

https://www.wundatrade.co.uk/shop/home/underfloor-heating-manifolds-and-pump-sets/underfloor-heating-manifolds/medium-recessed-waterproof-manifold-cabinet/

[SteamyTea]

@Nic

 

Are the grid squares 0.5m?

[ProDave]

15 minutes ago, Moonshine said:

i would stay you best bet is to out the UFH stuff in a recessed cabinet between the WC and kitchen about here, opening into the WC. However this timber stud work wall has to be thicker to accommodate it so you will loose some floor area

 

 

https://www.wundatrade.co.uk/shop/home/underfloor-heating-manifolds-and-pump-sets/underfloor-heating-manifolds/medium-recessed-waterproof-manifold-cabinet/

I fitted the UFH manifold in my bathroom into a 100mm space. I had to turn the pump in it's side and remove the knob from the blending valve.  You can usually borrow 50mm space behind the kitchen cabinets as well.

[ProDave]

23 minutes ago, Nic said:

 

 

How are you achieving means of escape windows in the bedrooms?

[Moonshine]

17 minutes ago, SteamyTea said:

@Nic

 

Are the grid squares 0.5m?

 

the external patio grid is 0.6m

[Nic]

1 hour ago, SteamyTea said:

@Nic

 

Are the grid squares 0.5m?

Not sure but internally the space is 9300mm x 6000mm 

[Nic]

1 hour ago, ProDave said:

How are you achieving means of escape windows in the bedrooms?

Good question, architect has not mentioned that so I suspect that will need to be addressed

[Moonshine]

29 minutes ago, Nic said:

Not sure but internally the space is 9300mm x 6000mm 

 

From my finger in the air calcs, if UFH pipe spacing is 150mm in the screed (usual for an ASHP), you are looking about 6.7 linear metres of pipe per m2. 56m2 will be 372 linear metre of pipe at least. So you are looking at 4 circuits (being <100m), maybe 5 depending on zoning.

 

As @SteamyTea noted all these circuits can be in one zone and controlled by one thermostat, which may be apt as its open plan on the ground floor, but i would probably go for a separate zone and circuit in the WC / Utility.

Edited March 13 by Moonshine

[JohnMo]

8 minutes ago, Moonshine said:

i would probably go for a separate zone and circuit in the WC / Utility.

I really wouldn't install loops in these rooms, your manifold will be in this room and all the pipes having to go through the doorway. Big curve through that room with the pipes will provide more than enough heat.

 

Then just do it all a single zone

[Moonshine]

Just now, JohnMo said:

I really wouldn't install loops in these rooms, your manifold will be in this room and all the pipes having to go through the doorway. Big curve through that room with the pipes will provide more than enough heat.

 

Then just do it all a single zone

 

i respectfully disagree 😉. The pipes won't need to go through the WC and its doorway, if they are coming up out of the screed into a timber stud wall / recessed cabinet, they can go 'south' into the kitchen (maybe 3 circuits) and spread out, with one circuit going 'north' into WC. This way the heat requirement of the WC is separate to the main living areas and it won't over heat in the WC. 

[Moonshine]

2 hours ago, Nic said:

ASHP will be on the external wall where to toilet currently is located 

 

Be careful where you put the ASHP as if this is where i think it is, there is a neighbour window very close by and this location may not be suitable for noise and MCS020 criteria (if you are going down that route)