Help,where do we site heat pump and all the gubbins?

[Selfbuildsarah]

We have come to realise that we may not have sufficient storage space for the heat pump, MVHR, solar PV and water storage gubbins inside the house. Being somewhat green we just accepted when our designer sectioned off a corner of the garage as a plant room without question. Could I have examples of where all the “gubbins” are in your house and how you managed to squeeze them in. Do they all need to be together or can they be separated? I imagine we can put the MVHR unit in the loft but apart from that how do you fit it all in? I haven’t seen a real life set up so have no idea how much space is actually needed so photos appreciated.
Attached is a very rough pic showing position of garage, plant room at back and where we planned to put heat pump. Not to scale 🤣

[ProDave]

We found you need very little "plant room" space, and it all ended up distributed around the house.

 

A Monoblock Air source Heat Pump, most of the works are outside.  You might need some pumps, valves and expansion vessels etc inside somewhere.

 

Hot water tank wants to be positioned central to points of hot water use to minimise delivery time.  Ours is in an airing cupboard partitioned off a bedroom.

 

MVHR is best in a warm part of the house, but can be put in a loft id the ducting is properly insulated.

[saveasteading]

Ours for reference. There is now more pipework but the same space taken up.

[joth]

55 minutes ago, saveasteading said:

Ours for reference. There is now more pipework but the same space taken up.

Good example of ASHP and plumbing internal gubbins.

 

Solar PV won't add much onto that, but ideally goes somewhere that stays cool in summer. (indoors may well be the best you can do there. Ours is in garage)

If you add a house battery that's a lot more space. Ideally indoors, ours is in garage - does not perform well in winter.

 

The MVHR takes a about half as much as the HW tank shown there. Best Location depends on the routing of all the ducts to every room - ours is on the loft.

 

 

[Selfbuildsarah]

@saveasteading thankyou, that’s very helpful. Is that a 300L water tank? What are the 2 vessels on the right? (Told you I was green!)

How close is your heat pump? Do you have UFH? Many thanks.

 

[SteamyTea]

Don't forget that you can hang a lot of stuff on the walls.

 

Was listening to Costing the Earth yesterday, Steve Backshall Goes Off Grid.

 

Apart from getting his sensible and latent heat mixed up, and not giving a cash price on what he spent, he said one interesting thing about his plant room.

'it is hot in here'

Sounds like he has not insulated enough.

So make sure you have enough room to add extra insulation to everything. Manufacturers of cylinders and tanks may boast about how great the levels are, but if a room gets hot, it isn't good enough.

[Selfbuildsarah]

@joth Thanks for your reply. We are probably going to be grid tied and not have a battery. Only pv tiles on south facing garage roof. You say it doesn’t perform well in winter. Is that because it’s not in a plant room or insulated?

If we steal part of a room (gym for example) can we partition it off closely (in effect making it a cupboard) or does it need to have space around it?

Do all the components have to be together or can they be split up to enable us to fit them in where it’s more convenient? Thanks again.

[SteamyTea]

Just now, Selfbuildsarah said:

Only pv tiles on south facing garage roof

Why tiles, they are an expensive option.

Some PV inverts can live outside, or use micro inverts below the modules.

[Selfbuildsarah]

@SteamyTea so much to think about! We’ve been told that having the gubbins in the plant room and ASHP on the back of the garage will be too far from the house,which is why we are rethinking it all. “Should have designed the house around the plant room”!

[crispy_wafer]

I think you need to define gubbins in a bit more detail to work out how much room you may need.  My plant room (cupboard) is 1.2*1.2, will house the cylinder which is about 600mm diameter.  Expansion vessels will be wall mounted, and the hot and cold water manifolds will be wall mounted high up too.  Pipework will run round the perimeter.  The UFH manifold are located under the stairs (centrally in the house) so just a supply and return pipe to this.  MVHR is in the insulated attic space.  there will be 1 Consumer unit too.  The challenge is placing everything so that access and maintenance isn't too much of a challenge.

[Selfbuildsarah]

@SteamyTea Only a small area, less ugly and less susceptible to wildlife nesting. We are in a very rural location.

Edited May 25, 2023 by Selfbuildsarah
Omission

[Selfbuildsarah]

@crispy_wafer yes, and for me it’s knowing which elements can be housed in isolation and which need to be closest to the ASHP or must be located together. I wonder if the tank can go under the stairs 🤔 but not sure if this needs to be close to the HP. Thanks for your help.

[crispy_wafer]

I'm sure for best efficiency installers like the two to be close, however, as long as pipework is properly insulated, and depending on distance the install may need a second pump to help push the water along...

[joth]

6 hours ago, Selfbuildsarah said:

You say it doesn’t perform well in winter. Is that because it’s not in a plant room or insulated?

This was with respect to the solaredge battery.

Batteries in general don't work well in the cold, reduces capacity and can't work them as hard. Or battery ended up with inverter in the garage which is outside temperature, more or less. So poor place for storing energy in winter (mostly for time shifting to make use of overnight cheaprate electric)

 

 

[Bozza]

My ASHP tank etc, is in a cupboard 1mx1m along with other relevant bits - fuse boxes, electricity meter, mains stop clock and ironing board.    No solar or MVHR.

 

 

 

 

[Selfbuildsarah]

@Bozza how close to your heat pump?

[Bozza]

16 hours ago, Selfbuildsarah said:

@Bozza how close to your heat pump?

3 metres ish

[SteamyTea]

The only thing that may cause a real problem is if you cannot get your batteries close to your inverter.  The reason for this is that the DC cables have to be large, AC ones don't.

The general rule with ''renewable energy' installations is to keep all cable voltage drop to below 1% (I think this comes from a metering issue where placement of the meter can show different generation amounts).

When it comes to pipework, just insulate it more than you think you need to.  This can be as simple as boxing in pipes and filling with mineral wool.

[Pocster]

My uvc is probably 10m from the ASHP - all pipework insulated of course . Batteries outside are temperamental to temperature unless a Tesla ( has cooling and heating ) . My inverter outside also - about 1m from batteries . No issues 

[Dave Jones]

make room for at least 2 tanks unless you enjoy cold showers.

[JohnMo]

You would cheaper to just top up temperature with your immersion, if you needed too. A constant standing loss for each cylinder would be 1.5 to 2kWh per day. So not sure why you would want that.

 

Or just add an inline electric heater, use your single cylinder as the main source of hot water, heated by ashp, then if the temperature drops below a set level, the inline heater kicks in.

 

 

[Selfbuildsarah]

16 hours ago, Dave Jones said:

make room for at least 2 tanks unless you enjoy cold showers.

😳😬

[Selfbuildsarah]

15 hours ago, JohnMo said:

You would cheaper to just top up temperature with your immersion, if you needed too. A constant standing loss for each cylinder would be 1.5 to 2kWh per day. So not sure why you would want that.

 

Or just add an inline electric heater, use your single cylinder as the main source of hot water, heated by ashp, then if the temperature drops below a set level, the inline heater kicks in.

 

 

Most of the time there will be just the two of us but sometimes when family visit quite a lot more. Don’t want the embarrassment of running out of hot water.

[SteamyTea]

1 hour ago, Selfbuildsarah said:

Most of the time there will be just the two of us but sometimes when family visit quite a lot more. Don’t want the embarrassment of running out of hot water.

Cylinders can be reheated right after usage, they don't need to wait until the bathroom is vacated.

 

I would think that most households have the same problem regardless of heat source.

If a combi boiler has a flow rate of 10 lt/minute at the desired temperature, it can reheat a cylinder at pretty much the same rate as it can come out the tap.

Really down to the power of the system, not the volume stored.  Not as if anyone uses hot water when it is too cold bath in i.e. <35°C, so the cylinder is not totally cold i.e. ground temperature ~8°C.

 

As @JohnMo says, if you are really worried, get an inline heater or just fit a couple of immersion heaters.  Immersion heaters are the cheap option.  5.5 kW of heating into a 300 lt cylinder will raise it by 20°C in just over an hour.  If the flow rate of a shower is 10 lt/minute, that would supply 3, ten minute showers an hour, but in that same hour, more than half the energy would have been replaced, so 5 showers an hour.

And that is just for a 20°C replacement rate.

Cost to run would be about £3.50, near enough the same as a Costa Coffee, and that only has 0.25 litres of hot water in it.

We also should be striving to us less water overall.  This year I have reduced my usage by around 50 litres a day, I don't think my life has suffered, or my personal hygiene.  Can't say the same for the car, that is pretty grubby, by my succulents in the garden don't seem to care if they have water or not.

 

If you are mainly shower people, rather than bath people, have you considered getting waste water energy recovery.

That will save on running costs and reduce reheat times.

Edited May 28, 2023 by SteamyTea

[Dave Jones]

10l flow is pathetic. may as well use a bucket and cloth! double that.

 

very expensive to heat on demand in daytime so not a good idea, you want to aim for overnight heating at cheap rate and have enough hot water to last through the day at a realistic usage. No way would a single tank be enough for a family with teenagers.

 

remember ASHP cant do heating and hot water at same time either. 

 

The only thing going for ASHP over a gas boiler is its cheaper to run, everything else is a negative.