Building a "stealth bungalow"

[adam2]

Latest plans WRT electrical installation.

Three phase 100 amp service.
FOUR PV installations, one for battery charging and three grid tied, one per phase.
Battery charging installation to be based around 2Kw of PV and a 24 volt battery of at least 2,000 AH.
Lighting to be half from mains and half from 24 volt battery supply.

IT equipment in farm managers office to have manual changeover between mains and battery supply.
Battery operation to be the norm in summer, to use otherwise surplus power, mains operation to be the norm in winter when PV input is less.
Battery operation possible at any time in case of power cuts.

[kenneal - lagger]

........Limited under floor heating via microbore semi flexible copper tube to be pulled into wider bore plastic tube that is to be cast into the floor slab. ...............

Why bother with the copper tube? Just use proper plastic under floor heating pipe like thousands of other installations do around the world. Much cheaper and much more efficient.

[adam2]

The concern is future leaks. The proposed microbore copper pipes can be withdrawn from the ducts and replaced with new, should this be required.

It is not proposed to apply underfloor heating to the workshop area as this will often be exposed to the outside air.
Nor to the mess room area as this will be directly heated by the stove.

[vtsnowedin]

The concern is future leaks. The proposed microbore copper pipes can be withdrawn from the ducts and replaced with new, should this be required.

It is not proposed to apply underfloor heating to the workshop area as this will often be exposed to the outside air.
Nor to the mess room area as this will be directly heated by the stove.

My daughters house has radiant on all floors including cast into the basement floor concrete. The tubing is all pex. When it comes from the boiler it goes to manifold tubes and each loop of the dozen or so in each floor can be shut off by valves at each end of every loop. They could lose half of the loops and still heat the floor. Ten years on and no leaks yet but I have had to do some flushing of sediment to keep some zones working properly.

[kenneal - lagger]

The concern is future leaks. The proposed microbore copper pipes can be withdrawn from the ducts and replaced with new, should this be required. ...

Put up a big notice saying "Don't drill holes in the floor" and you should be OK. I built in plastic u/f heating forty years ago and it's still going strong with no leaks.

I would be very surprised if you could draw copper pipe through a conventional U/f heating system loop let alone withdraw it and redraw more.

[adam2]

Final plans.
Multifuel stove with back boiler.
Gravity circulation to a very large hot water tank above the stove.
Pumped circulation from this tank to underfloor heating.
Gravity flow to hot water taps, and to shower mixers.
If the water in the hot water tank gets too hot, a battery operated bell will give warning of this.

The foundations slab has been cast, insulation board atop this, and then the concrete floor with ducts for underfloor heating.

Most of the other building work is on hold due to coronavirus.

[vtsnowedin]

Final plans.
Multifuel stove with back boiler.
Gravity circulation to a very large hot water tank above the stove.
Pumped circulation from this tank to underfloor heating.
Gravity flow to hot water taps, and to shower mixers.
If the water in the hot water tank gets too hot, a battery operated bell will give warning of this.

The foundations slab has been cast, insulation board atop this, and then the concrete floor with ducts for underfloor heating.

Most of the other building work is on hold due to coronavirus.

Rather then a bell that has to have someone present to hear and act on it would it not be better to have it dump excess heat to the floor. The thermal mass can act as quite a shock absorber?
.

[adam2]

Yes, the normal mode of operation will be that heat will be dumped into the underfloor heating.
The warning bell will be a second line of defence in case such arrangements fail for any reason. The thermal store will be large enough that the ringing of the warning bell will give plenty of time to let the fire go out. Or run some hot water to waste.
Or replace any defective circulating pump.

[fuzzy]

Make everything non expert replaceable. Isolating valves before and after pump, flexihoses to pump, pump on a power socket, easy way to top up system somewhere after messy replacement etc.

[kenneal - lagger]

Make everything non expert replaceable. Isolating valves before and after pump, flexihoses to pump, pump on a power socket, easy way to top up system somewhere after messy replacement etc.

And hold a stock of spares for the replaceable bits.

[adam2]

All equipment will be designed to be user repairable, with spares stocked.
The heating circulating pumps will be duplicated, and several spares stored on site.
And yes, flexible connections and isolating valves to facilitate easy replacement.
An open vented system is planned with gravity supply from a cold water cistern.

[adam2]

Now substantialy complete and in use.
Concrete block construction as earlier disscussed.
Heating from solid fuel stove. Gravity circulation from stove to large thermal store above, 2,400 liters. Gravity domestic hot water flow to taps and to showers. Pumped circulation to central heating, pumps duplicated and spares stored. 24 volt pumps. Stove to burn wood under normal conditions, but can also burn smokeless fuel if required. Estimated 12 tons of wood stored.
Summer hot water by immersion heaters in same thermal store.
Limited cooking possible on solid fuel stove, electric cooker as well. Mains fridge freezer, two 24 volt DC freezers.

3 showers, 3 toilets, 2 washing machines, drying room, changing room for up to 10 staff (more than ordinarily employed)

Mains electricity supply is 3 phase 100 amp. 3 grid tied PV installations, one per phase.
24 volt battery charging PV system, supplies about half the lights, the freezers, and the heating pumps.

Farm managers office can be supplied from mains or battery, manual changeover.

There is no intention that anyone should illegally live in the building whilst times are normal, but it remains a possibility in case of any future emergency.

[clv101]

Mains electricity supply is 3 phase 100 amp. 3 grid tied PV installations, one per phase.

Am I right in thinking the power company is compelled to accept something like 16A of PV per phase, but can refuse any more than that? Is that the reason for splitting the PV over the three phases?

[adam2]

Yes, grid tied renewable energy installations up to 16 amps per phase are generally permitted with relatively little paper wotk and enquiry.
Larger installations are not specificaly prohibited but are subject to potentialy expensive enquiries and assesments.

Small installations of up to 16 amps per phase CAN be rejected under certain circumstances , but there is a "presumption that they will be permitted in most circumstances"

[BritDownUnder]

Strange about the small amount of power per phase allowed. In Australia it is 5kW definitely and I was allowed 8kW as not many installations in my street. I have heard in the future that the export limit may be cut to zero if the power company thinks it will affect line voltage. I think three phase limit for home solar is 15kW. Solar gets almost a free run. If you want to grid connect wind or small hydro in Australia it is something akin to a public enquiry in terms of cost and expense. Lord Longford would be smiling in heaven.