Posts Tagged ‘Solar Hot Water’

Woodburning Stoves for Heating & Hot Water in Smokeless zones (update)

A quick update to my post yesterday on Woodburning Stoves for Heating & Hot Water in Smokeless zones. I’ve just had it confirmed by Rayburn/Aga that they do no wood-fired boiler models which are suitable for smokeless zones. So that means that I should update my Bin your Aga – buy a Rayburn post to “Bin your Aga and Rayburn – A Dunsley Yorkshire’s the only one for me”, and it means I can kiss my prospects of a Rayburn Solar Thermal System goodbye too. 

Maybe it’s time to move to the country 🙂 or look for alternatives to a wood-fired stove for my back-up water heating.

Woodburning Stoves for Heating & Hot Water in Smokeless zones

dunsley-yorkshireWe’re slowly narrowing the field in our wood-fired heating search. Following up on my previous posts on Woodburning Stoves for Heating & Hot Water and Using a Wood-Burning Stove in a Smoke-Control Area, I’ve found an interesting thing:

The Dunsley Yorkshire is the only stove with a back boiler that can be legally used in a smokeless zone

They cost £1922.30 for the wood-only version or £2218.40 for the multi-fuel.

So, if we’re looking at a wood-fired top-up to our solar hot-water that the sort of outlay we’re looking at.

The other consideration is overheating the house – if we succeed in super-insulating the house then having 4.5kw coming out of the Yorkshire into the room might cook us all! I’ll have to do the calculations, and look at how SIP and PassivHaus houses heat their hot water.

Water-efficient shower head

ecocamelJust seen the EcoCamel aerating showerhead – their test results claim a more pleasant shower with almost 50% of the water consumption of a standard shower. At the moment they are £40 for two – not the cheapest option, but a major saving if they work as forecast. Not only do you save water, but also they save the energy required to heat that water – assuming you’re not a devotee of cold showers! Potentially it could also mean that you ned to install less Solar Hot Water panels, which would be a significant saving!

Get paid for your Solar Hot Water

solarthermal-300x225This sounds a bit too strange to be true, but it does appear to be above board. I’ve emailed them to check and we’ll see what the response is. 

Anyway, what am I talking about? Good Energy – suppliers of 100% renewable electricity – are just starting to roll-out a Renewable Heat Incentive. On this programme they will pay you 4.5p per kWh you produce. Don’t worry, you do not need to work out a clever way to trasport the hot water back to Good Energy – you can keep using the hot water, your bank account just gets an additional warm glow too.

Shopping List – latest update

Steadily firming up the shopping list for our new house – here’s the latest list, with links. 

Kitchen

Dining Room

  • Expandable table

Playroom

  • Instant-heat to stand in front of (Gas?)

Lounge

  • Wood-fired stove
  • Central Pendant light in diffusing shade – 12v CFL?
  • Two Standard/Reading Lamps – 12v CFL?

Garden

  • Kitchen Scraps Compost: Black Soldier Fly Composter / Worm Farm 
  • Firewood store, and at least 12m³ of wood
  • Greenhouse with Aquaponics system

Heating & Hot Water

Power & Light

Water

Wood-Fired Ranges in a PassivHaus

In my PassivHaus Renovation post I said that:

Any non-solar water heating to be Gas Condensing boiler or CHP – wood fired stoves are not permitted (this conflicts with my peak-oil resilience planning)

In return I got a comment posted by Andy Simmonds at the AECB stating:

The AECB standards do not proscribe wood stoves, nor does the german version of the PassivHaus standard.

I’ve been back to the AECB standards and here are the sections of the Proscriptive Standard that deal with heating & cooking:

Space heating (Silver Standard):

Normally radiators or underfloor pipes. Fed from SEDBUK A-rated mains gas condensing boiler, CHP or, outside the gas supply area, SEDBUK A-rated LPG or oil condensing boiler, earth-source heat pump (seasonal COP ≥3.0) or cleanburning biomass boiler; i.e, one using liquid or gaseous fuels. Wood pellet boilers are permitted outside the gas supply area but are not encouraged due to the exhaust emissions. Blocks of flats or maisonettes to have a central boiler and/or CHP plant or heat mains connection; i.e. heat distribution within the block rather than individual boilers or electric heating.

Space heating (Gold Standard):

Normally hot water coil(s) in ventilation ductwork. Circulating pump consumption ≤0.1 W per m2 floor area or pro rata; e.g., Grundfos Alpha Pro or equiv. Heat sources as for Silver.

Cooking (Gold Standard):

Hobs gas, LPG, electric induction or clean-burning biomass – liquids or gases only. Ovens gas, LPG or electric A-rated. Electric min. A+ or A++

I don’t see anything in there which suggests a wood-burner would be permitted? I’ll have a chat to Andy and see if he can clarify things for me!

A Passivhaus (Passive House) renovation?

passivhaus_thermogram_gedaemmt_ungedaemmt

The picture on the left is a thermograph – showing the difference in lost heat between a conventional house (on the left) and a house built to PassivHaus standards (on the right). Which house would you rather be living in when Russia cuts gas supplies

The PassivHaus standard, as interpreted for the UK by the AECB, should result in an 80% reduction in a house’s energy consumption. PassivHaus design concentrates on three areas: improving the air-tightness of the house, reducing heat bridges, and, to a lesser extent, considering heat gain from the sun.

In essence, a typical passivhaus is air-tight & super-insulated, with mechanical ventilation with heat recovery (referred to as MVHR) to solve the issue of internal air quality. I had always believed that a PassivHaus needed no extra heating, but apparently that’s not entirely true. While they’ll generally have no radiators or underfloor heating, they often do have a small heating element within the ventilation system. In general they require about 30cm of insulation, and windows that are triple glazed.

Here are some of the key points of interest to me from the AECB version of the standard:

  • Use daylight to displace use of electric light
  • Solar hot water system required to deliver at least 50% of hot water
  • Walls, Floors, and Roof to all have U values of <= 0.15W/m2K
  • Doors (uninstalled) should have a U value of <= 0.6 W/m2K
  • Windows (uninstalled) should have a U value of <= 0.8 W/m2K, with a solar energy transmittance (inc frames) of >= 35% and a visible light transmittance (inc frames) >= 50%
  • Rooflights (uninstalled) should have a U value of <= 1.0 W/m2K
  • All habitable areas to have a glazing area (excl frames) >= 14% floor area
  • Typically space is heated with hot water coils within the MVHR ducts
  • MVHR should recover at least 75% of heat, with a fan using <=1.44W per l/s
  • Any non-solar water heating to be Gas Condensing boiler or CHP – wood fired stoves are not permitted (this conflicts with my peak-oil resilience planning)
  • Insulation on water tanks to be at least 100mm PU foam, all pipes and valves to be insulated with at least 40mm mineral fibre, and all cold pipes to have a vapour barrier
  • Lighting to be >= 50lm/W
  • Use the most efficient appliances – A/A+ minimum. TV to be LCD.
  • Use a heavy-duty membrane to air-proof the house.

In conclusion, this is a great list of targets which I may I don’t think I’d go for PassivHaus certification, even though I like the overall aims – my Peak-Oil resilience planning needs things that are proscribed by the standard – like a wood-fired stove!

 PassivHaus Resources

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