No rain, no high winds, so the EPDM can go on

After what feels like months, the forecast is for 2 days without rain or strong winds, so, at last, the waterproof EPDM membrane for the “flat” roof system can go on.

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Over the (checked for nail heads etc.) marine ply sheets is a protective layer (white below) and then the thick rubber EPDM  (ethylene propylene diene monomer) rubber sheet.
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The MVHR is due to start being installed tomorrow, so some of it’s ducting has arrived:

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Glass for the fish bowl has arrived

The Yprado GRP window frames and doors, with the glazing has arrived.

2014-01-23 10.45.50 (2) The rather large truck stayed down the road and the forklift cherry picker brought the pallets up to the house:

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The ecofab team are packing up areas that didn’t have panels with sheep wool (bundle below) and starting to put sealing tape for, what will be, an “airtight house”.

2014-01-22 08.57.23 (2) The rear external stair cast concrete steps are in:

2014-01-22 09.10.07 (2) From the beach, the house has it’s form:

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Dawn moon over the sea: 2014-01-19 08.06.33 (2)

 

 

 

Exhaust air into a hot water heat pump ?

I’ve been sent some info by Cernunnos Homes (“Renewable Energy specialists for the domestic & commercial sector.”) in praise of the  ESP Ecocent system. Peter one of the Cernunnos founders has put this into his own house:

If you not decided on a hot water system – take a look at the ESP Ecocent.

No RHI (exhaust air source is not considered green)

Can be integrated with RegaVent MVHR system (so in the summer the Ecocent can cool the house by recycling the air from which heat extracted back through the ventilation system).

When I got back to them about this meaning that the MVHR system isn’t re-directing captured warmth from air being expelled from the house to the cold air being pulled back into the house, they replied:

“…. normal MVHR is transfering heat out to  heat in.
However in the summer you want heat out and cold in, which is what the Ecocent delivers by cooling the air via the compressor.
In the winter we can either bypass (so extract and expel from the outside and leave the MVHR as a traditional system) however normally people either shower in the morning (before they go out to work), or in the evening (before they go out to socialise) or at end of night (when you want to let the temperature fall in the house). At these points (when the bathroom is over heated) the MVHR then kicks more heat back into the house when one would naturally be comfortable with it not recovering the heat to recycle to space heating, but there is a demand for water heating. So whilst either use (space or water) for the outgoing heat is an efficient use of that heat it can be argued that the water heating (with very low heat loss) is a slightly more efficient use of that heat! It is energy efficiency at the extremes, ie being efficient in the most efficient manner possible!

Pipework seals

I suspect these won’t work for any pipework to and from a fire (they’ll melt !)

The ATK Airtight Membrane Kit has been developed to provide an airtight seal around pipework of all types that passes through the walls of buildings. The ATK Airtight Membrane Kit can fit around any size pipe – from cables right through to soil pipes – and offers a robust, reliable and cost-effective solution.

http://www.greenbuildingstore.co.uk/page–pipework-seals.html

MVHR :: A Passivhaus perspective

Reading a Passivhaus article they have these as the key Mechanical Ventilation Heat Recovery (MVHR) reasons:

  • firstly its purpose is to provide sufficient fresh air,
  • secondly it is to avoid draughts and discomfort and
  • finally it is to reduce energy demand;
    – without heat recovery, ventilation leads to unnecessary energy demand and can cause thermal discomfort.

In buildings with MVHR, fresh air is drawn in through a heat exchanger, past the stale air being extracted from the building. The heat exchanger is designed so that the exhaust air warms the incoming outside air, before it finally leaves the building. Importantly the two air streams do not mix, thereby maintaining high standards of fresh air supply throughout the home.

In order to circulate the fresh air throughout the home, two low energy fans are used; one on the supply and one on the extract. The fans only consume a fraction of the energy that the system manages to ‘harvest’ from the stale air. Measurements have shown that they can save more than ten times the amount of energy that they use.

Opening doors and windows

  • You can open windows and doors. Yes, in winter, you’d impact the integrity and efficiency of the system if you leave doors and windows for long periods of time. But even in a non MVHR / Passivhaus building, this is unlikely to occur.
    And steam, smells etc. are being naturally extracted, so this “venting” requirement is no longer there.
    In warm weather, it’s good to open doors and windows of a MVHR / Passivhaus building. Especially at night to let in the cooler air, that you can day time keep trapped in the house at that temp.

Construction (embodied) Energy Vs Operational Energy

My Summary / Conclusion

  • In 2007, 16% of CO2 equiv impact is construction of a building, 84% is operational / in-use.
  • Today the split is roughly 20% embodied and 80% operational.
  • The modelling shows that we are moving to a CO2eq (CO2 equivalent) of 38/62% for masonry construction, and 35/65% for timber-frame construction.
  • No significant differences emerged between masonry and timber construction in terms of overall CO2 impact over the 60- and 120-year study periods. The largest difference observed between comparable masonry and timber constructions was 4%.
  • No clear / significant impact of thermal mass.
  • Emissions are cumulative, so 1 tonne of CO2 equiv at the point of construction roughly equals a tonne of CO2 equiv during the 60 year life of a building.

Which aspects of a dwelling are responsible for the largest CO2 impact?

  • Space and water heating have the largest CO2 impact in dwellings.
  • Appliances also have a large operational CO2 impact.
  • In both masonry and timber constructions, the impact of foundations and ground floors dominates the embodied CO2eq impact.
  • In masonry construction, the external walls also have a major impact.
  • Other elements, such as windows/doors and floor finishes, have a relatively large impact because they are repeatedly replaced throughout the life of the dwelling.
    • Waste water heat recovery systems have a 60 year assumed life span (windows and doors – 40, MVHR 15, flooring 10 ….)
  • The embodied impact of services was found to be approximately 5% of impact at 60 years and 7% at 120 years.

Construction Vs Operational Energy

I’ve come across some interesting figures and links to research in an article in the Green Building Magazine (by www.greenbuildingpress.co.uk).

  • Embodied Energy – a ticking time bomb (Spring 2012)

In 2007, around 16% of the CO2 equivalence impact was constructing a building.
– This covers the manufacture of materials and components, transport and construction.

84% of the CO2 equivalence impact of a building was down in use emissions.

This data is from http://www.bis.gov.uk/assets/biscore/business-sectors/docs/l/10-671-low-carbon-construction-igt-emerging-findings.pdf

That is why policy to date has been biased to making buildings more operationally efficient.

The article then makes the point that raises the importance of embodied (construction) emissions. Namely that since emissions are cumulative, 1 tonne of CO2 equivalence impact occurs for every year this “CO2” is in the atmosphere. So 1 tonne of CO2 at the start of a buildings 60 year life will have twice the impact of 1 tonne emitted during the building’s life.

The longer a tonne of CO2 hangs around in the atmosphere, the more damage it can do.

So it’s potentially dangerous to focus on carbon-intensive solutions that are installed at the point of construction, so that they reduce the operational emissions.

So, it is best to look for principles, materials, solutions etc. that will reduce both the construction (embodied) and operational energy of a building. So, as it’s often said, the general advice is still to optomise the fabric efficiency of a building before other measures.

October 2011 Update

The October 2011 report by the NHBC Foundation (“Housing Research in partnership with BRE Trust”) – Operational and embodied carbon in new build housing – A reappraisal:

Until now, focus has been almost entirely on the carbon emissions resulting from using homes, but clearly the balance between those operational carbon emissions and emissions from producing and installing the materials – the embodied carbon – needs to be considered.

This publication explores a subject which has to date lacked a strong and accessible evidence base. It looks at a range of carbon reduction scenarios as delivered through typical house types and estimates the likely impact both in terms of operational and embodied carbon – providing an insight into the contribution of different technical responses to the low carbon agenda, including the balance between operational and embodied carbon.

Evaluated Scenarios:

Twenty-four scenarios were appraised, using SAP software to determine operational CO2 emissions and BRE Global’s Environmental Profile methodology to analyse embodied CO2eq emissions.

The research considered the following variables:

  • two built forms (detached and mid-terraced)
  • two construction weights (masonry and timber frame)
  • three operational CO2 performance levels (25, 31 and 40% reductions over Part L1A 2010)
  • two dwelling lifespans (60- and 120-year study periods)
  • varying grid electricity CO2 intensity (to account for the expected impacts of grid decarbonisation).

Extracts from the report:

  • The modelling showed a typical percentage split between operational and embodied CO2eq (CO2 equivalent) of 62/38% for masonry construction, and 65/35% for timber-frame construction. These are averaged figures.
  • No significant differences emerged between masonry and timber construction in terms of overall CO2 impact over the 60- and 120-year study periods. The largest difference observed between comparable masonry and timber constructions was 4%.
  • The modelling showed that space and water heating, along with foundations, ground floors, windows/doors and floor coverings, were the largest contributors to overall lifetime CO2 impact. Appliances were also a significant contributor, but building designers have limited opportunity to reduce these emissions via their designs.
  • The typical split between operational and embodied CO2eq in new build housing has been taken as 80% operational, 20% embodied, a position largely confirmed by recent studies[1]. However, within the context of future Building Regulations requirements – which are expected to tighten to the point that new homes will be significantly lower in CO2 from 2016[2] – operational CO2 emissions are set to fall radically. This means that embodied CO2eq emissions will become increasingly significant in terms of the percentage they contribute to the overall CO2 impact of new build dwellings. In addition, typically the more energy efficient a given house type becomes, the greater the quantity of additional materials required to construct it (eg additional insulation, more services). There is also potential that such additional materials (eg renewable generation installations) may have particularly high embodied CO2eq levels. Both these considerations suggest that, as operational CO2 emissions reduce, embodied CO2eq emissions will increase.
  • The replacement of services and other building components has a direct bearing on both operational and embodied CO2eq emissions across the 60- and 120-year study periods.

Assumed lifespan of construction elements:

  • The proportion of embodied CO2eq in masonry construction was found to be higher than that in timber construction. However, this difference was relatively marginal, the maximum difference being 4%. This is because, other than the walls, the majority of building elements were similar in both the masonry and timber constructions modelled.

Which aspects of the dwelling are responsible for the largest CO2 impact?

  • Space and water heating have the largest CO2 impact in dwellings; this remains significant in all scenarios despite diminishing slightly as designs move from 25 to 40% CO2 reduction.
  • Appliances also have a large operational CO2 impact, although dwelling designers have limited ability to help achieve reductions in this area.
  • In both masonry and timber constructions, the impact of foundations and ground floors dominates the embodied CO2eq impact.
  • In masonry construction, the external walls also have a major impact.
  • Because both of these areas will last the lifetime of the dwelling, they should be considered at the design stage when seeking to reduce the overall dwelling CO2 impact.
  • Other elements, such as windows/doors and floor finishes, have a relatively large impact because they are repeatedly replaced throughout the life of the dwelling.
  • The embodied impact of services was found to be approximately 5% of impact at 60 years and 7% at 120 years. However, these results should be treated with caution as some aspects, such as controls, had to be omitted due to lack of available data, and the services were not studied in depth during this project.

Did the varying thermal mass levels have a significant impact on cooling?

  • No clear trend was identified from the modelling carried out, with minimal impact from space cooling in both masonry and timber designs.

Utility, shower and plant room

The idea is that in addition to a downstairs loo and room for shoes and coats, there will be a room for the washing machine, that also has in it a shower, sink, drying rack, and probably screened off, the “plant”.

The plant elements aren’t foliage etc. but the large bits of machinery for the house such as the hot water tank, Mechanical Ventilation with Heat Recovery (MVHR) unit etc.

So, not a lot more on this at the moment, but spotted this photo, that could be a start of this room. ie put the washing machine in a cupboard ?

Waikiki Chic contemporary bathroom

Components:

  • Washing machine
  • Shower
  • Hot water tank
  • MVHR unit
  • Sink
  • Drying area – potentially with a drip tray, as it will probably include wetsuits etc.

It’d make sense to look over the photos etc. for the coats, shoes etc. room.

Not a fan of this look and feel, but the storage looks good for the utility plant room.

traditional-laundry-room

The idea below of an over the washing machines hanging rail could work well. But there also needs to be some full height hanging for wetsuits to dry.

over the washing machines hanging rail

hand rail could be elsewhere:

hanging rail

Washer and dryer platforms. The laundry room below puts the washer and dryer on a pedestal. I’m not having a drying machine, but it might be good to put the washing machine on a slight pedestal.

washing machine raised

Utility room sink to rinse wetsuits etc.

Also some counter top space.

The plant utility room might have extra space for the recycling (there will be some in the kitchen units).

IMG_1335

Light and ventilation tunnel ?

With the stairs going from the floor of the house, to the top and being capped by a sky-light, and also a south facing window (or two) at the top of this “column”, I was reminded of the Potton Lighthouse, with it’s “wind catcher / light funnel”.

I’m wondering if these windows could be an automatic, intrinsic way that the house heats and cools itself down?

Below is a screen shot from a PDF about the Potton Lighthouse.