Green Roof & PV

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From the Winter 2012 copy of Green Building Magazine (volume 22, No3).

Two green roof studies. One, carried out in Berlin, where green roofs had been installed in the 1980’s. They varied the PV arrays to find the most efficient:

  • Over 5 years, PV panels over a green roof Vs a bitumen roof has 6% higher yields.
  • If over a green roof AND on a swivelling stand that tracks the sun, then 10% higher.

So green roofs boost PV productivity AND as they insulate the roof, they decrease the amount of energy needed for heating and cooling.

 

The second study looked at planting schemes. The most popular current choice is sedum, du to high resistance to draught. Sedum was compared to Stachys byzantian, Hedera hibernica and Bergenia corifolia.

Stachys byzantina (commonly known as Lamb’s Ear) outperformed the other species in terms of leaf surface cooling, cooling the substrate beneath it’s canopy and even the air above it’s canopy during short intervals over hottest periods, when soil moisture was not limited.

The conclusion was to not choose the best plants for a shallow substrate, but those that provide the best all round environmental performance, including bio diversity. This may involve deeper substrates and some form of irrigation.

Hot water heat recovery via the Thermal Store?

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Instead of, or in addition to a heat squirrel, how about sending the domestic hot water (DHW) waste via a coil in the thermal store?

It should be easy to have a thermostat that checks if hot water being “thrown away” is above the temperature of the lower section of the thermal store, and if so, sends the water through a heating coil in the thermal store, so it passes over some of it’s heat before it goes down the drain.

From www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8005

  • water leaving the shower head at 42 deg C will have cooled to around 37 deg C by the time it gets to the drain.
  • The 5 deg heat loss will already have been recovered to the house (assuming effective MVHR on the shower room exhaust).
  • The heat squirrel holds 120 litres of hot waste water, to pre-heat any incoming cold water that is heading to the heat store.
  • By holding the hot water, there is more time for the heat transfer to any incoming cold water, especially any that sits in the coil inside the heat squirrel.
  • Hopefully this 120 litres of water is regularly self flushing as “grey water very quickly turns manky when stored, even for short periods.”

Hot Tub Hot Water Heat Recovery

One key thing here, is my plan to have a log fired hot tub.

  • I’m looking at hot tubs that use logs to get the water up to temp and then keep the temp there.
  • BUT to accelerate getting it up to temp after it has been left a while, I want the option to top it up with hot water from the domestic hot water supply.
    • Reading elsewhere, hot tubs tend to run around 36° degrees.  Although friends with hot tubs say they tend to run theirs between 37° degrees and 39° degrees.
  • I also want the option of taking water from the hot tub, when it’s not going to be used for a while and sending this via a heat recovery option back to the heat store.
    • I accept that sending “lumps” of less than 120 litres at a time will optimise this in terms of giving the water time to transfer it’s heat to the heat store / cold water coming in to the house.

Thermal Store

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This is part grabbing historical Thermal Store notes to one page, and part adding new notes.

Click here for notes on Thermal storage – pros & cons.

Looking at the Akvaterm thermal stores (which can go up to 5,000 litres !!)

From www.stovesonline.co.uk/wood_burning_stoves/Akvaterm-Geo-Thermal-Stores.html:

  • have a stratification baffle plate about a third of the way down the tank. (see photo below). This can be optionally upgraded to an insulated baffle to further improve performance but the added benefit is not huge as it is very good already.
  • Once the water above the baffle has been heated to a high temperature by the heat pump (50ºC-60ºC) it then shifts to heating the bottom two thirds of the tank to a much lower temperature suitable for underfloor heating (around 40ºC).
  • OR if / when the heat pump is generating lower temp water (often more efficient COP) it only targets the bottom section.
  • larger than normal lower domestic hot water coil. This is to ensure that the incoming mains water picks up as much heat from the bottom of the tank which holds the ‘cheaper’ heat produced at a high C.O.P.

From www.ecoangus.co.uk/Akvaterm_Solar_Plus_Accumulator_Tanks.html:

The AKVAir Solar Plus is available from 300-2000 litres and is 3 bar pressure rated. The tank has 4 coils, two for solar input and two for domestic hot water (DHW) and is divided by a baffle plate, approximately 60% below and 40% above the baffle. Each section contains one solar and one DHW coil and all coils are positioned vertically.

The AKVAir Solar is available from 300-2000 litres and is 3 bar pressure rated. The tank has 3 coils, one for solar input and two for domestic hot water (DHW).

From www.accumulatortanks.co.uk/Solarplus.htm:

Akva Solar plus coils diagram Akva Solar diagram key

Akva Solar Plus coils + baffle plate   Akva Solar Plus coils

 

From www.akvaterm.fi/eng/Accumulators/AKVA_SOLAR.41.html:

akvasolarplus_460

 

From www.akvaterm.fi/eng/Accumulators/AKVA_GEO.206.html:

  • AKVA GEO is suited to all heat sources (others seem to be solar or something specific).
  • example layout:

akvageo_solar_kaavio_459

 

From www.navitron.org.uk/forum/index.php?topic=14183.0:

Heating System Schematic

Dual Cylinders?

From www.chelmerheating.co.uk/dual_cylinder_thermal_store_systems.html:

  • For larger domestic and commercial projects, our dedicated heating buffer cylinders are used in conjunction with our high-gain unvented cylinders to allow greater variation between heating and hot water demand.
  • The separate low-temperature heating buffer allows the small, infrequent heating demands of a property that is “up to temperature” to be met by stored renewable energy before activating the heat pump/boiler to reduce wasteful on/off cycling.

YPRADO GRP Windows and Doors

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This week, one of the senior chaps from YPRADO came to the ARCO2 / ecofab offices to do a presentation on the YPRADO company and their Pultec®  GRP Windows & Doors.

Great to see a full sample window and a corner cross section.

GRP goes under several names:
GRP = Glass Re-enforced Plastic = Fiberglass Reinforced Plastics (FRP) = composite

Great to have the presentation and then discussion with Chris Dixon from YPRADO and the ARCO2 / ecofab team.

  • Manufacture.
    • The GRP is pulled through the pulleys etc. The even and controlled drying out / curing of the GRP means that if damaged (like a GRP surf board) you don’t exposed glass fibres and un-cured resin that can give osmosis star crazing.
  • Maintenance needs (super low, just the metal hardware)
  • Lifespan (75 years plus, ease of replacing any glazing units that fail).
    • Outlasting PVC, Alu clad wood etc. means ends up being cheaper and lower environmental impact as one set of GRP windows and doors = 1+ sets if PVC, wood or Alu clad wood.
  • End of life recycling (theoretically possible, but nobody is currently doing this, but how much are Alu clad timber frames etc. properly recycled? Sadly, few if any).
    • In Europe their seem to be only 3 factories who can recycle GRP. ERCOM in Germany, MCR in France and Miljotek in Norway. They struggle to find markets for their recyclate.
    • Current end of GRP life is landfill (relatively cheap), incineration (50% becomes ash which is landfilled) or into cement production (energy from incineration and ash into the cement).
    • There is currently no market value for waste composite in the UK as recyclate. Other than a few firms which grind production waste and use it as filler. At the moment the recycling cost is too high. As the price of landfill goes up or the raw material price goes up, this could change.
  • Cost.
    • Outlasts alternatives, so over 30 years apparently cheaper than PVC.
    • Wood required re-painting every 3 or so years. Factor that cost in and the shorter life and more expensive.
    • Initial outlay can be lower. Current GRP quote from Pultec is a LOT less than the quote for Alu Clad wood doors and windows (that don’t have as good a thermal U-value !)

Photo of the sample window brought to the meeting. Focusing on the handle!

YPRADO - window handle

Pultec GRP Windows Specification

  • Triple glazed
  • Krypton fill
    • Argon has a thermal conductivity 67% that of air,
      krypton has about half the conductivity of argon.
    • Krypton is an inert gas, heavier and denser than Oxygen. It is colourless, odourless, tasteless and harmless. The Earth’s atmosphere is made up of approximately 0.00011% krypton. It is obtained by separating air into its constituent components by fractional distillation.
  • Warm edge spacers
  • Double Low ‘E’ softcoat.
    • This metal coating reflects heat (keeping heat in during the winter and sun heat out in the summer)
    • Soft coat Low E glass is more reflective than hard coat Low E glass.
    • Soft coat Low-E glass,  involves the application of silver, zinc or tin to glass in a vacuum. The glass enters a vacuum chamber filled with an inert gas which is electrically charged. The electricity combined with the vacuum allows molecules of metal to sputter onto the glass. The coating is fairly delicate or “soft.”
    • A “hard-coat” low-e application is done when the glass is in a molten state. The process results in a durable coating that can be used on storm doors and windows. A “soft-coat” low-e application happens after the glass is made. The soft coat is more efficient at reflecting heat energy, but also more delicate. This low-e coating always faces the insulating airspace in double or triple-pane glazing. Since soft coat emissivity can oxidize when exposed to air, argon or krypton gas is often used in the insulating airspace to help preserve the coating.

Summary of advantages of GRP Windows:

This summary is from an email from YPRADO.

Sustainability:

  • “A” Rated in BRE Green Guide to Specification for Sustainable Construction (UK)
  • BREEAM: 4½ extra credits potentially available.
  • 22% is from a recycled source. Product 100% recyclable upon disposal.
  • 65% glass content, (silica/sand, the most abundant substance on the planet)
  • Sensitivity Report (emailed to me), quantifying environmental credentials by sustainability consultants Price & Myers, London.

Energy Efficiency:

  • “U” values 0.8 – 1.6 “U” W/M2K on the total window. 1.2 U value achieved with double glazing only, no need for triple (thus cheaper and less wear on hinges)
    • I’ve asked for triple glazing, so even better U Values.
  • Low embodied energy in pultrusion manufacturing process (confirmed by GreenBuildingForum threads, where there was however some discussion regarding the embodied energy of the raw materials).

Durability:

  • Twice the strength to weight ratio of mild steel – cannot deform like aluminium
  • 75 years service life + 12 year Warranty.
  • Negligible coefficient of expansion, even if coated black
  • Performance unaffected in temperatures between +100C and -100C
  • Impervious to UV degradation
    • But the paint will slowly fade in colour.
    • The paint is over the white GRP frames. The paint chemically bonds to the GRP (unlike paint on Aluminium frames).
  • Impervious to salt corrosion and sea water.
  • Impervious to the harshest weather – effectively, indestructible by natural forces.

General performance:

  • Robust! – used on Young Mental Offenders Secure Units – Meets MOD anti-terrorist glazing requirements – DMG2 “Normal”
  • Secured by Design accredited – Police preferred specification – including both BS 7950 and PAS 23/24
  • Zero maintenance required – however, surface damage, structural repairs and re-painting can be easily undertaken on site, with no consequential liability for future applications.
    • You can just use surf board resin or similar.
  • High resistance to impact damage – will not deform under impact.
  • Highly price competitive with aluminium and timber/alu composite windows.
  • Any RAL colour available (200+ options)
  • Impervious to all chemicals and most acids.

An alternative Hot Tub

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I’ve thus far been considering a Dutch Tub hot tub:

  • I think they look cool
  • Their water volume is “only” about 650 litres, so not too much to heat up and keep walm. Also not too much weight.

BUT their size does mean while they are super comfy for 2 people, as soon as you go over that, it gets a bit of a squeeze. (the bottom of the Dutch Tub tubs domes up).
Look at these 2 pic’s of 1 and 2 people in a Dutch Tub (there is only one size). Click on either pic and you’ll get the full size version where yu can see toes at the other side of the tub and arm spans etc.

dutchtub-2_people  dutchtub-1_person

I’ve just found Cashen Hot Tubs. Their tubs are 100% made from timber from local (Cornish) forests. Mostly from Dutchy controlled forests less than 6 miles from their sawmill.

They come with a wood burner heating option that looks the same as the hot tubs I was in at last years (2012) Nova Festival:

Wood fuelled hot tub at Nova Festival 2012

 

The 1.7m diameter Cashen hot tub is down as suitable for 4-5 people. It’s about 400 kg empty, so add the 1,800 litres of water, the burning fire and a few people and you rapidly get to 2,500 kg or a bit more.

  • The inside depth of the tub is 920mm, outside height is 1090mm. They have said they can make a shallower tub to make the most of your sea view. But will that mean cold shoulders ?
  • They can also add a filtration system to the wood fired hot tubs.

Below are some photos and other info from the  Cashen Hot Tub Website and some emails from them (so accurate early 2013):

Wood Burner Hot Tubs (Elec heated a bit more £)
1.5m (4.5ft) dia. 1,600 litres seats 3-4 people £3,125
1.7m (5ft) dia. 1,800 litres seats 4-5 people £3,475
1.9m (6ft) dia. 2,500 litres seats 5-6 people £3,725

The tubs have an “inside depth of the tub is 920 mm, outside height is 1090 mm. If you were interested in a shallower tub to make the most of your sea view, this could be accommodated.”

Prices include our eco-friendly underwater wood-burning heater and integral seating as standard.

The stove is made from marine grade aluminium. They can be replaced at £800.

Hot Tub Optional Extras
Wooden Steps (I assume external to get in and out !) £195
Lift off wooden cover £265
Lift off custom made insulated cover £350
Pipe work screening
– which it looks like the Nova Festival tubs had. The Cashen photos below show tubs without a cover over the pipe work.		 £515
Filtration system £515
Stainless steel finish for chimney £180

Water Temp & Stove Size

Reading elsewhere, hot tubs tend to run around 36° degrees. The stove needs to be sized to not over or under heat the size of the tub.

Hot Tub Placement & Maintenance

The more they are not left the better.

“Use it and wash it regularly, another important thing is to make sure the is adequate air circulation underneath the tub. There is no problems using sea water in the tub as the stove is a manufactured of marine aluminium, the actual barrel itself works better with salt water as it keeps the moisture better and it slows down the dry out process.”

Photos from the Cashen Hot Tub Website:

cashen-hottubs-gallery-LP-08

 

cashen-hottubs-gallery-LP-01

 

cashen-hottubs-gallery-LP-017

 

cashen-hottubs-gallery-LP-02

 

From another Website:

wood fired hot tub - schematic

Mats

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In addition to the main front door having a flush inset door mat (see below), this probably also makes sense for the entrance to the boots & coats room

flush-inset-door-matt

 

flush-inset-door-matt-02

 

For general floor mats, these “eco mats” look good:

Eco barrier and door mats to keep your home clean and looking great. We’ve got fun door mats, mats for dogs, for keen gardeners and for doing your laundry. Super absorbent and durable, the mats get softer the more they’re washed and are made of 100% recycled materials by UK manufacturer Hug Rug.

 

 

Bamboo Flooring

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I have some samples from www.bambooflooringcompany.com.

Bamboo flooring is one of the hardest natural materials available for flooring and is an excellent alternative to hard wood flooring. Bamboo has a higher fibre rating than any hard wood, which gives it exceptional hard wearing qualities.

bamboo is a rapid growing grass and not wood, it can be harvested every 3-5 years, unlike 15-25 years for most wood. This makes bamboo a very environmentally friendly product for flooring.

BambooFlooringCompany - 01

 

Also get samples etc. from http://pandaflooring.co.uk/engineeredcrossplyclicklockbamboo.html

Thermal Scanner

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There are a lot of conversations on the GreenBuilding Forum:

That include using a thermal scanner for during and post build use of thermal scanners to check for thermal efficiency (leaks, bridging, U-values).

Wait for the heating to be working, so that it’s warmer inside than outside by 8C or more (so probably winter !) and start using a scanner.

From inside, to look in all directions (floor, walls, ceiling) and from as many external aspects as you can. You could find where (for example) insulation in the wall has perhaps sagged and left a less insulated section.

Yes you’ll possibly find problems when it’s too late (ie not during the build) but better late than never, as you may still be able to improve where these problems are.
– if it’s during the build, but post final hand over, you can get the builder(s) in to sort out the problems.

It’d also be interesting to 2, 3, 5, 10, 20 years on to do the same and see how the building has held up.
– yes it’d be good to also get an air test several years in.

Cost Implication / Problem

One problem with this plan is that an air test is about £300 at the moment. That’s a lot, unless you believe there is a big reduction in the building efficiency and you want to check, to confirm (and if the case) resolve what has failed over time.

FLIR Thermal Image cameras start at around £1,000 and what training / learning do you need to use one properly?

 

FLIR i3 / i5 / i7 camera model comparison

From http://www.flir.com/cs/emea/en/view/?id=42844

 FLIR i3 FLIR i5 FLIR i7
Thermal image quality:
60×60 pixels		 Thermal image quality:
100×100 pixels		 Thermal image quality:
140×140 pixels
Field of View:
12.5°(H) x 12.5°(V)		 Field of View:
21°(H) x 21°(V)		 Field of View:
29°(H) x 29°(V)
Center spot Center spot Spotmeter, area with max./min. temperature, isotherm above/below
Thermal sensitivity: 0.15°C Thermal sensitivity: 0.10°C Thermal sensitivity: 0.10°C

“Modern” kitchen elements

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From http://www.houzz.com/ideabooks/1393668

“Contemporary” typically means of the moment or current, the design of right now. “Modern” refers to a specific design style from the early to mid 20th century that broke with the traditional styles of the days before the Industrial Revolution.

When I think of modern kitchen designs, I think of frameless cabinets, sleek and simple hardware, strong horizontal lines and a lack of ornamentation, with the natural beauty of the materials shining through.

Looking at the Houzz page on Contemporary kitchens, I’m biased to their definition of “modern”.

Back to the Modern Kitchen look and feel:

Flat panel door style (aka slab-door)

modern-kitchen_flat panel doors

Full overlay door, ie the door overlays the cabinet box.

modern-kitchen_full overlay door

 

Lack of ornamentation. ie no patterned tile shapes or multiple materials with textures. So sleek hardware, full height glass splashback. No patterns or veining on coutertops.

Emphasis on horizontal lines.

The picture below is also from Houzz.  Long clean lines.
– but on the detail, I want the hob elements on the island, not the sink. It’s more social to cook around the hob and putting the sink on the back wall means dirty dishes and dishes that are drying are more out of sight.

contemporary-kitchen

 

The picture below is from the Remo Alabaster Linear Second Nature kitchen. They have Falmouth and Wadebridge offices.