Thermal Store

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.

Hot water heat recovery

What device(s) to put where to recapture as much of the heat from waste / grey water needs a decision.

The solutions from www.recoupenergysolutions.co.uk are clearly all very efficient and appear to be the same or similar to those that are well used in the US, where a lot of properties have their heating systems in the basement.

They are based on an “instant” transfer of the waste water heat to the mixer in the shower and also to the cold water feed to the water heating system.

BUT, the planned house will have clothes washing machines, a dishwasher and 2 showers on the ground floor. Being on the ground floor they wouldn’t work with all the recoupenergy solutions. Also a washing machine, dishwasher, bath (or hot tub) generates the waste water, some time after the hot water tank has been re-filled with mains cold water.

So in those circumstances, the www.esavep.com/products/hot-water-cylinders Heat Squirrel (scroll to the bottom) could be better and could provide a single (so a lot cheaper) whole house solution for all waste / grey hot water heat recovery. They are about £399 (not installed). The heat squirrel has a 120 litre capacity.

A key consideration / idea will be:

Can the waste water input be regulated so that only waste water that is warmer than the water in the heat squirrel is let in to it?

It seems that for a shower, the recoupenergy solutions will be the most efficient, but for the whole house, and the total cost, a single heat squirrel could be better than a heat squirrel and one or more recoupenergy solutions.

Heat Squirrel Schematic

Heat Squirrel - schematic
Heat Squirrel - installed

Some more Thermodynamic panel info

From a discussion on http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=9511&page=1#Item_15

Gary

I consider these as a form of air source heat pump, without a fan or finned coils. The underlying technology is well established and should be as reliable as a GSHP.

The panels are a good solution for a marine environment – I wouldn’t use ASHP units near the sea as the coils rot after about 7 years due to salt corrosion, so they would be a cheaper alternative than GSHP for such areas.

I have seen a completed installation and the owners were very happy with it.

Solar thermal it ain’t however – there is an improvement in COP when the sun is shining but it won’t provide free energy.

Chris

As far as I can find there are two manufacturers of these systems, the best known being Energie in Portugal http://www.energie.pt/ but also a company called Energy Panel in Spain. http://www.energypanel.es/productos.aspx?idFamilia=1&idProducto=1

The problem I have with them is a seeming lack of independent verification of their claims for running costs. I’ve seen mention of various installations being independently monitored but all my previous efforts to get these reports have so far failed.

Does anyone know of any such independent verification?

The UK is more energy efficient than it’s peers :-)

Good result for the UK.
– it seems we are doing the same, with less energy than other large economies 🙂

The UK has taken the top slot an energy efficiency ranking of 12 of the world’s largest economies. The American Council for an Energy-Efficient Economy (ACEEE) gave the UK the number one position in its first International Energy Efficiency Scorecard report.
It ranks 12 of the world’s largest economies across 27 metrics to evaluate how efficiently these economies use energy.

– http://www.aceee.org/research-report/e12a

The report shows there is, as you’d expect, plenty of scope to do better. But, for me, this is a great start.

Frame the sea view ?

How about, as suggested ages ago by Jo Brannan, reducing some of the north, sea facing glazing (glass windows, doors, panels) to have more of a frame on the view.

Yes it’s great to have some rooms where it’s full whack the view, where the end side walls, roof and floor are the frame.

But maybe some other rooms have less glazing. Walls are also much more thermally efficient and cheaper for the heating efficiency of the building.

This extreme framing (ie mostly wall Vs small window) works to amazing effect.

The above photo is from www.houzz.com

For this endless ocean view, instead of the windows going floor to ceiling, the designer chose to pull the focus tight by using a smaller window. The minimally framed window creates the look of art on the wall and brings your attention to the balance of sea and sky and the subtle gradient of color.

It seems almost any frame, can end up adding to the view:

A nice post about Accoya wood

http://blog.emap.com/footprint/2011/08/08/accoya-used-to-build-bridge-in-the-netherlands/

I’ve since learnt that (unless it’s changed and the info is out of date or wrong) that Accoya wood is grown in NZ & treated in the Netherlands. So the transport carbon footprint isn’t great. It’s then consequently expensive.

http://www.gowercroft.co.uk/2013/03/what-is-accoya-timber/

“The downside to this material is that while the trees are grown in New Zealand and the acetylisation process occurs in The Netherlands, it will always be expensive. The raw timber costs three times as much as our standard hardwoods.”

The geographic growing and processing isn’t mentioned on the Accoya website that does cover a lot of other good environmental aspects of Accoya:

http://www.accoya.com/sustainability/

Polar bear inspired external wall heating system

Follow the bears

The biomimicry-based technology imitates the effect of fur on polar bears, the individual hairs on the polar bear being hollow and guiding sunlight directly to the skin. As the polar bear’s skin is black, it is able to absorb light efficiently, and convert it into heat which it transfers to the body.

http://www.building4change.com/page.jsp?id=1339

External wall insulation system (EWIS) specialist Sto has brought its StoSolar solid wall heating system concept from Germany to the UK market.

The system incorporates a translucent glass render finish covering tiny capillaries that guide sunlight to a black absorbent layer, which converts solar to thermal energy. The masonry stores this heat and releases it back into the building as radiant heat, reducing the internal heating requirement.

Low sun means high heat

The amount of heat generated by the system depends on the angle of the sun. In summer, when the sun is high in the sky, less radiant energy is absorbed by the capillaries, so the heat generated is greatly reduced. In the winter, the low angle leads to the maximum amount of sunshine being transmitted to the absorbent layer ensuring that most heat is produced during the cold months.

StoSolar integrates into a Sto EWIS and is suitable for new and existing buildings when fixed to a solid wall that is not internally insulated. It will generally use 10-30 percent of a façade’s insulating surface area and be delivered to the construction site as prefabricated units to be incorporated into an external wall system.

Rooftop Hydroponic AND Fish Farm anybody ?

Treehugger.com had an article on this prototype system that combines hydroponics and a fish farm into one unit for all year round veggies and a few fish.

The prototype Globe/Hedron “is a bamboo greenhouse designed to organically grow fish and vegetables on top of generic flat roofs. The design is optimized for aquaponic farming techniques: the fish’s water nourishes the plants and plants clean the water for the fish,” according to designer Antonio.

Cornwall based sustainable furniture

I’ve got some ideas for a table made from recycled wood and maybe recycled steel. The more of the house (build, materials AND furniture) can be recycled:

  • Built in a way that can be recycled in the future
  • Be built from materials that have had a previous life

the better.

So great to come across St Austel based www.sustainable-furniture.co.uk who also have a showroom in Truro.

 

Saving energy and water :: Pipework

An interesting GreenBuildingForum.co.uk thread.

Long +/or copper pipes mean that the amount of water that needs to flow to a tap, before you have a hot tap can be a lot. Shorter plastic (that don’t absorb the heat, until they heat up) pipes will have a big impact on reducing the amount house users will run a tap in order to get their hot water needs / desires.

Also discussed is having thinner diameter pipework. If you have enough pressure, this means there is less water sitting in the pipes between times the hot water is requested. Suggestion is 12mm pipework.