PV panels, fire chimney & skylight

Lots of site progress in general, but the sudden jump of the Photovoltaic (PV) panels going on the rear roof and the chimney being put in today, are big visible items:

2014-04-01 15.35.29 (2)

 

The PV panels are east west orientated and relatively flat (not 45 degrees) to (hopefully) generate more electricity year round. eg low light as the sun gets up and sets in the east and west, diffuse light coming through cloud or other haze. When the sun is due south, it should be fairly high in the sky.

 

2014-04-01 15.33.30 (2) 2014-04-01 15.08.37 (2) 2014-04-01 15.08.18 (2) 2014-04-01 15.07.54 (2) 2014-04-01 15.03.20 (2)

 

The stairwell skylight is now in:

2014-03-28 09.07.01 (2)

The garage is getting close to being ready for its roof ! 2014-04-01 11.38.18 (2)

 

But it’s all about the view:

2014-03-27 09.00.19-2

Thermodynamic Panels :: Happy Irish Customers

The Irish firm LVP Renewables have been installing Thermodynamic Panel systems in Ireland for a while. Their site has a big list of happy Thermodynamic Panel customer testimonials including:

We are a family of six-two adults and four children ranging in age from 13 to 21 years …. Having now had the system in for 10 months we are delighted with it and there have been no problems to date. We are never in need of hot water as we have had a constant flow since the systems installation in October 2011

Their FAQ page has a few interesting items:

Does this system need a back-up heating system during the winter?

No, this is the only solar panel heating system that will provide you with 100% of your hot water. Also our cylinders come with a mini-emersion inside that can be turned on manually if needed. However if you would like to incorporate a back-up heating system there is a provision for a secondary heating coil in most of the systems we provide (call for specific information on tanks). If you decided that you wanted the secondary coil in the tank then we would advise you to put a manual leaver on the system and only use it if necessary.

What is the difference between an Energie Solar Panel System and Solar Tubes or Plates?

Unlike traditional solar panels (tubes and flat plates) the Energie system offers:

  • No unnecessary annual maintenance checks. In order to maintain the maximum efficiency of tubes and plates they must be serviced annually.
  • LVP panels are lightweight (weighing only 8kg) and roof structures do not need to be reinforced. Conventional solar panels are heavy-weighing anything from 40-300kg
  • Energie Solar Panels absorb heat from both sides unlike traditional panels which only capture radiation on one side
  • One Energie panel (80cmx200cm) will provide a family of up to 6 people with all of their hot water needs. With traditional solar a large amount of panels is needed to provide similar quantities of water
  • Energie panels need no back up from oil or gas. Other solar panels need an auxiliary energy source when the sun isn’t shining or when in high demand
Is the system provided with any device to treat bacteria such as Legionella?

Yes. In accordance with current legislation, it is provided with a circuit to rise the temperature up to 70 Degrees, which is manually activated and automatically disconnected

What happens if we install 2 panels on the roof?

The heating time will be reduced by half

Thermodynamic Panel Case Study :: Cork (Ireland) water and space heating

Their site also has case studies including one for a central heating and domestic hot water system in Cork (so SE Ireland).

Most are about water heating only (no heating) with positive comments.

The Cork water and space heating was for:

  • 235 sq m 2 storey stone cottage with a large extension that has:
    – 4 bedrooms, 3 bathroom (1 en suite), 1 kitchen, 2 sitting rooms, 1 large hallway, 1 utility.
    The Silver Spray property is 281 sq m (4 bedrooms ….
  • Radiators (not under floor heating)
    – average water temp to the radiator circuit 45 degrees C input, 35 degrees average return temp.
    – the radiators give the property a 1000 litre water buffer !
  • 300 litre water tank.
  • I can’t work out what the figures mean !

 

Green Roof & PV

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.

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.

Thermodynamic Panels & a heat store or heat recovery system

Looking at one of the Thermodynamic Panel system PDFs:

One set up has a thermal store (a tank that heats up, and your heating is delivered by coils that go into this store, heat up and take that hot water to where you want it), and a second, linked to a pool seems to have a form of heat recover system, in that the colder water from the pool is going back in the loop for re-heating via the Thermodynamic panels and the thermal store tank.

 

For the thermal store the Akvaterm thermal store water tanks looked good at the 2012 Eco Expo in London.

  •  The Akvaterm Akvantti thermal stores are oblong which could be a better shape for the plant room. It’s available as 1400lt, 2000lt or 2400lt volumes. The 1,400 litre unit is £3,757.00 + £85 carriage.

Akvantti-Accumulator-Heat-Store-Tanks-4

 

A chunk more information on the concept and benefits of a thermal store (and their version of one) at http://www.greenspec.co.uk/thermal-storage.php:

Thermal storage – pros & cons

+ Provides effective buffering
+ Reduces boiler cycling
+ Allows for integration with low temp heating systems eg underfloor
+ Adds mains pressure to hot showers
+ Provides potable hot water
+ The use of a heat exchanger means that in most cases, thermal stores can be integrated with existing pressurised boiler circuits
+ Requires much smaller cold water tank then standard vented systems
+ Thermal storage is recognised by NHER software
– Heat can be lost through inefficient heat exchangers
– Storage temperature will usually have to be 10 deg C higher than required DHW temperature
– Cannot be used with existing DHW power showers and pumps
– Expensive and unvented storage, very expensive
– Vented stores require a header tank to be located above the heating systems

Points to consider when specifying a Thermal Store

  • The design of the heating system should be matched to the calculated peak heat load.
  • When including solar heating, ensure that there is extra capacity within the store to accommodate fluctuations.
  • Where a biomass boiler is being used, consider sizing the store to provide for the heat capacity generated in a load / firing
  • Consider designing not only for short-term anticipated capacity but possible future extensions to the system.
  • Consider stratification of water temperatures within the store, particularly where low-grade heating is provided. Effective separation between the hot water at the top of the tank and the cooler water at the bottom, can increase the time between charges.
  • Ensure that there is adequate insulation to the store (100mm + PU foam)
  • Ensure that there is adequate pipework insulation

 

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?

Some updated Thermodynamic heating system info

I’ve come across the GreenServeUK website with new info on the Thermodynamic Panels.

There’s a big FAQ at http://www.greenserveuk.com/faq/

How it works from http://www.greenserveuk.com/thermodynamics/how-they-work/

Step One

The environmentally friendly refrigerant liquid is fed into the veins of the solar collector.

This refrigerant (R134A) has a boiling temperature of -25°C. The panel absorbs the heat from the environment and raises the temperature of the refrigerant.

The liquid absorbs the heat and it vaporises into a gas which increases the pressure.

Thermodynamic Panel Dimensions are h 800mm, l 2000mm, D 20m.
Each panel is about 8 kg.

Step Two

The hot gas is then passed through a compressor where the pressure causes it to heat further.

Step Three

The heated gas is then passed into the heat exchanger where the heat is transferred into the water cylinder.

Step Four

The cooling gas then passes through a valve reverting back into a liquid where it runs back into the panel where the process begins again.

The system is a solar domestic hot water system in which the solar loop operates on a similar principle of a heat pump.

It is composed of:-

  • An unglazed heat absorber  (1) with 3.20 m2 total aperture area.
  • An insulated,  hot water thermal store (200 l) (2)
  • A  thermoblock, which comprises the electrical powered compressor (5), the thermostatic expansion valve (7), the electrical heating element (4) and the controller.
  • Heat transfer fluid (refrigerant R134a)

The heat transfer fluid in the solar loop is the refrigerant R134a.

The refrigerant is passing through the absorber and evaporates while collecting energy from the surroundings.

The evaporated refrigerant is sucked by the compressor which raises the pressure.

In the condenser, which is integrated as an immersed solar-loop heat exchanger in the lower part of the store, the refrigerant condenses while transferring its condensing heat to the domestic water in the store.

Before the refrigerant is returning to the absorber, a thermostatic expansion valve is reducing the pressure.

An electrical heating element is located in the lower part of the store at the height of the solar-loop heat for use in emergencies and for the anti-legionnaires system.

The magnesium anode (8) or sacrificial anode will extend the life of the tank.

 

Thermodynamic installed at Maidstone UTD Football Club

Just got this press release:

Thermodynamic installed at Maidstone UTD FC…
Project: Maidstone United Football Club – Gallagher Stadium
Client: Graham
Contractor: Gallagher / Greenheat

Thermogroup UK recently supplied two Thermodynamic systems, an Eco 2000 and an SB 24 to meet 100% of the hot water demand for showers and underfloor heating at the new home of Maidstone United FC.

MUFC were attracted to Thermodynamic because of the environmental factor and the potential savings possible against the originally specified electric heating system.

Thermodynamic panels at maidstone united

 

It was estimated that a 24 panel system, to provide underfloor heating to the clubhouse, would use a minimum load of 4.2kW of electricity. Based on this figure and assuming the system is used for an average of 5 hours a day, it is estimated that the SB 24 at MUFC will cost £2.10 per day or £766 per year to run (at £0.10/kW per hour).

The SB24 at MUFC is expected to have a payback of around 5.5 years and bring about an annual saving of £3000 when compared to the electric system that was originally specified.

Please note: The figures in this email are estimates only and we are in the process of installing energy monitors at MUFC to track the exact running costs, savings and payback period.

Thanks for taking the time to read this email and look out for the next Hot News delivered to your inbox. Please consider adding this email address to your safe senders list to ensure you receive all of our communications.

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.

Solar Panel Feed In Tariff Update (FIT)

From http://www.building4change.com/page.jsp?id=1305

The tariff for a small domestic solar installation will be 16p per kilowatt hour, down from 21p, and will decrease on a three-month basis thereafter, with pauses if the market slows. All tariffs will continue to be index-linked in line with the retail price index (RPI) and the export tariff will be increased from 3.2p to 4.5p. The new tariffs are expected to give a return on investment (ROIs) of more than 6 percent for most installations, and up to 8 percent for the larger bands.

The scheme lifetime will be reduced from 25 years to 20 years for new solar installations.

FIT changes

  • Tariffs for solar PV installations from 1 August to be 16p/kWh for household scale solar PV installations. Tariffs for larger installations are also to be reduced
  • Multi installation tariff will be increased to 90 percent of standard tariff. Organisations with more than 25 PV installations will get 90 percent of the standard applicable tariff, increased from 80 percent
  • Average tariff reductions of 3.5 percent every three months. Reductions will be bigger (up to 28 percent) if there is rapid uptake.
  • Tariff cuts will be skipped (for up to two quarters) if uptake is low. Uptake in three different bands (domestic (size 0-10kW), small commercial (10-50kW) and large commercial (above 50kW and standalone installations) will determine the quarterly reductions within those bands.