Showing posts with label solar thermal. Show all posts
Showing posts with label solar thermal. Show all posts

Tuesday, 29 March 2011

Case Study: Penzance Project

Case Study: Penzance Project




These are six starter flats built on top of the old casino in Penzance. They are structural insulated panel construction. Stove Shop fitted one thirty tube solar thermal collector on each unit which runs a thermostore providing domestic hot water and three radiators via the solar collector and 3 kW immersion heater. These units were rated at Code 4.

PROS:
-          Doesn’t use oil or gas
-          Very economic to run
-          All future installations like this are applicable for renewable heat incentive
-          Automatic; no labour required
-          No servicing required
-          60% reduction in fuel costs compared to traditional fossil fuels

CONS:
-          No sunshine, no backup heat

FoFor more information on this case study or others, please call us on 01579 345018 or email sales@stoveshop.co.uk 

Tuesday, 8 March 2011

CASE STUDY: Welsh Farm Cottages

Neuadd Farm Cottages

A Baxi Solo Innova 50 wood boiler coupled with four solar manifolds with twenty two evacuated tubes each. Supplies heat to a 3000 litre cylinder, this heat store feeds a great main distributing to nine holiday cottages, each of which has underfloor heating a small radiator circuit and mains pressure hot water. There is an immersion heater in each cottage as backup. As this heated water is pumped round the cottages on demand, indicator lights in the boiler room show whether heating or hot water is being called for and from where.
Other provisions in the boiler room are; 
-          a high limit thermostat on the cylinder will circulate water round the heat main. This extra 200 litres is intended to cope with possible over production from the solar panels. It has a yellow indicator light on the control board.


-          A low limit thermostat on the cylinder which prevents any demand from switching on the pumps. This allows for faster heating recovery and has a yellow indicator light on the control board.
-          Within the control box there are three 6a. Circuit breakers. Two of them isolate the cottages and are in groups 1-4 and 5-9. The third isolates the boiler and its controls. This means that the boiler can be fired independently if needed or with just one group of cottages.


-        Within the control box there are two 2a circuit breakers which isolate the pump sets. Using these one or two can be selected to match the load of occupation or in the event of a breakdown, the faulty one switches off and the system will still function.


-          As mentioned above the demand from each cottage is indicated on the control panel. A blue light for DHW and red for heating and these show against the cottage number.
PROS:
-          Batch burns in intervals, meaning more cost effective
-          90% reduction of heating costs
-          Collar input reduced refuelling cycles on boiler

CONS:
-          Labour intensive
-          Large storage units required

GOOD FOR:
-          Rural farms, big estate houses
-          Large detached properties with acreage

FoFor more information on this case study or others, please call us on 01579 345018 or email sales@stoveshop.co.uk 

Thursday, 24 February 2011

CASE STUDY: Barn to Boiler Room

Barn to Boiler Room

A three bedroom cottage with two bathrooms has a remote boiler room connected to the house by a heat main. This supplies two radiator circuits and a mains pressure cylinder for domestic hot water.

The boiler is a Baxi solo Innova 30 which burns logs from the owner’s woodland. One charge per day heats a 1500 litre thermostore cylinder from which are drawn the heating needs of the cottage. This cylinder is also heated by solar panels installed later as a second phase. These are able to take the place of the boiler and also generate enough to meet the needs of the cottage. 



Where the heating flow is drawn from the top of the cylinder, a thermostatic valve governs the temperature of the water. This provision ensures the safety of the household and preserves the temperature within the thermostore.



In the cottage, programmable thermostats maintain separate temperatures for upstairs and downstairs by opening motorised valves which in turn start the pump to draw heat from the thermostore in the boiler room. Thus, in this installation, the solar panels provide heating for both domestic hot water and two radiator circuits.

PROS:
-          Solar panels preheat the thermostore and reduce batch burn time
-          During the summer the solar panels create more than enough hot water
CONS:
-          Labour intensive during the winter months
-          Needs a lot of space to store logs, house equipment
-          Needs a south facing roof
-          No automation
GOOD FOR:
Rural, detached medium sized house with outside storage.

For more information on this case study or others, please call us on 01579 345018 or email sales@stoveshop.co.uk 

Wednesday, 16 February 2011

CASE STUDY: Detached House with Detached Boiler Room

Detached House with a Detached Boiler Room

A Baxi multiheat 2.5 (25 kW output) wood pellet boiler, installed in an external boiler house, provides central heating and mains pressure domestic hot water to a four bedroom house with three bathrooms. There is also a thirty tube solar array which significantly contributes to both the domestic hot water and central heating.
At the heart of the system is a three hundred litre thermostore cylinder which is heated directly by the boiler and indirectly by the solar through a coil at the bottom of the cylinder. 



The domestic hot water is exchanged at the top of the cylinder and passes through a blend valve to control the temperature of delivery. 
Central heating is drawn from the middle of the cylinder and uses the system water directly to the radiator circuit and a in an auxiliary mains pressure cylinder for the bathrooms. The upstairs and downstairs radiator circuits are controlled by wireless programmable thermostats.

PROS:
-          Utilises garden shed
-          Semi automatic pellet burning boiler
-          Reduced fuel costs by 60% compared with oil
-          Solar input also reduced pellet costs

CONS:
-          No pellet store close to boiler, thus labour intensive
-          Need a large, dry area to store pellets

GOOD FOR:
-          Detached town house with large garden

FoFor more information on this case study or others, please call us on 01579 345018 or email sales@stoveshop.co.uk 

Wednesday, 2 February 2011

CASE STUDY: Solar Collector and Underfloor Heating

Case Study – Boscastle Cottage

There is a 16kW Fireview woodstove in the living room with an integral boiler which heats a 300 litre thermostore directly. This thermostore has a high efficiency coil to provide mains pressure hot water at 35 litres per minute.

Also in this thermostore is a coil for the solar collector which heats the cylinder directly as does the woodstove. It follows that either of these heat sources will provide domestic hot water and the solar  will contribute to the central heating even at times meeting the demand. A control panel on the upstairs landing displays the current activity and records the solar gain and kW hours.

Additional features of the cylinder are: a stratification plate positioned below the DHW coil which ensures a higher temperature at the top of the cylinder for hot water priority , a blend valve to govern the temperature of the DHW and two independently switched immersion heaters for backup if required.
The two zones of underfloor heating are controlled by Honeywell programmable room thermostats.
The upstairs radiator circuit has a Honeywell wireless electronic thermostat coupled to a twin channel timer, the second channel of which controls the towel rails.

PROS:
-          Underfloor heating has a large surface area so little energy is needed to power it.
-          All future installations of this nature are eligible for Renewable Heat Incentive

CONS:
-          Thermostores are large and heavy ; a reasonably secure first- floor space is needed
-          Thermostore has to be open vented due to solid fuel
-          Reliant upon the weather

GOOD FOR:
-          Second homes, as the underfloor heating automatically airs the house when no-one is there
-          New builds or renovations ; this system would easily allow a building to reach Code 3.

FoFor more information on this case study or others, please call us on 01579 345018 or email sales@stoveshop.co.uk

Tuesday, 16 November 2010

PV-T as featured on Channel 4's Grand Designs!

Stove Shop are proud to announce that we are the South West's only supplier and installer of the revolutionary new dual renewable energy system as recently seen on Channel 4's Grand Designs.



On their recent episode, Crossway; The Eco Arch, Grand Designs featured an innovative way of making solar panels as efficient as possible; PV-T panels. Kevin Mcloud, the show's presenter, recently wrote about the positives of such a product;

"Solar panels become less efficient as they get hot, but a new generation of units that produce electricity and hot water while keeping the panels cool could be the answer to higher efficiency, as Kevin Mcloud finds out
On average, every square metre of land on this planet soaks up about 250 watts of energy from the sun. On hot, sunny days it can be a kilowatt. On most days where I live in Somerset it’s zero watts. But just imagine if we could power, say, the whole of Europe using direct solar energy. Arnulf Jaeger-Waldau, a scientific officer and renewable energy expert at the European Commission’s Institute for Energy thinks we could; and at the Euroscience Open Forum in Barcelona last July he announced that capturing just 0.3 per cent of the sunlight falling on the Sahara and Middle Eastern deserts would do it.

It doesn’t sound like much, does it? And to do so would require a solar panel ‘farm’ about the size of Yorkshire. Except that if we covered Yorkshire in solar panels they’d produce just enough electricity to power a CCTV camera in Leeds. In the UK we urgently need fog panels. Meanwhile, the Arabs have another energy commodity they prefer to sell to us.

The Yorkshire/Sahara point is an important one, because getting electricity from the sun demands that you have some sun in the first place. Not surprisingly, Spain is one of the biggest investors and it has the two largest solar ‘power stations’ in the world, while countries like China and the USA are not far behind. In these places the payback on solar generated power is sensible. If you stick photovoltaic (PV) panels on your roof you’re likely to recoup the cost in a few years.



Here it’s more like half a century. Whereas if you choose to stick a solar thermal panel on your roof to do the rather mundane job of heating your hot water – by simply passing a fluid through some vacuum tubes or even just painting a radiator black and circulating your domestic hot water through it, you can recoup the cost (around £3,500) in seven to 15 years and you’ll even be pre-heating that water in winter. The general consensus is that solar PV panels (the ones that produce electricity) are expensive, but that installing solar thermal (for hot water) is a no-brainer.

Ten years ago I climbed to the top of Jodrell Bank radio telescope to look at the electronics at the very focus of that giant dish – the focus being the tip of the pointy bit in the middle. The dish bounces extraordinarily faint electromagnetic signals from the far edge of the universe and concentrates them at the focus, where a collector responds to these ethereal vibrations and turns them into exciting bleeps for astronomers to coo over.
The interesting thing for me was to discover that the electronics of the collector are kept at just below an unbelievably cool -272°C, a fraction of a degree off absolute zero, just to calm the electrons in the cables and circuits so that there is minimum interference from the electronics, and the intergalactic signals can be perceived.
My point? Electronics produce heat as they work (just think of your computer or laptop), but they’re only efficient when they’re running cool, when energy isn’t wasted as electrons and atoms bounce around. And the great irony is that photovoltaic panels only really get going and start earning their keep when the sun comes out. When it gets warm, in fact. The sun’s heat stimulates the electronics, which produce even more heat as they go to work, which immediately sticks the brakes on because the electronics start to become very inefficient. It’s the catch-22 in the world of silicon circuitry. But, ladies and gentlemen, this circular conundrum has just been solved.
For 170 years, since Antoine Henri Becquerel (French physicist and winner of the 1903 Nobel prize for discovering radioactivity) used selenium to experiment with photovoltaics in 1836, and for 242 years since Horace de Saussure, a Swiss aristocrat, naturalist and physicist, captured solar heat in his homemade solar box oven in 1767, the two disciplines have remained more or less separate.



Until a very short while ago when a team of brilliant German physicists had the idea of putting the two technologies together. At last. Their solution, one which I wish I’d thought of years ago, was to circulate the magic water from solar thermal panels around the electronics in solar photovoltaic panels. Bingo! Two benefits: hotter water quicker from busy electronics buzzing away and producing waste heat, and electronics which are cooled in the process. The result is the PV-T panel – as used by Richard Hawkes on his arched eco home– which produces 25 per cent greater electricity yields than a standard photovoltaic panel.

I’m still waiting for the third (or is the seventh?) generation of photovoltaic panels that are going to be printed onto my roof tiles or embedded into my scalp. The future of this extraordinary industry is rich with promise; a recent United Nations report revealed that solar power is attracting annual new investment of $33.5 billion dollars. And if you live in a drier, sunnier region of Britain, in East Anglia perhaps, or Bournemouth, you might want to consider this new hybrid panel.

Although the technology is so new it’s not yet accredited by the Low Carbon Buildings Programme, they are aware of its existence, so do check for any grants available towards installation (lowcarbonbuildings.org.uk). And once they’re fitted you can gloat about being able to sell energy back to your power supplier. The rest of us are, meanwhile, waiting for the first generation of fog-voltaic panels, or FVPs as I like to call them."

from 'Shine On', Kevin Mcloud, Published 02/07/09