ABBE Level 3 Diploma in Domestic Green Deal Advice 8. Renewables & Microgeneration

Domestic GDA Training – 8. Renewables & Microgeneration 1Training Material © Stroma Certification 2013 | Version 1.1

ABBE Level 3 Diploma in Domestic Green Deal Advice8. Renewables & Microgeneration

① Heat Pumps

② Biomass & Biofuels

③ Solar Thermal

④ Solar PV

⑤ Wind Turbines

⑥ Micro CHP

Presented by


The Measures


Renewable Energy

Renewable energy is energy which comes from natural resources, naturally replenished. In its various forms, it derives directly from the sun, wind, water or from heat generated deep within the earth.

Included is:• Electricity and heat generated from solar• Wind• Ocean• Hydropower• Biomass• Geothermal resources• Biofuels • Hydrogen derived from renewable resources


Passive Solar Design

Passive solar design refers to the use of the sun’s energy for the heating and cooling of living spaces. In this approach, the building itself or some element of it takes advantage of natural energy characteristics in materials and air, created by exposure to the sun.

• Passive systems are simple, have few moving parts, and require minimal maintenance and require no mechanical systems.

• Passive design is practiced throughout the world and has been shown to produce buildings with low energy costs, reduced maintenance, and superior comfort.

Any design feature that maximises insulation and uses free solar gain will be most cost effective in reducing the energy bills of a building over its whole life span.


Passive Solar Design

Recognising Passive Design

Passive solar design can be recognised by a range of features such as:• Double or triple-glazed south-facing windows - which allow infrared

radiation to pass through - plus smaller north facing windows to minimise heat loss

• Light tubes which channel sunlight from an outside roof or wall into a room during the day

• Trombe walls – this is a natural design features which moves air warmed by free solar heat into a space using convection

• A double-glazed conservatory or a solarium. • In hotter months, conservatories can be shaded and naturally ventilated to

protect from excess heat and ultraviolet rays. By closing doors at sunset, heat loss is prevented from the main building, using well insulated doors or windows.

The need for dynamic simulation modelling put it outside the scope of SAP.


Heat Pumps - advice


Air Source Heat Pumps

Air source heat pumps absorb heat from the outside air. This heat can then be used to heat radiators, underfloor heating systems, or warm air convectors and hot water in your home.

An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside. It can get heat from the air even when the temperature is as low as --15° C. Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, air, or water is constantly being renewed naturally


Ground Source Heat Pumps

Ground source heat pumps use pipes which are buried in the garden to extract heat from the ground. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in the home.

A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe - called a ground loop - which is buried in the property’s garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year - even in the middle of winter.


expansion valve

from energy sourcecompressor

to energy sourcereturn from the heating system

to the heating system

con

den

ser

Heat Pump system

Horizontal Closed Ground Loop

Vertical Closed Ground Loop

Vertical Open Loop Closed Pond Loop

Heat Pumps


Changing to a Heat pump – air source

Do you have somewhere to put it? You'll need a place outside your home where a unit can be fitted to a wall or placed on the ground. It will need plenty of space around it to get a good flow of air. A sunny wall is ideal.

Is your home well insulated? Since air source heat pumps work best when producing heat at a lower temperature than traditional boilers, it's essential that your home is insulated and draught-proofed well for the heating system to be effective.

What fuel will you be replacing? The system will pay for itself much more quickly if it's replacing an electricity or coal heating system. Heat pumps may not be the best option for homes using mains gas.

What type of heat emitter will you use? Air source heat pumps can perform better with underfloor heating systems or warm air heating than with radiator-based systems because of the lower water temperatures

required.



Costs

Installing a typical system costs around £6,000 to £10,000. Running costs will vary depending on a number of factors - including the size of your home, and how well insulated it is, and what room temperatures you are aiming to achieve.

Earnings

You may be able to receive payments for the heat you generate using a heat pump through the government’s Renewable Heat Incentive (RHI). This scheme should be launched in Summer 2013.

For systems installed after 1 August 2011, you may be able to get help with the installation costs of a new air source heat pump through the Renewable Heat Premium Payment scheme.

http://www.energysavingtrust.org.uk/Generating-energy/Getting-money-back/Renewable-Heat-Incentive-RHI

http://www.energysavingtrust.org.uk/Generating-energy/Getting-money-back/Renewable-Heat-Premium-Payment-Phase-2


Changing to a Heat pump

Considerations need to be given when changing from a boiler to a heat pump.

Specialist calculations are required to determine fabric heat losses and heat emitter sizes.

Due to the lower flow temperature of heat pumps compared to boilers, existing radiators may be undersized.



Existing system Air source heat pump performing at 220%

Air source heat pump performing at 300%

Gas £/yearCO2/year

-£130-30kg

£110850kg

Electric £/yearCO2/year

£4004,410kg

£6505,230kg

oil £/yearCO2/year

£50830kg

£2901,660kg

Solid £/yearCO2/year

£504,610kg

£2905,430kg

A negative number means it could cost you more to run the heat pump than the system you are replacing


Changing to a Heat pump – ground source

Is a ground source heat pump suitable

It doesn't have to be particularly big, but the ground needs to be suitable for digging a trench or a borehole and accessible to digging machinery.

Normally the loop is laid flat or coiled in trenches about two metres deep, but if there is not enough space in your garden you can install a vertical loop down into the ground to a depth of up to 100 metres for a typical domestic home

Costs

Installing a typical system costs around £9,000 to £17,000. Running costs will depend on a number of factors - including the size of your home and how well insulated it is.


Changing to a Heat pump – ground source

Existing system Ground source heat pump performing at 250%

Ground source heat pump performing at 300%

Gas £/yearCO2

-£20400kg

£110850kg

Electric £/yearCO2

£5104,780kg

£6505,230kg

Oil £/yearCO2

£1601,200kg

£2901,660kg

Solid £/yearCO2

£1604,980kg

£2905,430kg


Heat Pumps – overview

• Could lower your fuel bills, especially if you replace conventional electric heating.

• Could provide an income through the government’s Renewable Heat Incentive (RHI).

• Could lower the home’s carbon emissions, depending on which fuel is being replaced.

• Don't need fuel deliveries.• Can heat a home and provide hot water.• Need little maintenance - they're called ‘fit and forget’ technology.• Lower heat output than conventional system• High installation cost• Works better with an insulated dwelling• Need space externally to fit the unit• Performs best with underfloor heating due to lower water temperatures


Biomass & Biofuels


Biomass

Wood-fuelled heating systems, also called biomass systems, burn wood to provide warmth in a single room or to power central heating and hot water boilers.


Solid Fuel

Biomass • Comes in various forms

• Wood logs• Wood chips• Wood pellets

• When biomass fuel is combusted is releases carbon dioxide, but no more than it absorbs whilst the tree grows. Biomass is therefore considered to be carbon neutral

• Wood pellets and wood chips can be used in biomass boilers.

• Wood logs are used in open and closed room heaters.


Costs

A pellet stove will cost around £4,300 including installation. Installing a new log stove will usually cost less than half this, including a new flue or chimney lining.

For boilers, an automatically fed pellet boiler for an average home costs around £11,500 including installation, flue, fuel store and VAT at 5%. Manually fed log boiler systems can be slightly cheaper.

Pellet costs depend mainly on the size and method of delivery. Buying a few bags at a time makes them expensive. If you have room for a large fuel store that will accept several tonnes of pellets at a time, delivered in bulk by tanker, you can keep the cost down to around £190 per tonne in most parts of the UK.

Logs can be cheaper than pellets, but costs depend on the wood suppliers in your local area, as they cost a lot to transport. If you have room to store more than a year’s worth of logs you can save money by buying unseasoned logs and letting them season for a year.


Biomass & Biofuel Boilers


Biomass

Advantages• Affordable heating fuel ( price varies)• low-carbon option ( considered carbon neutral)• Financial support• Variety in fuels ( logs, chips, pellets )• Theoretically inexhaustible fuel source

Disadvantages• Potential to run out of fuel• Flue/chimney will need sweeping regularly• Ash needs to be removed from the system periodically• Expensive installation cost• Storage of fuel is needed• Still an expensive source, in terms of producing the biomass• Not appropriate for all dwellings


Biomass and Biofuel

Biomass is normally considered a carbon neutral fuel, as the carbon dioxide emitted on burning has been (relatively) recently absorbed from the atmosphere by photosynthesis and no fossil fuel is involved.

The wood is seen as a by-product of other industries and the small quantity of energy for drying, sawing, pelleting and delivery are discounted.

Biomass from coppicing is likely to have some external energy inputs, for fertiliser, cutting, drying etc. and these may need to be considered in the future.


Biomass

• Savings in carbon dioxide emissions are very significant - around 7.5 tonnes a year when a wood-fuelled boiler replaces a solid (coal) fired system or electric storage heating.

• Financial savings are more variable.

Fuel replaced Expected saving Expected carbon dioxide saving

Electricity £630 a year 7.5 tonnes a year

Oil £270 a year 3.9 tonnes a year

LPG £790 a year 3.6 tonnes a year

Coal £270 a year 7.7 tonnes a year

Gas £90 a year 3.1 tonnes a year


Solar Thermal


Solar Thermal

What is solar thermal technology?

Solar thermal systems heat water using the energy from the sun, which can then be stored for use in domestic, public or commercial buildings.

How does it work?

A closed circuit of pipes, powered by a digitally controlled pump, transports the heated transfer fluid to a coil in the hot water cylinder, which then stores the heated water for later use.


Solar Thermal


Solar Thermal

Flat Plate Collectors

A flat-plate collector consists of an absorber, a transparent cover, a frame, and insulation. Usually an iron-poor solar safety glass is used as a transparent cover, as it transmits a great amount of the short-wave light spectrum.


Solar Thermal

Evacuated Tube collectors

In this type of vacuum collector, the absorber strip is located in an evacuated and pressure proof glass tube. The heat transfer fluid flows through the absorber directly in a U-tube or in counter-current in a tube-in-tube system. Several single tubes, serially interconnected, or tubes connected to each other via manifold, make up the solar collector. A heat pipe collector incorporates a special fluid which begins to vaporize even at low temperatures. The steam rises in the individual heat pipes and warms up the carrier fluid in the main pipe by means of a heat exchanger. The condensed liquid then flows back into the base of the heat pipe.


Solar Thermal

Costs, savings and earnings

The cost of installing a typical solar water heating system is around £4,800 (including VAT at 5%). Savings are moderate - the system could provide most of your hot water in the summer, but much less during colder weather.

Supplemented heating Saving per annum CO2 saving per annum

Gas £60 230kg

Electric £85 500kg


Solar Thermal

Earnings

You may be able to receive payments for the heat you generate from a solar water heating system through the government’s Renewable Heat Incentive. This scheme should be launched in Summer 2013.

From August 2011, you may be able to get help with the installation costs of a new solar water heating system through the Renewable Heat Premium Payment scheme

http://www.energysavingtrust.org.uk/Generating-energy/Getting-money-back/Renewable-Heat-Incentive-RHI


Solar Thermal – Installer Requirements

To get the most from a solar thermal system, just like solar PV, the collector is best sited on a roof facing from east through west, with south being optimal.

The roof structure would need to be in generally good condition( free from defects) and the roof covering intact.

The system would need to be compatible with the existing heating system and the solar thermal system sized appropriately to the heating system and the occupants of the property

The system will need a thermal storage to enable the heat to be exchanged. so combination boiler systems are not usually used in conjunction with a solar thermal system.

Panels would usually fall under permitted development.


Solar Thermal – Installer Requirements

Typical efficiencies for solar thermal will be around 60%, with the majority of the hot water generated in summer.

Solar thermal panels even operate in low light conditions (cloudy days) to good effect (1/3rd).

However in the UK you will always need an axillary heat source.

In installing solar thermal there would need to be a enough room for the cylinder.


Solar Thermal – Sizing

The general rule of thumb is half a solar thermal panel per person.

Various effects have a impact on the amount of heat the panels are able to produce, e.g.:

• Orientation• Over shading• Pitch• Location in country


Solar Thermal – Maintenance

Maintenance costs for solar water heating systems are generally very low.

Most solar water heating systems come with a five-year or ten-year warranty and require little maintenance.

In general you should keep an eye on your system to check that it is doing what it has been designed to do.

You should have your system checked more thoroughly by an accredited installer every 3-7 years to have the

• Pump checked; and • Anti-freeze topped up.


Solar PV


Solar PV

Solar PV panels utilise the sun’s energy and convert it into free, renewable electricity that you can use to power lighting systems and appliances in your home.

PV produces electricity by converting sunlight using the photoelectric effect.


Solar PV

Light (protons) literally ‘knocks’ electrons out of the semi-conducting material.

Most PV is made from Silicon.


Solar PV

This technology has been used since the late 50’s in the space industry to power satellites and since the 70’s in solar powered calculators.

The first solar powered satellite, launched in 1958, is still in service.


Solar PV

There are three types of silicon cells:

1. Monocrystalline2. Polycrystalline3. Amorphous

There are also hybrid PV cells combining a layer of amorphous silicon over a layer of monocrystalline (e.g. Sanyo).


Solar PV – Monocrystalline Cells

Monocrystalline cells are cut from a single crystal of silicon. Cylinders of silicon are sawn into very thin slices called wafers, the thickness of a human hair.

Due to the delicate and labour intensive manufacturing process these cells are the most expensive to make.

However, they are also the most efficient with a range of 15% to 18%.


Solar PV – Poly or Multicrystalline Cells

Poly or multicrystalline silicon cells are cut from a block of silicon that is made up of a large number of crystals. The cells are completely square unlike monocrystalline cells.

Due to the impurities between the crystals those cells are slightly less efficient, having a range of 14% - 15%. However they are cheaper to manufacture.


Solar PV – Amorphous cells

Amorphous cells are manufactured by placing a thick film of amorphous (non-crystalline) silicon onto a wide choice of surfaces. This is flexible and can be mounted onto a curved surface.

This is the cheapest form of silicon cell but also the least efficient at 6%-8%.

Although less efficient this type of panel may be more efficient in cloudy conditions, this is the type of cell that is used in small devices.


Solar PV – Operation

First the inverter transforms the electricity generated by the panel from direct current (DC) into alternative current (AC).

The electricity is then used as normal by the electrical appliances such as lights, computers, fridges etc.

When the systems produces more electricity than needed the power is sold back into the grid via an export meter.

However when the system doesn’t produce enough or no electricity (at night for example), the electricity is imported from the National Grid as normal.


Solar PV – Optimum Conditions

Unlike solar thermal, PV is much more susceptible to variation in performance based on light conditions, and the orientation and pitch of the panels.

The 3 factors have an effect on the amount of energy that the system is able to create.

Optimum conditions:• South facing • 30˚ pitch• Unshaded


Overshading

Overshading – extract from SAP


Orientation and Pitch


Overshading

Ideally no overshading should occur.

As cells are normally connected in string, a small amount of overshading will affect the whole panel or module.

The examples to the right show partial shading that can reduce the module efficiency by 50%.


Solar PV – Costs

Costs

The average domestic solar PV system is 3.5 to 4kWp and costs around £7,000 (including VAT at 5%), with the typical cost ranging from £5,500 to £9,500.

Costs have fallen significantly over the last year. They vary between installers and products, so we recommend getting quotes from at least three installers


Savings

A 3.5kWp system can generate around 3,000 kilowatt hours of electricity a year – about three quarters of a typical household's electricity needs. It will save over a tonne of carbon dioxide every year.

If your system is eligible for the Feed-In Tariff scheme it could generate savings and income of around £645 a year (based on a 3.5kWp solar PV system eligible for a generation tariff of 15.44p/kWh). You will get paid for both the electricity you generate and use, and what you don't use and export to the grid.

When applying for FITs you will need to show evidence of your property's Energy Performance Certificate and this will affect what tariff you can get.

http://www.energysavingtrust.org.uk/Generating-energy/Getting-money-back/Feed-In-Tariffs-scheme-FITs

http://www.energysavingtrust.org.uk/Generating-energy/Getting-money-back/Feed-In-Tariffs-scheme-FITs/Energy-Performance-Certificates-and-the-Feed-in-Tariff


Wind Turbines


Wind Turbines

The UK benefits from some of the highest average wind speeds in Europe, making it an ideal candidate for wind energy.

The technology now generates around 2.5% of the UK’s electricity and the proportion is increasing rapidly.

Between 2007 and 2009 the amount of electricity generated from wind power in the UK increased by over 75% and in 2010 accounted for 58% of all UK renewable electricity generation.


Wind Turbines

There are two main designs of wind turbine – those with a horizontal axis and those with a vertical axis.

Most turbines for homes have a horizontal axis whilst they can be mounted directly on a building, turbines mounted on free-standing towers or poles can be more effective at capturing the wind’s energy.


Wind Turbines

A typical 1kW building-mounted system costs approximately £2,000.

A typical 2.5kW pole mounted turbine costs approximately £15,000.

A typical 6 kW pole mounted system costs approximately £23,000.

Savings will depend on the turbine type size, local wind conditions, economies of scale and the cost of the electricity being replaced by using the wind turbine.

Rural or coastal dwellings can benefit more easily from wind energy as local wind conditions are often good.


Wind Turbines

Building mounted turbines are a new type of wind turbine designed to be installed directly onto a building. This avoids the costs involved in erected a freestanding tower and foundations. Designs of these systems vary between manufacturers and include both vertical and horizontal axis machines.

However, a building mounted turbine will not normally generate as much electricity as an equivalent pole or tower mounted machine. It may also add stress to your home’s building fabric due to increased weight and vibrations.

You should always seek specialist guidance before installing a building mounted turbine.


Micro Combined Heat and Power (CHP)


Micro-CHP

‘Micro-CHP’ stands for micro combined heat and power.

Heat your home and generate electricity at the same time with a micro-CHP unit.

This technology generates heat and electricity simultaneously, from the same energy source, in individual homes or buildings. The main output of a micro-CHP system is heat, with some electricity generation, at a typical ratio of about 6:1 for domestic appliances.


Micro-CHP

A typical domestic system will generate up to 1kW of electricity once warmed up: the amount of electricity generated over a year depends on how long the system is able to run. Any electricity generated and not used can be sold back to the grid.

It typically costs between £5,000 - £6,000 to have a Micro CHP boiler installed.


Micro-CHP - Advantages

• Electricity generation as a by-product of heat. When the micro-CHP is generating heat, the unit will also generate electricity to be used in your home (or exported).

• Carbon savings. By generating electricity on-site you could be saving carbon dioxide compared with using grid electricity and a standard heating boiler.

• Financial income. Micro-CHP is eligible for Feed-in Tariffs and you will earn 11.0p for each kWh of electricity generated by your system. You will also receive 3.2p for each kWh of electricity you export.

• Easy installation. For the householder, there is very little difference between a micro-CHP installation and a standard boiler. They are roughly the same size. However, the installer must be approved under the Microgeneration Certification Scheme.

• Servicing costs and maintenance are estimated to be similar to a standard boiler – although a specialist will be required.


Micro-CHP – Disadvantages

• Micro CHP is a relatively unproven technology.• Carbon savings in most smaller, newer domestic properties are insignificant.• Micro CHP is inefficient for short run cycles.• There is a high incidence of unreliability in currently installed units.• On average, 50% of electricity generated in domestic applications is

surplus. There is a current shortfall of available export reward tariffs for excess electricity directed to the grid.

• Current life expectancy of micro-CHP units is reported to be relatively low.• High installation costs.• Some CHP units are heavy – requiring solid flooring.• Current payback period is in excess of 20 years, but will reduce

along with increased production.


Questions?


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ABBE Level 3 Diploma in Domestic Green Deal Advice 8. Renewables & Microgeneration

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Transcript of ABBE Level 3 Diploma in Domestic Green Deal Advice 8. Renewables & Microgeneration