6. Heating Systems v1.1

Report
Space Heating
Stroma – Heating Systems
© Stroma Development Ltd 2013 | Version 1.1
Heating in RdSAP
• RdSAP allows you to include:
– A main heating system (e.g. boiler)
– An additional main heating system, (2nd main system)
– A secondary heater (room heater)
• The additional heating system allows two main heating systems to be
included in the EPC. This means a wider variety of heating setups can be
specified in RdSAP.
• The secondary heating must be based on fixed room heaters
e.g. gas/ solid fuel fires, electric heaters
• it is not possible to select a central heating system as secondary heating.
Stroma – Heating Systems
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Main heating
• The main heating system is defined as:
– A system which heats the largest proportion of the dwelling
– A system which is not usually based on individual room heaters (although it can be)
– A system which usually also provides the water heating
• A typical main heating system would be a central heating boiler
• If there is more than one heating system or device in a property use the
following process to decide which is the main heating system
– The main system usually provides both space and water heating and should
heat at least 30% of the dwelling
– If no system provides space and water heating then select the system which
heats the greatest part of the dwelling
– If there is still doubt then select the system which supplies useful heat to the
dwelling at the lowest cost
– If the costs are the same then select the system which heats
the living room
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Additional main system
If a dwelling has an additional main system then the proportion of the property
heated by each system should be calculated. This should be based on heated floor
area to the nearest 10%
– If two systems serve the same heating circuit then assume there is a 50/50 split
– The main system should be the one which heats the living area
•
Examples where an additional main system can be used
– A large property has two different boilers fitted so the whole property can be heated.
One boiler is the main system the other is the additional main system.
– A property has a boiler fitted to replace storage heaters, but some functioning storage
heaters are left in the property, the boiler is the main system and the storage heaters
are the additional system
Previously only one main heating system could be entered, which restricted
RdSAP and meant some properties could not be accurately modelled.
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Secondary heating
• Secondary heating must be based on fixed room heaters.
– A fixed room heater is an independent heater not on a central system, such as a gas fire
or electric panel heater. The heater must be fixed in place, so portable heaters are not
included in the assessment.
• This means it is only possible to select the following
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Oil room heaters
Electric room heaters
Solid fuel room heaters
Gas room heaters
If there is more than one secondary heater in a property then use the following
process to identify the heater which should be selected:
1. Select the type of heater which heats the greatest number of habitable rooms
2. If that does not resolve the choice then select the heater which is cheapest to run,
based on fuel cost
3. If that still does not narrow it down, select the device with the
lowest efficiency
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Secondary heating
•
Portable heaters can be specified in particular circumstances:
– When the main heating system is an off-peak storage system (this is covered later
in this section) and no other type of secondary heating is present
•
The software will automatically include portable heaters in the EPC in
particular circumstances:
– If the main heating system is not deemed sufficient to heat a dwelling, and no
secondary heating is specified.
– If there is no heating system present in the dwelling at all
•
Portable heaters are defined as
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Completely free-standing and self-supporting
Contains a built in fuel store, or for electric heaters, has a lead and plug
Can be easily moved between rooms
Focal point electric fires designed for the located in a fireplace can be included in
the assessment as a fixed heater
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Main Heating Types
• Central heating systems
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Gas boilers
Oil boilers
Range cookers
Solid fuel boilers
Electric boilers
Heat pumps
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Community heating
Electric storage heating
Electric underfloor heating
Warm air systems
Room heaters
Stroma – Heating Systems
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Types of boiler
The most common type of boiler you will encounter will be
Mains Gas as is it the most widely available fuel.
The boilers will either
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Regular boiler
Back boiler
Combi boiler
Condensing boiler
Combined Primary Storage Unit
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What does a regular heating system
look like
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Hot water tank
Cold water tank
Feed and expansion tank
Expansion pipe- heating
Expansion pipe – hot water
tank
• Pump
• Programmer
• Room thermostat
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Regular Boiler
Key features of a regular boiler
– It can provide heating and hot
water for a dwelling
– The hot water must be stored
in a cylinder
– There are usually 3 pipes
coming out of a regular boiler,
gas supply, flow and return)
– The boiler heats water which
then flows around the
heating system and to the hot
water tank
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Back Boiler
• A back boiler is a type of
regular boiler, these are
fitted behind a fire.
• It provides space heating
and hot water.
• As with a regular boiler the
water is stored in a
cylinder.
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Back Boilers
• Back boilers can be
– Gas,
– solid fuel
– Oil
• In RdSAP gas and solid fuel back
boilers can be identified as
central heating systems
• Gas and solid fuel back boilers are
sometimes listed in the PCDF but
not always
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Identifying a back boiler
• How can you tell if a gas fire has a
back boiler?
– Look for a plate at the bottom
of the fire, this may come
away to reveal the boiler
controls
– Back boilers are usually more
substantial than a normal gas
fire
– There will usually be a control
dial, sometimes with the
boiler name on it
– There may be a cylinder with
no boiler unit
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Solid Fuel Back Boiler
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Combi Boiler
• A combi or combination boiler
provides heating in the same way
a regular boiler does
• It provides domestic hot water on
demand, rather than storing it in
a cylinder.
• A combi boiler is easily identified
as it usually has 5, 6 or 7 pipes.
• Combi boilers also have more
controls on the front of them e.g.
heating, hot water and sometime
a programmer
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Combi Boiler pipework
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What does a Combi Boiler system
look like
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Condensing Boiler
• A condensing boiler is a highly efficient type of boiler
• Most non-condensing boilers emit hot combustion gases, but a condensing
boiler extracts the heat from the combustion gases before they are
emitted, pre-warming the water in the boiler.
• This means the flue gases emitted are a lower temperature
• There is some condensation of flue gases as they leave the boiler, these are
drained out of the boiler through a plastic condensate pipe. This is the key
identifying feature of most condensing boilers
• Because the flue gases are cooler a plastic flue can be used, rather than a
metal flue
• On a cold day you may be able to see a plume of water vapour coming
from the flue.
Stroma – Heating Systems
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Condensing Boiler pipework
A. Central Heating Flow
B. Domestic Hot Water
C. Gas In
D. Mains Cold In
E. Central Heating Return
F. Overflow/ Pressure Relieve Valve
G. Condensate Pipe
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Condensing Boiler
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Condensing Boiler- Flue and
Condensate Pipe
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Combined Primary Storage Unit
• This is an appliance which incorporates the provision of space
heating and hot water; the hot water store should be at least
70L and integral to the appliance.
• This type of appliance is usually floor mounted and larger than a
conventional boiler
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Underfloor Heating
• Underfloor heating can be fitted to a boiler if it is fitted there will be a
manifold such as the one pictured.
• This manifold distributes the hot water amongst the underfloor heating loops
• If both underfloor heating and radiators are present in a property it is not
possible to include both as the heat emitter. Radiators should be specified as
they require a higher flow temperature, making them the worst case
scenario
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Underfloor Heating System
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Underfloor Heating System Layout
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Underfloor Heating – Floor
Construction
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PCDF
• Product Characteristic Data File
• The PCDF is a searchable database which includes the following types of
heating systems
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Gas and oil boilers
MicroCHP*
Heat Pumps *
Solid fuel boilers *
• The PCDF contains specific technical details about heating devices,
including their seasonal efficiency
• RdSAP software incorporates the PCDF when searching for heating
systems
* Covered later in this section
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PCDF
• Make sure you collect the device make and model information so you can
accurately identify it in the PCDF.
• If a device cannot be found in the PCDF then there is a list of types of
heating systems in RdSAP, the device should be selected from this
generic list, known as the alternative method in Stroma’s
software.
Stroma – Heating Systems
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Boiler ID Plate
The boiler ID plate is a very useful way of finding out all the information needed
to find the specific boiler in the PCDF
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Flue Types
• The flue can help identify the boiler type and it’s location.
• There are a 3 flue types
– Open flue
– Balanced flue
– Fan assisted flue
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Open Flue
• Open flues are usually found with older, floor mounted boilers
• The combustion gases are taken from within the room the boiler is in.
• The combustion gases are drawn up from the boiler by wind passing over
the top of the flue
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Open Flue
This is the more common type of open flue, these are found on
the top of converted chimneys.
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Open Flue
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Balanced Flue
• This type of flue uses air from outside the dwelling for combustion.
• It relies on natural air movement to draw the hot air back outside from the
boiler
• The flue must be located as close to the boiler as possible to keep the flue
length short
• A balanced flue is classed as ‘room sealed’
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Balanced Flues
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Fan assisted flue
• This is a room sealed flue which uses a fan to assist the movement of the air
through the flue
• This means the flue doesn’t have to rely on natural air movement and can
be located further from the boiler
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Fanned Flue for Regular Boiler
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Plastic Fanned Flue
• A plastic fanned flue indicates that the boiler fitted must be condensing
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Flue Gas Heat Recovery
Flue Gas Heat Recovery Systems (FGHRS) are designed to recover heat in the flue
gases discharged from a condensing boiler.
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•
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The boiler can be fired by natural gas, LPG or oil.
They use the cold temperature of the domestic cold water supply to recover extra
heat that is not extracted by the boiler.
This recovered heat is used to heat the hot water supply in two principle ways:
– Instantly – Recovered heat is immediately used to pre-heat to the domestic
water supply before it enters the boiler or external hot water cylinder.
– Deferred – Heat recovered during space heating production is stored for later
use to pre-heat the domestic water supply before it enters the boiler or
external hot water cylinder the next time hot water is required
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Flue Gas Heat Recovery
• FGHRS can either be integral to the boiler or separate from the boiler.
• An integral system is known as a Passive Flue Gas Heat Recovery Device
(PFGHRD), and selecting the correct boiler from the PCDF database will
include the heat recovery system in the calculation
• FGHRS can be fitted to existing boilers, in which case the system will be
separate from the boiler
• The FGHRS should be visible above the boiler, where the flue outlet is
located.
• In order to include the FGHRS it must be in the PCDF
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Flue Gas heat Recovery
A flue gas heat recovery system will
normally be found just above the
boiler unit.
Remember that the system must be
included in the database in order to
be included in the assessment
Stroma – Heating Systems
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Flue Gas Heat Recovery - Software
Select whether a
FGHRS is present
Select the fuel
type
Then select the FGHRS make
and model information
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Flue Gas Heat Recovery
Record the standard PV
data, kWp, tilt, orientation
and overshading
• A FGHRS can be fitted to a separate hot water store
• If this is the case it may be powered by PV
• Make sure you check for a solar PV array installed specifically to power the
FGHRS
• There is a section in the software for FGHRS and a PV array
specific to it
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Flue Gas Heat Recovery
RdSAP Convention 9.06 states:
– Include [FGHRS] only if found in database, identified in same way as
for heating systems. When the model cannot be found no default
option is available but the presence of the device should be recorded
in site notes
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Electric Central Heating
• Provides heating and hot water
• Generally for smaller properties such as flats
• No flue
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Electric Central Heating
• This is an electric direct acting
boiler
• The unit is about 1metre long and
can provide heating and hot
water, if a cylinder is fitted
• Common examples of this type of
boiler are the Heatrae Sadia
Amptec and the Trianco Aztec
Classis
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Electric central heating
• This is an electric water storage
boiler
• It uses cheap rate electricity over
night to heat water for space and
water heating
• There is a water cylinder within
the unit
• The cylinder must be less than
270L, if it is bigger the device is
classed as a Electric CPSU
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Electric central heating
• Electric CPSU – like a gas CPSU this
device has a hot water tank within the
device
• The water store must be over 270L for
it to be classed as a CPSU, otherwise it
is an Electric water storage boiler
• These units are generally quite large,
around 1.8m tall so will be found in
cupboards.
Electric CPSU
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Electric central heating
• Electric dry core storage boiler ;
this works in a similar way to
storage heaters, using cheap
rate electricity to heat bricks
inside the unit
• The heat is transferred from the
bricks to water via a heat
exchanger to provide space and
water heating
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Solid Fuel Boiler
• These can be either manual or
auto (gravity) feed
• Solid fuel boilers run on
traditional solid fuels such as
anthracite, or they can run on
biofuels such as wood pellets
• Solid fuel boilers are usually
regular boilers capable of
providing heating and hot water
for a property.
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Range Cookers
• To be accounted for as a heating system a range cooker must incorporate a
boiler capable of providing space heating
• Range cookers can run on solid fuel, gas or oil
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Range Cookers
• Gas and oil range cookers can either be
– Twin burner – has two burners one for heating and one for cooking
– Single burner – one burner which does heating and cooking
• If the range cooker is just supplying hot water it can be specified in the
RdSAP software. This will be covered in more detail in the water
heating section.
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Warm Air System – Gas Fired
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Warm air systems blow warm air out of vents located around the property
The main unit is floor mounted and about 1.5-2m tall
Warm air systems can run on gas, oil or electricity
Electric warm air systems use off peak electricity to store heat
overnight, so the property should have a dual rate electricity
meter
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Warm Air – Typical Vent
Extra care should be taken when looking for the vents, many can be
hidden behind wardrobes, sofas etc.
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Electric Storage Heaters
• Storage heaters use cheap rate electricity over night to store up heat in bricks
within the heaters. This heat is then released during the day
• Storage heaters make use of off-peak/economy 7 electricity which is sold at a
much cheaper rate
• Storage heaters use drift heat, and are often placed in
hallways and landings, as well as the main living area
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Inside of Storage Heater
Ceramic plates
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Old (large volume) storage heaters
• Old storage heaters are usually quite large, around 20-25cm deep
• They sit directly on the floor due to the weight of the bricks inside the
heater
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Modern Slimline Storage Heater
• Modern storage heaters are narrower, around 10-15cm
• They are sometimes attached to the wall with small feel to support their
weight
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Modern Fan Assisted Storage
Heater
• Some more modern storage heaters are fan assisted to improve the
distribution of heat from the device,
• These heaters have additional vents at the bottom and two separate wires
coming from the device, one for the peak rate meter, for the fan,
and the other to the off peak meter, for the over-night charging
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Integrated storage and direct
acting
• These storage heaters have a direct acting panel heaters integrated into
the device.
• This means the device is capable of providing on-demand heat as well as
the release of stored heat
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Storage heating
• When certain types of storage heaters are the main heating a secondary
system should be specified.
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Old (large volume) storage heaters
Modern (slim line) storage heaters
Fan storage heaters
Electric underfloor – in concrete slab
• Because integrated storage heaters and integrated underfloor heating
have direct acting heaters included in the device there is no need to
specify any secondary heating
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Electric underfloor heating
• In concrete slab (off-peak)
– This system uses the floor to store heat, much like storage heaters use the bricks
– There should be a dual electricity tariff available to the property
• In screed above insulation (standard tariff)
– Cables are laid just under the floor surface and provide on-demand heat.
– This system uses peal rate electricity and is often installed in one
room, usually a bathroom or kitchen)
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Electric underfloor heating
Integrated (storage and direct acting)
– This system combines the off-peak and on-peak systems
– Two sets of cables are laid in the floor, one placed lower than the other to
provide the off-peak heating
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Electric ceiling heaters
• This form of heating is very unusual in domestic properties.
• It was most commonly fitted in the 1970s and 1980s.
• It works in a similar way to underfloor heating, with panels embedded in
the ceiling construction, with insulation fitted above.
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Heat pumps
Heat pumps are becoming increasingly common in the UK
• They can be used as part of a wet central heating system or a warm air
system
• Heat pumps work by extracting heat from a low temperature source and
increasing the temperature so it can be used for heating.
• This results in greater than 100% efficiency as the amount of energy used
is less than the heat energy generated
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Ground Source Heat Pumps
A ground source heat pump is a device for converting
energy in the form of low level heat to heat at a usable
temperature.
• The heat pump consists of three main parts;
- ground collector loop,
- compressor,
- condenser heat exchanger
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Ground Source Heat Pump
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Ground Source Heat Pump
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Air Source Heat Pumps
Operating in a similar way to Ground Source Heat Pumps, Air Source Heat
Pumps are an alternative way of extracting useful thermal energy from
the air if ground space is not available.
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Community heating
Community heating is a system which provides heat to more than one
dwelling
• Typically community heating would be available in a block of flats
• The system in place would be a large industrial size boiler system housed
in a boiler room
• It is unusual to get access to the boiler room, but the system can usually
be identified by the lack of a boiler in the dwelling, but a wet heating
system is present.
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Community heating
• Three types of community system are available in RdSAP
– Community boilers only: a standard heating system which can provide
space and water heating
– Community CHP and boilers: a more complex system which includes
Combined Heat and Power. You must have evidence this is present to
include in the survey. (more details in the next few slides)
– Community heat pumps – large heat pump system which runs on
electricity, often a warm air system with vents visible in the dwelling.
Fan-coils can be selected as an emitter for community heat pumps
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Community heating
• Try and determine the fuel type of the community heating system, if this is
not possible assume the fuel is Mains gas.
• Additional fuel types are available to community heating as well as the
standard fuels such as mains gas and oil
– B30D – a form of biofuel made up of 30% bio diesel and 70% oil
– Waste combustion – heat produced at incinerators and similar waste
disposal sites can
– Biomass
– Biogas – landfill and sewage gas
• If community heating provides hot water only and the space heating
comes from an alternative source, such as electric panel heaters, then the
community heating can be specified as the water heating.
• Further details on this are covered in the Water Heating slides.
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Combined Heat and Power (CHP)
Bristol City Council
Community Heating
• When electricity is generated in central power stations around 60-65% of
the primary energy is rejected as waste heat into the atmosphere.
• Combined heat and power units generate electricity locally so that waste
heat can be used for beneficial purposes for heating or hot water.
• Where all waste heat generated can be used, CHP units will have overall
efficiencies of up to 80-85% compared to 35-40% for conventional power
stations.
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Combined Heat and Power Systems
• CHP systems produce roughly twice as much waste heat as they generate
electricity. To be viable and economic, CHP require a large constant demand
for heat.
• Current insulation standards mean the requirement for space heating is very
low and demand is present only part of the year. The only constant source of
heat demand is for domestic hot water and in terms of reducing CO2
emissions some of the demand could be met by the use of solar water
heating instead.
• For large CHP systems to be economically viable they need to run for at least
4,000 hours per year. They are most suited to leisure centres with swimming
pools and hospitals
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MicroCHP
Micro Combined Heat and Power
units are systems designed on a
smaller scale than standard CHP
• Micro CHP mainly generates heat,
with some electricity generation
• If the electricity is not used in the
home it can be sold back
to the grid
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MicroCHP
• Most micro CHP systems run on mains gas or LPG
• The latest micro CHP devices are similar in size to a domestic boiler
• Some micro CHP systems are now listed on the PCDF. If they cannot be
found on the database they should be listed as a condensing boiler used
the alternative method.
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Secondary Heating
Room Heaters
Gas fired
Solid fuel
Electric
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Secondary Heating
• Room heaters can be specified as the main heating system or a secondary
heater
• Only room heaters can be specified as secondary heaters
• Room heaters should not be specified as the main system or additional
system unless the only heating in the dwelling is from room heaters
• Room heaters are not listed in the PCDF, so they have to be entered into
the software using the alternative method
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Gas Fires
There are a range of gas fire options in RdSAP
The options available have descriptive titles which can be used to help
identify the type of gas fire you have
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Gas Fires
Selecting the correct gas fire is important as the efficiencies vary between
the appliances
– Gas fire, open flue, pre-1980 (open fronted) with or without back boiler
– Gas fire, open flue, 1980 or later (open fronted), sitting proud of and sealed to
fireplace opening, with or without back boiler unit
– Flush fitting live fuel effect gas fire (open fronted), sealed to fireplace opening,
with or without back boiler unit
– Flush fitting live fuel effect gas fire (open fronted), fan-assisted, sealed to
fireplace opening.
– Gas fire or wall heater, balanced flue
– Gas fire, closed fronted, fan assisted
– Condensing gas fire
– Decorative fuel effect gas fire, open to chimney
– Flueless gas fire, secondary heating only
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Gas Fires
Gas fire, open flue, pre-1980 (open fronted) with or without back boiler
– An older style of gas fire, often with the ceramic blocks which radiate the heat
when lit
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Gas Fires
Gas fire, open flue, 1980 or later (open fronted), sitting proud of and sealed to
fireplace opening, with or without back boiler unit
– This type of gas fire is a bit more modern, it must be sat in front of the fireplace,
rather than being built into it
– Open fronted in this case means the combustion gases are taken from the room, so
the heater is not sealed. There may be a glass panel in front of the
coals on this type of appliance, but it does not seal the unit.
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Gas Fires
Flush fitting live fuel effect gas fire (open fronted), sealed to fireplace
opening, with or without back boiler unit
– This appliance sits in the fireplace, it is usually a single unit which fits in the
fireplace and controls the airflow up the chimney
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Gas Fires
Decorative fuel effect gas fire, open to chimney
– This type of gas fire is similar to a flush fitting live fuel effect gas fire, but there
is no control of the airflow, so the efficiency of the appliance is quite poor
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Gas Fires
Gas fire or wall heater, balanced flue
– This type of appliance will have a balanced flue on the external wall
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Gas Fires
Condensing gas fire
– Should have a condensate pipe and fanned flue
– These types of gas fire are not particularly common, the main
manufacturer is Mantis
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Gas Fires
Gas fire, closed fronted, fan assisted
– the appliance must be sealed from the room
– A glass panel which does not seal off the appliance is not considered a ‘closed
fronted’ appliance
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Gas Fires
Flueless gas fire, secondary heating only
– This is a very efficient type of gas fire
– There should be no flue coming from the appliance, so it can be freestanding
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Oil Room heaters
There are less oil room heaters to choose from
– Room heater, pre 2000, with or without back boiler
– Room heater, 2000 or later, with or without back boiler
– Bioethanol heater, secondary heating only
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Oil Room heaters
• Take care to ensure they use oil, there should be an oil tank present at the
property
The age of oil room heaters should be based on how old they look
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Oil room heaters
Bioethanol heater
– These appliances must use bioethanol fuel
– the bioethanol is in liquid or gel form
– They can be freestanding because they do not need a fixed fuel
supply or flue
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Solid Fuel Room Heater
• Solid fuel room heaters are generally quite inefficient appliances as the
majority of the heat is lost up the chimney or flue
• The following options are available
– Open fire in grate with or without back boiler
– Closed room heater with or without back boiler
– Stove (pellet fired) with or without back boiler
Use house coal, smokeless fuel, wood, dual fuel
• These appliances can burn a variety of solid fuels, but the exact options
are determined by whether or not a property is located in a Smoke Control
Zone
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Solid Fuel Room Heater
Open fire in grate
– Fuel options include coal, wood logs, and smokeless fuel
– This is a highly inefficient heating appliance, at 37%
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Solid Fuel Room Heater
Closed room heater
– Can use coal, wood logs and smokeless fuel
– This is a more efficient solid fuel appliance than an open fire, at 65%
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Solid Fuel Room Heater
Wood pellet stove (Biomass)
– This device is designed
specifically to burn wood
pellets
– This device is 65% efficient
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Electric Heaters
• There are three types of electric
heaters
•
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– Panel, convector or radiant
heater
– Water or oil-filled radiators
– Portable electric heaters
Portable electric heaters should not
be specified unless they are
secondary heating to a storage
heating system
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Electric Heaters
Electric panel, convector or radiant heaters
– This includes fixed panel heaters and electric fires
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Water or oil filled radiators
Water or oil filled radiators
– These should be fixed heaters
– They look like normal wet radiators but have electrical wires where you would
usually see pipe work
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Portable
Portable electric heating
– This type of electric heater should not be fixed
– The heater should be self-supporting and have a flex and plug
– This type of heater should be ignored unless the dwelling has electric storage
heating
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Fuel Types
There are a variety of fuels available in RdSAP
• Most heating systems are designed to run on a specific fuel, so make
sure you know the fuel type of the heating device.
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Mains Gas
• Mains gas is piped to individual properties and one of the cheapest and
cleanest fuels widely available in the UK
• You musts state whether mains gas is present or not in an EPC. If a
property has a gas meter or gas burning appliance within the property it
has mains gas.
• A closed of gas pipe does not mean mains gas is available
• If mains gas is available in the local area, but has not been piped to the
specific property, then mains gas is not available
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Heating Oil
• Heating oil is commonly used in
areas which do not have a mains
gas supply
• The oil is stored in a large tank on
site and must be delivered in bulk
• Oil tanks are usually metal or
moulded plastic
• Oil boilers are usually larger and
more heavy duty than gas boilers
• It is possible to get, regular,
combi and condensing oil boilers
• The boiler pictured is a regular oil
boiler.
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Oil Fired Combi Boiler
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Condensing oil boiler
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Oil Tank
This is typically the type of tank you will find with heating oil. They are usually
plastic. But can be sunk into the ground meaning you will only see the filling cap.
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Bulk LPG
•
•
•
•
LPG – Liquid Petroleum Gas
This is an alternative to oil in areas which are not on mains gas
Boilers are manufactured to run on LPG specifically.
Several boiler manufacturers have a mains gas and LPG version of some of
their boilers, so it is important to confirm whether or not it is LPG
• LPG is stored in a tank and will be delivered in bulk to the
property
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LPG - Bottled
• Some properties may use LPG
cylinders rather than a bulk tank.
• LPG is a manufactured fuel, which
means both bottled and bulk LPG
have a much higher costs than most
other fuel types.
• The manufacture process also
increases the carbon emissions.
• This results in a poor EPC rating,
usually 2 or 3 bands lower than a
property with a mains gas equivalent
boiler.
• It may be worth advising your client
of this during the survey
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Underground Bulk LPG
• Some properties may have their LPG tank buried in their garden.
• You will only be able to see a man hole cover.
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Electricity
• There are a few electricity meter options in RdSAP
–
–
–
–
Single
Dual
Unknown
24 hour (Scotland Only)
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Electricity
• Single meter
– This indicates the property is on a standard tariff
– the meter should only show one reading
– A few examples of single meters are shown below
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Electricity
• Dual meter
– This means a property has two electricity rates
• a standard rate, charged for electricity used during the day
• an off peak rate, charged for electricity used over night and electric
storage systems have been developed to take advantage of this
– This type of electricity tariff is also known as Economy 7, this is
because the tariff applies to 7 hours overnight
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Electricity
• A dual tariff can be identified by the meter present at the property.
– Originally properties with a dual tariff would have two electricity meters, one for
each tariff
– More modern meters tend to have both readings in one meter, either a mechanical
meter with two readouts visible, or a digital meter with a button to switch between
the two readings
• Some modern meters have ‘single phase’ printed on them, this does
not indicate the tariff, as most dwellings have a single phase
supply.
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Electricity
• 24 Hour Meter
– The 24-hour tariff option, which is almost exclusive to properties in Scotland,
does have some exceptions for England.
– Specifically, there are properties in Northumbria that are supplied by Scottish
Power and use the 24-hour tariff
– It is highly unlikely the 24 hour tariff will be found anywhere else in England,
Wales or Northern Ireland
• Unknown meter
– this option should be used if it is not possible to access the meter.
– The software will assume a single meter, unless the main heating or
water heating require an off-peak tariff (such as storage heaters)
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Solid fuel
• Coal
– can be used in open and closed room heaters
– cannot be used in Smoke Control Zones
• Anthracite
– used as a replacement for coal in Smoke Control Zones
– Supplied in grains or nuts, smaller than coal
– Can be used in solid fuel central heating boilers
• Smokeless fuel
–
–
–
–
Used as a replacement for coal in Smoke Control Zones
Can be used in open and closed room heaters
Much more expensive than coal
Is a manufactured fuel, the coals are usually a uniform shape
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Solid fuel
•
Wood
– also known as 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
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Biomass & Biofuel Boilers
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Biomass and Biofuel
• Biomass can be burnt directly to provide heat in buildings. Wood from
forests, urban tree pruning, farmed coppices or farm and factory waste, is
the most common fuel and nowadays is used commercially in the form of
wood chips or pellets, although traditional logs are also used.
• Biomass boilers can be designed to burn smokeless fuel to comply with
the Clean Air Acts.
• Boilers can be fed automatically by screw drives from fuel hoppers. This
typically involves daily addition of bagged fuel to the hopper. Electric firing
and automatic de-ashing are also available.
• Biomass boilers replace conventional fossil fuel boilers and come with the
automated features mentioned above. Fuels other than wood, such as
straw can also be used.
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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.
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Any questions on material covered
so far?
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Heating Controls
Central heating systems generally have some or all of the following controls
• Programmer
• Room thermostat
• Thermostatic radiator vales (TRVs)
Some systems have additional controls:
- Boiler energy manager
- Zone control
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Boiler Programmer
• A programmer determines the time the heating is switched on and off
• Programmers can be mechanical or digital
• They usually control the space and water heating
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Room Thermostat
• A room thermostat measures the air temperature, if the set temperature has
been reached it will feed back to the boiler to switch off
• A room thermostat must be separate to the boiler, they are usually wall
mounted.
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Room Thermostat
• A thermostat situated on a boiler is most likely there to control the temperature
of the water in the system, rather the actual room temperature
• If a wireless thermostat is fitted then the thermostat may not be in a fixed
position, but the transmitter should be located near the boiler.
• Combined programmer and room thermostats are also quite
common now, the time and temperature will be shown on the
display.
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Not a room thermostat
These are examples of Frost stats
• A frost stat can be set at a low temperature
• They are designed to turn the boiler on when the temperature gets low to
prevent the pipes freezing.
• They are usually fitted near a boiler when it is located in or garage or
outbuilding where the temperature can drop very low
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Thermostatic Radiator Valves (TRV’s)
• TRVs sense the temperature of individual radiators, the sensitivity can be
adjusted by turning the valve
• They will cut off the flow into the radiator if it has got up to temperature
• Radiator cut off valves are not classed as TRVs as they are only used to manually
shut off a radiator
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Bypass
• If a system has a programmer and TRVs it must have a bypass.
• A bypass is a radiator with no TRV.
• If all other radiators TRVs are turned down there is an outlet (bypass) for
the boiler
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Boiler Energy Manager
• This device works in conjunction with a programmer and TRVs to adjust the
output of a boiler based on a variety of external data including
– Weather compensator – this adjusts the output of the boiler based on internal
or external temperatures. Sensors are usually located around the building for
this type of system
– Net setback – maintains a low temperature overnight to reduce the warm up
time for the system in the morning
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Zone control
• A property can be split into zones
which can have independent
control of the heating
• Each zone should have it’s own
room thermostat
• There may be one programmer
with the facility to independently
control each zone
• This type of system is usually
found in larger properties
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Boiler Interlock
• This is not a physical device but an arrangement of the system controls so
as to ensure that the boiler does not fire when there is no demand for
heat.
• In a system with a combi boiler it can be achieved by fitting a room
thermostat.
• In a system with a regular boiler it can be achieved by correct wiring
interconnections between the room thermostat, cylinder thermostat, and
motorised valve(s).
• It may also be achieved by a suitable boiler energy manager.
• In systems without an interlock the boiler is kept cycling even though no
water is being circulated through the main radiators or the hot water
cylinder.
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Boiler Interlock
Cylinder
thermostat
Programmer
TRVs
Room
thermostat
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Other Heating Controls
Storage heaters have either manual or automatic charge control.
– Most will have manual controls on the top of the heater.
– Some may have automatic control, this means they have sensors which
monitor the difference in temperature in the room and the heater. The
temperature is the automatically adjusted to the correct level.
• Appliance thermostats appear on electric heaters and other room heaters,
they control the temperature for the individual appliance
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Questions
•
•
•
•
•
•
Name the most common types of gas boiler?
How do they work?
Which are most efficient?
How would you identify them during a survey for an EPC?
How are central heating systems controlled?
What are the main components and how do they contribute to the
efficient operation of the system they control?
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Heating
Any Questions?
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