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1
Air Source Heat Pump Presentation
Andrew Knill Monmouthshire County Council
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What Made Us Consider Air Source Heat Pumps?
Increased Number Of Complaints From Tenants About Their Solid Fuel and Electric Storage Radiators Systems.
Sharply Rising Cost Of Oil (Winter 2005)
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Solid Fuel Complaints
Older Tenants: Unable To Carry Coal and AshesQuite Expensive To Run
Home Help Often Required.
Younger Tenants: Unable To Control System.
High Running Costs. Dirty To Operate.Danger To Children.
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Electric Storage Radiator Complaints Unable To Control: Too Hot In The Night
and The Morning.No Heat Left
By The Evening.
High Running Costs.
5
Monmouthshire County CouncilBreakdown of Heating Fuel TypesJanuary 2005
Number Of Properties Percentage
Gas 3045 84Oil 58 2Solid Fuel 227 6Electric 310 9
3640 15%
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Cae Capel, Great Oak, Near Raglan. Small rural site of 6 two bedroom bungalows
heated with modern slim-line electric storage radiators.
Properties were built with cavity wall insulation and the loft insulation had recently been upgraded. The windows and doors were single glazed with aluminium frames.
Tenants were all old aged pensioners and had been campaigning for an alternative form of heating for a long time. Their main complaint was the existing systems were expensive to run and the radiators ran out of heat by the evening.
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8
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The tenants wanted LPG or Oil Heating.
The site layout meant that communal LPG or Oil storage tanks would have to be provided as there was insufficient room for individual tanks to be located in the gardens.
The tenants request was turned down because of bad previous experiences with communal storage schemes. (mainly metering, fuel contamination and tanks running out of fuel)
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CAE CAPEL, GREAT OAK
579111315
CAE CAPEL, GREAT OAK
579111315
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After further consultation with the tenants it was agreed to provide them with a wet central heating system with radiators fuelled by Combined Electric Primary Storage Units.
The units chosen were the Gledhill Electomate 2000’s
The systems were to use Tariff 10 electricity.
The tenants were to be set up on the Easy Warm scheme to ensure their fuel bills were capped and affordable.
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Enquiries were made to the electricity supplier over the capacity of the network in June 2005.
It took until October 2005 before a quotation was received.
The quotation was for the sum of £7,500 and specified a minimum lead in time of 3 Months as a new transformer would be required in the village.
The quotation was immediately withdrawn by the electricity supplier as they claimed they needed more information about the Combined Electric Primary Storage Unit.
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The Dilemma A major internal refurbishment program was
due to commence on the site at the beginning of January 2006. The work was to include kitchen and bathroom refurbishment, new central heating systems and electrical rewiring.
It quickly became clear that we would be unable to upgrade the electricity supplies in time.
By coincidence we acquired a HeatKing Air Source Heat Pump Brochure which under different circumstances may have been set aside.
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What caught our eye in the brochure was that even at an external temperature of -10 Deg C the coefficient of performance (COP) of the Heat Pump was 2 !!HeatKing BWarm 8000 COPs
At Water Flow Temperature Of 50 DegC
0 5 10 15-15 -10 -51.5
2.0
2.5
3.0
3.5
4.0
4.5
Ambient Temperature (Deg C)
CO
P
50 DegC
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Cae Capel Bungalows:-Floor Plan
LIVING ROOM
KITCHEN
STOREBED 2
BED 1
BATHROOM A/C
HALL
ExternalStore
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Installation Of Air Source Heat Pump Central Heating At Cae Capel, Great Oak
Heat Loss And Radiator Selection
ROOM NAME Hall Lounge Cloaks Bath Bed 1 Bed 2 Kitchen TOTAL
ROOM HEAT LOSS Watts 507 1887 124 712 1064 664 1041 5999
Flow Temperature DegC 50 50 50 50 50 50 50
Return Temp DegC 45 45 45 45 45 45 45
Mean Temp DegC 47.5 47.5 47.5 47.5 47.5 47.5 47.5
Room Temp 18 21 18 22 18 18 21
D T Mean Temp Diff 29.5 26.5 29.5 25.5 29.5 29.5 26.5
Correction Factor @ DT 0.41 0.36 0.41 0.35 0.41 0.41 0.36
RADIATOR OUTPUT REQ. 1,223 5,191 299 2,055 2,567 1,602 2,864
DT Correction Factor
25DegC 0.338
30DegC 0.423
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HeatKing BWarm 8000 Pump Duty At Water Flow Temperatures Of 50 DegC
0 5 10 15-15 -10 -50
2
4
6
8
10
12
Ambient Temperature (Deg C)
Dut
y (K
W) 50 DegC
-3
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Locations Of Heat Pumps Must Be Located Outside Bolted Securely To A Wall Or Concrete Base Consider Effect On Circulation Routes Allow Adequate Room For Air Flow And
Maintenance Take Into Consideration Noise From Unit
(Provide screening etc. if necessary) Provide Soak away Or Drain For Condensate Avoid Long Pipe Runs (particularly external
runs) To The Unit.
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Clearance For Access and Good Air FlowHeatKing Bwarm8000
100mm Min
100mmMin
600mmMin
1500
mm
Min
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CAE CAPEL, GREAT OAK
HP HP
HPHP HP579111315
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Schematic Of Air Source Heatpump At Cae Capel, Great Oak
Return
Flow
T T
T Thermostatic Radiator Valve
Pressure Differential Valve
Peglar Gate Valve Or Full Bore QT Valve
Peglar Full Bore PB 300T QT Valve with Stub Handle
s
s
s
s
s s
sWhere indicated with an s bends must be slowand preferably formed insitu where possibleAll bends to main flow and return to be slow
Drain off Cock
AirFlow
AirFlow
s
Hea
tkin
g 80
00
s
s
Hot Out SafetyValve
Cold In
Diverter Valve
s
p
Fill ing Loop
Expansion and Saftey Valve Kit
To Vent
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Approved installers, Installer Training All of the Heat Pumps we have installed have
been fitted by our own Corgi registered engineers.
The training requirements are relatively simple. We ran a 1 day installation training course for our engineers and supervising staff.
Our engineers are able to install the units and attend to minor faults but are not able to work on the refrigeration circuit.
Any faulty units are swapped over and returned to the manufacturer for repair. The manufacturer has provided us with a spare unit and provides a collection service.
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Typical Installation Costs Of Air Source Heat Pump Systems (2 Bed Bungalow) Heat pump £3500 Radiators and pipework £1450 Wiring & Controls CH & HW £550 Hot Water Cylinder £750 Builders Work £650
Total £6900
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Grants Currently there are no grants available for
Air Source Heat Pumps. VAT on the cost of the heat Pumps is 5% We have however received a one off grant
from the Welsh Assembly Government via the Home Energy Efficiency Scheme (HEES Wales) to extend our trial of Air Source Heat Pumps.
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Estimated Comparison of Energy Requirements, Cae Capel
Type Of SystemSAP
RatingRunning Cost *
Energy Requirement CO2
£ GJ KgElectric Storage Radiators
and Electric Immersion Heater
61 328 30.65 3525
Air Source Heat Pump& Electric Immersion
Heater67 286 16.69 1919
Calculated Using SAP 2001 Savings 42 13.96 1605
* Electricity Costs SWALEC 2005
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Estimated Running Costs Of Air Source Heat Pumps From Actual Meter Readings
Annual Electricity Costs Heating and Hot waterActual Electricity
CostsMar 2006-2007
Estimated Non Heating & HW (40% actual)
Estimated Heating & Hot water Only
£ £ £
338 lowest 135 203
600 240 360
390 156 234
569 228 341
725 highest 290 435
Average Cost £315
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Air Source Heat Pump Reliability Fitted a total of 19 units since February 2006 3 Units failed to work on commissioning 1 Unit broke down within 7 days of installation 1 Unit broke down after 8 months running Of the 9 units fitted since last January none
have yet broken down, indicating that early reliability problems have been addressed
We keep a spare unit in store which can be swapped over
in a couple of hours. The faulty unit is then sent back to
the manufacturer in Yorkshire for repair
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Some Of The Advantages Of Air Source Heat Pumps Over Other
Systems Heat production is fully controllable Can be used on standard 60A electricity supplies No bulk storage of fuel is required 50-75% of energy produced is renewable * Sealed units mean no specialist knowledge
required Operation and Maintenance requirements are
very low Long life expectancy typically 20 years+ Low water temperature reduces risk of burning
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Some Of The Disadvantages Of Air Source Heat Pumps Over
Other Systems Installation costs are generally high External units are noisy and require careful sighting Capacity has to be very carefully matched to load Output decreases as external temperature decreases Radiator outputs need to be between 2-3 times
greater Unable to heat water and central heating at same
time Unable to fully heat hot water (efficiently) System needs to be filled with expensive antifreeze
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Schematic Diagram Of Central Heating Only Air Source Heat Pump Installation
Return
Flow
T T
T Thermostatic Radiator Valve
Pressure Differential Valve
Peglar Gate Valve Or Full Bore QT Valve
Peglar Full Bore PB 300T QT Valve with Stub Handle
ss
s
s
s s
s Where indicated with an s bends must be slowand preferably formed insitu where possibleAll bends to main flow and return to be slow
Drain off Cock
AirFlow
AirFlow
s
p
Fill ing Loop
Expansion and Saftey Valve Kit
2KW In LineElectric WaterHeaterOnly Used On SystemsBetween 6-8KW
Hea
tkin
g 80
00
s
s
Safety Valve
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What Is An Air Source Heat Pump ?
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Coefficient Of Performance
The coefficient of performance of a heat pump is the ratio of energy given out to the electrical energy put in.
For a heat pump with a COP of 3 you would expect to get 3KW out for every 1KW you put in.
1 KW would come from electricity and 2KW would come from heat extracted from the air.
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Coefficient Of Performance Against Ambient Temperature
HeatKing BWarm 8000 COPsAt Water Flow Temperatures Of 35 & 50 DegC
0 5 10 15-15 -10 -51.5
2.0
2.5
3.0
3.5
4.0
4.5
Ambient Temperature (Deg C)
CO
P
50 DegC
35 DegC35 DegC
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What Is An Air Source Heat Pump ?