At Euro Energy Services Renewable Energy in Scotland Open Day on October 23rd Thomas Dickson of Glow Worm discusses Air Source Heat Pumps and their application in dwellings across the UK

1. Renewable Energy Open Day
Scotland
ees-renewables.co.uk
0800 294 4104

2. Thomas Dickson
Glow Worm

3. Clearly Heat Pumps
Glow-worm’s NEW range of straightforward air to water heat pump system

4. 4October 26, 2015
•Climate change
•Fuel Security •Fuel Poverty
Key drivers for
recent legislation
changes and
government
incentives
•Carbon Usage
•Legislation
•Building Regs

5. 5October 26, 2015
Why select an air to water heat pump system?
 Oil and LPG price volatility is leading to an
increase in interest in cost effective alternatives
particularly in off gas locations
 Eliminates need for on-site fuel storage, e.g.
LPG, oil or biomass
 Can be used as part of an efficient all-electric
heating solution
 Excellent payback period compared to
alternatives such as standard electric, LPG or oil
 Reduces reliance on imported gas and oil
supplies
 Less external work (and cost) compared to GSHP
Paying for heating is becoming
more painful, investing in a heat
pump now can save more in the
future.

6. 6October 26, 2015
•Evaporator
•Condenser
•Compressor
•Expansion device
•The compressor draws in the
refrigerant gas and circulates it at
high pressure once more round
the system
•This plate to
plate heat
exchanger
transfer the
heat from the
refrigerant into
the heating
circuit
•As the refrigerant passes
through the expansion valve it
expands and draws heat from
it’s surroundings
•The sub-cooler absorbs
heat from the liquid flow
to improve efficiency
•The refrigerant
absorbs the heat
as it changes
from a liquid to a
gas
•The sub-cooler ensures
than any liquid refrigerant is
boiled off before it returns
to the compressor
•Example of a working refrigeration cycle
•14 bar, 67 ºC
•14 bar, 34ºC
•4 bar, 6,5 °C
•4 bar, -3ºC
•14bar,25ºC
•4 bar, 2,5ºC

7. 7October 26, 2015
Air to Water Heat Pumps – How do they work?
Heat pump efficiency
In the example above the COP = 4/1 = 4 (i.e. 400% efficient) so you get 4kW of heat for
1 kW of electrical power consumed
‘Free’ heat from
external air
Electrical power
Heat into heating
system
Heat pump efficiency is stated as
the Coefficient of Performance
(COP)
Heat output (kW)
COP = -------------------------------
Power consumed (kW)

8. 8October 26, 2015
Air to Water Heat Pumps – How do they work?
Low Temperature Heat emitters & DHW
Heat emitter selection and heat pump flow temperature have a big effect on AWHP
performance. Higher temperatures = Lower efficiencies
• The Heater Emitter Guide for Domestic Heat pumps
covers the topic of which emitters to select and how
that selection will affect the overall efficiency.
• A good rule to follow is –
The lower the flow temperature the more efficient the
heat pump. (approx 35ºC flow temperature is ideal)
• Low temperature radiators or UFH make this possible
for heating applications
• For DHW however higher temperatures are required;
selecting the right fit for purpose cylinder is a must to
ensure a highly efficient system.
• AWHPs use an electric immersion heater to
supplement the charging of the DHW; The Glow-worm
system makes sure the heat pump gives as much heat
as possible before bringing in the immersion - giving
greater efficiencies.
• DHW generation therefore is not the most efficient use
of a heat pump, particularly when gas supplies are
available

9. 9October 26, 2015
Sizing a heat pump is a complete system sizing, emitters should be size correctly
for the lower temperature flow that a heat pump provides
Envirosorb3 output table
•When sizing a heat pump system in the UK the heat
pump must be able to do 100% of the heating 99% of
the time with out the need of a back heater.
• Heating system are generally sized at -3°C although
this does change around the UK according to MCS
•Ensure that the output can meet the heating demand
of the property at -3°C is a very good rule of thumb
before a full heat loss calculation is carried out
• Any heat pump system using a flow rate over 50°C
cannot get RHI due to the MCS star rating system for
emitters
•The lower the flow rate of the heat pump the better the
all round performance, the better the performance the
more RHI the end user can receive

10. 10October 26, 2015
Air to Water Heat Pumps – How do they work?
• Maximum heating output for domestic applications is 15kW ( 230V) at A7/W35
• Maximum output temperature is 63°C
• Efficiency decreases with higher output temperatures and lower ambient temperatures,
care must be taken when applying an AWHP to DHW or high temp radiator system
• When installed as primary heat source, you need to correctly size radiators and/or specify
UFH
• When selecting a heat pump, you are really selecting a HEATING SYSTEM that includes
a heat pump as such a complete system design approach should be used.
• To get the best out of your heat pump you want it to run for long periods of time at low
temperatures
• Your radiators / emitters will not get “hot” but will get warm you may need to point this out
to the homeowner
Specifying a heating system – Air to water heat pumps Other Considerations

11. 11October 26, 2015
Direct heat pump system – Cost Focused
Feature Benefit
Heat pump connects directly to the heating
system
Easy to install
Entire system is filled with Glycol Heat pump and system protected down to -15°C
Most simple heat pump installation Quick installation time
Full system controlled centrally (via Systempro) Quick and simple wiring and easy to use

12. 12October 26, 2015
Direct heat pump system with back up heater
Feature Benefit
Heat pump connects directly to the heating
system
Easy to install
Entire system is filled with Glycol Heat pump and system protected down to -15°C
Wall hung 6kW in-line back up heater Gives the heating system a boost in extreme
weather conditions (outside the design)
Full system controlled centrally (via Systempro) Quick and simple wiring and easy to use

13. 13October 26, 2015
Direct heat pump system with buffer
Feature Benefit
Heat pump connects directly to the heating
system
Easy to install
Entire system is filled with Glycol Heat pump and system protected down to -15°C
Wall hung buffer tank Acts a low loss header as well and ensuring a
body of heat is available as multiple zones open
and close
Full system controlled centrally (via Systempro) Quick and simple wiring and easy to use

14. 14October 26, 2015
Direct heat pump system with Hex module
Feature Benefit
Heat pump connects directly to the heating
system
Easy to install
Only the heat pump to hex module is filled with
glycol
Less glycol in the system gives a lower cost and
less maintenance over time
Wall hung Hex module Includes fill and flush points and ErP ready CH
pump.
Full system controlled centrally (via Systempro) Quick and simple wiring and easy to use

15. 15October 26, 2015
Hybrid option

16. 16October 26, 2015
System schematics
•NB : Domestic Hot water production taken care of by system
boiler + storage / combination boiler
•Example Heating
schematic

17. 17October 26, 2015
• Heat pump cylinders are design to match the requirements
and performance of heat pumps.
• The coil sizes within a heat pump cylinder are larger to
increase heat transfer from the lower flow temperatures.
• Typically heat pumps only produce flow temperatures of
55°C instead of 80°C as produced by a gas boiler.
• Glow-worm heat pumps can produce a flow temperature
reaching 63°C making heat up times even better.
• Typical heat up are as quick as 39 mins even at 55°C flow
temperature. (more data follows)
What's the benefit of a heat pump cylinder?
Current cylinders not providing efficient solution for heat pump installations
*25 years guarantee for shell with all other parts covered by 2 years parts and labour

18. 18October 26, 2015
Sustain Boiler Range Overview
Type Outputs kW Size
Combi 25,30, 35 700 x 390mm
System 12, 15, 18, 25, 30 700 x 390mm
Regular 12, 15, 18, 25, 30, 35 600 x 375mm
Key Features
Rear flue option and cupboard fit dimensions
Remote diagnostic options
Low maintenance Aluminium Heat Exchanger
Grundfos High Efficiency pump
ERP Ready A rated boilers
Club Energy Alliance – warranties, servicing, GSR and
Benchmark

19. 19October 26, 2015
•Develop concepts to increase competitive ability of Sustain boiler
Established market leading competitor products
Product Characteristics
Database (PCDB)
Category = boiler, mains gas, combi
Ecoblue
combi
24, 28, 33
Logic
combi
24, 30, 35
Flexicom
combi
35
SAP
annual efficiency [%,Hs]
89.0 89.0 89.1
SAP
winter seasonal Efficiency [%,Hs]
89.9 89.9 90.0
SAP
summer efficiency [%,Hs]
87.3 87.3 79.9
Comparative hot
water efficiency [%,Hs]
77.6 71.0 62.4
SEDBUK
Sustain
boiler UK
25, 30, 35
89.3*
90.3*
87.3*
78.0*
+0.4%
+0.5%
+0.5%
+12.2%
Taskforce
ENOS
targets
ENOS Taskforce Background
*Subject to change (to be revised upwardly)

20. 20October 26, 2015
Thank you for your attention.

21. Renewable Energy Specialists
ees-renewables.co.uk
0800 294 4104