air source heat pumps - thomas dickson - glow worm
TRANSCRIPT
Renewable Energy Open Day Scotland
ees-renewables.co.uk0800 294 4104
Thomas DicksonGlow Worm
Clearly Heat Pumps
Glow-worm’s NEW range of straightforward air to water heat pump system
4May 1, 2023
• Climate change
• Fuel Security • Fuel Poverty
Key drivers for recent legislation
changes and government incentives
• Carbon Usage
• Legislation
• Building Regs
5May 1, 2023
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.
6May 1, 2023
•E
vaporator •
Con
dens
er
• 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
• 14
bar,
25ºC
•4 bar, 2,5ºC
7May 1, 2023
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 powerHeat into heating
system
Heat pump efficiency is stated as the Coefficient of Performance (COP)
Heat output (kW)COP = ------------------------------- Power consumed (kW)
8May 1, 2023
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
9May 1, 2023
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
10May 1, 2023
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
11May 1, 2023
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
12May 1, 2023
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
13May 1, 2023
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
14May 1, 2023
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
15May 1, 2023
Hybrid option
16May 1, 2023
System schematics
• NB : Domestic Hot water production taken care of by system boiler + storage / combination boiler
•Example Heating schematic
17May 1, 2023
• 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
18May 1, 2023
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
19May 1, 2023
•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
SAPwinter seasonal Efficiency [%,Hs] 89.9 89.9 90.0
SAPsummer efficiency [%,Hs] 87.3 87.3 79.9
Comparative hot water efficiency [%,Hs] 77.6 71.0 62.4
SEDBUK
Sustain boiler UK25, 30, 35
89.3*
90.3*
87.3*
78.0*
+0.4%
+0.5%
+0.5%
+12.2%
TaskforceENOStargets
ENOS Taskforce Background
*Subject to change (to be revised upwardly)
20May 1, 2023
Thank you for your attention.
Renewable Energy Specialistsees-renewables.co.uk0800 294 4104