Our 2020 VisionUpdate on Building Services Design & Sustainability

Presentation by Dr Christopher Marien, Emily Mansfield and Patroula Christopoulou

23rd January 2020

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Content

• Building Regulations – What’s changing and the impacts (Emily Mansfield)

• SAP Methodology – Key changes (Emily Mansfield)

• Passive House – Basic Principles (Patroula Christopoulou)

• Estimated Construction Costs for Passive House Certification (Patroula Christopoulou)

• Heat Pump Solutions Review (Chris Marien)

• Achieving Zero Carbon (Emily Mansfield)

• Hydrogen Fuel (Chris Marien)

SAP 10 And Part L Updates

SAP Methodology – Key Changes

• Thermal bridging (y-value) default increased to 0.20W/m2K and psi-values increased

• Solar Photovoltaic (PV) array – recognises use of battery storage and diverter

• Community heating distribution pipework losses factor increased to 2 (1.5 if CP1 applied)

• Fuel Tariffs updated – p/kWh of energy used within dwelling

• CO2 emission factors updated – kgCO2/kWh of energy used within dwelling

• Primary energy factors updated – kWh of energy used to deliver fuel / kWh of energy used within dwelling

Updated Fuel Tariffs

Fuel Type SAP 2012 SAP 10.1

Mains Gas 3.48 3.93

Electricity (standard tariff) 13.19 17.56

Electricity Export 13.19 5.30

p/kWh

Price of electricity is shown to increase by 4.37p/kWh compared to current SAP methodology and to be almost five times more expensive than mains gas

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

Mains Gas Electricity

p/k

Wh

Fuel Tariffs

SAP 2012 SAP 10.1

13%

347%

33%

Updated CO2 Emissions

Fuel Type SAP 2012 GLA SAP 10.1

Mains Gas 0.216 0.210 0.210

Electricity 0.519 0.233 0.136

kgCO2/kWh

The CO2 emissions factor proposed for electricity take into account the decarbonisation of the National Electricity Grid and are shown to be lower than mains gas

These figures could potentially change again once Part L consultation is complete

0.000

0.100

0.200

0.300

0.400

0.500

0.600

Mains Gas Electricity

kgC

O2/

kWh

CO2 Emission Factors

SAP 2012 GLA London Plan SAP 10.1

3% 3%

55% 74%

35%

Updated Primary Energy

Fuel Type SAP 2012 SAP 10.1

Mains Gas 1.220 1.130

Electricity 3.070 1.501

kWh/kWh

Primary Energy Factor for mains gas has slightly reduced

Similar to CO2 emissions, the primary energy factor for electricity has significantly reduced. However, it still remains higher than mains gas

0

0.5

1

1.5

2

2.5

3

3.5

Mains Gas Electricity

kWh

/kW

h

Primary Energy Factors

SAP 2012 SAP 10.1

7%

51%

33%

Part L Consultation Issued October 2019Area What’s changed Impact

Criterion 1 Focuses on primary energy as well as CO2 emissions Careful design required for electric heating

Householder Affordability New regulation requirement for heating, hot water and lighting – based on EPC

Direct electric heating may not be affordable – unless improvements made to reduce space heating demand

Summer overheating New regulation? Takes into account pipework losses and water storage losses

Require dynamic simulation? – Already part of GLA requirements

Air pressure testing Part F may require all dwellings to be tested Already common practice by most developers

Electricity CO2 emission factor decreased

Now shown as 0.136kgCO2/kWh – Lower than gas! More improvement measures to be implemented –increased amount of PV array

Electricity primary energy factor decreased

Now shown as 1.501kWh/kWh Moving closer to gas, makes it easier to achieve the primary energy targets

Electricity cost increased Now shown as 17.56p/kWh (based on 5-year average predicted values)

Already becoming more expensive – leading to poor EPC rating

Two options proposed for Notional Dwelling (TER)

Option 1- Improved building fabric (triple glazing), WWHR (20% reduction)Option 2 – Improved technologies (WWHR & PV) and smaller building fabric improvements (31% reduction)

Option 2 government’s preferred option – estimated increase in cost of £4,847 saving households £257/year. It is expected builders will choose less costly ways of meeting targets

Passive House Principles

Definition of Passive House

“A Passivhaus (German Standard) House is a building, in which thermal comfort can be provided solely by heating or cooling of the fresh air flow* which is required for good indoor air quality” Passipedia

*without using recirculation

In Practice:

• A building with space heating requirements designed close to the theoretical minimum

• Using Passive principles to their full extent before active design – i.e. insulation before heating

• With low energy design included in all the services: heating, hot water, lighting and appliances

• Heating doesn’t necessarily have to be achieved through air heating Goldsmith Street, Norwich – Winner of the RIBA Stirling Prize 2019

Principles of Passive House – New Build

Item: Criteria Strategy

Air-tightness 0.6ach @ 50Pa Test rate of approx. 1m3/h.m2

Surface temperature >17oC Triple glazing and thermal bridge free junctions

Summer overheating Must not exceed 25oC for more than 10%

Passive House based on constant internal temperature of 20°C

Ventilation ∼30m3/h.person MVHR

Heating 15kWh/m2/year or 10W/m2 Promotes ‘fabric first’ approach

Primary Energy 135kWh/m2/year UK figure (differs based on location)

Renewable Primary Energy

60kWh/m2/year (Classic)45kWh/m2/year (Plus)35kWh/m2/year (Premium)

Ensure renewable technologies are not used as bolt on to achieve the Primary Energy Target

Co

mf

or

tE

ne

rg

y

Key Elements - Shape & Orientation

• Simple shape – lower form heat loss factor

• Reduce difficult detailing and thermal bridging

• Optimise orientation – Solar gains

Passivhaus Institute / AECB Carbon Lite / GOSOL

The lower the form heat loss factor the better

Key Elements – Building Fabric & Ventilation

+ + +

EXTRACT AIR

EXTRACT AIR

SUPPLY AIR

SUPPLY AIR

INTAKE

EXHAUST

MVHR

BATHROOM

KITCHEN

BEDROOM

LIVING ROOM ∞

Building Regulations Vs Passive House Standards

Building Element Notional Building(Part L1A 2013)

Passive House

U-values (W/m2K):

• Walls 0.18 0.15

• Roofs 0.13 0.15

• Floors 0.13 0.15

• Windows (g-value) 1.40 (0.63) 0.85 (0.50)

• Doors 1.00 1.00

Thermal Bridging (y-value) ACDs 0.05W/mK*

Design Air Permeability Rate (@50Pa) 5m3/hm2 1m3/hm2

Mechanical Ventilation Intermittent extract MVHR (certified)

Passive House Estimated Construction Costs

Passivhaus Trust carried out a study in October 2019 – Passivhaus Construction Costs

Applying best practice extra costs indicates an uplift in costs of approximately 8-11% higher when set against comparable projects - £115/m2 (using Spons UK build cost for terraced housing)

Extra costs estimated at 4% if the quality assurance process of Passive House becomes a standard

Areas shown to have greatest additional costs:

• Wall & roof structures• Use of MVHR – Typical Non-PHI: £1,098, Typical PHI certified: £2,820• Airtightness Testing (more rigorous standard)• Site supervision (approximately £80/m2)

Passive House standards can be used as a driver for on site skill and quality uplift

Heat Pump Solutions Review

1) Hybrid: Heat Network + Gas Boilers + Centralised ASHP

2) Centralised ASHP: Low Temperature Heat Network + Centralised ASHP

3) Two-Stage Communal System: Ambient HN + Centralised ASHP + Individual WSHP

4) Individual ASHP

5) Individual Exhaust Air Heat Pump (two stage MVHR-EAHP)

1. Hybrid: Heat Network + Gas Boilers + Centralised ASHP

Mix Valve 55oC - 70oC

<40oC

80oC

40oCASHP: Min 45oC Max 65oC

<55oC

COP - Coefficient of Performance (i.e. efficiency)

1no. ASHP Unit:- 43kWthermal- 500kg- 760W x 2000L x 1700H- Circa £23k each

Gas Meter

ThermalStore

ThermalStore

ThermalStore

2. Centralised ASHP: Low Temperature Heat Network + Centralised ASHP

Max 55oC

<40oC

COP - Coefficient of Performance (i.e. efficiency)

>50oC

55oC

1no. ASHP Unit:- COP 1.5 - 3- 43kWthermal- 500kg- 760W x 2000L x 1700H- Cost circa £23k each

Design Considerations:- Location (roof / landscape)- Weight- Noise- Visual- Electrical Load / Substation(s)- Low Temp HN ( min/max 55oC)- UFH - Minimise dwelling heat demand

ThermalStore

3. Two-stage Communal System: Ambient HN + Centralised ASHP + Individual WSHP

25oC

15oC

1no. ASHP Unit:- COP 1.5-3- 43kWthermal- 500kg- 760W x 2000L x 1700H- Cost circa £23k each

Design Considerations:- ASHP Location (roof/landscape)- ASHP & WSHP Weight- ASHP & WSHP Noise- ASHP Visual- Electrical Load/Substation(s)- HN Pipework size (increased SV) - Diversity Calculations- UFH - Cost Unknown- No/Limited Market Examples - O&M Market Availability

1no. WSHP Unit:- COP 4

- 4kW & 6kW - 353kg

- 550W x 560L x 2000H- Primary Flow Rate: 0.25l/s- HWS Reheat 2hrs-2.75hrs

- Immersion heater- Noise Rating 35

- Cost: £5-10k?

HWS

WSHP

4. Individual ASHP

Design Considerations:- ASHP Location (roof / landscape / Façade/ Balcony)- ASHP Noise- ASHP Visual- Electrical Load / Substation(s)- HP Pipework Length max 30m - Internal Distribution (Risers & Service Voids)- UFH / Rads

1no. ASHP Unit:- COP 1.5 - 3- 4kW - 12kW - Internal Unit: 650W x 730D x 1800H (130kg)- External Unit: 1085W x 360L x 735H (80kg)- Immersion heater- Noise Rating 35- Cost: £2-4k

Radiator Sizes:

Flow Temp: 70oCOutput: 500w

Height: 500mmWidth: 300mm

Flow Temp: 50oCOutput: 500w

Height: 500mmWidth: 800mm

HWS

5. Individual Exhaust Air Heat Pump (Two Stage MVHR-EAHP)

Design Considerations:- Location (external wall)- Noise- Electrical Load / Substation(s)- Large Ventilation Duct Size (160mm dia) - Warm Air heating (i.e. no UFH / Rads)- Passive House levels of thermal efficiency - Low water use taps and showers.

1no. MVHR-EAHP Unit:- COP: 4-6- Capacity: <2.5kW - Internal Unit: 900W x 610D x 2065H- Duct Connections: 160mm (dia)- HWS Cylinder: 180Ltrs- HWS Reheat: trickle? - Immersion heater: 1.5kW- Noise Rating: ?- Ventilation Rate: upto 300m3/hr- Cost: £9k

Images: Twinn, C (2019). Heat Autonomy Life After District Heating (on route to zero carbon)

Hot Water Mode:

ComparisonSolution Policy

Compliance (LP 35%)

Heat Pump Type

Additional Heat Sources

HIU Required Heat Network Flow / Return

Temps

Heat Network Auxiliary Equipment

Substation Required*

Seasonal use of ASHP

Source of Fuel Heat Metering System

Capital Cost Residents Affordability

Hybrid: HN + Boilers + ASHP

Yes(35-40%)

Centralised ASHP

Centralised gas boilers

Yes 70-55oC / <40oC

Circulator pumps, distribution pipework, pressurisation unit, filtration unit

Less likely Majority of the year where high COP can be maintained

Electricity and gas

Yes Comparable with standard HN+CHP

Potentially lower thancurrent heat networks owing to optimum efficiencies

ASHP Heat Network

Yes(40-60%)

Centralised ASHP

None Yes 55oC / <40oC Circulator pumps, distribution pipework, pressurisation unit, filtration unit

Highly Likely All year Electricity only Yes Higher than standard HN-CHP

Potentially high cost owing to low COP in Winter

ASHP + WSHP (ambient loop)

Yes(50-70%)

Centralised ASHP + WSHP in dwelling

HWS cylinder with Immersion heater

NoWSHP and HWS cylinder

25oC / 15oCHeat topped up in dwelling via WSHP

Circulator pumps, distribution pipework, pressurisation unit, filtration unit

Highly Likely All year Electricity only Yes Very high (cost of communal system + domestic WSHP)

Potentially high cost owing to HWS immersion heater

Individual ASHP

Yes(40-60%)

Individual ASHPInternal & External unit

HWS cylinder with Immersion heater

NoHWS cylinder

n/a n/a Highly Likely All year Electricity only No £2-4k/unit Potentially high cost owing to HWS immersion heater

MVHR-EAHP Yes(60-70%)

EAHPInternal unit

HWS cylinder with Immersion heater

NoHWS cylinder

n/a n/a Highly Likely All year Electricity only No £9k/unit Potentially very high cost owing to HWS immersion heater, limited heat capacity and high air change rate

Achieving Zero Carbon Homes

Energy Hierarchy

Source: Greater London Authority

Carbon Offset Payment currently £60/tonneCO2 over 30 years (£1,800/tonneCO2)

Draft London Plan proposes £95/tonneCO2 over 30 years(£2,850/tonneCO2)

Example House – Improved Fabric + ASHP

SAP 2012

SAP 10

%

42% Wet 0kWp £4,090

£

£%

61% Wet 0kWp £1,836

Example House – Improved Fabric + ASHP + PV + Battery

SAP 2012

SAP 10

%

101% Wet 3.27kWp £0

£

£%

100% Wet 3.27kWp £0

Apartments (54 Units) – Improved Fabric + Community Heating (ASHP + Boilers) + PV SAP 2012

%

40% Wet 27.5kWp £100,203 / £1,856/unit

£

SAP 10

%

52% Wet 27.5kWp £70,575 / £1,307/unit

£

Heating System:SAP 2012 SAP 10

£/year: Improvement: £/year: Improvement:

Main gas boiler 177.94 3.07% 200.95 7.32%

Direct electric 578.72 3.09% 770.45 35.26%

ASHP 300.96 29.85% 400.67 53.14%

Heating System:SAP 2012 SAP 10

£/year: Improvement: £/year: Improvement:

Main gas boiler 137.43 19.23% 155.20 24.80%

Direct electric 430.79 4.48% 573.51 36.19%

ASHP 239.18 38.55% 318.42 58.94%

Heating System:SAP 2012 SAP 10

£/year: Improvement: £/year: Improvement:

Main gas boiler 123.96 102.55% 139.99 69.60%

Direct electric 380.85 101.27% 507.03 100.85%

ASHP 213.85 100.60% 284.70 100.41%

Reducing Energy BillsVersion 1 – Achieving compliance with Part L1A 2013 of the Building Regulations (direct electric heating option requires 1.31kWp of PV to comply with current Building Regulations)

Version 2 – Improved specification to reduce estimated running costs for space heating and hot water

Version 3 – Improved specification to achieve zero carbon (PV requirements – mains gas boiler 2.94kWp, direct electric 4.91kWp and ASHP 3.27kWp)

Percentage of PV Exported to Grid:

Mains Gas Boiler Direct Electric ASHP

Saving from PV (£/year):Total for Space Heating &

Hot Water (£/year):Saving from PV (£/year):

Total for Space Heating & Hot Water (£/year):

Saving from PV (£/year):Total for Space Heating &

Hot Water (£/year):

NO PV N/A 155.20 N/A 573.51 N/A 318.42

50% -127.94 9.49 -127.94 445.57 -127.94 190.48

40% -141.66 -4.23 -141.66 431.85 -141.66 176.76

30% -155.39 -17.96 -155.39 418.12 -155.39 163.03

20% -169.11 -31.68 -169.11 404.40 -169.11 149.31

10% -182.83 -45.40 -182.83 390.68 -182.83 135.59

Percentage of PV Exported to Grid:

Mains Gas Boiler (2.94kWp of PV) Direct Electric (4.91kWp of PV) ASHP (3.27kWp of PV)

Saving from PV (£/year):Total for Space Heating &

Hot Water (£/year):Saving from PV (£/year):

Total for Space Heating & Hot Water (£/year):

Saving from PV (£/year):Total for Space Heating &

Hot Water (£/year):

NO PV N/A 139.99 N/A 507.03 N/A 284.70

50% -287.13 -147.14 -479.53 27.50 -3919.36 -34.66

40% -317.93 -177.94 -530.97 -23.93 -353.62 -68.91

30% -348.73 -208.74 -582.40 -75.37 -387.87 -103.17

20% -379.53 -239.53 -633.84 -126.80 -422.13 -137.43

10% -410.33 -270.33 -685.27 -178.24 -456.38 -171.68

Reducing Energy BillsVersion 2 – Improved specification to reduce estimated running costs for space heating and hot water (based on 1.31kWp of PV for all options) BASED ON SAP 10 FUEL TARIFFS

Version 3 – Improved specification to achieve zero carbon (PV requirements – mains gas boiler 2.94kWp, direct electric 4.91kWp and ASHP 3.27kWp) BASED ON SAP 10 FUEL TARIFFS

Hydrogen Fuel

Hydrogen Fuel

• Hydrogen is being considered to help decarbonise the gas grid

• 100 properties on Keele University campus to be fed with 20% hydrogen mix – HyDeploy now fully operational (News Keele University on 02 January 2020)

• Requires electrical current to split water molecules into hydrogen and oxygen – zero CO2 if from renewable sources

• If successful move to larger test on a public network in North East, followed by another in the North West possibly this year

• If rolled out across the country it could save 6 million tonnes of CO2/year.

Hydrogen Fuel

• Gas boilers need to be replaced? Not with 20% hydrogen blend

• Some boiler manufacturers are producing prototypes that use 100% hydrogen

• BDR Thermea and Worcester Bosch have a ‘hydrogen-ready’ design capable of converting to 100% hydrogen

• Worcester Bosch want the government to stipulate that by 2025, all new boilers on sale should be hydrogen-ready

• Possible new hybrid-system – heat pumps and hydrogen boilers.

Thank You For ListeningAny Questions?

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