Dwelling Energy Assessment Procedure (DEAP)

Proposed Changes to the DEAP Methodology for Part L 2018

Public Consultation

Page | 2 DEAP: Part L Public Consultation

1 Introduction The Dwelling Energy Assessment Procedure (DEAP) is the methodology for demonstrating

compliance with specific aspects of Part L for Dwellings of the Building Regulations.

DEAP is also used to generate the Building Energy Rating (BER) and advisory report for new and

existing dwellings. DEAP calculates the energy consumption and CO2 emissions associated with a

standardised use of the dwelling.

The energy consumption is expressed in kilowatt hour per square metre floor area per year

(kWh/m2/yr) and CO2 emissions expressed in terms of kilograms of CO2 per square metre floor area

per year (kgCO2/m2/yr). The purpose of DEAP is to produce consistent and reliable evaluations of

energy use in domestic buildings for Building Regulations compliance and Building Energy Rating

purposes, it is not primarily a design tool.

The current DEAP interface (v3.2.1, or DEAP3) and the recently launched DEAP4, a web-based

technology accessed through your browser, do not include the proposed changes to the DEAP

methodology for Part L 2018 in the public consultation.

This document provides a brief overview of the proposed updates to the DEAP methodology and

software. A draft excel version, DEAP 4.1 DRAFT PUBLIC CONSULTATION, of the software

incorporating the most significant changes is available as part of the public consultation.

Page | 3 DEAP: Part L Public Consultation

2 Renewable Energy Ratio It is proposed that the DEAP methodology shall be updated to include the Renewable Energy Ratio

which is to be calculated in line with EN ISO 52000 -2017.

The renewable energy ratio of 0.20 or 20% shall replace the existing requirement for demonstrating

a reasonable minimum level of renewable energy technologies of 10 kWh/m2/yr contributing to the

thermal load or 4 kWh/m2/yr contributing to the electrical energy.

The Renewable Energy Ratio RER = EPren Primary Energy of the Renewables

EPtot Total Primary Energy

The Primary Energy of the Renewables is the sum of the delivered renewable energy multiplied by

the renewable primary energy factor.

The total primary energy is the summary of the total delivered energy multiplied by the renewable

and non renewable primary energy factors.

DEAP 4.1 DRAFT PUBLIC CONSULTATION includes the proposed methodology which is outlined

below.

Photovoltaic system: Calculate the electricity generated by the on-site system, Generated

ElectricityPV, in kWh. The generated electricity is then multiplied by the primary energy factor of the

PV to determine the total and renewable primary energy.

Equation 1 Ep, pv,ren = Generated ElectricityPV x Fp, pv,ren

Equation 2 Ep, pv,tot = Generated ElectricityPV x Fp, pv,ren + Generated ElectricityPV x

Fp, pv,nren

Wind turbine: Calculate the electricity generated by the on-site system, Generated ElectricityWind, in

kWh. The generated electricity is then multiplied by the primary energy factor of the Wind Energy to

determine the total and renewable primary energy factor.

Equation 3 Ep, wind,ren = Generated Electricitywind x Fp, wind,ren

Equation 4 Ep, wind,tot = Generated Electricitywind x Fp, wind,ren + Generated

Electricitywind x Fp, wind,nren

Solar thermal energy system: Calculate the useful thermal energy contribution by the on-site

system, Generated HeatSES. This energy is then multiplied by the primary energy factor to determine

the total and renewable primary energy factor.

Equation 5 Ep, solar,ren = Generated HeatSES x Fp, ses,ren

Equation 6 Ep, solar,tot = Generated HeatSES x Fp, ses,ren + Generated HeatSES x Fp,

ses,nren

Biomass system: Calculate the delivered energy use by the biomass-fuelled on-site system, Energy

Consumptionbiomass, and multiply that by the primary energy factor of the biomass fuel to determine

the total and renewable primary energy factor.

Equation 7 Ep, biomass,ren = Generated Heatbiomass x Fp, biomass,ren

Equation 8 Ep, biomass,tot = Generated Heatbiomass x Fp, biomass,ren + Generated

Heatbiomass x Fp, biomass,nren

Page | 4 DEAP: Part L Public Consultation

Biodiesel system: Calculate the delivered energy use by the biodiesel-fuelled on-site system, Energy

Consumptionbiodiesel, and multiply that by the primary energy factor of the biodiesel fuel to determine

the total and renewable primary energy factor.

Equation 9 Ep, biodiesel,ren = Generated Heat biodiesel x Fp, biodiesel,ren

Equation 10 Ep, biodiesel,tot = Generated Heat biodiesel x Fp, biodiesel,ren + Generated Heat

biodiesel x Fp, biodiesel,nren

Bioethonal system: Calculate the delivered energy use by the bioethonal-fuelled on-site system,

Energy Consumptionbioethonal, and multiply that by the primary energy factor of the bioethonal fuel to

determine the total and renewable primary energy factor.

Equation 11 Ep, bioethonal,ren = Generated Heat bioethonal x Fp, bioethonal,ren

Equation 12 Ep, bioethonal,tot = Generated Heat bioethonal x Fp, bioethonal,ren + Generated

Heat biodiesel x Fp, bioethonal,nren

Heat pump: The environmental renewable contribution is calculated based on the heating, Htg

Demand and hot water, DHW Demand, demand provided by the heat pump minus the energy

consumed by the heat pump:

Equation 13 Environmental Energy = (Htg DemandHP_space - Consumed EnergyHP_space )

+ (DHW DemandHP_water - Consumed EnergyHP_water )

where:

Htg DemandHP_space = space heating provided by the heat pump

DHW DemandHP_water = hot water heating provided by the heat pump

Consumed EnergyHP_space = Consumed energy by the space heating heat pump

Consumed EnergyHP_water = Consumed energy by the water heating heat pump

Equation 14 Ep, HP,ren = Environmental Energy x Fp, HP,ren

Equation 15 Ep, HP,tot = Environmental Energy x Fp, HP,ren + Environmental Energy x

Fp, HP,nren

CHP plant: Calculate the heat demand from the CHP plant for space and water heating, Heat

DemandCHP, in kWh, and use the following equation:

Equation 16 Saved Energy = Heat DemandCHP x [(PEFgas / 0.91) + ((CHPeff_elec x

PEFelec) / CHPeff_heat ) – (PEFgas / CHPeff_heat)]

where:

PEFgas = primary energy factor of natural gas.

PEFelec = primary energy factor of electricity.

Page | 5 DEAP: Part L Public Consultation

CHPeff_elec = electrical efficiency of the CHP plant (entered as a factor), defined as the

annual electrical output divided by the gross calorific fuel input.

CHPeff_heat = heat efficiency of the CHP plant (entered as a factor), defined as the

annual heat output divided by the gross calorific fuel input.

Equation 17 Ep, CHP,ren = Saved Energy x Fp, CHP,ren

Equation 18 Ep, CHP,tot = Saved Energy x Fp, CHP,ren + Saved Energy x Fp, CHP,nren

District Heating: For systems with a capacity of greater than 10MW, including systems using waste

heat, the proposal is that the District Heating Scheme shall submit operational profile to SEAI to

determine the Renewable and Non Renewable Primary Energy factor of the system. Calculate the

heat provision from the District Heating plant for space and water heating, Heat ProvisionDH, in kWh.

Equation 19 Ep, DH,ren = Heat ProvisionDH x Fp, DH,ren

Equation 20 Ep, DH,tot = Heat ProvisionDH x Fp, DH,ren + Heat ProvisionDH x Fp, DH,nren

The Renewable Energy Ratio is calculated as the sum of the primary energy from renewable energy

sources, EPren, divided by the total primary energy use including renewable energy, Eptot.

E fPnren fPren

on-site EPnren

Epren

on-site EPtot

kWh kWh kWh kWh

+ Delivered energy PV/Wind 0.0 0 2.08 0.0 0.0 0.0

+ Delivered energy Other 0.0 0 1 0.0 0.0 0.0

+ Delivered energy Solar 0.0 0 1 0.0 0.0 0.0

+ Delivered energy Biomass 0.0 0.1 1 0.0 0.0 0.0

+ Delivered energy Biodiesel 0.0 0.3 1 0.0 0.0 0.0

+ Delivered energy Bioethanol 0.0 0.34 1 0.0 0.0 0.0

+ Environmental energy HP 0.0 0 1 0.0 0.0 0.0

+ Saved energy CHP 0.0 0 1 0.0 0.0

+ Delivered energy District Heating 0.0 0.5 0.5 0.0 0.0 0.0

+ Delivered energy Grid 0.0 2.08 0 0.0 0.0 0.0

+ Delivered energy Thermal 0.0 1.1 0 0.0 0.0 0.0

TOTAL STEP A 0.0 0.0 0.0

Renewable Primary Energy Factor, Fp, ren

Non Renewable Primary Energy Factor Fp, nren

Total Primary Energy Factor Fp, tot

Photovoltaics Grid Electricity 0 Grid Electricity

Wind Grid Electricity 0 Grid Electricity

Solar Thermal 1 0 1

Biomass 1 0.1 1.1

Biodiesel 1 0.3 1.3

Bioethanol 1 0.34 1.34

Heat Pump 1 0 1

Page | 6 DEAP: Part L Public Consultation

(Environmental Energy)

CHP (Saved Energy) 1 0 1

District Heating District Heating Supplier

District Heating Supplier

District Heating Supplier

Process Energy 1 0 1

Page | 7 DEAP: Part L Public Consultation

3 Primary Energy and CO2 Factors of Electricity The primary energy factor is based on the methodology outlined in EN ISO 52000 -2017, see diagram

below. The proposal is to base the primary energy on the projected energy use for the next 5 years.

It will be reviewed before the end of the 5 year perod.

The projected energy use is based on the projected production from public thermal power plants

(PTPP), renewable sources and CHP taken from the SEAI’s “Irelands Energy Projections: Progress to

targets, challenges and impacts 2017”.

The primary energy factor for electricity is based on the total primary energy of the fuels going into

the PPTP/ CHP and Renewable sources divided by the delivered renewable and non renewable

energy.

The proposal is to use the primary energy factor based on the project average primary energy for the

next 5 years (2018 to 2022).

The Input Energy Demand (NCV), kTOE, is taken from the projections outlined above. For the

purposes of the DEAP methodology this is converted into the Gross Primary Energy Demand using

the factors shown in Table 1.

Page | 8 DEAP: Part L Public Consultation

Table 1 Primary Energy Factor GCV/NCV CO2 Emissions

Kg/ kWh

Coal 1.05 0.964 0.325

Oil 1.05 0.937 0.250

Gas 1.05 0.901 0.185

Peat 1.05 0.964 0.399

Waste 1.05 0.91 0

Hydro 1.0 1.0 0

Biomass 1.0 0.91 0.025

Biodegradable MSW 1.0 0.91 0

Wind 1.0 1.0 0

Landfill gas 1.0 0.91 0

Marine 1.0 1.0 0

Solar PV 1.0 1.0 0

The CO2 emissions for electricity are based on the total CO2 emissions of the fuels going into the

PPTP/ CHP and Renewable sources divided by the delivered renewable energy and delivered non

renewable energy. The CO2 emission factor are as per Table 1 and taken from Energy in Ireland in

consultation with SEAI EPSSU team. (Note the CO2 emissions used in DEAP are as above but

multiplied by the primary energy factor).

Based on the projected 5 year input energy demand and electricity demand, the 5 year average for

the Primary Energy Factor is 1.94 and for CO2 emissions is 0.323. DEAP 4.1 DRAFT PUBLIC

CONSULTATION includes the proposed primary energy factor.

0

1000

2000

3000

4000

5000

6000

2018 2019 2020 2021 2022

Fuels consumed by type of generation

Coal Oil Gas Peat

Waste Hydro Biomass Biodegradable MSW

Wind Landfill gas Marine Solar PV

Page | 9 DEAP: Part L Public Consultation

4 Lighting Energy The proposal is to update the Lighting Calculation to allow a more accurate representation of the

energy use associated with the lighting within the dwelling.

The proposed methodology is as per BRE Consultation paper: Amendments to SAP’s lighting

calculation. The update allows for recent developments with the technology but also ensures that

the lighting provision within the dwelling is adequate and not over or under sized. The key changes

are as follows:

- For fixed lighting and new buildings, the assessor enters details based on design of the

installed lighting, including Wattage and Efficiency of the lighting system.

- For fixed lighting and existing buildings, the assessor enters default efficiency based on

the lamp type/ rating with the lighting level fixed.

- For portable lighting, the energy is assumed to be based on average for dwellings from

survey carried out by BRE for dwellings.

The benefit of the methodology is as follows:

- It allows for different lighting designs to be accommodated

- It allows for new high performance light fittings, such as LEDs, to be accounted for in the

calculation methodology.

- It ensures that where lighting is overdesigned that the additional energy use is

accounted for in the calculation

- It ensures that where lighting is under-designed that the lighting is supplemented with

portable lighting, therefore encouraging adequate lighting to be designed for new

buildings.

The reference building is based on the “Basic Energy Consumption for Lighting” shown in the

workbook. DEAP 4.1 DRAFT PUBLIC CONSULTATION includes the proposed methodology.

Page | 10 DEAP: Part L Public Consultation

5 Hot Water Demand For buildings complying with NZEB requirements it was found that the hot water energy demand can

be significantly larger than the space heating. To date the hot water demand was based on the

number of people/ floor area and did not sufficiently account for the fittings or sources of hot water.

The methodology will be updated to more accurately account for the hot water use within the

dwelling in line with the methodology as per BRE Consultation paper: Amendments to SAP’s hot

water methodology.

BRE found that hot water use for baths and showers accounts for 2/3 rds of all hot water use in the

UK. There are different flow rates for different types of showers and if an electric shower is present,

there is a different source/ fuel for a significant proportion of the water heating.

Therefore, the proposal is to allow water saving technologies to be accounted for in the water

demand calculation which in turn will impact on the hot water energy demand. In summary the

proposal will

- Allows the assessor to enter the flow rate of the showers, or use defaults depending on

the type of shower and presence of flow restrictors

- Allows the assessor to enter if a bath is present

- Allows the assessor to enter electric showers

- Where the design of the system reduces overall water consumption within the dwelling,

the methodology will allow the benefits to be accounted for in the Hot Water Energy

Demand. The proposal will allow the overall water consumption to be calculated in line

with the “The water efficiency calculation methodology”. Details of the calculation are

provided in Appendix A. Where the overall water consumption is less than 125

litres/person/day, the hot water consumption will be reduced.

The reference building will be based on the same number of baths and showers as the actual

building. The showers in the reference building being Vented hot water system + pump and overall

water consumption of greater than 125 litres/ person/ day. DEAP 4.1 DRAFT PUBLIC CONSULTATION

includes the proposed methodology.

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6 Other Proposed Changes to the Methodology

The following outlines a number of proposed changes which have not been included in DEAP 4.1

DRAFT PUBLIC CONSULTATION and may be included when the DEAP methodology and software are

finalised.

6.1 Space Cooling The proposal is to calculate and aggregate the monthly space cooling energy balance for the June to

August inclusive cooling season. Where fixed cooling is installed, the assessor will be able to specify

the fixed air conditioning or heat pump system installed providing cooling, the fraction of dwelling

floor area cooled and the Seasonal Energy Efficiency Ratio (SEER) of the cooling system.

The calculation uses data from the Net Space Heat Demand tab to determine the effect of thermal

mass on heat losses as offset by gains to determine the Net Space Cooling Demand. The cooling

system is assumed to maintain an internal temperature of 24oC for six hours per day for June, July

and August. The resulting electricity requirement is automatically calculated by DEAP when the

assessor enters the proportion of the dwelling cooled by the system and the efficiency of the cooling

system. This calculation is based on IS EN ISO 13790:2008.

The Seasonal Energy Efficiency Ratio (SEER) of the cooling system is taken directly from the Energy

Label. The Energy Label is as per Delegated Regulation No. 626/2011 or Directive No. 2002/31/EC.

6.2 Main Heating Systems

For individual dwellings, the proposal is to allow up to two main heating systems and a secondary

heater.

Occasionally there may be two main heating systems installed in the dwelling. This could, for

example be two separate boilers used to heat different parts of the dwelling or two boilers heating

the same parts of the dwelling. The fraction of main space heat from each of these systems (Main

System 1 and Main System 2) is allocated based on the amount of main space heating provided by

each system. The fraction of the main space heating from each system is based on system design

details if available. Where design details are not available, guidance will be given on how to

determine the fraction.

Control and responsiveness categories where there are two main space heating systems:

The responsiveness category is automatically calculated by DEAP as per equation 4d(1) where there

are two main space heating systems.

The control category and temperature adjustment are based on the combination of the control

measures for both main space heating systems 1 and 2 as outlined in Table 4e.

The efficiency adjustment factor for each of Main System 1 and 2 is entered in DEAP where there are

two main space heating systems.

6.3 High Heat Retention Storage heaters

Page | 12 DEAP: Part L Public Consultation

Allowance shall be made for the inclusion of High Heat Retention Storage Heaters. A ‘high heat

retention storage heater’ is one with heat retention not less than 45% measured according to EN

60531 by a suitably accredited laboratory. It incorporates a timer and electronic room thermostat to

control the heat output that are user adjustable. It is also able to estimate the next day’s heating

demand based on external temperature, room temperature settings and heat demand periods.

6.4 Heat Recovery Mechanical Ventilation

The proposal is to include an efficiency adjustment factor for MVHR systems where ductwork

outside the insulated dwelling envelope is uninsulated.

Clarification shall also be provided where semi-rigid duct systems are used, the performance must

be demonstrated to be at least equal in terms of aerodynamic performance to performance data of

rigid ductwork to use data from Products Characteristics Database.

6.5 Occupancy The proposal is to update the occupancy within the dwelling to follow SAP in the UK which is based

on the following:

Assumed number of occupants if TFA > 13.9: N = 1 + 1.76 x [1-exp (-0.000349 x (TFA-13.9)² )] + 0.0013 x (TFA-13.9)

if TFA <= 13.9: N = 1

6.6 Waste Water Heat Recovery It is proposed to include instantaneous waste water heat recovery systems in the calculation. The

waste water heat recovery uses a heat exchanger to recover heat from waste warm water as it flows

through the waste plumbing system to pre-heat the cold water feed of a shower and a combi boiler

or mains pressure hot water system (thermal store or unvented cylinder). The energy recovered

depends on the temperature of the cold water feed to the dwelling (which varies by month) and the

number and type of systems that are installed. The proposal deals with WWHRS linked to mixer

showers (where the shower water is a mixture of cold feed and that from the combi boiler or mains

pressure hot water system). The WWHRS is located inside the heated envelope.

There are three types of plumbing arrangements for an instantaneous WWHRS:

System A: output of the heat exchanger is fed to both the shower and the combi boiler or hot water

system

System B: output of the heat exchanger is fed to the shower only

System C: output of the heat exchanger is fed to the combi boiler or hot water system but not to the

shower

The proposed methodology is in line with the methodology as per BRE Consultation paper:

Amendments to SAP’s hot water methodology.

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Appendix A Water Efficiency Calculation

The calculation methodology requires the use of water consumption figures provided from

manufacturers’ product details. Before the assessment can be carried out, figures will need to be

collected from manufacturers’ product information to determine the consumption of each terminal

fitting, including:

WCs

i. Flushing capacity for the WC suite including consumption at full and part flush for dual flush WCs.

ii. Where multiple WCs are specified with various flushing capacities, the average effective flushing

volume must be used.

Bidets

Bidets are excluded from the water efficiency calculator.

Taps

i. Flow rate of each tap, at full flow rate in litres per minute measured at a dynamic pressure of 3±0.2

bar (0.3±0.02 MPa) for high pressure (Type 1) taps, or at a dynamic pressure of 0.1±0.02 bar

(0.01±0.002 MPa) for low pressure (Type 2) taps (BS EN 200:2008, sanitary tapware, single taps and

combination taps for supply systems of type 1 and 2. General technical specifications) including

any reductions achieved with flow restrictions.

ii. Where multiple taps are to be provided (e.g. separate hot and cold taps) the flow rate of each tap

will be needed in order to calculate an average flow rate.

iii. For “click taps” and other taps with a “water break”, the manufacturer’s stated full flow rate

should be used to perform calculations (measured as described above). Do not use the flow rate at

the break point. A factor for percentage of flow rate is already assumed within the use factor for

taps. There is currently no research to provide a separate use factor for “click taps” so a standard

use factor is applied.

iv. Taps on baths should not be included in the calculation as the water consumption from bath taps

is taken account of in the use factor for baths.

Baths

i. Total capacity of the bath to overflow, in litres (excluding displacement, this is already included in

the use factor for baths).

ii. Where multiple baths are specified with various capacities, the average must be used.

iii. Spa hot tubs are not included in the water efficiency calculator as they are generally not filled on

a daily basis and their water consumption over a year is minimal.

Showers

i. Flow rate of each shower at the outlet using cold water (T 30˚C), in litres per

minute measured at a dynamic pressure of 3±0.2 bar (0.3±0.02 MPa) for high pressure (Type 1)

supply systems, or at a dynamic pressure of 0.1±0.05 bar (0.01±0.005 MPa) for low pressure (Type

2) supply systems (BS EN 1112:2008, Sanitary tapware. Shower outlets for sanitary tapware for

water supply systems type 1 and 2. General technical specifications).

ii. Where multiple showers are specified with various flow rates, the average must be used.

Water softeners (where present)

Page | 14 DEAP: Part L Public Consultation

i. Percentage of total capacity used per regeneration cycle.

ii. Water consumed per regeneration cycle (litres).

iii. Average number of regeneration cycles per day.

iv. Number of occupants (based on two occupants in the first bedroom and one occupant per

additional bedroom assuming two occupants in studio flats).

v. Water softeners that do not have a water consumption such as electromagnetic types, are not

included in the calculation.

i. Waste disposal units (where present)

i. Where present, a standard consumption of 3.08 litres per person per day must be assumed.

External taps

i. Flow rates of external taps are not included in the calculation as a fixed allowance of five litres per

person per day is assumed for external water use.

Rainwater/ Wastewater harvesting

Rainwater harvesting and greywater recycling may be used as a means of reducing water

consumption to achieve higher water efficiency performance levels. This may be needed where

options for improving the efficiency of terminal fittings (taps, WCs etc.) have been maximised and

further savings are still needed:

a. Greywater (in accordance with BS 8525)

i. Manufacturer or system designer details on the percentage of used water to be recycled, taking

into account the storage capacity of the system.

ii. The volume of recycled water collected from waste bath, shower and washhand basin, with the

volume collected calculated in accordance with Table A1.

iii. The consumption of fittings where greywater is to be used in accordance with Table A1 which can

include WCs

b. Rainwater (in accordance with BS 8515)

i. Collection area

ii. Yield co-efficient and hydraulic filter efficiency

iii. Rainfall (average mm/year)

iv. Daily non-potable water demand

The water efficiency calculator

(1) (2) (3) (4)

Installation type Unit of measure

Capacity/ flow rate

Use factor

Fixed use (litres/ person/ day)

Litres/ person/day = [(1) x (2)] + (3)

WC (single flush) Flush volume (litres)

4.42 0.00

WC (dual flush) Full flush volume (litres)

1.46 0.00

Part flush volume (litres)

2.96 0.00

WCs (multiple fittings)

Average effective flushing volume (litres)

4.42 0.00

Taps (excluding Flow rate 1.58 1.58

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kitchen/utility room taps)

(litres/minute)

Bath (where shower also present)

Capacity to overflow (litres)

0.11 0.00

Shower (where bath also present)

Flow rate (litres/minute)

4.37 0.00

Bath only Capacity to overflow (litres)

0.50 0.00

Shower only Flow rate (litres/minute)

5.60 0.00

Kitchen/utility room sink taps

Flow rate (litres/minute)

0.44 10.36

Waste disposal unit Litres/use If present = 1 If absent = 0

3.08 0.00

Water softener Litres/person/day 1.00 0.00

(5) Total calculated use = (Sum column 4)

(6) Contribution from greywater (litres/person/day)

(7) Contribution from rainwater (litres/person/day)

(8) Normalisation factor

0.91

(9) Total water consumption = [ (5) – (6) – (7) ] x (8)

(10) External water use

5.0

(11) Total water consumption = (9) + (10) (litres/person/day)