Computer-aided decision supporting tool for nearly...

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Computer-aided decision supporting tool for nearly Zero

Energy Building renovation

Suzana Domjan, Ciril Arkar, Sašo Medved

Faculty of Mechanical Engineering, Laboratory for Sustainable Technologies in Buildings,

University of Ljubljana, Slovenia

23rd September 2016, Manchester, UK Third International Conference „Global dwelling“

TOOL DEVELOPMENT BACKGROUND

Final energy consumption, EU-28, 2014 (% of total)(source: Eurostat (online data code: nrg_100), 2016)

According to EPBD Recast (Directive 2010/31/EU) Member States shall ensure

that:

(9.1.a) by 31 December 2020, all new buildings are nearly zero energy buildings;

and

(9.1.b) after 31 December 2018, new buildings occupied and owned by public

authorities are nearly zero-energy buildings.

Nearly zero-energy building (nZEB) means a building that has (2.2):

very high energy performance,

nearly zero or very low amount of energy required should be covered to a very

significant extent by energy from renewable sources, including

energy from renewable sources produced on-site or nearby.


(9.2 & 9.3) Member States shall ensure detailed application in practice of the

definition of nearly zero-energy buildings, reflecting their national, regional or

local conditions, and including a numerical indicator of primary energy use

expressed in kWh/m2 per year. Primary energy factors used for the

determination of the primary energy use may be based on national or regional

yearly average values and may take into account relevant European standards.

Status of nZEB definition for new

buildings, as of April 2015 (source: BPIE, 2015)

Building type

Max. primary energy use(kWh/m2a)

Min. share of RES (%)

Newbuilding

Major reconstruction

RER (REHVA definition)

Single family building

85 105 50

Multi familybuilding

80 90 50

Non-residential building

55 80 50

Indicators for nZEB (Slovenia)(source: nZEB AP, 2014)


Directive 2009/125/EC (recast) establishing a framework for the setting of

ecodesign requirements for energy-related products points out:

(3) Energy-related products account for a large proportion of the consumption of

natural resources and energy in the Community.

(4) Many energy-related products have a significant potential for being

improved in order to reduce environmental impacts and to achieve energy

savings through better design which also leads to economic savings for

businesses and end-users. In addition to products which use, generate, transfer,

or measure energy, certain energy-related products, including products used

in construction such as windows, insulation materials, or some water-using

products such as shower heads or taps could also contribute to significant

energy savings during use.

(7) Action should be taken during the design phase of energy-related

products, since it appears that the pollution caused during a product’s life cycle

is determined at that stage, and most of the costs involved are committed then.


According to Commission Delegated Regulation (EU) No 244/2012

supplementing EPBD on the energy performance (2):

It is the responsibility of Member States to set minimum energy performance

requirements for buildings and building elements. The requirements must be set

with a view to achieving cost-optimal levels.

National minimum energy performance requirements should not be more than

15 % lower than the outcome of the cost-optimal results of the calculation

taken as the national benchmark. The cost-optimal level shall lie within the range

of performance levels where the cost-benefit analysis over the lifecycle is

positive.

0

50

0 20 40 60 80 100 120 140 160 180

100

Q' (kWh/m a)p

2

15%

spe

cifi

c co

sts

in a

lif

e-c

ycle

(€

/m)

2

150

200

250

300


energy environment cost

TOOL

(source: DGNB, 2015)


energy environment cost

TOOL

(source: DGNB, 2015)

Etool

BEPT LCAT


TOOL

BEPT

LCILCIALCCA

list of „LCA materials“

in database;reference quantity:1 m3 or 1

m2

list of „LCA windows/

doors“;reference quantity:

1 m2

Building envelope

Appliances and systems

Energy carriers

Building energy performance tool

LCILCIALCCA

data in database added for all energy

carriers

reference quantity:

1 kWh/a of final

energy

LCI, LCIA, LCCA

heating systemreference

quantity: heat generator

power

solar heating system

reference quantity: solar collectors area, heat exchanger

volume

PV systemreference

quantity: PV panels area

TOOL

BEPT LCAT - Etool

LCILCIALCCA

list of „LCA materials“

in database;reference quantity:1 m3 or 1

m2

list of „LCA windows/

doors“;reference quantity:

1 m2

Building envelope

Appliances and systems

Energy carriers

LCEA - RP

Building energy performance tool Life cycle assessment tool

LCILCIALCCA

data in database added for all energy

carriers

reference quantity:

1 kWh/a of final

energy

LCI, LCIA, LCCA

heating systemreference

quantity: heat generator

power

solar heating system

reference quantity: solar collectors area, heat exchanger

volume

PV systemreference

quantity: PV panels area

LCIA

LCCAEconomic

parameters

Selection of assessment

method

Desired energy class

Existingbuilding

Newbuilding

Referenceproject (RP)

Presentproject (PP)

Au

tom

atic

sta

rt o

f LC

AT

and

dat

a tr

ansf

er

Des

ign

er in

pu

t

Report

LCEA - PP

LCA period

METHODS – ENERGY ASSESSMENT (LCEA)

Two time intervals are common for energy performance calculations:

Monthly methods can be performed with simple tools taking into account

average monthly data of ambient and indoor temperatures and solar radiation.

Hourly methods can be performed using sophisticated computer tools that

analyze quasi-unsteady heat transfer in building elements and dynamic thermal

response of the building and use hourly meteorological data and hourly profiles

of operation, occupancy and internal heat gains building use.

METHODS – ENERGY ASSESSMENT (LCEA)

heating,ventilation,hot water,

cooling,air-

conditioning,lightning

Qf, i

QNH

QNC

Qp

CO2

actual energy flow

computational energy flow

Regardless which method is used, indicators are determinate in three steps that

are in opposite direction comparing to actual energy flows.

Energy efficiency indicators for buildings

are calculated at three levels:

energy needs for heating QNH and

cooling QNC are compared to national

defined maximum allowed values;

the values are expressed as yearly

specific needs per 1 m2 of building

conditioned area;

determination of delivered energy Qf

(energy supplied to the building through

the last market agent); consumption of each energy carrier needed for operation

of installed systems are calculated based on energy needs and properties of

installed system components;

knowing the type and amount of each energy carrier needed for building

operation, primary energy needs Qp and CO2 emissions are calculated as

specific values calculated per 1 m2 of building conditioned area.

METHODS – ENVIRONMENTAL ASSESSMENT (LCIA)

For environmental assessment we decided to use Type III Life-cycle data

declarations (ISO 14025, EN 15804). They present the environmental

performance of a product to enable objective comparisons between products

fulfilling the same function. EPDs are:

based on independently verified life-cycle

assessment (LCA) data, life-cycle inventory

analysis (LCI) data, converted LCI data to

reflect the life-cycle impact assessment

(LCIA) of a product or information modules;

developed using predetermined

parameters;

subject to the administration of a

programme operator, such as a company

or a group of companies, industrial sector

or trade association, public authorities or

agencies, or an independent scientific body

or other organization.

Example of Environmental Product Declaration

(source: construction-environment.com)

Raw materials(A1-A2)

Manufacturing(A3)

Logistics(A4)

Installation(A5)

Building liftime(B1-B7)

End-of-life(C1-C4)

Recycling(D)

METHODS – ENVIRONMENTAL ASSESSMENT (LCIA)

(source: thinkstep.com, 2016)

Environmental impact parameters:

• Global Warming Potential (GWP, kg eqCO2),

• Ozone Depletion Potential (ODP, kg eqCFC-11),

• Acidification Potential (AP, kg eqSO2),

• Eutrophication Potential (EP, kg eq(PO4)3-),

• Photochemical Ozone Creation Potential

(POCP, kg eqC2H4),

• Abiotic Depletion Potential – Elements (ADPE, kg eqSb),

• Abiotic Depletion Potential – Fossil (ADPF, MJ).

Database in E-tool at the time covers A1-A3 stages

of life-cycle, but it can be expanded by user.

Different approximation polynoms were used for different building elements.

For example GWP for windows:

or ODP for heat generators or heat pumps:

𝐺𝑊𝑃𝑤 = 𝐴𝑤 ∙ 𝑓𝑔 ∙ 𝐺𝑊𝑃𝑔 +𝐴𝑤 ∙ 1 − 𝑓𝑔

𝑑𝑓∙ 𝐺𝑊𝑃𝑓 + 𝐺𝑊𝑃𝑠 kg eqCO2

glass frame spacer

𝑂𝐷𝑃 = 𝑎0 + 𝑎1 ∙ 𝑃 + 𝑎2 ∙ 𝑃2 kg eqCFC−11

nominal power

METHODS – COST ASSESSMENT (LCCA)

Cost assessment of measures follows the Delegated Regulation (EU) No

244/2012, Annex I Cost-optimal methodology framework:

where are:

t calculation period

Cg(t) global cost (referred to starting year t = 0) over the calculation period

CI initial investment costs for measure or set of measures j

Ca,i(j) annual cost during year i for measure or set of measures j

Vf,t(j) residual value of measure or set of measures j at the end of the

calculation period (discounted to the starting year t = 0)

Rd(i) discount factor for year i based on discount rate r

p number of years from the starting period

r real discount rate

𝐶𝑔 𝜏 = 𝐶𝐼 +

𝑗

𝑖=1

𝜏

𝐶𝑎,𝑖 𝑗 ∙ 𝑅𝑑 𝑖 − 𝑉𝑓,𝜏(𝑗)

𝑅𝑑 𝑝 =1

1 +𝑟100

𝑝

METHODS – COST ASSESSMENT (LCCA)

Similar approximation polynoms were used for different building elements as at

environmental assessment.

Example for windows:

or solar collector and heat storage:

Price determination for windows with a wooden frame

and a two-layer glazing, depending on the hydraulic

diameter of the window

𝐶𝐼 = 𝑏0 + 𝑏1 ∙ 𝑑𝑤,𝐻 = 𝑏0 + 𝑏1 ∙4 ∙ 𝐴𝑤𝑂𝑤= 𝑏0 + 𝑏1 ∙

4 ∙ 𝐴𝑤

1 − 𝑓𝑔 ∙ 𝐴𝑤𝑑𝑓

+ 4 ∙ 𝑑𝑓

EUR

𝐶𝐼 = 1.25 ∙ 𝑏1 ∙ 𝐴𝑆𝐶 EUR 𝐶𝐼 = 𝑏0 + 𝑏1 ∙ 𝑉𝐻𝑆 + 𝑏2 ∙ 𝑉𝐻𝑆2 EUR

TOOL – ENERGY ASSESSMENT (LCEA)

TOOL – ENVIRONMENTAL ASSESSMENT (LCIA)

TOOL – COST ASSESSMENT (LCCA)

STUDY CASE – OPTIMIZATION OF MULTI-FAMILY BUILDING ENVELOPE REFURBISHMENT

Reference project: building without

thermal insulation and old wooden

windows (Uw = 3.0 W/m2K).

Energy needed for heating:

Q'NH = 147.7 kWh/m2a

District heating

Conditioned area: 1,950 m2

LCA period: 30 years

Cost optimization of the windows replacement shows that

windows with double glazing are more cost effective and

provide the same reduction in specific primary energy

needed for the building operation. Macroeconomic

greenhouse gas emissions costs indicator also gives

priority to this technology.

Thermal insulation thickness optimization on the basis of

the criteria of cost-effectiveness in the life-cycle (30 years

for residential buildings).

The optimum thickness of 25 cm was achieved at maximum

cost saving in 30 years (52 EUR/m2 in 30 years).

FUTURE

In future we plan to expand E-tool with environmental indicators that are

currently not commonly represented in Environmental Product Declarations,

such as emissions of particular matter.

We would also like to expand the software with database on services and

maintenance that could be selected by user, when applicable.

From research point of view we would like to integrate cost evaluation of the

indoor environment quality in terms of health, productivity and well-being.

This project is funded with support from the European Commission (Project number 539369-LLP1-

2013-1-ES-ERASMUS). This publication reflects the views only of the authors, and the Commission

cannot be held responsible for any use which may be made of the information contained therein.

Thank you for your attention !

If you would like more information about the content of this

presentation please contact:

[email protected]

[email protected]

or visit our web site

www.oikonet.org

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