REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Bruxelles, March 8, - - PowerPoint PPT Presentation

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS

Bruxelles, March 8, 2012

S.P. Corgnati*, E. Fabrizio§, M. Filippi*

* Politecnico di Torino

§ University of Torino

WHY REFERENCE (BENCHMARK) BUILDING MODELS ?

COST OPTIMAL POLICY of the EPBD (European Performance of

Buildings Directive) recast 2010/ 31/ EU for the definition of the targets of nearly-zero energy buildings. Draft working document on supplementing Directive 2010/ 31/ EU

• 1. Selection of reference (benchmark) buildings
• 2. Definition of energy saving measures for construction
• 3. Definition of energy saving measures for technical systems
• 4. Energy calculations (energy requirements)
• 5. Economic calculations (global cost)
• 6. Sensitivity analyses and finding of the cost-optimal value

What are nearly-zero energy buildings?

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS 1.

• 2. & 3.

4. 6.

The methodology

5.

What is a Reference Building?

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Step 1 Reference Buildings Step 1 Reference Buildings

“building characterized by, and representative of, their functionality and geographic location, including indoor and outdoor climate conditions”

[EPBD recast-Guidelines]

Each Member State has to define A SET OF REFERENCE BUILDINGS:

• 2 for existing buildings;
• 1 for new construction.

Energy Performance of Buildings Directive Recast (EPBD recast, 2010/ 31/ EU) BUILDING CATEGORIES:

• Single-family house;
• Multi-family house;
• Office building;
• Non- residential buildings.

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS

Approaches to a Reference Building construction

Handbook, manuals, experience, references Building stock Known building stock Expert Example RB Statistical manipulation separated results Real RB …. Theoretical RB aggregated results Fictional building Input data Processing Model Problem of the true correlations

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS

Approaches to a Reference Building

Step 1 Reference Buildings Step 1 Reference Buildings REAL BUILDING: a real existing building, with average characteristics based on

statistical analysis.

EXAMPLE BUILDING: On the basis of experts’ assumption it is the most probable of a

group of buildings, within a selected location and age.

THEORETICAL BUILDING: A statistical composite of the features found within a

category of buildings in the stock (ECBSdefinition).

Empirical Data Expert Assumptions Statistical Data

Step 1 Reference Buildings Step 1 Reference Buildings REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS ASSUMPTIONS:

• 1. System Boundary

Step 1 Reference Buildings Step 1 Reference Buildings REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS ASSUMPTIONS:

• 2. Metrics

GLOBAL COST

consumable items cyclical regulatory cost utilities (except energy cost)

global cost

initial investment cost annual cost disposal cost

running cost

professional fees (e.g. project design) construction of assets taxes (if applicable)

• thers (e.g. project

contingencies)

energy cost

• perational cost

maintenance cost

periodic substitute investment

• f a building element

result of energy performance calculation energy tariffs

replacement cost

adjustments inspections cleaning repair insurance taxes (if applicable)

• thers

consumable items cyclical regulatory cost utilities (except energy cost)

global cost

initial investment cost annual cost disposal cost

running cost

professional fees (e.g. project design) construction of assets taxes (if applicable)

• thers (e.g. project

contingencies)

energy cost

• perational cost

maintenance cost

periodic substitute investment

• f a building element

result of energy performance calculation energy tariffs

replacement cost

adjustments inspections cleaning repair insurance taxes (if applicable)

• thers

Cost categorisation according to the Framework

Methodology (EPBD guidelines)

Standard EN 15459

Step 1 Reference Buildings Step 1 Reference Buildings REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS ASSUMPTIONS:

• 2. Metrics

GLOBAL COST

Lifecycle

Long Lifecycle are not recommended as it is difficult to predict the interest rates and energy

• prices. 50 years

Standard EN 15459

1)all the costs refer to the starting year by applying appropriate discount rate coefficients

• r present value factors;

2)the global cost is the sum of the global costs of initial investment costs, periodic and replacement costs, annual costs and energy costs and the global cost of the final value (negative).

Discount rate?

Real interest rate (2,5%) General inflation rate / Inflation rate of energy sources /

Lifespan periods of building elements

Step 1 Reference Buildings Step 1 Reference Buildings REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS ASSUMPTIONS:

• 3. The boundary conditions: constant parameters

Climate Building envelope Building equipment Operation & Maintenance Occupant behavior Indoor environmental conditions

Building Performance Energy Needs

STATE OF THE ART

World:

Benchmark Building models developed by US Department of Energy (DOE)

Europe:

• TABULA project on the definition of residential building typology for energy investigations;
• ASIEPI project
• BPIE Principles for nearly-zero energy buildings (single-family house, multi-storey building)
• Rehva Task Force: “Reference Building for energy performance and cost optimal analysis”.

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Step 1 Reference Buildings Step 1 Reference Buildings

Principles and Application fields of TABULA project Collected national representative single-family houses by ASIEPI project

RESEARCH ACTIVITIES BY TEBE GROUP

Definition of three Reference Buildings:

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Step 1 Reference Buildings Step 1 Reference Buildings

A Multi-family residential building (Source: TABULA project) A Medium Office Building (Source: ENEA survey over the definition

• f a representative Italian office building for three main areas)

A Large Office Building as result of a customization of the DOE large office building to Italian context (legislative requirements, constructions, climate) Reference buildings collected by age: 1 2 3

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Step 1 Reference Buildings Step 1 Reference Buildings MULTI-FAMILY REFERENCE BUILDING

Typical floor plan, Multi-family building.

BUILDING

Geometry

External dimensions 12,60 x 37,50 m Gross Floor Area 472,50 m2 Total Gross Area 1336 m2 Room height 3,10 m N-E Façade Exterior wall area 170,10 m2 S-E Façade Exterior wall area 383,70 m2 Window area 122,58 m2 S-O Façade Exterior wall area 170,10 m2 N-O Façade Exterior wall area 326,30 m2 Window area 94,06 m2

Envelope Components

Opaque elements Exterior Wall 0,52 W/ m2K Flat ceiling under the roof 2,02 W/ m2K Slab towards non conditioned basement 1,35 W/ m2K Transparent Elements Window 3,51 W/ m2K

SYSTEM

Heating system

Gas boiler with radiators. The setpoint temperatures are 20°C from 7 a.m. until 8 p.m., and 18°C during the remaining hours.

Ventilation

The infiltration rate is 0,5 ACH and is constant during all days.

OPERATION

Internal Gains

People 0,04 person/ m2 Appliance (incl. Lighting) 4 W/ m2

Real Building

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Step 1 Reference Buildings Step 1 Reference Buildings MEDIUM OFFICE REFERENCE BUILDING

BUILDING Geometry

External dimensions 16x30 m Gross Floor Area 480 m2 Total Gross Area 2400 m2 Height 2,9 m Northern Façade Exterior wall area 278 m2 Window area 157,50 m2 Southern Façade Exterior wall area 278 m2 Window area 157,50 m2 Western Façade Exterior wall area 232 m2 Window area 140 m2 Eastern Façade Exterior wall area 232 m2 Window area 140 m2

Envelope Components

Opaque elements Exterior Wall 0,761 W/ m2 K Roof 0,828 W/ m2 K Underground slab 0,516 W/ m2 K Transparent Elements Window 3,19 W/ m2 K

SYSTEM HVAC

4 pipes fancoils with outside air

Heating system

Gas boiler (80°C)

Heating setpoint

21,5°C from 5 a.m. until 6 p.m., and 15°C in remaining hours, during week days.

Cooling system

Water-cooled chiller

Cooling setpoint

26°C from 5 a.m. until 6 p.m. during week day; Turn off during the remaining hours.

Ventilation

11 l/ s per person, Air flow is assumed to be constant from 5 a.m. until 6 p.m during week days.

OPERATION Internal Gains

People The occupancy rate for offices id 0,06 person/ m2. Lighting 13 W/ m2 during working days. A 0,5 percentage is assumed during weekends and night time for security systems. Equipm ent 10 W/ m2 during working days.

Axonometric View, Medium office building. Typical floor plan, Medium office building.

Theoretical Building

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Step 1 Reference Buildings Step 1 Reference Buildings LARGE OFFICE REFERENCE BUILDING

Axonometric View, Large office building. Thermal zones, Large office building.

Exemplar Building

BUILDING

Geometry

External dimensions 48x73 m Gross Floor Area 3563 m2 Total Gross Area 46’320 m2 Floor to Floor Height 2,74 m Northern Façade Exterior wall area 2090 m2 Window area 1391 m2 Southern Façade Exterior wall area 2090 m2 Window area 1391 m2 Western Façade Exterior wall area 1389 m2 Window area 927 m2 Eastern Façade Exterior wall area 1389 m2 Window area 927 m2

Envelope Components

Opaque elements Exterior Wall 0,309 W/ m2 K Roof 0,248 W/ m2 K Underground slab 0,638 W/ m2 K Transparent Elements Window 1,1 W/ m2 K

SYSTEM

HVAC

Multi-zone VAV with fancoils

Heating system Gas boiler (80°C) Heating setpoint

21°C from 5a.m. until 7p.m., and 15,6°C in remaining hours, during weekdays.

Cooling system 2 Water cooled chillers Cooling setpoint 24°C from 5 a.m. until 6 p.m. during weekdays; 30 °C during the remaining

hours.

Ventilation

0,10 ACH. Air flow is assumed to be constant from 6 a.m. until 10 p.m during weekdays.

OPERATION

Internal Gains

People The occupancy rate for offices id 0,06 person/ m2. Lighting 15 W/ m2 during weekdays. Equipment 10 W/ m2 during weekdays.

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Step 2&3 Measures Step 2&3 Measures PACKAGES OF MEASURES

Multi-family Reference building

10 PACKAGES OF MEASURES concerning the building envelope NON-HOMOGENEOUS PACKAGES: measures regarding only to a few building elements. HOMOGENEOUS PACKAGES: measures applied similarly to all building elements.

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS EXTERIOR WALL THERMAL INSULATION Step 2&3 Measures Step 2&3 Measures

Multi-family Reference building

Standard Requirement Package Energy saving measure datasheet:

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS Step 2&3 Measures Step 2&3 Measures

Multi-family Reference building

ECONOMIC EVALUATION OF THE MEASURE

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS

Step 5 Energy Model Step 5 Energy Model

DYNAMIC ENERGY SIMULATION

Multi-family Reference building

EnergyPlus

Modeling Simulation Results

Thermal zones Input data

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS SIMULATION RESULTS: HEATING ENERGY DEMAND

Multi-family Reference building

20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 180,000 1 2 3 4 5 6 7 8 9 10

kWh Package of Measures

Heating demand Envelope losses Ventilation losses

Step 5 Energy Model Step 5 Energy Model

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS

Step 6 Cost Optimal Analysis Step 6 Cost Optimal Analysis

COST-OPTIMAL LEVEL:

(with appliances) (without appliances) Multi-family Reference building

300 350 400 450 500 550 600 25 50 75 100 125 150

Primary energy [kWh/m2]

RB 1 2 3 4 5 6 7 8 9 10 300 350 400 450 500 550 600 25 50 75 100 125 150 175

Global Cost [€/m2]

Primary energy [kWh/m2]

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS

OPEN QUES TIONS

• How to select the packages of energy saving measures. With n different

measures that have k steps of varition, the number of combinations becomes kn Not all the combnations of measures are feasible! The number reduces.

• How to select the correct economic scenario that affects the global cost

calculation: inflation rate inflation rate of energy sources interest/ discount rate lifetimes global lifespan

• How take into account the spatial variability (locations, climate)

REFERENCE BUILDINGS FOR COST-OPTIMAL ANALYSIS

REFERENCES

Ballarini, I. Corgnati, S.P . Corrado, V. Talà, N. Definition of building typologies for energy

investigations on residential sector by TABULA IEE-project: application to italian case studies, In: RoomVent 2011, Trondheim, 19-22 J

une 2011. Ballarini I., Corgnati S.P ., Corrado V., Tala’ N. (2011) Improving energy modeling of large

building stock through the development of archetype buildings., In: Building Simulation

2011, S ydney (Australia), 14-16 November 2011. pp. 2874-2881

• E. Fabrizio, D. Guglielmino, V. Monetti, Italian benchmark building models: the office

building, in V. Soebarto, H. Bennetts, P

. Bannister, P .C. Thomas, D. Leach (a cura di), “Driving better design through simulation”, IBPSA Australia & AIRAH, Melbourne, 2011, pp. 1981- 1988 (ISBN 978-0-646-56510-1).

• C. Becchio, D. Guglielmino, E. Fabrizio, M. Filippi, Whole cost analysis of building envelope

technologies according to the European Standard EN 15459, Climamed ’11 VI Congreso

Mediterraneo de Climatizacion, Madrid 2-3 giugno 2011, ATECYR, pp. 291-306 (ISBN 978- 84-95010-41-4).

Thank you for your attention