energy performance simulation of a residential...

Energy performance simulation of a residential building

Dr. Norbert HarmathyDr. Zoltán Magyar

48. Međunarodni kongres i izložba o KGH, Beograd, 6–8.12.2017.48th International HVAC&R Congress and Exhibition, Belgrade, 6–8 Dec. 2017

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Budapest University of Technology and EconomicsDepartment of Building Energetics and Building Service Engineering


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OutlineBuilding energy performance modelling

1. INTRODUCTION - MOTIVATION

2. RESEARCH METHODOLOGY

3. BUILDING ENERGY PERFORMANCE SIMULATION

4. RESULTS AND DISCUSSION

5. CONCLUSION


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1. Introduction - motivationThe purpose of the research was to formulate a preferable solution for the climate conditions of Budapest.

In order to define the energy saving potential three building structures:1.KLH cross laminated timber, 2.Wienerberger Porotherm and 3.Ytong AAC construction.


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1. Introduction - motivationAll multi-zone models contain detailed information that influences the heating and cooling requirements, such as:

- internal heat sources, - operation schedules, - air temperature adjustment, - air change rate, - occupants.


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2. Research methodologyThe annual heating and cooling demands of the 15 scenarios were explored through the following ten steps:1. Geometric modelling of the reference building and

development of a simulation base multi-zone 3D model,

2. Assignment of thermal zones, space types to the multi-zone energy model,

3. Multiplying the multi-zone model and designing two different glazing ratios to the building envelope,

4. Exporting the multi-zone energy model and assigning construction set and building material properties,


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2. Research methodology5. Assigning internal loads and heat gains to the

imported energy model,6. Assigning glazing type and parameters,7. Defining operation and maintenance, assigning intervals and comfort parameters, 8. Model conversion to numerical IDF data,9. Performing multiple simulations on annual basis with hourly time-steps for the climate data of Budapest, 10. Evaluating the annual energy performance and determining the adequate building construction and glazing parameters.


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3. Building energy performance simulation

Multi-zone thermal model The first phase included the modelling of the multi-zone thermal model of the building, since the function of the building represents different zone divisions. The multi-zone thermal model was divided into five thermal zones depending from its internal gains and position: •Zone 1 bedroom, •Zone 2 living room, dining room and kitchen, •Zone 3 corridor, •Zone 4 bathroom and •Zone 5 was the second room.


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Climatological dataThe location of the building is Budapest, Latitude = 47.433°, Longitude = 19.183°, Altitude = 140 m and Climatic zone = III, 3.


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3. Building energy performance simulation

Simulated construction typesThe research scope was to determine and evaluate the building’s energy performance for three different construction types:

1.KLH cross laminated timber

2.Wienerberger Porotherm brick construction

3.Ytong autoclaved aerated concrete (AAC)

Residential building


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KLH cross laminated timber


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Wienerberger Porotherm block construction

The energy simulation was performed for three variations of Porotherm wall construction, which are the following:

1.Exterior wall 1; PTH block Clima Profi, 38cm

2.Exterior wall 2; PTH block Clima Profi, 2 x 38cm

3.Exterior wall 3; PTH block Clima Profi, 38cm + Expanded Polystyrene insulation, 14cm


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Wienerberger Porotherm block construction


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Ytong autoclaved aerated concrete (AAC)


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Envelope glazingThe applied glazing constructions in the simulation were tri-pane windows with Argon gas insulation and low-E layer. The first window construction had the following parameters:• Overall thermal conductivity (U-value) 1.0 W/m2K• Solar heat gain coefficient (g –value) 0.34• Visible light transmittance (τ - value) 0.63The second window construction had the following parameters:• Overall thermal conductivity (U-value) 0.7 W/m2K• Solar heat gain coefficient (g –value) 0.26• Visible light transmittance (τ - value) 0.52In the simulation two window to wall glazing ratios (WWR) were applied (85% and 50%), resulting in a total number of 15 formulated simulation scenarios.


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Dynamic simulation input data Buildings occupancy is the act of occupying spaces during a period of time. In the following energy simulation, the occupancy is defined according to the:• Occupancy intensity in the function of occupied period, and • People activity in the function of the occupied period.

Default occupancy schedule Default lighting schedule


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4. Results and discussionThe research included 15 simulations in total and the annual energy performance of all scenarios were compared and evaluated which were the following:• Scenario 1: KLH cross laminated timber construction, glazing 1, WWR 85%• Scenario 2: KLH cross laminated timber construction, glazing 2, WWR 85%• Scenario 3: KLH cross laminated timber construction, glazing 2, WWR 50%• Scenario 4: Wienerberger Porotherm block construction with 38cm PTH

Clima Profi exterior wall, glazing 1, WWR 85%• Scenario 5: Wienerberger Porotherm block construction with 38cm PTH


Clima Profi exterior wall, glazing 2, WWR 50%• Scenario 7: Wienerberger Porotherm block construction with 2*38cm PTH

Clima Profi exterior wall, glazing 1, WWR 85%


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4. Results and discussion• Scenario 8: Wienerberger Porotherm block construction with 2*38cm PTH

Clima Profi exterior wall, glazing 2, WWR 85%• Scenario 9: Wienerberger Porotherm block construction with 2*38cm PTH


Clima Profi exterior wall + 14cm EPS board insulation, glazing 1, WWR 85%• Scenario 11: Wienerberger Porotherm block construction with 38cm PTH

Clima Profi exterior wall + 14cm EPS board insulation, glazing 2, WWR 85%• Scenario 12: Wienerberger Porotherm block construction with 38cm PTH

Clima Profi exterior wall + 14cm EPS board insulation, glazing 2, WWR 50%• Scenario 13: Ytong AAC with 40cm Thermo block exterior wall, glazing 1, WWR 85%• Scenario 14: Ytong AAC with 40cm Thermo block exterior wall, glazing 2, WWR 85%• Scenario 15: Ytong AAC with 40cm Thermo block exterior wall, glazing 2, WWR 50%


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4. Results and discussionEnergy performance of Scenarios 1-3, KLH cross laminated timber construction


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4. Results and discussionEnergy performance of Scenarios 4-12, Wienerberger Porotherm brick construction


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4. Results and discussionEnergy performance of Scenarios 13-15, Ytong ACC construction


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4. Results and discussionThe low heat storage capacity has a negative effect on the heating energy demand. The results demonstrate that if the WWR is reduced from 85% to 50% and the preferred three-layer windows heat transfer coefficient reduced from 1.0 W/m2K to 0.7 W/m2K, then the annual cooling energy demand can be reduced approximately 42% (28 kWh/m2/year).

In contrary, the heating energy consumption will be higher by 20% (6 kWh/m2/year), because of reduced internal solar energy gains during the winter period. Thus, the total annual energy reduction equals 22 kWh/m2/year.


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4. Results and discussionThe model with 38cm PTH exterior wall structure had similar

annual energy demands com-pared with the KLH structure. The energy performance of Scenario 3 (KLH, WWR 50%) and Scenario 5 (Porotherm, WWR 85%) is identical, 76 kWh/m2/year.

The energy performance of the Porotherm 2 x 38cm (76cm) block construction had a slightly lower energy demand according to the single 38cm thick wall model. However, the lowest energy demand was assessed in scenario 7 it requires only 15% (9 kWh/m2/year) less cooling energy according to the 38cm PTH structure, while the investment in the exte-rior walls would double. The results would not be cost effective in this case. Finally, the model with PTH block walls of 38cm + 14cm EPS thermal insulation provided the same energy efficiency, as the previous 76cm thick PTH block wall.


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4. Results and discussionComparison


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5. ConclusionThe final decision of the most preferable construction type from the energy efficiency point of view was the Porotherm construction with the following characteristics:Construction:

• Exterior wall: PTH block 38cm + 14cm EPS thermal insulation• Roof system: PTH 60/17 + 4cm C20/25 concrete layer +

24cm thermal insulation plateGlazing: Tri-pane insulated glass Argon filled, low-e coating

• heat transfer coefficient, U = 0.7 W/m2K• solar heat gain coefficient, g = 0.26• visible light transmittance factor τ = 0.52• glazing ratio, 50%

ACKNOWLEDGEMENTThis article is linked to the “Solar Decathlon Competition for investigating efficient utilization of the BME ODOO project's professional objectives”. The project is supported by the New Széchenyi Plan ED_13-1-2013-0005 program.

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