IBPSA BS2023: Student Modeling Competition
Students’ Activity Center (SAC), Tongji University, China
Presenters:
Arjita Gupta
Debanjana Das
Mohammed Umar
Mohi Saxena
CEPT University, India
BACKGROUND
China aims to achieve carbon neutrality by 2060.
(An Energy Sector Roadmap to Carbon Neutrality in China Analysis –IEA, n.d.)
In 2020, the building sector contributed to 48% of the country’s greenhouse gas emissions.
(Zhu et al., 2023)
OBJECTIVE
Achieving a net-zero carbon emission building, while maintaining its exterior architectural design.
SAC, Tongji University | Constraints
• Comfort conditions 18 °C – 26 °C
• Max. CO2 level 1000 ppm
• Additional conditions* Pre-defined
( Ventilation rates, dynamic carbon emission factors, occupancy & equipment schedules ) *
SAC - Axonometric illustration & Section
Atelier Liu Yuyang Architects
01 INTRODUCTION
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Arjita Gupta | Debanjana Das
Mohammed Umar
Mohi Saxena
• Model Geometry
BUILDING MODELING CLIMATE ANALYSIS BUILDING OPTIMIZATION CARBON OFFSETTING
Setup
• Modeling assumptions
• Thermal comfort analysis
• HVAC system optimization
TARGET EUI 70 kW.h/(m2.a) *
• CO2 emission reduction using PV
• Passive strategies identification
• Daylight optimization
Leading value for Commercial office buildings
Standard for energy consumption of building (GB/T 51161-2016)
• Cases/iterations
• PV potential analysis
• Façade optimization (Not In Scope)
WORKFLOW
* 02 METHODOLOGY
Arjita Gupta | Debanjana Das | Mohammed Umar | Mohi Saxena
Tower
BUILDING MODELING
MODEL GEOMETRY
Model performance optimization
THERMAL ZONING
The thermal zoning was divided on the basis of internal heat gains, occupancy schedules, and ventilation requirements.
Tower + Podium
SAC - Energy model
DesignBuilder
SAC
Multi-functional area (excluded from energy & carbon analysis)
Ancillary areas (no HVAC system)
Office Lobby
Restroom/lavatory
Staircase
Typical Plan 1 (for 1F & 2F)
DesignBuilder
Typical Plan 2 (for 3F & above)
GEOMETRY | ZONING | ITERATIONS
03
Arjita Gupta | Debanjana Das | Mohammed Umar
|
Mohi Saxena
=
Eq. SHGC
BUILDING MODELING
PROCESS
Model Verification → Parameters (Input) → Evaluation (Output + Post-processing) → Cases/Iterations
CASE DEFINITION
Base Case | BAU building with VAV system
Base Case
VAV System
Glazing
Case-1 | HVAC Optimization
Lighting control
Case-2 | Dedicated Outdoor Air System
Case-3 | Lighting Optimization
HVAC Design
Case-4 | PV array on podium rooftop
Renewable Energy
Comfort +
Environment
Design Case | Combined case containing optimized parameters of all iterations
Air Quality
Case Definition Matrix
Case 1 HVAC Optimization
Case 2 HVAC + Fresh Air
Case 3
Lighting Control
Case 4 PV Potential
Design Case
GEOMETRY | ZONING | ITERATIONS
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Umar |
04
Arjita Gupta
Debanjana Das
Mohammed
Mohi Saxena
CLIMATE ANALYSIS
THERMAL COMFORT Arjita
| Debanjana
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|
05 THERMAL COMFORT ANALYSIS 0 10 20 30 40 50 60 70 80 90 100 -5 0 5 10 15 20 25 30 35 40 Relative Humidity (%) Outside Dry-Bulb Temperature (oC) Cold and humid Humid Hot and humid 3 2 1 4 7 8 6 9 5 1 Heating & Dehumification 2 Dehumidification
Cooling & Dehumification 4 Heating 5 Thermally Comfortable 6 Cooling 7 Heating & Humidification 8 Humidification 9 Cooling & Humidification
51% hours Heating & Dehumidification 32% hours Dehumidification 17% hours Cooling & Dehumidification
Gupta
Das
Mohammed Umar
Mohi Saxena
3
DBT x RH Annual Graph
CORRELATION OF INDOOR PARAMETERS TO OUTDOOR
VARIABLES AND THEIR IMPACT
impact of each parameter individually on EUI reduction from Base Case EUI = 213 kWh/m2.a
4% 3% 18% 17% 10% 0% 5% 10% 15% 20% System Optimization BMS DOAS Dehumidification COP
OF PERFORMANCE ANALYSIS ELECTRIC LOAD LATEND LOAD TARGET EUI =70 kWh/m2.a HVAC OPERATING SYSTEM | METHODOLOGY Arjita Gupta | Debanjana Das | Mohammed Umar | Mohi Saxena 06 Total Cooling Air Temp. -0.75 Heating Elec. -0.81 Cooling Elec. -0.96 0.77 DBT -0.76 0.88 -0.81 0.76 WBT -0.76 0.88 -0.81 0.76 1 RH Levels 0.84 -0.79 0.97 0.97 Sky Cover 0.79 -0.75 0.92 0.92 0.94 Building RH 0.76 -0.82 0.77 0.77 Total Cooling Air Temp. Heating Elec. Cooling Elec. DBT WBT RH Levels Sky Cover Building RH
METRIC
indoor
on outdoor conditions.
All components and loops of the system require an in-depth analysis to achieve ideal optimization through analysing dependent
parameters
1.00 0.50 0.00 -0.50 -1.00
HVAC INTRODUCTION
CONDITION OUTDOOR CONDITIONS INDOOR PARAMETERS
DESIGN ITERATION
The system was changed to Variable Refrigerant Flow (VRF) in the design case. Realistic iterations which are deployable in the current scenario for the SAC are considered.
MARKET RESEARCH
An assessment for choosing a system based on:
HVAC OPERATING SYSTEM | DESIGN Arjita
| Debanjana
|
Umar |
07 DOAS Recirculation Heat Recovery System Sizing 300kw 150kw COP Cooling: 4 Heating: 4.52 Dehumidification On BMS Fluctuating temp. DOAS No System Sizing 476 kw 207kw COP Cooling 3.3 Heating 3.4 Dehumidification Off BMS No BASE CASE DESIGN CASE Change of system= VRF SYSTEM Base System= RTU VAV reheat unit 213 kWh/m2.a
Gupta
Das
Mohammed
Mohi Saxena
• Capacity • COP • EER • SEER • Type • Market availability
DESIGN CASE BASE CASE
VAV-AIR COOLED
LEGEND:
SUPPLIED REFRIGERANT FLOW
RETURN REFRIGERANT FLOW
SUPPLY HOT WATER
RETURN HOT WATER
SUPPLY FRESH AIR
RETURN FRESH AIR
SUPPLY AIR TO THERMAL ZONE
RETURN AIR FROM THERMAL ZONE
AIR COOLED
VRF
DOAS:
DEHUMIDIFICATION + RECIRCULATION
RESTROOM STAIRCASE
DOAS
SET POINT MANAGER
HEATING AND COOLING COIL
FILTER
CENTRIFUGAL FAN
VRF TERMINAL UNIT
HVAC OPERATING SYSTEM | HVAC SYSTEM EXECUTION
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08
Arjita Gupta | Debanjana Das
Mohammed Umar
Mohi Saxena
TZ: OFFICE
TZ: LOBBY
AHU
AHU BOILER
VFD VFD
LOBBY OFFICE OFFICE
CONCEPTUAL DIAGRAM TO EXPLAIN EMPLOYED SIMULATION
HVAC SCHEMATIC A
HVAC RESULT
Electricity: Total Building Electricity Consumption.
Latent Load: OccupantsAnd Other Internals Gains
WINTER TRANSITION 1 SUMMER TRANSITION 2 WINTER WINTER TRANSITION 1 SUMMER TRANSITION 2 WINTER
HVAC OPERATING SYSTEM | RESULT Arjita
|
| Mohammed Umar |
Saxena 09
Gupta
Debanjana Das
Mohi
ANNUAL BASE CASE ANNUAL DESIGN CASE -45.3% ANNUAL BASE CASE ANNUAL DESIGN CASE -22.4%
VISUAL COMFORT
Daylight Access
Interior Lighting control
Glare Control VISUAL
Visual Comfort: Methodology
COMFORT | INTRODUCTION
10
Arjita Gupta
| Debanjana Das | Mohammed Umar | Mohi Saxena
Daylight study for VISUAL COMFORT
Spatial Daylight Autonomy300/50%
Target Illuminance: A target illuminance of 300 lux should be achieved across 50% of the space of the reference plane for plane 50% of the daylight hours.
Required threshold : 50%
Above threshold : 60.70%
VISUAL COMFORT | sDA
Arjita Gupta | Debanjana Das | Mohammed Umar | Mohi Saxena
Required threshold : 50% Above threshold : 60.70% 1F : 46.98% 2F : 38.21% 3F : 61.08% 4F : 69.66% 5F : 72.06% 6F : 64.15% 7F : 70.94% 8F : 91.51% Legend
11
Blinds usage for VISUAL COMFORT
“GLARE NOT PERCIEVED”
COMFORT | GLARE ANALYSIS
VISUAL
Arjita Gupta | Debanjana Das | Mohammed Umar | Mohi Saxena
GLARE PROBABILITY Without blinds With blinds
12
77% 100%
VISUAL COMFORT
Sensitivity Analysis
Lighting consumption(kWh/m²)
Lighting Control System
Shading Using internal blinds
BASE CASE EUI : 213 (kW.h/m².a)
Base case (without lighting control and shading)
DESIGN CASE EUI : 188 (kW.h/m².a)
Multi lighting controldimming
Multi lighting control off
Shading typelight translucent blinds
WWR >0.7
Lighting consumption(kWh/m²)
0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00
Lighting consumption(kWh/m²)
VISUAL COMFORT | ANALYSIS
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Arjita Gupta
Debanjana Das
Mohammed Umar
Mohi Saxena
11% 10%
13
CARBON EMISSION REDUCTION
PV POTENTIAL ANALYSIS
Winter:
Fig xx : Radiation analysis for different seasons
SHADOW ANALYSIS
627m2 of the podium roof was shaded by the tower for 103 hours
2
According to the architectural drawings, we can use an 1842 m2 area for PV. Out of which 1365m2 of the area was used for PV panels.
=1842 m2
25% of the area is kept free of PV for circulation. The PV power generation potential is, =151.55 x 102 kWh*
The specifications for the Solar Panel considered are based on its efficiency in performing at weaker illuminance levels as well.
Fig xx : Annual Shadow Analysis: ArcGIS
PV POTENTIAL ANALYSIS | INTRODUCTION
| Debanjana
|
Arjita Gupta
Das | Mohammed Umar
Mohi Saxena
14
*Estimated on ArcGIS software Dec-Jan- Feb Transition 1 : Mar-Jun Summer: Jul- Sep Transition 2: Oct- Nov MAX OUTPUT MIN OUTPUT
Daily radiation range : 4 – 8 kWh/m
Podium roof area – Skylight area
Area used for PV
Fig xx : PV panel installation on podium roof
PV PANEL PLACEMENT
REDUCED CO2 EMISSION
The annual CO2 emissions for:
Base Case = 56980kg
-31.2%
Design Case= 39197kg
A nearly 100% reduction in CO2 emissions (annually) is attained.
Summer months (July-September): -13433kg of CO2 emissions, signifying net zero carbon emissions
Winter months (Jan-Feb, Dec): -2804 kg of CO2 emissions, signifying net zero carbon emissions
Transition months (March to June, October to November): -22959 kg of CO2 emissions, signifying net zero carbon emissions
-500 -400 -300 -200 -100 0 100 200 300 400 Jan Jan Jan Jan Feb Feb Feb Mar Mar Mar Apr Apr Apr Apr May May May Jun Jun Jun Jun Jul Jul Jul Aug Aug Aug Sep Sep Sep Sep Oct Oct Oct Nov Nov Nov Nov Dec Dec Dec CO2 Emissions, kg Months CO2 Emissions, kg - Annual Base Case PV Case
PV POTENTIAL ANALYSIS | ITERATION
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Umar |
✓ Base Case - no PV panels, ✓ Final Case - with PV panels
Arjita Gupta
Debanjana Das
Mohammed
Mohi Saxena
15
Fig xx : Comparison of CO2 Emission of base case and design case
ELECTRICITY EXPORTED FROM PV SYSTEM TO GRID
Electricity exported to the grid for
Summer months : 42kWh/m2
Winter months : 23kWh/m2
Transition months : 70 kWh/m2
Solar battery systems are used in the design to store the excess energy from the PV system Transition Months
Electricity consumed Electricity generated
PV POTENTIAL ANALYSIS | RESULT
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26.61 25.30 42.12 -41.67 -22.99 -70.17 -80 -60 -40 -20 0 20 40 60 Summer months Winter months Tranition months Electricity ,kWh/m 2 Months
Arjita Gupta
Debanjana Das
Mohammed Umar
Mohi Saxena
Annual Electrical consumption & generation
16
EUI REDUCTION BY DIFFERENT METHODS
Iterations for Optimization
CONCLUSION Arjita Gupta | Debanjana Das | Mohammed Umar | Mohi Saxena 17 213.13 139.45 124.67 120.31 87.71 89.92 71.45 0 25 50 75 100 125 150 175 200 225 Base Case_VAV VRF system System Optmization BMS DOAS DOAS+ Dehumidification Lighting control EUI (kWh/m 2 .yr)
66% 57% 58% 43% 41% 35% RESULT
WINNER
Team CEPT
