Building energy simulation · IDA ICE · Supply system comparison · KTH MJ2509
Three-part KTH assignment set: policy analysis of India’s built environment decarbonisation pathway; IDA ICE parametric simulation of a university building (heat exchanger, orientation, location); and a systematic comparison of 11 heating and cooling supply configurations on bought energy, primary energy and CO&sub2; emissions.
Evidence dashboard
Which building-energy interventions actually move delivered energy and peak heating load when comfort is held near the same PPD target?
The workflow fixed a comfort-calibrated baseline, varied one physical parameter at a time, then compared full supply configurations using bought energy, primary energy and CO2 emissions as the decision metrics.
Heat recovery was the clearest single intervention: it cut AHU power and district-heating peak sharply, while the supply-system sweep showed that GSHP plus PV could turn bought energy negative under the modelled assumptions.
Delivered energy fell from 160,733 kWh to 118,890 kWh when a heat exchanger was added.
The supply rankings depend on primary-energy factors, climate file, PV export assumptions and system sizing rules. The project is useful evidence because it separates comfort calibration, parametric sensitivity and supply-system comparison.
India’s built environment is experiencing rapid growth driven by urbanisation, but its energy use intensity is high: commercial buildings average 100+ kWh/m²/year compared to 30–70 kWh/m²/year for vernacular buildings. 80% of India’s energy demand is met by coal, oil and solid biomass.
The essay argued that decarbonisation requires action across five areas: strengthening and enforcing the Energy Conservation Building Code (ECBC 2017) and National Building Code (NBC 2016); expanding LEED and GRIHA green building certification; integrating lessons from vernacular architecture (passive cooling, thermal mass, cross-ventilation, natural daylighting); scaling rooftop solar and grid modernisation for rural electrification; and reorienting investment towards retrofitting existing stock rather than only new construction.
Three Indian case studies were analysed: the Infosys Mysore campus (LEED Platinum — 40% more energy-efficient than ASHRAE baseline, 58% water saving, 90% daylit floor area, 10% recycled construction material); the Delhi Metro (carbon-neutral since transitioning to green standards under CDM/Gold Standard, with ~14 million sq ft of Phase-III construction certified to IGBC Green); and the Smart Cities Mission (98–110 cities competing to implement circular-economy and smart-grid principles linked to SDG 11).
The vernacular architecture section analysed Kerala’s Nalukettu typology (central open courtyard, laterite walls, terracotta tiled roof on wooden beams, four-hall layout) as a climate-responsive design model for tropical monsoon conditions, and Rajasthan’s stepwells and havelis as passive cooling precedents for arid climates. The key transferable principles were: orientation along prevailing winds, thermal mass, high ceilings, cross-ventilation, and minimised reliance on mechanical cooling.
The baseline condition was established by adjusting maximum heating and cooling power in IDA ICE to achieve a Predicted Percentage of Dissatisfied (PPD) value of approximately 6%. Maximum power settings were then fixed and individual parameters varied to isolate their effect on AHU power, district heating peak demand and total delivered energy.
Heat exchanger addition was the most impactful single change tested. Recovering heat from exhaust air at 70% effectiveness reduced the ventilation heating load substantially, cutting both AHU power demand and the district heating peak nearly in half.
The reference system uses an oil boiler for heating and a liquid chiller for cooling. Ten alternative configurations were simulated, all evaluated on annual bought energy, primary energy used and CO&sub2; emissions:
Key findings from the 11-configuration sweep:
INL1-4
A fourth assignment in the same course used COMSOL Multiphysics and the COMSOL Application Builder to simulate flow distribution in a branched copper pipe network — representative of a district heating or hydronic distribution system. Pipe diameters were selected, and balance valve loss coefficients were iterated to achieve target mass flow rates across all seven branches.
Selected copper pipe diameters:
COMSOL simulation results after balance valve tuning (all branches converged to approximately 0.37–0.40 kg/s):
The inverse relationship between branch position and required loss coefficient reflects the pressure gradient along the main: branches closer to the supply pump require higher valve resistance to prevent over-flow, while distant branches need lower restriction to maintain target flow. This is the fundamental principle of hydronic balancing.
Relevance
This assignment set demonstrates the full built-environment analysis workflow: policy context (India decarbonisation essay), parametric building physics simulation (IDA ICE INL2), and supply system techno-economic comparison (INL3). The INL3 result that a GSHP + full PV system achieves net-negative bought energy and CO&sub2; is a directly actionable insight for building energy design — it quantifies the PV area threshold between grid dependence and grid contribution.
The IDA ICE tool is industry-standard for building energy certification work in Scandinavia and Northern Europe. Experience using it for parametric sensitivity analysis and supply system selection is directly applicable to building energy consulting, HVAC system design and energy performance contracting roles.