Modelling of heat pumps installed in multi-family buildings for space heating and domestic hot water

The global transition to low-carbon energy systems necessitates innovative solutions for space heating and domestic hot water (DHW) in residential buildings, particularly in multi-family buildings (MFBs), which account for a significant share of greenhouse gas emissions. This thesis investigates the feasibility, efficiency, and environmental impact of heat pump (HP) systems in MFBs compared to conventional gas condensing boilers (GB) and hybrid (GB+HP) configurations, with a focus on overcoming technical, economic, and practical barriers to adoption. Using dynamic simulations in EnergyPlus and OpenStudio, three primary scenarios were evaluated across non-insulated (NIB) and insulated buildings (IB): (1) a baseline gas boiler system, (2) a standalone air-to-water heat pump, and (3) a hybrid system combining both technologies. The study incorporated variable operational modes (intermittent, setback, continuous) and supply temperature strategies (fixed vs. weather-compensated) to assess energy consumption, thermal comfort, and CO₂ emissions. Key findings demonstrate that heat pumps in insulated buildings reduce CO₂ emissions by 35.3% compared to gas boilers, achieving a seasonal coefficient of performance (SCOP) of 2.20–2.43. Insulation slashed heating demand by 81.6% in gas boiler systems and 80.2% in HP systems, underscoring its critical role in decarbonization. Hybrid systems, while effective in NIB (5.4% demand reduction), offered limited benefits in IB due to boiler inefficiencies during peak loads. Weathercompensated supply temperatures improved HP efficiency by 10.4% in NIB, while intermittent operation reduced energy use by 7.5–11.2% across systems. Secondary losses due to radiators and hot water tank standby heat loss were also examined, with estimated contributions of 8–12% of delivered heat for radiators and 5–7% of total energy input for storage tanks. These losses underscore the importance of system optimization beyond primary energy demand reduction. The study highlights the importance of building retrofits as a prerequisite for HP viability and positions hybrid systems as transitional solutions for non-insulated buildings. Policy recommendations emphasize incentivizing insulation upgrades, dynamic control strategies, and phased gas boiler replacements. This work provides actionable insights for policymakers, engineers, and building owners, demonstrating that heat pumps—when paired with insulation—are a cornerstone for achieving energy efficiency and climate neutrality in MFBs. The results advocate for integrated approaches combining building envelope improvements, advanced heat pump technologies, and adaptive operational strategies to accelerate the decarbonization of urban heating systems.