Simulation-based heat pump system design and optimization for multi-apartment buildings
The progress of the energy transition in the building sector remains insufficient, particularly for existing multi-apartment buildings where the replacement of fossil-based heating systems with renewable alternatives such as heat pumps (HP) is still limited. Besides financial barriers and the owner - tenant dilemma, several technical challenges hinder widespread adoption. These include ensuring appropriate system sizing, maintaining acceptable flow temperatures for efficiency, and mitigating noise issues - all within the spatial constraints typical of existing buildings. To address these complexities, software-based integrated planning methods are essential to ensure reliable and efficient system design. In the early project stages, spreadsheet-based tools (e.g., PHPP) are widely used by practitioners for pre-design and proof-of-concept studies. However, the detailed design and techno-economic optimization of HP retrofits require higher temporal resolution and more sophisticated dynamic simulation tools. Therefore, a modular toolbox is proposed to enable a consistent workflow - from pre-design to detailed design and optimization - allowing seamless transition from spreadsheet tools to dynamic simulation environments. The toolbox supports variant management, integrated post-processing, and transparent visualization of energy fluxes and optimization potentials. The methodology is demonstrated through a renovation case study of a multi-apartment building in Vienna, Austria. Several renovation levels and heat pump concepts (heat source, system configuration, and heat emission system) are analyzed and compared in terms of energy and economic performance. The proposed workflow provides a scalable and knowledge-based planning method to support heat pump implementation in multi-apartment building renovations, accelerating the transition towards a renewable and efficient building stock.