TRNSYS-Based Analysis of a BIT-Integrated Water-to-Water Heat Pump System for Low-Carbon Residential Heating

Heating accounts for more than 70% of energy use in the Dutch residential sector, highlighting the urgent need for low-carbon alternatives. This study investigates the integration of Building-Integrated Thermal (BIT) collectors with a water-to-water heat pump (WWHP) system as a compact, quiet, and visually integrated heating solution. Compared to conventional air-to-water heat pumps (AWHPs), which can cause noise and visual disruption in dense urban settings, BIT collectors can be embedded into façades or rooftops while harvesting renewable ambient energy. A detailed TRNSYS simulation was performed for a typical multi-family apartment building using a BIT+WWHP configuration. A standard AWHP setup was modeled as a baseline reference. Results show that the BIT+WWHP system achieves higher seasonal performance, reduced auxiliary energy demand, and improved integration with building architecture, confirming its suitability for energy-efficient urban housing.