Energy and carbon performance analysis of an operating room air conditioning system integrated with an exhaust air source heat pump using EnergyPlus : The case of A

Abstract

Operating room air conditioning systems supplying 100% outdoor air generate high energy loads, particularly in hot and humid climates like Antalya. This study evaluates a minimal‐intervention retrofit to improve the energy efficiency of an operating room HVAC system through year‐round recovery of residual exhaust‐air energy downstream of the existing run‐around coil (RAC). Using EnergyPlus 24.1.0, an 8760‐h single‐zone simulation with TMY3 weather data for Antalya compared the reference system with a scenario integrating an auxiliary exhaust‐air‐source air‐to‐water heat pump under identical geometry, ventilation, and operating schedules. This heat pump utilizes exhaust air, after the existing run‐around coil, to provide hydronic pre‐heating or pre‐cooling to the fresh air line without direct refrigerant contact. The annual simulations predicted a 24.75% reduction in total site energy consumption, dropping from 149.66 GJ/year in the reference scenario to 112.62 GJ/year. Specifically, electricity usage decreased from 121.23 to 96.69 GJ/year, and natural gas from 28.43 to 15.93 GJ/year. Heating‐ and cooling‐related energy use decreased by 27.11% and 66.85%, respectively. Consequently, the annual carbon footprint was reduced by 3.90 tCO ₂ e/year (from 17.39 to 13.49 tCO ₂ e/year), corresponding to a 22.42% reduction. The results indicate that the proposed configuration can achieve substantial reductions in annual energy consumption and operational carbon emissions while maintaining complete separation between the supply and exhaust air streams, supporting its application as a minimal‐intervention retrofit option for existing operating‐room HVAC systems.