Sustainable Thermal Management in Building HVAC

Buildings account for a major share of global energy use, making the adoption of sustainable thermal management technologies essential for reducing carbon emissions.However, existing reviews typically focus on single technologies and do not provide an integrated understanding of how geothermal-solar hybrid heat pumps, variable refrigerant flow (VRF) systems, and thermally driven chillers perform when deployed in practice.This systematic review fills this gap by synthesizing experimental, simulation-based, and optimization studies published between 2010 and 2024 to evaluate the real-world viability, performance, and challenges of hybrid heating, ventilation, and air conditioning (HVAC) systems.Using PRISMA-guided selection and comparative analysis, the review examines 50 peer-reviewed studies covering diverse climates, system configurations, and control strategies.Results show that hybrid geothermal-solar systems and advanced VRF configurations can reduce building energy consumption by up to 40% and significantly lower greenhouse gas emissions, with reported payback periods ranging from 2 to 11 years depending on system complexity and local conditions.Advanced control methods-such as model predictive control and fuzzy logic-consistently enhance efficiency and operational reliability but introduce integration and cost challenges.Practical barriers, including high upfront investment, ground thermal imbalance, and interoperability limitations, remain critical obstacles to large-scale deployment.This review's novelty lies in its integrated assessment across technological, economic, environmental, and control dimensions, providing a unified framework for evaluating hybrid HVAC solutions.The findings highlight actionable pathways for optimizing system design, improving control intelligence, and guiding policy measures that support scalable, cost-effective, and lowcarbon thermal management in buildings.