Optimal fresh-air utilization strategy based on isocost Line: Adaptability analysis for constant temperature and humidity air-conditioning system

Reducing building operational energy consumption is important for achieving carbon peaking and carbon neutrality. The energy consumption of constant temperature and humidity air-conditioning systems is high owing to the need for strict temperature and humidity control. To maintain working efficiency or meet relative pressure differential requirements, a significant amount of fresh air must be introduced. In our previous study, an optimal fresh air utilization strategy for all conditions was developed for cost savings (including energy, CO₂ emissions, and monetary costs) by considering different air-handling process costs. In this paper, the dynamic chiller station performances are considered to exploit the cost-saving potential for the developed strategy, and the cost-saving performance analyses are investigated under different application scenarios including weather, internal load, and system performances by simulation in a constant temperature and humidity air-conditioning system. The test results show that the optimal fresh air utilization strategy can realize cost-effectiveness in all scenarios, and achieve 0.77%–49.03% annual primary energy saving under a wide range of internal load variations. Optimizing the supply air state and selecting the appropriate air-handling process cost value can further unlock energy-saving potential and reduce application costs.