# Experimental Study of a Novel Prototype of Dual-Cycle Two-Phase Cooling System for a Data Cabinet  
[PERSON] School of Aeronautical Science and Engineering, Beihang University, Beijing 100191, China 1,* 1  
consumption, with most data centers still relying on conventional air conditioning cooling [5; 6; 7]. This method has high energy consumption and local hot spots and is becoming increasingly inadequate for high-power density data centers. The power density of data centers is expected to grow from the current 5-10 kW to 20-30 kW per rack [8; 9], with the maximum power density per rack expected to reach 50 kW by 2025. Additionally, the thermal design power of chips has reached 700 W, with Nvidia DGX B200 reaching up to 1000 W, further exacerbating the cooling challenges [10]. Data center cooling methods can be broadly categorized into air cooling and liquid cooling. Air cooling, the most common method, uses air as a medium for heat exchange. It can be further divided into room-level, row-level, and rack-level cooling based on the terminal cooling method [7; 11]. Computer room air conditioning (CRAC) is the most common room-level cooling system, using multi-stage heat exchange, leading to high energy consumption due to the mixing of cold and hot air [12]. Row-level cooling isolates hot and cold channels to avoid mixing but still cannot eliminate local hot spot. Rack-level cooling confines the cooling unit within the cabinet, preventing cold and hot air mixing and reducing the power required for computer room air handling fans, thereby achieving higher heat dissipation efficiency compared to room-level and row-level cooling systems [13]. The optimization of heat dissipation systems in air-cooled data centers focuses on utilizing natural cold sources and improving system performance. Free cooling technologies, such as the two-phase natural loop (TPNL) and two-phase pump-driven loop (TPPL), are commonly used to save energy when outdoor temperatures are low [14; 15]. [PERSON] et al. [16; 17] found through experimental analysis that pumps improve performance by eliminating subcooling and superheating rather than enhancing thermal convection; when the flow resistance is high, the pumps even degrade in performance due to the large pressure drop. [PERSON] et al. [14; 18] studied the heat pipe components in detail by experiment and simulation, obtained the flow distribution under different working conditions, and carried out qualitative analysis of the ideal working conditions. [PERSON] et al. [19] and [PERSON] et al. [20] developed a cooling system with a rotary supercharger and compressor that saves up to 40% of the annual energy compared to CRAC systems. [PERSON] et al. [21] proposed an integrated system combining vapor compression and pump-driven two-phase loop for energy-efficient cooling in data centers. The system operates in the two modes of pump-driven and vapor compression mode. When outdoor temperatures are low, the system is powered by a fluorinated pump, demonstrating exceptional energy-saving performance. The integrated system achieves a maximum energy efficiency ratio (EER) of up to 29.71 [21]. [PERSON] et al. [22] integrated the liquid pump and magnetic suspension compressor into a system, which can achieve efficient operation throughout the year, and the annual coefficient of performance of the system is above 6.5 in most climate zones. There has been extensive research on systems that combine liquid pumps and compressors, which demonstrated superior system performance. Liquid cooling is a more effective method than traditional air cooling for removing heat from servers and equipment. There are three main types of liquid cooling: spray cooling, immersion cooling, and cold plate cooling [23]. Spray cooling involves spraying a liquid coolant onto the surface of a heat source to absorb and remove heat. This method is used for high-power LEDs, electric vehicle battery module cooling, and high-power chips and servers.