![Sample our Built Environment journals, sign in here to start your access, Latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5926/TOC-Subject-Sample-2021-Built-Environment.jpg"})
ABSTRACT
A novel liquid upper-feeding micro-channel flat loop thermosyphon (LUF-MCFLTS) system was developed, to eliminate the drying phenomenon of the upper surface in the traditional LTS and provide a highly efficient solution for DC cooling and heat recovery. The effects of cooling capacity (cooling water flow rate and temperature), heat load, and filling ratio on the heat transfer performance of the LUF-MCFLTS system are investigated experimentally. The results indicated that with the increase in cooling water flow, the decrease in cooling water temperature, and the increase in heat load, the heat transfer performance of the LUF-MCFLTS system was better. Under a heat load of 500 W, a cooling water flow rate of 600 L/h, and a cooling water temperature of 15°C, the heat recovery efficiency could reach 86.28%. Compared with the MCFTS and MCFLTS systems in literature, the recovery efficiency of the LUF-MCFLTS system could be increased by 31.6% and 2.64%, respectively. In addition, an effective numerical model to predict the heat recovery efficiency of the LUF-MCFLTS system with the experimental data in the 2.07% error band has been established. This work provides a new idea and theoretical basis for the design of DC cooling and heat recovery system.
Nomenclature
| A | = | area (m2) |
| = | specific heat (J/(kg·K)) | |
| = | latent heat (J/kg) | |
| h | = | convective heat transfer coefficient (W/ |
| I | = | current (A) |
| L | = | length (m) |
| m | = | mass flow rate (kg/s) |
| N | = | number |
| Nu | = | Nusselt number |
| Pr | = | Prandtl number |
| = | heat load (W) | |
| P | = | pressure (Pa) |
| Q | = | energy (W) |
| R0 | = | universal gas constant |
| r | = | radius (m) |
| Re | = | Reynolds number |
| R | = | thermal resistance (K/W) |
| T | = | temperature (K) |
| t | = | time (s) |
| U | = | voltage (V) |
| v | = | velocity (m/s) |
| = | deviation value of the dependent variable | |
| w | = | width (m) |
| = | true value of the dependent variable | |
| Greek symbols | = | |
| σ | = | surface tension coefficient (N/m) |
| λ | = | thermal conductivity (W/(m·K)) |
| ρ | = | density (kg/ |
| = | uncertainty | |
| δ | = | thickness (m) |
| ε | = | emissivity [W/( |
| μ | = | dynamic viscosity [kg/(m·s))] |
| η | = | efficiency |
| Subscripts | = | |
| amb | = | ambient |
| c | = | condenser |
| cw | = | condenser wall |
| cl | = | condensed liquid film |
| DC | = | data center |
| e | = | evaporator |
| ew | = | evaporator wall |
| GWP | = | Global warming potential |
| h | = | heat exchanger |
| IT | = | information technology |
| gr | = | groove |
| LUF | = | liquid upper-feeding |
| LTS | = | loop thermosiphon |
| lrl | = | liquid return line |
| l | = | liquid |
| ltl | = | liquid transmission line |
| MCFTS | = | micro channel flat thermosiphon |
| MCFLTS | = | micro-channel flat loop thermosiphon |
| ODP | = | Destroy ozone potential |
| PVC | = | polyvinyl chloride |
| TS | = | thermosyphon |
| tg | = | thermal grease |
| vtl | = | vapor transmission line |
| v | = | vapor |
| vf | = | vapor flow |
| w | = | water |
| wr | = | wick resistance |
Acknowledgements
This work was supported by the Department of Science and Technology of Guangdong Province, China [2019A050509008] and European Commission H2020-MSCA-IF-2018 Programme [835778-LHP-C-H-PLATE-4-D].
Data availability statement
The participants of this study did not give written consent for their data to be shared publicly, so due to the sensitive nature of the research supporting data is not available.
Disclosure statement
No potential conflict of interest was reported by the authors.