Refroidissement d'une armoire de Télécommunication avec Bouche Diphasique Thermosyphon

摘要

France Telecom owns telecommunication cabinets whose power is limited because of the heat dissipation of active devices which leads to increased internal temperature. Power equipment limits the number of clients that can connect to networks services with high data rates. In addition to this constraint, the cabinets are subject to climate-related impacts (sunlight) that can be severe and difficult to master. This requires the integration of cooling systems to maintain the temperature of components below the limit (55 ° C). It is with this aim that this work was conducted in the laboratory Femto-ST in collaboration with the R & D department of France Telecom in Lannion.Cooling the phase change is promoted to maintain the operating temperature of the stable and system for use in systems with high power density. The loops are two-phase cooling systems for thermal control and operate passively without mechanical pumping of the coolant.After a literature review on two-phase cooling loops and their applications, it was found that the thermosyphon loops are particularly suitable for applications where low cost, energy efficiency and reliability maintenance are desired. This study was conducted by following a set of specifications proposed by France Telecom which involves: (i) develop a numerical model to model transfers exchanged between the cabinet and the telecommunications environment, (ii) conduct an experimental study to design a thermosyphon loop for cooling telecommunication cabinets.The memory of this thesis shows the limitation of conventional cooling systems using air flow forced convection or other fluids without phase change. A numerical model is developed to enable the prediction of temperatures at the inlet of heated enclosures for different climatic conditions. The choice is focused on the use of a nodal network modeling. The modeling is done by three-dimensional and transient. We also modeled the solar radiation, which applies to the telecommunications closet. The developed model was validated by comparison between the results of modeling and those obtained from experiments in the laboratory and platform CLIMA at France Telecom. The tests are performed by imposing transient electrical power and varying the temperature or heat flux density solar. All the results obtained allowed to establish a database.The second goal as part of this thesis is the design of a cooling system as a thermosyphon loop. The main constraint has guided this design was that the loop needs to cool the cabinet and provide air temperature at the inlet of the equipment below the limit imposed by the ETSI. This led us to design a prototype of thermosyphon loop with a heat output that must be dissipated is imposed. We showed that this prototype is used to dissipate the heat ratings up to 470 W using a small load of npentane.We conducted tests on the prototype cooling telecommunication cabinet using slightly modified thermosyphon loop. We show that the thermal performance obtained by using a cooling mode loop thermosyphon are better. Thermosyphon loops seem interesting for passive cooling of equipment deployed in a telecommunications network. Indeed, being able to use an air conditioning system independent and requires no energy should be promoted in a reduction of overall energy consumption.