ORGANISATION/COMPANYUniversité Gustave Eiffel
RESEARCH FIELDEngineering › Civil engineeringEngineering › Mechanical engineeringEngineering › Thermal engineering
RESEARCHER PROFILEFirst Stage Researcher (R1)
APPLICATION DEADLINE21/03/2022 17:00 - Europe/Brussels
LOCATIONFrance › Nantes
TYPE OF CONTRACTTemporary
HOURS PER WEEK35
OFFER STARTING DATE03/10/2022
EU RESEARCH FRAMEWORK PROGRAMMEH2020 / Marie Skłodowska-Curie Actions COFUND
MARIE CURIE GRANT AGREEMENT NUMBER101034248
In the era of big data, it is time to deploy datacenters suitable for intensive processing and storage of digital data. The acceleration currently brought about by the development of IoT (Internet of Things) contributes to the continued growth of new datacenters around the world. It has recently been estimated that this infrastructure represents a non-negligible part of world electricity consumption, going from 2% in 2013 to 13% by 2030.
Added to its major energy cost, it is urgent to understand its functional and social role by taking into account collateral effects as UHI (Urban Heat Islands) before the building of such infrastructures of several hundred square meters on a given territory.
In order to guide the operators of datacenters, the American company of engineers in heating, refrigeration and air conditioning, created thermal directives to ensure the stability of these servers which operate on a daily basis. To dissipate the heat generated by the servers, and to prevent them from overheating, HVAC (Heating, ventilation and air-conditioning) is required in datacenters, the cooling system often represents 50% of the power consumption of a datacenter.
To avoid the systematic use of air conditioning systems, free-cooling is used in temperate climate. It consists of using outdoor air with a temperature lower than the temperature of the indoor environment of the datacenter. In that context, we have recently proposed the design of a cooling storage system based on clay materials in order to reduce the energy consumed due to datacenter cooling (Bouchenna et al. 2021). Our Thermal Energy Storage (TES) system is to be placed upstream of the CRAC (Computer Room Air Conditioner) unit. A direct contact heat exchanger is thereby built as a vertical packed bed, composed of earthen spheres whose imposed heating/cooling cycles comply with ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards. Natural unfired earth material in the sector of building and construction is recognized for its high thermal inertia and low carbon footprint.
Moreover, such hygroscopic clays materials can contribute significantly to the hygrothermal indoor regulation because to their vapor permeability. In such context, earthen wall act as one heat/mass exchanger between the indoor and the outdoor environment, which could reduce the UHI effects. Results show that the pore Reynolds number and sphere diameter exert significant effects on the energy buffering capacity.
A simple relationship has been proposed to link the mass-specific power of the energy storage system, the internal heat exchanger architecture and the pore Reynolds number for purposes of designing raw earth bricks at an elevated scale.
The two next main research directions in the frame of the present PhD proposal are aimed to set of experiments and numerical simulation in order to the characterize:
- the thermal hysteresis behavior with respect to both the material properties and process parameters;
- the role of microporosity in TES performance at upper-scale.
One of the main objectives of the PhD work will be to conduct numerical simulations at pore- and wall-scales, which will be compared to experiments performed in environmental controlled conditions. The scientific program will follow the four mains stages :
1. The state of art related to the characterization of the heat and mass transfer through earthen materials will be performed.
2. A home-built code based on Finite Volume Method is developing from the French side. The student will bring its computation skills to implement the mass transfer model to capture the moisture buffering kinetics.
3. Validation of the model will be performed from experiments at the wall-scale to measure the heat and mass transfer fluxes using coupled remote sensing techniques (i.e. Infra-Red Thermography and Ultrasonic Pulsed Doppler Anemometry). An inverse method will be employed to adjust the real external convective transfer coefficients to the simulations results.
4. The student will produce scientific articles in peer-reviewed journals
The student will be inserted in the GPEM Laboratory constituted of six researchers and 5 technicians working on circular economy and sustainable development. The team has a long experience of interdisciplinary and international collaborative works (Brazil, UK, Spain, Taiwan, China).
- High-quality doctoral training rewarded by a PhD degree, delivered by Université Gustave Eiffel
- Access to cutting-edge infrastructures for research & innovation.
- Appointment for a period of 36 months based on a salary of 2 700 € (gross salary per month).
- Job contract under the French labour legislation in force, respecting health and safety, and social security: 35 hours per week contract, 25 days of annual leave per year.
- International mobility will be mandatory
- An international environment supported by the adherence to the European Charter & Code.
- Access to dedicated CLEAR-Doc trainings with a strong interdisciplinary focus, together with a Career development Plan.
- At the time of the deadline, applicants must be in possession or finalizing their Master’s degree or equivalent/postgraduate degree. At the time of recruitment, applicants must be in possession of their Master’s degree or equivalent/postgraduate degree which would formally entitle to embark on a doctorate.
At the time of the deadline, applicants must be in the first four years (full-time equivalent research experience) of their research career (career breaks excluded) and not yet been awarded a doctoral degree. Career breaks refer to periods of time where the candidate was not active in research, regardless of his/her employment status (sick leave, maternity leave etc). Short stays such as holidays and/or compulsory national service are not taken into account.
At the time of the deadline, applicants must not have resided or carried out their main activity (work, studies, etc.) in France for more than 12 months in the 3 years immediately prior to the call deadline.
Applicants must be available to start the programme on schedule (around 1st October 2022).
- Please refer to the Guide for Applicants available on the CLEAR-Doc website.
- The First step before applying is contacting the PhD supervisor. You will not be able to apply without an acceptation letter from the PhD supervisor.
- Please contact the PhD supervisor for any additional detail on job offer.
- There are no restrictions concerning the age, gender or nationality of the candidates. Applicants with career breaks or variations in the chronological sequence of their career, with mobility experience or with interdisciplinary background or private sector experience are welcome to apply.
- Support service is available during every step of the application process by email: firstname.lastname@example.org
Web site for additional job details
REQUIRED EDUCATION LEVELEngineering: Master Degree or equivalent
REQUIRED LANGUAGESENGLISH: ExcellentFRENCH: Good
- At the time of the deadline, applicants must be in possession or finalizing their Master’s degree or equivalent/postgraduate degree.
- At the time of recruitment, applicants must be in possession of their Master’s degree or equivalent/postgraduate degree which would formally entitle to embark on a doctorate.
International mobility: to be discussed with the PhD thesis supervisor.
EURAXESS offer ID: 716461
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