PhD Candidate in: -80°C cooling technology with natural working fluids

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About the job

Through a collaboration agreement between CERN and NorCC (Norwegian Centre for CERN-related Research), this position is one of a number of jointly-funded NTNU-CERN PhD vacancies in the field of the technological sciences (engineering projects). The successful candidate will spend 18 months at NTNU followed by 18 months at CERN, while remaining active in the PhD Programme at both institutions for the full 36 months. For the position of PhD Candidate, the goal is the completion of doctoral education at NTNU and CERN, including an obtained doctoral degree from NTNU.

A jointly-funded NTNU-CERN PhD vacancy is available at the Department of Energy and Process Engineering (EPT) at NTNU within the Refrigeration research group on the topic of " -80°C cooling technology with natural working fluids [short name: cool -80°C]”.

The Refrigeration research group has well-established expertise and networks in the field of vapour compression systems applying natural working fluids for various applications within different industrial sectors. In close cooperation with CERN, the research group is involved in several national and international research projects. The PhD Candidate will be integrated in the research teams at both NTNU and CERN and will benefit from the knowledge of senior researchers during the PhD work, having access to research facilities at both institutions. Workshops will be organized to bring experts in the field together to share and transfer their knowledge, both from outside and inside the two organizations.

Refrigeration technology: The world is facing significant environmental challenges related to conventional refrigerants with globally contribute to more than 2% of the total greenhouse gas emissions. Most of the currently applied synthetic refrigerants will be restricted, due to human health and environmental risks of their decomposition produces (PFAS) in the very near future. The development of sustainable refrigeration technology, applying natural working fluids, will support CERN and NTNU to exploit novel low and warm temperature refrigeration technology. The temperature range below -55 °C is of special interest for future detector cooling at CERN and the preservation of high-quality fish in Norway. Internationally there is also interest for medical applications like vaccine storage and transport at these temperature levels.

Refrigeration systems are required to transfer heat from the various heat sources in the particle detectors from CERN to maintain a safe and reliable temperature level of the valuable equipment during stand still and experimental campaigns. Within the current cooperation project between CERN and the Department of Energy and Process Engineering (EPT), CO2 is applied as the as working fluid to provide cooling for detectors at a temperature level from room temperature down to -50°C. The past developments have proved that for the specific geometry of detector evaporators being long small diameter pipes, an evaporative cooling at high reduced pressures is most beneficial for the overall heat transfer being a combination of heat transfer coefficients and pressure drop and hence temperature losses. Future detector technologies either require cooling temperatures around room temperature or colder than the capability of the current used CO2 cooling in the range of -50°C to -80°C and beyond. For theses cold application new refrigerant candidates must be explored and Krypton (R784) has been identified as a possible working fluid.

The application of these new refrigerants requires novel refrigeration cycles taking into account other specific requirements of the detector like gradual cooldown, small temperature gradients and large heat load differences. As these working fluids are currently not applied in vapour compression cycles, the development and evaluation of compressor and pumps configurations is crucial to prepare the knowledge for the upcoming decisions to step into the next development phase (demo plant installation). At the same time, heat transfer and pressure drop measurements have to be performed to validate models, to enable a proper design of heat exchangers.

Key components of the PhD work include:

• further development of the Critical Region Cooling Technology work with focus on critical components with respect to availability and performance.
• Component design and modelling: Heat exchanger design investigations, compressor & pump/ejector design proposals based on industrial / available oil-free operating devices. [@ NTNU]
• Process analysis and simulation: experimental investigation on heat transfer and pressure drop in relevant heat exchanger geometries. [@ CERN]

Your supervisor will be Professor Armin Hafner at NTNU and Ing. Bart Verlaat at CERN

Duties of the position

• Evaluate the potential of different natural working fluids and processes for the cooling of equipment in the range of -55°C to -80°C domain with respect to radiation hardness, environment, availability, safety, and cost
• Further develop the static and dynamic simulation tool to perform advanced modelling of the sub- and supercritical heat transfer processes with Krypton and hydrocarbon fluids
• Develop a thorough specification for critical components like compressors, pumps and heat exchangers considering the specific requirements of detectors like gradual cooldown, small temperature gradients and large heat load differences
• Describe the synergies when utilizing these technologies within the food processing industry in Norway
• Perform heat transfer and pressure drop measurements with relevant geometries
• Validate the model with initial results from these experimental campaigns at CERN
• Disseminate the findings and results towards the scientific, industrial, and public sector
   

First part of PhD at NTNU (18 months): course work and developing components specification and sourcing

Second part of PhD at CERN (18 months): experimental investigation on heat transfer and pressure drop, model validation

Required selection criteria

• You must have a professionally relevant background in refrigeration engineering.
• Your education must correspond to a five-year Norwegian degree program, where 120 credits are obtained at Master's level.
• You must have a strong academic background from your previous studies and an average grade from the Master's degree programme, or equivalent education, which is equal to B or better compared with NTNU's grading scale. If you do not have letter grades from previous studies, you must have an equally good academic basis. If you have a weaker grade background, you may be assessed if you can document that you are particularly suitable for a PhD education.
• Master's students can apply, but the master's degree must be obtained and documented by 30.09.2024.
• You must meet the requirements for admission to the Faculty's Doctoral programme
• You must have experience in dynamic modelling of energy systems with heat pumps
• You must present a strong interest for the modelling and simulation of complex multi-physical systems including heat- and mass transfer.
• You must have experience with experimental investigations and data analysis
• Good written and oral English language skills.
• You must be a citizen of a CERN Member State or Associate Member State as listed in CERN Member States.

The appointment is to be made in accordance with Regulations on terms of employment for positions such as postdoctoral fellow, Phd candidate, research assistant and specialist candidate and Regulations concerning the degrees of Philosophiae Doctor (PhD) and Philosodophiae Doctor (PhD) in artistic research national guidelines for appointment as PhD, post doctor and research assistant 

Preferred selection criteria

• Scientific publications are an advantage 
• Good written and oral Norwegian language skills

Personal characteristics

• enthusiastic: to encourage other students during supervision of MSc candidates.
• competent: able to communicate with colleagues 
• conscientious: we like if you are a person which prefers to plan ahead
• extrovert: you prefer being sociable, outgoing, and talkative

Emphasis will be placed on personal and interpersonal qualities.

We offer

• exciting and stimulating tasks in a strong international academic environment
• an open and inclusive work environment with dedicated colleagues
• favourable terms in the Norwegian Public Service Pension Fund
• employee benefits

Salary and conditions

General

The PhD candidacy begins with a contract of employment at NTNU for a duration of 18 months, followed by a contract of association and corresponding stipend at CERN for a duration of 18 months. You will remain active in the PhD Programme at both institutions for the full 36 months. Your NTNU supervisor will assist you with your applications to the NTNU and the CERN PhD Programme. A travel allowance is available when travel between NTNU and CERN is deemed appropriate by your supervisors.

Contract of employment at NTNU

During the 18-month period at NTNU, you will have a contract of employment as a PhD candidate (code 1017). PhD Candidates are normally paid NOK 532 200 per annum before tax, depending on qualifications and seniority. From the salary, 2% is deducted as a contribution to the Norwegian Public Service Pension Fund.

Appointment to a PhD position requires that you are admitted to the PhD programme in Engineering within three months of employment, and that you participate in an organized PhD programme during the employment period.

The engagement is to be made in accordance with the regulations in force concerning State Employees and Civil Servants, and the acts relating to Control of the Export of Strategic Goods, Services and Technology. Candidates who by assessment of the application and attachment are seen to conflict with the criteria in the latter law will be prohibited from recruitment to NTNU.

It is a prerequisite you can be present at and accessible to the institution on a daily basis.

Contract of association at CERN:

During the 18-month period at CERN, you will have a contract of association and will be a member of the CERN Doctoral Students Programme, the conditions of which, including details of the monthly stipend, are described in CERN Doctoral Student Programme | SmartRecruiters. You will not be employed by NTNU during this time.

 

About the application

The application and supporting documentation to be used as the basis for the assessment must be in English.

Publications and other scientific work must accompany the application. Please note that your application will be considered based solely on information submitted by the application deadline. You must therefore ensure that your application clearly demonstrates how your skills and experience fulfil the criteria specified above and that all required documentation is included as follows:

• CV and certificates
• Transcripts and diplomas for Bachelor's and Master's degrees. If you have not completed the Master's degree, you must submit a confirmation that the Master's thesis has been submitted
• A copy of the Master's thesis. If you recently have submitted your Master's thesis, you can attach a draft of the thesis. Documentation of a completed Master's degree must be presented before taking up the position.
• Name and contact information of three referees
• Publications or other relevant research work if appropriate

If all, or parts, of your education has been taken abroad, we also ask you to attach documentation of the scope and quality of your entire education, both bachelor's and master's education, in addition to other higher education. Description of the documentation required can be found here. If you already have a statement from NOKUT, please attach this as well

We will take joint work into account. If it is difficult to identify your efforts in the joint work, you must enclose a short description of your participation.

In the evaluation of which candidate is best qualified, emphasis will be placed on education, experience and personal and interpersonal qualities. Motivation, ambitions, and potential will also count in the assessment of the candidates.

NTNU is committed to following evaluation criteria for research quality according to The San Francisco Declaration on Research Assessment - DORA.

General information

Working at NTNU

NTNU believes that inclusion and diversity is our strength. We want to recruit people with different competencies, educational backgrounds, life experiences and perspectives to contribute to solving our social responsibilities within education and research. We will facilitate for our employees’ needs.

NTNU is working actively to increase the number of women employed in scientific positions and has a number of resources to promote equality.

The Department of Energy and Process Engineering (EPT) has established EPT Women in Science. The group is focused on supporting female PhD Candidates, Postdoctoral Fellows, Research Assistants and permanent academic employees within the Department. This support aims to help develop the careers of female PhD Candidates, Postdocs and Research Assistants, and is also made visible to our student body to encourage them to consider an academic path. As part of the EPT Women in Science initiative we are building an international network, inviting prominent female academics within and beyond the field of Engineering to speak at our events.

As an employee at NTNU, you must at all times adhere to the changes that the development in the subject entails and the organizational changes that are adopted.

A public list of applicants with name, age, job title and municipality of residence is prepared after the application deadline. If you want to reserve yourself from entry on the public applicant list, this must be justified. Assessment will be made in accordance with current legislation. You will be notified if the reservation is not accepted.

If you have any questions about the position, please contact Professor Armin Hafner, armin.hafner@ntnu.no (NTNU) and Ing. Bart Verlaat, bart.verlaat@cern.ch (CERN). If you have any questions about the recruitment process, please contact Megan Norris, megan.norris@ntnu.no.

The city of Trondheim has a population of 200,000. It is a modern European city with a rich cultural scene and is known as the innovation capital of Norway. The Norwegian welfare state, including healthcare, schools, kindergartens and overall equality, is among the best of its kind in the world. Professional subsidized day-care for children is easily available, as is children`s education (including international schools). Trondheim has low crime rates and clean air quality and offers the possibility to enjoy nature, culture and family life.

If you think this looks interesting and in line with your qualifications, please submit your application electronically via jobbnorge.no with your CV, diplomas and certificates attached. Applications submitted elsewhere will not be considered. Upon request, you must be able to obtain certified copies of your documentation.  

Application deadline: 14.10.2024