Determination of Ice volume by capacitance measurement

(supervisor: Dave Langstaff)

Nature of project: experimental, experimental

Available to full-time physicists or joint students.

Project description and methodology

A design of a novel fridge for medical applications uses the meltwater from a reservoir of ice to maintain a temperature of approximately 4C in the refrigeration chamber. The meltwater is recirculated to the reservoir after passing around the chamber. The manufacturer of the fridge would like to know if it is feasible to use the difference in capacitance between ice and water to determine the proportion of ice remaining in the reservoir. The capacitance would be measured with the aid of suitable electrodes attached to the plastic reservoir and either a hand-held capacitance meter or an integrated circuit module connecting to a USB port on a computer.

A successful project will develop beyond the above in one/some of the following directions:
Developments of this project would go beyond the basic laboratory investigation and take the system towards implementation as an embedded instrument. The instrument should be implemented on an Arduino processor interfaced to a capacitance measuring integrated circuit. The software written to run on the Arduino should be able to assess the water level during the fill phase and subsequently display the percentage of ice remaining in the reservoir.

When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.

This project is only available as a Y3 project.

Initial literature for students:

  1. Capacitive-Based Liquid Level Sensing Sensor Reference Design, Texas Instruments, 2015
  2. Liquid Level Sensing Using Capacitive-to-Digital Converters, Analog Devices, 2015
  3. X. Zhi, H.C. Cho, B. Wang, C.H. Ahn, H.S. Moon, J.S. Go, Development of a capacitive ice sensor to measure ice growth in real time, Sensors (Basel, Switzerland), 15 (2015) 6688-6698.
  4. V.F. Petrenko, Electrical Properties of Ice, COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH, 1993.

Novelty, degree of difficulty and amount of assistance required

The project will require some theoretical calculations on values of capacitance for the electrodes. There will be some assembly of electrodes onto a suitable reservoir container and experimental work in determining capacitance at different liquid levels and ice proportions.

Project milestones and deliverables (including timescale)

milestoneto be completed by
Theorectical calculations and initial electrode designend of October
First measurementsChristmas
detailed measurements of Ice systemend of February
Calibrate systemEaster

Students taking this project will have to submit a full risk assessment form