Problems in design of cooling systems for particle detectors and relevant electronics.

We present the main design approaches for cooling systems of particle detectors and their electronics. The paper summarizes our 25 years-long participation and experience in design and implementations of cooling systems for major detector projects at CERN. We present some typical use cases that differ in cooling power and employ different refrigerants or refrigerant mixtures. The first use case deals with a small, lightweight mobile device using air as cooling medium that is aimed for applications requiring cooling power up to thousand watts or lower and temperatures down to -40°C. The second use case represents evaporative system using fluorocarbon refrigerants (as both a single fluid and mixtures) capable of cooling the electronics down to -30°C. The unusual demand for vapour tubes without thermal insulation resulted in special design measures to keep surfaces of exhaust pipes from evaporator above a dew point. The results achieved in the above use cases will reflect running condition experience on typical installations, now in service for more than 8 years. Notes about mathematical modelling and simulation will indicate a reduction in development and experimental time needed for verification of the final solutions.