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Impact of the implementation of a water spraying system on the efficiency of an embedded refrigeration unit.

Incidence de l'implémentation d'un système de pulvérisation de gouttelettes d'eau sur l'efficacité d'un groupe de production de froid embarqué.

Author(s) : VENDE P. E.

Type of monograph: Doctoral thesis

Summary

Spraying the air condenser of a refrigerating unit increases the heat exchange thanks to the evaporation of water in the air or on the wall, which increases the cooling capacity and decreases the compression work. This phenomenon is applied to the automotive context in order to lower the additional fuel consumption induced by the air conditioning when the vehicle is stopped or is at low speed. A self-sufficient, low-energy, space-saving spraying device was thus implemented in order to impact the condenser of the air conditioning system of a vehicle. A sizing study showed that the spraying device should not consume more than 1 kg.h-1 recovered from the condensates on the evaporator. The studied nozzles (hollow cone and flat fan) were therefore chosen according to this criterion. The condenser of the refrigerating unit was isolated in an experimental device to characterize and optimize the water spraying effect. A thermal analysis method of impacted surfaces has been developed to characterize the clogging phenomenon as the heat is exchanged mainly by the surface impact of the exchanger followed by the water film evaporation. For the long term spraying, 17 % clogging area of the exchanger front surface induces 45 % additional pressure drop and around 25 % degradation in the heat transfer. But clogging can be beneficial and store thermal energy when the spraying time does not exceed 25 minutes. Finally, at the end of the study, the spraying device was implemented on the vehicle and first tests showed a real gain brought by spraying, which is encouraging for a possible industrialization of the device.

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Pages: 220 p.

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Details

  • Original title: Incidence de l'implémentation d'un système de pulvérisation de gouttelettes d'eau sur l'efficacité d'un groupe de production de froid embarqué.
  • Record ID : 30032280
  • Languages: French
  • Subject: Technology
  • Publication: Sorbonne Université - Antony - France
  • Publication date: 2018/03/30

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