Heat pipe refrigerated shelves

Lead University: Brunel University London

Dr Hussam Jouhara, Prof Savvas Tassou

Collaboration: Flint Engineering Ltd, Sainsburys, APC, Econotherm (UK) Ltd

Summary

The purpose of the work is to test an innovative design of open display cabinet shelves, based on flat heat pipe technology. Their influence on the energy consumption of the cabinet and their effect on enhancing the preservation conditions of food products are analysed. The experimental work is being carried out using two identical commercial open display cabinets; one cabinet equipped with conventional/commercial shelves while the other one equipped with the new actively-cooled flat heat pipe shelves. Both cabinets are placed inside an ISO-certified environmentally controlled test chamber and experiments are carried out under stable environmental conditions of 20°C temperature and 50% humidity (ISO Class 0). Food block simulators and real food products were used for the tests. The temperature distribution in the core of real food products, glass beakers filled with water and food block simulators, as well as the power consumption of the cabinets are measured for the different temperature set points between -1.8°C to 2.0°C. The experimental outcomes so far are that the use of the heat pipe shelves can homogenise the temperature profile of the products, reduce the air temperature variations inside the cabinet’s void and improve the heat transfer between the cabinet, the shelves and the products. Moreover, the heat pipe shelves facilitated the reduction of the electrical energy consumption of the cabinet by 12% approximately, which paves the way to a very reasonable commercial case for the new shelf design. Finally, in order to investigate the possibility of these selves extending the self-life of foodstuffs, a primary analysis examining the acidity levels (pH) of the products was conducted. The experiments showed that almost all products placed on the heat pipe shelves, after 21 days of experiments, had almost the same pH values, even 20 days beyond their expiration date.

Highlights

  • Better temperature distribution across the cabinet
  • Reduction of shelves hot spots
  • Lower running costs of refrigerated display cabinets
  • Possibility of extending the shelf life of food products

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