Experimental study and analysis of an air-cooled condenser with the fouling on the heat exchange surface for small-scale commercial refrigeration systems

Abstract

The paper presents the results of a theoretical and experimental study aimed at improving the efficiency of commercial refrigeration systems and taking into account the external negative impact on heat transfer and aerodynamics of an air-cooled condenser. The issues of the impact of solid fouling on the outer heat transfer surface of the air-cooled condenser as a factor that worsens its energy efficiency and operational reliability have been studied. A small-scale commercial refrigeration machine has been used for carrying out the study. To create external real conditions in the experimental bench, a climatic chamber and a thermostatic chamber are provided. Three types of solid fouling have been used: dust, fluff, and sand. The fouling has been collected from real operating air-cooled condensers which are identical to the experimental heat exchanger. The experimental study has been carried out with a variable mass of fouling, which made it possible to simulate various real operating conditions for the air-cooled condenser. As a result of the experiment, it has been found that out of a set of fouling roadsides, the dust has the greatest negative impact on the characteristics of the refrigeration machine as a whole, and sand has the greatest negative effect on the internal characteristics of the air-cooled condenser. Recommendations are made to determine the moment of cleaning the surface of the air-cooled condenser based on energy-saving parameters. It is proposed to fix the moment of cleaning using computer software using the permissible air mass velocity as a key parameter and the refrigeration machine operation interval under this condition.