Optimal cycle for plate heat exchanger cleaning in customer substation

Over the time a heating surface of a heat exchanger should be cleaned to remove fouling deposits. If this is not done regularly, the maintenance and operating costs are increased. Therefore, it is important to determine an optimal cycle for heat exchanger cleaning. Objectives of this paper are to assess an impact of deposits on heat exchanger plates, on changing their heating and hydraulic characteristics, on the amount of electric energy required to pump heating mediums through the heat exchanger, on the size of the heating surface and on the frequency of cleaning. In addition to that, a formation of fouling deposits on the heat exchanger in customer substation may lead to an increased heating medium now rate that is required from a district heating system. Developed mathematical model allows to evaluate different factors impacting heat exchanger performance and to determine an optimal period between two consecutive heat exchanger cleanings. The advantages of use of plate-and-frame heat exchangers in district heating system customer substations (for domestic hot water and space heating) as compared to shell-and-tube heat exchangers are also demonstrated.