Fouling of plastic fiber heat exchanger

abstract

English

Warm wastewater can be used as a source of heat for heat pumps in buildings such as gyms, swimming pools, and laundries. Unfortunately, heat exchangers installed in a sewage channel are negatively affected by fouling because deposits on the heat exchange surface create additional resistance to heat transfer and decrease the efficiency of the system. Heat exchangers consisting of polypropylene hollow fibres were prepared and tested to transfer heat from wastewater. Two types of wastewater were studied as foulant: from a shower and from laundry. It was found that these devices have high thermal performance (with an overall heat transfer coefficient of up to 2020 W/m2 K) and can transfer significant amounts of heat (up to 6.5 kW) while working in clean conditions. Fouling tests showed that fouling strongly depends on the type of wastewater. The experiment with shower wastewater showed that fouling was low because it was associated with the accumulation of a small amount of solid particles (particulate fouling). No significant decrease of overall heat transfer coefficient was observed during the two-week test in this case. The experiment with laundry wastewater showed that fouling was extensive because it was associated with both particulate fouling and biofouling. The overall heat transfer coefficient decreased by two times (from 1747 W/m2 K to 863 W/m2 K) during the 35-day experiment.

biofouling, heat exchanger, polymeric hollows fibers

ASTROUSKI, I.; RAUDENSKÝ, M.; DOHNAL, M.

23. 8. 2014

978-80-02-02555-9

21st International Congress of Chemical Engineering CHISA 2014 and 17th Conference PRES 2014, 23 - 27 August 2014, Praha, Czech Republic, Czech Society of Chemical Engineering

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