Fouling of in-sewer heat exchangers: to oversize them or to clean them?

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21110%2F15%3A00241183" target="_blank" >RIV/68407700:21110/15:00241183 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Fouling of in-sewer heat exchangers: to oversize them or to clean them?

Popis výsledku v původním jazyce

In-sewer heat exchangers are subject to fouling reducing heat transfer efficiency. Biofilm growth and renewal after mechanical cleaning as well as probability of biofilm scouring by storm events were studied by combination of biofilm sampling and shear stress modelling. The amount of biofilm decreases with increasing shear untouched tress in the sewer. In sewers with high shear stress (25-32 N/m2) cleaning has no effect as biofilm renewal occurs in less than 2 weeks. In sewers with lower shear stress (4-6 N/m2), cleaning 1 per 2 weeks reduces the amount of biofilm and sediments to about a half. Self-cleansing of heat exchangers during storm events can substitute the cleaning only in summer and in a very limited number of sewers. Cost analysis showed that the smaller the heat exchanger area, the better the strategy to oversize it than to clean it. The necessary oversizing can be derived for a given heat exchanger type and cleaning costs.

Název v anglickém jazyce

Fouling of in-sewer heat exchangers: to oversize them or to clean them?

Popis výsledku anglicky

In-sewer heat exchangers are subject to fouling reducing heat transfer efficiency. Biofilm growth and renewal after mechanical cleaning as well as probability of biofilm scouring by storm events were studied by combination of biofilm sampling and shear stress modelling. The amount of biofilm decreases with increasing shear untouched tress in the sewer. In sewers with high shear stress (25-32 N/m2) cleaning has no effect as biofilm renewal occurs in less than 2 weeks. In sewers with lower shear stress (4-6 N/m2), cleaning 1 per 2 weeks reduces the amount of biofilm and sediments to about a half. Self-cleansing of heat exchangers during storm events can substitute the cleaning only in summer and in a very limited number of sewers. Cost analysis showed that the smaller the heat exchanger area, the better the strategy to oversize it than to clean it. The necessary oversizing can be derived for a given heat exchanger type and cleaning costs.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10511 - Environmental sciences (social aspects to be 5.7)

Projekt

<a href="/cs/project/TA03020600" target="_blank" >TA03020600: Získávání tepelné energie z odpadní vody v kanalizačních sítích (enKAN)</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2015

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů