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Knapp, Samuel
Publications (3 of 3) Show all publications
Knapp, S. & Nordell, B. (2017). Energy-efficient Legionella control that mimics nature and an open-sourcecomputational model to aid system design (ed.). Paper presented at Asian Symposium on Computational Heat Transfer and Fluid Flow (ASCHT), Busean, South Africa, Nov 22-25 2015. Applied Thermal Engineering, 127, 370-377
Open this publication in new window or tab >>Energy-efficient Legionella control that mimics nature and an open-sourcecomputational model to aid system design
2017 (English)In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 127, p. 370-377Article in journal (Refereed) Published
Abstract [en]

The Duck Foot Heat Exchange Model (DFHXM) was developed to aid design of energy efficient thermal pasteurization systems for water but applies to all fluids. Here, the freely available Microsoft Excel model and potential applications are described. The principle imitates countercurrent heat exchange in the feet of ducks which reduces environmental heat losses in cold climates. The designed system pasteurizes the chosen fluid by maintaining a required disinfection temperature for a given time. A heat exchanger preheats incoming fluid before reaching a heating reservoir (electric, solar, gas, etc.). Upon exiting the heater, fluid reenters the same heat exchanger to cool down, simultaneously preheating new incoming fluid. Thus, the design only requires a heater to add the necessary heat not gained in the heat exchanger and to cover environmental heat losses. The DFHXM allows users to input parameters to simulate their specific duck foot (DF) systems and obtain transient and steady-state fluid temperatures within the heat exchanger and heating reservoir. The model has the flexibility to simulate a wide variety of designs, and potential applications to Legionella control and solar-thermal water disinfection are discussed. Reported simulations agreed well with experimental results for transient and steady-state temperatures, the largest discrepancy in steady-state temperatures being 4.6 %.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Water Engineering
Research subject
Water Resources Engineering
Identifiers
urn:nbn:se:ltu:diva-7772 (URN)10.1016/j.applthermaleng.2017.08.006 (DOI)000413608400036 ()2-s2.0-85027507018 (Scopus ID)63139f49-d53b-483d-bf97-5ca92b7637b1 (Local ID)63139f49-d53b-483d-bf97-5ca92b7637b1 (Archive number)63139f49-d53b-483d-bf97-5ca92b7637b1 (OAI)
Conference
Asian Symposium on Computational Heat Transfer and Fluid Flow (ASCHT), Busean, South Africa, Nov 22-25 2015
Note

Konferensartikel i tidskrift

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Amara, S., Baghdadli, T., Knapp, S. & Nordell, B. (2017). Legionella Disinfection by Solar Concentrator System (ed.). Renewable & sustainable energy reviews, 70, 786-792
Open this publication in new window or tab >>Legionella Disinfection by Solar Concentrator System
2017 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 70, p. 786-792Article in journal (Refereed) Published
Abstract [en]

The current study concerns the fundamental problems of Legionnaires disease. Four decades after Legionnaires' bacteria was first identified there is still a low level of clinical awareness. Humans are infected by inhalation of aerosolized water and/or soil contaminated with the bacteria. Several control methods are available for water disinfection: biocide, ultraviolet light sterilization, copper-silver ionization, ozonation etc. but only thermal treatment can completely eliminate Legionella, which is killed almost instantly at 70 °C. The current paper describes Legionella disinfection by a solar concentrator combined with a heat recovery system that reduces the heat demand. Though this study is made for a small system (160 l of hot water per day) the system can be enlarged (more hot water and more solar collector area) and the results are thus valid also for such larger systems. Here experiments of water treatment by a solar concentrator are summarized and analyzed where the temperature exceeds 80 °C at the outlet of the heat exchanger.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Water Engineering
Research subject
Water Resources Engineering
Identifiers
urn:nbn:se:ltu:diva-9715 (URN)10.1016/j.rser.2016.11.259 (DOI)000396184900059 ()2-s2.0-85007574058 (Scopus ID)8621bd47-c8d6-44d2-b6f9-a543ba86d878 (Local ID)8621bd47-c8d6-44d2-b6f9-a543ba86d878 (Archive number)8621bd47-c8d6-44d2-b6f9-a543ba86d878 (OAI)
Note

Validerad; 2017; Nivå 2; 2017-03-08 (rokbeg)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-12-14Bibliographically approved
Knapp, S. (2015). Duck Foot Heat Exchange Model. Paper presented at . Luleå tekniska universitet
Open this publication in new window or tab >>Duck Foot Heat Exchange Model
2015 (English)Other (Other academic)
Abstract [en]

The Duck Foot Heat Exchange Model (DFHXM) simulates the start up and steady-state conditions within a duck foot heat exchange system. The system consists of a heat exchanger and heating reservoir affecting a single flow of fluid. Fluid enters at a defined temperature and passes through a flat-plate, single-pass countercurrent heat exchanger. Fluid re-enters the heat exchanger after passing through a heating reservoir and exits the system near its original temperature. The DFHXM is intended to simulate systems for a variety of pasteurization applications including Legionella eradication and solar water disinfection.

Place, publisher, year, pages
Luleå tekniska universitet, 2015
National Category
Water Engineering
Research subject
Water Resources Engineering
Identifiers
urn:nbn:se:ltu:diva-33888 (URN)10.5281/zenodo.15451 (DOI)e3551bd3-b4a6-40d2-b05e-6aaecbe68fe7 (Local ID)e3551bd3-b4a6-40d2-b05e-6aaecbe68fe7 (Archive number)e3551bd3-b4a6-40d2-b05e-6aaecbe68fe7 (OAI)
Note

Godkänd; 2015; 20150115 (bon)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-02-13Bibliographically approved
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