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Sizing of a Domestic Hot Water Heating and Storage System for Short Operating Cycles - A Theoretical Approach

Carlos Pinho(1*)

(1) Mechanical Engineering Department, Faculty of Engineering, University of Oporto, Portugal
(*) Corresponding author


DOI: https://doi.org/10.15866/ireme.v9i4.6671

Abstract


A methodology for the sizing of domestic hot water heating and storage systems is defined, by assuming an extreme operating condition cycle composed of only two parts, a water consumption period and a system repositioning period. In both parts to respond to the extreme hot water demanding conditions, the heating is always on. The subsequent exergy analysis of this domestic hot water production system compares the irreversibility and the exergy efficiency of the water storage and the tankless situation. To carry out such analysis, some basic assumptions were made: a constant temperature heat source, a short duration operating cycle and a constant thermal energy supply. Under these circumstances it is shown that the hot water storage system leads to lower exergy losses while the tankless system is more exergy efficient, but requiring a higher instantaneous thermal power input. The use of the joule effect electricity, as the system heat source, be it a water storage one or a tankless one, maximizes the system irreversibility losses and minimizes the system exergy efficiency. The tankless system, with the joule effect electricity heat source is the worst situation.
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Keywords


Domestic Hot Water; Energy; Exergy; Tankless System

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References


J. Fernández-Seara, F. J. Uhía, J. Sieres, Experimental analysis of a domestic electric hot water storage tank. Part I: Static mode of operation, Applied Thermal Engineering, Vol. 27, n. 1, pp. 129-136, 2007.
http://dx.doi.org/10.1016/j.applthermaleng.2006.05.006

J. Fernández-Seara, F. J. Uhía, J. Sieres, Experimental analysis of a domestic electric hot water storage tank. Part II: Dynamic mode of operation, Applied Thermal Engineering, Vol. 27, n. 1, pp. 137-144, 2007.
http://dx.doi.org/10.1016/j.applthermaleng.2006.05.004

P. González-Altozano, M. Gasque, F. Ibáñez, R. P. Gutiérrez-Colomer, New methodology for the characterization of termal performance in a hot water storage tank during charging, Applied Thermal Engineering, Vol. 84, pp. 196-205, 2015.
http://dx.doi.org/10.1016/j.applthermaleng.2015.03.048

C. Solé, M. Medrano, A. Castell, M. Nogués, H. Mehling, L. F. Cabeza, Energetic and exergetic analysis of a domestic water tank with phase change material, International Journal of Energy Research, Vol. 32, n. 3, pp. 204-214, 2008
http://dx.doi.org/10.1002/er.1341

F. Dammel, J. Winterling, K.-J. Langeheinecke, P., Stephan, Exergy Analysis of a Water Heat Storage Tank, Proceedings of the 2012 COMSOL Conference, Milan, Italy. 2012.

I. Dincer, M., Rosen, Thermal Energy Storage Systems and Applications (John Wiley and Sons, Chichester, UK, 2011).

P. Armstrong, D. Ager, I. Thompson M. McCulloch, Domestic hot water storage: Balancing thermal and sanitary performance, Energy Policy, Vol. 68, pp. 334-339, 2014.
http://dx.doi.org/10.1016/j.enpol.2014.01.012

P. M. Armstrong, M. Uapipatanakul, I. Thompson, D. Ager, M. McCulloch, Thermal and sanitary performance of domestic hot water cylinders: Conflicting requirements, Applied Energy, Vol. 131, pp. 171-179, 2014.
http://dx.doi.org/10.1016/j.apenergy.2014.06.021

B. Wienke, Computing the partial volume of pressure vessels, International Journal of Refrigeration, Vol. 33, n. 4, pp. 868 – 876, 2010.
http://dx.doi.org/10.1016/j.ijrefrig.2009.11.009

L. Borel, Thermodynamique et Énergétique, (1st edition Presses Polytechniques Romandes, Lausanne, Switzerland, 1986).

P. J. Boait, D. Dixon, D. Fan, A. Stafford, Production efficiency of hot water for domestic use, Energy and Buildings, Vol. 54, pp. 160-168, 2012.
http://dx.doi.org/10.1016/j.enbuild.2012.07.011


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