Chemistry of the Interfaces of an Electric Water Heater: Implications from an Input-Output Analysis

2010 ◽  
Vol 45 (1) ◽  
pp. 99-109
Author(s):  
Martin B. Hocking

Abstract In a case study, this paper responds to increasing public interest in water quality issues by investigating chemical changes as water passes through a domestic water hot water system. Elemental changes were measured by simultaneous analysis of the incoming and outgoing water streams and the deposited sediment from an electric water heater tank. The results may alter some long-held beliefs. The collected and dried sediment from the tank was analyzed for thirty common elements by inductively coupled plasma and atomic absorption techniques. Of the 25 elements found, the dominant seven in order of concentration were magnesium, aluminum, copper, zinc, manganese, iron, and sodium, as well as some surprising traces of other elements. The cold water input and the heated output were also analyzed for thirteen measurable elements. In the heated water output, magnesium had a massive 151% increase in concentration, followed by much more modest increases shown by arsenic, calcium, lead, potassium, silicon, and strontium. None of these mass balance changes compromised the potability of the water. The six elements, aluminum, boron, copper, iron, manganese, and sodium, showed decreases in aqueous concentrations on heating, thereby improving the water quality.

2013 ◽  
Vol 6 (2) ◽  
pp. 99-114 ◽  
Author(s):  
E. J. Pieterse-Quirijns ◽  
E. J. M. Blokker ◽  
E. van der Blom ◽  
J. H. G. Vreeburg

Abstract. Existing Dutch guidelines for the design of the drinking water and hot water system of non-residential buildings are based on outdated assumptions on peak water demand or on unfounded assumptions on hot water demand. They generally overestimate peak demand values required for the design of an efficient and reliable water system. Recently, a procedure was developed based on the end-use model SIMDEUM to derive design-demand-equations for peak demand values of both cold and hot water during various time steps for several types and sizes of non-residential buildings, viz. offices, hotels and nursing homes. In this paper, the design-demand-equations are validated with measurements of cold and hot water patterns on a per second base and with surveys. The good correlation between the simulated water demand patterns and the measured patterns indicates that the basis of the design-demand-equations, the SIMDEUM simulated standardised buildings, is solid. Surveys were held to investigate whether the construction of the standardised buildings based on the dominant variable corresponds with practice. Surveys show that it is difficult to find relationships to equip the standardised buildings with users and appliances. However, the validation proves that with a proper estimation of the number of users and appliances in only the dominant functional room of the standardised buildings, SIMDEUM renders a realistic cold and hot water diurnal demand pattern. Furthermore, the new design-demand-equations based on these standardised buildings give a better prediction of the measured peak values for cold water flow than the existing guidelines. Moreover, the new design-demand-equations can predict hot water use well. In this paper it is illustrated that the new design-demand-equations lead to reliable and improved designs of building installations and water heater capacity, resulting in more hygienic and economical installations.


2013 ◽  
Vol 827 ◽  
pp. 99-104
Author(s):  
Bin Li ◽  
Xi Chen ◽  
Xin Hao Li ◽  
Lu Kuan Ma ◽  
Wen Bo Lu ◽  
...  

Now in general use in solar water heater, there is a long pipeline between water heater and tap, we have to empty the stored cold water before we use the hot water; and usually the water cannot meet required temperature due to the heating delay effect, thus the water also should be emptied, which leads to a waste of water resources. In order to solve this water wastage, we propose a device which can help to control the temperature and backflow of the water in water heater. The device accomplishes backflow of cold water automatically under the effect of gravity, and refluxed water will be stored in the recycle-water tank, thus ensuring the result that the water temperature satisfies the requirement. After the recycle-water tank is full, it will trigger the buoy to control the relay switch, then the water pump start to work to force the water into the water heater tank. Thus, realizing the recycling of water. This device can significantly save water resources in domestic water, and it has a broad market prospect.


2012 ◽  
Vol 5 (1) ◽  
pp. 455-471
Author(s):  
E. J. Pieterse-Quirijns ◽  
E. J. M. Blokker ◽  
E. van der Blom ◽  
J. H. G. Vreeburg

Abstract. Existing guidelines related to the water demand of non-residential buildings are outdated and do not cover hot water demand for the appropriate selection of hot water devices. Moreover, they generally overestimate peak demand values required for the design of an efficient and reliable water system. Recently, a procedure was developed based on the end-use model SIMDEUM® to derive design rules for peak demand values of both cold and hot water during various time steps for several types and sizes of non-residential buildings, i.e. offices, hotels and nursing homes. In this paper, the design rules are validated with measurements of cold and hot water patterns on a per second base. The good correlation between the simulated patterns and the measured patterns indicates that the basis of the design rules, the SIMDEUM simulated standardised buildings, is solid. Moreover, the SIMDEUM based rules give a better prediction of the measured peak values for cold water flow than the existing guidelines. Furthermore, the new design rules can predict hot water use well. In this paper it is illustrated that the new design rules lead to reliable and improved designs of building installations and water heater capacity, resulting in more hygienic and economical installations.


2005 ◽  
Vol 2 (4) ◽  
pp. 284-289 ◽  
Author(s):  
M. H. Saidi ◽  
A. Abbassi ◽  
M. A. Ehyaei

In this paper, a 5kW PEM fuel cell including burner, steam reformer, and water heater for domestic application has been considered. Water is used for cooling of the fuel cell. Cold water is passed through a cooling channel, warmed up and used for domestic water heating. To increase the efficiency, outlet steam of fuel cell is fed to the reformer. The perfomance of the system is optimized by exergy analysis based on the second law of thermodynamics. Also, the effect of burner, fuel cell temperature and stoichiometric air fuel ratio are investigated. In this analysis, pressure loss in the fuel cell and heat transfer of the cooling channel are taken into account whereas, pressure loss in burner and reformer are neglected. Results show, to minimize the entropy generation, fuel cell temperature must be increased to maximize PEM fuel cell temperature. Also, burner and reformer temperature and stoichiometric air fuel ratio must be decreased to 900K, and λ=2, respectively.


1997 ◽  
Vol 43 (12) ◽  
pp. 1189-1196 ◽  
Author(s):  
Carmen Moreno ◽  
Isabel de Blas ◽  
Francisca Miralles ◽  
David Apraiz ◽  
Vicente Catalan

In this paper we describe a simple method, noncorrosive to pipes, for the eradication of Legionella pneumophila from potable water systems. This method is based on the systematic purging of the pipe networks with cold water containing 1 – 1.5 mg residual chlorine/L. In the hot water system, a new pipe bypassing the water heater was installed, whereas in the air conditioning system, the circuit is purged with water from the tap water system. The feasibility of this method was studied in two hotels in which the presence of Legionella was detected despite treatment of the water by the hyperchlorination method. The evolution of the presence of Legionella was studied by culture and polymerase chain reaction. Eighty samples from hotel A and sixty-seven samples from hotel B were analyzed during the time that the eradication method was applied. Our results showed that this method permitted the effective elimination of L. pneumophila after 5 months in hotel A and 7 months in hotel B.Key words: Legionella pneumophila, eradication.


Author(s):  
Bhagavathami Meenaksh ◽  
Chitraa R. Chandran ◽  
Aravindhan Thathchari Ranganathan ◽  
Kavindapadi Venkateswaran Rama ◽  
Valarmathy Srinivasan

Background: This study aims to determine and compare the levels of trace elements copper, zinc, selenium and chromium in GCF and serum of patients with periodontitis and healthy individuals. Methods: This cross sectional study includes 24 study subjects recruited from the patients reporting to the Department of Periodontics , Tagore Dental College Chennai. All the selected patients were subjected to a clinical examination done by a single examiner. The estimation of trace elements Copper, Zinc, Selenium and Chromium in GCF and serum is performed using Perkin Elmer optima 5300 Inductively Coupled Plasma Emission Spectrometer (ICPOES). Results: GCF and serum copper levels showed no significant difference in both periodontitis and healthy groups . Selenium levels tend to be the same in both groups. Serum zinc levels are more in periodontitis patients than healthy subjects (p less than 0.01). GCF chromium levels are found to be more in patients with periodontitis than healthy. Conclusions : More research is therefore needed to monitor the role of these trace elements C with an increased sample size to ascertain whether they are associated with a reduced risk of periodontitis.


2014 ◽  
Vol 587-589 ◽  
pp. 243-246
Author(s):  
Chu Ping Lu ◽  
Kai Ji

This paper is as an example of the hot water supply of the hotel in the city,The design of the hot water system is the solar energy and the air source heat pump,includes:the selection calculation of the air source heat pump of the water heater , the selection and calculation of the solar collector,the determination of the thermal storage tank and the determination of the circulating water pump of heat collecting .


1988 ◽  
Vol 5 (4) ◽  
pp. 423-431
Author(s):  
H.P. Garg ◽  
N.K. Bansal ◽  
D.S. Hrishikesan

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