74. Legionella Investigations in Cooling Towers and Hot Water Systems

1999 ◽  
Author(s):  
A. Chamorro ◽  
J. Liu
Keyword(s):  
Water Systems ◽  
Hot Water ◽  
Cooling Towers

Paper 6: Some Basic Considerations in the Practice of Heating, Ventilating and Air-Conditioning

1967 ◽  
Vol 182 (5) ◽  
pp. 129-137
Author(s):  
W. H. Eccleston
Keyword(s):  
Air Conditioning ◽  
Response Rate ◽  
Water Systems ◽  
Thermal Capacity ◽  
Hot Water ◽  
Space Heating ◽  
Noise Attenuation ◽  
Cooling Towers ◽  
Steam Generation ◽  
Fuel Savings

This paper covers some of the basic considerations associated with the practice of heating, ventilating and air-conditioning in temperate climates. A diagrammatic representation of heat loss and gain for a room appears to provide a key to more accurate forecasting of fuel consumption for whole buildings. Further, the smaller the thermal capacity of the system and, therefore, the quicker the response rate, the larger is the possible scope for fuel savings. As far as space heating is concerned water systems are classified and there is reference to the more commonly used heat emitters and some of their characteristics. There is some reference to boiler power both for hot-water heating and steam generation. Ventilation is discussed in the context of terminal points; there is also a brief reference to noise attenuation in ducts and to balancing of systems. Air-conditioning is defined and the better known distribution methods are classified. Packaged water chillers are briefly examined and there are some suggestions regarding ‘mixing-units’. In addition there are some comments on cooling towers. In conclusion there is a plea for standardization and in this particular instance reference is made to specifications for mechanical services works.

Chemical disinfection of Legionella in hot water systems biofilm: a pilot-scale 1 study

2011 ◽  
Vol 64 (3) ◽  
pp. 708-714 ◽  
Author(s):  
Maha Farhat ◽  
Marie-Cécile Trouilhé ◽  
Christophe Forêt ◽  
Wolfgang Hater ◽  
Marina Moletta-Denat ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Contact Time ◽  
Pilot Scale ◽  
Water Systems ◽  
Hot Water ◽  
The Other ◽  
Cooling Towers ◽  
Test Loop ◽  
Growing Conditions ◽  
Chemical Disinfection

Legionella bacteria encounter optimum growing conditions in hot water systems and cooling towers. A pilot-scale 1 unit was built in order to study the biofilm disinfection. It consisted of two identical loops, one used as a control and the other as a ‘Test Loop’. A combination of a bio-detergent and a biocide (hydrogen peroxide + peracetic acid) was applied in the Test Loop three times under the same conditions at 100 and 1,000 mg/L with a contact time of 24 and 3–6 hours, respectively. Each treatment test was preceded by a three week period of biofilm re-colonization. Initial concentrations of culturable Legionella into biofilm were close to 103 CFU/cm2. Results showed that culturable Legionella spp. in biofilm were no longer detectable three days following each treatment. Nevertheless, initial Legionella spp. concentrations were recovered 7 days after the treatments (in two cases). Before the tests, Legionella spp. and L. pneumophila PCR counts were both about 104 GU/cm2 in biofilm and they both decreased by 1 to 2 log units 72 hours after each treatment. The three tests had a good but transient efficiency on Legionella disinfection in biofilm.

Legionnaire’s disease and COVID-19: Could Legionella be acting in conjunction with the Corona virus to aggravate the COVID-19 disease?

2020 ◽  
Author(s):  
Andrew John PENDERY
Keyword(s):  
Drinking Water ◽  
Air Conditioning ◽  
Water Systems ◽  
Contaminated Water ◽  
Cooling Towers ◽  
Age Group ◽  
Corona Virus ◽  
The Usa ◽  
Legionnaire's Disease ◽  
Legionnaire’S Disease

There are some striking similarities between Legionnaire’s disease and COVID-19. Thesymptoms, age group and sex at risk are identical. The geographical distribution of both diseases is similar in Europe overall, and within the USA, France and Italy. The environmental distributions are also similar. However Legionnaire’s disease is caused by Legionella bacteria while COVID-19 is caused by the Corona virus. Whereas COVID-19 is contagious, Legionnaire’s disease is environmental. Legionella bacteria are commonly found in drinking water systems and near air conditioning cooling towers. Legionnaire’sdisease is caught by inhaling contaminated water droplets. The Legionella bacteria does not spread person to person and only causes disease if it enters the lungs.Could the Corona virus be making it easier for Legionella bacteria to enter the lungs?

A Design Method for Thermosyphon Solar Domestic Hot Water Systems

1987 ◽  
Vol 109 (2) ◽  
pp. 150-155 ◽  
Author(s):  
M. P. Malkin ◽  
S. A. Klein ◽  
J. A. Duffie ◽  
A. B. Copsey
Keyword(s):  
Flow Rate ◽  
Design Method ◽  
Water Systems ◽  
Hot Water ◽  
Average Flow Rate ◽  
Domestic Hot Water ◽  
Average Flow ◽  
Solar Fraction ◽  
Wide Range ◽  
Flow Circuit

A modification to the f-Chart method has been developed to predict monthly and annual performance of thermosyphon solar domestic hot water systems. Stratification in the storage tank is accounted for through use of a modified collector loss coefficient. The varying flow rate throughout the day and year in a thermosyphon system is accounted for through use of a fixed monthly “equivalent average” flow rate. The “equivalent average” flow rate is that which balances the thermosyphon buoyancy driving force with the frictional losses in the flow circuit on a monthly average basis. Comparison between the annual solar fraction predited by the modified design method and TRNSYS simulations for a wide range of thermosyphon systems shows an RMS error of 2.6 percent.

Long term durability of crosslinked polyethylene tubing used in chlorinated hot water systems

1999 ◽  
Vol 28 (6) ◽  
pp. 309-313 ◽  
Author(s):  
T.S. Gill ◽  
R.J. Knapp ◽  
S.W. Bradley ◽  
W.L. Bradley
Keyword(s):  
Water Systems ◽  
Hot Water ◽  
Polyethylene Tubing

scholarly journals On Synthesis and Optimization of Cooling Water Systems with Multiple Cooling Towers

2011 ◽  
Vol 50 (7) ◽  
pp. 3775-3787 ◽  
Author(s):  
Khunedi Vincent Gololo ◽  
Thokozani Majozi
Keyword(s):  
Cooling Water ◽  
Water Systems ◽  
Cooling Towers
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