scholarly journals Development of scaling prediction tools for solar hot water systems. Part B - Development of an improved calcium carbonate scaling rate model - An experimental and analytical investigation

1999 ◽  
Author(s):  
Derek Baker
Keyword(s):  
Calcium Carbonate ◽  
Analytical Investigation ◽  
Water Systems ◽  
Hot Water ◽  
Rate Model ◽  
Prediction Tools

Identifying and Reducing Scaling Problems in Solar Hot Water Systems

2003 ◽  
Vol 125 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Derek K. Baker ◽  
Gary C. Vliet
Keyword(s):  
Heat Exchanger ◽  
Potable Water ◽  
Hard Water ◽  
Water Systems ◽  
Hot Water ◽  
Tank Wall ◽  
Rate Model ◽  
Premature Failure ◽  
Water Side ◽  
Freeze Damage

In areas with hard water, scaling can reduce the reliability of solar hot water (SHW) systems. Common reliability problems associated with scaling are both mechanical (collector freeze damage, clogged passages, premature failure of pumps and valves) and thermal (efficiency degradation). A mechanistic and a mathematical scaling rate model are presented. Results from controlled experiments investigating the affect of key water chemistry and heat transfer parameters on the scaling rate are summarized. The implications of these results for designing SHW systems for scaling environments are discussed. Most importantly, indirect systems where the potable water side of the heat exchanger is integrated into the storage tank wall, such as in a wrap-around heat exchanger, are shown to be the most mechanically and thermally reliable systems for scaling environments. A new version of the software SolScale is discussed, which is intended to aid in the design of SHW systems to reduce scaling related reliability problems.

Identifying and Reducing Scaling Problems in Solar Hot Water Systems

Solar Energy ◽  
2002 ◽  
Author(s):  
Derek K. Baker ◽  
Gary C. Vliet
Keyword(s):  
Heat Exchanger ◽  
Potable Water ◽  
Hard Water ◽  
Water Systems ◽  
Hot Water ◽  
Tank Wall ◽  
Rate Model ◽  
Premature Failure ◽  
Water Side ◽  
Freeze Damage

In areas with hard water, scaling can reduce the reliability of solar hot water (SHW) systems. Common reliability problems associated with scaling are both mechanical (collector freeze damage, clogged passages, premature failure of pumps and valves) and thermal (efficiency degradation). A mechanistic and a mathematical scaling rate model are presented. Results from controlled experiments investigating the effect of key water chemistry and heat transfer parameters on the scaling rate are summarized. The implications of these results for designing SHW systems for scaling environments are discussed. Most importantly, indirect systems where the potable water side of the heat exchanger is integrated into the storage tank wall, such as in a wrap-around heat exchanger, are shown to be the most mechanically and thermally reliable systems for scaling environments. A new version of the software SolScale is discussed, which is intended to aid in the design of SHW systems to reduce scaling related reliability problems.

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
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