IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration Subtask C Report, Date: 13.01.2009
Figure 5-9: Silver/copper electrodes for cooling tower basin (courtesy of ECONICsystems)
The silver/copper electrodes are also available for integration in the cooling water pipe
system.
In summary it can be said, that the first results are promising to the development of a
suitable disinfection method for small scale wet cooling towers. However, further research on
the disinfection method and tests in real heat rejection applications are necessary to verify
the effectiveness of the disinfection method in long term tests and for different chemical
composition of the cooling water. This shall be carried out in near future.
5.6 Cost comparison
After analysis and description of the two physical water treatments for a hygienic operation
of small wet cooling towers, it is also worth to compare the estimated cost of the proposed
measures. In the table below the investment and operation cost are listed over an operation
period of 15 years.
Table 5-2 Annual cost of hygienic measures for a small cooling tower (30 kW) over a
operation time of 15 years
Investment Operational cost Maintenance &
replacement
Euro Euro/a Euro/a
page 38
Remarks
UV-C disinfection 450 1) to 1000 2) 90 65 Cleaning, lamp
Silver/copper
disinfection
ions
Note 1) : Equipment according to Figure 5-5
Note 2) : Equipment according to Figure 5-6
100 to 300 0,5 27,5 Inspection
The numbers in the Table 5-2 are calculated for a small wet cooling tower with cooling
capacity of 30 kW under the following conditions: