Environmental Engineering Reference
In-Depth Information
is converted into thermal energy for desalination while for June it is 47%. This is due to the
fact that for winter months heat losses from the collector bank, the accumulator tanks and the
evaporator are larger than during the summer period because ambient winter temperatures are
substantially lower than summer temperatures.
Figure 19 shows the monthly values of three major plant performance parameters: the
specific water production in kg/m
2
day, the specific heat consumption in kcal/kg dist. and the
specific power consumption in kWh/m
3
. The specific water production is defined as the rate
of water production per unit collector area. It varies between 43.9 kg/m
2
day and 78.1 kg/m
2
day with the lower values for the winter months and the higher values for the summer
months. The specific heat consumptions is defined as the rate of heat supplied to the
evaporator per unit of water production. It is essentially constant at about 39 kcal/m
3
of
product water. The specific power consumption, defined as the electrical energy required per
cubic meter of product water, varies between 7.08 kWh/m
3
and 8.15 kWh/m
3
with the higher
values typical for winter months and lower values for summer months.
Figure 19. Plant performance parameters for the first six months of 1985.
8. Plant Maintenance and Modifications
In this section, the major maintenance and plant modification activities will be described.
Among the major maintenance activities that had to be carried out regularly are the following:
•
Cleaning the collectors to remove dust and dirt deposited.
•
Inspection for corrosion replacing corroded components
•
Inspect vacuum inside collector glass tubes
•
Monitor scale formation on evaporator heat exchanger tubes and carry out acid
cleaning if necessary
•
Monitor level of water in heat accumulator and add makeup water and anticorrosive
chemical as required
•
Evaporator pump maintenance
•
Monitor pressure difference across seawater intake filters and clean when necessary
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