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Chapter 3
DIMENSIONING
PRODUCTION OF JUST DOMESTIC HOT WATER
The basic calculation for the dimensioning of the solar system for the production of domestic hot water
starts from the identifi cation of the total consumption of the family in question.
On the basis of habits, consumption of hot water can be low, medium or high. Table supplies the indicative
values of daily consumption per person at the various comfort levels and for the household appliances
prepared for direct use with hot water.
Low Comfort: 30 l
Average Comfort: 50 l
High Comfort: 70 l
Washing machine: 20 - 40 l (1 wash)
Dishwasher: 20 l (1 wash)
The surface of the collectors must be dimensioned on the basis of the latitude, inclination of the roof and
orientation of the pitch. Maximum production is obtained with the collector facing perfectly south and
inclined from 30° to 45°.
The following table supplied an indication of the collector surfaces necessary on the basis of latitude.
Area in Italy
Reference values for the dimensioning of the
surfaces of the collectors
North
1.2 m
2
every 50 litres/day
Centre
1,0 m
2
every 50 litres/day
South
0,8 m
2
every 50 litres/day
fi gure 3.2
