User Guide

www.poweroptimal.com Document Version: 2.08
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Directors: RA Fearon, FS Moolman, JJ Theron, DM Weber (Non-Executive), IR Jandrell (Independent)
Company registration number: 2012/099947/07
PO Box 5, Kleinmond, 7195
TABLE 2. ANNUAL AVERAGE NUMBER OF SHOWERS PER DAY
The below table indicates the average number of showers per day for which the system will supply hot water over a year
period for different solar array peak power ratings. (The amount of water heated will vary with weather conditions, by
geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in
summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water
heated on that day. This is only an approximate guide.)
Solar + Elon®
Number of showers per day (based on annual average) for X kW
p
installed solar capacity
Location
kWh/kW
p
/yr
0.8 kW
p
1 kW
p
1.2 kW
p
1.4 kW
p
1.6 kW
p
1.8 kW
p
2 kW
p
2.5 kW
p
3 kW
p
3.5 kW
p
Bloemfontein
1894
2.4
3.0
3.6
4.2
4.8
5.4
6.0
7.5
9.0
10.4
Cape Town
1624
2.0
2.6
3.1
3.6
4.1
4.6
5.1
6.4
7.7
9.0
Durban
1447
1.8
2.3
2.7
3.2
3.6
4.1
4.6
5.7
6.8
8.0
Jhb/Pretoria
1724
2.2
2.7
3.3
3.8
4.3
4.9
5.4
6.8
8.2
9.5
Mbombela
1627
2.1
2.6
3.1
3.6
4.1
4.6
5.1
6.4
7.7
9.0
Port Elizabeth
1565
2.0
2.5
3.0
3.5
3.9
4.4
4.9
6.2
7.4
8.6
Upington
1912
2.4
3.0
3.6
4.2
4.8
5.4
6.0
7.5
9.0
10.5
Saldanha
1623
2.0
2.6
3.1
3.6
4.1
4.6
5.1
6.4
7.7
9.0
The table is based on 6-minute showers at 40 °C and 8 litres/min low flow showerheads. Old showerheads can use up to
15 litres/min and would substantially reduce the number of showers.
Example:
For a solar PV array of 2.5 kW
p
, an installation in Johannesburg would yield about 1724 kWh/kW
p
/yr, or 1724 x 2.5 kW
p
=
4 310 kWh/yr. This would be sufficient for about 6 to 7 showers per day.