Solar Energy Calculator

Applying this energy calculator you can calculate how much energy an Sunflower solar collector will produce each day/month/year. The application of this energy is depends on you. You can use it for bathing and washing clothes, or central heat a building. Actually one integrated system can have these functions.

You can also apply these values to help you to calculate how much energy you can save by using an Sunflower solar collector.

In order to calculate energy output you need to input the following variables:
Insolation Level - Before the calculation of your energy output, you need to know the value of insolation level at your place. Those values are available at the insolation page. Take note of your maximum and minimun insolation levels throughout the year as well as the annual average value. When calculating potential energy savings, input annual average insolation, and pay attention to the "per year" energy output value.
Energy must be input in the unit of kWh/m2/day. 1 kWh/m2/day = 317.1 Btu/ft2/day

Collector Size - You need to enter the collector size in absorber surface area.
The absorber surface areas of the different tube sizes are as follows:
- 58/1800 = 0.08m2 per tube. So an Sunflower AP 20 tube = 1.6m2 absorber area
- 58/1500 = 0.067m2 per tube
Energy Cost - Enter the consumption of ebergy in the unit of per kWh in your local currency
(may need to convert from m3 or Therms)
1 therm = 29.3kWh = 100,000Btu = 105.5MJ
Natural Gas is 39MJ/m3 = 10.83 kWh/m3
LPG Propane (liquid) = 25.3MJ/L = 7kWh/L
LPG Propane (gas) = 93.3MJ/m3 = 25.9kWh/m3


Insolation Level =
Absorber Area =
Electricity Cost =
$/£/€ per kWh

(click twice)

Energy Output

Per Day = kWh
Per Month = kWh
Per Year = kWh
= Btu
= Btu
= Btu


= $/£/€
= $/£/€
= $/£/€



Please note: 

- The peak efficiency of collector can be achieved only when ambient temperature and water temperatures are the same. During normal using, it can be achieved only in a short period each day, and usually happens when ambient temperatures are high (Such as summer). So during normal using, the solar collector can't always operateing at such a high efficiency. This is the same for all evacuated tubes and flat plate collectors, not only for Sunflower collectors. In order to offer more realistic figures, the above calculations are based on "normal" operating conditions when the difference between ambient temp and manifold water temp is around 30-40oC.

- When compared with other products, please take the above points into consideration. Do not simply apply the peak efficiency values for the energy output, as this will cause inflated figures. IAM values also play an important role in the determination of total energy output from a solar collector.

- Monthly and annual values are calculated by 28 days and 336 days, expect for the days of very low solar radiation.

- Energy output values are approximate values. Actually,the energy output and the efficiency of overall system will depend on installation location, climate, insulation, system configuration and so on. On rainy or heavily overcast days, the energy output will be greatly reduced.

- Energy is generated in the form of heat. In thetransporting and converting of the energy, such as air conditioning or central heating, the energy (heat) will be lost, as no system or insulation can reach 100% efficiency.

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