Question

the surface area of concentrator type solar heater is 5m2. it can reflect 80% of solar radiation incident while it absorbs the rest. calculate energy concentrated by heaters as it focus in 2 hours if solar energy was delivered to it at the rate of 0.4 kj/m2s

Answer 1

The energy concentrated by the solar heater is 2880 kJ. This is found by calculating the total energy incident on the heater over 2 hours and then determining the energy absorbed which is 20% of the incident energy.

Step-by-step explanation:

The question involves calculating the energy concentrated by a solar heater with a surface area of 5m2 over a period of 2 hours. The solar heater reflects 80% of the incident radiation and absorbs the remaining 20%. Given that the rate of solar energy delivery is 0.4 kJ/m2s, we first need to find the total energy incident on the collector and then the energy absorbed.

The total energy incident on the collector in 2 hours is given by:

• Total energy = Power x Area x Time
• Total energy = (0.4 kJ/m2s) x (5 m2) x (2 hours x 3600 seconds/hour)
• Total energy = 0.4 x 5 x 7200 kJ
• Total energy = 14400 kJ

Since 80% of this energy is reflected and only 20% is absorbed:

• Energy absorbed = 20% of Total energy
• Energy absorbed = 0.20 x 14400 kJ
• Energy absorbed = 2880 kJ

Therefore, the energy concentrated by the heaters is 2880 kJ over the 2 hour period.