physics

In a solar water heater, energy from the Sun is gathered by water that circulates through tubes in a rooftop collector. The solar radiation enters the collector through a transparent cover and warms the water in the tubes; this water is pumped into a holding tank. Assume that the efficiency of the overall system is 28.0% (that is, 72% of the incident solar energy is lost from the system). What collector area (in square meters) is necessary to raise the temperature of 450 L of water in the tank from 18°C to 50°C in 2.8 h when the intensity of incident sunlight is 520 W/m2? The specific heat of water is 4186 J/kg·K. The density of water is 1.00 g/cm3.

  1. 👍
  2. 👎
  3. 👁
  1. The intensity of sun light falling on the earth = I'
    Let area of the plate = A
    Power received by the plate, P = I'A
    Efficiency of the over all system = 28 %
    The power given to the tank is given by
    P = 26% * I' A = 0.28 I'A...........(1)
    m= mass of 450 L of water
    S =specific heat of water = 4186 J/kg·K
    4.186 J/g.K
    ΔT = temparature difference = 32 deg C
    The energy needed to raise the temp of water from 18 to 50 C is

    Q = mSΔT = J
    4.186*(450*10^3)*32
    =60278400 J
    power in put needed
    P ' = Q / 1.0 * 60*60 sec
    P =60278400 / 2.8*60*60 sec
    P' = 5980 W -----(2)
    From the equations (1) and (2) we have
    0.28 I'A = 5980
    A =5980/(0.28*520)
    A = 41 m^2

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. The Water Cycle Quick Check Answers!

    Here are the answers for The Water Cycle Quick Check. I can assure you that these answers are correct. Keep in mind that sometimes, the orders of the questions change. An X will be by the correct answer each question! Which term

  2. Solar Energy Please Help

    a) Family Smith has already installed PV in their house. Now, they also want to cover their needs for warm water with solar energy. For this, they consider having a solar thermal water heating system. Considering that the need for

  3. math

    A water heater has a diameter of 18 inches. It sits in a drain pan that has a diameter of 22 inches and a height of 2 inches, as modeled in the diagram below. Water that leaks out of the water heater sits in the drain pan. Which

  4. Physics

    An electric heater which produces 900W of power is used to vaporize water. How much water at 100c can be changed to steam in 3 mins by the heater? (Heat of vaporization=2.26×106j/kg, specific heat capacity of water=4.2×103

  1. physics

    How long would it take a 1 200 W heater to melt 1.00 kg of ice at -12.0°C, assuming all the energy from the heater is absorbed by the ice? (Assume the specific heat of the ice is 2 090 J/kg · °C and the latent heat of fusion of

  2. Physics

    An immersion heater of resistance R converts electrical energy into thermal energy that is transferred to the liquid in which the heater is immersed. If the current in the heater is I, the thermal energy transferred to the liquid

  3. physics

    An electric heater used to boil small amounts of water consists of a 25-Ω coil that is immersed directly in the water. It operates from a 60-V socket. How much time is required for this heater to raise the temperature of 0.50 kg

  4. Physics

    A 210W heater is placed in 2KG of water. What temperature rise is produced if the heater is switched on for 200 seconds?

  1. Science

    "Most of the solar radiation is absorbed by the atmosphere and much of what reaches the earth's surface is radiated back into the atmosphere to become heat energy." What can you conclude about heat energy? Most of the sun's energy

  2. physics

    The recovery time of a hot water heater is the time required to heat all the water in the unit to the desired temperature. Suppose that a 62-gal (1.00 gal = 3.79 x 10-3 m3) unit starts with cold water at 11 °C and delivers hot

  3. Science

    Which of the following is a problem with using solar power as a main source of energy? A. People do not yet have the technology to use solar power*** B. The sun is not close enough to provide solar energy C. Power from solar

  4. Science

    The Hoover Dam is a hydroelectric power plant that converts the energy of falling water into electricity. Which of the following determines the amount of potential energy of the water stored in the reservoir of the dam? Choose all

You can view more similar questions or ask a new question.