What are the methods of using solar energy?
The main four ways in which solar energy can be used are:
1. Photovoltaic cell system panel or PV
2. Passive solar design
3. Solar hot water
system or (S.H.W)
4. Solar powered
transportation - Powered by PV energy.
Image: Photovoltaic cell system panel or PV technology
1. Photovoltaic cell
system panel or PV
What is solar photovoltaic (PV) technology?
Photovoltaics is a
technology that uses semiconductor materials to convert sunlight into
electricity. This process demonstrates the photovoltaic effect. It is a
technology tested in physics, photochemistry and electrochemistry. Photovoltaic
technology is used commercially for power generation and as photosensors. Solar
energy is converted into electrical energy through the use of photovoltaic
cells to generate electricity. Solar photovoltaic (PV) technology converts
sunlight directly into electricity. Semiconductor materials are used in solar
photovoltaic (PV) diagrams. This technology uses semiconductor materials such
as silicon to convert sunlight into electricity. PV cells or Photovoltaics cell
modules are small units connected together to form a PV array. PV arrays can be
specially installed on roofs, building facades or even on the ground. PV
technology is a clean and renewable way of generating electricity. It produces
no emissions other than power which causes no environmental pollution and
requires no fuel to run. PV systems require relatively little maintenance and
can last for a long lifetime. Whereas silicon, which absorbs light and excites
electrons. These excited electrons create electrical currents that transmit
energy to various devices that are used to move the device.
What are the main components of a PV system?
PV Module: Consists of
semiconductor cells, which convert sunlight into electricity.
Inverter: Converts DC
electricity into AC electricity that can be used in the home or on the grid.
Mounting Structure: PV
modules are mounted fixedly facing the sun.
Backup System
(Optional): Can provide power during cloudy days or night time.
What are the advantages of PV systems?
Clean and renewable
energy source: produces no emissions and does not depend on fossil fuels.
Low maintenance: No
moving parts and long lifespan.
Noiseless: Creates no
noise pollution.
Scalable: Can be used
for any size, from small rooftops to large industrial projects.
Uses of PV Technology:
Power supply to homes
and businesses: PV systems installed on rooftops can provide power to homes and
businesses.
Grid-connected systems:
PV systems can supply electricity to the electricity grid.
Off-Grid System: Can
supply electricity to remote areas without being connected to the electricity
grid.
Portable charger: Can
be used to charge small electronic devices.
Image: Passive solar design
2. Passive solar design:
Passive solar heating
The goal of passive
solar heating systems is to capture the sun's heat within building components
and release that heat when the sun is absent, while maintaining a comfortable
room temperature. The two primary components of passive solar heating are south
facing glass and thermal mass to absorb, store and distribute heat. There are
different methods for implementing these elements.
What is passive solar design and why is it used?
Providing room temperature
control heating or cooling and producing hydrogen. Passive solar design is a
model in which solar energy is used to the maximum. Passive solar design is an
architectural approach to building buildings to improve thermal control,
lighting and natural ventilation. It works without using any mechanical
equipment or electricity. Passive solar design refers to using the sun's energy
to heat and cool living spaces exposed to the sun. When sunlight hits a
building, the building materials can reflect, transmit, or absorb the solar
radiation. In addition, the heat produced by the sun causes air circulation
which is placed in the designed spaces. These fundamental responses to solar
heat lead to design elements, choices, and placement that can provide heating
and cooling effects in a home. Unlike active solar heating systems, passive
systems are simple and do not involve substantial use of mechanical and
electrical devices.
Methods of using passive solar heating
The actual housing is a
solar collector, heat absorber and distribution system. Solar energy enters the
south-facing glass house where it hits the masonry floor and walls, which
absorb and store solar heat, which is then re-radiated at night. These thermal
mass elements are usually dark in color to absorb as much heat as possible.
Thermal mass reduces heat intensity by absorbing energy during the day. Water
containers inside the living space can be used to store heat. However, water,
unlike masonry, requires carefully designed structural structures, and is thus
more difficult to integrate into home design. Direct gain systems use 60-75% of
the sun's energy hitting the window. For the system to work well, the thermal
mass must be insulated from the outside temperature so that the collected solar
heat cannot be wasted. Heat loss is particularly likely when the thermal mass
is in direct contact with the ground or with outside air that is at a lower
temperature than the desired temperature of the mass.
Basic passive solar design or basic solar design
A complete passive solar design has five components:
Aperture/Collector: A
large glass area through which sunlight enters the building. Apertures should
face within 30 degrees of South and should not be overshadowed by other
buildings or trees from 9 am.
Absorber: A solid dark
surface of storage material, such as a masonry wall, floor, or water container,
placed directly in the path of sunlight. Sunlight hitting the surface is
absorbed as heat.
Thermal mass: Retains or
stores heat produced by sunlight on matter. Although the absorber is an exposed
surface, the thermal mass is the material below and behind this surface.
Distribution: It is the
method by which solar heat is circulated from collection and storage points to
different areas of the house. A strictly passive design will use the three
natural heat transfer modes, conduction, convection and radiation exclusively.
In some applications, fans, ducts and broilers can be used to distribute heat
through the house.
Control: Roof overhangs
can be used to shade the aperture area during summer months. Other components
that regulate and/or control overheating include electronic sensor devices,
such as a differential thermostat that signals a fan to turn on; Driven vents
and dampers that allow or restrict heat flow.
Indirect profit
The heat mass is
between the sun and the habitat. Thermal mass absorbs the sunlight it sees and
transfers it to different places by conduction. An indirect gain system will
use 30-45% of the sun's energy by seeing heat mass through adjacent glass. The
most common indirect gain system is a thrombus wall. Thermal mass, a 6-18 inch
thick wall, is mounted approximately 1 inch north to south with single or
double glazing. Solar heat is absorbed by the dark wall of the wall and
accumulates in the wall mass, radiating it to living structures. The solar heat
wall migrates to the center, appearing north of its north during the last week
or early evening. Heat stress occurs on the north side of the inner wall of the
house. Circulating vents at the top and bottom of the thermal storage wall
allow heat to circulate between the wall and the seating area. At night when
the vents are closed, radiant heat from the wall heats the living space. which
gives comfort to those staying at home.
Passive solar cooling
Passive solar cooling
systems effectively absorb unwanted heat, allowing non-mechanical ventilation,
warm interior ventilation for superior cooling air, and moderate heating
control systems to preserve nighttime coolness. Simply put, passive solar
cooling systems include overhangs or shades on south-facing windows, shade
trees, thermal mass and cross ventilation.
Shading
To reduce unwanted heat
gain in summer, all windows should be shaded by overhangs or other devices such
as canopies, shutters and trellises. If an awning on a south-facing window
extends half the height of the window, the sun's rays will be blocked in the
summer, yet still enter the room in the winter. At sunrise and sunset there is
less sunlight on the horizon, so east and west facing window overhangs are not
as effective. Try to minimize the number of east and west facing windows if
cooling is a major concern. Plants can also be used to shade windows.
Landscaping can generally be used to reduce unwanted heat gain during the
summer.
Thermal mass
Thermal mass is used in
a passive cooling design to absorb heat and increase moderate interior
temperatures on hot days. During the night, the thermal mass can be cooled
using ventilation, allowing it to be ready to absorb heat again the next day.
It is possible to use the same thermal mass for cooling in the hot season and
for heating in the cold season.
Free ventilation
Natural ventilation
maintains an indoor temperature that is close to the outdoor temperature, so it
is only an effective cooling technique when the room temperature is equal to or
greater than the outdoor temperature. Climate determines the best natural
ventilation strategy.
In areas where there is
wind during the day and there is a desire for ventilation during the day, open
windows on the sides of the building face the wind and create cross ventilation
in the opposite direction. When designing, place windows on walls facing
prevailing breezes and opposite walls. Wing walls can also be used to create
ventilation with windows in walls perpendicular to prevailing winds. A solid
vertical panel is placed perpendicular to the wall between the two windows. It
accelerates the natural wind speed due to the pressure difference created by
the wing wall.
In a climate like New
England where night temperatures are generally lower than daytime temperatures,
focus on bringing in cool air at night and then closing the house to keep out hot
outside air during the day. Mechanical ventilation is one way to bring in cool
air at night, but conductive cooling is another alternative.
Convective cooling
The oldest and simplest
form of convection cooling is designed to bring in cool night air from outside
and push warm indoor air outside. If there is a night breeze, high vents or
exposed sides (away from the wind) close to the ceiling will allow warm air to
escape. Low vents on the opposite (windward) side will allow cool night air to
enter to replace the warm air.
In areas where there
are no strong winds, it is still possible to use convective cooling by creating
thermal chimneys. Thermal chimneys are designed around the method that warm air
rises; They create a warm or warm zone of air (often through solar heat gain)
and have a high external exhaust duct. Hot air exits the building through high
vents and cool air enters through low vents.
There are many
different methods to create the heat chimney effect. One is an attached
south-facing sunroom that flows upwards. Air is drawn from the living space
through a connection of lower vents to exhaust through the upper vents in the
sunroom (upper vents from the sunroom to the living space and any operable
windows must be closed and the sunroom thermal mass wall must be shaded).
Passive solar design can help reduce home heat costs and create more
comfortable living spaces.
Principles of passive solar design:
Maximize use of light
and heat: Maximize use of sunlight by using south-facing windows, roof
overhangs, and light reflective surfaces.
Heat retention: Heat is
retained by using high-quality insulation in walls, ceilings and floors.
Natural ventilation:
Natural ventilation is improved by careful placement of windows, vents and
chimneys.
Provide shade: Provide
shade from excess sunlight by using plants, pergolas, and awnings.
Uses of Passive Solar Design:
Accommodation: houses,
apartments and condominiums.
Commercial buildings:
offices, schools, and hospitals.
Industrial buildings:
factories and warehouses.
Agricultural buildings:
greenhouses and animal husbandry buildings.
Passive solar design
uses the sun's heat to regulate the temperature of the room. This is done by
using proper instructions, building materials and landscaping. Some examples of
passive solar designs include:
South-facing windows:
These windows help trap the sun's heat inside during the winter.
Overhanging: These
projections help block high-quality sunlight in summer.
Plants: Properly placed
plants can be used to provide shade in summer and let in sunlight in winter.
Image: Solar Hot Water or SHW
3. Solar Hot Water (S.H.W)
Water heating and
building temperature control. "SHW" is an abbreviation of Solar Hot
Water. It is an eco-friendly and sustainable technology that can be used in any
climate that uses solar energy to heat water. Solar water heating system
consists of a storage tank and solar collector. In this process, solar panels
absorb sunlight and convert it into heat. This heat is then used to heat water,
which is stored in a specially designed storage tank. Solar water heating (SHW)
uses the sun's heat to heat water. It works using a tank and a collector. The
collector is usually installed on the roof and absorbs the sun's heat. This
heat is then transferred to the water stored in the tank. The SHW system is an
environmentally friendly alternative to gas or electricity powered water
heaters. It can also help reduce water heating costs.
How SHW works:
Direct Circulation System
Integral Collector-Storage Passive System Pumps circulate household water
through the collectors and into the home. It does well in climates where it
rarely freezes.
Indirect circulation system
The pumps circulate a
non-freezing, heat-transfer fluid through the collector and a heat exchanger.
It heats the water which then flows into the house. It is more popular in
climates prone to freezing temperatures.
A large flat panel
called a flat plate collector is connected to a tank called a solar storage
water heater by two pipes. One of these pipes runs through a cylindrical pump
to the bottom of the tank, where it turns into a coil called a double-wall heat
exchanger. This coil passes through the tank and back to the flat plate
collector. Antifreeze fluid circulates only through this collector loop. Two
pipes are connected to the water heater tank; One supplies cold water to the
tank and the other sends hot water to the house
Sunlight Absorption:
Solar panels absorb sunlight and convert it into heat.
Heat transfer: This
heat is then transferred to the solar heat collector through a liquid (eg
glycol) or air.
Water heating: In a
solar thermal collector, the liquid or air exchanges heat with the water,
heating it.
Water Storage: The hot
water is then stored in an insulated storage tank.
Usage: When required,
hot water is drawn from the tank and used.
Different types of S.H.W
Fluid-based: In this
type of system, fluid (such as glycol) is used to transfer heat.
Air-based: In this type
of system, air is used to transfer heat.
Vacuum tubes: In this
type of system, vacuum tubes absorb sunlight and convert it into heat.
What are the methods of solar water heating?
There are various
methods for heating water using solar energy. For example:
Solar Water Heater:
This is the most common
method. A collector installed on the roof absorbs sunlight and transfers the
heat to water stored in an insulated tank. This system can provide hot water to
homes or businesses.
Solar Thermal Pump:
This is a more advanced
method that works without electricity. Solar panels absorb heat from sunlight
and heat a liquid. This fluid flows through a heat pump which increases the
temperature of the water. This method is more efficient than traditional solar
water heaters.
Solar concentration systems:
In these methods,
sunlight is focused into a small area using mirrors or lenses. This focused
sunlight can heat the water quickly. These methods are typically used for large
space heat control needs, such as swimming pools or commercial establishments.
Solar cookers:
In these methods, food
is cooked using sunlight. There are different types of solar cookers, including
box-type cookers, parabolic cookers, and solar bag cookers. These cookers are
eco-friendly and beneficial for those living in remote areas as they do not
depend on electricity or gas.
Overall, SHW is an
environmentally friendly and sustainable technology that can help reduce your
water heating costs.
Image: Solar powered transport
4. Solar-powered transportation
How does solar-powered transportation work?
Solar-powered vehicles run using energy from sunlight in several ways:
Direct Solar Energy:
Solar panels are
mounted on the roof or body of the vehicle. The panels generate electricity by
absorbing sunlight. This electricity is stored in a battery and used to run the
motor. This method is common in small vehicles, such as scooters and bicycles.
Solar-Hybrid:
These vehicles have a
traditional engine and a solar power system. Solar energy charges batteries and
helps drive electric motors. Traditional engines are used during long journeys
or low sunlight. This method is used in hybrid cars, buses and trucks.
What is solar-thermal? How does solar thermal work?
Solar-thermal:
Solar-thermal is the
process of converting sunlight directly into heat. This conversion is done
using different technologies.
Some examples of solar-thermal technology:
Solar water heater:
Sunlight heats the water directly or heats the water tank using a heat
absorbing fluid.
Solar power plant:
Sunlight heats the heat-absorbing fluid, which produces steam. This steam
drives turbines that generate electricity.
Solar cookers: Food is
cooked using sunlight.
Solar Desalination:
Fresh water is made from salty water using sunlight.
How Solar-Thermal Works:
Solar Collector:
Absorbs sunlight and generates heat.
Heat Absorbing Fluid:
Absorbs heat from the collector.
Heat Storage: Heat is
stored in an insulated tank.
Use of heat: Heat is
used for various purposes, such as heating water, generating electricity,
cooking food, or making fresh water from salt water.
Advantages of solar-thermal:
Clean and renewable
energy source: produces no emissions and does not depend on fossil fuels.
Reduces Energy Costs:
Can reduce electricity or fuel bills.
Less impact on the
environment: Reduces pollution by reducing the use of fossil fuels.
Low maintenance: No
moving parts and long lifespan.
Disadvantages of solar-thermal:
Initial costs can be
high: Installation requires significant money.
Space Requirement:
Adequate space is required for the collector and storage tank.
Production is less on
cloudy days: Production is reduced if there is not enough sunlight.
In these vehicles
sunlight is converted into heat and that heat is used to run the engine.
Sunlight is focused using mirrors or lenses. This method is still under
development, but is feasible for large vehicles, such as ships and airplanes.
Most of the solar powered vehicles seen include solar rickshaws, electric buses and solar boats. Total installed solar capacity is now up to 161 GW, with solar capacity projected to increase by 23% by 2024, bringing total output to about 6.8% of all electricity. By the end of 2024, renewable solar capacity is expected to account for the largest share of growth at around 58%, followed by battery storage at 23%2. Global installations of photovoltaics (PV) are expected to grow to 400 GWdc in 2024 and 590 GWdc by 2027. China has installed around 260 GWdc of PV panels in 2023-24.