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Solar Thermal Energy

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• Fundamentals of Solar Energy• Introduction to Solar Thermal Systems• Solar Collectors• Power Systems from Solar Thermal

Fundamentals of Solar Energy

• Solar energy is the energy gained by capturing light and heat emitted by the Sun.

• Solar energy refers primarily to the use of solar radiation for practical purposes.

• All renewable energy except geothermal and tidal, derive their energy from the Sun.


Original JPG by Frank van Mierlo


Source: New renewable energy sources, Norway


• Sonora surface = 179,355 km2

• 1% = 1,793.55 km2 = 1,794.55x 106 m2

• State annual average global solar radiation = 5.9 kWh/m2/day• Solar radiation @ 1% Sonora = 10,582x106 kWh/day

• Thermoelectric plants produce 3.57 kWh/liter of fuel oil• A barrel = 159 liters = 567.63 kWh/barrel

• Energy of 1% Sonora surface = 18.64x106 barrels/day• World Oil Production = 94.5x106 barrels/day (October 2014)• Mexico Oil Production = 2.33x106 barrels/day (February 2015)


• Uses of Solar Energy:• Architecture and urban planning• Agriculture and Horticulture ‐ greenhouses• Solar lighting• Solar Thermal• Solar Photovoltaic• Generation of electricity with the Sun

Introduction to Solar Thermal Systems

• Solar Thermal Energy. Take advantage of the sun's energy to produce heat.• Heating a fluid• Cooking food (solar cookers)• Solar drying• Distilled water• Heating buildings• Cooling buildings (absorption systems)• Solar furnaces (casting)• Power generation


• Passive Solar System. Take advantage of the heat of the Sun without mechanisms or mechanical systems.

• Some examples are:• Heating and cooling of buildings• Water heating• Natural lighting• Natural ventilation (indirect solar)


Heating a fluid• Solar collector of liquid (water)

• Solar collectors heat tubes filled with anti‐freeze liquid which transfers heat to a storage tank which preheats the water going to a domestic hot water system.

• This allows the current water heating system at a temperature higher than that of a water well or city ... less energy is required to reach its setpointtemperature.


• Solar collector of gases (air)• Air is used as a medium for heat transfer rather than a liquid.• Solar energy is stored in receivers, which can be filled with gravel, for example.

• The advantage of this system is the absence of corrosion problems, and, unlike a water trap, the problems associated with the freezing and overheating also avoided.

• Air is a rapid reaction via heat transfer to the rock and is a cheap storage medium for heat.

• However, the collectors are not common because of the low storage capacity air and rock.


Cooking food (solar cookers)• A solar cooker is a device which uses the energy of direct sunlight to heat, cook or pasteurize food or drink.


Solar drying• Solar dryers are devices that use solar energy to dry substances, especially food.


Solar water distillation• A solar still is a simple way of distilling water, using the heat of the Sun to drive evaporation from humid soil, and ambient air to cool a condenser film.


Heating buildings


Cooling buildings (absorption systems)

Passive Solar Cooling


Solar furnaces (casting)

Solar furnace at Odeillo, France


Electric power generation

Solar Collectors

• Types of Solar Collectors for Heating• Flat Plate• Evacuated Tube

• Type Solar Collectors for Power Generation• Parabolic trough• Linear Fresnel reflector• Parabolic dish (dish Stirling)• Solar power tower• Solar updraft tower

Solar Collectors

Flat plate collector (liquid)

Solar Collectors

• Domestic Solar Hot Water (DSHW)• Does NOT replace your HW System.• There are some applications in certain locations (depending on the needs of the facility) that can generate what they need simply by using a DSHW system but in today’s modern age it is not common.

Solar Collectors

Passive Active

Solar Collectors

Solar Collectors

Flat Plate Collector (Air)

Solar Collectors

Flat Plate Collector (for pools)

Solar Collectors

The two, 2' x 20' (80 SF) collectors provide about 80,000 BTU's

This lightweight, but heavy‐duty heating system raises the pool water temperature by approximately 10° F (6° C).

Save money on fuel costs and electricity (uses your existing pump). Get more use out of your pool every year by extending the swimming season in the spring and fall.

Solar Collectors

Solar Collectors

• Evacuated Tube

Solar Collectors

Solar Collector Efficiency

Power Systems from Solar Thermal

Parabolic Trough Collector• A parabolic trough is a type of solar thermal collector that is straight in one dimension and curved as a parabola in the other two, lined with a polished metal mirror.

• The energy of sunlight which enters the mirror parallel to its plane of symmetry is focused along the focal line, where objects are positioned that are intended to be heated.


• As of 2014, the largest solar thermal power systems using parabolic trough technology include, the 354 MW Solar Energy Generating System (SEGS) plants in Mojave Desert, California.


Linear Fresnel Reflector• Linear Fresnel reflectors use long, thin segments of mirrors to focus sunlight onto a fixed absorber located at a common focal point of the reflectors.

• These mirrors are capable of concentrating the sun’s energy to approximately 30 times its normal intensity.

• This concentrated energy is transferred through the absorber into some thermal fluid (this is typically oil capable of maintaining liquid state at very high temperatures).

• The fluid then goes through a heat exchanger to power a steam generator.


• Today the largest is located in Murcia, Spain, with 31.4 MW and projected a 300 MW for Florida.


Parabolic Dish (Dish Stirling)• A dish Stirling system uses a large, reflective, parabolic dish (similar in shape to a satellite television dish).

• It focuses all the sunlight that strikes the dish up onto a single point above the dish, where a receiver captures the heat and transforms it into a useful form.

• Typically the dish is coupled with a Stirling engine in a Dish‐Stirling System, but also sometimes a steam engine is used.

• These create rotational kinetic energy that can be converted to electricity using an electric generator.

• The largest project of this type is in Arizona, USA 1.5 MW.


Solar Power Tower• The solar power tower, also known as 'central tower' power plants or 'heliostat' power plants or power towers, is a type of solar furnace using a tower to receive the focused sunlight.

• It uses an array of flat, movable mirrors (called heliostats) to focus the sun's rays upon a collector tower (the target).


• The largest is located in San Bernardino County, California, USA with a capacity of 392 MW. It was completed in February 2014.


Solar Updraft Tower• The solar updraft tower (SUT) is a renewable‐energy power plant for generating electricity from solar power.

• Sunshine heats the air beneath a very wide greenhouse‐like roofed collector structure surrounding the central base of a very tall chimney tower.

• The resulting convection causes a hot air updraft in the tower by the chimney effect.

• This airflow drives wind turbines placed in the chimney updraft or around the chimney base to produce electricity.

https://www.youtube.com/watch?v=XCGVTYtJEFk

https://www.youtube.com/watch?v=0tWlP0knKQU

Solar Thermal Energy

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