Solar Energy

What is Solar Energy?

The sun’s energy is converted into thermal/ electrical energy. This type of energy is the cleanest and comes in large quantities all over the world. Solar technologies harness the sun’s energy converting it to multiple uses such as generating electricity, providing light, heating water for domestic, commercial, or industrial use. Solar energy can be built as distributed generation (located at or near the point of use) or as a utility-scale solar power plat (similar to traditional power plants). Both methods can also store energy they produce and distribute after the sun has set [7].

Distributed Generation

Distributed generation, also known as on-site generation or decentralized generation [8], supplies power for a specific building or facility [9].

Utility-Scale Solar Power Plant

A utility-scale solar power plant sells the power generated directly into the electrical grid instead of a specific facility [9].

How is it Harnessed?

Photovoltaics

Generates electricity directly from sunlight through an electronic process which can be used to power many objects/ items (e.g. calculators, road signs, homes, large commercial businesses, etc.) [7]. “When sunlight strikes the photovoltaic (PV) module (made of a semi-conductor material) electrons are stripped from their atomic bonds. This flow of electrons produces an electric current. PV modules contain no moving parts and generally last thirty years or more with minimal maintenance.” [11].

Solar Heating and Cooling (SHC)

Collects thermal energy from the sun and provides hot water and space heating and cooling for residential, commercial and industrial applications. Some ways to collect this energy is by flat plates, evacuated tube, Integral Collector Storage (ICS), thermosiphon and concentrating [11].

Concentrating Solar Power (CSP)

Uses mirrors to concentrate the sun’s thermal energy to power a conventional steam turbine, creating electricity. The thermal energy created in the CSP plant can be stored and distributed when needed regardless of time of day. In the United States, over 1,400 MW of CSP plants are operational. CSP plants are normally located in places with access to the most intense direct sunlight and contiguous parcels of dry, flat land [11].

Technologies for Solar Power

Passive Solar Gain

For passive solar gain, orient the house so the main rooms are facing south, have large windows on south side, small windows on north side, use building materials that store heat by adding “thermal mass” to the house, and have the lay out housing developments so that buildings do no over-shadow each other [5]. To find more information relating to passive solar design click here.

Solar Thermal Panel

This is a black surface that absorbs light, heats up and transfers the heat into a working fluid which moves it to a place where it is useful (i.e. hot water store, swimming pool, specific spot for heating in a building, etc.) [5].

Concentrated Solar Power

Concentrated solar power (CSP) can create higher temperatures due to the sun’s rays being concentrated by mirrors. These only work in direct sunshine so they are only used in areas benefiting from sunny climates [5].

Flexible Organic Photovoltaics

These were created by integrating a network of elastic additives to make the electrically active material less delicate as well as augment the material with little to no loss of current flow [12].

Enhanced Solar Water Heat Pipes

These pipes will improve the efficiency on converting solar energy directly to heat with a system’s operating temperature beyond 250 degrees Celsius whereas normal pipes range from 80 – 120 degrees Celsius [12].

Solar-Powered Pavement

This technology is still in testing along Route 66 (America’s historic interstate highway). It was first used on sidewalks which used thermal heating to melt snow as well as LED bulbs that light the roads at night. This technology can help offset a community’s reliance on the grid and decrease its carbon emissions [12].

Current and Upcoming Materials in Solar Cell Technologies

Crystalline Silicon

It’s a combination of high-efficiency crystalline photovoltaics and hybrid tandem III-V/Si solar cells. These solar cells are an alternative low-cost solution with highly efficient materials. They can harvest solar energy from both sides of the panel with 11% more efficiency compared to standard panels [6].

Thin Films

Second-generation thin-film solar cells are a narrow design (35 times smaller light-absorbing layers compared to standard Si-panels) that are light weight, flexible, and have an easy installation process. The materials consist of cadmium-telluride (CdTe), amorphous silicon, copper-indium-gallium-selenide (CIGS), and gallium-arsenide (GaAs). Although CdTe has a toxicity concern due to the cadmium, the CIGS solar cells are a highly efficient and economic option for residential and commercial installations with an efficiency up to 21% [6].

Perovskite Solar Cells

Perovskite solar cells (PSCs) are a hybrid metal halide that carry a low price, thinner design, low-temperature processing, excellent light absorption properties (good performance under low and diffuse light), flexible, light weight, and semitransparent. These are not commercialized yet due to the stability and durability issues they currently have but when combined with crystalline silicon, they can be as efficient as 28% under laboratory conditions [6].

How Solar Energy Relating to Buildings

Why Should You Use Solar Technologies for Buildings

• • Increases energy consumption [13]
  • Environmental consciousness
  • Global climate change
  • CSR implication/ advantage for corporate buildings
  • Attraction towards cleanest, renewable energy
  • High social value and an increase in the value of the property
  • Unlimited resource
  • Low environmental impact
  • Energy independence
  • Multipurpose
  • Ability for Additions
  • Portable

Advantages in a Building

• • Improves heating and cooling system’s efficiency by 30% by proper installation of a new HVAC system while reducing operational costs by 90% with a solar water heater [13]
  • Low-Emissivity (Low-e) Window Glazing reduces space cooling by approximately 40% and a light-coloured roof reduces a roof’s temperature because it absorbs less than 50% of the solar energy)
  • When using energy efficient lights and appliances, the energy used can reduce by 20-30%