Solar Heat for Industrial Processes

Solar Heat for Industrial Processes

• Industries worldwide use heat, making industrial processes a very attractive avenue for solar energy applications
• Solar energy helps significantly reduce fuel costs
• Solar energy decreases environmental impact via reduced carbon emissions
• Industrial applications need temperatures ranging from near-ambient to levels for low-pressure steam, below 400°C, which solar thermal collectors can provide
• Fossil fuels are dispatchable, meaning solar heat must be stored to achieve dispatchability
• Industrial processes using solar heat need adjustment flexibility, using heat only when the solar resource is available
• A small storage solution alongside industrial process modifications is often the best solution
• Industrial primary energy consumption breaks down to approximately 40% natural gas, 41% petroleum
• Solar thermal deployment aims to cover around 33% of energy needs by 2030

Determining the Right Solar System

• Determining the most suitable solar system requires knowledge of temperature, working fluid and their efficient transfer
• Hot steam is suited to concentrating collectors working above 100°C
• Hot water is required at temperatures significantly over 50 to 60°C, often for liquid-based flat plate collectors
• Potential industries include food production, desalination, chemical processing, textile industries, and beverage production

Process Applications and Temperature Requirements

• Solar heating technologies can address approximately 30% of industrial heating demand
• Solar heat is supplied using heated water, steam, or air
• Industrial heating needs fall into three temperature ranges:
• Below 80°C, flat plate solar collectors are effective
• From 80-250°C, concentrating collectors are necessary
• Above 250°C, imaging concentrated systems are needed

Identifying Suitable Solar Thermal Energy Systems

• Key factors to identify include the solar resource, temperature, schedule, capital, and operational costs
• Free tools exist to find the amount of solar radiation information based on specific location
• Assessing a solar thermal application requires knowledge of the existing schedule, requirements, seasonal and daily variations, and the overall process flexibility

Economic Aspects

• Solar heat applications lead to fuel deduction cost
• Deploying solar collectors involves high up-front capital costs, but operational costs are lower
• Industrial applications typically include auxiliary energy supply and useful energy to reduce auxiliary fuel consumption
• Insulation against fossil fuel price shocks

The Power of Wind

• Winds result from pressure differences across regions
• Regions that experience strong wind conditions for a useful period are of interest
• Wind is simply air that is in motion
• Wind energy is based on kinetic energy from the movement of air with mass
• Wind energy is converted to mechanical force or used to generate electricity
• Wind patterns form when the sun heats parts of the atmosphere differently

Thermal Expansion

• Warmer air expands, leading to lower pressure compared to cooler regions
• Air flows from high to low pressure, creating wind

The Sea Breeze

• Warmer air expands, creating lower pressure in warmer areas compared to cooler ones
• Air moving from high to low pressure is what defines wind.
• Warm air above the land expands and rises
• Cooler air from the ocean moves inland, creating a sea breeze

Valley and Mountain Breezes

• Valley breeze: The valley floor warms during the day, and low-density air rises up surrounding mountain slopes
• Mountain breeze: At night, denser cool air slides down the slopes and settles in the valley

Global Wind Patterns

• Global surface winds blow from the poles toward the equator, which causes the warm air to rise
• Cooler, denser higher pressure air from the poles displaces warmer surface air
• In the upper atmosphere near the equator, air flows back toward the poles
• The net result is a global convective circulation with surface winds from northern hemisphere

How Wind Turbines Work

• Wind flows across the blades creating lift, powering the blades to turn
• Turning blades convert wind energy to low-speed rotational energy, causing gears to turn
• Gears spin a generator, turning the rotational energy into electricity
• Electricity generated is sent to the electrical grid for public use

Wind Energy Advantages

• Wind produces no air, water, or thermal pollution and does not require fuel transport or waste disposal
• The technology for harnessing wind energy is mature
• Wind power can supply electricity to individual homes or buildings without grid connection
• Wind can generate power for numerous people when larger turbines are connected to the grid
• The amount of energy wind turbines capture is high, but material and energy requirements for the turbine manufacture is low
• Well-designed wind machines and good wind power locations make the advantage of wind power more clear

Wind Energy Disadvantages

• Sustained winds above 7 mph are optimal, meaning wind farms are on coastlines or mountain ridges
• Wind farms require large areas, potentially thousands of acres
• Potential environmental damage
• Noise pollution
• Vibrations may disrupt TV and cell phone service

Harvesting Biomass

• Mankind has used fire for heat since ancient times
• Biomass is organic material of both plant and animal origin
• Biomass contains stored energy from the sun itself
• Plants use photosynthesis to absorb sun's energy
• Chemical energy in plants goes into animals and people through consumption

More on Biomass

• Biofuels are renewable because they regrow
• Biofuels include materials from both plants and animals like whale oils
• Examples include wood, crops, manure, garbage
• Burning wood is most popular and releases chemical energy
• Other biofuels include peat, biodiesel from cooking oils, and alcohol derived from corn and plants
• Wood and paper industries use wastes for steam and electricity

Types of Biofuels

• Methane gas (biogas) or transportation fuels like ethanol and biodiesel is extracted
• Corn and sugar cane are fermented to produce transportation fuel, ethanol
• Biodiesel is produced from what is left over of food production with vegetable oils

Using Biofuels

• Biofuels are made from biomass
• Biofuels are blended with petroleum fuels (gasoline, diesel, etc) but can run stand-alone
• Ethanol and biodiesel can be expensive replacements, both are cleaner burning
• Ethanol and biodiesel can reduce the effects of fuel pollution
• Ethanol is an alcohol fuel made from sugars in grains, sugar beets, etc.
• Biodiesel comes from vegetable oils and fats
• Biodiesel can be used in diesel engines without modification
• Biodiesel, a safe and biodegradable replacement, also reduces air pollutants

The Byproducts of Biofuels

• Burning biomass releases carbon dioxide, a greenhouse gas potentially leading to acid rain
• Growing biomass crops captures a nearly equivalent amount of carbon dioxide from the atmosphere
• Burning wood produces pollutants such as carbon monoxide and particulate matter
• Adding clean-burning technology to wood-burning fireplaces and stoves can reduce the production of pollutant
• Collection requirements have to meet certain government standards.

Burning MSW

• Burning MSW reduces landfill waste
• Harmful gases and particles are prevented from being released and the remaining ash properly disposed
• Collecting and using biogas reduces methane released into the air
• Collection needs to be processed to be put into natural gas pipelines

Bioethanol vs Biodiesel

• Bioethanol benefits: blending reduces toxic pollutants, yet it causes evaporative emissions
• Bioethanol drawback: it releases carbon dioxide, a greenhouse gas
• Biodiesel benefits: less polluting than petroleum diesel and there are lower emissions.
• Biodiesel Drawbacks: contains nitrogen oxide emissions and has almost no sulfur, and can help reduce sulfur in diesel fuel