- What is Solar Heating and Cooling?
- What Are the Types of Solar Heating and Cooling Systems?
- Passive Solar Heating
- Unglazed Solar Collectors
- Transpired Solar Air Collectors
- Flat-Plate Solar Collectors
- Evacuated Tube Solar Collectors
- Concentrating Solar Systems
- How Does a Solar Heating and Cooling System Work?
- How Do You Store Thermal Energy for a Solar Heating and Cooling System?
- What Is the Best Material for Collecting Thermal Energy?
- How Long Does Thermal Energy Last?
- Where Is Thermal Energy Used?
- What Are the Benefits of Thermal Energy?
- What Are the Dangers of Thermal Energy?
- Are Solar Heating and Cooling Systems Efficient?
- How Much Does Solar Heating and Cooling Cost?
After moving into our home, I noticed that the construction of the house was slightly different than what I was used to. It was built in the mid 80s and things were much different for construction at that time. You see, my house is southern facing and in the living room I have large windows and the floor directly under those windows is dark brick.
That’s right…brick flooring inside my house. When I first saw this design I figured that the house was expanded during a renovation and they hadn’t gotten to flooring over it. Well, to my great surprise, that brick is a thermal heater for the house.
The sun would shine through the large windows and heat up the brick causing it to radiate heat throughout the living room and kitchen. I will be honest with you in that it is not very aesthetically pleasing to the eye, but the savings on your heating bill during the winter does give it a sense of useful beauty.
What is Solar Heating and Cooling?
Solar heating and cooling technology collects heat or thermal energy from the sun and uses it for hot water heating, pool heating, and space heating. It can be used for both residential and commercial properties.
Solar heating and cooling collects energy from the sun, which is a renewable resource. It is also a clean source of energy, and by transitioning to solar power, you can reduce your electric bill as well as your reliance on mediums that rely on gas or electricity.
What Are the Types of Solar Heating and Cooling Systems?
There are six different types of solar heating and cooling systems, including passive solar heating and various collector systems. Listed are the types and some common uses for each of them.
Passive Solar Heating
Passive solar heating uses a building’s site, materials, and climate to reduce energy use. It requires properly-oriented windows facing south and materials that are designed to absorb heat. Brick, stone, and tile are often used. Heat is distributed throughout the house by conduction, convection and radiation methods, and the home becomes very energy efficient as a result.
You can add a room to an existing home to take advantage of this system, or use this design when you build a home from scratch like the house that we are currently living in. Another personal application of passive solar heating are the solar showers used by outdoor enthusiasts as it uses the sun’s thermal energy to heat up the water to be used in a passive way.
Unglazed Solar Collectors
These systems are the most common and simplest of the solar thermal systems. This system uses “unglazed” or non-covered collectors to collect the sun’s heat and transfer it to a fluid that is circulated behind it. They are considered non-covered because they do not have a glass covering which makes production inexpensive, but the trade-off is they tend to lose heat.
The most common of these types of systems are solar pool heating collectors. They are usually a dark colored plastic tubing mounted to a roof and the pool water is circulated directly through the tubes and back into the water at a higher temperature.
Transpired Solar Air Collectors
This type of system is somewhat similar to the passive solar setup in that you have a heat conducting material positioned on the south facing of a house or building. The difference is in the use of a circulation fan that pulls the heated air into the ventilation system of a house or building.
This type of system is not as common and could be considered a hybrid type of system due to the intake fan using electricity to run. For a completely solar solution then you would just need to add in enough solar panels to run the intake fan instead of using the power grid.
Flat-Plate Solar Collectors
This system is the same as the unglazed solar collectors, but have the added benefit of using better heat absorbing materials, such as copper, and they are covered in glass to further retain the collected heat energy. These are more expensive to use, but definitely more efficient at collecting the sun’s heat.
This system is mostly used as a compliment to water boilers to reduce fuel consumption and demand, but also can work as a reliable heat exchange system to produce hot air for large buildings during the day.
Evacuated Tube Solar Collectors
As you can tell by the name, this system uses vacuum sealed glass or plastic tubing that surrounds smaller tubes, such as copper, that are filled with a liquid. The liquid is heated and rises to the top where there is cooler water circulating across the top of the tubes. The heat is transferred and the cycle continues.
The use of this technology has greater efficiency and can produce very hot water for on-demand water heating, but is also capable enough to produce enough thermal energy to heat to handle most space heating or cooling applications.
Concentrating Solar Systems
With the use of parabolic mirrors that reflect concentrated sunlight onto a pipe or tube that contains a heat transfer liquid, this system is capable of creating superheated fluids for a wide variety of applications. The overall premise is essentially the same in that the fluid is constantly circulating through the system to provide constant access to hot water.
Most of the uses of this type of system are larger businesses and power companies because superheated water can generate steam for turbines to produce power and heat for buildings.
With each of these systems there is a heat transference that occurs so heat can be collected and used to heat a building just as the heat from a building can be collected by the system and cooled using the same ability.
How Does a Solar Heating and Cooling System Work?
Solar heating and cooling systems collect thermal energy from the sun to use it for heating and cooling. They can also be used for heating hot water and pools.
Solar space heating includes a solar collector, insulated pipes, and a tank. The solar collectors draw thermal energy from the sun’s rays. They heat a non-toxic liquid, water, or air that is circulated throughout the home to provide heat to the rooms. They can also use transpired solar collectors along the building’s exterior wall that allow air to pass through and be heated. The solar heated air can then be channeled through the building’s system.
There are two types of solar cooling systems in use. In a desiccant system, air passes over a drying material, also called a desiccant, which pulls the moisture out of the air. It uses the solar heat to draw the moisture out.
Another type of cooling system, the absorption chiller system, is the most common cooling system. It uses solar water heating collectors and a thermal-chemical process to produce cool air without using any electricity. The major difference between this and electric air is that it does not use a compressor. The compressor is replaced by the absorption of heat into the fluid that is driven through the system.
If you are interested in reading various case studies about solar heating and cooling systems then be sure to visit the Solar Energy Industries Association‘s website.
How Do You Store Thermal Energy for a Solar Heating and Cooling System?
Thermal energy can be stored for later use for a heating and cooling system. It is similar to how a battery stores energy for later use. It can store thermal energy in the form of chilled water, ice, and hot water. Chilled water and ice are used for cooling and hot water is used for heating.
The thermal energy can then be drawn upon when the air conditioning or heat needs to come on. Water storage is usually located underground, whereas ice storage is usually located in a tank. The ice is formed within the tank and stored for later use. This helps reduce the electric requirements of a system because the thermal energy can be accessed at any time.
What Is the Best Material for Collecting Thermal Energy?
There are different materials that can absorb and reflect sunlight. In addition to the type of material, the color of the material plays a role. Materials can absorb sunlight, reflect it, or transmit it. In addition, dark colors tend to absorb light, whereas lighter colors reflect it.
Metals, including copper and aluminum, have high thermal conductivity, so heat spreads quickly through them. They also have very high melting points, which makes them well suited to collect thermal energy. They are able to absorb and transfer heat without melting.
There are a few non-metals, including brick stone and brick, which work well for collecting thermal energy, particularly if they are dark in color. Plastics are not good because they have a low melting point, and wood doesn’t work because it can catch fire. However, for lower demands, plastics can be coated in a reflective material and used. Glass does not absorb thermal energy, but it can trap the heat to prevent it from escaping.
Molten salt can collect thermal energy that is stored in a tank. Salt can hold heat for long periods of time, which makes it useful for collecting thermal energy.
How Long Does Thermal Energy Last?
Thermal energy can be stored for different periods of time depending on how it is stored. Some systems store energy for use just a few hours later, and others store it for days, weeks, or months.
Sensible heat systems are the heating or cooling of air to be used later, and these systems typically store energy for a few hours. Latent heat storage involves a change in phase from solid to liquid or liquid to solid, and these systems can store heat much longer.
Sensible heat is simple and less expensive to use, but it doesn’t last as long. Latent heat offers much greater heat storage capabilities. There are experimental solar communities that use latent heat to store thermal energy in the summer for use in the winter. One is in Alberta, Canada, and the other is in Vojens, Denmark.
Where Is Thermal Energy Used?
Thermal energy is used anytime something is heated. It can be used for cooking, heating your home, heating hot water, and much more.
Solar thermal energy is used when photovoltaic panels collect solar energy to convert it to AC power for your home. It can be collected to heat water that produces steam to operate a turbine that produces electric power.
For home use, solar thermal energy can be used to heat a radiator or floor in the home. It can be used to heat hot water as well.
Thermal energy is incredibly versatile and can be used for a variety of applications. It is clean and renewable, which is good for the environment.
What Are the Benefits of Thermal Energy?
There are a number of benefits to using thermal energy. First of all, it is less expensive than using natural gas. It is a free and clean renewable resource, and it can be harnessed from the sun and converted to power to operate appliances or be used with solar heating and cooling systems. In addition, it has nearly zero emissions, which is beneficial to the environment. It helps to reduce pollution and does not impact global warming.
Thermal energy also reduces the strain on the electric grid. It does a great job of meeting small cooling demands, and it can leave electric energy needs for times when they are necessary. Air conditioning is one of the largest power users out there, and using thermal energy to cut back on power use for air conditioning has significant benefits in terms of reduced costs and reduced pollution.
What Are the Dangers of Thermal Energy?
The real danger in using thermal energy is the risk of being burned by contact with the pipes or material that is storing the heat. However, when it is collected and stored correctly, it can be used to heat hot water and homes and it can cool them and be converted to power as well.
Are Solar Heating and Cooling Systems Efficient?
Solar heating and cooling systems are efficient. They are affordable, and they can significantly reduce both your utility bills and your contribution to pollution. Solar energy is renewable, and it is a clean source of energy.
How Much Does Solar Heating and Cooling Cost?
Residential solar heating and cooling systems cost between $6,000 and $10,000 to install, but there are often credits available from local municipalities. In addition, close to 47% of energy consumption in the home is for heating and air conditioning use. The solar heating and cooling system often will pay for itself in three to four years in terms of the improved home value and savings on your utility bills.