If you are considering the installation of a solar panel system for your home, it is important to know the main differences between photovoltaic and thermal systems and between on-grid, off-grid and composite ones. Knowing the amount of energy you need and details related to the space will help you establish which of these systems suits you best.
An Armand Energy consultant can help you weigh options and make a cost estimate for each type of system.
There are 2 types of solar installations:
- Photovoltaic installations;
- Thermal installations.
Photovoltaic installations produce electrical energy and they come in 3 types:
- On-grid systems;
- Off-grid systems (independent or autonomous);
- Composite (or mixed) systems.
On-grid Systems (connected to a grid or network)
These are the most used types of photovoltaic solar systems. On-grid systems are connected to the electrical grid and allow the inhabitants of a building to use both solar energy and electrical energy from the network. On-grid systems aren’t required to produce the total of electricity needed for a home.
When there is no need of energy, the solar panels send the electrical energy surplus back into the grid. When a house is in need of energy but the solar panels are not able to provide (in night time or a stormy day), the panel electrical energy is supplemented by electrical energy from the grid. There is no difference in life conditions with a PV On-grid system, with the sole exception that a part, or all, of the electrical energy comes from the sun.
On-Grid System advantages:
- In case of unfavorable weather conditions, energy comes from the national grid;
- A reduced number of components which allows a fast set up of the system;
- A lower price that the ones for Off-grid systems;
- Minimal or no costs when it comes to maintenance and functioning.
Off-Grid Systems (autonomous or independent)
Off-grid systems are often used in remote locations that have no access to utility services. They function independently from the local utility network and supply electrical energy for the house. These systems usually need a battery (to store solar electrical energy for later use, like night time or bad weather) or an auxiliary energy reserve (like a generator) or both. Am off-grid solar system must be sufficiently large to produce 100 percent of the household’s needed energy. Because there is no other source to supplement the needed electricity, electrical energy use must be monitored and kept under the maximum panel and battery power.
Off-grid system advantages:
- Ideal for remote locations that are too far from an electrical grid;
- Have no need of functioning permits.
Mixed or Hybrid Systems
Mixed or hybrid systems are a betterment of On-grid systems, done by adding a back-up battery. The battery is charged by both the grid and solar panels. In case there is a shortage of power, the back-up battery can be started manually or with an automated system to resume providing energy to the house.
Hybrid System advantages:
- A better control of your energy bill. You can use the back-up battery when electrical energy costs are high;
- Autonomy from the grid, You can choose when and how to use energy from the grid;
- Great in case of power outage;
- Managing your own consumption, unused solar energy is stored for later use;
- The safety of never running out of electrical energy.
Solar thermal systems use solar energy in order to generate thermal energy. This energy is then used for heating domestic water, help with heating the household or for heating the water in the pool.
Depending on the technology used for manufacturing them, the panels can be compact and plain or with vacuum tubes that collect solar thermal energy. The vacuum tube panels are more popular due to their high absorption capacity of solar radiation, even on cloud weather, due to their circular shape that allows for a 90 degree angle exposure and the vacuum that insures thermal isolation. Vacuum tubes have also been sought after due to the ease with which elements can be replaced. In case of the plain ones, partial deterioration leads to replacing the panel altogether.
Thermal Installation advantages:
- Reducing the costs for domestic hot water by up to 75 percent;
- An increase in the value of the house, important for selling purposes;
- The panels need little or no maintenance and will produce heat in daytime even at low temperatures or in cloudy weather;
- Reducing dependency from traditional heating systems;
- Photovoltaic On-grid heating systems are connected to the national energy grid and the energy they produce goes into said national grid.