Solar hot water panels can be highly efficient, converting about 80% of the energy that hits them into heat. Even on a cloudy day, they will produce some hot water, especially when they are oriented as close as possible to the south to take maximum advantage of the sun's rays.
They can be used to provide at least a portion of the hot water you use for showers, dishwashers, clothes washers, farm operations and even in-floor heating. A typical system consists of:
- A solar collector that can be mounted on roofs, walls or the ground
- A heat exchanger that extracts the heat that has been gathered
- A pump
- A storage tank for the heated water
Freeze-protected solar water heaters will keep generating hot water even when the mercury dips well below zero.
Conversion of sunlight to heat is one of the most efficient, cost-effective and widely applicable means of generating renewable energy. There are many methods, technologies and brands form which to choose. However, in the Eastern Ontario climate, all systems that operate year-round must be freeze protected.
Leading types of solar water heating systems use:
- Flat Plate (or Glazed) collectors – flat panels with glass and a flat, black metal plate with circulating fluid to capture and transfer heat
- Evacuated Tube collectors – large evacuated tubes, like Thermos bottles, with metal plates inside and a means to transfer captured heat. The vacuum acts as an insulator to prevent losses.
Solar Collector Parts
- Collector manifold
- Glass wool insulation
- Copper header pipe (liquid flow)
- Stainless steel mounting frame
- Evacuated tube (solar absorber)
- Heat transfer fin and heat pipe
Step 1: Sunlight is absorbed inside the evacuated tube causing it to heat up.
Step 2: The heat pipe inside the tube carries this thermal energy up to the manifold box.
Step 3: Fluid circulates from the storage tank up through to the header pipe and extracts the energy from the hot heat pipe tips.
Step 4: The newly heated fluid circulates back to the storage tank where it can be used and the cycle begins again.
- Unglazed collectors – large polymer panels typically used to heat pool water directly. These systems do not have freeze protection and must be drained seasonally.
Commercial Solar Hot Water Heating with EcoGen Energy
Solar water heaters - also called solar domestic hot water systems - can be a cost effective way to generate hot water for any building. A well-insulated solar storage tank will have an additional outlet and inlet to be connected to and from the collector. The solar collector preheats water before it enters the conventional water heater. This initial heating of cold water is the most energy consuming step in a conventional water heating process. Putting a solar water heater in place to fulfill this part of the process can save up to 70% of a building's water heating costs.
EcoGen Energy has installed several commercial SDHW systems, in Kemptville, Ottawa, Perth, Merrickville and in other areas in Eastern Ontario.
Residential Solar Domestic Hot Water (SDHW)
Since some 20-30% of the average family's household energy is spent on hot water for showers, washing, dishes and cleaning, there is a significant potential for savings in having a Solar Domectic Hot Water system (SDHW).
Solar Domestic Hot Water (SDHW) systems:
- Provide more than 50% of the energy used each year for hot water.
- Reduce the impact of increases in energy prices.
- Reduces the dependence on Fossil Fuels and, therefore; reducing your impact on the environment.
- Require very little maintenance and have a life expectancy of 20-30 years.
- Offer a visible sign of a high level of responsibility, environmental awareness and commitment.