Vermont Residential Solar Installations
Grid-tie PV systems operate in conjunction with the utility grid to achieve optimal efficiency. When the sun is shining and your solar PV system is producing electricity, the first priority is to power your household appliances. If a surplus of electricity is being produced, the solar inverter feeds any excess electricity back to the utility grid, making your utility meter spin backwards. This builds up a credit with your electricity company, reducing your bill, as well as increasing the amount of green energy on the utility grid. If not enough electricity is being produced by your solar electric system to power your household appliances, power is brought in from the utility grid to fill in the gap. All of this happens automatically without any need for intervention from you.
Direct grid-tie systems do not include batteries. This increases system efficiency as well as reducing equipment and installation costs. These systems use battery-less inverters that are not compatible with battery banks. Therefore, direct grid-tie systems cannot provide power to your household appliances during power outages. If providing electricity during a power outage is a priority, a grid-tie with battery back-up system can be installed. This system has the benefits of being grid connected to sell excess electricity, as well as providing back up power. Direct grid-tie systems can also be retrofitted with batteries for backup capability.
Solar Hot Water
Solar hot water systems use the energy embodied in sunlight to heat water directly for domestic hot water, space heating or other hot water needs. This is achieved by the use of solar hot water collectors connected to one or more hot water storage tanks by piping. A pump is used to circulate a heat transfer fluid through the collectors, allowing it to heat up, and return the heated fluid back to the storage tank. A heat exchanger at or in the storage tank is used to transfer the heat in the transfer fluid to the water in the storage tank. The cooled heat transfer fluid is then returned to the collectors and the process starts all over again.
Solar hot water systems usually include two tanks, one to store the solar heated water and one to provide backup water heating during cloudy or cold periods. Most often, your existing hot water tank will function as the backup tank. The output of the solar storage tank is piped to the input of the backup tank, so any water entering the backup tank has been preheated by solar energy, giving you a significant energy savings. For homes with low hot water usage, a single tank can function as both the solar storage tank and the backup tank with good results.
Off-grid solar electric systems can provide power equal to or surpassing the quality of grid service to a remote home location, often at a fraction of the cost. Larger battery banks are used in conjunction with optional backup generators to provide power throughout the year. Off-grid systems use battery based inverters as well as solar charge controllers to efficiently store and convert solar energy to power your off-grid home.