Solar Domestic Hot Water
To meet hot water demands, all 52 homes of the Drake Landing Solar Community (DLSC) will be equipped with a stand-alone solar domestic hot water (SDHW) unit that operates with unique, self-regulated solar panels installed on the roof. Each unit is coupled to a power-vent, natural gas water heater.
The design of the DLSC orients the houses in a manner that maximizes solar collection.
The two solar panels located on the roof of each home absorb the sun’s energy to heat a glycol solution that runs from the panels to a heat exchanger in the basement. The glycol is a non-toxic anti-freeze, allowing the system to function during the winter months.
As the glycol passes through the heat exchanger, heat is transferred to the water stored within the hot water tank. On an annual basis, this process results in solar energy supplying up to 60 percent of the home's domestic hot water requirements. When solar energy is not available, the hot water demands are supplemented by a back-up natural gas, power vented hot water unit.
In order for the SDHW unit to meet the DLSC requirements of the Built Green™ Alberta program, on an annual basis it must produce a minimum of 50 percent of the hot water used in the homes. The units for DLSC should reach up to 60 percent. Combined with the higher efficiency power-vent, natural gas water heater and the low water consumption devices in the homes, the 52 solar homes in the subdivision are expected to use 65 – 70 percent less natural gas to heat water as typical new homes. This alone will save one tonne of greenhouse gas (GHG) emissions each year per home.
The SDHW units for DLSC were provided by Enerworks.
Solar Domestic Hot Water Collector Cross-Section