This solar water heater system was installed on a two story family residence in north Boise to provide domestic hot water (currently) with the potential integrate hot water space heating (pending improvement).
This system is a common setup employing an evacuated tube solar collector to provide domestic hot water. This design allows the existing hot water tank to remain and be used to store solar heated water. As the solar collector heats up the domestic water it is pumped from the collector to the water tank by a small circulation pump. This source of heated water allows the existing hot water heater tank’s electrical or gas element to remain off. On days when solar energy isn’t available, or during times of heavy usage, the electric or gas elements in the hot water tank will activate, serving as a backup for hot water (as was traditional done).
This 25 tube solar water heater will provide the majority of the summer time hot water demand, and most of hot water in winter. This solar water heater will be able to provide water heating during cloudy or overcast days, but may require the use of traditional gas or electric heating system to produce the required hot water temperature.
The 25 evacuated tube double walled vacuum sealed borosilicate glass solar system is highly durable and very efficient; a UV absorbance rate of 92%. When UV light goes through the second layer of glass it hits an absorber containing three layers in order: aluminum sputtering, steel and copper. Water heated in the solar system is circulated to the water tank by a small pump contained in the control panel mounted near the existing hot water tank.
The pump is operated by integral control logic and turns on when the water in the solar collector is warmer than the water in the hot water storage tank. Remote thermo-couples (heat sensors) which terminate at the control panel monitor water temperature in the solar water heater manifold, and in the cold/hot water lines on the water tank.
Real time temperature data is used to control the function of the solar water heater system and supply solar heated hot water for immediate use or for storage in the existing hot water tank when appropriate.
This residential renewable energy system qualifies for a 30% renewable energy tax credit (dollar for dollar) which is a huge incentive and one which will accelerate the payback period of the solar hot water system.