How Trendsetter Solar Water Heating System Works
A. Solar collectors
Trendsetter© Evacuated Tubes
B. Solar Storage tank
Non-pressurized insulated water storage tank
C. Heat exchanger
24 sq ft of copper finned tubing ¾” inside diameter
D. Solar pump
Pumps water through solar panels
E. Solar controller
Turns solar pump on and off automatically
F. Tempering valve
A safety device to cool down the solar hot water if necessary
G1. Existing water heater
Use existing water heater or replace with tank-less water heater (G2)
H. Fill valve
Used to maintain water level in the solar tank
I. Vacuum breaker/breather
Allows for drain down of solar collector and atmospheric pressure in tank
The storage tank contains tap water. One sensor is mounted at the solar collector and one sensor is installed in a “dry dip tube” inside of the storage tank. When the solar collector is hotter than the water in the storage tank, the solar pump slowly circulates the tank water through the solar collector on the roof. The water in the storage tank will gradually rise in temperature. The water will rise 5°F-10°F in temperature between the time the water enters the solar collector and the time it leaves the solar collector.
When hot water is used in the house, the cold water is pre-heated as it courses through the heat exchanger immersed in the solar heated water stored in the insulated storage tank. If the water temperature exiting the heat exchanger is below the desired 120°F standard water heater set temperature output, the tank-less water heater will flash on to boost the water temperature.
For example if the water temperature pre-heated by the solar, is 100°F the tank-less unit will provide just enough energy to boost the pre-heated water an additional 10° to 20° If the solar water in the tank 160°F, cold water will be drawn through the heat exchanger in the solar storage tank through the tank-less water heater with no additional energy input from the tank-less water heater.
After leaving the tank-less water heater the 160°F water will be automatically mixed with cold water at the tempering valve to supply the desired 120°F water temperature to the fixtures. This device prevents scalding temperatures from reaching the hot water fixtures.
The solar collectors will provide optimum solar energy over the year if installed as close to south and tilted to equal the degrees latitude of the house location. However for maximum space heating performance during the winter heating season, the solar collectors should be tilted more vertical e.g. latitude +20 degrees.
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