The images below provide a demonstration related to stand alone applications without a battery bank. More information is provided in the adjacent text to the image.
A stand alone application is when there is not a battery bank in the system. Each demonstration shows a grid tied inverter, but an inverter is not required for operation. The grid tied inverter has the advantage of providing a way to use solar power once the heating device is done, by feeding it back to the grid for credit from the utility company (when available). A properly matched solar array to heat demands makes the inverter less likely to be financially advantageous.
It is important to note the size of the solar array AND the environmental factors (Sun, shading, temperature, etc) determine the amount of solar power available. For more information relating solar power to heat (BTUs), see the Facts [+] Math page.
Click the image to start the animation. Click while running to pause or click once complete to restart.
Device Installation
for domestic hot water
What the animation shows:
PV panels are installed in a location with optimal Sun exposure. For demonstration purposes, a roof mount system is shown, but any configuration is acceptable.
PV power wires are run from the panels to the device. Wire gauge and conduit based on operating conditions and environment. See your local building codes for more information.
Heated water stored using a dedicated heating loop. A standard electric hot water heater has a hot port, cold port, thermal relief port, cleanout port. By using the hot port and cleanout port, the device can easily be installed without effecting the operation of the electric hot water heater. Other installation options are possible. If a dedicated loop cannot be used, such as when the hot and cold ports on the tank are used, an isolation valve may be required for the device.
Wiring from device to inverter/utility meter is done to allow the device to bypass the power to the inverter to be sold on the grid. The inverter is not required for the device to operate.
Wiring from house to the pole is shown for conceptual purposes only. Unless the residence is a new construction, the wiring to the pole would already be in place.
What the animation doesn’t show:
Combiner box and/or circuit breaker panel may be required. This would be installed as close to the panels as possible.
Inline strainer is recommended if cleanout port on electric hot water tank is used. This is to prevent sediment at the bottom of the tank from being pumped through the heating loop.
Electric hot water heater thermostat should be lowered to allow the device to be the primary heat source during daylight hours.
Device with a properly sized relay can be used to turn the electric heater on/off to ensure solar power is primary source during daylight hours. This allows operation without adjustment to electric heater thermostat.
Operating conditions:
Solar array operating conditions must be less than 250VDC open circuit voltage and greater than 40VDC maximum power point voltage. Maximum device power draw is 2kW.
Maximum operating temperature is 70C (158F).
DC circulatory pump of 10W or less can be directly powered by the device. If a larger pump is required an external power source is needed.
Size of the heating elements are based on the power of the solar array. Maximum power draw from the device is 2kW.
Actual power used by device is based on solar conditions at your location.
device Operation
for domestic hot water
What the animation shows:
PV direct power is used for heating water for storing in a bulk tank. The temperature is set by the user with an on board display interface.
Existing electric hot water tank can be used with the device without modification or alteration to the existing tank.
Inverter is not required for operation, but has the advantage of using PV power once heating is done.
PV power bypassed to inverter once the target temperature is reached. This allows power to be sold to the grid.
What the animation doesn’t show:
Efficiency of device at least 98% under all operating conditions. .
Maximum power point tracking performed by the device to keep solar system at the peak operating point.
Target temperature drops below a user defined threshold, PV power is switched back from inverter (if installed) to heating device.
Activated backup power by the device possible if target temperature is not reached by a user defined time of day. This ensures hot water on cloudy days. External relay may be needed.
device Operation
for space heating
What the animation shows:
PV direct power is used for space heating. An inline circulatory pump is contained in the device and used to provide heat to the target application, whether it is baseboard heat, floor radiant or other hydronic based heating system.
Existing hydronic based heating system can be used with device without modification or alteration.
Secondary heat source, (oil powered boiler shown in demo) can be activated by the device or by normal means from a thermostat.
Inverter is not required for operation, but has the advantage of using PV power once heating is done.
PV power bypassed to inverter once the target temperature is reached. This allows power to be sold to the grid.
What the animation doesn’t show:
Inverter is optional and operates just as before with the domestic hot water application. It is not shown to provide a more focused demonstration of the device operating with the furnace.
Efficiency of device at least 98% under all operating conditions.
Maximum power point tracking performed by the device to keep solar system in peak operating point.
Target temperature drops, PV power is switched back from inverter to heating device.