System, apparatus and method for efficient use of solar photovoltaic energy

A controller for a variable energy source system, the controller comprising:

• one or more processors;
• and
• memory having instructions stored thereon that, when executed by the one or more processors, cause the controller to:
• receive temperature information from a temperature sensor, the temperature information being indicative of a temperature of fluid in a tank of a water heater;
• receive current flow direction information indicative of a current inflow from a utility grid or current flow to the utility grid;
• and
• control delivery of energy from a variable energy source to the water heater by:
• in response to determining that the temperature of the fluid is less than a threshold temperature and the current flow direction information is indicative of current outflow to the utility grid, outputting instructions for modulating a flow of energy from the variable energy source to at least a first heating element of the water heater;
• and
• in response to determining that (i) the temperature of the fluid is less than the threshold temperature, (ii) the current flow direction information is indicative of current outflow to the utility grid, and (iii) the first heating element has reached a maximum power output, outputting instructions for operating a second heating element of the water heater and further modulating the flow of energy from the variable energy source to at least the first heating element.

A method for controlling energy in a variable energy source system, the method comprising:

• receiving temperature information from a temperature sensor, the temperature information being indicative of a temperature of fluid in a tank of a water heater;
• receiving current flow direction information indicative of a current inflow from a utility grid or current flow to the utility grid;
• and
• controlling delivery of energy from a variable energy source to the water heater by:
• in response to determining that the temperature of the fluid is less than a threshold temperature and the current flow direction information is indicative of current outflow to the utility grid, outputting instructions for modulating a flow of energy from the variable energy source to at least a first heating element of the water heater;
• and
• in response to determining that (i) the temperature of the fluid is less than the threshold temperature, (ii) the current flow direction information is indicative of current outflow to the utility grid, and (iii) the first heating element has reached a maximum power output, outputting instructions for operating a second heating element of the water heater and further modulating the flow of energy from the variable energy source to at least the first heating element.