Modulation systems and methods for instantaneous hot water applications

A heater system configured to modulate a heating input rate, the heater system comprising:

• a first heat exchanger configured to heat water;
• a second heat exchanger configured to receive the heated water from the first heat exchanger and deliver water to a domestic hot water outlet;
• a plurality of temperature sensors for sensing a plurality of water temperatures at one or more locations within the heater system;
• a flow detector designed to measure a flow rate at the domestic hot water outlet;
• a control system configured to:
• determine an expected flow demand for the heated water based on an expected appliance use;
• determine an initial heating input rate based on the expected flow demand;
• monitor the plurality of water temperatures and the flow rate;
• determine a target heating input rate based on at least one of the plurality of sensed water temperatures or the flow rate at the domestic hot water outlet;
• modulate the initial heating input rate to the target heating input rate when the target heating input rate is different than the initial heating input rate;
• detect a change in at least one of the sensed temperatures or the flow rate;
• and
• modulate the target heating input rate proportionally with the detected change.

A heater system configured to modulate a heating input rate, the heater system comprising:

• a heat exchanger designed to heat water and deliver the heated water to a domestic hot water outlet;
• a flow sensor designed to measure a flow rate of the heated water at the domestic hot water outlet;
• and
• a control system designed to:
• determine an expected flow demand for the heated water based on an expected appliance use;
• determine an initial heating input rate based on the expected flow demand;
• monitor the measured flow rate;
• detect a change in the measured flow rate;
• determine a target heating input rate based on the detected change in the measured flow rate;
• and
• modulate the initial heating input rate to the target heating input rate when the target heating input rate is greater than the initial heating input rate.