Apparatus and control method for a hybrid tankless water heater

• US 9,234,679 B2
• Filed: 06/25/2013
• Issued: 01/12/2016
• Est. Priority Date: 02/03/2009
• Status: Active Grant

• Current Assignee: Intellihot Inc.
• Original Assignee: Intellihot Green Technologies, Inc.
• Inventors: Deivasigamani, Sridhar, Akasam, Sivaprasad
• Primary Examiner(s): CAMPBELL, THOR S
• Application Number:
  US13/926,608
• Publication Number:
  US 20130284117A1
• Time in Patent Office: 931 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: F24D 17/0026 with conventional heating means F24D17/0036 takes precedence
• CPC Class Codes: F24D 17/0031 with accumulation of the heated water
• CPC Class Codes: F24D 17/0073 Arrangements for preventing the occurrence or proliferation of microorganisms in the water
• CPC Class Codes: F24D 17/0078 Recirculation systems
• CPC Class Codes: F24D 17/0089 Additional heating means, e.g. electric heated buffer tanks or electric continuous flow heaters, located close to the consumer, e.g. directly before the water taps in bathrooms, in domestic hot water lines
• CPC Class Codes: F24H 1/124 using fluid fuel
• CPC Class Codes: F24H 1/202 with resistances
• CPC Class Codes: F24H 1/52 incorporating heat exchangers for domestic water F24H1/50 takes precedence
• CPC Class Codes: F24H 15/144 Measuring or calculating energy consumption
• CPC Class Codes: F24H 15/156 Reducing the quantity of energy consumed; Increasing efficiency
• CPC Class Codes: F24H 15/238 Flow rate
• CPC Class Codes: F24H 15/31 of valves having only one inlet port and one outlet port, e.g. flow rate regulating valves
• CPC Class Codes: F24H 15/36 of burners
• CPC Class Codes: F24H 9/2021 Storage heaters
• CPC Class Codes: F24H 9/2035 using fluid fuel
• CPC Class Codes: G05D 23/1927 using a plurality of sensors G05D23/1902, G05D23/1917, and G05D23/1919 take precedence
• CPC Class Codes: G05D 23/1931 to control the temperature of one space
• CPC Class Codes: Y10T 137/1244 With freeze waste
• CPC Class Codes: Y10T 137/6579 Circulating fluid in heat exchange relationship
• CPC Class Codes: Y10T 137/85978 With pump
• CPC Class Codes: Y10T 137/86389 : Programmer or timer

Abstract

An on demand tankless water heater system that is capable of quickly delivering water within a desired temperature range. The tankless water heater provides a hybrid heating method that contains a primary heating system and a secondary heating system disposed in a buffer tank that cooperate to facilitate control of output water temperature during water usage. A pressure differential switch detects low flow demand and allows the secondary heating system to provide immediate heating to the water. This secondary heating system provides a faster temperature response and fine tuning of output water temperature.

Claims

1. A method for controlling thermal spikes caused by overheating in a water supply of a water supply system, the method comprising the steps of:

providing a tankless water heater having a blower, a heat exchanger and a burner, wherein the burner has a thermal output providing a means for heating the water supply,

providing a means for detecting a decrease in a flow rate of the water supply, measuring the flow rate of the water supply to detect a decrease in the flow rate, and

activating the blower when a decrease in the flow rate of the water supply has been detected, thereby dissipating excess heat from the heat exchanger to the environment.

2. The method for controlling thermal spikes of claim 1, wherein the method further comprises the step of reducing thermal output of the burner, thereby reducing the thermal energy delivered to the water supply.

3. A method for controlling thermal spikes caused by overheating in a water supply of a water supply system, the method comprising the steps of:

providing a tankless water heater having a blower, a burner, a heat exchanger and an internal recirculation system,

providing a means for detecting a decrease in a flow rate of the water supply, measuring the flow rate of the water supply to detect a decrease in the flow rate, and

activating the internal recirculation system when a decrease in the flow rate has been detected, thereby distributing excess heat contained in the heat exchanger over a volume of water contained in the internal recirculation system to cool the water supply.

4. The method for controlling thermal spikes of claim 3, wherein the method further comprises the step of activating the blower, thereby accelerating the dissipation of thermal energy of the water supply.

5. The method for controlling thermal spikes of claim 3, wherein the method further comprises the step of reducing thermal output of the burner, thereby reducing the thermal energy delivered to the water supply.

6. A method for controlling thermal spikes caused by overheating in a water supply of a water supply system, the method comprising the steps of:

providing a tankless water heater having a blower, a heat exchanger, a burner and an external recirculation system wherein the burner has a thermal output providing a means for heating the water supply,

providing a means for detecting a decrease in a flow rate of the water supply, measuring the flow rate of the water supply to detect a decrease in the flow rate, and

activating the external recirculation system when a decrease in the flow rate of the water supply has been detected, thereby dissipating excess heat from the heat exchanger to the environment.