Gas control method for a hybrid tankless water heater

• US 9,062,895 B2
• Filed: 06/25/2013
• Issued: 06/23/2015
• 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:
  US13/926,750
• Publication Number:
  US 20130284116A1
• Time in Patent Office: 728 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 9/2035 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 reducing natural gas consumption in a hybrid tankless water heating system to avoid a gas over-demand situation, comprising the steps of:

providing a hybrid tankless water heating system comprising a burner having a gas consumption rate and at least one gas pressure sensor adapted to measure available gas pressure supplied to the burner,

measuring the available gas pressure using the gas pressure sensor to detect a potential a gas over-demand situation by comparing the available gas pressure to a predetermined gas over-demand threshold, and

reducing the gas consumption rate of the burner by predetermined levels when a potential gas over-demand situation is detected such that the gas consumption rate of the burner avoids the gas over-demand situation.