CONTROL SYSTEM METHODS FOR NETWORKED WATER HEATERS

• US 20120191259A1
• Filed: 03/30/2012
• Published: 07/26/2012
• Est. Priority Date: 02/03/2009
• Status: Active Grant

• Current Assignee: Intellihot Inc.
• Original Assignee: Intellihot Green Technologies, Inc.
• Inventors: Deivasigamani, Sridhar, Akasam, Sivaprasad
• Granted Patent: US 8,271,143 B2
• Time in Patent Office: Days
• US Class Current: 700/282
• 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

Disclosed is a control system for controlling a plurality of fluidly and operably connected water heaters to meet a hot water demand such that overall efficiency is maximized and usage disparity between water heaters is minimized. There is further disclosed a method for detecting a small system demand in said network by adjusting the setting of each flow limiting valve of each water heater. There is still further disclosed a method for enabling seamless addition or removal of a heater in service and heating load distribution to water heaters.

Claims

1. A method for controlling a plurality of fluidly and operably connected water heaters in a network to meet a system demand, comprising steps of:

providing a value corresponding to relative remaining life of each said water heater, a value corresponding to a minimum output of each said water heater, a flow limiting valve for each said water heater and a pump for each said water heater;

obtaining a number of participating water heaters required to service said system demand by dividing said system demand by said value corresponding to minimum output;

obtaining an average heating load by dividing said system demand by said number of participating water heaters in said network;

selecting participating water heaters by identifying said number of participating water heaters having the longest relative remaining life; and

setting and activating each of said selected participating water heaters at said average heating load to provide a total load meeting said system demand.

2. The method for controlling a plurality of fluidly and operably connected water heaters in a network to meet a system demand of claim 1, wherein said step of obtaining a number of participating water heaters comprises dividing said system demand by said value corresponding to minimum output.

3. The method for controlling a plurality of fluidly and operably connected water heaters in a network to meet a system demand of claim 1, wherein said step of obtaining a number of participating water heaters comprises estimating the total cost of operating different quantities of water heaters of said plurality of water heaters where the heating load is substantially equally distributed over said different quantities of water heaters of said plurality of water heaters and selecting the number of participating water heaters that yields a lowest cost.

4. The method for controlling a plurality of fluidly and operably connected water heaters in a network to meet a system demand of claim 1, wherein said value corresponding to relative remaining life comprises normalized factors of expended energy, thermal cycle count, blower speed, flow rate and outlet-inlet water temperature difference of a water heater.

5. The method for controlling a plurality of fluidly and operably connected water heaters in a network to meet a system demand of claim 1, wherein each of said plurality of water heaters has a controller, wherein distribution of a heating load to each of said plurality of water heaters is determined by its controller.

6. The method for controlling a plurality of fluidly and operably connected water heaters in a network to meet a system demand of claim 1, wherein each of said water heaters has a controller, wherein the heating load corresponds to a flow which is achieved by controlling concurrently said flow limiting valve of each water heater and said pump of each water heater.

7. A method for detecting a small flow in a plurality of fluidly and operably connected water heaters in a network, each of said plurality of water heaters has a flow limiting valve having a flow range of from zero to a non-zero value, a flow sensor having a minimum detectable flow, a value corresponding to a predetermined potential system demand, a value corresponding to the maximum output of a water heater in said network, comprising steps of:

obtaining a number of participating water heaters required to service said predetermined potential system demand by dividing said value corresponding to said predetermined potential system demand by said value corresponding to the maximum output of a water heater in said network;

obtaining an average flow limiting valve setting by dividing said predetermined potential system demand by said number of participating water heaters in said network;

selecting participating water heaters by identifying said number of participating water heaters having the longest relative remaining life; and

setting and activating said flow limiting valve of each of said selected participating water heaters at said average flow limiting valve setting.