Heating element assembly for electric tankless liquid heater

#A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the file or records of the Patent and Trademark Office, but otherwise reserves all copyright rights whatsoever.

#This disclosure generally relates to systems and methods for heating liquids. In particular, this disclosure relates to a heating element assembly for electric liquid heating systems.

#The most common approach for providing hot water in both domestic and commercial settings involves the use of large tanks for the storage of hot water. Although such heated tank systems can provide hot water at a relatively high flow rate, they are inherently energy inefficient because the water in the tank is continually reheated even when water is not being used on a regular basis. Another approach to providing hot water involves the use of a tankless water heater system that heats water only when hot water is being used. Such tankless water heater systems, also referred to as demand water heater systems, can often provide a more energy efficient means of heating water than storage systems using the same type of heating (e.g., gas, electric, etc.).

#FIG. 1 is an assembly drawing illustrating various embodiments of an electric tankless liquid heater system;

#FIGS. 2 and 3 are detailed views of one embodiment of an inlet manifold;

#FIGS. 4A-4D are various views of one embodiment of a liquid heater for an electric tankless liquid heater system; where FIG. 4A is a sectional view, FIG. 4B a side view, FIG. 4C a switching unit side, side view, and FIG. 4D a proximate end, end view of the liquid heater;

#This disclosure provides, in various aspects, systems for heating a liquid, such as, for example, water. The systems may be configured to deliver, in various embodiments, hot liquids, and in particular hot water of a particular temperature and/or temperature range, at a certain flow rate and/or under various demand characteristics. Accordingly, in various embodiments, the disclosure describes systems for provision of hot water to multiple water fixtures, and in particular, for example, to a group of automatic fixtures with frequent and rapid changes in hot water demand. Examples of such groups of fixtures and situations include, but are not limited to, multi-station wash basins in high traffic facilities (e.g., industrial washrooms at the end-of-shifts, washrooms in sports stadiums, etc.) and showers facilities with multiple concurrent users (e.g., locker room facilities, dorm facilities, mass decontamination situations, etc.).

#Referring to FIG. 1, in various embodiments, a tankless water heater system 100 comprises a plurality of liquid heaters 102 each having a liquid inlet 104 and a liquid outlet 106. The liquid inlets 104 of the liquid heaters 102 may be connected in a parallel flow relationship by an inlet manifold 108, which in turn can be connected to a source of liquid 110 to be heated, such as, e.g., a cold water line, by an inlet manifold connection fitting 112. The liquid outlets 106 of the liquid heaters 102 may each be connected to a separate outlet conduit 114, 115, 116. Each outlet conduit can be, for example, connected to a separate fixture for the supply of hot liquid. In other embodiments, the liquid outlets 106 of the liquid heaters 102 may be connected to an outlet manifold. For example and in one embodiment, the liquid outlets 106 may be connected in a parallel flow relationship by an outlet manifold, which in turn may be connected to a hot liquid supply line by an outlet manifold connection fitting. In yet other embodiments, a tankless water heater system 100 may comprise a single liquid heater 102 connected to a source of liquid 110 to be heated.

#In various embodiments, each liquid heater may include one or more electrical resistance heating elements. Electrical power to the electrical resistance heating elements may pass through a switching unit 120 and, in some embodiments, a separate circuit relay (also referred to as a contactor) 122 for each liquid heater. A controller 124, in various embodiments, mounted on the liquid heater, regulates the operation of a switching unit 120 and hence the current flow to one or more electrical resistance heaters of a liquid heater. The circuit relays 122, and therethrough one or more switching units, may be connected to a source of electrical power through taps in terminal blocks 126, which are connected to a source of electrical power (e.g., line voltage). In certain embodiments, use is also made of a ground terminal block. In some embodiments, a separate circuit relay 122 is used to energize or “arm” each switching unit and each switching unit regulates electrical current flow to the one or more electrical resistance heating elements connected thereto.