Hybrid Tankless Water Heater Buffer Control for Stable Output Temperature
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Solution Overview
Problem
Existing tankless water heaters face challenges in maintaining a constant water output temperature during rapid shifts in demand, leading to temperature fluctuations, delays, and safety hazards, and are often expensive and inefficient due to their design and operation.
Innovation Solution
A hybrid tankless water heater system with a thermally insulated mixing buffer tank, secondary heating element, differential pressure switch, and recirculating system to maintain desired temperatures, reduce delays, and prevent temperature fluctuations, along with advanced control methods for fine temperature adjustment and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a tankless water heater is used to reduce space and energy consumption, then space requirement and energy efficiency are improved, but temperature stability during rapid demand shifts deteriorates
Solution Approach 1:
The system pre-heats water in a storage tank before demand occurs, and pre-activates the heating element when demand is detected. This preliminary action ensures that hot water is immediately available when needed, eliminating the temperature instability that would otherwise occur during rapid demand shifts.
Solution Approach 2:
The system divides the water heating function into two separate components: a storage tank that maintains a reservoir of pre-heated water, and a tankless heating element that activates on demand. This segmentation allows the system to combine the temperature stability of stored hot water with the energy efficiency of on-demand heating.
2Use of energy by stationary object
If a tankless water heater operates without a storage tank to improve energy efficiency, then energy consumption is reduced, but response time to deliver hot water deteriorates
Solution Approach 1:
The system maintains a storage tank with pre-heated water ready for immediate delivery. When hot water demand is detected, the system can immediately draw from this pre-heated reservoir, eliminating the delay that would otherwise occur while waiting for the tankless heater to heat water.
Solution Approach 2:
The system continuously maintains a supply of hot water in the storage tank, ensuring that hot water is always available for immediate delivery. This continuous preparation eliminates response time delays while the tankless heating element supplements the system only when the stored hot water is depleted.
3Productivity
If the water heater prioritizes flow rate to meet water demand, then water delivery capability is improved, but temperature control deteriorates
Solution Approach 1:
The system introduces a storage tank as an intermediary between the water source and the point of use. This tank acts as a buffer that decouples the high-flow demand from the heating process, allowing the tankless heating element to operate at optimal temperatures while still meeting high flow rate requirements.
Solution Approach 2:
The system separates the water storage and heating functions from the temperature control function. The storage tank handles high-flow delivery requirements, while a separate mixing mechanism controls the final temperature by blending heated water with cooler water, allowing both high flow rate and precise temperature control to be achieved simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively minimizes temperature variations, reduces delays in achieving desired temperatures, eliminates cold sandwich effects and dead zones, and enhances energy efficiency while being more economical and user-friendly.
Implementation Method 1
a heat exchanger located within the primary heating subsystem
Implementation Method 2
a thermally insulated mixing buffer tank disposed downstream from the heat exchanger
Implementation Method 3
There is further provided a secondary heating element to supply supplemental heat
Data Source
AI summary
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.