Water Stratification Drum With Perforated Plates for Thermal Layering
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Solution Overview
Problem
Existing water heaters face inefficiencies due to rapid mixing of cold water with hot water, leading to premature temperature drops and increased energy consumption, as well as challenges in effectively utilizing cold water for flue gas cooling and heating in condensing systems.
Innovation Solution
A water stratification drum is installed in the lower portion of the tank, featuring perforated plates to slow the mixing of cold water with hot water, allowing it to be preheated near the combustion chamber and then reused in an external heat exchange with flue gases, thereby conserving energy and optimizing temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cold water is introduced into the water holding tank, then the tank can be refilled, but the cold water immediately mixes with hot water causing temperature drop and triggering premature heating
Solution Approach 1:
The tank interior is segmented into distinct thermal zones using a baffle structure. The baffle creates a cold water storage zone at the bottom and a hot water zone above, with a controlled mixing zone in between. This segmentation prevents immediate mixing of cold and hot water, maintaining temperature stratification and reducing energy consumption.
Solution Approach 2:
A baffle structure acts as an intermediary element between the cold water inlet and the hot water storage zone. The baffle controls the interface between cold and hot water, allowing gradual mixing only in the designated mixing zone while protecting the main hot water storage area from direct contact with cold water.
2Temperature
If external heat exchange devices are used to cool flue gases, then flue gas temperature can be reduced, but the device complexity and size of the water heater increase
Solution Approach 1:
The flue gas heat exchange function is merged with the existing tank structure. The baffle and tank walls serve dual purposes: maintaining water stratification and acting as heat exchange surfaces for cooling flue gases. This integration eliminates the need for separate external heat exchange devices, reducing system complexity while achieving flue gas cooling.
Solution Approach 2:
The baffle structure is designed to perform multiple functions simultaneously: it maintains thermal stratification in the water tank, provides a controlled mixing zone, and serves as a heat exchange surface for cooling flue gases. This multi-functionality reduces the overall number of components needed in the system.
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 solution effectively retards the mixing of cold and hot water, reducing energy consumption and enhancing the efficiency of flue heat recovery by preheating the cold water before it mixes with the hot water, while also using the heated water to cool flue gases, resulting in energy savings and cost reductions.
Implementation Method 1
cooler water is admitted between the plates and released in a restraining manner in a lower portion of the tank to retard its admixture with water in the other portions of the tank
Implementation Method 2
direct it in the area of the combustion chamber hot surface region to preheat the cooler water at the bottom of the tank
Implementation Method 3
harness the cooler water to create a cooler water strata to retard its mixing with the hotter water in the tank
Implementation Method 4
water from this strata is pumped through an external heat exchange device in communication with the hot flue gases from the central flue to extract heat therefrom
Data Source
AI summary
A water stratification drum for use in an electric and condensing water heater is disposed in a lower portion of the water holding tank and across the circumferential side wall of the tank. The water stratification drum has a pair of plates held spaced-apart by support members which extend between the pair of plates to maintain the plates in substantially parallel relationship. A cold water zone is defined between the plates and cool domestic water is introduced in the tank between the plates. The plates are flat disc plates formed on non-corrosive material and water there between is diffused in a controlled manner to other regions of the tank through at least one of the plates being perforated. The diffusion of the water prevents premature actuation of the heat source by not causing an abrupt change in the temperature of the hot water in the tank.