Heat Exchanger Cooling Control to Prevent Hot Water Scale
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Solution Overview
Problem
Existing hot water supply apparatuses face challenges in effectively preventing scale formation in heat exchangers, leading to reduced heat transfer efficiency and increased maintenance costs due to the limitations of traditional anti-scale methods.
Innovation Solution
A hot water supply apparatus that incorporates a heat source device with a controller capable of performing both heating and cooling operations, using a vapor compression refrigeration cycle to quickly lower the temperature of the water in the heat exchanger, thereby preventing scale formation and maintaining heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional anti-scale operation is performed by replacing water in the water circuit with low-temperature water from the tank, then scale formation is blocked, but the temperature of water in the heat exchanger cannot be rapidly lowered and heat transfer efficiency decreases
Solution Approach 1:
Instead of using cold water from the tank to cool the heat exchanger (traditional method), the invention uses hot water from the heat exchanger to heat the tank water. This reverse heat transfer approach achieves scale prevention by rapidly lowering heat exchanger water temperature while simultaneously preheating the tank water, thereby maintaining overall system efficiency and avoiding the temperature loss associated with traditional cooling methods
Solution Approach 2:
The invention changes the temperature parameter dynamics by implementing a rapid cooling phase followed by a heating phase. The controller temporarily reverses the normal heat transfer direction to achieve rapid temperature reduction in the heat exchanger for scale prevention, then restores normal operation to maintain operational temperature. This dynamic parameter manipulation allows both scale prevention and heat transfer efficiency to be maintained
2Reliability
If the heat source device continuously heats water to prevent scale formation, then heat transfer efficiency is maintained, but energy consumption increases
Solution Approach 1:
The invention implements periodic anti-scale operations rather than continuous heating. The controller periodically initiates rapid cooling cycles using the reverse heat transfer method, followed by normal heating operation. This periodic action maintains scale prevention effectiveness while significantly reducing overall energy consumption compared to continuous heating, as the system only needs to restore temperature after periodic cooling events rather than maintaining elevated temperature constantly
Solution Approach 2:
The system uses its own hot water from the heat exchanger as the heating source for the tank water during anti-scale operations. This self-service approach eliminates the need for additional external energy input during the heating phase of the anti-scale cycle, as the heat extracted from the heat exchanger water during cooling is reused to heat the tank water, creating an energy-efficient closed loop
3Productivity
If rapid cooling is performed to prevent scale formation, then scale removal efficiency is improved, but the complexity of the control system increases
Solution Approach 1:
The invention merges the cooling and heating functions into a single integrated reverse heat transfer operation. The same heat exchanger and water circulation system used for normal heating are repurposed for rapid cooling by simply reversing the heat transfer direction. This merging approach achieves rapid scale removal through efficient heat transfer while avoiding the need for separate cooling systems or complex control mechanisms, as the existing system components perform dual functions
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 apparatus effectively prevents scale formation by rapidly cooling the water in the heat exchanger, maintaining heat transfer efficiency and reducing maintenance costs through intelligent temperature control and scale removal mechanisms.
Implementation Method 1
A hot water supply apparatus that incorporates a heat source device with a controller capable of performing both heating and cooling operations, using a vapor compression refrigeration cycle to quickly lower the temperature of the water in the heat exchanger
Implementation Method 2
a heat exchanger (25) having a first channel (25a) connected to the water circuit (50); and a controller (80) configured to control the heat source device (20) and the water circuit (50), wherein the controller (80) is configured to perform: a first operation in which the heat source device (20) directly or indirectly heats the water in the first channel (25a) of the heat exchanger (25)
Implementation Method 3
a second operation in which the heat source device (20) directly or indirectly cools the water in the first channel (25a) of the heat exchanger (25) after the first operation ends
Implementation Method 4
The apparatus effectively prevents scale formation by rapidly cooling the water in the heat exchanger, maintaining heat transfer efficiency
Data Source
AI summary
A controller performs a first operation in which a heat source device directly or indirectly heats water in a first channel of a heat exchanger and a second operation in which the heat source device directly or indirectly cools the water in the first channel of the heat exchanger after the first operation ends.