Heat Pump Hot-Water Tank Circulation for Scale Prevention
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Solution Overview
Problem
Heat pump type hot water supply devices face issues with scale deposition in water tanks and circulation pipes due to high water temperatures, particularly with well water of high hardness, leading to reduced performance and increased size of heat exchangers.
Innovation Solution
The device incorporates a water supply system with multiple paths, including a direct path and a path through a water quality adjusting unit, which improves water quality to prevent scale formation, using flow rate control and water quality adjusting units like softening, acidity adjustment, and crystal refinement to manage calcium deposition, and monitors scale deposition to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water is heated to high temperature (90°C) in the water tank, then hot water supply performance is improved, but scale deposition increases significantly
Solution Approach 1:
The patent applies preliminary action by introducing a water quality adjusting unit that treats water before it enters the water tank. This unit performs scale prevention treatment in advance, preventing scale formation before the water is heated to high temperatures, thus resolving the contradiction between achieving high temperature hot water supply and preventing scale deposition
Solution Approach 2:
The patent uses an intermediary substance (scale prevention agent) that is introduced into the water before heating. This intermediary prevents scale formation during the heating process, allowing high temperature operation without the harmful scale deposition that would otherwise occur
2Quantity of substance
If a large amount of water is stored in the water tank and heated, then hot water supply capacity is improved, but scale deposition in the water tank and circulation pipe increases
Solution Approach 1:
The water quality adjusting unit performs scale prevention treatment on all water before it is stored in the water tank. This preliminary treatment ensures that even when large amounts of water are stored and heated, scale deposition is prevented throughout the entire water volume and circulation system
3Quantity of substance
If well water of high hardness is used, then water availability is improved, but scale deposition increases due to high calcium content
Solution Approach 1:
The patent introduces a scale prevention agent as an intermediary substance that reacts with the calcium in hard well water. This agent binds to the calcium ions, preventing them from forming scale deposits on heat exchanger surfaces and pipe walls, thus allowing the use of hard well water without scale problems
Solution Approach 2:
The water quality adjusting unit changes the chemical parameters of the water by adding scale prevention agents. This alters the water chemistry to prevent calcium precipitation, transforming hard water into scale-free water that can be safely heated and circulated
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
This solution effectively reduces scale deposition, improves heat exchange performance, and reduces the size and cost of the heat exchanger, allowing for efficient hot water supply at higher temperatures without the need for large tanks.
Implementation Method 1
The heat radiating heat exchanger 2 condenses the refrigerant of high temperature and high pressure that is compressed by the compressor 1 to release heat from the refrigerant
Implementation Method 2
The heat absorbing heat exchanger 10 is arranged on the water circulation pipe 9 and connected to the heat radiating heat exchanger (refrigerant side heat exchanger) 2 of the heat pump unit A on the heat source side so as to absorb heat
Implementation Method 3
The expansion valve 3 depressurizes the high-pressure refrigerant that is condensed by the heat radiating heat exchanger 2
Implementation Method 4
The air heat exchanger 4 evaporates the refrigerant that is depressurized by the expansion valve 3 to absorb heat from air that is supplied via a fan 5
Data Source
AI summary
A heat pump type hot water supply device is provided with a heat source side heat pump unit having a heat radiating heat exchanger that condenses refrigerant to radiate heat from the refrigerant. The hot water supply device is provided with a water tank that stores water, a water supply pipe that supplies water to the water tank from the outside, a water circulation pipe that is extended in a bypassing manner and circulates the water in the water tank from a bottom section to an upper section, a heat absorbing heat exchanger that is arranged on the water circulation pipe and connected to the heat radiating heat exchanger of the heat source side heat pump unit so as to absorb heat, and a hot water supply unit that comprises a hot water supply pipe that supplies warm water in the upper section of the water tank to the outside.