Vertical Hot-Water Heat Exchanger for Stratified Storage Tanks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hot-water storage type heating and hot-water supply devices face challenges in achieving efficient heat exchange between stored hot water and supplied hot water, leading to inefficiencies in heating and hot water supply.
Innovation Solution
A hot-water storage type device with a heat pump unit, a hot-water storage tank, and a vertically placed hot-water supplying heat exchanger that utilizes a coil-like pipe with varying pitch and diameter along its length to enhance heat exchange efficiency, along with an electrothermal heater as an auxiliary in case of heat pump failures, and uses carbon dioxide as a refrigerant to improve COP and temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hot-water supplying heat exchanger is placed in the hot-water storage tank, then sanitation is improved, but heat exchange efficiency deteriorates
Solution Approach 1:
The patent applies local quality by creating different functional zones within the hot-water storage tank. The upper portion serves as a hot-water storage region with high temperature, while the lower portion serves as a heating source region with lower temperature. This spatial differentiation allows the heat exchanger to efficiently extract heat from the upper region without disrupting the overall temperature distribution, thereby maintaining both sanitation and heat exchange efficiency
Solution Approach 2:
The patent introduces a vertical dimension to the heat exchange process by positioning the heat exchanger to extend from the upper portion downward into the storage tank. This vertical arrangement allows heat exchange to occur along the height of the tank, utilizing the natural temperature gradient that exists vertically. The heat exchanger receives water from the lower side and discharges it from the upper side, creating a counter-current flow pattern that enhances heat transfer efficiency while preserving the thermal stratification in the storage tank
2Productivity
If hot water is extracted from the hot-water storage tank, then hot water supply is achieved, but temperature distribution in the tank is disturbed
Solution Approach 1:
The patent applies preliminary action by pre-heating the water that will be supplied through the heat exchanger. The heat exchanger is positioned to receive water from the lower portion of the tank and pass it through the upper portion where it picks up heat from the stored hot water. This preliminary heating action ensures that the supplied water reaches the required temperature without needing to extract large volumes of hot water directly from the storage tank, thus preserving the temperature distribution
Solution Approach 2:
The heat exchanger acts as an intermediary between the stored hot water and the water to be supplied. Instead of directly mixing or extracting hot water from the storage tank, the heat exchanger transfers thermal energy from the stored water to the supply water through its walls. This indirect heat transfer mechanism allows hot water supply to be achieved while minimizing disruption to the temperature stratification in the storage tank
3Productivity
If heat exchange power is increased throughout the entire hot-water storage tank, then heat exchange efficiency is improved, but heating power deficiency occurs in the lower region
Solution Approach 1:
The patent applies local quality by concentrating the heat exchange function in the upper portion of the storage tank rather than distributing it uniformly throughout. The heat exchanger is positioned to primarily interact with the hot water in the upper region, where the temperature is highest and heat transfer potential is greatest. This localized heat exchange approach maintains efficient hot water supply while preserving the lower region's thermal energy for heating purposes, avoiding heating power deficiency
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 improves heat exchange efficiency, allows for high-temperature hot water supply, prevents heating power deficiencies, and contributes to global warming countermeasures by using carbon dioxide as a refrigerant, while maintaining a simple construction and effective heat source utilization.
Implementation Method 1
a heat pump unit for heating water
Implementation Method 2
a hot-water supplying heat exchanger including a pipe which is placed in the hot-water storage tank so as to extend roughly entirely in a vertical direction thereof and which receives water from a lower side thereof and discharges hot water from an upper side thereof
Implementation Method 3
a vertically placed hot-water supplying heat exchanger that utilizes a coil-like pipe with varying pitch and diameter along its length to enhance heat exchange efficiency
Data Source
AI summary
A hot-water storage type hot-water supply device includes a heat pump unit (1) for heating water, a hot-water storage tank (21) for storing hot water heated by the heat pump unit (1), and a hot-water supplying heat exchanger (22) placed so as to extend roughly entirely in a vertical direction thereof and which receives water from a lower side thereof and discharges hot water from an upper side thereof.