Heat Pump Hot Water Supply with Dual Refrigerant Cascade Heating
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Solution Overview
Problem
Conventional hot water supply devices associated with heat pumps face challenges in optimizing both hot water supply performance and heating performance simultaneously, often resulting in inefficient heating and potential performance deterioration during switching between heating and cooling modes.
Innovation Solution
The implementation of a dual refrigerant cycle system with a cascade heat exchanger and a hot water supply condenser, where the first refrigerant is used to heat water and the second refrigerant is used for indoor heating, allowing for independent control of refrigerant flow and temperature management to enhance both hot water supply and heating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single refrigerant cycle is used for both hot water supply and heating, then the device complexity is reduced, but the hot water supply performance and heating performance cannot be optimized simultaneously
Solution Approach 1:
The patent divides the single refrigerant cycle into two separate refrigerant cycles: a first refrigerant cycle dedicated to hot water supply and a second refrigerant cycle dedicated to heating. This segmentation allows each cycle to be independently optimized for its specific function, resolving the contradiction between device simplicity and performance optimization.
Solution Approach 2:
The cascade heat exchanger serves multiple functions: it acts as an evaporator for the first refrigerant cycle, a condenser for the second refrigerant cycle, and enables heat transfer between the two refrigerants. This multi-functionality allows the system to achieve both hot water supply and heating optimization without proportionally increasing device complexity.
2Device complexity
If a single refrigerant is used for both hot water supply and heating, then the device complexity is reduced, but the temperature management efficiency decreases
Solution Approach 1:
The patent uses different refrigerants in the first and second cycles that are selected based on their optimal temperature ranges for hot water supply and heating respectively. This allows each refrigerant to operate in its most efficient temperature range, significantly improving temperature management efficiency.
Solution Approach 2:
By changing the refrigerant type parameter in each cycle to match the required temperature characteristics, the system optimizes heat transfer efficiency and temperature control for both hot water supply and heating functions.
3Device complexity
If the heat exchanger is used for both hot water supply and heating, then the device complexity is reduced, but the heat transfer efficiency decreases
Solution Approach 1:
The patent assigns dedicated heat exchangers to each refrigerant cycle: a hot water supply heat exchanger for the first cycle and a heating heat exchanger for the second cycle. This dedicated configuration maximizes heat transfer efficiency by eliminating the performance losses that would occur from sharing a single heat exchanger.
Solution Approach 2:
The cascade heat exchanger is designed to function as both an evaporator for the first refrigerant and a condenser for the second refrigerant simultaneously, enabling efficient heat transfer between the two cycles while maintaining optimal heat transfer surfaces for each function.
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 approach improves hot water supply performance by utilizing the highest temperature refrigerant for water heating and enhances heating performance by using a two-stage refrigerant cycle, ensuring continuous operation regardless of heating or cooling modes, and reduces the refrigerant amount required for hot water supply.
Implementation Method 1
a first refrigerant circulation part in which a first refrigerant cycle is performed, a hot water supply part which supplies hot water using the first refrigerant
Implementation Method 2
a second refrigerant circulation part in which a second refrigerant cycle is performed, and a heating part which heats an indoor space using the second refrigerant
Implementation Method 3
a cascade heat exchanger exchanging heat between the first refrigerant and the second refrigerant
Data Source
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AI summary
Provided is a hot water supply device associated with a heat pump. In the hot water supply device, hot water supply is performed using a high-temperature refrigerant discharged from a compressor, and simultaneously, indoor heating is performed using a two-stage refrigerant cycle. Thus, hot water supply performance and heating performance are may be further improved.