Intermediate Heat Exchanger Cycle for Stable Heat Pump Heating
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Solution Overview
Problem
Conventional air-conditioning apparatuses with a vapor compression cycle and a liquid pump cycle are unable to perform heating operations due to gas flow into the pump, leading to unstable drive and potential breakdown, and cannot efficiently switch between cooling and heating modes.
Innovation Solution
An air-conditioning apparatus with an intermediate heat exchanger that switches heat transfer, a use-side cycle circuit including a pump that handles liquid heat medium, and pressure-reducing devices to ensure stable phase change and circulation, allowing for efficient heating and cooling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid pump cycle is used for the secondary-side cycle, then cooling operation can be achieved, but gas flows into the pump causing unstable drive and breakdown
Solution Approach 1:
An intermediate heat exchanger is introduced between the primary-side cycle and secondary-side cycle. This intermediary device enables heat transfer between the two cycles without direct mixing of refrigerants, preventing gas from entering the pump while maintaining efficient heat exchange. The intermediate heat exchanger acts as a buffer that separates the vapor compression cycle (primary) from the liquid pump cycle (secondary), allowing independent operation of each cycle.
Solution Approach 2:
The system is divided into separate primary-side and secondary-side cycles with distinct functions. The primary-side cycle handles refrigerant compression and phase change, while the secondary-side cycle handles liquid pump circulation and heat exchange with air. This segmentation allows each subsystem to operate optimally without interference, preventing gas ingress into the pump while maintaining cooling efficiency.
2Adaptability or versatility
If the refrigerant in the primary-side cycle heats the refrigerant in the secondary-side cycle, then heating operation should be achieved, but the system cannot perform heating operation
Solution Approach 1:
The system incorporates dynamic flow control valves that can redirect refrigerant flow between different pathways. During heating operation, these valves dynamically switch the flow direction to enable the primary-side refrigerant to heat the secondary-side refrigerant. This dynamic adaptability allows the system to transition between cooling and heating modes while maintaining stable operation through controlled fluid distribution.
3Productivity
If a vapor compression cycle and liquid pump cycle are combined, then cooling operation is achieved, but the system lacks heating capability
Solution Approach 1:
The dual-cycle system is designed with universal heat exchangers that can function in both heating and cooling modes. By configuring the intermediate heat exchanger and use-side heat exchanger with reversible heat transfer capabilities, the system achieves multi-functionality. The same hardware infrastructure supports both cooling (removing indoor heat) and heating (transferring heat into the room) operations, eliminating the need for separate dedicated systems.
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
Enables stable cooling and heating operations by preventing gaseous state heat medium from entering the pump, enhancing system efficiency and preventing breakdowns, while allowing for efficient phase change and heat transfer in the air-conditioning target space.
Implementation Method 1
an intermediate heat exchanger that exchanges heat between a heat source-side heat medium and a use-side heat medium
Implementation Method 2
causes the use-side heat medium to undergo a phase change
Implementation Method 3
a use-side heat exchanger that heats or cools air in an air-conditioning target space due to heat exchange
Data Source
AI summary
An air-conditioning apparatus includes: a heat source-side system having an intermediate heat exchanger that causes heat exchange to be performed between a heat source-side heat medium and a use-side heat medium, causes the heat source-side heat medium to receive or transfer heat, and causes the use-side heat medium to undergo a phase change; and a use-side cycle circuit formed of pipes connecting, to one another, the intermediate heat exchanger, a pump that sucks and delivers the use-side heat medium in a liquid state, a use-side heat exchanger that heats or cools air in an air-conditioning target space due to heat exchange causing a change in phase of the use-side heat medium, and a pressure-reducing device that reduces a pressure of the use-side heat medium that passes through the use-side heat exchanger, the use-side cycle circuit causing the use-side heat medium to circulate through the use-side cycle circuit.