Dual-Loop Air Conditioning With Anti-Freezing Heat Medium Control
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Solution Overview
Problem
Conventional air-conditioning apparatuses face issues with refrigerant leakage indoors, high energy consumption due to water circulation, and the risk of water freezing in chillers, which affect energy efficiency and safety.
Innovation Solution
The air-conditioning apparatus employs an intermediate heat exchanger to separate the refrigerant and heat medium circulation, with a refrigeration cycle and heat medium circulation circuit connected via separate piping, and includes an anti-freezing operation mode to prevent heat medium freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant such as HFC is transferred into the indoor unit, then cooling or heating function is achieved, but refrigerant leakage deteriorates the indoor environment
Solution Approach 1:
The patent introduces a heat medium (water or anti-freeze liquid) as an intermediary substance to transfer thermal energy from the outdoor heat source to the indoor heat exchanger. This heat medium circulates through separate piping independent of the refrigerant system, enabling indoor cooling/heating without introducing refrigerant into the indoor environment, thereby eliminating refrigerant leakage hazards indoors.
2Loss of energy
If water is transferred to the indoor unit for heat exchange, then heat transfer function is achieved, but carrying power of water becomes extremely large and non-energy saving
Solution Approach 1:
The patent divides the thermal energy transfer system into two independent circulation loops: a refrigerant loop operating outdoors and a heat medium loop operating indoors. The heat medium circulation is segmented into separate piping with dedicated pumps for outdoor and indoor units, allowing independent optimization of each loop's flow rate and pressure, thereby reducing the carrying power requirement compared to a single integrated water circulation system.
3Reliability
If water is used as heat medium in piping, then heat transfer efficiency is improved, but water may freeze in cold conditions
Solution Approach 1:
The patent modifies the physical-chemical parameters of the heat medium by adding anti-freeze agents (such as ethylene glycol or propylene glycol) to water, creating an anti-freeze liquid with lowered freezing point. This parameter change enables the heat medium to maintain liquid state and continue circulating in cold environmental conditions, preventing freezing damage to the piping system while preserving heat transfer functionality.
4Adaptability or versatility
If refrigerant circulation system is used, then cooling and heating functions are achieved, but the system complexity increases with separate refrigerant handling
Solution Approach 1:
The patent merges the refrigerant circulation system and heat medium circulation system into a coordinated dual-loop architecture where the outdoor heat source unit handles refrigerant compression and heat exchange, while the indoor unit handles heat medium circulation and final heat transfer to indoor air. This merging allows both cooling and heating functions to be achieved through a single integrated system that shares common components like the compressor and heat exchangers, reducing overall system complexity compared to separate 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
This design prevents refrigerant leakage, reduces water circulation power, and enhances energy efficiency and reliability by eliminating the need for refrigerant in indoor units and providing an anti-freezing mechanism.
Implementation Method 1
at least one intermediate heat exchanger that exchanges heat between a refrigerant and a heat medium that is different from the refrigerant
Implementation Method 2
a heat medium circulation circuit in which a heat medium side flow path of the intermediate heat exchanger, a pump, and a use side heat exchanger are connected via piping through which the heat medium flows
Implementation Method 3
a refrigeration cycle in which a compressor, a heat source side heat exchanger, at least one expansion valve, and a refrigerant side flow path of the intermediate heat exchanger are connected via piping through which the refrigerant flows
Implementation Method 4
at least one expansion valve, and a refrigerant side flow path of the intermediate heat exchanger are connected via piping
Data Source
AI summary
In an air-conditioning apparatus, a heat source side heat exchanger, intermediate heat exchangers, and use side heat exchangers are formed in separate bodies respectively and adapted to be disposed at separate locations one another. In a heat medium circulation circuit where the intermediate heat exchanger and the use side heat exchanger are connected, temperature sensors are installed. An anti-freezing operation mode is provided in which, when the detection temperatures of the temperature sensors become equal to or lower than a set temperature Ts while a compressor or pumps are stopped, the heat medium is circulated to perform anti-freezing of the heat medium.