Air conditioning apparatus with primary and secondary heat exchange cycles
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Solution Overview
Problem
Air-conditioning apparatuses using refrigeration cycles with heat media like water or brine have lower air conditioning performance compared to direct expansion air conditioners, and existing systems lack efficient control methods to optimize refrigerant flow and temperature differences, leading to increased costs and complexity.
Innovation Solution
An air-conditioning apparatus with a primary-side cycle including a compressor, heat source side heat exchanger, and intermediate heat exchanger, and a secondary-side cycle with a pump and use side heat exchanger, where the temperature difference between the heat transfer media is controlled to optimize performance during heating and cooling operations, allowing for adequate actuator control and improved system COP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat is exchanged via a heat medium (water, brine) between refrigerant in the refrigeration cycle and indoor air, then refrigerant leakage risk is reduced, but air conditioning performance becomes lower than direct expansion air conditioners
Solution Approach 1:
The invention changes the temperature parameter of the heat source water to be dynamically adjusted based on outdoor temperature conditions. By setting the heat source water temperature to 7-10°C when outdoor temperature is 0-10°C, and to 12-15°C when outdoor temperature is 10-20°C, the system optimizes heat exchange efficiency while maintaining safety benefits of indirect expansion, thereby resolving the contradiction between reliability and productivity.
2Stability of the object's composition
If the temperature of heat source water is controlled to change on the order of 5 degrees C. for both cooling and heating operations, then stable air conditioning is achieved, but system flexibility and optimization capability are limited
Solution Approach 1:
The invention introduces dynamic temperature control for the heat source water, where the temperature is not fixed but adjusted according to outdoor temperature conditions and operational mode (cooling/heating). The control unit dynamically sets different temperature ranges (7-10°C or 12-15°C for cooling; 35-40°C or 40-45°C for heating) based on real-time conditions, making the system both stable and adaptable.
Solution Approach 2:
The system changes the temperature parameter of heat source water based on outdoor temperature and operational mode. By implementing multiple temperature levels (7-10°C, 12-15°C for cooling; 35-40°C, 40-45°C for heating), the system maintains stability through controlled changes while achieving versatility through adaptive optimization.
3Volume of stationary object
If the difference between inlet and outlet temperatures of water is set to 10 degrees C. or larger to reduce the size of the air-conditioning unit and transport energy, then equipment size and energy consumption are reduced, but control precision and system performance optimization are compromised
Solution Approach 1:
The invention implements precise temperature parameter control by setting specific temperature ranges for heat source water based on outdoor conditions and operational mode. The system maintains temperature differences within optimized ranges (5°C or 10°C) rather than using fixed large differences, achieving both compact size and precise control through dynamic parameter adjustment.
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 apparatus achieves high system COP by controlling temperature differences and actuator operations, reducing energy consumption and costs while enhancing air conditioning performance.
Implementation Method 1
the intermediate heat exchanger exchanging heat between the primary-side heat transfer medium and the secondary-side heat transfer medium
Data Source
AI summary
An air-conditioning apparatus has a controller that sets the target value of a difference between the temperatures of a secondary-side heat transfer medium at positions before and after a plurality of use side heat exchangers during a rated operation in a heating operation so as to have a larger magnitude than a target value of the difference between the temperatures of the secondary-side heat transfer medium at positions before and after the plurality of use side heat exchangers during a rated operation in the cooling operation.