Multi-connected air conditioner with refrigerant and water system
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Solution Overview
Problem
Current air conditioning systems face inefficiencies in energy usage and operational flexibility, particularly in managing simultaneous cooling and heating demands, low load rate conditions, and the integration of natural energy sources, leading to suboptimal performance and comfort levels.
Innovation Solution
The multi-mode MACRAW system employs independent refrigerant circulation loops for each air conditioning unit, with multiple heat exchanger channels and circulation loops that allow for flexible operation modes, including simultaneous cooling and heating, and efficient use of natural energy, enabling stable and efficient operation across varying load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a combined system of chiller units and fan coil units is used to provide long-distance energy transmission, then energy transmission distance is improved, but system operating efficiency deteriorates due to added heat exchange links between refrigerant and water
Solution Approach 1:
The system is divided into independent refrigerant circulation loops for each air conditioning unit, with each unit having its own compressor and heat exchangers. This segmentation eliminates the need for centralized refrigerant-water heat exchange links while maintaining long-distance energy transmission capability through separate refrigerant lines to each unit.
Solution Approach 2:
A water circulation loop acts as an intermediary to connect multiple indoor heat exchangers to outdoor heat exchangers. This water loop enables heat transfer between different refrigerant loops without requiring direct refrigerant-water heat exchange, thus maintaining efficiency while enabling long-distance transmission and multiple operation modes.
2Loss of energy
If VRF systems adopt direct expansion scheme to improve unit efficiency through direct heat exchange between refrigerant and air, then unit operating efficiency is improved, but long-distance energy transport capability deteriorates and ability to utilize natural energy or municipal water for free cooling and heating is limited
Solution Approach 1:
Each air conditioning unit is designed with multi-functionality, capable of operating in multiple modes including air-cooled, water-cooled, simultaneous cooling and heating, and free cooling/heating using natural energy or municipal water. The outdoor heat exchanger can switch between air and water cooling modes, and the system can utilize evaporator cold for free cooling, thus achieving both efficiency and versatility.
Solution Approach 2:
The water circulation loop serves as a mediator that enables long-distance energy transport by connecting outdoor heat exchangers to multiple indoor units. This water loop allows the system to utilize natural energy sources and municipal water for free cooling and heating while maintaining efficient refrigerant-to-air heat exchange at each unit.
3Adaptability or versatility
If heat recovery VRF systems are used to handle simultaneous cooling and heating demands in different rooms, then heat recovery capability is improved, but system size constraints and low load efficiency deteriorate
Solution Approach 1:
The system dynamically adjusts operation modes based on load conditions. Each air conditioning unit can independently switch between different modes (air-cooled, water-cooled, simultaneous cooling and heating, free cooling/heating) to optimize performance at various load rates. The water circulation loop dynamically connects or disconnects different indoor units to match heating and cooling demands, improving low load efficiency.
Solution Approach 2:
The system segments heat recovery into independent refrigerant loops for each unit, allowing flexible matching of heating and cooling loads without being constrained by centralized system size. This segmentation enables efficient heat recovery even at low load conditions by connecting only the necessary units through the water circulation loop.
4Adaptability or versatility
If water loop heat pumps are used for heat recovery in public buildings, then simultaneous cooling and heating in different rooms is improved, but cold and hot water mixing problems within the loop deteriorate
Solution Approach 1:
The system segments the water circulation into separate loops for cooling and heating, connected through outdoor heat exchangers that act as thermal bridges. This segmentation prevents direct mixing of cold and hot water while enabling simultaneous cooling and heating in different rooms through the water-cooled mode and heat recovery functionality.
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 system enhances energy efficiency and operational flexibility by allowing for multiple operation modes, effectively managing simultaneous cooling and heating, and utilizing natural energy, thereby ensuring stable and efficient air conditioning performance throughout the year.
Implementation Method 1
a heat exchange link between the refrigerant and the water is added
Implementation Method 2
a refrigerant circulation loop, each of the refrigerant circulation loop is provided with a compressor for driving the refrigerant to flow
Data Source
AI summary
A Multi-connected Air Conditioner with Refrigerant And Water (MACRAW) multi mode system, includes refrigerant circulation loops of multiple air conditioning units, an outdoor heat exchanger and an indoor heat exchanger, a first circulation loop, a second circulation loop and a main heat exchanger. The first circulation loop and the second circulation loop exchange heat through the main heat exchanger, a second medium channel is provided in each of the outdoor heat exchanger and the indoor heat exchanger, the first circulation loop and the second circulation loop, through each second medium channel, exchange heat with a first medium channel and/or a first air heat exchange channel in each outdoor heat exchanger, and with the second medium channel and/or a second air heat exchange channel in indoor heat exchanger.