Relay Unit Refrigerant Routing for Integrated Hot Water Supply
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Solution Overview
Problem
Existing air-conditioning apparatus face challenges in readily adding a hot water supply function without increasing costs or requiring significant modifications, such as the need for additional refrigerant circuits and space for hot water units, and suffer from reduced heat exchange performance when integrating a water heat exchanger with the compressor discharge piping.
Innovation Solution
An air-conditioning apparatus design that connects a heat source unit and a relay unit with two refrigerant pipings, allowing for a hot water supply function by using a branching device and flow switching devices to manage refrigerant flow between indoor units and a water heat exchanger, enabling simultaneous cooling, heating, and hot water supply operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a load-side refrigerant circuit is added to enable hot water supply function, then the hot water supply capability is improved, but the cost increases greatly
Solution Approach 1:
The outdoor heat exchanger is designed to serve multiple functions: it acts as a condenser during cooling operation, an evaporator during heating operation, and a hot water heater during hot water supply operation. This multi-functionality eliminates the need for separate load-side refrigerant circuits, thereby reducing cost while maintaining hot water supply capability
Solution Approach 2:
The patent merges the hot water supply function with the existing outdoor heat exchanger and refrigerant circuit. By integrating these functions into a single system rather than adding separate circuits, the patent achieves cost reduction while maintaining versatility
2Adaptability or versatility
If a water heat exchanger is attached to the compressor discharge piping to enable hot water supply, then the hot water supply function is added, but the heat exchange performance deteriorates
Solution Approach 1:
The refrigerant is pre-cooled in the outdoor heat exchanger before being supplied to the water heat exchanger. This preliminary cooling action ensures that the refrigerant enters the water heat exchanger at an optimal temperature, maintaining efficient heat exchange performance while enabling hot water supply function
3Temperature
If the refrigerant is cooled in the heat source unit-side heat exchanger before flowing to the hot water device, then the refrigerant temperature is reduced, but the heat exchange performance of the water heat exchanger deteriorates
Solution Approach 1:
The system dynamically adjusts the refrigerant flow path based on operational requirements. During hot water supply operation, the refrigerant is directed to bypass the outdoor heat exchanger and flow directly to the water heat exchanger, maintaining optimal temperature and heat exchange performance. This dynamic flow control resolves the contradiction between temperature reduction and heat exchange efficiency
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 efficient and cost-effective addition of a hot water supply function without requiring extensive modifications, improving heat exchange performance and operational flexibility by utilizing a carbon dioxide refrigerant that operates in a supercritical state, allowing for high-temperature hot water discharge without additional load-side refrigerant circuits.
Implementation Method 1
a compressor (1) that compresses a refrigerant
Implementation Method 2
a water heat exchanger (31) that exchanges heat between the refrigerant and water
Implementation Method 3
an indoor unit-side heat exchanger (5c to 5e) that exchanges heat between the refrigerant and indoor air
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To provide an air-conditioning apparatus in which a heat source unit and a relay unit are connected by two pipings, and in which a hot water supply function can be readily added. An air-conditioning apparatus in which a relay unit B includes a connection circuit between a first branching unit 10 and a second connecting piping 7 that is capable of connecting a water heat exchanger 31 that exchanges heat between a refrigerant and water.