Heat Medium Relay Unit Layout for Leak-Safe HVAC Serviceability
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Solution Overview
Problem
Conventional air-conditioning systems face issues with refrigerant leakage, high energy consumption due to long heat medium circulation paths, complex construction, noise, and high failure rates of heat medium flow control devices, as well as inefficiencies in heat exchanger configurations that lead to wasted energy and poor ease of construction.
Innovation Solution
A heat medium relay unit that includes a heat exchanger, heat medium flow control devices, and flow switching devices, where the heat medium flow control devices are maintained on a service side for improved accessibility, and the heat medium is circulated without refrigerant in indoor units to prevent leakage and enhance safety, with a configuration that reduces energy consumption by shortening circulation paths and simplifying construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant is circulated to indoor units, then cooling and heating operations can be performed, but refrigerant leakage into indoor space becomes possible
Solution Approach 1:
The system is divided into two separate circulation paths: a refrigerant circuit confined to the outdoor unit and a heat medium circuit that serves indoor units. This segmentation isolates the refrigerant to the outdoor unit, eliminating the risk of refrigerant leakage into indoor spaces while maintaining the cooling and heating functions.
Solution Approach 2:
A heat medium (such as water or brine) is introduced as an intermediary substance that transfers thermal energy from the refrigerant in the outdoor unit to the indoor units. The heat medium circulates through the heat medium relay unit and connects to indoor units via heat exchangers, enabling heat transfer without requiring refrigerant to be present in indoor units.
2Adaptability or versatility
If heat medium circulation path is extended to reach indoor units, then heating and cooling can be provided to indoor spaces, but energy consumption due to conveyance power increases
Solution Approach 1:
The heat medium relay unit acts as an intermediary hub that receives thermal energy from the outdoor unit and distributes it to multiple indoor units. By concentrating the heat exchange function in the outdoor unit and using the heat medium relay unit as a distribution point, the system minimizes the total circulation path length compared to having individual heat exchangers at each indoor unit, thereby reducing conveyance energy consumption.
3Device complexity
If heat medium flow control devices are disposed inside the heat medium relay unit, then system integration is improved, but serviceability and accessibility for maintenance deteriorate
Solution Approach 1:
The heat medium relay unit is designed with a separable structure where the heat medium flow control devices are mounted on the front surface, accessible from the outside. This segmentation allows maintenance personnel to access and service the flow control devices without disassembling the entire relay unit, improving serviceability while maintaining system integration.
Solution Approach 2:
The heat medium flow control devices are positioned on the front surface of the relay unit, creating an accessible external interface. This spatial arrangement in a different dimension (external surface vs. internal mounting) enables easy access for maintenance while keeping the devices integrated into the overall system architecture.
4Adaptability or versatility
If four water pipes are used to connect outdoor unit and indoor units for heat recovery chiller, then cooling or heating can be selected in each indoor unit, but ease of construction deteriorates
Solution Approach 1:
The heat medium circulation system is designed to handle both cooling and heating operations through a single unified pipe configuration. The heat medium relay unit and associated flow control devices enable the same piping infrastructure to serve dual functions, eliminating the need for separate four-pipe systems for cooling and heating, thereby simplifying construction while maintaining operational versatility.
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 solution improves serviceability and safety by preventing refrigerant leakage, reducing energy consumption, and simplifying construction, while maintaining efficient heat transfer and operation of air-conditioning systems.
Implementation Method 1
a heat exchanger related to heat medium that exchanges heat between a refrigerant in a refrigerant circuit in which the refrigerant is circulated by being discharged from a compressor provided in an outdoor unit and a heat medium, which is different from the refrigerant, in a heat medium circuit
Data Source
AI summary
Obtained is a heat medium relay unit capable of having improved serviceability and an air-conditioning apparatus equipped with the heat medium relay unit.Heat medium flow control devices are each disposed below a corresponding one of the first heat medium flow switching devices. The heat medium flow control devices are similarly disposed in a zigzag manner along with the zigzag arrangement of the first heat medium flow switching devices.