Two-Pipe Vapor Injection Outdoor Unit for Low-Temperature Heating
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Solution Overview
Problem
Conventional two-pipe multi-split systems face challenges in achieving enhanced vapor injection due to low pressure at the outdoor unit, leading to insufficient heating capacity, especially in low-temperature environments, and high exhaust superheat in high-pressure environments.
Innovation Solution
A two-pipe enhanced-vapor-injection outdoor unit is designed with an enhanced-vapor-injection compressor, a supercooler with interconnected heat-exchange flow paths, and a throttling assembly to increase refrigerant circulation, allowing direct injection of gaseous refrigerant for enhanced compression, and includes solenoid and check valves for flow control, enabling improved heating capacity and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional two-pipe multi-split system is used, then system structure is simple, but heating capacity is insufficient in low-temperature environment
Solution Approach 1:
The system divides refrigerant flow into multiple paths using flow division valves, separating the refrigerant circulation into a first circulation path through the outdoor heat exchanger and a second circulation path through the indoor heat exchangers, allowing independent control of each path to optimize heating capacity while maintaining simple two-pipe structure
Solution Approach 2:
The system changes refrigerant parameters by injecting high-temperature high-pressure liquid refrigerant into the suction port of the compressor, and by using supercooling to increase refrigerant temperature before injection, thereby improving vapor density and heating capacity without complicating the basic two-pipe structure
2Device complexity
If conventional two-pipe system is used, then system structure is simple, but heating capacity is insufficient at low temperature due to low pressure
Solution Approach 1:
The system performs preliminary heating by passing refrigerant through the outdoor heat exchanger before compression, and uses supercooling to pre-heat the liquid refrigerant before injection, ensuring the refrigerant is in optimal state for compression and injection even in low-temperature environments
Solution Approach 2:
The system changes the temperature and pressure parameters of the refrigerant by using supercooling to increase liquid refrigerant temperature and by controlling the injection timing, thereby expanding the heating operation temperature range while keeping the two-pipe structure simple
3Power
If enhanced vapor injection is attempted in conventional two-pipe system, then heating capacity may improve, but exhaust superheat degree increases in high-pressure environment
Solution Approach 1:
The system uses a temperature sensor to detect the temperature of refrigerant at the injection port and provides feedback control to the injection valve, adjusting the injection amount to maintain optimal superheat degree and prevent excessive exhaust superheat while maximizing heating capacity
Solution Approach 2:
The system dynamically adjusts the injection amount of refrigerant based on real-time operating conditions such as suction temperature and pressure, allowing optimal control of the vapor injection process to improve heating capacity while preventing excessive exhaust superheat in high-pressure environments
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 significantly enhances heating capacity at low temperatures, expands the operational range, and reduces energy consumption by utilizing heat recovery, achieving efficient heating and cooling modes while simplifying the system structure and reducing material costs.
Implementation Method 1
a supercooler (20) including a main heat-exchange flow path and an auxiliary heat-exchange flow path communicated with each other
Implementation Method 2
an enhanced-vapor-injection compressor (16) having a gas discharge port (162), a gas return port (164) and an injection port (166)
Implementation Method 3
an outdoor heat exchanger (10)
Implementation Method 4
a throttling assembly (22) having a first end connected with an outlet of the main heat-exchange flow path, and a second end connected with an inlet of the outdoor heat exchanger (10)
Data Source
AI summary
A two-pipe enhanced-vapor-injection outdoor unit and a multi-split system are provided. The two-pipe enhanced-vapor-injection outdoor unit includes: an outdoor heat exchanger and a second port; an enhanced-vapor-injection compressor, including a gas discharge port, a gas return port and an injection port; a reversing assembly, including first to fourth ends; a supercooler, including a main heat-exchange flow path and an auxiliary heat-exchange flow path communicated with each other, the main heat-exchange flow path being connected to the second port, the auxiliary heat-exchange flow path being connected to the injection port; and a throttling assembly having a first end connected to an outlet of the main heat-exchange flow path, and a second end connected to an inlet of the outdoor heat exchanger.