Heat pump
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Solution Overview
Problem
Heat pumps face challenges in operating over a large temperature range without risking compressor failure due to increased load from gas injection.
Innovation Solution
A heat pump system with a gas and liquid injection valve system, controlled by a controller, that adjusts refrigerant flow to manage compressor load and temperature, including a gas-liquid separator and economizing heat exchanger to optimize operation across varying temperature differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas injection is increased to improve compressor capacity and coefficient of performance, then the compressor capacity and coefficient of performance are improved, but the load on the compressor increases which may result in compressor failure
Solution Approach 1:
The system dynamically adjusts the amount of gas injected into the compressor based on operating conditions. The control unit monitors the temperature difference between utilization side and heat source side, and adjusts the gas injection valve accordingly to optimize compressor capacity while preventing overload and failure.
Solution Approach 2:
The system changes the injection parameter (amount of gas injected) based on the temperature difference between utilization side and heat source side. When the temperature difference is small, more gas is injected to maximize capacity; when the temperature difference is large, gas injection is reduced to prevent compressor failure.
2Productivity
If gas injection is increased to meet compressor capacity demands in large temperature difference situations, then the compressor capacity is increased, but compressor failure occurs through overloading
Solution Approach 1:
The control unit continuously monitors the temperature difference between utilization side and heat source side, and uses this feedback to adjust the gas injection amount. This closed-loop control prevents compressor overloading by reducing gas injection when the temperature difference indicates high compressor load conditions.
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 system allows the heat pump to operate efficiently over a wide range while preventing compressor failure by dynamically adjusting refrigerant injection, enhancing capacity and performance.
Implementation Method 1
the controller is configured to operate the gas injection valve to inject at least partly gaseous refrigerant into the compressor through the injection port
Implementation Method 2
the controller is further configured to operate the liquid injection valve to inject substantially liquid refrigerant into the compressor through the suction port of the compressor
Implementation Method 3
a compressor for compressing a refrigerant
Implementation Method 4
a utilization side heat exchanger, a main expansion mechanism and a heat source side heat exchanger arranged in a refrigeration path with a medium circulated through these components to transfer heat
Data Source
AI summary
A heat pump includes a compressor, a first heat exchanger, a main expansion mechanism and a second heat exchanger arranged in a refrigeration path, the compressor having a suction port, a compression port and an injection port; a gas injection valve connected on a first side to the refrigeration path between the first heat exchanger and the main expansion mechanism and on a second side to the injection port of the compressor; a liquid injection valve connected on a first side to the refrigeration path between the first heat exchanger and the main expansion mechanism and on a second side between the second heat exchanger and the suction port of the compressor; and a controller configured to operate the gas injection valve to inject partly gaseous refrigerant into the compressor, and operate the liquid injection valve to inject liquid refrigerant into the compressor through the suction port of the compressor.