Two-Stage Refrigerant Injection in Rotary Heat Pumps for Cold Heating
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Solution Overview
Problem
Conventional heat pumps face challenges in maintaining sufficient cooling and heating performance, especially in varying outdoor temperatures, and require costly upgrades or additional units to improve performance in cold conditions.
Innovation Solution
A heat pump design featuring a rotary compression device with multiple compression chambers and refrigerant injection flow paths that bypass refrigerant between the condenser and evaporator, allowing for multistage compression and increased refrigerant flow rates, enhancing heating performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing heat pump is changed into the new heat pump having larger capacity or an extra pump is added, then heating performance in cold conditions is improved, but installation cost and space requirements increase
Solution Approach 1:
The rotary compressor is divided into multiple compression chambers (first compression chamber and second compression chamber) that operate in sequence. This segmentation allows multistage compression without requiring multiple separate compressors, thereby improving heating performance while avoiding increased installation complexity and space requirements
Solution Approach 2:
The patent implements dynamic refrigerant injection where liquid refrigerant is injected into the compression chambers during operation. This dynamic adjustment of refrigerant state and flow enables the system to adapt to varying heating loads and outdoor temperatures, improving reliability without requiring multiple fixed-capacity units
2Productivity
If refrigerant flow rate is increased to improve heating performance, then heating capacity in cold areas is enhanced, but system complexity and cost increase
Solution Approach 1:
Liquid refrigerant is injected into the compression chambers before compression occurs. This preliminary action of injecting refrigerant in liquid form allows the system to increase refrigerant flow rate and heating capacity without requiring complex additional flow control mechanisms, as the liquid injection naturally regulates the refrigerant amount
Solution Approach 2:
The patent uses liquid refrigerant injection (hydraulic principle) to control refrigerant flow rate. By injecting liquid refrigerant directly into the compression chambers, the system achieves high refrigerant flow rates and heating capacity without mechanical complexity, utilizing fluid dynamics rather than mechanical flow control devices
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 design improves heating performance in cold conditions, increases refrigerant flow rates, reduces the size of outdoor units, and enhances the reliability and efficiency of the rotary compressor, while simplifying the structure and reducing costs.
Implementation Method 1
a rotary compression device having a plurality of compression chambers
Implementation Method 2
a condenser for condensing refrigerant passed through the rotary compression device
Implementation Method 3
an expansion device for throttling refrigerant passed through the condenser
Implementation Method 4
an evaporator for evaporating refrigerant expanded by the expansion device
Implementation Method 5
a first refrigerant injection flow path which is bypassed at the space between the condenser and the evaporator and injects refrigerant to one of the plurality of compression chambers
Data Source
AI summary
A heat pump according to the present invention comprises a plurality of the compression chambers, and compresses refrigerant with multistage, and injects vapor refrigerant into the space between the plurality of the compression chambers by using the first refrigerant injection flow path and the second refrigerant injection flow path. Performance and efficiency of the heat pump can be improved compared with non-injection, as flow rate of the refrigerant circulating the indoor heat exchanger is increased. Thus heating performance can be improved also in the extremely cold environmental condition such as the cold area by increasing the injection flow rate. Also, because the heat pump according to the present invention comprises the first refrigerant injection flow path and the second refrigerant injection flow path, refrigerant is injected twice. Thus, as the injection flow rate of the refrigerant is increased, heating capacity can be improved. Also, the difference between the suction pressure and the discharge pressure of the rotary compressor may be decreased, and thus the reliability and the performance of the rotary compressor can be improved.