Multistage Heat Pump Compression With Dual Refrigerant Injection
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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 significant upgrades or additional units, which are costly and space-intensive.
Innovation Solution
A heat pump design featuring multiple compression chambers with dual refrigerant injection flow paths that increase the refrigerant flow rate through the indoor heat exchanger, allowing for multistage compression and improved heating performance in cold conditions, while reducing the size of the outdoor unit and enhancing compressor reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
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 areas is improved, but installation cost and space requirements increase
Solution Approach 1:
The compression process is segmented into multiple stages with intermediate refrigerant injection. The compressor includes a first compression chamber and a second compression chamber, with refrigerant injected between stages. This segmentation allows efficient compression at each stage while maintaining overall system compactness, avoiding the need for larger capacity units or additional pumps.
Solution Approach 2:
Refrigerant is used as an intermediary substance injected into the compression chamber between the first and second compression chambers. This intermediate refrigerant injection serves as a mediator to cool the compressed refrigerant, increase density, and improve mass flow rate through the indoor heat exchanger, thereby enhancing heating performance without requiring larger equipment.
2Productivity
If refrigerant flow rate through the indoor heat exchanger is increased, then heating performance is improved, but compressor discharge temperature increases
Solution Approach 1:
Refrigerant is injected into the compression chamber before the second compression stage as a preliminary action. This injected refrigerant pre-cools the refrigerant being compressed, preventing excessive temperature rise during compression. The preliminary cooling action allows increased refrigerant flow rate and improved heating performance while maintaining acceptable discharge temperatures.
Solution Approach 2:
The injection of intermediate refrigerant changes the temperature and pressure parameters of the refrigerant during the compression process. By introducing refrigerant at a specific state (lower temperature, intermediate pressure) into the compression chamber, the overall discharge temperature is controlled while enabling higher mass flow rates through the system.
3Device complexity
If single-stage compression is used, then device structure is simple, but heating performance in cold areas is insufficient
Solution Approach 1:
The compression process is divided into two stages with an intermediate injection point. The first compression chamber performs initial compression, then refrigerant is injected, followed by second compression in the second compression chamber. This segmentation improves heating performance in cold areas by enabling better control of compression ratios and refrigerant temperature, while the entire multi-stage process occurs within a single compressor body, maintaining structural simplicity.
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 enhances heating performance, reduces the size of the outdoor unit, and improves compressor reliability by increasing refrigerant flow rate and compression efficiency, addressing the limitations of conventional heat pumps in extreme temperatures.
Implementation Method 1
a rotary compression device (10) which has a plurality of compression chambers, and compresses refrigerant with multistage
Implementation Method 2
an indoor heat exchanger (20) which heats or cools air in an indoor space, by using heat exchanged with refrigerant
Implementation Method 3
a first expansion valve (30) for expanding refrigerant which passed through the condenser (20)
Implementation Method 4
an outdoor heat exchanger (70) which performs heat exchange with refrigerant in an outdoor space
Data Source
Figure 1~2
Figure 3
Figure 4~5
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 (52) and the second refrigerant injection flow path (62). 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 (61) 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 (52) and the second refrigerant injection flow path (62), 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 (100) may be decreased, and thus the reliability and the performance of the rotary compressor (100) can be improved.