Two-Stage Heat Pump Circuit With Series Water Heating Path
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Solution Overview
Problem
Conventional heat pump systems face complexity in configuration and flow rate control due to parallel connection of water groups through intercoolers and gas coolers, making it difficult to adjust water flow rates and temperatures effectively.
Innovation Solution
A heat pump system with a multistage compression circuit where the utilization-side heat exchanger and intercooler are connected in series, allowing for simplified configuration and easy adjustment of water flow rates, with a control device adjusting decompression amounts to achieve a refrigerant circulation ratio of 30% to 60% and heating capacity ratio of 15% to 25% between the intercooler and utilization-side heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If water groups are connected in parallel through intercooler and gas cooler, then heat exchange capacity is improved, but device complexity and flow rate control difficulty increase
Solution Approach 1:
The patent merges the intercooler and gas cooler into a single integrated heat exchanger unit. The refrigerant flow path remains separate (high-stage refrigerant to intercooler, low-stage refrigerant to gas cooler), but the water/liquid flow path is unified into one circuit, eliminating the need for parallel connections and mixing valves. This reduces device complexity while maintaining heat exchange capacity.
Solution Approach 2:
The unified heat exchanger performs multiple functions: it acts as both an intercooler (cooling high-stage refrigerant) and a gas cooler (cooling low-stage refrigerant), while also serving as a single water heating circuit. This multi-functionality eliminates the need for separate parallel water circuits and their associated control mechanisms.
2Power
If water groups flow through parallel paths and merge after heating, then total heating capacity increases, but flow rate control and temperature control become complicated
Solution Approach 1:
The patent combines multiple water flow paths into a single unified water circuit that passes sequentially through both the intercooler section and gas cooler section of the heat exchanger. This eliminates the need for mixing valves and complex flow distribution control, while still providing total heating capacity from both refrigerant streams.
Solution Approach 2:
The unified water circuit provides continuous flow through the entire heat exchanger assembly, maintaining steady-state operation without the need to balance or coordinate multiple parallel flows. The water continuously absorbs heat from both high-stage and low-stage refrigerant streams in sequence, simplifying control while maintaining total heating capacity.
3Power
If mixing valve is added to adjust water distribution ratio, then heating capacity distribution is improved, but device complexity increases
Solution Approach 1:
The patent eliminates the mixing valve by merging the water circuits into one unified path. The unified water flow naturally receives heat from both refrigerant streams sequentially, providing flexible heating capacity distribution through the inherent thermal characteristics of the system rather than mechanical flow control devices.
Solution Approach 2:
The unified water circuit self-regulates its heat absorption from the two refrigerant streams based on the refrigerant conditions and water flow rate. The system automatically balances the heating capacity contribution from each refrigerant stream without requiring external mixing valves or active control mechanisms, achieving heating capacity distribution through passive thermal equilibrium.
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
This configuration simplifies the utilization-side heating medium circuit, enhances heat transfer efficiency, and improves energy saving performance by increasing the flow rate of the heating medium, allowing for easier temperature control and increased operational efficiency.
Implementation Method 1
a utilization-side heat exchanger for heat-exchanging between the refrigerant flowing from the high stage-side compressing mechanism to the first expanding device and the utilization-side heating medium flowing through the utilization-side heating medium circuit
Implementation Method 2
an intercooler for heat-exchanging between the refrigerant discharged from the low stage-side compressing mechanism and the utilization-side heating medium flowing through the utilization-side heating medium circuit
Data Source
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AI summary
The present invention provides a heat pump system including: a heat pump circuit 10 formed by sequentially connecting, to one another, a compressing mechanism 11 including a high stage-side compressing mechanism 11b and a low stage-side compressing mechanism 11a, a first expanding device 15 and a heat source-side heat exchanger 16 through at least a pipe; a utilization-side heat exchanger 12 for heat-exchanging between the refrigerant flowing from the high stage-side compressing mechanism 11b to the first expanding device 15 and the utilization-side heating medium flowing through the utilization-side heating medium circuit 30; and an injection refrigerant circuit 20 in which the refrigerant flowing through the heat pump circuit 10 is branched off from a position between the utilization-side heat exchanger 12 and the first expanding device 15, the branched refrigerant is decompressed by a second expanding device 18, thereafter, the refrigerant joins up, with the refrigerant after it flows out from the intercooler 17, and the joined refrigerant is sucked into the high stage-side compressing mechanism 11b; the utilization-side heat exchanger 12 and the intercooler 17 are connected to each other in series in the utilization-side heating medium circuit 30. Therefore, it is possible to simplify both a configuration of the utilization-side heating medium circuit 30 and the control of a flow rate of the utilization-side heating medium.