Two-Stage Refrigerant Circuit for Multi-Evaporator Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing refrigerant circuits in motor vehicles are not energy-efficient, particularly when cooling multiple components to different temperature levels, leading to increased energy consumption and noise from air conditioning units due to varying pressure levels and cooling requirements.
Innovation Solution
A refrigerant circuit with a two-stage compressor and multiple evaporators connected via different supply lines, allowing for adjustable pressure levels and efficient cooling of batteries and air to various temperature settings, including the use of a third evaporator for further cooling of air to lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single compressor operates multiple evaporators at different temperature levels, then the system can cool multiple components (battery and air conditioning), but the compressor must operate at the lowest pressure level to satisfy the coldest evaporator, resulting in increased energy consumption
Solution Approach 1:
The compressor is divided into two independent stages: a first stage compressor and a second stage compressor. Each stage can independently compress refrigerant to different pressure levels and supply different evaporators. This segmentation allows each compressor to operate at optimal pressure levels for its specific evaporator, avoiding the energy penalty of operating at the lowest pressure level for all evaporators.
Solution Approach 2:
The system dynamically switches between different operational modes depending on cooling requirements. When only one evaporator needs cooling, only the corresponding compressor stage operates. When both evaporators need cooling, both stages operate simultaneously. This dynamic operation optimizes energy consumption by avoiding unnecessary compression work.
2Object-affected harmful factors
If the air supply temperature is lowered to below zero degrees Celsius to reduce fan noise, then the cooling capacity is maintained while noise is reduced, but the compressor must operate at even lower pressure levels, increasing energy consumption further
Solution Approach 1:
The second evaporator is dedicated to air conditioning and can be supplied by the second stage compressor at optimized pressure levels. This allows the air conditioning evaporator to operate at lower temperatures (below zero) for noise reduction while the battery evaporator operates at higher temperatures, avoiding the need for the entire system to operate at the lowest pressure level.
Solution Approach 2:
Different evaporators are provided with different pressure levels according to their specific cooling requirements. The air conditioning evaporator receives refrigerant at pressure levels optimized for sub-zero temperatures, while the battery evaporator receives refrigerant at pressure levels optimized for higher temperatures, allowing each to operate efficiently for its specific function.
3Temperature
If different temperature levels are provided for battery tempering (20°C) and air conditioning (2°C or -10°C), then both components can be cooled effectively, but the pressure level on the suction side must be based on the lowest temperature, reducing system efficiency
Solution Approach 1:
The refrigerant circuit is segmented into two independent compression paths. The first stage compressor handles refrigerant for the battery evaporator, while the second stage compressor handles refrigerant for the air conditioning evaporator. This allows each path to operate at pressure levels optimized for its target temperature, eliminating energy losses from operating the entire system at the lowest pressure level.
Solution Approach 2:
The system changes the pressure parameter independently for different evaporators based on their temperature requirements. The first stage compressor operates at pressure levels corresponding to 20°C battery cooling, while the second stage compressor operates at pressure levels corresponding to 2°C or -10°C air conditioning, optimizing energy efficiency for each temperature level.
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 enables energy-efficient operation by optimizing cooling capacities for each evaporator, reducing energy consumption and fan noise while maintaining effective temperature control for batteries and interior air.
Implementation Method 1
at least one compressor (2) for compressing a refrigerant
Implementation Method 2
a condenser (5) for cooling and liquefying the compressed refrigerant
Implementation Method 3
at least one evaporator for returning the liquefied refrigerant to the gaseous state. The at least one evaporator is used to cool fluid flows or components
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a refrigerant circuit (1), at least comprising a compressor (2) with an upstream suction side (3) and a downstream pressure side (4), a condenser (5), a first evaporator (6), and at least one second evaporator (7), wherein the compressor (2) is an at least two-stage compressor which has a first supply line (8) on the suction side (3) leading to a first stage (9) of the compressor (2), said first supply line having a first pressure level, and a second supply line (10) leading to a second stage (11) of the compressor (2), said second supply line having a second pressure level, wherein the second pressure level is higher than the first pressure level, and the first evaporator (6) and the second evaporator (7) can be at least temporarily connected to the compressor (2) via different supply lines (8, 10). The invention additionally relates to a method for operating a refrigerant circuit.