Intermediate Subcooling Heat Exchanger for Higher Refrigeration Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing refrigerant systems face challenges in increasing capacity without adding complexity or expense, as economizer cycles require additional components and 'liquid-suction' heat exchangers can reduce cooling capacity by superheating vapor, leading to reduced refrigerant mass flow.
Innovation Solution
Incorporating an air-to-refrigerant heat exchanger between the outdoor heat rejection heat exchanger and indoor expansion device, exposed to indoor air temperatures, to further cool the refrigerant and enhance system capacity, with optional bypass during temperature equality between outdoor and indoor environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an economizer cycle is used to cool the refrigerant, then the refrigerant system capacity increases, but the device complexity and expense increase substantially due to additional components and vapor injection compressor requirements
Solution Approach 1:
The invention extracts the essential cooling function from the complex economizer cycle and implements it through a simpler heat exchanger arrangement. By taking out only the necessary heat transfer capability and placing it in a straightforward configuration between the heat rejection heat exchanger and expansion device, the system achieves subcooling without the complexity of economizer cycles or vapor injection compressors
Solution Approach 2:
The invention replaces expensive, complex components (economizer cycle components, vapor injection compressors) with a simpler, more economical heat exchanger design. This disposable-like approach uses basic heat transfer principles rather than sophisticated control systems and additional mechanical components
2Temperature
If a liquid-suction heat exchanger is used to cool the refrigerant, then some cooling effect is achieved, but the cooling capacity is reduced due to vapor superheating that decreases refrigerant density and mass flow
Solution Approach 1:
The invention applies local quality by positioning the heat exchanger to provide cooling only where needed - specifically subcooling the liquid refrigerant after the heat rejection heat exchanger. This localized cooling approach avoids the problem of liquid-suction heat exchangers that cool the refrigerant too early, causing unwanted vapor superheating and reduced mass flow at the compressor
Solution Approach 2:
The invention performs preliminary cooling action at the optimal point in the cycle - subcooling the liquid refrigerant immediately after heat rejection and before the expansion device. This preliminary subcooling increases the refrigerant's cooling potential without interfering with compressor suction conditions, unlike liquid-suction heat exchangers that cool too early
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 increases refrigerant cooling capacity by leveraging temperature differences, providing greater cooling effects in conditioned spaces while maintaining overall system efficiency and reducing compressor power consumption.
Implementation Method 1
an additional air-to-refrigerant heat exchanger between an outdoor heat rejection heat exchanger and an indoor expansion device, with this heat exchanger being exposed to the indoor air temperatures to thereby further cool the refrigerant exiting the heat rejection heat exchanger
Implementation Method 2
outdoor heat rejection heat exchanger
Data Source
AI summary
A refrigerant system operates in an environment defined by three distinct temperature levels, such as, for instance, the outdoor ambient temperature level, the indoor temperature level and the refrigeration temperature level. The refrigerant system is provided with an air-to-refrigerant heat exchanger located within the general indoor environment and connected to receive the flow of refrigerant from a heat rejection heat exchanger. The air-to-refrigerant heat exchanger gives off heat to the indoor air and in the process further cools the refrigerant flowing to an expansion device to thereby increase the cooling effect provided by an evaporator to the refrigeration area. Provisions are also made to partially or entirely bypass the air-to-refrigerant heat exchanger and/or the heat rejection heat exchanger, on a selective basis.