Free cooling refrigeration system
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Refrigeration systems face inefficiencies in utilizing ambient low temperatures for cooling, particularly when using freeze-protected fluids, which have higher costs, viscosity, and lower heat transfer rates compared to water, and existing systems lack efficient modes to adapt to varying ambient conditions.
Innovation Solution
A refrigeration system with a free cooling system that includes an independent loop for a freeze-protected fluid to transfer heat from a cooling fluid to ambient air, and a heat exchanger that receives refrigerant to transfer heat to the freeze-protected fluid, allowing for operation in multiple modes to optimize cooling capacity based on ambient temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If freeze-protected fluid is used in the cooling loop, then the system can operate at lower temperatures without freezing, but the fluid has higher costs, higher viscosity, and lower heat transfer rates
Solution Approach 1:
The system divides the cooling function into two separate loops: a primary cooling loop using inexpensive water with high heat transfer efficiency, and a secondary free cooling loop using freeze-protected fluid for ambient heat rejection. This segmentation allows each fluid to be optimized for its specific function, reducing overall system cost while maintaining low-temperature operation capability.
Solution Approach 2:
A heat exchanger serves as an intermediary between the primary cooling loop and the free cooling loop, allowing heat transfer between the two fluids without direct mixing. This enables the system to utilize the advantages of both fluids: water's superior heat transfer properties and freeze-protected fluid's low-temperature protection capability.
2Temperature
If freeze-protected fluid is used in the cooling loop, then the system can operate at lower temperatures without freezing, but the fluid has higher viscosity and lower heat transfer rates
Solution Approach 1:
The cooling system is segmented into two distinct loops with different fluid choices optimized for their respective functions. The primary loop uses water for high heat transfer rate applications, while the free cooling loop uses freeze-protected fluid for ambient temperature heat rejection, thereby avoiding the heat transfer penalty in the critical cooling path.
Solution Approach 2:
The heat exchanger acts as an intermediary that transfers thermal energy from the high heat transfer rate water loop to the freeze-protected fluid loop, enabling the system to maintain high overall heat transfer efficiency while still achieving low-temperature operation through the ambient cooling path.
3Adaptability or versatility
If a separate heat exchanger or coil portion is used for free cooling mode, then the system can exploit ambient low temperatures, but the system complexity increases
Solution Approach 1:
The patent merges the free cooling heat exchanger with the primary cooling loop heat exchanger into a single integrated component. This allows the same heat exchanger to serve dual purposes: cooling the primary loop during normal operation and enabling free cooling by allowing ambient air to cool the refrigerant directly, thereby reducing system complexity while maintaining free cooling capability.
Solution Approach 2:
The heat exchanger is designed with multi-functionality to operate in both normal cooling mode and free cooling mode. During free cooling, the heat exchanger serves as both the primary cooling device and the ambient heat rejection device, eliminating the need for a separate free cooling coil and simplifying the overall system structure.
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 system efficiently utilizes ambient low temperatures for cooling, reduces costs by minimizing the use of freeze-protected fluid, and provides additional cooling capacity by integrating vapor-compression refrigeration, enhancing overall system efficiency and adaptability.
Implementation Method 1
a first circuit configured to transfer heat from a first cooling fluid to a second cooling fluid circulating within an independent loop of the free cooling system
Implementation Method 2
The independent loop is configured to transfer heat from the second cooling fluid to ambient air
Implementation Method 3
a heat exchanger configured to receive refrigerant and to transfer heat from the refrigerant to the second cooling fluid
Implementation Method 4
The fluid flowing within the closed loop is generally formulated to undergo phase changes within the normal operating temperatures and pressures of the system so that considerable quantities of heat can be exchanged by virtue of the latent heat of vaporization of the fluid
Implementation Method 5
an evaporator configured to remove heat from a first cooling fluid circulating through a cooling loop
Implementation Method 6
considerable quantities of heat can be exchanged by virtue of the latent heat of vaporization of the fluid
Data Source
AI summary
A refrigeration system includes a chiller with an integrated free cooling system and refrigeration system. In certain embodiments, the chiller may be a single package unit with all equipment housed within the same support frame. The chiller may generally include three modes of operation: a first mode that employs free cooling, a second mode that employs free cooling and implements a refrigeration cycle, and a third mode that uses the free cooling system provide additional cooling capacity for the refrigeration system. The free cooling system includes an independent loop configured to transfer heat from a cooling fluid circulating within the free cooling system to the ambient air.