Hybrid Refrigerant Cooling with Compressor Bypass in Cold Weather
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Solution Overview
Problem
Conventional vapor compression refrigeration systems fail to operate efficiently in cold weather due to refrigerant migration to the coldest parts of the system, leading to compressor shutdown and the need for energy-intensive mechanical cooling.
Innovation Solution
A hybrid cooling system that allows for 'free' cooling by bypassing the compressor and using a liquid refrigerant pump, combined with programmable control, automated ball valves, and a receiver to manage refrigerant flow, enabling operation with renewable energy sources and efficient energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional vapor compression refrigeration system is used, then cooling can be achieved during warm months, but the system fails to operate efficiently in cold weather due to refrigerant migration to the coldest parts of the system
Solution Approach 1:
The system dynamically switches between two operational modes: conventional vapor compression mode for warm weather and free cooling mode for cold weather. The control system automatically selects the appropriate mode based on ambient temperature conditions, allowing the system to adapt its operation to maintain reliability while optimizing energy consumption across different seasonal conditions
Solution Approach 2:
The invention changes the operational parameters of the refrigeration system by introducing a free cooling mode where the compressor is bypassed and liquid refrigerant is pumped directly through the evaporator. This parameter change allows the system to operate without compression in cold weather, eliminating the refrigerant migration problem and reducing energy consumption while maintaining cooling functionality
2Loss of energy
If a liquid refrigerant pump is used after the condenser to pump liquid refrigerant to the expansion device, then the compressor can run at lower discharge pressures and temperatures saving energy, but the system requires power-intensive mechanical cooling operation
Solution Approach 1:
The refrigeration system is segmented into two distinct operational pathways: the conventional compression cycle pathway and the free cooling pathway. The liquid refrigerant pump and control valves create a separate circulation path that bypasses the compressor, allowing the system to select the most efficient pathway based on operating conditions without requiring the entire system to operate in the more complex mechanical cooling mode
Solution Approach 2:
The liquid refrigerant pump serves multiple functions: it can operate in conjunction with the compressor during mechanical cooling mode to improve efficiency, or it can independently circulate refrigerant through the evaporator during free cooling mode. This multi-functionality allows a single component to address both energy loss reduction and system simplicity requirements across different operating scenarios
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 achieves substantial energy savings by allowing operation in free cooling mode at higher temperatures and reducing energy consumption, making it economically viable for retrofitting existing systems and improving refrigeration efficiency in cool weather.
Implementation Method 1
The condenser provides a location wherein the hot refrigerant is permitted to condense to a liquid. This results in heat transfer from the refrigerant to cooler surroundings.
Implementation Method 2
Starting with the evaporator, which is where the desired cooling effect is achieved, refrigerant evaporates, thereby carrying away the latent heat of vaporization, as it passes through the evaporator.
Implementation Method 3
refrigerant evaporates, thereby carrying away the latent heat of vaporization
Implementation Method 4
This low pressure refrigerant is then compressed by a compressor to a hot, highly pressurized gas state
Data Source
AI summary
The present invention related to cooling systems. More specifically, the present invention relates to a system for cooling one or more parts of a building and or processes comprising a compressor, a condenser having an inlet and an outlet and a plurality of condenser cooling fans, a receiver, a liquid refrigerant pump, an expansion device, an evaporator, the evaporator being surrounded by a chiller barrel having a cooled water return and a chilled water supply line, and refrigerant line means interconnecting the compressor, condenser, expansion device and evaporator in series, in a closed loop for circulating refrigerant therethrough; means for switching the cooling system between free cooling and mechanical cooling and means for actively floating the head pressure in both mechanical and free cooling modes.