Supplemental cooling system load control using random start of first defrost cycle
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Solution Overview
Problem
Centralized refrigeration systems in aircraft galleys face premature failure due to simultaneous defrost cycles causing thermal and mechanical stress, and existing solutions complicate integration and maintenance.
Innovation Solution
Implementing a method where each cooling unit randomly selects a start time for its first defrost cycle within a predetermined range, followed by periodic defrost cycles, allowing continuous coolant flow and avoiding synchronized shutdowns, thus reducing wear and tear on the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software logic is modified to desynchronize defrost cycles, then compressor continuous operation is improved, but system complexity and integration difficulty increase
Solution Approach 1:
Each cooling unit independently determines its own defrost cycle timing through a simple random number generation process. The units do not require centralized coordination or complex communication protocols - each unit autonomously selects a random start time for its first defrost cycle and then follows periodic intervals, dramatically simplifying system architecture while achieving the goal of desynchronized operation.
2Temperature
If cooling units undergo repeated startup and shutdown to prevent overheating, then compressor temperature is controlled, but mechanical stress and wear increase causing premature failure
Solution Approach 1:
The system ensures continuous coolant flow to the compressor by staggered defrost timing, eliminating the need for repeated compressor shutdowns and restarts. The randomization of first defrost cycle start times across multiple cooling units creates an overlapping pattern where coolant flow is maintained continuously, preventing thermal stress and mechanical wear from cyclic operation.
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 approach ensures robust operation by maintaining a baseline coolant flow, preventing unnecessary start and stop cycles, simplifying integration and maintenance, and ensuring food safety temperatures without requiring software modifications.
Implementation Method 1
By using a fan or air convection, the heat exchanger may absorb heat inside the cooling units, thereby reducing the inside ambient temperature to a desired food safe temperature.
Implementation Method 2
a vapor cycle system comprising of a compressor, condenser, expansion valve, evaporator, and refrigerant is often utilized to chill liquid coolant
Data Source
AI summary
Methods, apparatus, and systems for load control for cooling systems are provided. Coolant flows through a plurality of cooling units in a cooling system. The coolant flow is halted for each cooling unit that is undergoing a defrost cycle. Each cooling unit is configured to start a first defrost cycle at a random time within a predetermined time range after the cooling unit is started or powered on. After the first random start defrost cycle, a regular periodic defrost cycle may be maintained. Thus, the cooling units may be powered on simultaneously while still providing desynchronized defrost cycles, enabling the cooling system to maintain adequate coolant flow and heat load to avoid deleterious stop and restart cycles.