Refrigeration Load Shifting Through Off-Peak Thermal Storage
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Solution Overview
Problem
Energy consumption peaks during extreme temperatures cause strain on the electric grid, leading to frequent outages and high energy costs, necessitating a method to shift refrigeration device operation to non-peak hours.
Innovation Solution
A method that regulates refrigeration device operation by storing thermal energy during non-peak hours, allowing the device to operate during non-peak hours and remain offline during peak hours, utilizing an internal clock, time durations, and temperature settings to manage compressor and fan operation, ensuring safe temperatures and reducing grid load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigeration device operates continuously to maintain safe temperatures, then food safety is ensured, but energy consumption increases during peak demand periods
Solution Approach 1:
The system pre-cools the refrigeration space during non-peak hours before the scheduled shutdown, storing thermal energy in the form of cold mass. This preliminary action allows the device to maintain safe temperatures during peak hours without active operation, resolving the contradiction between continuous operation for safety and reduced operation for energy savings
Solution Approach 2:
The system dynamically adjusts the target temperature parameter based on the timing relative to peak demand periods. During pre-cool mode, it maintains a lower target temperature to store more thermal energy, while during shutdown mode, it allows the temperature to rise within safe limits. This parameter adjustment enables the system to balance food safety with energy reduction
2Use of energy by moving object
If the refrigeration device shuts down during peak hours to reduce energy consumption, then energy costs are reduced, but temperature control capability is lost
Solution Approach 1:
Before the scheduled shutdown during peak hours, the system performs pre-cooling to store thermal energy in the refrigeration space and contents. This preliminary action ensures that when the device shuts down, the stored cold mass maintains safe temperatures, thereby preserving temperature control capability without energy consumption during peak periods
Solution Approach 2:
The system continuously monitors the actual temperature during shutdown and compares it against the maximum safe temperature threshold. When the temperature approaches this threshold, the system receives feedback and adjusts by extending the pre-cool duration or reducing the shutdown period in subsequent cycles, ensuring temperature control reliability while maintaining energy savings
3Loss of energy
If the refrigeration device operates during non-peak hours to store thermal energy, then grid load is reduced during peak hours, but device complexity increases
Solution Approach 1:
The system implements a scheduled pre-cool operation during non-peak hours based on predetermined timing parameters. This preliminary action stores thermal energy in the refrigeration space, enabling the device to shut down during peak hours and reduce grid load. The use of scheduled operations rather than continuous complex control simplifies the overall system while achieving energy load shifting
Solution Approach 2:
The system operates in periodic cycles alternating between pre-cool mode and shutdown mode, synchronized with the utility company's peak demand schedule. This periodic operation pattern simplifies control logic compared to continuous variable control, reducing device complexity while effectively shifting load away from peak periods
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
Effectively reduces power grid load during peak hours by shifting refrigeration device operation to non-peak hours, preventing excessive temperature rises and maintaining safe conditions, thereby lowering energy costs and reducing the risk of outages.
Implementation Method 1
The present invention is a method of regulating the operation of a refrigeration device in order to store thermal energy during non-peak hours for use during peak hours
Implementation Method 2
During the peak energy demand period, the refrigeration unit is disabled and the refrigeration unit temperature is allowed to steadily rise over the peak energy demand period
Data Source
AI summary
The present invention is a method of regulating a refrigeration device by storing thermal energy during non-peak hours for use during peak hours in order to shift refrigeration device operation to non-peak hours. In a first iteration, a real-time temperature of the refrigeration device is cooled to a target temperature over a first time duration. The refrigeration device compressor and fan are disabled over a second time duration and the real-time temperature is allowed to slowly rise, never exceeding an established maximum temperature. The real-time temperature is periodically monitored over the first time duration and the second time duration and adjustments are made for a subsequent iteration if the target temperature is reached before the end of the first time duration, if the target temperature is not reached during the first time duration, and if the maximum temperature is reached during the second time duration.