Cold Storage Thermal Control for Off-Peak Pre-Cooling
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Solution Overview
Problem
Cold storage facilities face inefficiencies in refrigeration management due to varying heat intrusion rates and energy costs, leading to high operational costs and energy wastage, as traditional systems are often toggled on and off intermittently, consuming more energy during peak demand hours.
Innovation Solution
Implementing a system that models cold storage facilities as thermal batteries, allowing them to be pre-cooled during off-peak hours and then warmed during peak hours, using a control system with temperature sensors and energy cost models to optimize refrigeration schedules, reducing power usage and shifting energy consumption to non-peak times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If refrigeration systems are operated continuously to maintain setpoint temperature, then temperature stability is improved, but energy consumption increases
Solution Approach 1:
The system performs preliminary cooling actions during off-peak hours when energy costs are lower, pre-cooling the facility below the setpoint temperature. This stored thermal energy is then utilized during peak hours to maintain temperature stability without continuous refrigeration operation, thereby reducing overall energy consumption while preserving temperature stability.
Solution Approach 2:
Instead of continuous operation, the refrigeration system operates periodically based on energy cost variations and thermal model predictions. The system alternates between active cooling phases and passive maintenance phases, using the thermal mass of the facility to maintain temperature during off-periods, thus reducing total energy consumption while maintaining adequate temperature stability.
2Stability of the object's composition
If refrigeration systems are operated during peak demand hours to maintain temperature, then temperature control is improved, but operational costs increase
Solution Approach 1:
The system performs preliminary cooling during off-peak hours when energy costs are lower, storing thermal energy in the facility's thermal mass. This allows the system to maintain temperature control during expensive peak hours without operating the refrigeration system, thereby reducing operational costs while preserving temperature control through the stored thermal energy.
Solution Approach 2:
The system uses a thermal model that continuously monitors facility conditions, outdoor temperature, solar load, and door usage patterns to predict future thermal behavior. This feedback mechanism enables the system to optimize the timing and extent of pre-cooling operations, ensuring adequate temperature control during peak hours while minimizing energy consumption and operational costs.
3Use of energy by moving object
If refrigeration systems are turned off during low demand periods to reduce energy consumption, then energy efficiency is improved, but temperature stability deteriorates
Solution Approach 1:
The system performs preliminary cooling during off-peak periods, storing thermal energy in the facility's thermal mass below the setpoint temperature. When the refrigeration system is turned off during low demand periods, this stored thermal energy maintains temperature stability without requiring active cooling, thus improving energy efficiency while preserving temperature stability through the pre-stored thermal buffer.
4Use of energy by stationary object
If pre-cooling is performed during off-peak hours to shift energy demand, then energy cost is reduced, but equipment runtime increases
Solution Approach 1:
The system performs pre-cooling during off-peak hours when energy costs are lower, utilizing the thermal mass of the facility to store the removed heat energy. By optimizing the pre-cooling duration and intensity based on the thermal model and predicted heat intrusion, the system achieves adequate temperature maintenance during peak hours with minimal additional equipment runtime, thus reducing overall energy costs while limiting excessive equipment 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 reduces operational costs by minimizing peak energy consumption, extends equipment lifespan, and helps balance energy demand, thereby lowering overall energy wastage and environmental impact.
Implementation Method 1
Heat removal from a cold storage facility generally requires the consumption of power (e.g., electricity to drive refrigeration compressors)
Implementation Method 2
models of cold storage facilities, such as refrigerated warehouses, can be generated and used to determine the cooling strategies for more efficiently selecting times when and temperatures to which the cold storage facilities are cooled. Cold storage facilities can be modeled as thermal batteries that are capable of absorbing and storing thermal energy that can then be released over time
Implementation Method 3
Heat intrusion within a cold storage facility can come from many different sources, such as the environment (e.g., ambient air temperature, solar radiation)
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, a method for time shifting when a cold storage facility is cooled that includes determining a thermal model of a cold storage facility, obtaining an energy cost model that describes a schedule of variable energy costs over a predetermined period of time in the future, determining an operational schedule for at least a portion of a refrigeration system based on the thermal model, the energy cost model, and a maximum allowed temperature, and powering on the portion the refrigeration system based on the operational schedule, cooling, by the powered portion of the refrigeration system to a temperature below the maximum allowed temperature, reducing power usage of the powered portion of the refrigeration system based on the operational schedule, and permitting the facility to be warmed by ambient temperatures toward the maximum allowed temperature.