Thermal management for solar-powered off-grid refrigeration
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Solution Overview
Problem
Existing solar-powered off-grid refrigeration systems lack efficient thermal management and control strategies to maintain optimal storage conditions and battery state-of-charge, especially during periods of low solar insolation.
Innovation Solution
A thermal and environmental control system that includes solar photovoltaic panels, a battery pack, and a cloud-based computing system. The system uses model-predictive controls to adjust thermal setpoints, battery state-of-charge limits, and environmental conditions based on weather data and solar incidence, optimizing battery usage and reducing energy demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solar photovoltaic panels are used to power cooling equipment, then the system operates off-grid with renewable energy, but the system cannot maintain cooling during periods of low solar insolation
Solution Approach 1:
The system performs preliminary action by charging the battery pack during periods of high solar insolation before the cooling equipment is needed during low insolation periods. The control system proactively manages battery charging when solar power is abundant, ensuring energy is stored in advance for future cooling demands.
Solution Approach 2:
The battery pack serves as an intermediary energy storage device between the solar photovoltaic panels and the cooling equipment. It decouples the intermittent solar power supply from the continuous cooling requirement, allowing the system to maintain reliable operation during periods of low solar insolation.
2Reliability
If battery energy storage is used to power cooling equipment during low solar insolation, then the system can maintain cooling continuously, but the battery state-of-charge may drop below acceptable limits
Solution Approach 1:
The control system implements feedback by continuously monitoring the battery state-of-charge and adjusting cooling equipment operation accordingly. When the battery charge level approaches the minimum threshold, the system reduces cooling demand or adjusts thermal setpoints to preserve battery charge, ensuring the battery remains within acceptable operating limits while maintaining continuous cooling.
Solution Approach 2:
The system dynamically adjusts thermal setpoints and cooling equipment operation based on real-time battery state-of-charge conditions. The controllable thermal storage allows the system to shift cooling loads temporally, reducing cooling demand when battery charge is low and maximizing cooling when battery charge is high, thereby maintaining both continuous cooling and acceptable battery charge levels.
3Quantity of substance
If thermal setpoints are adjusted to conserve battery charge, then battery state-of-charge is maintained above minimum limits, but the quality and life of stored goods may deteriorate
Solution Approach 1:
The system combines controllable thermal storage media with conventional cooling to create a composite thermal management system. This allows the system to maintain optimal temperatures for goods quality while using the thermal storage to buffer against battery charge limitations, ensuring both goods preservation and acceptable battery operation.
Solution Approach 2:
The system carefully manages parameter changes in thermal setpoints within narrow ranges that preserve goods quality. Rather than making large temperature adjustments that would compromise goods, the system makes subtle, controlled parameter changes that maintain quality while still conserving battery charge, and uses thermal storage to bridge temporary deficits.
4Productivity
If cloud-based computing system with model-predictive control is implemented, then thermal management is optimized based on weather forecasts, but the system complexity increases
Solution Approach 1:
The system replaces complex real-time control mechanics with model-predictive control based on weather forecasts. Instead of continuously adjusting controls in response to real-time conditions, the cloud-based system uses predictive models to pre-determine optimal control strategies, simplifying the real-time control architecture while maintaining high thermal management efficiency.
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 effectively maintains optimal storage conditions and battery state-of-charge, ensuring reliable off-grid refrigeration even during periods of low solar insolation, thereby minimizing the loss of storage life of cold-storage goods.
Implementation Method 1
An array of one or more solar photovoltaic panels produces electricity
Implementation Method 2
a battery pack in operable connection with the array of solar photovoltaic panel(s) stores the electricity produced by the one or more solar photovoltaic panels
Implementation Method 3
cooling equipment regulates temperature in a cold storage space of the off-grid refrigerated facility
Data Source
AI summary
In embodiments of a thermal and environmental control system an off-grid cold-storage facility has solar photovoltaic panels for producing electricity. A battery is in operable connection with the solar photovoltaic panels and configured to store the electricity produced by the solar photovoltaic panels. Cooling equipment is in operable connection to the battery and configured to regulate the temperature of the off-grid storage facility. Ventilation equipment is in operable connection to the battery to regulate air humidity and gas concentrations. A computer processor is provided at the off-grid storage facility and is in operable connection with the cooling equipment. The computer processor is configured to provide a regulating signal to the cooling equipment for optimizing battery usage, thermal setpoint, and environmental conditions. A cloud-based computing system is in operable communication to weather data and in operable communication to the computer processor. The cloud-based computing system is configured to compute optimized battery usage, thermal setpoint, and environmental conditions of the off-grid storage facility based on the weather data.