Thermoelectric Chiller Control for Stable Temperature Setpoints
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Solution Overview
Problem
Chiller systems face challenges in achieving tight system stability when compressors are controlled in an on and off mode, leading to inefficiencies, particularly when using electrical heaters for temperature control, as they require prolonged compressor operation and frequent start-stop cycles, which increase wear and reduce efficiency.
Innovation Solution
Incorporating a thermoelectric module into the chiller system, connected in either the coolant or refrigerant loop, to provide additional heating or cooling capacity, allowing the compressor to run continuously and maintaining stable temperature set points, thereby reducing the need for frequent start-stop cycles and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electrical heater is added in the coolant loop to provide improved temperature control, then temperature control precision is improved, but energy efficiency deteriorates
Solution Approach 1:
The patent introduces a thermoelectric module as an intermediary device in the coolant loop that can both heat and cool the coolant. This replaces the purely resistive electrical heater with a device that transfers heat from the environment rather than generating it through resistance, significantly improving energy efficiency while maintaining precise temperature control capability
Solution Approach 2:
The thermoelectric module allows the system to change the heating/cooling parameter dynamically by adjusting the electrical current direction and magnitude. This enables precise temperature control while consuming far less energy than resistive heating, as the module can operate in heating mode, cooling mode, or idle state based on real-time temperature requirements
2Device complexity
If the compressor is controlled in an on and off mode, then device complexity is reduced, but system stability deteriorates
Solution Approach 1:
The thermoelectric module acts as an intermediary that handles fine temperature adjustments while the compressor operates in simple on/off mode. This mediator absorbs the complexity of continuous temperature regulation, allowing the compressor to maintain a simple control strategy while the overall system achieves tight temperature stability through the combined action of compressor cooling and thermoelectric modulation
Solution Approach 2:
The system uses partial action by having the compressor provide coarse cooling in on/off cycles while the thermoelectric module provides the remaining partial adjustment needed to reach and maintain the precise setpoint temperature. This division of labor maintains system stability without requiring complex compressor control
3Duration of action of stationary object
If the compressor runs continuously to avoid frequent start-stop cycles, then compressor lifespan is extended, but energy efficiency deteriorates
Solution Approach 1:
The thermoelectric module serves as a mediator that takes over the task of fine temperature regulation, allowing the compressor to cycle on and off rather than running continuously. This eliminates the energy waste of continuous compressor operation while preventing excessive start-stop cycles, as the thermoelectric module can maintain temperature during compressor off periods
Solution Approach 2:
The system implements periodic compressor operation combined with continuous thermoelectric modulation. The compressor runs in periodic cycles to provide bulk cooling, while the thermoelectric module operates continuously at low power to maintain precise temperature, achieving both energy efficiency and compressor longevity
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 thermoelectric module improves system efficiency, extends compressor lifespan, and provides precise temperature control, reducing cooldown time and system size while maintaining stable temperatures, even when compressor capacity is less than maximum demand.
Implementation Method 1
a thermoelectric module connected in the coolant loop and adapted to transfer heat into and/or out of the coolant fluid
Implementation Method 2
a heat transfer component connected in the refrigerant loop to receive the condensed refrigerant fluid from the condenser, and connected in the coolant loop to transfer heat from the coolant fluid to the condensed refrigerant fluid
Implementation Method 3
a compressor connected in the refrigerant loop to compress the refrigerant fluid
Implementation Method 4
a condenser connected in the refrigerant loop to receive the compressed refrigerant fluid from the compressor and to condense the compressed refrigerant fluid
Data Source
AI summary
According to various aspects, exemplary embodiments are disclosed of chiller systems including thermoelectric modules, and corresponding control methods. In an exemplary embodiment, a compressor chiller system generally includes a refrigerant loop having a refrigerant fluid, a compressor connected in the refrigerant loop to compress the refrigerant fluid, and a condenser connected in the refrigerant loop to receive the compressed refrigerant fluid from the compressor and to condense the compressed refrigerant fluid. The system also includes a heat transfer component connected in the refrigerant loop to receive the condensed refrigerant fluid from the condenser, and a coolant loop having a coolant fluid. The heat transfer component is connected in the coolant loop to transfer heat from the coolant fluid to the condensed refrigerant fluid. The system further includes a thermoelectric module connected in the coolant loop. The thermoelectric module is adapted to transfer heat into and/or out of the coolant fluid.