Thermal energy system and method of operation
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Solution Overview
Problem
Commercial refrigeration systems using carbon dioxide as a refrigerant face inefficiencies due to its low critical temperature, leading to transcritical operation and reliance on less effective sensible heat transfer, resulting in reduced cooling capacity and increased energy input.
Innovation Solution
A thermal energy system that utilizes a dual heat sink configuration, with a remote heat sink and ambient air heat sink, allowing for selective alteration of heat exchanger order in the fluid loop to optimize condensing temperature and minimize energy input, using a controller to manage fluid flow and maximize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If carbon dioxide refrigerant is used in refrigeration systems, then environmental performance is improved, but system efficiency deteriorates due to low critical temperature causing transcritical operation
Solution Approach 1:
The system dynamically switches between subcritical and transcritical operating modes based on ambient conditions. The heat exchanger configuration is dynamically adjusted to maintain optimal condensing temperature, allowing the system to adapt to varying environmental conditions and maintain high efficiency while using CO2 refrigerant
Solution Approach 2:
The system changes the operating parameters of the CO2 refrigerant by controlling the condensing temperature through selective heat exchanger configuration. By adjusting whether the system operates in subcritical or transcritical mode, the refrigerant's thermal properties are optimized for different ambient conditions, resolving the efficiency problem while maintaining environmental benefits
2Adaptability or versatility
If transcritical operation is used with CO2 refrigerant, then system adaptability to ambient conditions is improved, but cooling capacity deteriorates due to reliance on sensible heat transfer
Solution Approach 1:
The system dynamically selects between subcritical and transcritical modes based on ambient temperature conditions. When ambient conditions favor latent heat transfer, the system operates in subcritical mode to maximize cooling capacity. When ambient conditions require adaptability, transcritical mode is selected, optimizing the balance between adaptability and cooling capacity
Solution Approach 2:
The system utilizes phase transitions of CO2 refrigerant by operating in subcritical mode when possible, where condensation occurs and latent heat transfer maximizes cooling capacity. The system leverages the phase change from gas to liquid in the condenser to achieve high cooling capacity while maintaining adaptability through the ability to switch to transcritical mode when necessary
3Reliability
If constant thermometric control is implemented, then operational reliability is improved, but energy consumption increases
Solution Approach 1:
The system uses ambient environmental conditions to automatically determine the optimal operating mode. The control system monitors ambient temperature and automatically selects between subcritical and transcritical operation, reducing the need for constant active thermometric control while maintaining operational reliability and reducing energy consumption
Solution Approach 2:
The system implements feedback control by monitoring ambient conditions and adjusting the heat exchanger configuration accordingly. This feedback mechanism maintains operational reliability by ensuring optimal condensing temperature is achieved while minimizing energy consumption through intelligent, condition-based control rather than constant thermometric regulation
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 enhances the refrigeration cycle's efficiency by reducing compressor work, increasing evaporating capacity, and improving the coefficient of performance (COP) by utilizing both sensible and latent heat transfer effectively, even under transcritical conditions.
Implementation Method 1
a first heat exchanger system adapted to be coupled to a first remote heat sink containing a working fluid and a second heat exchanger system adapted to be coupled to ambient air as a second heat sink
Implementation Method 2
the liquid refrigerant absorbs heat as it evaporates in the evaporator
Implementation Method 3
the compressed gas is reduced in temperature to enable condensation of the refrigerant
Implementation Method 4
The gaseous refrigerant is compressed by the compressor, as represented by line b to c. This causes an increase in gas pressure and temperature
Implementation Method 5
The liquid is then reduced in pressure by the compressor via an expansion device represented by line e to a
Data Source
AI summary
A thermal energy system comprising a first thermal system having a heating demand, and a heat source connection system coupled to the first thermal system, the heat source connection system being adapted to provide selective connection to a plurality of heat sources for heating the first thermal system, the heat source connection system comprising a first heat exchanger system coupled to a first remote heat source containing a working fluid and a second heat exchanger system adapted to be coupled to ambient air as a second heat source, a fluid loop interconnecting the first thermal system, the first heat exchanger system and the second heat exchanger system, at least one mechanism for selectively altering the order of the first heat exchanger system and the second heat exchanger system in relation to a fluid flow direction around the fluid loop, and a controller for actuating the at least one mechanism.