Refrigeration and heating system
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Solution Overview
Problem
At high ambient temperatures, refrigeration systems face inefficiency as they reject a significant portion of heat as waste, limiting their ability to effectively cool the refrigerant and provide heating capacity.
Innovation Solution
A refrigeration and heating system with a coupling heat exchanger and a gas cooler bypass line allows for selective routing of refrigerant flow, enabling mixing of cooled and bypassed refrigerant streams to optimize heat transfer and reduce waste heat rejection, particularly using transcritical CO2 operation to adjust pressure and temperature for efficient heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a gas cooler is activated to cool the refrigerant at high ambient temperatures, then the refrigerant cooling capability is improved, but approximately 1/3 of the heat is rejected as waste heat to the environment
Solution Approach 1:
The refrigerant flow is segmented into two separate streams: one stream passes through the gas cooler to be cooled, while the other stream bypasses the gas cooler. These segmented streams are then mixed downstream to achieve the desired temperature while maximizing heat utilization.
Solution Approach 2:
The system changes the flow rate parameters of the two refrigerant streams dynamically. By regulating the flow rates of refrigerant through the gas cooler versus bypassing it, the system can adjust the mixing temperature downstream to match heating requirements, thereby changing the thermal parameters to eliminate waste heat rejection.
2Reliability
If the gas cooler is activated to handle high ambient temperatures, then the refrigeration system can operate, but the heating capacity is reduced due to waste heat rejection
Solution Approach 1:
The system merges the refrigeration function and heating function by combining two refrigerant streams with different thermal states. The cold stream from the gas cooler and the warm stream from the bypass line are mixed to provide both cooling capability (through the gas cooler operation) and heating capability (by directing the mixed refrigerant to the coupling heat exchanger).
Solution Approach 2:
The gas cooler bypass valve assembly provides multi-functionality by enabling the system to simultaneously achieve refrigerant cooling (through partial flow through the gas cooler) and heat recovery (through the bypass stream and coupling heat exchanger). This single component allows the system to adapt to high ambient temperature conditions while maintaining heating capacity.
3Loss of energy
If the refrigerant temperature is reduced to a reasonable limit, then more heat capacity can be used for heating, but the temperature range for efficient operation is limited
Solution Approach 1:
The system dynamically adjusts the flow distribution between the gas cooler and bypass line based on operating conditions. The gas cooler bypass valve assembly continuously regulates the split of refrigerant flow to adapt to varying ambient temperatures and heating demands, enabling efficient operation across a wide temperature range rather than at a fixed operating point.
Solution Approach 2:
By changing the flow rate parameters of the two streams and their mixing ratio, the system can achieve different outlet temperatures from the gas cooler while still utilizing maximum heat capacity for heating. This parameter adjustment extends the efficient operating temperature range without sacrificing energy utilization.
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 configuration extends the temperature range for efficient operation, allowing stable system performance at higher water inlet temperatures and minimizing heat loss to ambient air, thereby enhancing overall energy efficiency.
Implementation Method 1
a coupling heat exchanger which is configured for transferring heat from the circulating refrigerant to the circulating heating fluid
Implementation Method 2
a gas cooler is activated for further cooling down the refrigerant
Implementation Method 3
at least one expansion device
Implementation Method 4
at least one evaporator
Data Source
AI summary
A refrigeration and heating system includes a refrigeration circuit which includes in the direction of flow of a circulating refrigerant: at least one compressor; a refrigeration circuit side of a coupling heat exchanger; at least one gas cooler; at least one gas cooler bypass line and at least one gas cooler bypass valve assembly allowing to bypass the at least one gas cooler; at least one expansion device and at least one evaporator. The refrigeration and heating system includes a heating circuit which includes in the direction of flow of a circulating heating fluid: a heating circuit side of the coupling heat exchanger and at least one heating device.