Heat transfer and hydronic systems
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Solution Overview
Problem
Existing heat transfer systems for HVAC applications face challenges such as high compressor cycling, reduced efficiency, increased electrical loads, and higher maintenance costs due to complex components and extensive refrigerant piping, which are costly and difficult to install and maintain, especially in applications with varying heating and cooling loads.
Innovation Solution
A heat transfer system comprising a refrigerant circuit with interconnected conduits, a compressor module, and expansion valves, along with fluid storage tanks and heat exchangers, that reduces refrigerant piping requirements, minimizes compressor cycling, and allows for simultaneous heating and cooling without continuous compressor operation, using alternative heat sources like boilers for heating loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing HVAC systems with multiple components are used, then heating and cooling functions are provided, but manufacturing cost, installation cost, and maintenance cost increase
Solution Approach 1:
The patent combines multiple HVAC functions (heating, cooling, dehumidification, reheat) into a single integrated system using a heat transfer fluid loop that connects a chiller, boiler, and multiple heat exchangers. This merging of functions reduces the number of separate components needed compared to traditional systems that would require separate equipment for each function.
Solution Approach 2:
The heat transfer fluid system serves multiple purposes simultaneously: it provides cooling through the chiller loop, heating through the boiler loop, dehumidification through the cooling coil, and reheat through the heating coil. This multi-functionality allows a single system to replace what would traditionally require multiple separate devices.
2Adaptability or versatility
If compressors cycle frequently to satisfy varying loads, then heating and cooling demands are met, but operating efficiency decreases and electrical load increases
Solution Approach 1:
The system pre-cools or pre-heats the heat transfer fluid in the storage tank during periods of low demand or off-peak hours. This preliminary action allows the system to meet peak loads without requiring the compressor to cycle frequently, as the pre-conditioned fluid is available to quickly respond to demand changes.
Solution Approach 2:
The heat transfer fluid acts as an intermediary between the compressor/chiller and the air handling units. By storing and transporting thermal energy through this fluid medium, the system decouples the compressor operation from the immediate heating/cooling demand, allowing the compressor to run more efficiently while the stored fluid meets variable loads.
3Stress or pressure
If refrigerant piping is extensively used, then heat transfer between refrigerant and air is achieved, but installation cost and maintenance difficulty increase
Solution Approach 1:
The patent replaces the traditional refrigerant-based mechanical heat transfer system with a hydronic (water-based) heat transfer fluid system. This substitution eliminates the need for extensive refrigerant piping, as the heat transfer fluid can be distributed through standard plumbing infrastructure, significantly reducing installation complexity and maintenance requirements while maintaining effective heat transfer through the heat exchangers.
4Reliability
If add-ons like hot gas bypass or variable frequency drives are added to compressors, then compressor cycling is reduced, but manufacturing cost and system cost increase
Solution Approach 1:
The heat transfer fluid storage tank serves as a thermal buffer that mediates between the compressor and the heating/cooling loads. This intermediary allows the compressor to operate more steadily by providing thermal mass that absorbs demand variations, reducing the need for add-ons like hot gas bypass or variable frequency drives to prevent compressor cycling.
Solution Approach 2:
The system changes the operating parameters by using a liquid heat transfer fluid with high specific heat capacity instead of relying on refrigerant phase changes. This parameter change allows for more stable thermal energy storage and transfer, reducing compressor cycling without requiring additional control devices or add-ons.
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 provides efficient heat transfer with reduced compressor operation, lower energy consumption, and lower maintenance costs by minimizing refrigerant piping and utilizing alternative heat sources, making it suitable for applications with varying loads.
Implementation Method 1
for heat exchange between the first refrigerant conduit and the second refrigerant conduit
Implementation Method 2
circulating a refrigerant through the first refrigerant conduit and the second refrigerant conduit by the refrigerant compressor module via the expansion valve for heat exchange
Implementation Method 3
circulating a refrigerant through the first refrigerant conduit and the second refrigerant conduit by the refrigerant compressor module via the expansion valve
Implementation Method 4
a first heat exchanger that includes a first heat exchange surface and the first refrigerant conduit, the first heat exchange surface being in fluid communication with the first fluid when the heat transfer system is in use, the first refrigerant conduit being positioned for heat exchange with the first heat exchange surface
Data Source
AI summary
A heat transfer system comprises a first fluid storage tank fluidly connectable to a first fluid circuit for heat exchange between the first fluid circuit and a first fluid in the fluid storage tank, a first heat exchanger positioned for heat exchange with the first fluid, and a second heat exchanger fluidly connected to the first heat exchanger via a refrigerant circuit for heat exchange with the first heat exchanger. The refrigerant circuit includes a refrigerant compressor module and an expansion valve for circulating a refrigerant therethrough for heat exchange between the first and second heat exchangers. A hydronic system is also described.