Two-Circuit Room Temperature Control With Safe Secondary Fluid
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Solution Overview
Problem
Existing refrigeration technologies face challenges in using environmentally friendly refrigerants due to their high global warming potential and flammability, which limits their safe use in enclosed spaces, necessitating a solution that minimizes refrigerant usage and avoids flammable substances within these spaces.
Innovation Solution
A temperature control system utilizing a primary heat pump circuit with a natural refrigerant outside the room, coupled with a secondary circuit using a non-flammable secondary fluid for heat transfer, where the secondary fluid undergoes a phase change to transport heat or cold into the room, minimizing the risk of flammable substances entering the enclosed space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flammable refrigerants are avoided in enclosed spaces, then safety is improved, but refrigeration efficiency may deteriorate
Solution Approach 1:
The refrigeration system is segmented into two circuits: the primary circuit outside the room uses efficient but flammable natural refrigerants, while the secondary circuit inside the room uses safe non-flammable fluids. This segmentation maintains high refrigeration efficiency in the primary circuit while ensuring safety in the enclosed space.
Solution Approach 2:
A heat exchanger acts as an intermediary between the primary and secondary circuits. It transfers the cooling effect generated by the natural refrigerant in the primary circuit to the non-flammable secondary fluid, which then distributes the cold inside the room. This intermediary mechanism preserves refrigeration efficiency while eliminating flammability risks from the enclosed space.
2Object-affected harmful factors
If a secondary circuit with non-flammable fluid is introduced, then flammability risk is reduced, but device complexity increases
Solution Approach 1:
The system is segmented into two independent circuits: a primary heat pump circuit and a secondary distribution circuit. Each circuit uses appropriately selected fluids for its specific function and location, reducing flammability risk while maintaining manageable complexity through clear functional separation.
Solution Approach 2:
A heat exchanger serves as an intermediary that couples the primary and secondary circuits thermally while keeping them fluidically independent. This intermediary component enables the system to achieve safety through fluid separation without requiring complex control mechanisms or additional safety systems, thus limiting the increase in device complexity.
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 allows for efficient and safe temperature control in enclosed spaces by using hydrocarbons as natural refrigerants while ensuring minimal refrigerant usage and avoiding flammability risks, leveraging microchannel technology and thermosyphon principles for compact and energy-efficient operation.
Implementation Method 1
the secondary fluid undergoes a phase change to transport heat or cold into the room
Implementation Method 2
the secondary fluid undergoes a phase change
Implementation Method 3
the secondary fluid undergoes a phase change
Implementation Method 4
a secondary circuit that is thermally coupled to the evaporator or the condenser via a heat exchanger
Implementation Method 5
the physical effect of the heat of vaporization when changing the state of matter from liquid to gaseous, or from gaseous to liquid
Implementation Method 6
In the downstream second heat exchanger 4 (evaporator, or heat source of the process) the refrigerant evaporates at a low temperature while absorbing heat (evaporative cooling)
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
The invention relates to a device for controlling the temperature of a space (5) to be temperature-controlled, the space having a space boundary (20) that separates the space to be temperature-controlled from the surroundings (21), the device comprising: a primary heat pump circuit having an evaporator (4), a condenser (2), a compressor (1) and an expansion element (3), the primary heat pump circuit having a natural, e.g. flammable, primary working fluid, and the evaporator (4), the condenser (2), the compressor (1) and the expansion element (3) being located outside the space to be temperature-controlled; and a secondary circuit, which is thermally coupled to the evaporator (4) or to the condenser (2) via a heat exchanger (7) and is fluidically decoupled and has a temperature-control element (14), which is located in the space (5) to be temperature-controlled and is connected to the heat exchanger (7) via a line arrangement (15a, 15b) that has a secondary fluid differing from the primary working fluid, the line arrangement (15a, 15b) penetrating the space boundary (20).