Water Heat Exchanger Flow Control for Simultaneous Heating and Cooling
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Solution Overview
Problem
Conventional refrigeration cycle apparatuses face inefficiencies in energy saving during simultaneous cooling and heating operations due to unnecessary water flow rates and temperature detection errors, leading to increased pump power consumption and potential freezing of water heat exchangers.
Innovation Solution
A refrigeration cycle apparatus that adjusts the water flow rate to the water heat exchanger based on the ratio of the absolute difference between the total operation capacities of use-side heat exchangers performing heating and cooling operations, ensuring the flow rate is minimized and optimized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water flow rate is increased to ensure adequate cooling of the water heat exchanger, then the heat exchanger is prevented from freezing, but pump power consumption increases and energy saving is reduced
Solution Approach 1:
The patent applies dynamics by making the water flow rate adjustable and variable based on operating conditions. The control unit dynamically changes the water flow rate to the water heat exchanger according to the absolute difference between heating and cooling operation capacities, transitioning from fixed flow rate to variable flow rate operation. This resolves the contradiction by allowing the system to use minimum necessary flow rate (saving energy) while maintaining freezing prevention through dynamic adjustment.
Solution Approach 2:
The patent changes the parameter of water flow rate from a fixed value to a variable value determined by the formula involving the absolute difference between heating and cooling capacities. By changing this parameter dynamically based on operational demands, the system achieves both energy saving (reduced pump power) and reliability (freezing prevention) across different operating conditions.
2Use of energy by moving object
If water flow rate is reduced to save energy, then pump power consumption decreases, but the water heat exchanger may freeze when temperature detection errors occur
Solution Approach 1:
The patent applies preliminary action by calculating and setting an appropriate water flow rate in advance based on the absolute difference between heating and cooling operation capacities before freezing can occur. The control unit proactively adjusts the flow rate according to the thermal balance requirements, preventing the water heat exchanger from reaching freezing conditions while minimizing energy consumption.
Solution Approach 2:
The patent implements feedback by continuously monitoring heating and cooling operation capacities and using this information to adjust the water flow rate to the water heat exchanger. The control unit receives feedback on the thermal loads and dynamically modifies the flow rate to maintain safe operating temperatures while optimizing energy efficiency.
3Ease of operation
If conventional control methods are used to adjust water volume based on compressor frequency and fan rotation speed, then the system operates smoothly, but water is supplied at higher than necessary flow rates during simultaneous cooling and heating
Solution Approach 1:
The patent transitions from static control (fixed water flow rate) to dynamic control (variable water flow rate) by making the water flow rate dependent on the absolute difference between heating and cooling capacities. This dynamic adjustment ensures smooth system operation while eliminating energy waste from excessive water flow during simultaneous cooling and heating operations.
Solution Approach 2:
The patent changes the control parameter from compressor frequency and fan rotation speed to the absolute difference between heating and cooling operation capacities. This parameter change enables more precise matching of water flow rate to actual thermal needs, reducing energy waste while maintaining ease of operation through automated control.
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 reduces waste water and improves energy-saving performance by ensuring the water flow rate is at a required minimum level, thereby reducing pump power consumption and preventing freezing of the water heat exchanger.
Implementation Method 1
an outdoor side water heat exchanger exchanging heat between refrigerant and cooling water
Implementation Method 2
a water circuit connecting a pump
Data Source
AI summary
A flow rate of circulating water to a water heat exchanger is determined by multiplying, by a rated water flow rate, a ratio of an absolute value of a difference between a total operation capacity of each of indoor side heat exchangers serving as a heating load and a total operation capacity of each of indoor side heat exchangers serving as a cooling load to a total operation capacity of the water heat exchanger.