Heat Medium Flow Control in Air Conditioning to Cut Pump Energy
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Solution Overview
Problem
Existing air-conditioning apparatuses for buildings face issues such as refrigerant leakage, high energy consumption due to long heat medium circulation paths, complex construction requirements, and inefficiencies in refrigerant flow management, leading to increased costs and noise.
Innovation Solution
An air-conditioning apparatus with a refrigerant cycle and a heat medium cycle, featuring a heat medium flow control device, temperature sensors, and a controller that adjusts the flow rate and pump operation to optimize heat medium temperature and reduce energy consumption, while minimizing refrigerant circulation near indoor units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant is circulated to indoor units, then heating and cooling functions are achieved, but refrigerant leakage to indoor space occurs
Solution Approach 1:
The patent introduces a heat medium (water or antifreeze solution) as an intermediary substance to transfer thermal energy between the outdoor heat source unit and indoor units. This heat medium circulates through dedicated pipes without mixing with the refrigerant, thereby eliminating refrigerant leakage risks to indoor spaces while maintaining effective heating and cooling functions. The heat medium acts as a safe mediator that decouples the refrigerant circulation system from indoor environments.
2Reliability
If heat medium circulation path is made long to avoid refrigerant in indoor units, then safety is improved, but energy consumption increases due to high conveyance power
Solution Approach 1:
The patent implements dynamic control of the heat medium circulation system by equipping each indoor unit with a flow control valve that adjusts heat medium flow rate based on actual heating or cooling demands. Additionally, the outdoor heat source unit dynamically adjusts its operation capacity according to the aggregate demand of all indoor units. This dynamic adjustment optimizes the balance between safety (maintaining separate heat medium circulation) and energy efficiency (reducing unnecessary conveyance power consumption).
Solution Approach 2:
The system changes operational parameters such as heat medium flow rate, pump speed, and heat exchanger capacity based on real-time conditions. By varying these parameters dynamically rather than maintaining fixed high-capacity operation, the system achieves both safety through separated circulation and energy efficiency through optimized parameter selection.
3Adaptability or versatility
If four water pipes are arranged to connect outdoor unit to each indoor unit for simultaneous cooling and heating, then versatility is improved, but construction complexity increases
Solution Approach 1:
The patent implements a universal two-pipe connection system where the same pair of pipes carries heat medium for both heating and cooling operations. By using flow direction control valves and a heat source side four-way valve, the system achieves multi-functionality (both heating and cooling) through a single piping infrastructure, eliminating the need for separate four-pipe installations for each function.
4Temperature
If heat exchanger is disposed near each indoor unit, then heat transfer efficiency is improved, but refrigerant leakage risk near indoor space cannot be eliminated
Solution Approach 1:
The patent places a heat exchanger near each indoor unit but uses it to transfer heat between the heat medium (in pipes) and the indoor air, rather than having refrigerant直接接触 indoor air. The heat medium serves as an intermediary that absorbs or releases heat in the heat exchanger without posing leakage risks, thereby maintaining high heat transfer efficiency while eliminating refrigerant leakage concerns in indoor spaces.
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 reduces energy consumption, enhances safety by preventing refrigerant leakage, simplifies construction, and allows for efficient energy use by optimizing heat medium flow and temperature control.
Implementation Method 1
a heat exchanger related to heat medium which exchanges heat between the refrigerant and the heat medium
Implementation Method 2
pumps which circulate the heat medium
Implementation Method 3
use side heat exchangers which exchange heat between the heat medium and indoor air
Data Source
Figure 1~2
Figure 3
Figure 3A
AI summary
To provide an air-conditioning apparatus capable of achieving energy saving, a pump control of controlling the operating capacity of a pump 21 is performed such that an opening degree of a heat medium flow control device 25, controlled by a heat-medium-flow-control-device control, approaches a target opening degree, and a refrigeration cycle of a refrigerant circuit is controlled such that the temperature of a heat medium, whose flow rate is controlled by the heat-medium-flow-control-device control and the pump control, approaches a target temperature.