Dual-Mode Air Conditioning Control for Rapid Indoor Load Response
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Solution Overview
Problem
In air conditioning systems using water or brine as a heat medium, there is a delay in responding to indoor load variations due to the distance between the heat source and the point of use, leading to compromised comfort and inefficient temperature adjustments.
Innovation Solution
A controller that operates in two modes: the first mode fixes the flow rate adjustment valve's degree of opening and varies the compressor's operation frequency, while the second mode adjusts the valve's opening based on required air conditioning performance, allowing for immediate adaptation to indoor load changes by optimizing the flow rate and compressor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If water or brine is used as heat medium and delivered through pipes from heat source to indoor units, then refrigerant usage is reduced and environmental performance is improved, but response time to indoor load variations increases and comfort deteriorates
Solution Approach 1:
The control device predicts future indoor load variations based on historical data and environmental conditions, and pre-adjusts the water temperature or flow rate before the actual load change occurs. This preliminary action compensates for the thermal inertia and pipe transport delay, enabling the system to respond more quickly to indoor load variations while maintaining the environmental benefits of using water as heat medium
Solution Approach 2:
The control device continuously monitors indoor temperature, outdoor conditions, and system performance, using this feedback to dynamically adjust water temperature and flow rate. This closed-loop control compensates for the delay inherent in water-based heat delivery, improving response time while maintaining energy efficiency and reducing refrigerant usage
2Productivity
If water temperature from water heater/cooler is varied to match indoor load changes, then air conditioning performance is improved, but time delay in temperature adjustment propagates through pipes and compromises comfort
Solution Approach 1:
The control device anticipates indoor load changes by analyzing historical data, outdoor temperature trends, and occupancy patterns. It pre-adjusts the water temperature in the heat medium circuit before the actual indoor load change occurs, compensating for the thermal inertia and pipe transport time. This allows the system to maintain high air conditioning performance while eliminating the comfort-deteriorating delay
Solution Approach 2:
The control device dynamically adjusts both water temperature and flow rate based on real-time conditions and predicted load variations. By making the system dynamically responsive rather than statically adjusted, it overcomes the inherent time delay in water-based heat delivery, enabling rapid adaptation to indoor load changes while maintaining energy efficiency
3Loss of time
If flow rate of heat medium is increased to reduce transport delay, then response time is improved, but energy consumption increases and system efficiency deteriorates
Solution Approach 1:
The control device dynamically adjusts the flow rate of heat medium based on actual indoor load conditions and predicted temperature requirements. Instead of maintaining a constantly high flow rate, it optimizes the flow in real-time, increasing it only when and where needed to reduce transport delay, and reducing it during stable conditions to minimize pump energy consumption and maintain system efficiency
Solution Approach 2:
The control device changes multiple parameters simultaneously - water temperature, flow rate, and timing of adjustments - to achieve optimal performance. By coordinating these parameter changes, it reduces heat medium transport time without proportionally increasing pump energy consumption, as the system learns to make precise, targeted adjustments rather than continuous high-energy operation
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 solution enables air conditioning performance to immediately follow indoor load variations, enhancing comfort and efficiency by rapidly adjusting to changing temperature demands.
Implementation Method 1
a compressor configured to compress a first heat medium
Implementation Method 2
a first heat exchanger configured to exchange heat between the first heat medium and outdoor air
Implementation Method 3
a second heat exchanger configured to exchange heat between the first heat medium and a second heat medium
Implementation Method 4
a third heat exchanger configured to exchange heat between the second heat medium and indoor air
Implementation Method 5
a pump configured to circulate the second heat medium between the third heat exchanger and the second heat exchanger
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An object of the present invention is to cause air conditioning performance to immediately follow variation in indoor load in an indirect air conditioning system using water or brine. An air conditioning apparatus (1) has a first mode and a second mode as operation modes. In the first mode, a degree of opening of a first flow rate adjustment valve (33) is fixed to a first degree of opening smaller than 100% and greater than 0%, and an operation frequency of a compressor (11) is varied in accordance with air conditioning performance required of a third heat exchanger (31). In the second mode, the degree of opening of the first flow rate adjustment valve (33) is varied in accordance with air conditioning performance required of the third heat exchanger (31). When a difference between the air conditioning performance required of the third heat exchanger (31) and air conditioning performance offered by the third heat exchanger (31) becomes greater than a determination value, the operation mode is changed from the first mode to the second mode.