Air-Conditioning Load Control for Low-COP Humidity Stability

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Solution Overview

Problem

Existing air-conditioning systems face inefficiencies due to low coefficient of performance (COP) when operating at low loads, leading to poor temperature/humidity control and increased power consumption, especially when outside air processing devices and air-conditioning devices are not optimally coordinated.

Innovation Solution

The system dynamically adjusts the operation of outside air processing devices and air-conditioning devices based on load factors and temperature/humidity conditions, allowing for selective stopping and restarting of devices to maintain optimal COP and comfort levels, while adjusting air conditioning capacities to prevent overload states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the operation of the air-conditioning device is stopped when the load factor is low, then the heating capacity of the outside air processing device is increased, but the indoor temperature/humidity environment may become worse when the outside air processing device has poor followability

Engineering Contradiction:
Improveheating capacityVSAvoidindoor temperature/humidity environment
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control device continuously monitors the indoor temperature and humidity, and uses this feedback to dynamically adjust the operation of both the outside air processing device and air-conditioning device. This ensures that the indoor environment is maintained within acceptable ranges while optimizing heating capacity and energy efficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the operational status of the air-conditioning device based on real-time load factors, indoor environmental conditions, and the heating capacity of the outside air processing device. This dynamic control allows the system to adapt to changing conditions and prevent indoor environment deterioration.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If the load is distributed between devices to minimize power consumption, then individual indoor units repeatedly start and stop at low load, but this causes discontinuous change in air conditioning capacity and reduces COP

Engineering Contradiction:
Improvepower consumptionVSAvoidair conditioning capacity
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The control device prevents frequent start-stop operations by maintaining continuous operation of at least one device (outside air processing device or air-conditioning device) even when load factors are low. This ensures continuous air conditioning capacity and avoids the energy inefficiency associated with frequent cycling.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The control device acts as an intermediary that coordinates the operation of multiple devices, ensuring that when one device operates at low load, the other device is also operated to provide continuous air conditioning capacity and prevent discontinuous changes.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If the chiller is operated at low load, then the COP is very low, but stopping the chiller causes discontinuous operation and reduces heating capacity

Engineering Contradiction:
ImproveCOPVSAvoidheating capacity
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The system merges the heating capacities of the outside air processing device and air-conditioning device, allowing them to work together to compensate for the low COP of the chiller at low load. This combination ensures sufficient heating capacity while managing energy efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control device changes operational parameters (such as supply air temperature, airflow rate, and device operation status) to optimize the overall system performance, balancing the low COP of the chiller at low load with the need for sufficient heating capacity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3943825B1Air-conditioning system
Publication Date: 2024.05.08 DAIKIN INDUSTRIES LTD
  • EP3943825B1 patent drawingFigure 1

AI summary

In an air-conditioning system (100) including an outside air processing device (10) and an air-conditioning device (20), an operation of either one of the outside air processing device (10) or the air-conditioning device (20) is stopped if a temperature/humidity state that is at least either the temperature or humidity of air in a target space (SP1, SP2) is within a predetermined range and if the load factor of at least one of the outside air processing device (10) or the air-conditioning device (20) is below a predetermined lower limit.