Air conditioner controlling method
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Solution Overview
Problem
Current air-conditioning systems for medium to large buildings face challenges in energy efficiency, particularly in neutral seasons where outdoor air temperature variations lead to increased consumption of chilled and hot water, as they are designed to maintain constant total heat-exchange efficiency and outdoor-air volume percentage across seasons, resulting in inefficient energy use.
Innovation Solution
An air conditioner controlling method that dynamically adjusts total heat-exchange efficiency and outdoor-air volume percentage using linear functions to maintain a specified supply-air temperature, allowing for stepped levels of outdoor-air volume percentage and setting retention ranges to minimize the use of chilled and hot water across seasons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If total heat-exchange efficiency and outdoor-air volume percentage are constantly maintained at specified values across all seasons, then the air conditioner can operate with simple control settings, but energy consumption increases in neutral seasons due to unnecessary use of chilled and hot water
Solution Approach 1:
The patent applies dynamics by making the total heat-exchange efficiency and outdoor-air volume percentage adjustable rather than fixed. The control method dynamically changes these parameters based on outdoor air temperature ranges, allowing the system to adapt to seasonal variations. In neutral seasons, the system adjusts parameters to minimize chilled and hot water usage, while in heating and cooling seasons, it maintains appropriate settings for those seasons, thereby reducing overall energy consumption without compromising operational simplicity
Solution Approach 2:
The patent implements parameter changes by modifying the total heat-exchange efficiency and outdoor-air volume percentage according to outdoor air temperature ranges. The control method divides the year into different temperature ranges and assigns optimal parameter values for each range, enabling the system to transition from constant parameter operation to variable parameter operation that responds to environmental conditions, thus reducing energy waste in neutral seasons
2Loss of energy
If outdoor-air volume percentage is increased to utilize comfortable outdoor air in neutral seasons, then energy consumption for heating and cooling decreases, but the supply-air temperature cannot be constantly maintained at specified values
Solution Approach 1:
The patent resolves this contradiction through dynamic parameter adjustment. By making the total heat-exchange efficiency adjustable based on outdoor air temperature, the system can compensate for variations in mixed air temperature caused by changing outdoor-air volume percentages. This dynamic compensation mechanism allows the system to maintain stable supply-air temperature while utilizing higher outdoor-air volume percentages in neutral seasons, thereby achieving both energy savings and temperature stability
Solution Approach 2:
The control method employs feedback by continuously monitoring outdoor air temperature and adjusting the total heat-exchange efficiency and outdoor-air volume percentage accordingly. This closed-loop control ensures that the supply-air temperature remains at specified values while optimizing energy consumption. The system uses temperature feedback to determine the appropriate operating mode and parameter settings, balancing the competing requirements of energy efficiency and temperature stability
3Stability of the object's composition
If chilled water and hot water supply is frequently regulated to maintain supply-air temperature in neutral seasons, then the supply-air temperature can be maintained, but energy consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing optimal parameter settings for different outdoor air temperature ranges. Instead of frequently regulating chilled and hot water supply in response to temperature deviations, the system proactively adjusts the total heat-exchange efficiency and outdoor-air volume percentage based on predicted temperature conditions. This preventive approach eliminates the need for frequent water regulation, maintaining supply-air temperature stability while minimizing energy consumption
Solution Approach 2:
The system implements self-service by using the total heat exchanger to automatically adjust the temperature of outdoor air based on pre-determined parameter settings for different temperature ranges. The system serves itself by leveraging the thermal properties of outdoor air and the heat exchanger to maintain supply-air temperature without requiring frequent intervention from chilled or hot water systems, thereby reducing energy consumption associated with water regulation
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 method reduces energy consumption by optimizing the use of chilled and hot water throughout the year, achieving energy savings by adjusting settings based on outdoor-air temperature ranges to maintain the desired supply-air temperature with minimal water usage.
Implementation Method 1
The ventilation system makes a total heat exchange between outdoor air and exhaust air to regulate the temperature of the outdoor air
Implementation Method 2
an air conditioner which cools or heats the air inside of the building by taking air from the outdoor and regulating the air temperature using chilled water or hot water
Data Source
AI summary
An air conditioner controlling method includes: deciding on a supply-air temperature Ts and a return-air temperature Tr as specified design values; deciding that the total heat-exchange efficiency η is zero; selecting two or more stepped levels of the outdoor-air volume percentage α; deriving a linear function which expresses a relation between an outdoor-air temperature To and a mixed-air temperature Tm for each level of the outdoor-air volume percentage α by using the return-air temperature Tr and the total heat-exchange efficiency η; and deciding on the range where the mixed-air temperature Tm is lower than the supply-air temperature Ts for each of the linear functions and the range where the mixed-air temperature Tm in each linear function comes closest to the supply-air temperature Ts as compared with the mixed-air temperatures Tm in the other linear functions.