Methods for reducing energy consumption in a heating, ventilation and air conditioning (HVAC) system
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Solution Overview
Problem
HVAC systems face high energy consumption due to inefficiencies in transferring cooling effects from refrigerant to chilled water and then to air, leading to increased running costs and energy usage, especially in large area and district cooling applications.
Innovation Solution
Implementing a HVAC system with in-flow and out-flow air temperature sensors to control compressors based on predetermined temperature conditions, turning them off when thermal comfort is met in high heat load areas and turning them on when necessary, to balance thermodynamic and hydraulic work, thereby reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressors operate continuously to maintain cooling in HVAC systems, then thermal comfort is ensured, but energy consumption increases significantly
Solution Approach 1:
The compressors are operated periodically rather than continuously. The control method monitors return air temperatures and supply air temperatures over predetermined time periods, turning compressors on and off based on whether temperature thresholds are met for the required duration. This periodic operation reduces energy consumption while ensuring thermal comfort is maintained when needed.
Solution Approach 2:
The system uses temperature sensors to continuously monitor return air temperatures and supply air temperatures, feeding this information back to the control processor. Based on this feedback, the control processor determines whether compressors should be turned on or off, creating a closed-loop control system that optimizes energy usage while maintaining thermal comfort.
2Use of energy by moving object
If compressors are turned off to reduce energy consumption, then energy savings are achieved, but cooling performance may deteriorate
Solution Approach 1:
The system monitors temperature conditions in advance and predicts when compressors will need to be turned on or off. By checking whether return air temperatures have been below the predetermined temperature for a predetermined time period and whether supply air temperatures have reached the minimum supply air temperature, the system makes proactive decisions about compressor operation, preventing both premature shutdown and unnecessary operation.
Solution Approach 2:
The compressor operation is made dynamic rather than static. The control processor continuously evaluates temperature conditions and adjusts compressor operation accordingly. The system adapts to changing thermal conditions in real-time, turning compressors on when cooling is needed and off when thermal comfort is achieved, optimizing both energy consumption and cooling performance.
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 significantly reduces energy consumption and running costs by optimizing compressor usage, achieving energy savings of 18.6%-32% compared to conventional systems in tested sites.
Implementation Method 1
a plurality of in-flow air temperature sensors that measure return air temperatures at inlets of fan coil units (FCUs) located in rooms of the building, a plurality of out-flow air temperature sensors that measure supply air temperatures at outlets of the FCUs
Implementation Method 2
a plurality of compressors and condensers that generate high pressure refrigerant to cool and then circulate by means of pumps a refrigeration conduction media through pipes
Implementation Method 3
the cooling effect from the refrigerant is first transferred to the chilled water
Implementation Method 4
circulate by means of pumps a refrigeration conduction media through pipes used to cool circulating air through FCUs
Data Source
AI summary
A heating, ventilation and air conditioning system (200) reduces energy consumption in a building (202) by turning on and off all compressors (212, 214, 216). The HVAC system (200) includes a plurality of in-flow air temperature sensors (232, 234, 236) and out-flow air temperature sensors (242, 244, 246) that respectively measure return air temperatures at inlets and supply air temperatures at outlets of fan coil units (222, 224, 226) located in rooms (203, 205, 207) of the building (202). The HVAC system (200) turns on and off all the compressor (212, 214, 216) based on the return air temperatures and the supply air temperatures.