Composite HVAC Hot Water Control With Adaptive Condensing Temperature
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Solution Overview
Problem
In air-conditioning and hot water supplying composite systems with a single refrigerant, the hot water supply unit struggles to stably control water delivery temperature, especially in low-temperature ranges, and experiences a degraded coefficient of performance (COP) in high-temperature ranges due to specialized refrigerant control for air-conditioning use.
Innovation Solution
The system incorporates a controller with a mode switching unit and a condensing temperature control unit that adjusts the target condensing temperature based on the heat medium temperature during the hot water supply control mode, allowing for stable temperature control and improved COP by varying the target condensing temperature according to the heat medium temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the refrigerant control is specialized for air-conditioning use in a single refrigerant system, then the system can perform heating operation and hot water supplying operation simultaneously, but the water delivery temperature control becomes unstable in low-temperature range and COP degrades in high-temperature range
Solution Approach 1:
The patent applies dynamics by making the target condensing temperature variable rather than fixed. The control unit dynamically adjusts the target condensing temperature based on the heat medium temperature, allowing the system to adapt to different operating conditions. This resolves the contradiction by enabling stable water delivery temperature control across varying temperatures while maintaining the ability to perform both heating and hot water supply operations simultaneously.
Solution Approach 2:
The patent changes the parameter of target condensing temperature from a fixed value to a variable value that depends on heat medium temperature. By establishing a relationship where target condensing temperature varies with heat medium temperature, the system achieves stable water delivery temperature control in low-temperature ranges while preventing COP degradation in high-temperature ranges, thus resolving the reliability issue while preserving versatility.
2Device complexity
If the target condensing temperature is fixed for air-conditioning optimization, then the refrigerant control is simplified, but the hot water supply unit cannot stably control water delivery temperature in low-temperature range
Solution Approach 1:
The patent changes the target condensing temperature parameter from fixed to variable based on heat medium temperature. This parameter change enables stable water delivery temperature control in low-temperature ranges without significantly increasing system complexity, as the control unit simply adjusts the target temperature based on measured heat medium temperature.
Solution Approach 2:
The patent introduces feedback by using the heat medium temperature as a basis for adjusting the target condensing temperature. The control unit continuously monitors heat medium temperature and adjusts the target condensing temperature accordingly, creating a closed-loop control system that maintains stable water delivery temperature without complex additional hardware.
3Device complexity
If the target condensing temperature is fixed for air-conditioning optimization, then the control system remains simple, but the COP degrades in high-temperature range
Solution Approach 1:
The patent optimizes energy efficiency by changing the target condensing temperature parameter to vary with heat medium temperature. In high-temperature ranges, the target condensing temperature is adjusted to prevent COP degradation, while in low-temperature ranges it ensures stable water delivery control. This parameter adaptation improves overall energy efficiency without requiring a complex control system.
Solution Approach 2:
The patent applies dynamics by making the target condensing temperature adaptive rather than static. The control system dynamically adjusts the target temperature based on real-time heat medium temperature conditions, optimizing COP in high-temperature ranges while maintaining control stability in low-temperature ranges, all through a relatively simple control mechanism.
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 enables the hot water supply unit to stably perform water delivery temperature control and enhances the system's coefficient of performance (COP) by maintaining a consistent temperature difference between the heat medium and the target condensing temperature, reducing frequent activation and improving heating capacity.
Implementation Method 1
a hot water supply unit connected to the heat source unit and including a hot water supply-side heat exchanger and a hot water supply-side expansion device
Implementation Method 2
a heat source unit including a compressor and a heat source-side heat exchanger
Implementation Method 3
configured to exchange heating energy with a heat source (air or water)
Data Source
AI summary
An air-conditioning and hot water supplying composite system includes a heat source unit and a heat source-side heat exchanger, an indoor heat source unit, a hot water supply unit connected to the heat source unit and including a hot water supply-side heat exchanger and a hot water supply-side expansion device, and a controller that controls the heat source unit. The controller includes a mode switching unit that switches a control mode of the air-conditioning and hot water supplying composite system between a hot water supply control mode, a hot water supply preheating mode, and a condensing temperature control unit. The condensing temperature control unit determines the target condensing temperature according to a temperature of a heat medium subjected to heat exchange by the hot water supply unit, in the hot water supply control mode.