Heat Pump Water Heater Fan Control for High-Side Pressure
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Solution Overview
Problem
Conventional heat pump water heaters experience excessive pressure increases in the high pressure side of the refrigerant circuit due to rising water temperatures, which can lead to operational limitations.
Innovation Solution
A heat pump water heater design featuring a refrigerant circuit with a compressor, radiator, and evaporator connected by a refrigerant pipe, a fan for air blowing towards the evaporator, a water storage tank with a temperature sensor, and a controller that lowers the fan's rotation speed as water temperature rises, reducing evaporating capability and thus preventing excessive pressure increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the water temperature in the storage tank increases to improve heating efficiency, then the heat exchange amount increases, but the pressure in the high pressure side of the refrigerant circuit increases excessively
Solution Approach 1:
The fan rotation speed is dynamically adjusted based on water temperature conditions. When the water temperature exceeds a predetermined threshold, the controller reduces the fan rotation speed to lower the evaporating capability and suppress pressure increase in the high pressure side of the refrigerant circuit
Solution Approach 2:
The system changes the operational parameters of the fan based on temperature conditions. By adjusting the fan rotation speed parameter in response to water temperature changes, the system maintains heating efficiency while preventing excessive pressure buildup in the refrigerant circuit
2Productivity
If the refrigerant pipe is wound around the periphery of the tank to improve heat exchange, then the heating efficiency increases, but the pressure control capability is reduced when water temperature rises
Solution Approach 1:
The controller continuously monitors the water temperature in the storage tank and uses this feedback to adjust the fan rotation speed. When the temperature exceeds the predetermined threshold, the controller reduces fan speed to maintain pressure within acceptable ranges, creating a closed-loop control system that balances heat exchange efficiency with pressure control
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
The solution effectively prevents excessive pressure increases in the high pressure side of the refrigerant circuit, ensuring stable operation and efficient heating by optimizing fan speed and refrigerant flow based on water and ambient temperatures.
Implementation Method 1
a fan for blowing air toward the evaporator
Implementation Method 2
a radiator, a decompressor, and an evaporator are connected in a loop by a refrigerant pipe
Implementation Method 3
a fan for blowing air toward the evaporator
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A heat pump water heater according to the present disclosure includes a refrigerant circuit in which a compressor, a radiator, a decompressor, and an evaporator are connected in a loop by a refrigerant pipe, a fan for blowing air toward the evaporator, a water storage tank for storing hot water, a tank temperature sensor provided in the water storage tank, and a controller for controlling an operation of at least the fan. The radiator is configured such that the refrigerant pipe is wound around a periphery of the water storage tank. As compared to when a temperature of the hot water in the water storage tank is low, a rotation speed of the fan is lower when the temperature of the hot water in the water storage tank is high.