Clothes dryer and control method thereof
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Solution Overview
Problem
Heat pump clothes dryers face challenges in controlling the temperature of inlet air and discharge temperature during the drying process, leading to energy wastage, as existing solutions like subcoolers dissipate heat into the atmosphere, reducing energy utilization efficiency.
Innovation Solution
A clothes dryer with a variable speed compressor and electronic expansion valve, where the compressor's rotational speed and the expansion valve's opening are stepwise adjusted by a controller to manage heat quantity and air temperature, eliminating the need for a subcooler and optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a subcooler is used to control the temperature of inlet air of the roller, then the temperature control is achieved, but heat is dissipated into the atmosphere causing low energy utilization efficiency
Solution Approach 1:
The patent merges the subcooler with the evaporator into a single heat exchanger unit. The refrigerant flows through both the subcooler section and evaporator section within the same component, allowing heat exchange with the air circulation system to occur at both sections. This eliminates the need for a separate subcooler that would dissipate heat to the atmosphere, as the subcooling process now contributes to heating the drying air.
Solution Approach 2:
The integrated heat exchanger performs multiple functions simultaneously: it acts as both a subcooler (to control refrigerant temperature and prevent compressor damage) and an evaporator (to cool and dehumidify the air). By making the subcooler serve the dual purpose of refrigerant subcooling and air heating, the system eliminates energy waste while achieving temperature control.
2Productivity
If energy provided by refrigerant system remains constant while moisture load decreases, then the drying process continues, but the temperature of inlet air becomes increasingly higher causing materials to break
Solution Approach 1:
The patent implements dynamic control of the refrigerant system by adjusting the compressor's rotational speed based on real-time monitoring of inlet air temperature and moisture load conditions. As the drying process progresses and moisture load decreases, the controller reduces compressor speed to lower the refrigeration capacity, preventing excessive temperature rise in the inlet air and protecting the materials from thermal damage.
Solution Approach 2:
The system employs feedback control where temperature sensors continuously monitor the inlet air temperature and compressor speed. The controller receives this temperature feedback and dynamically adjusts the compressor rotational speed to maintain the inlet air temperature within a safe range, ensuring continuous drying without material damage.
3Temperature
If compressor discharge temperature increases, then the heating capability improves, but energy wastage occurs
Solution Approach 1:
The patent uses a variable speed compressor that can dynamically adjust its rotational speed to match the actual heating requirements of the drying process. By controlling compressor speed, the system optimizes the discharge temperature to provide adequate heating capability while avoiding excessive temperature rise that would lead to energy wastage. The compressor operates at lower speeds when less heating is needed, reducing energy consumption.
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 solution effectively controls the refrigerant flow, rapidly increasing air temperature to reduce energy consumption, saving energy and shortening the drying process without a subcooler, thus enhancing energy utilization efficiency.
Implementation Method 1
the air is heated by a high temperature condenser and enters into a roller to absorb moisture in the materials
Implementation Method 2
the high-humidity air is cooled and dehumidified by a low temperature evaporator, and the condensate water formed in the above process is discharged
Implementation Method 3
A heat pump system of the heat pump clothes dryer includes a compressor
Implementation Method 4
a throttling element and an evaporator
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A clothes dryer and a control method thereof are provided. The clothes dryer includes an air circulation system (A) and a refrigerant circulation system (R), the refrigerant circulation system (R) includes a compressor (1), a condenser (2), a throttling element (3) and an evaporator (4); the air circulation system (A) includes a filter device (200), an air circulation power fan (5) and a roller (6), and the refrigerant circulation system (R) does not include a subcooler; the clothes dryer further includes a controller (22), a temperature sensor or a temperature-sensing element (101, 104), and a temperature and humidity sensing element (102, 103); the controller (22) is configured to control an operation of the refrigerant circulation system (R), the operation of the clothes dryer includes a temperature rise phase and a basic drying phase, and the compressor (1) of the clothes dryer is configured to have a higher power consumption in the temperature rise phase than in the basic drying phase, to rapidly rise a temperature in the clothes dryer.