Vented laundry drying having an additional heater and heat exchanger unit
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Solution Overview
Problem
Existing exhaust air laundry drying devices face efficiency drops due to fluctuations in operating conditions such as temperature and humidity, particularly when an additional heater is used, leading to overheating of the evaporator and reduced heat pump efficiency.
Innovation Solution
Incorporating a heat pump with an adjustable expansion device that adapts its flow cross-section based on operating parameters of the additional heater, such as heating power or switch-on state, to maintain high efficiency across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a heat pump is used for heat recovery, then energy efficiency is improved, but the evaporator becomes overheated when additional heater is used, causing efficiency to drop
Solution Approach 1:
The expansion device is made adjustable to dynamically adapt its flow cross-section based on the additional heater's operating state. This allows the heat pump system to maintain optimal evaporator temperature and efficiency even when the additional heater is activated and changes the thermal conditions.
Solution Approach 2:
The flow cross-section parameter of the expansion device is changed based on the additional heater's operating parameters (such as power output or on/off state). This parameter adjustment optimizes the refrigerant flow to match the changing thermal conditions, preventing evaporator overheating and maintaining system efficiency.
2Device complexity
If the flow cross-section of the expansion device is fixed, then device complexity is reduced, but the heat pump cannot adapt to changing operating conditions, reducing efficiency
Solution Approach 1:
The expansion device incorporates adjustability to dynamically adapt its flow cross-section based on operating conditions. This dynamic capability allows the heat pump to maintain high efficiency across varying thermal conditions while adding only minimal complexity to the overall system.
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 ensures that the heat pump operates efficiently even with additional heating, maintaining high efficiency by optimizing its operating point in response to changing conditions, thereby reducing energy consumption and improving drying performance.
Implementation Method 1
a heat recovery unit which is a heat pump with an evaporator (8), a condenser (9), a compressor (10) and an expansion device (11), wherein the condenser (9) is thermally coupled to the air inlet duct (3) and the evaporator (8) is thermally coupled to the air outlet duct (5)
Implementation Method 2
the evaporator (8) is thermally coupled to the air outlet duct (5)
Implementation Method 3
the condenser (9) is thermally coupled to the air inlet duct (3)
Data Source
Figure 1
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AI summary
The invention relates to a vented laundry dryer 1, comprising an air inlet duct 3, an air outlet duct 5, a heat recovery system 8-11 for transferring heat from the air outlet duct 5 to the air inlet duct 3, and an additional heater 7, wherein the heat recovery system 8-11 is a heat pump comprising an evaporator 8, a liquefier 9, a condenser 10, and a relaxation unit 11, wherein the liquefier 9 is thermally coupled to the air inlet duct 3, and the evaporator 8 is thermally coupled to the air outlet duct 5, and a relaxation property of the relaxation unit 11 can be adjusted depending on at least one parameter that is connected to an activity of the additional heater 7. A method is used to operate a vented heat dryer 1 comprising an additional heater 7 and a heat pump 8-11 having a relaxation unit 11, wherein the method comprises the following steps: (a) monitoring at least one parameter that is connected to an activity of the additional heater 7; and (b) changing a relaxation property of the relaxation unit 11 depending on the at least one parameter.