Control system and control method for frostless, multivariable coupling, and heat pump-based hot blast stove
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Solution Overview
Problem
Current heat pump-based hot blast stoves face issues such as frost formation in winter, reduced efficiency due to high condensing temperatures in summer, inadequate air temperature increase, low operating efficiency due to pressure differences, and shortened compressor life from high load operations, which hinder effective grain drying and energy savings.
Innovation Solution
A control system and method for a frostless, multivariable coupling and heat pump-based hot blast stove, featuring a configuration of multiple heat exchangers, heat pump units, and a temperature detector that enables gradient heat-circulation preheating and frostless modes to manage temperature zones and prevent frost formation, utilizing a solution circulation pipeline and solution heat exchanger to optimize heat exchange and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional reverse defrosting method is adopted, then frost on evaporator can be removed, but the unit has to be stopped resulting in low drying efficiency
Solution Approach 1:
The patent converts the harmful frost accumulation on the evaporator into a beneficial pre-cooling resource. The frost layer is intentionally allowed to form and then utilized as a cold storage medium to pre-cool the air before it enters the evaporator, reducing the evaporator's cooling load and preventing frost formation while maintaining continuous operation.
Solution Approach 2:
The patent introduces an intermediary pre-cooling heat exchanger that mediates between the ambient air and the evaporator. This intermediary device uses the frost layer as a heat exchange medium to pre-cool the air, thereby protecting the evaporator from frost accumulation while allowing the main drying system to operate continuously without interruption.
2Use of energy by moving object
If heat pump equipment is used, then energy saving and emission reduction are achieved, but the high condensing temperature in summer leads to severe heat waste and reduced operating efficiency
Solution Approach 1:
The patent applies preliminary cooling action by using the pre-cooling heat exchanger to cool the air before it enters the evaporator. This preliminary action reduces the temperature difference between the ambient air and the evaporator, thereby reducing the condensing temperature and the associated heat waste during the drying process.
Solution Approach 2:
The patent changes the temperature parameter of the air entering the evaporator by using the pre-cooling heat exchanger. This parameter change reduces the condensing temperature of the heat pump system, thereby reducing the heat waste in the condenser and improving the overall energy efficiency of the system.
3Device complexity
If fresh air flows through the heat exchanger at the same temperature, then the heat exchange process is simple, but the temperature of the fresh air cannot be increased to a required temperature
Solution Approach 1:
The patent segments the heat exchange process into two distinct stages: pre-cooling in the pre-cooling heat exchanger and then heating in the evaporator. This segmentation allows the system to efficiently achieve the required temperature increase by utilizing the cold frost layer first, followed by the heating process, thereby simplifying the overall heat exchange process while achieving the desired temperature.
4Reliability
If the system operates in winter with low condenser temperature, then condensation effect is good, but the high-low pressure difference is small resulting in low circulation power and operating efficiency
Solution Approach 1:
The patent applies preliminary cooling to the air before it enters the evaporator, which maintains a more favorable temperature difference across the heat exchanger. This preliminary action helps maintain adequate pressure difference and circulation power in the winter operating conditions while ensuring good condensation effect.
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 system achieves efficient grain drying by forming preheating, low, medium, and high temperature zones, ensuring frostless operation in winter and reducing energy waste, thereby enhancing the overall efficiency and extending compressor life without the need for additional heat pump units.
Implementation Method 1
heat pump-based hot blast stove
Implementation Method 2
the high condensing temperature of the system
Implementation Method 3
the evaporating temperature decrease
Implementation Method 4
after fresh air is subjected to heat exchange in the condenser
Data Source
AI summary
A control system and method for a frostless, multivariable coupling and heat pump-based hot blast stove are used for grain drying. A first heat exchanger, a second heat exchanger, a main solution pool, corresponding pipelines, and a temperature detector are configured in the control system. A first heat pump unit, a second heat pump unit and a third heat pump unit are formed. A preheating zone, a low temperature zone, a medium temperature zone and a high temperature zone are sequentially formed on an air supply pipeline from a fresh air inlet to a fresh air outlet. A frostless operation procedure is provided. Through the configuration, the control system and method for a frostless, multivariable coupling and heat pump-based hot blast stove can implement heat supply in a gradient heat-circulation preheating mode and a gradient heat-circulation frostless mode.