Freeze Free HVAC Evaporator Coil Technologies

A frost-free air source heat pump device that eliminates the conventional frost formation issues associated with low outdoor temperatures. The device features a unique evaporator design with strategically positioned cooling fins, a support frame at the bottom of the box, and a partition separating the evaporator from the lower wall. A heating component is positioned in the cavity between the partition and the lower wall, allowing the device to maintain optimal performance even in low outdoor temperatures while preventing frost formation.

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A ventilation system that enables continuous operation of air conditioning systems while preventing frost formation in evaporator coils. The system employs a dual-heat-exchanger configuration where the evaporator coil is connected to the condenser coil. When frost forms on the evaporator coil, the system automatically switches to the condenser coil as the evaporator coil is defrosted, maintaining continuous refrigerant flow. This approach prevents compressor shutdown during frost formation, ensuring efficient operation of both the air conditioning system and the ventilation system.

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Cooling device for refrigerated cabinets and deep-frozen cabinets in households and grocery stores that optimizes defrosting through real-time monitoring of evaporator icing. The device incorporates sensors for temperature, pressure, and compressor operation, enabling continuous detection of evaporator icing levels based on actual operating conditions. This integrated monitoring system enables adaptive defrost control that starts when icing exceeds predetermined thresholds, ensuring continuous defrosting even during periods of low icing activity.

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Preventing evaporator coil freeze in heating, ventilation and air conditioning (HVAC) systems during re-heat dehumidification mode. The method involves monitoring the saturated suction temperature (SST) of the refrigerant and adjusting the compressor speed based on the SST. If the SST falls below a minimum temperature, the compressor speed is decreased to reduce the risk of evaporator coil freeze. If the SST rises above the minimum temperature, the compressor speed is increased to maintain performance.

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Preventing evaporator coil freeze in HVAC systems through dynamic modulation of discharge air temperature (DAT) setpoint. The system monitors the saturated suction temperature (SST) of the evaporator coil and adjusts the DAT setpoint based on whether the SST is below a predetermined threshold. When the SST falls below this threshold, the DAT setpoint is increased. Conversely, when the SST rises above this threshold, the DAT setpoint is decreased. This controlled modulation enables precise temperature regulation while preventing frost formation in the evaporator coil.

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Building control system for HVAC systems that optimizes liquid temperature monitoring and prevention of coil freezing. The system uses a temperature sensor positioned at the inlet of the coil to measure liquid temperature, comparing it to a freeze prevention threshold. When the sensor indicates safe liquid temperature, the system automatically activates freeze prevention actions, such as valve control or airflow management. The system employs a heat transfer model to predict freezing points and calculates optimal liquid flow rates based on measured temperature. If the sensor indicates unsafe liquid temperature, the system switches to using air temperature measurements instead. This approach enables precise temperature monitoring while preventing coil freezing through intelligent temperature feedback.

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Air source heat pump system that eliminates frost formation in evaporator while maintaining efficient heating and cooling performance. The system employs a unique four-way valve configuration that allows continuous operation during both heating and cooling cycles. The valve enables controlled flow of refrigerant between the evaporator, condenser, and intermediate heat exchanger, maintaining optimal heat transfer conditions regardless of temperature. This design eliminates the need for defrosting procedures, which can compromise system performance and increase energy consumption. The system operates with a single compressor and condenser, eliminating the complexities and inefficiencies associated with traditional defrosting methods.

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Liquid desiccant air conditioning systems using antifreeze-free heat transfer fluids that employ system design rather than additive-based freeze protection. The systems maintain performance in freezing conditions by incorporating design modifications that enable freeze protection through system operation rather than component-specific additives. The system includes a liquid desiccant conditioner, regenerator, and heat exchanger, with the conditioner and regenerator operating in a controlled manner to maintain the heat transfer fluid's integrity during freezing conditions. The system's design enables freeze protection without the need for Glycol, while maintaining high cooling and heating performance.

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An air conditioner that prevents frost buildup on the indoor heat exchanger and dripping when defrosting. The air conditioner has a control unit that freezes the indoor heat exchanger using the evaporator function. But before freezing, it checks conditions to avoid issues like dripping. Conditions for freezing include: indoor temperature >= first threshold, difference between indoor and evaporator temps <= third threshold (after cooling/dehumidifying), outdoor humidity <= fourth threshold, or cooling/dehumidifying with significant temp decrease. This ensures the indoor air isn't overly humid or the temps aren't too close to freeze before defrosting.

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Controlling HVAC system operation to prevent negative performance due to freeze conditions through a novel system architecture. The system employs a controller that monitors refrigerant flow through the evaporator coil and discharge air temperature in the duct. When the coil temperature drops below a predetermined threshold, the controller detects freeze risk and initiates specific fan operation strategies to prevent ice formation. The system balances fan speed to maintain optimal air circulation while also implementing controlled compressor operation to prevent compressor failure. This approach enables continuous operation while mitigating the performance-critical issues associated with evaporator coil freezing.

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Low-temperature air source heat pump with a flasher circuit for defrosting in cold climates. The heat pump has a flash evaporator connected to a user heat exchanger, air-cooled evaporator, and vapor-liquid separator. A frequency conversion compressor supplies supplementary air to the flash evaporator. Defrosting is achieved by using the compressor to increase the refrigerant temperature in the flash evaporator, causing the ice to melt and vaporize. This prevents frosting on the outdoor heat exchanger.

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System for automatically controlling air conditioning systems to prevent ice formation in indoor evaporator units. The system monitors the temperature of the evaporator coil and compares it to a predetermined threshold. When the coil temperature falls below the threshold, the system automatically switches off the air conditioning system to prevent ice formation. The system can be integrated into existing air conditioning systems and provides real-time monitoring and control through sensors and a dedicated processor.

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A low-ring temperature air source heat pump system that eliminates the need for an additional economizer and defrosting system while maintaining efficient operation in low-ambient temperatures. The system integrates the economizer and defrosting components into the evaporator design, with the economizer positioned at the bottom of the finned evaporator and the defrosting system integrated into the evaporator's heat exchanger. This configuration enables continuous operation in low-ambient temperatures without the need for separate defrosting and economizer units.

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Air conditioner with enhanced indoor heat exchanger cleaning through a novel evaporator control mechanism. The system employs an integrated evaporator that serves as both the outdoor and indoor heat exchanger in the refrigeration cycle. The evaporator's operation is controlled by the compressor and first expansion valve, with a unique feature of terminating the freezing process after a predetermined time period (tc1) when the indoor heat exchanger is in a frozen state. This controlled freezing enables effective water removal from the indoor heat exchanger while preventing water freezing in the drain system.

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Air conditioner with enhanced dew prevention through smart expansion valve control. The system calculates dew point based on measured temperatures of the indoor heat exchanger, expansion valve, humidity sensor, and evaporator coil. When the indoor temperature drops below dew point, the control unit automatically increases the expansion valve opening degree, optimizing condensation prevention and energy efficiency.

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Air conditioner with integrated moisture management system that prevents water droplets from the indoor fan surface during freezing. The system controls the compressor and expansion valve to operate the condenser and evaporator as an indoor heat exchanger, with the fan rotating in reverse during freezing. This prevents water droplets from accumulating on the fan surface.

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A dry wind anti-frost system for air source heat pumps that eliminates the conventional solution spraying mechanism. The system employs a rotary dehumidifier to provide dry air to the heat pump's evaporator, rather than relying on a spray system. The dehumidifier uses lithium chloride as a desiccant to absorb moisture from the air, which is then utilized to regenerate the heat pump's desiccant. This approach eliminates the issues associated with spray systems, including increased heat transfer resistance and moisture absorption limitations. The system integrates with the heat pump's existing components, such as centrifugal fans, rotary wheel dehumidifier, and regeneration air heater, to provide a reliable and efficient anti-frost solution.

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A control method for an air harmony system that optimizes indoor air quality through precise temperature management. The system employs a refrigerant circuit with a compressor, condenser, expansion valve, and evaporator to maintain a consistent indoor environment. The control system monitors the dew point temperature of the indoor air supply and adjusts the refrigerant pressure to maintain a target dew point. This temperature control enables optimal humidity management while maintaining the evaporator's optimal operating conditions. The system achieves this through a unique dew point-based temperature control strategy that balances the refrigerant's latent heat load with the indoor air's humidity requirements.

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An air conditioning system that utilizes a specially designed evaporator coil to remove airborne contaminants from the indoor air, eliminating the need for traditional filters. The system incorporates a unique coil design that traps debris on its fins, preventing airborne pollutants from entering the indoor air stream. By capturing these contaminants at the coil surface, the system achieves virtually 100% clean indoor air quality, eliminating the need for conventional filters. This approach significantly reduces hospital-acquired infections and medical expenses compared to conventional air conditioning systems.

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Vehicle cabin exhaust air heat recovery system that enables efficient heat recovery from the rear cabin air conditioning system, particularly when the rear evaporator is located in the passenger cabin. The system utilizes the rear evaporator's ability to operate at temperatures above freezing points, while the front cabin evaporator operates in a conventional cooling mode. The system achieves this by employing a specialized expansion valve configuration that allows refrigerant to flow through the rear evaporator during cooling mode operation, while maintaining the front evaporator in its cooling mode. This configuration enables the rear evaporator to recover heat without freezing, while the front evaporator continues to operate normally.

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