In an embodiment, a method of preventing evaporator coil freeze in a heating, ventilation and air conditioning (HVAC) system includes determining a reference saturated suction temperate (SST) via a sensor disposed in relation to an evaporator coil in the HVAC system, where the HVAC system is operating in reheat dehumidification mode. The method also includes determining whether the reference SST is below a minimum SST threshold. The method also includes, responsive to a determination that the reference SST is below the minimum SST threshold, determining a decreased compressor speed. The method also includes modulating a variable-speed compressor in the HVAC system in correspondence to the decreased compressor speed.

In an embodiment, a method of preventing evaporator coil freeze in a heating, ventilation and air conditioning (HVAC) system includes determining a reference saturated suction temperate (SST) via a sensor disposed in relation to an evaporator coil in the HVAC system, where the HVAC system is operating in reheat dehumidification mode. The method also includes determining whether the reference SST is below a minimum SST threshold. The method also includes, responsive to a determination that the reference SST is below the minimum SST threshold, determining a decreased compressor speed. The method also includes modulating a variable-speed compressor in the HVAC system in correspondence to the decreased compressor speed.

A dedicated outside air-conditioning system (DOAS) that may automatically generate variable subcooling refrigerant delivered to the evaporator; and modulate hot discharge gas to reduce the relative humidity of the discharge air from the DOAS. The DOAS may include fluid control valves configured to regulate delivery of the refrigerant in order to seamlessly flex between maximum latent capacity (minimum discharge dewpoint) and maximum sensible capacity (minimum leaving air discharge dry bulb temperature) to match load and/or ventilation air requirements.

A dedicated outside air-conditioning system (DOAS) that may automatically generate variable subcooling refrigerant delivered to the evaporator; and modulate hot discharge gas to reduce the relative humidity of the discharge air from the DOAS. The DOAS may include fluid control valves configured to regulate delivery of the refrigerant in order to seamlessly flex between maximum latent capacity (minimum discharge dewpoint) and maximum sensible capacity (minimum leaving air discharge dry bulb temperature) to match load and/or ventilation air requirements.

A method for anti-condensation at an air conditioner radiation terminal in the present invention belongs to the field of air conditioning devices. When a dehumidifying heat exchanger in a fresh air ventilator performs refrigeration to dehumidify, heat of condensation generated in the dehumidification in the fresh air ventilator is used for providing a heat source for the indoor radiation terminals, thereby preventing condensation and reducing consumption of electric energy. There further is a method for anti-condensation, based on the foregoing method for anti-condensation, at radiation terminals of an air conditioning system in a multi-room space in the present invention, the heat of condensation in dehumidification in a fresh air ventilator is effectively used, to prevent condensation indoors, especially in a plurality of rooms, and gain a good effect of saving energy.

A method for anti-condensation at an air conditioner radiation terminal in the present invention belongs to the field of air conditioning devices. When a dehumidifying heat exchanger in a fresh air ventilator performs refrigeration to dehumidify, heat of condensation generated in the dehumidification in the fresh air ventilator is used for providing a heat source for the indoor radiation terminals, thereby preventing condensation and reducing consumption of electric energy. There further is a method for anti-condensation, based on the foregoing method for anti-condensation, at radiation terminals of an air conditioning system in a multi-room space in the present invention, the heat of condensation in dehumidification in a fresh air ventilator is effectively used, to prevent condensation indoors, especially in a plurality of rooms, and gain a good effect of saving energy.

An improved HVAC system and method for simultaneously controlling the temperature and humidity of an indoor space while providing high quantities of outdoor air is described herein. The HVAC system of the present invention utilizes a heating source positioned in the supply passageway between an energy recovery wheel and a dehumidification wheel in order to control the temperature and humidity of air supplied to the indoor space while preventing frost build-up on the energy recover wheel. By positioning a heating source between the energy recovery wheel and a dehumidification wheel, the system is able to prevent frost accumulation on the energy recovery wheel during winter operation while also increasing the relative humidity of the supply air.

A dedicated outdoor air system and method that is capable of operating over a broader spectrum of conditions. The HVAC system of the present invention utilizes a heating means positioned within the return air passageway in order to optimize the regeneration of the desiccant wheel and energy recovery device. By positioning a heating means upstream of the regeneration side of the desiccant wheel, the system is capable of providing supply air having low dew points to the enclosed space while still providing improved energy efficiency over conventional HVAC systems.

A dedicated outdoor air system and method that is capable of operating over a broader spectrum of conditions. The HVAC system of the present invention utilizes a heating means positioned within the return air passageway in order to optimize the regeneration of the desiccant wheel and energy recovery device. By positioning a heating means upstream of the regeneration side of the desiccant wheel, the system is capable of providing supply air having low dew points to the enclosed space while still providing improved energy efficiency over conventional HVAC systems.

A process gas treatment device for a process gas for treating a process material in a process apparatus and a method for treating process gas for the treatment of a process material in a process apparatus during a drying phase and a cooling phase.