AirCycler

The AirCycler is a programmable ventilation controller for Central Fan Supply Ventilation designs. When you are providing fresh air for a house through a fresh air supply duct connected from the outside to the return plenum of the HVAC system it is essential to have the air handler operate on a scheduled cycle to provide fresh air for the house. This programmable timer is connected to the thermostat connection of the air handler to monitor the run time of the air handler and when needed turn on the air handler to meet the fresh air requirements of the house. The timer will take advantage of free distribution of ventilation air during thermostat driven heating or cooling operation and provides periodic whole house mixing and ventilation air distribution during periods when thermostat driven heating or cooling operation does not meet the programmed fresh air demand.

Applications

Ventilation Systems

Outside Air Duct Into The Central System Air Handler Return Plenum

Ventilation systems that provide ventilation air through a duct that extends from outdoors to the return plenum of a central air handler only supply ventilation air when the fan is operating. Rather than operating the central system fan continuously, which can waste energy and can also lead to moisture related problems in humid climates, the recycling control can be set to periodically distribute ventilation air during stagnant periods when there is no call to circulate air for purposes of heating or cooling.

An economical and effective ventilation system, using the AirCycler, would be a 6" to an 8" diameter insulated duct (depending on the house size) from outdoors to the return of the central air distribution fan (see diagram below). This outside air should be filtered before it enters the central return duct, and a balancing damper is advisable to give additional field control of the delivered outside air volume. The AirCycler control would be installed at the central fan cabinet, connecting to the thermostat wiring terminals. It functions to guarantee that fresh air will be periodically distributed throughout the house when there is no call for heating or cooling, but it is energy efficient since it only does this if the central fan has not operated for a preset time. A very important added benefit, is that builder call-backs due to thermal comfort or air quality problems may be greatly reduced because the AirCycler will even-out temperature, humidity and stuffiness conditions between rooms and the main body.

For single-point exhaust or single-point supply ventilation systems, the supply or exhaust point is usually located in the main body of the house. In this case, closed rooms, such as bedrooms, will not receive adequate ventilation air unless the central system fan operates to mix air between the main body and the closed rooms. Rather than operating the central system fan continuously, which can waste energy and can also lead to moisture related problems in humid climates, the AirCycler control can be set to periodically distribute ventilation air throughout the house during stagnant periods when there is no call to circulate air for purposes of heating or cooling.

Enhanced Temperature Control Systems

Thermostats are typically located in a central area and are expected to serve an entire zone that usually includes closed rooms, and often, more than one floor level. Temperature conditions can vary widely between the thermostat location and extremities of the space the thermostat serves. A practical solution to this problem could be to utilize the central system fan to average the overall space conditions by mixing. Rather than operating the central system fan continuously, which can waste energy and can also lead to moisture related problems in humid climates, the AirCycler control can be set to periodically mix house air during stagnant periods when there is no call by the centrally located thermostat to circulate air for purposes of heating or cooling.

Enhanced Humidity Control Systems

In humid climates, dehumidification, separate from the central cooling system, may be used to maintain comfort in seasons where there may be long periods of high humidity while indoor temperatures are within personal comfort ranges. In order to reduce system cost, it may be practical to locate a single dehumidifier in the main body of the house. In this case, closed rooms, such as bedrooms, will not receive the dehumidification benefit unless the central system fan operates to mix air between the main body and the closed rooms. Rather than operating the central system fan continuously, which can waste energy and can also lead to moisture related problems in humid climates, the AirCycler control can be set to periodically distribute dehumidified air throughout the house during stagnant periods when there is no call to circulate air for purposes of heating or cooling. For either dehumidifiers that are connected to the central air distribution system ducts, or for dehumidifiers that are stand-alone, humidistats are usually located in a central area and are expected to serve an entire zone that usually includes closed rooms, and often, more than one floor level. Humidity conditions can vary widely between the humidistat location and extremities of the space the humidistat serves. A practical solution to this problem could be to utilize the central system fan to average the overall space conditions by mixing. Rather than operating the central system fan continuously, which can waste energy and can also lead to moisture related problems in humid climates, the AirCycler control can be set to periodically mix house air during stagnant periods when there is no call to circulate air for purposes of heating or cooling.

Air Cleaning Systems

Air Cleaner or Special Filtration Equipment at the Central Air Handler Return

Air cleaning or special filtration systems that locate the cleaning or filtration media at the return side of the central system air handler will perform their intended function only when the central system fan is operating. Rather than operating the central system fan continuously, which can waste energy and can also lead to moisture related problems in humid climates, the AirCycler control can be set to periodically distribute cleaned or filtered air throughout the house during stagnant periods when there is no call to circulate air for purposes of heating or cooling.