SFT (Smart Fan Technology) is an exclusively licensed, proprietary HVAC energy efficiency measure designed to automatically adjust the HVAC ventilation fan to stay on for an extended period of time after the cooling and heating unit cycles off. Most systems are designed for the fan to be set to run 0, 30, 60 or 90 seconds after cycling down automatically. SFT reads recent system activity and tells the fan to remain on for a precise amount of time, optimizing performance of each cycle. SFT tells the fan exactly how long to run, as long as five minutes twenty seconds, to most efficiently use the conditioning capacity of the elements of the HVAC system. SFT increases efficiency and reduces the number of times the HVAC system cycles on and off during a given time period. eco-T-0006 X with SFT is a smart chip designed specifically to reduce energy (kWh) consumption and utility costs. Independent studies show seasonal reduction of 12-15 % on HVAC energy expenses.
A typical HVAC consists of heating unit, air conditioning unit and the ventilation fan or blower at the air handler unit. A thermostat is used to control the conditions of the air in a conditioned space by sending control signals to the HVAC furnace or heater, air conditioning and blower fan controller housed in a PCB located at the air handler unit. HVAC fan controller typically operates the ventilation fan for 0 second to 90 seconds after the furnace or air conditioner compressor has been turned off.
Studies have shown that even after this 90 second duration, the furnace surface and the air conditioner cooling coil still has some energy left. This wasted energy is not delivered to the conditioned space when the ventilation fan stops blowing.
There is a need in a HVAC system with a secondary fan controller device (the patent pending eco-T-0006 X) that can be used to recover additional heating and cooling capacity and operate HVAC equipment at a higher efficiency. In cases where the compressor never shuts down due to very hot outside temperature, water still condenses onto the cooling coils after the compressor has been running for more than 30 minutes continuously, it makes sense to shut the compressor down for a few minutes to let the water evaporates away while keeping the fan running.
The eco-T-0006 X adjusts the ventilation fan run time automatically for heating based on gas valve activation time or furnace operating time or heat pump activation time. For air conditioning, the same eco-T-0006 X will adjust fan run time automatically for cooling based on air-conditioning compressor run time. The amount of time the ventilation fan continues to operate after the furnace is turned off or after the air conditional compressor is turned off, varies with the amount of time the furnace or compressor has been running.
The eco-T-0006 X uses microprocessor and firmware and unique circuitry to achieve this. The furnace’s additional fan run time indicates how much left over heat is stored in the heat exchanger. The air conditioner compressor’s additional run time indicates how much cold water is condensed on the evaporator coil.
The eco-T-0006 X recovers and delivers more heating and cooling energy to the conditioned space than is possible with original HVAC fan controllers based on thermostat signals.
The eco-T-0006 X improves the efficiency of HVAC equipment by delivering additional heating or cooling capacity for a small amount of additional electric energy (kWh).
Air conditioners cool conditioned spaces by removing sensible and latent heat from the return air which reduces the supply air temperature and humidity.
Latent heat is removed as water vapor is condensed out of the air due to the temperature of the evaporator coil being less than the return air dew point temperature.
Latent heat is the quantity of heat absorbed or released by air undergoing a change of state, such as water vapor condensing out of the air as water onto a cold evaporator coil or cold water evaporating to water vapor which will cool the air.
Most evaporators are cold and wet (below 40 to 50°F) after the compressor turns off. Cooling energy left on the evaporator coil after the compressor turns off is generally wasted. The evaporator absorbs heat from the attic and cold water on the coil flows down the condensate drain. The eco-T-0006 X recovers the remaining cooling energy from evaporator coil by operating the fan after the compressor turns off to cool the conditioned space.
Most furnace heat exchangers are still hot (above 135 to 210°F) after the furnace fan turns off. The r eco-T-0006 X recovers the remaining heat energy from the hot furnace heat exchanger after the furnace turns off and delivers this heat to the conditioned space.
The eco-T-0006 X works by hijacking the fan control signals emitted by the thermostat and replaces it with the new fan control signal emitted by the eco-T-0006 X itself. In this way, the HVAC fan controller only receives the fan control signals from the eco-T-0006-X itself and not from the thermostat directly.
eco-T-0006 X reads the commands from the thermostat and computes the additional ventilation fan run time. The eco-T-0006 X then sends the adjusted command signal to the HVAC fan controller at the air handler unit requesting it to run for a programmed additional extended time. For the eco-T-0006 X to work universally, it has to interface with every type of thermostats used in HVAC system. There are many thermostats where the fan output command signal goes into a floating or unknown state when the thermostat is shut off by putting the thermostat switch to system off.
In such a case, if a fan extender device is connected to the thermostat, the fan command signal being in unknown state, could be read in as ON state, and the fan extender device may turn the fan on and run continuously.
However, the eco-T-0006 X is the only device in the market that is able to read any unknown or floating signals from the thermostat fan command signal and make it as a 24vac or 0vac state. By using the eco-T-0006 X, the fan will always be turned off even when the green fan line is in float state.