TECHNICAL FIELD

The present disclosure relates generally to a heating and air conditioning system, and more specifically to a multi-zone forced air heating and air conditioning system.

BACKGROUND

Controlling the volume of heated or cooled air distributed to different areas of a multiple zone system has been primarily accomplished with a VAV (variable air volume) damper system. VAV systems include a thermostat which is typically located in an occupied space and controls a damper, which limits the primary air flow from a central air handler. VAV systems are often deficient in that control of the air volume is managed by the damper, which creates a high pressure upstream of the damper and a lower pressure downstream of the damper. This lower downstream pressure is negatively affected by friction losses in ductwork, grills and diffusers which limit the VAV system's ability to efficiently distribute air to remote areas of the multiple zone system. Some systems seek to eliminate the duct losses downstream of the damper by locating the damper in the air outlet grille, but this complicates the control of the system and also creates the potential for increased noise as the velocity of the air increases locally as the damper closes.

Another deficient aspect of the VAV system is that the higher pressure on the upstream side can be considerable for the system to perform as designed, and thus creates energy loss. Due to the need for larger fan motor(s) in the central air handler, the VAV damper creates a restriction and the duct energy losses are increased with higher pressures and air velocities. Another disadvantage is the additional integrity provision needed on the high-pressure ductwork to reduce leaks. Modern VAV systems reduce these energy losses for part-load operation with variable speed operation of the central fan motor, but this further reduces the effectiveness of the downstream air distribution system. This strategy is further limited by the range of air flow required by conditioning system.

And as anyone trained and versed in the art of air conditioning is aware, the evaporator portion of a conventional AC system must operate within a limited range of air flows for the for the basic operation of the refrigeration cycle of the working fluid (Freon, ammonia, etc.) through the heat transfer element (coil) conditioning the air stream delivered to the occupied space being served by that system. If the air flow rate through the coil is too little, the coil will get too cold and freeze the condensate and plug the coil resulting in system shutdown and failure. If the air flow rate is too high, the temperature of the air leaving the coil will rise above saturated conditions and moisture will remain in the air stream increasing humidity in the space.

In fact, some have attempted fan powered multi zone systems, however, they all have a deficiency in that they can they do not have a means of controlling air flow across the heat transfer coil within acceptable ranges required for commercially available HVAC equipment. The volume of air moving over the heat transfer coil in the indoor heat transfer unit (ITHU) is critical to the operation and effectiveness of conventional Direct Expansion (DX) air conditioning systems. Too small of a flow volume and the coil will freeze and the system will cease to function. Conversely, with too high of an air flow volume (for any type of AC system) through the heat transfer coil, the air temperature will not be reduced below the saturation temperature and the system will fail to remove humidity from the supply air stream. Multi-zone fan powered systems (Cohen: PCT/IL2007/000833) do not address the issue of combined air flow through the IHTU. In one instance (Jacob: PCT/AU90/00068) this issue was addressed by modulating the capacity of the compressor (or the outdoor component of the IHTU), both of which are either inoperable or not commonly available and require extensive controls which are not commonly understood and implemented. Further, the controls and equipment thereof to allow for modulating the capacity of the compressor are not economically viable for most common installations.

Accordingly, it can be seen that needs exist to improve HVAC control systems to improve efficiency and effectiveness for multi-zone systems. It is to the provision of a zoning system for air conditioning (HVAC) equipment (and systems and methods thereof) meeting these and other needs that the present invention is primarily directed.

SUMMARY

In example embodiments, the present disclosure solves the problem of simultaneously optimizing a unitary Air Conditioning (AC) system while also satisfying the requirements of individual zones. Individual zones systems do not have the means for reconciling their demands with the net conditions needed to optimize the heat transfer system. The systems and methods as described herein are intended to monitor and operate the air moving portion of a conventional AC system, but could be applied to any combination of cooling and/or heating systems such as refrigeration (including variable compressor systems), hydronic, resistance heat, vapor compression, gas furnace, thermoelectric/peltier, etc.

In one aspect, the present disclosure describes a method for achieving air conditioning zones without restrictive dampers. The method dynamically adjusts the air balance of an air conditioning system to match the supply of conditioned air (i.e., air that has been conditioned to be hot or cold) to the thermal demands of the zones it serves. The method optimizes the effectiveness of an air conditioning system by directing the thermal capacity of the system to the zones requiring service without overcompensating in non-demanding zones.

In another aspect, the present disclosure relates to a system for distributing conditioned air to a plurality of zones. The system includes an indoor heat transfer unit for thermally conditioning air and a plurality of fans which are operably connected to the indoor heat transfer unit to draw a volume of thermally conditioned air from the indoor heat transfer unit and direct the volume of the thermally conditioned air to a plurality of zones. The plurality of fans continuously monitor and control the volume of thermally conditioned air directed to each of the plurality of zones. Each of the plurality of fans are independently operable.

In still another aspect, the present disclosure relates to a method to automatically adjust the air balance of a heating ventilation and air conditioning system (HVAC). The method includes directing a measured volumetric rate of air through at least two adaptive distribution and control elements positioned remotely in at least two respective air circuit paths.

In yet another aspect, the present disclosure relates to a system for distributing conditioned air to at least one remote zone. The system includes an indoor heat transfer unit for thermally conditioning air and at least one fan that is operably connected to the indoor heat transfer unit to draw a volume of thermally conditioned air from the indoor heat transfer unit and direct the volume of the thermally conditioned air to at least one remote zone. The at least one fan continuously monitors and controls the volume of thermally conditioned air directed to the at least one remote zone. The at least one fan is positioned remotely from the indoor heat transfer unit. The operable connection between the indoor heat transfer unit and at least one of the plurality of fans is damperless.

In still another aspect, the present disclosure relates to a method for distributing conditioned air to a plurality of zones. The method includes thermally conditioning a volume of air with indoor heat transfer unit. The method also includes drawing the volume of thermally conditioned air from the indoor heat transfer unit with a plurality of fans operably connected to the indoor heat transfer unit. The method also includes directing the volume of the thermally conditioned air to a plurality of zones with the plurality of fans. The plurality of fans continuously monitors and controls the volume of thermally conditioned air directed to each of the plurality of zones. Each of the plurality of fans is independently operable.

According to example embodiments, a central controller activates or deactivates, dynamically increasing or decreasing the volumetric flow rate of the plurality of fans so as to optimize the degree of control to each of the plurality of zones as demanded by thermal loads of the plurality of zones to better decouple the thermal loads from a supply capacity of conditioned air provided by the indoor heat transfer unit. In example embodiments, the central controller adjusts the speed of each individual fan of the plurality of fans to provide a volume of air flow to match the thermal load of the zone it serves while maintaining the net air flow through the heat transfer element of the air conditioning system at a fixed volumetric rate predetermined by the system's thermal capacity and user performance goals.

In example embodiments, the central controller includes a PID controller, and wherein the PID controller is configured to account for and perform one or more calculations relating to a temperature difference for each of the plurality of zones between each respective set-point temperature and measured temperature, individual measured air flow rates within each duct, and the preset air flow rate, the PID controller summing the measured air flow rates and comparing it to the preset air flow rate to calculate a proportional multiplier, the proportional multiplier being multiplied by the prior-measured air flow rates to determine values for adding to the prior-measured air flow rates to obtain a set of first adjustment values. In example embodiments, the PID controller is configured to again measure the individual air flow rates passing through each duct such that the sum thereof is compared to the preset air flow rate to obtain a multiplier for proportionally adjusting the individual air flow rates to obtain a set of second adjustment values. In example embodiments, the central controller is configured to conduct a substitution process of the set of second adjustment values, wherein the values remain the same if they fall within a preset air flow range and wherein the values are substituted with a maximum or minimum preset air flow rate if the value thereof exceeds the maximum or minimum preset air flow rate.

In yet another aspect, the present invention relates to a method of cooling or heating a structure having at least two zones, the structure including an outdoor compressor, an indoor heat transfer unit and heat pump, the structure having ducts connected between the indoor heat transfer unit and the zones, each of the ducts having an individual fan in communication therewith to draw air from the indoor heat transfer unit and across a coil to the desired zone at the desired rate, so long as the sum of the volumetric air flows through the ducts remains at a preset volumetric air flow rate. The method includes drawing air across the heat transfer coil of the indoor heat transfer unit at the preset volumetric air flow rate; measuring individual air flows rates of the at least two zones within at least a portion of the ducts such that air flow signals generated by the measuring thereof are sent to a control system for processing; summing the individual zone air flow signals in the control system to generate an instantaneous measured net volumetric air flow rate for the entire air volume moving across the coil of the indoor heat transfer unit; comparing the measured net volumetric air flow rate to the preset volumetric air flow rate; and proportionally adjusting the individual air flow rates to maintain the instantaneous measured net volumetric air flow rate at the preset volumetric air flow rate as if there was a single fan operating the system.

In yet another aspect, the present invention relates to a variable air flow air conditioning system for conditioning the air of multiple zones of a structure including an air conditioning unit having a heat transfer element; a plurality of ducts extending from the air conditioning unit to each of the multiple zones; a plurality of variable speed fans, wherein at least one fan is positioned to communicate within its respective duct between the air conditioning unit and the multiple zones; a plurality of zone sensors, wherein at least one zone sensor is positioned within each respective zone of the multiple zones so as to provide temperature measurements of the zones thereof; a plurality of air flow sensors, wherein at least one air flow sensor is positioned within each respective duct so as to obtain the volumetric flow rate of the conditioned air flowing from the air conditioning unit; and a controller configured to communicate with the air conditioning unit, the variable speed fans and the air flow sensors, wherein the central controller activates or deactivates so as to dynamically increase or decrease the volumetric flow rate of the plurality of fans so as to optimize the degree of control to each of the multiple zones as demanded by thermal loads of the plurality of zones, and wherein the central controller adjusts the speed of each individual fan of the plurality of fans to provide a volume of air flow to match the thermal load of the zone it serves while maintaining a net volumetric air flow rate through the heat transfer element of the air conditioning unit at a preset volumetric air flow rate predetermined by the system's thermal capacity and user performance goals.

In example embodiments, the air conditioning unit is a split system including outdoor compressor, an indoor heat transfer unit, and a heat pump. In other example embodiments, the air conditioning unit is a packaged system including a compressor, a heat transfer unit and a heat pump.

These and other aspects, features and advantages of the invention will be understood with reference to the drawing figures and detailed description herein, and will be realized by means of the various elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following brief description of the drawings and detailed description of example embodiments are explanatory of example embodiments of the invention, and are not restrictive of the invention, as claimed.

