Many residential and commercial air conditioning systems achieve a cooling effect by alternatively expanding and compressing a heat exchange fluid and causing heat exchange between the heat exchange fluid and the inside air and ambient outside air, sequentially.
At the step of cooling the inside air, a heat exchange fluid first goes through a sudden expansion, changing phase from liquid to gas, causing the heat exchange fluid to suddenly experience a significant temperature drop. The cool gas is then typically passed through heat exchange coils. Inside air is then passed over the cool coils, thus resulting in cooled inside air. As a consequence, the heat exchange fluid is warmed and begins a recycling step.
At the step of recycling the heat exchange fluid, the newly warmed heat exchange fluid is condensed into the liquid phase by a condenser, which causes the heat exchange fluid to experience a further temperature increase. The hot heat exchange fluid, now in the liquid phase, is then typically passed through another set of coils. Ambient outside air is then passed over the hot coils, thus cooling the hot coils. As a consequence, the ambient outside air is warmed and expelled from the system.
The step of recycling the heat exchange fluid typically occurs in an air conditioning condenser unit, situated outside a residence or commercial building. Typical air conditioning condenser units comprise an air inlet for ambient air, coils for allowing heat exchange between the hot heat exchange fluid and the ambient air, and a fan for blowing the ambient inlet air through the coils and out from another end of the air conditioning condenser unit. Variations of air conditioning condensing unit designs may exist, but a main feature is that each acts as a heat exchanger, facilitating heat exchange between a hot heat exchange fluid and the cooler outside air.
A limitation of a typical air conditioning condenser unit is that it can only cool the heat exchange fluid down to the temperature of the outside air, at best. As a result, the warmer the outside air is, the less efficient and more power-intensive the overall cooling process becomes, and the longer the condenser unit needs to operate in order to reach a desired level of cooling.
Proposals have been made to improve the efficiency of air conditioning condenser units by pre-cooling the inlet air before it is used for heat exchange with the hot coils containing the heat exchange fluid. Such solutions may improve power consumption or run-time of air conditioning condenser units by allowing the air conditioning condenser unit to run for less time to achieve a desired level of cooling of inlet air. Such solutions are described in U.S. patent application Ser. No. 13/751,579 (the '579 application) and U.S. patent application Ser. No. 12/255,834 (the '834 application), but such solutions suffer from a number of drawbacks.
The solution disclosed in the '579 application, for example, involves the delivery of water onto a screen mesh to cool the inlet airstream. This proposed solution however, does not account for the resulting water corrosion that may occur to the air conditioning condenser unit during operation. The solution disclosed in the '579 application also involves a complicated water flow rate management system requiring a microcontroller, sensors, and other parts, which is not conducive to simple installation and reliable performance.
The solution disclosed in the '834 application, on the other hand, addresses the water corrosion problem by employing hexametaphosphate, but still suffers from the drawbacks of complicated installation and questionable reliability of complicated systems, and suffers from the additional drawback of managing hexametaphosphate.
Therefore, there is a need to provide a pre-cooling system that improves air conditioning condenser unit power consumption or run-time, is reliable and easy to install and that addresses the problem of water corrosion.
USPTO Backgrounds
USPTO Backgrounds