Evaporative Pre-cooler Residential Air Conditioning Condenser Coil

Abstract

An evaporative pre-cooling system for increasing the efficiency of a residential air conditioner condensing unit utilizing a wet medium in contact with low velocity moving air allowing evaporation to occur across the wet medium thereby reducing the associated dry bulb air temperature of the air moving across the wet pad as the air absorbs moisture. In the present invention, the embodiment of the pre-cooling apparatus encapsulates the condensing unit with a wet cellulose media, water not absorbed during the evaporation cycle is recycled, and water generated by the evaporator coil is discharged into the sump to further reduce tap water consumption. In the embodiment of the present invention, the wet pre-cool mode is thermostatically in parallel with the electrical circuit energizing the pre-cooler system in tandem with the air conditioning compressor motor. The embodiment of the pre-cooling apparatus is constructed of cellulose evaporative pads, plastic top, plastic upper distribution channels, plastic lower water recovery channels, polyvinyl chloride (PVC) piping and fittings for water distribution, plastic frame, PVC for water drains, plastic sump reservoir, and plastic close-off panels providing total recyclability of the embodiment of the complete evaporative pre-cooler enclosure apparatus.

Description

STATEMENT

Specification in compliance with 37 CFR 1.125(b) includes no new matter

BACKGROUND

Prior Art

The following prior art presently appears relevant:

U.S. Patents
Patent Number	Kind Code	Issue Date	Patentee
4,212,172	B1	1980 Jul. 15	Manno
		reissued Aug. 30, 1983
4,028,906	B1	1977 Jun. 14	Ginegold et al.

Modern air conditioner systems are comprised of an evaporator coil, blower section, a compressor, a vertically positioned condenser coil, and a horizontally positioned fan. With respect to the refrigerant condensing component in a modern residential air conditioning system, in general ambient dry bulb air is pulled through a vertically positioned condensing coil and discharged out the top of the condensing unit. As the high pressure refrigerant gas passes through the condenser coil, heat is transferred from the refrigerant gas to the atmosphere by condensing the high pressure refrigerant gas discharged from the air conditioner system compressor into a liquid thereby completing the high side component of the refrigeration cycle.

It is universally accepted that lowering the saturated condensing temperature of an air conditioning condensing unit will increase the energy efficiency of that condensing unit. An application of the first law of thermodynamics to Carnot's theoretical performance of an ideal air conditioner immediately suggests the importance of reducing the high temperatures to which heat is rejected during the refrigeration process: COP=T₂/(T₁−T₂)

Where:

• • COP=Coefficient of performance
  • T₁=absolute temperature of the working fluid in the condenser at Which heat is rejected to the atmosphere (^Kelvin)
  • T₂=absolute temperature of the refrigerant at which heat is absorbed from the house interior (^Kelvin)

Based on Carnot's Law, a standard residential air conditioner evaporator with a refrigerant temperature equal to 280° K (45° F.) and a peak summer outdoor temperature of 308° K (95° F.) would yield a 14° K (25° F.) temperature difference between the condensing and heat sink temperatures providing a typical condensing temperature of 322° K (120° F.). Thus, the theoretical maximum coefficient of performance for such an air-cooled cycle would calculate out a coefficient of performance equal to 6.7.

Further manipulation of this equation shows that the air conditioner machine's coefficient of performance can be theoretically improved by about 1.4% for each degree Fahrenheit that the outdoor heat sink temperature is lowered. Taking into account compressor inefficiencies, refrigerant pressure drop, and friction losses, it is generally accepted that the energy efficiency rating of residential air conditioners is improved by approximately 1.2% per each degree as the outside ambient dry bulb air temperature is lowered over the range between 322° K and 301° K (120° F. and 82° F.).

Several types of ambient air pre-coolers have been proposed for example U.S. Pat. No. 4,212,172 Manno (1980 reissued 1983) utilized pressure, spray nozzles, water, a fiberglass incline, and turbulent air to pre-cool the air upstream of the condenser coil. In U.S. Pat. No. 4,028,906 Ginegold et al. (1977) utilized high pressure and nozzles to create a mist within the condensing unit to pre-cool the air upstream of the condenser coil. Both designs effectively lower the ambient air temperature through evaporation, however both systems expose the condensing unit to excessive amounts of moisture potentially accelerating corrosion shortening the useful life of the condensing unit and both systems require significant amounts of water during the pre-cooling process and neglect to capture and re-circulate the source water back through the system to minimize water consumption.

SUMMARY

The embodiment of my evaporative pre-cooler apparatus cools the ambient air entering the condenser coils of an air conditioning system using simple evaporation. The embodiment of my evaporative pre-cooler apparatus is comprised of evaporative cellulose pads positioned in front of the condensing coils providing moisture absorption with the associated psychometric ambient temperature drop as the low velocity air as is pulled through and across the evaporative cellulose pad by the air conditioning system condenser fan.

Advantages

Accordingly the advantages of the embodiment of my evaporative pre-cooler apparatus are as follows: the pre-cooler apparatus is a self-contained separate system easily installed to both existing and future residential air conditioning systems, utilizes low flow rate water delivery system with low velocity air movement to facilitate lowering air temperature without exposing the air conditioner condenser components to additional moisture, captures and recycles source tap water not evaporated from the cellulose pad during the evaporative cycle limiting the water consumption usage to the evaporation cycle only, captures and uses the air conditioner evaporator coil condensation further reducing the total source tap water consumed during pre-cooling, and the apparatus' enclosure consists of recyclable materials including cellulose, Polyvinyl chloride (PVC), and plastic materials.

Drawings

Figures

FIG. 1 is a three dimensional left side angle front view of apparatus illustrating, External components, connections, and overall housing design

FIG. 2 is a front cut-away view illustrating how apparatus encapsulates the air conditioning condensing unit, the water return channel, sump pump, and water distribution system

FIG. 3 is the rear view of apparatus illustrating the low voltage electrical switch connections from the air conditioning condensing units and plenum close-off panels of apparatus

10 Top Cover            12 Condensation Drain Pipe
14 Sump                 16 Sump Fill Solenoid
18 Sump Drain Solenoid  20 Lower Close-off
22 Water Discharge Pipe 24 Cellulose Wet Media
26 Ball Valve           28 Mechanical Float
30 Water Return Pipe    32 Water Recovery Drip Channel
34 Rear Close-off       36 Air Conditioner Thermostat
38 Sump Pump

DETAILED DESCRIPTION OF THE INVENTION

The present invention encapsulates the air conditioning condensing unit with evaporative cellulose pads, with said apparatus having a plastic top cover, lower close-offs on four sides, and vertical close-offs on rear of apparatus creating an enclosure that routes the ambient air across and through the evaporative cellulose pads prior to the ambient air moving across and through the air conditioning condenser coil.

On degree days, when the ambient temperature is equal to or greater than the temperature set point, the apparatus' thermostat (monitoring ambient dry bulb temperature) energizes the “normally open” drain line solenoid (closing the sump drain line), energizes the “normally closed” solenoid valve feeding water to the mechanical float (filling the sump reservoir with water), and energizes the sump pump on/off relay (ready pump for duty).

On degree days, when the apparatus' pre-cool sump pump relay is thermostatically energized in parallel with the air conditioning compressor unit via the air conditioning system thermostat inside the residence, the sump pump is energized pumping water from the sump reservoir to the PVC distribution pipe delivering a low velocity stream of water across the top of a cellulose pad encapsulating the air conditioning condensing unit. The cellulose evaporative pads absorb the water from the distribution pipe providing a wet medium for air to flow through and across. As the condensing unit fan pulls air through the 85% efficient cellulose wet pad, the air absorbs moisture and drops in temperature based on the formula t2=t1−((t1−t3)×0.85).

Where:

• • t2=air temp leaving evaporative pad (° F.)
  • t1=ambient dry bulb air temperature (° F.)
  • t3=ambient wet bulb air temperature (° F.)
  • 0.85=wet pad efficiency of evaporation

Water not absorbed by the cellulose evaporative pad or evaporated from the cellulose wet pad during the pre-cool cycle is captured via a channel underneath the cellulose evaporative pad and returned to the sump reservoir for recirculation through the water distribution system, and once the refrigeration cycle initiates condensation water generated by the air conditioning evaporator coil is drained into the apparatus sump reservoir for use in water distribution system.

When the present invention pre-cool circuit is thermostatically de-energized in parallel with the air conditioning compressor unit via the air conditioning system thermostat inside the residence, the sump pump relay is de-energized until air conditioning and pre-cooling is called for again by the air conditioning thermostat.

When ambient temperature falls below the degree day's ambient dry bulb set point temperature, the apparatus' thermostat de-energizes the “normally open” drain line solenoid” (draining water from the sump reservoir), de-energizes the “normally closed solenoid valve (shutting off feed water from source tap to the mechanical float), and de-energizes the sump pump on/off relay.

FIG. 1 referring to three dimensional view of apparatus where 10 is the plastic top with plastic channel cover section of unit housing the water distribution system made up of PVC pipe running the length of the evaporative cellulose pad medium. 12 is the PVC drain line from air-conditioning blower/evaporator pan capturing condensation water from the evaporator coil and delivering the water to the sump reservoir to be mixed with source water from tap. 14 is the plastic water sump reservoir. 16 is the “normally closed” water fill solenoid. 18 is the “normally open” sump drain solenoid. 20 is the lower close off. 22 is the water discharge line made up of PVC pipe delivering water to the top of the evaporative cellulose pad through the PVC water distribution pipe. 24 are the evaporative cellulose wet pads. 26 is the adjustable plastic hand valve for balancing the water flow rate to the left and right side water distribution pipes.

FIG. 2 is a front cut-away view of apparatus illustrating how the apparatus encapsulates the air conditioner condensing unit where 12 is drain line from PVC pipe from the air conditioner evaporator coil sump delivering condensation to apparatus sump reservoir. 22 is the PVC main discharge line delivering the mixture of condensation and source tap water to the water distribution pipe. 38 is the sump pump delivering the sump water to the top of the cellulose pad through the PVC water distribution pipe. 28 is the water inlet mechanical float maintaining the sump reservoir at a fixed water level. 30 is the PVC drain connection from plastic water recovery channel to sump reservoir. 32 is the recovery channel that captures water not evaporated across cellulose pad or absorbed by evaporative cellulose pad. 24 is the evaporative cellulose pad. 22 is the water PVC distribution pipe illustrating low velocity water flowing on to top of evaporative cellulose wet pad.

FIG. 3 is the rear view of apparatus where 26 is the plastic hand valve for balancing the water flow to the left and right side water distribution pipes. 34 is one of the plastic rear close-off panels from apparatus to air conditioning condensing unit. 36 is the low voltage electrical connection point from air conditioner thermostat to air conditioning condensing unit in parallel with apparatus. 22 is the main PVC discharge line delivering water to the water distribution pipe. 12 is PVC drain line from the a/c evaporator coil pan to apparatus sump reservoir

Pre-cool Mode Control logic: When the outside dry bulb temp is equal to or greater than degree day ambient temperature set point, the apparatus will prepare for pre-cool mode by energizing the fill solenoid valve (sump fills with h2o), energizing the dump solenoid valve (close sump drain), and energizing the sump pump circuit (sump pump ready for cycling). When the air conditioning system interior thermostat energizes the condensing unit low voltage control circuit, the pre-cool mode energizes the sump pump relay energizing the sump pump (water flows across evaporative cellulose pad). The evaporative pre-cool mode cycles on and off in parallel with air conditioning condensing unit

Claims

1. An apparatus for pre-cooling the ambient air entering the condenser coils of an air conditioning system comprised of an evaporator, blower, compressor, condenser, and fan, said apparatus having four sides of an evaporative cellulose pad media arranged as to provide moisture absorption by low volume air as it is pulled through and across the evaporative cellulose pad by the air conditioning system condenser fan, said apparatus having a top, interior frame, lower bottom and rear close-off panels, said apparatus having a sump pump pumping a mixture of tap water and condensation water from the air conditioner system evaporator coil up from a sump reservoir and through a Polyvinyl chloride (PVC) pipe directing a low velocity flow of water directly onto the top of the evaporative cellulose pad, with excess water not absorbed by the evaporative cellulose pad and water not evaporated across the evaporative cellulose pad collecting in the lower channel and draining back into the sump reservoir, said apparatus having a mechanical float level maintaining a fixed water level in the sump reservoir, said apparatus having the feed water from the tap water source, said apparatus having an electrical solenoid controlling the sump reservoir water dump, said apparatus 2. having a remote electrical control panel with a thermostat monitoring the ambient dry bulb air temperature, energizing and de-energizing the sump pump, electrical relays, and electrical solenoid valves, said apparatus increasing the energy efficiency of the air conditioning system by lowering the saturated condensing temperature of the air conditioning system by pre-cooling the ambient dry bulb air temp prior to the air flowing across and through the condensing unit condenser coil.

2. The apparatus as recited in claim 1 wherein is constructed of cellulose evaporative pads, plastic top, plastic upper distribution channels, plastic lower water recovery channels, PVC piping and fittings for water distribution, plastic frame, PVC for water drains, plastic sump reservoir, plastic lower front and rear side close off panels providing total recyclability of the complete evaporative pre-cooler enclosure apparatus.

3. The apparatus as recited in claim 1 wherein utilizes low velocity air flow and low velocity water distribution maximizing the moisture absorption across and through the evaporative cellulose pad without directly exposing the air conditioner condenser coil to excess water protecting the condenser coil from abnormal scaling and/or corrosion.