US20140231042A1 - System for Reducing the Condensing Temperature of a Refrigeration or Air Conditioning System by Utilizing Harvested Rainwater - Google Patents

Abstract

An evaporative air conditioning heat transfer apparatus comprising a collection surface for diverting liquid into a channel, a reservoir capable of receiving and storing the diverted liquid, at least one conduit for transferring liquid from the reservoir to a liquid dispersion point, and a regulator positioned between the reservoir and the liquid dispersion point and configured to control the amount of liquid released at the liquid dispersion point, wherein the liquid dispersion point is configured to distribute the liquid over a condensing coil.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is related and claims priority to U.S. Provisional Patent Application Ser. No. 61,766,242 filed on Feb. 19, 2013, the complete and entire disclosure of which is hereby expressly incorporated by reference herein.
TECHNICAL FIELD
• The present disclosure relates to refrigeration and air conditioning systems and specifically to processes and methods for reducing the condensing temperatures of such systems by sprinkling harvested rainwater over standard (or manufacturer's modified) condensing coils to thereby allow evaporative condensing to take place.
BACKGROUND OF THE INVENTION
• Most air conditioning and refrigeration systems utilize the Carnot Cycle, which is a vapor-compression refrigeration type of system. The basic components of this Carnot Cycle system consist of a compressor, a condenser, an expansion valve, and an evaporator. The majority of the energy input (typically electricity) is supplied to the compressor. The energy required to operate the compressor is largely a function of the “lift” or the compression ratio against which the compressor has to operate. The type of refrigerant also has some effect upon the amount of energy that is required to produce one ton of refrigeration (air conditioning), but the selection of refrigerant is typically based upon the environmental suitability of the specific refrigerant, as well as the cost of the refrigerant.
• The compressor “lift” can be best described as the pressure (condensing pressure) to which a compressor must elevate the incoming pressure (suction pressure). A Mollier Diagram for the specific refrigerant can precisely illustrate the thermodynamics of the compression portion of the Carnot Cycle.
• The compression ratio is often used by the compressor designer to describe the capability of a compressor geared towards a specific application—i.e., the compression ratio is the ratio of the absolute pressure at the condensing temperature (pressure) to the absolute pressure at the saturated suction temperature (pressure). The greater the compression ratio, the more energy that is required to raise the refrigerant gas from the suction pressure to the condensing pressure (i.e., the compression cycle).
• Typically, a standard air conditioning system operates at an evaporator temperature (saturated suction temperature and pressure) of +40° F. or +50° F. In the industry, it is commonly denoted as 40 F or 50 F. The corresponding saturated pressure varies according to the particular refrigerant being used. On the other hand, the compressor discharge pressure (condensing pressure less line losses) is a function of the method of condensing that is used.
• Residential and small commercial air conditioning and refrigeration systems utilize “air-cooled” condensing. This means that ambient air must be sufficiently lower in temperature than the refrigerant condensing temperature so that the refrigerant gas will “give up” its latent heat to be condensed from a gas (at condenser pressure) to a liquid (at condenser pressure). The driving force for condenser heat transfer is 95° F. air (a typical design summer day in many parts of the United States) being drawn across a condenser coil with a refrigerant temperature at 115° F. to 130° F. This driving force or temperature differential is 20 or 35 Fahrenheit degrees.
• An air conditioning unit with an air-cooled condenser can have a typical energy input of 1.3 KW per ton at peak load on a design summer day. Large commercial and industrial air conditioning and refrigeration systems typically utilize water-cooled or evaporatively cooled equipment which have cooling towers or evaporative condensers for achieving low condensing temperatures, particularly since cooling towers and evaporative condensers reject their heat based on ambient wet bulb temperatures (78° F. is a typical design wet bulb temperature for many places in the United States), as opposed to air-cooled equipment that reject heat against 95° F. typical summer dry bulb temperatures. Since cooling tower and evaporative condenser systems can get condensing temperatures to “approach” wet bulb temperature by 15 to 20 Fahrenheit degrees, a KW per ton energy usage of 0.6 to 0.9 KW per ton can be realized. Water cooled and evaporative cooled equipment can consume nearly half of the energy per ton as air cooled equipment. Although larger systems utilize water cooled and evaporative cooled equipment for the sake of energy savings, these types of systems have a higher first cost, a higher maintenance cost, and usually require more maintenance time due to water treatment concerns, etc. If properly maintained, water cooled and evaporatively cooled equipment and systems will have a longer operating life.
• To achieve a maximum efficiency in air conditioning and refrigeration systems, various means of lowering condensing pressures and corresponding saturated temperatures have been employed to achieve a low kilowatt input per ton of refrigerating effect. These methods vary according to ambient temperatures (both wet bulb and dry bulb), first cost considerations, simplicity and ease of operation and maintenance.
• Virtually all residential and small commercial air conditioning and refrigeration systems use air as a medium to remove heat from the condensing side of the refrigeration cycle. These systems are normally rated with 95° F. ambient air on the condenser. Most air conditioning and refrigeration systems will condense the standard refrigerants from a high pressure gas to a liquid at 115° F. to 130° F. depending upon the efficiency of the system and specifically, the thermal heat rejection size of the condenser. These air cooled condensers primarily are constructed of copper tubes and aluminum fins (spaced at 12 to 16 fins per inch) or a “spiny” type of extended surface. The copper tubes, through which the refrigerant flows, are typically one to four rows that are in a staggered configuration. The finned tubes make this an extended surface heat exchanger with the refrigerant gas being condensed within the tubes at 115° F. to 130° F. with cool air at 95° F. being drawn across the finned condenser coil by means of a fan.
• The refrigerant gas in the condenser is condensed from a high pressure gas at the condensing temperature to a high pressure liquid at the same temperature—merely a phase change. This high pressure liquid then flows to an expansion device (capillary tube, expansion valve, etc.) that expands the refrigerant from a high pressure liquid to a gas. This expansion of the refrigerant from a high pressure liquid to a low pressure gas occurs in the evaporator coil in the refrigeration system which results in the “cooling effect” or the “refrigerating effect.” The typical evaporator coil temperature in a residential air conditioning system may be 40° F. to 50° F., with the lower coil temperature providing for dehumidification by condensing moisture out of the air. This evaporator coil provides both sensible and latent heat transfer.
• The expansion device tries to regulate the coil temperature so as to maintain at least 10 Fahrenheit degrees of “super heat” which insures that all refrigerant that exits the evaporator coil is a gas. Refrigeration compressors only want to see gas—no liquids. The gas leaving the evaporator coil is saturated with some amount of “super heat.” This suction gas is then drawn into the compressor which then raises this 40° F. to 50° F. refrigerant gas at its saturated pressure to the condensing pressure at the corresponding 115° F. to 130° F. pressure. A halocarbon refrigerant that has been commonly used in air conditioning and refrigeration systems is R-22, chlorodifluoromethane. As an example, the corresponding saturation pressure at 40° F. evaporator temperature is 83 PSIA. The corresponding pressure at 115° F. condensing temperature is 257 PSIA. The compressor work (energy) required to raise a refrigerant gas from 83 PSIA to 257 PSIA requires typically 1.2 to 1.4 kilowatts per ton of refrigerating effect.
• Many larger air conditioning and refrigeration systems are known as “water-cooled” systems. Many of these systems will condense refrigerant in the condenser at 95° F. to 105° F. The corresponding R-22 pressures are 196 and 225 PSIA, respectively. Since the compressor does not have to raise the refrigerant from the evaporator pressure to as high of condensing pressure in a water cooled system, the compressor energy requirement is much less. Many “water-cooled” systems can operate at 0.60 to 0.90 KW/ton, or lower. Although the energy usage per ton on a water-cooled system is significantly less than an air-cooled system, the first cost of water-cooled systems is significantly more thus relegating water-cooled systems to large commercial and industrial applications.
• Water-cooled systems typically fall into three general categories of heat rejection apparatus and system configuration. They are: a) once-through water systems; b) cooling tower water systems; and c) evaporative condenser systems. To understand water-cooled systems, an understanding of the thermodynamics of air is necessary.
• A once-through water-cooled system removes heat in the condenser by sensible heat transfer, taking advantage of the cool well water or city water to achieve the low condensing temperature. Generally speaking, the water temperatures of once-through cooling water are not affected by ambient air temperatures or the thermodynamics of air. Once-through systems consist of water-cooled shell and tube or plate condensers that have refrigerant gas on one side of the heat exchanger and city or well water on the other side. This water source (city or well) can typically be 60° F. which easily permits refrigerant condensing to occur at 80° F. or 90° F. The water enters the condenser at, say, 60° F. and is discharged to the sewer at 80° F. to 90° F. The water usage could amount to 1 to 2 gallons per minute of water per ton of refrigerating effect.
• Once-through water systems have not been popular for many years although are still used on many older-designed and installed systems. There are many reasons why once-through water systems have fallen out of favor. The main reason stems from the formation of the Environmental Protection Agency (EPA) and the many and varied aspects of the Clean Water Rules and Regulations that have been enacted since the 1970's. These regulations regarding the water quality mandates for city and municipal water systems have raised the cost of water to be $1.00 to $4.00 per 1,000 gallons of water usage. More importantly, the cost of disposal of this once-through water can be two or three or four times the cost of purchasing the water. The cost of the various types and effectiveness of municipal sewage treatment plants has driven sewage disposal costs up. In short, today, in the United States, merely discharging water into ditches, streams, etc. is not permitted by the EPA. Essentially, the only legal way of discharging once-through water is through the municipal sewage treatment plants. The cost of purchasing once-though water and disposing it through the municipal sewage treatment plant can be cost prohibitive.
• The other often over-looked but major detriment to once-through water systems relates to the water quality itself Well water contains many dissolved minerals such as iron and calcium carbonate. These dissolved minerals will foul condensers causing the condensers to gradually lose their heat transfer effectiveness resulting in a major loss of system efficiency and ultimately leading to condenser failure.
• The most common means of condensing refrigerant gas from a high pressure gas to a high pressure liquid include the following: Water-Cooled Condensers; Air-Cooled Condensers; Evaporative Cooled Condensers; Adiabatic Air-Cooled Condensers.
• Water-cooled condensers are most commonly used on large commercial and industrial air conditioning systems that demand an optimum of energy efficiency. Most water-cooled systems utilize an evaporative cooling tower where some water is evaporated to cool the balance of the water. Since heat is rejected by evaporation, the water can be cooled to a temperature that “approaches” the wet bulb temperature. The wet bulb temperature is always equal to or lower than the dry bulb temperature. Hence, the lower wet bulb temperature can directly relate to a lower condensing temperature in the water-cooled air conditioning apparatus resulting in a lower energy input requirement for a ton of refrigerating effect.
• The three most commonly thought of thermodynamic properties of air are dry bulb temperature, wet bulb temperature, and relative humidity which are all interrelated. Cooling towers are rated only on wet bulb temperature. Of these three, the wet bulb temperature is the least understood. The psychrometrics of air define wet bulb as the temperature at which water evaporates. Although the dry bulb temperature can rise to over 120° F. at places on earth, the highest ambient wet bulb temperatures do not exceed 86° F. The normal peak design ambient temperature in many parts of the United States is 95° F. dry bulb temperature and 78° F. wet bulb temperature.
• Most cooling towers have a standard rating of producing 85° F. cold water when the ambient wet bulb is 78° F. This differential of 7 Fahrenheit degrees (85° F.-78° F.) is known as the “approach temperature.” This differential is the “driving force” that allows for evaporation to take place—the key method of heat transfer in evaporative cooled systems. This latent heat transfer takes advantage of the fact that every pound of water that evaporates, releases 1,000 BTU's of heat into the atmosphere (a reasonably close approximation of the latent heat of vaporization of water).
• A cooling tower is an evaporative heat exchanger where water to be cooled is distributed over an evaporating surface while air is forced through or drawn over this surface to enhance evaporation.
• On the typical hottest day of the summer (95° F. dry bulb temperature and 78° F. wet bulb temperature) a cooling tower can produce 85° F. cold water evaporatively. This 85° F. water is pumped into the condenser of a water-cooled air conditioning or refrigeration unit. This cold water (that enters the condenser at 85° F. and would typically leave at 95° F.) extracts heat in this water-cooled condenser by sensible heat transfer.
• Again, by taking advantage of evaporative heat transfer, water-cooled systems allow the condensing temperature of the refrigeration cycle to be 95° F. to 105° F. versus the higher condensing temperatures of 115° F. to 130° F. in air-cooled condensers.
• There are advantages and disadvantages to water-cooled systems utilizing cooling towers. The fundamental reason that a cooling tower is used is that it saves the user nearly 95% of the water that might be used in a once-through system. However, many owners and users don't want to have to address the water treatment systems and chemicals that are inherently a part of a cooling tower system. Aside from scale and corrosion control that can be accomplished by chemicals and chemical treatment or electronically/magnetically in non-chemical treatment systems, biological control is also required.
• It must be recognized that a recirculating type of cooling water system of which a cooling tower is an integral part tends to concentrate the dissolved minerals that are in the water. These dissolved minerals can scale or foul the heat transfer surfaces. This is why water treatment is required.
• Air-cooled condensers are most commonly used on residential and small commercial air conditioning and refrigerating systems due to simplicity of operation and low first cost. Since heat is transferred from the refrigerant gas at the refrigerant's condensing temperature (and corresponding pressure), the system's condensing temperature can only practically “approach” the ambient air dry bulb temperature by 20 to 35 Fahrenheit degrees. This high condensing temperature and resultant higher energy input per ton of refrigerating effect is the penalty that owners and users pay to achieve simplicity and a low first cost.
• Evaporative condensers are most commonly used on large air conditioning and refrigeration systems due to the requirement of optimal energy input per ton of refrigerating effect. Here the refrigerant gas transfers its heat at the system's condensing temperature which approaches the ambient wet bulb temperature. Practically, most evaporative condensers generate a condensing temperature that approaches the ambient wet bulb temperature by 12 to 17 Fahrenheit degrees. Although evaporative condensers can generate condensing temperatures that approach wet bulb temperatures by 5 to 10 Fahrenheit degrees, the first cost of the evaporative condensers and the physical space required by these over-sized units are detriments.
• Adiabatic air-cooled condensers are seldom used due to the complexity of the apparatus and system (installation, operation, maintenance, and higher first cost) as compared with air-cooled condensing systems. Adiabatic systems are characterized by adiabatically saturating the air to a temperature that very closely approaches the ambient wet bulb temperature. This saturated air temperature entering an air-cooled condenser is 10 to 15 Fahrenheit degrees lower than typical dry bulb temperature that a standard air-cooled condenser would see.
• Most attempts to increase air conditioning and refrigeration system efficiency have been devoted to larger systems which typically have operating staffs and budgets that permit the use of water-cooled systems with cooling towers or evaporative condensers. These larger systems also have the ability and infrastructure to accommodate the use of water for evaporation, the water treatment hardware and chemicals required to treat the water to minimize scaling and biological activity, and the disposal of bleed-off water that is a necessary part of any water treatment system.
• Some isolated cases include the spraying of city water or well water directly on an air conditioning finned condenser coil to reduce the condensing temperature. The mineral build-up on the finned condenser from the spraying of city or well water very quickly renders the condenser unserviceable. This coil spraying most closely approximates an evaporative condenser although evaporative condensers do not have finned coils and normally do have a good water treatment system and program.
• Since directly spraying a finned air cooled condenser coil creates problems with coil scaling, etc. due to the dissolved minerals normally found in all water sources, various attempts have been made to saturate air adiabatically via pads or some other method. These adiabatic units are found in small commercial units (approximately 50 to 100 tons) and have been discussed in U.S. Patent Publication No. US2010/0242534 A1 and U.S. Pat. No. 5,701,748. At this point, for a variety of reasons, these adiabatic systems have not proven to be viable options for lowering the condensing temperature on residential and small commercial air conditioning and refrigeration systems.
• The present invention is intended to improve upon and resolve some of these known deficiencies of the art.
SUMMARY OF THE INVENTION
• In accordance with one aspect of the present disclosure, an evaporative air conditioning heat transfer apparatus is provided and comprises a collection surface for diverting liquid into a channel, a reservoir capable of receiving and storing the diverted liquid, at least one conduit for transferring liquid from the reservoir to a liquid dispersion point, and a regulator positioned between or inside of the reservoir and the liquid dispersion point, the regulator being configured to control the amount of liquid released at the liquid dispersion point. In accordance with this aspect of the present disclosure, the liquid dispersion point is configured to distribute the liquid over a condensing coil.
• In accordance with certain embodiments, the regulator can be a valve or a pump, while the collection surface can be a roof of a house, building, or some other structure, (having a series of channels or gutters for diverting the liquid to the reservoir) or trench or some other means of capturing and conveying water to the reservoir from ground gutters, ground pipes, or other property rainwater drainage systems as may be present.
• To transfer the liquid from the reservoir to the liquid dispersion point, any series of conduits or pipes can be utilized in accordance with certain embodiments. Moreover, in accordance with certain aspects herein, the liquid dispersion points that are configured to release the liquid transferred from the reservoir can be one or more sprinkler heads or gravity distribution pipes or troughs that are positioned proximate the condensing coil (or coils) of an air conditioning system.
• To release the liquid from the liquid dispersion points, in accordance with certain aspects of the present disclosure, a regulator, such as a valve or pump, can be used to control the amount of liquid released over the condensing coils. Further, a controller can be incorporated into the system to mechanically or electronically drive the regulator if desired.
• In accordance with still another aspect of the present disclosure, a method for cooling refrigeration condensing coils is provided. According to this embodiment, rainwater is collected in a reservoir that is fluidly coupled to one or more dispersion units, such as sprinkler heads or gravity distribution pipes or troughs. The rainwater is capable of being distributed from the one or more dispersion units onto a condensing coil of an air conditioning unit, while the amount of rainwater distributed onto the coil can be regulated by a valve or pump that is located between the reservoir and the liquid dispersion points.
• In accordance with certain aspects of the present disclosure, the reservoir can be positioned above the one or more dispersion units to permit gravity to provide sufficient water pressure for distributing the rainwater onto the condensing coil from the one or more dispersion units. Alternatively, in accordance with yet other embodiments, the reservoir can be positioned below the one or more dispersion units and a pump used to provide sufficient water flow and pressure for distributing the rainwater onto the condensing coil from the one or more dispersion units.
• In accordance with some embodiments, the rainwater dispersed onto the condensing coil can be collected and returned to the reservoir.
• In accordance with still other embodiments, the process of regulating the amount of rainwater that is distributed by the one or more dispersion units onto the condensing coil can further include interpreting one or more sensors associated with the system to thereby determine when to distribute the rainwater onto the condensing coil (e.g., to determine whether or not the correct conditions are present for opening or closing the valve and/or for supplying electricity to the pump) and what quantity of rainwater is required to achieve the desired condensing temperature.
• This particular embodiment may include an apparatus for minimizing the effects of suspended solids in the rainwater such as a gutter leaf guard. Further, to minimize the effects of suspended solids in the rainwater, this embodiment may have filtration devices such as a barrier filter, a screen, a cartridge, a centrifugal separator, or a settling filter.
• In a different embodiment, a system for cooling refrigeration condensing coils is described. This particular system may have a reservoir for receiving and storing rainwater. The reservoir may be connected to liquid dispersion points by a conduit or series of conduits. Further, a controller can be electrically coupled to a controller and configured to distribute specific amounts of liquid to a liquid dispersion point. In this embodiment, the regulator could be a valve or a pump. Finally, the controller can have a plurality of sensors that are interpreted by the controller to determine appropriate amounts of liquid to distribute to the dispersion point.
• Other objects and benefits of the invention will become apparent from the following written description along with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
• The above-mentioned aspects of the present invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of the embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
• FIG. 1 is a flow diagram of an illustrative evaporative air conditioning heat transfer system in accordance with the teachings of the present disclosure and having an outdoor tank above ground;
• FIG. 2 is a flow diagram of an illustrative evaporative air conditioning heat transfer system in accordance with the teachings of the present disclosure and having an outdoor tank in ground with a pump;
• FIG. 3 is a flow diagram of an illustrative evaporative air conditioning heat transfer system in accordance with the teachings of the present disclosure and having an indoor tank above floor with a pump;
• FIG. 4 is a flow diagram of an illustrative evaporative air conditioning heat transfer system in accordance with the teachings of the present disclosure and having an indoor tank in floor with a pump;
• FIG. 5 is a heat balance flow diagram illustrating a conventional evaporatively modified air-cooled condensing unit that can be used in accordance with the teachings of the present disclosure;
• FIG. 6 is a heat balance flow diagram illustrating a conventional air-cooled condensing unit; and
• FIG. 7 is a heat balance flow diagram illustrating a conventional adiabatic air-cooled condensing unit; and
DETAILED DESCRIPTION
• The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.
• Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any method and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, illustrative methods and materials are now described.
• Generally speaking, the present application relates to systems and methods for retrofitting existing air-cooled condensers and condensing units (or new condensers or condensing units as would be designed by air conditioning unit manufacturers) to spray, sprinkle or otherwise distribute water over condensing coils (finned tube or other designs of air-cooled condenser coils) to lower condensing temperatures, thereby reducing power consumption. In accordance with certain aspects of the present disclosure, harvested rainwater can be used as an evaporation source, particularly as such water is free from dissolved minerals that typically foul and clog condenser coils.
• In terms of the means that may be used to spray water on an air-cooled condenser coil in accordance with the present disclosure, it should be understood and appreciated herein that there are various different known processes that can be used to wet the coil. While some of these conventional processes seek to minimize fouling of the coil with dissolved minerals while maximizing coil wetting, the present inventors have found a way to address these efforts by using mineral-free rainwater to wet a finned condenser coil. In fact, as many existing processes for spraying water on condenser coils have been unfavorably received due to excessive water usage (expensive) and condenser fouling in response to dissolved minerals that have precipitated out of the water, the presently disclosed methods are particularly useful for eliminating and overcoming these problems traditionally experienced by existing technologies.
• An Evaporative/Sensible Refrigeration/Air Conditioning Heat Transfer System (seeFIGS. 1,2,3 and4, for instance) (hereinafter known as ESRACHTS) utilizes rainwater (distilled water) to directly wet a standard, commercially designed and manufactured air-cooled, finned coil condenser which is integral to a condensing unit (a package unit that includes a compressor, perhaps a suction accumulator, condensing coil, condenser fan, and electrical safety and operating controls) that is typically the “outdoors” portion of a “split system” residential (and also small commercial) air conditioning system. Many of these “split systems” are also designed and operated as reverse cycle heat pumps (air-source). The reduction of the condensing temperature of an air conditioning or refrigeration system results in energy savings.
• Before going into specific details regarding the presently disclosed system, it should be appreciated herein that the ability to harvest rain (known as rainwater harvesting) and store it for use during times of air conditioning or refrigeration system operation, has significant application in residential, commercial, and industrial installations as a means to reduce energy usage and reduce peak electrical demand. The rainwater harvesting allows for the water that is distributed over the condensing surfaces to be mineral-free thus keeping the heat transfer surfaces clean.
• The various designs of condensers in an air-conditioning or refrigeration system can include of some of the following: extended-surface finned tube condensers; partially finned, partially bare tube prime surface condensers; all prime surface bare tube condensers; and plate condensers.
• The system for distributing water over the condenser coil can be a gravity water system or a low pressure nozzle spray type system. Moreover, the water source can be a rainwater harvesting tank positioned such that water can flow by gravity to a distribution system that will deliver the water over the condenser coil. Likewise, water can be pumped from a rainwater harvesting tank, reservoir or pit to a water distribution system located at the condenser.
• A simple control scheme that monitors condensing temperature and outdoor ambient air temperature can vary the water usage to achieve a desired condensing temperature while optimizing water usage. The control scheme can include a controller with a plurality of inputs, a logic board, and a plurality of outputs. The inputs into the control can include sensors that detect various temperatures throughout the system such as the condensing temperature and outdoor ambient temperature. Further, the controller can have outputs that can operate a regulator which could include either a pump or a valve. The logic board on the controller can analyze the inputs and determine whether certain conditions are justified to manipulate the regulator to supply varying amounts of water.
• The ESRACHTS system provides the energy efficiency that approximates that of water cooled and evaporatively cooled systems on standard residential and small commercial systems while not having to deal with the many maintenance and operational issues that are normally found in large water cooled and evaporatively cooled systems.
• One non-limiting advantage of the ESRACHTS System is that residentially (and on small commercial systems), lower condensing temperatures (and the inherent energy efficiency) are not commercially available at reasonable costs to homeowners or a small commercial businesses. This ESRACHTS System takes advantage of the evaporation of water to gain a lower condensing temperature—a concept that is currently only available to large commercial and industrial users who can devote the maintenance and service people and other resources necessary to own and operate large air conditioning and refrigeration plants. Residential customers do not have those resources. In short, air-cooled air conditioning and refrigeration systems tend to be simpler, less costly, and easier to operate than water cooled systems. Energy efficiency is normally sacrificed so as to achieve a low first cost and an ease of operation and maintenance.
• Harvesting of rainwater for evaporation on residential and small commercial system is a beneficial aspect of this present disclosure, particularly as it allows existing air conditioning and refrigeration equipment to undergo minimal and reasonable on-site modifications to implement an ESRACHTS System.
• Most water-cooled systems are of a recirculating type that require extensive scale and corrosion control water treatment procedures (chemical or non-chemical) in order to insure that the air conditioning equipment does not “scale-up” or corrode, causing it to lose efficiency and become unserviceable. The city water or well-water that is typically used for make-up water on large water-cooled systems are laden with many dissolved minerals, with Calcium Carbonate (CaCO3) being the most common and most troublesome.
• By way of example, a water-cooled system that is 100 tons in size (somewhat small for water-cooled systems) operates on an air conditioning system for 2,000 hours a year at a 40% load factor. The system consists of an evaporative cooling tower that cools condenser water serving a 100-ton water cooled chiller or 100 tons of self-contained water-cooled air conditioning units. Assuming that a water-cooled system operates at 0.75 KW per ton and that an air-cooled system operates at 1.30 KW per ton, the Energy Analysis of each system (0.75 KW per ton, water-cooled ton versus 1.30 KW per ton, air cooled) on a design summer day where the ambient dry bulb temperature is 95° F. and the coincident wet bulb temperature is 78° F. (these are considered to be design summer days for many locales throughout the United States, as published by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE)) can be determined as follows:
• AIR-COOLED 100 tons 1.3 KW/TR 2,000 annual operating hours, 40% load factor: 100×1.3×2,000×0.40=104,000 KWH annually. 104,000 KWH annual electrical usage at a rate (which includes both energy charge and demand charge) of $0.10 per KWH, the annual electric cost would be $10,400.
• WATER-COOLED 100 tons 0.75 KW/TR 2,000 annual operating hours, 40% load factor: 100×0.75×2,000×0.40=60,000 KWH annually. 60,000 KWH annual electrical usage at a rate (which includes both energy charge and demand charge) of $0.10 per KWH, the annual electric cost would be $6,000.
• A Water Quality Analysis is as follows: A water-cooled system takes advantage of the latent heat of water (approximately 1,000 BTU of heat removed per pound of water evaporated). Therefore, taking into account the heat of compression, a 100-ton chiller or self-contained water-cooled air conditioning units will need to typically reject 15,000 BTU/HR per ton of air conditioning.
• The amount of water that is evaporated by a cooling tower for a 100 ton unit is as follows: 100 ton×15,000 BTU/H-ton×1 lb. water/1,000 BTU=1,500 lbs. of water/hr.
• The quality of city and well water varies widely all over the United States and worldwide. This water quality, which is documented, can be as low as 50 to 75 parts per million (ppm) of calcium hardness and as high as 500 or 600 ppm. Any hardness greater than 200 ppm is considered to be “hard water,” while any water with less than 50 ppm of calcium hardness is considered to be “soft water.”
• For the sake of this example, and assuming a calcium hardness of 150 ppm, as well as ignoring water treatment techniques that are required for minimizing scale deposits and corrosion control that are mandatory with recirculating cooling tower systems, a 100 ton cooling tower will evaporate at peak load 1,500 pounds of water per hour. The dissolved mineral potential that will precipitate out of that water is calculated as follows: 1,500 lb./hr.×150 lbs. of CaCO₃/1,000,000 lbs. of water=0.225 lbs. of CaCO₃(scale). This is 0.225 lbs. of scale build up in one hour's time. If, on a design air conditioning day, the load was an average of 60 tons for 10 hours, the potential accumulation of scale would be calculated as follows: 60 ton×15,000 BTU/hr.-ton×1 lb. water/1,000 BTU×10 hour×150 lbs. of scale/1,000,000 lbs. of water. Total solids accumulation in one ten-hour day=1.35 lbs. of scale. This accumulation would be on the heat transfer surfaces (inside the tubes of a water-cooled condenser or the outside of the tubes of an evaporative condenser/cooler).
• Over an entire air conditioning season (100 tons, 2,000 annual operating hours, 40% load factor), the accumulation of scale could amount to as follows: 100 ton×0.40×15,000 BTU/hr.-ton×1 lb. water/1,000 BTU×2,000 hours×150 lbs. of scale/1,000,000 lbs. of water. Total annual scale accumulation=180 lbs. of scale for a 100 ton system operating at 40% load factor.
• As can be appreciated from considering the above example, water treatment is mandatory in order to sustain system efficiency and minimize corrosion. To this end, with regard to water treatment, bleed-off or blow down is a common technique to try to minimize scale build-up. If you bleed-off an amount of water equal to the evaporation rate (this is known as two cycles of concentration), the system would now be exposed to double the amount of dissolved minerals. Bleed-off is a form of dilution so as to not concentrate the minerals.
• With two cycles of concentration, the system would be exposed to 2.70 pounds of scale on a ten hour design day (as illustrated above) and also 360 pounds of scale on an annualized basis. Moreover, if a water treatment program is 95% effective in minimizing scale accumulation, 18 pounds of scale would accumulate annually. This amount of scale can still create a loss of efficiency and create maintenance and operating problems.
• All methods of trying to reduce the scaling tendency of water (water treatment, soft water, etc.) can be both costly and maintenance intensive. In addition, water cooled or evaporatively cooled systems using well water or city water is just not a viable option for residential and small commercial systems.
• Referring now toFIG. 1, an ESRACHTS system utilizes rainwater to wet an air-cooled finned or partially finned condensing surface so as to reduce the condensing temperature of an air conditioning or refrigeration system resulting in energy savings. In accordance with a firstillustrative ESRACHTS system100, rainwater can be harvested from a collection surface such as aroof102 or from a ground-level property drainage system and then collected in a storage tank orreservoir104 so as to provide mineral-free water to be used for evaporation for conventional air-cooledcondensing units106 on residential or small commercial buildings and facilities. As should be understood and appreciated herein, pure rainwater will be free of dissolved minerals thus allowing the harvested rainwater to be sprayed, sprinkled, or otherwise, distributed over a finned air-cooledcondensing coil108 without experiencing the precipitation of dissolved minerals that would result in the fouling of the finned condensing surfaces. Although harvested rainwater is absent of dissolved minerals, some suspended (non-dissolved) solids may need to be filtered from the rainwater, depending upon the configuration of the harvesting system. It should be understood and appreciated herein that the method and degree of filtration performed to minimize or eliminate the collection of suspended solids on the finned condensingcoil108 can be determined on an individual basis as desired and therefore is not intended to be limited herein.
• Inventive roof top rainwater collection systems such as is illustrated inFIG. 1 may utilize, but are not limited to the use of, one or more of the following in order to limit the introduction of suspended solids onto the finned condensing coils108: a) leaf screens; b) rainwater storage tank methods for settling solids out of a water stream; c) gravity centrifugal cyclone type separators; and d) cartridge or bag type filter units. However, in accordance with certain embodiments herein, a passive filtration process (e.g., solids settling, etc.) may be utilized in which the owner/user periodically hoses or sprays the condenser coils108 to dislodge any solids that may have collected. In accordance with one specific aspect of the present disclosure, the effects of suspended solids in the collected rainwater can be minimized by filtering the rainwater with a filtration device selected from a barrier filtration device, a screen, a cartridge, a bag, a centrifugal separator device and a settling filtration device.
• At peak air conditioning or refrigeration load, the water flow rate over thecondenser coil108 can be from about 1.5 to about 10.0 gallons per hour per ton depending upon the geometry of the coil and the specific characteristics of the air conditioning or refrigeration system under consideration.
• The evaporators of many air conditioning and refrigeration systems condense moisture out of the air as part of the dehumidifying effect of air conditioning. This condensed water is distilled water which is suitable for an ESRACHTS system. As seen inFIGS. 2 and 4, for instance, in accordance with certain aspects of the present disclosure, it is possible for the condensed water from the evaporator coil drain pan to be introduced into the rainwater storage tank (seereference numeral202, which illustrates this process), and particularly if the drain pan is located relative to thestorage tank204,404. According to this aspect of the present disclosure, the condensed water can then be used to supplement the water accumulated from rainwater.
• Referring once again toFIG. 1, since most air conditioning systems never operate at full load all of the time, the water flow rate over thecoil108 can be varied by use of a regulator device orcontrol valve110 that modulates in response to condensing (head) pressure. Because this water is mineral free, a variable water flow rate is allowed over the condensingcoil108. This modulatingcontrol valve110 can serve to conserve the accumulated rainwater and also help maintain a minimum head pressure on systems that require some external head pressure control. In accordance with certain aspects of the present disclosure, the regulator orcontrol valve110 can be positioned between thestorage tank104 and theliquid dispersion point112 where the condensing head or dispersion unit is configured to distribute rainwater onto the condensingcoil108. Moreover, in accordance with still other aspects of the present disclosure, regulating the amount or quantity of rainwater that should be distributed by one or more dispersion units onto the condensingcoil108 can be interpreted or determined by one or more sensors associated with theregulator110.
• Since proper wetting of the condensingcoil108 is essential to the energy efficiency inherent with evaporatively cooledcondensers106, existing condensing unit installations may require a modification in order to accommodatesprays112, gravity distribution troughs, etc. As manufacturers of air conditioning and refrigeration condensing units make design modifications (internal water piping and sprays, etc.) to their new units, installation of an ESRACHTS system will be much easier to implement.
• Properly designed air-cooled condensers have air flow rates and coil face velocities such that water carry-over (water being drawn through the fan122) should not create problems on existing installations. Again, proper water distribution over the coil prevents water carry over.
• The introduction of evaporative condensing to formerly air-cooled condensing will reduce the peak KW energy input per ton from 1.4 or 1.3 to 0.9 and possibly as low as 0.7 KW per ton. The specific energy reduction on existing condensing units is largely dependent upon the original design of the condensing unit (compressor type and efficiency, amount of condensing surface, condenser fan performance, etc.).
• Evaporative condensing achieved by wetting a finned air-cooledcondenser coil108 will reduce the design condensing temperature from a range of about 115° F. to about 130° F. to a range of about 90° F. to about 100° F. This reduction in condensing temperature and corresponding condensing pressure is the cause for the reduction in energy input to the compressor. As this reduction of condensing temperature and pressure becomes more commonplace, condensing unit manufacturers will design andsize condensing coils108 and compressors to operate more efficiently at these new operating conditions.
• These lower condensing temperatures at peak summer weather conditions (high dry bulb temperatures, high wet bulb temperatures, and high relative humidity) can benefit electrical utilities by lowering their peak demand.
• The illustrative ESRACHTS system configurations shown inFIGS. 1-4 provide flexibility for the arrangement and installation of such a system. These illustrations are merely provided to illustrate the various arrangements that may be utilized in accordance with the teachings of the present disclosure but are not intended to be limiting or all-inclusive in nature. Accordingly, those of skill in the art should readily understand and appreciate herein that several other different variations may also be utilized without straying from the teachings of the present disclosure, particularly as the basic ESRACHTS system concept is applicable to a multitude of installations. It will be incumbent upon the owner/purchaser/installer to follow the basic ESRACHTS system concepts to install a workable system to achieve the desired energy savings.
• Still referring to the illustrative embodiment ofFIG. 1,ESRACHTS system100 illustrateshouse roof102 having drains/gutters114 that collect all roof water drainage and allow it to be captured and stored in arainwater tank104 mounted on astand116 or elevated by some other method. Thiselevated tank104 can then allow rainwater to flow by gravity into the condensingunit106water distribution system112. This approach eliminates the need for a pump to deliver water over thecondenser coil108. Excess water in thecondensing unit106 can drain118 into the storm sewer, into a ditch, or be used for lawn watering, etc., as allowed by regulations. It should be understood and appreciated herein that one or more conduits (e.g., pipes, tubes) can be associated with the storage tanks or reservoirs for transferring liquid to the liquid dispersion points proximate the condensing coils. As such, the specific method or process utilized for transferring water from the storage unit to the dispersion unit is not intended to be limited herein.
• In accordance with another embodiment depicted inFIG. 2, anESRACHTS200 is illustrated with an in-ground storage tank204 with asubmersible pump206 to deliver water to thecondensing unit106water distribution system112. This system can allow for excess water to drain back202 to thestorage tank204. If arranged properly, additional rainwater could be delivered fromground sources208 into therainwater storage tank204. This in-ground storage tank204 is much like in-ground sewage tanks that are commonly used in many parts of the country.
• FIG. 3 illustrates yet another embodiment where anESRACHTS300 locates thestorage tank302 indoors above grade and requires apump304 to deliver the rainwater to thecondensing unit108distribution system112.
• A further embodiment shown inFIG. 4 illustrates anESRACHTS400 that locates thestorage tank404 below grade and even possibly in a basement. Apump402 is required to deliver the rainwater to thecondensing unit106distribution system112. Ground-level drains could convey the rainwater into thestorage tank404.
• In all cases, it is important that the rainwater storage tanks be vented to the outdoors120. However, the decision as to where the rainwater storage tank should be located and the size of the tank will be determined by the site-specific factors, and therefore is not intended to be limited herein.
• If the accumulation of rainwater is achieved through agutter114, it should be appreciated that some gutter and downspout modifications may be required so as to maximize the amount of rainwater that can be harvested. In addition, some systems may need to be drained in winter to avoid freezing damage, and it is recommended that all systems be cleaned at least twice a year (prior to air conditioning season and at the conclusion of air conditioning season) if the air conditioning is a seasonably operated unit.
• FIG. 5 depicts anESRACHTS system500 having a traditional air-cooledcondensing unit106. In accordance with this embodiment, theunit106 is fully functional in the event that insufficient rainwater has been accumulated due to drought, equipment failure, or human error. Accordingly, the system efficiency will be the same as the conventional air-cooled system. TheESRACHTS System500 is unique from other systems that might want to achieve low condensing temperatures, particularly since these systems do not use rainwater to wet a standard condensing coil to achieve low condensing.
• There are many non-limiting benefits of the ESRACHTS System. For instance, low condensing temperatures on residential air conditioning systems can approximate or be equal to the energy efficiency (low KW-per-ton) of large commercial or industrial air conditioning systems. Moreover, the use of mineral-free rainwater to facilitate the low KW-per-ton air conditioning systems is unique because large systems would require such an enormous volume of stored rainwater that such a system would not be feasible. To this end, the rainwater, without dissolved minerals, makes it feasible to achieve evaporative heat rejection with current, standard design air cooled condensers and condensing units. Additionally, since existing homes and residences already have a gutter and drain system to handle rainwater, modifications on a system-to-system basis may not require a significant expense to harvest and store rainwater.
• Many rainwater harvesting systems try to store and supply enough water that may be required for irrigation systems and domestic water supplies in areas that typically have insufficient water to sustain normal life. These rainwater harvesting systems can be massive and not feasible. However, harvesting enough rainwater to permit evaporative heat transfer for residences can be quite feasible.
• In the event of a drought or insufficient rainwater storage required for efficient air conditioning operation, the air conditioner will merely operate as air-cooled only, allowing for continued air conditioning albeit at a higher KW per ton than the ESRACHTS system.
• Existing large refrigeration systems will use evaporative condensers where water is sprayed over an all-prime surface (non-finned) condensing coil to permit low condensing temperatures. These systems will use a recirculating spray water system with make-up water being supplied from city water or well water systems. One-hundred percent rainwater is not a viable option due to the large volume of rainwater that would have to be harvested. Some evaporative condenser systems utilize wide-spaced finned coils so that dry operation of these condensers can be achieved during low ambient outdoor weather. Most of these systems (only a very few exist) operate unsuccessfully since the fins get scaled-up from the use of city or well water make-up—even in the presence of a good water treatment system.
• There are products that try to saturate the air adiabatically before that air reaches the finned condensing coil to avoid scaling (seesystem700 illustrated inFIG. 7). This system is fundamentally different from the ESRACHTS System. Again, the ESRACHTS system wets a standard copper-coil aluminum-finned condenser coil with mineral-free rainwater which thereby permits low condensing temperatures and low energy usage without scaling the finned condenser coil.
• On large commercial and industrial systems, the water usage for evaporation can far exceed a rainwater harvesting system's ability. As an example, a 500 ton water-cooled or evaporatively cooled system would require a peak water usage for evaporation of 15 GPM of water. For a 40% load factor, the monthly water usage for evaporation only would be 260,000 gallons. As an example, using rain fall averages from The National Oceanic and Atmospheric Administration (NOAA), 2.64 inches of rain will fall in Columbia, Mo. for the month of March. A 1,900 square foot home with a slanted roof can collect 2,500 gallons in the month. This size of home could equate to a 5-ton air conditioning load. By extrapolation, the amount of square footage required to accumulate 260,000 gallons of water (500 ton system) via rainwater harvesting would be nearly 200,000 square feet.
• This square footage of building area along with the infrastructure (rainwater tank size, guttering and piping to handle this volume of water) makes rainwater harvesting seem like an unworkable and virtually an impossible idea to be considered.
• Furthermore, if a water source other than rainwater were to be considered (well water or city water), the cost of pumping or purchasing that water and disposing of that water could be costly. Also, the treating of that water so as to minimize the effects of scaling of the condenser coil makes this an unworkable idea.
• Most existing technologies that are used to try to reduce condensing temperatures, residentially, (although not extensively) employ the adiabatic saturation of air700 (FIG. 7) to reduce the dry bulb air temperature entering a finned condenser coil on air conditioning systems. This method is used so that water will not directly come in contact with a finned condenser coil subjecting it to the scaling effect resulting from use of city or well water. However, the air saturating media can become scaled using city or well water and cause maintenance and operating problems. Likewise, overspray of this water will also scale and clog the condenser coil, which is an unintended consequence.
• The ESRACHTS System uses rainwater directly on a finned condenser coil allowing the refrigerant to give up its latent heat in condensing from a gas to a liquid while the mineral-free rainwater evaporates allowing the heat to dissipate into the air in the form of a vapor.
• FIGS. 6 and 7 are provided herein to illustrate the thermodynamics of conventional air cooled condensing600 andadiabatic condensing700. Unlike these traditional systems, the ESRACHTS System utilizes a unique configuration and process to lower condensing temperatures on residential and small commercial systems. For instance, taking the example of a 5 ton residence (1,900 sq. ft.) in Columbia, Mo. where 2,500 gallons can be accumulated in one month, at a peak summer cooling load of 5 tons and at a monthly average load of 50%, the monthly heat rejection would amount to: 5 tons×15,000 BTU/hr/ton×0.5×24 hours/day×30 days/month=27,000,000 BTU/month. The amount of water to be evaporated would be: 27,000,000 BTU/1,000 BTU/lb.=27,000 lb./month. This equates to 3,200 gallons per month of water to account for evaporation.
• In Columbia, Mo., a 1,900 sq. ft. house can accumulate 2,500 gallons. Therefore, a maximum storage volume to accommodate an extremely hot month could require a 3,000 to 4,000 gallon tank. As an example, a cylindrical tank8′ diameter×8′ tall would have a gross volume of 3,000 gallons.
• Although the primary focus of an ESRACHTS System is residential air conditioning and refrigeration, all of the concepts are applicable to larger commercial and industrial applications with the limitations being that of the ability to harvest and store the rainwater.
• While an exemplary embodiment incorporating the principles of the present application has been disclosed hereinabove, the present application is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the application using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this present application pertains and which fall within the limits of the appended claims.
• The terminology used herein is for the purpose of describing particular illustrative embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
• When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
• Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
• Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations).

Claims (20)

1. An evaporative air conditioning heat transfer apparatus comprising:

a collection surface for diverting liquid into a channel;

a reservoir capable of receiving and storing the diverted liquid;

at least one conduit for transferring liquid from the reservoir to a liquid dispersion point; and

a regulator positioned between the reservoir and the liquid dispersion point, the regulator being configured to control the amount of liquid released at the liquid dispersion point,

wherein the liquid dispersion point is configured to distribute the liquid over a condensing coil.

2. The evaporative air conditioning heat transfer apparatus ofclaim 1, wherein the regulator is a valve or a pump.

3. The evaporative air conditioning heat transfer apparatus ofclaim 1, wherein the collection surface is a roof.

4. The evaporative air conditioning heat transfer apparatus ofclaim 3, wherein the channel is a gutter.

5. The evaporative air conditioning heat transfer apparatus ofclaim 1, wherein the at least one conduit is a pipe.

6. The evaporative air conditioning heat transfer apparatus ofclaim 1, wherein the liquid is substantially mineral free rainwater.

7. The evaporative air conditioning heat transfer apparatus ofclaim 1, wherein the liquid dispersion point is positioned proximate the condensing coil.

8. The evaporative air conditioning heat transfer apparatus ofclaim 1, further comprising a controller that is configured to mechanically or electronically drive the regulator.

9. A method for cooling refrigeration condensing coils comprising:

collecting rainwater in a reservoir;

fluidly coupling the reservoir to one or more dispersion units;

distributing the rainwater from the one or more dispersion units onto a condensing coil of an air conditioning unit; and

regulating the amount of rainwater distributed by the one or more dispersion units onto the condensing coil.

10. The method ofclaim 9, further comprising positioning the reservoir above the one or more dispersion units to permit gravity to provide sufficient water flow and pressure for distributing the rainwater onto the condensing coil from the one or more dispersion units.

11. The method ofclaim 9, further comprising positioning the reservoir below the one or more dispersion units and using a pump to provide sufficient water flow and pressure for distributing the rainwater onto the condensing coil from the one or more dispersion units.

12. The method ofclaim 9, further comprising collecting and returning excess rainwater to the reservoir after the rainwater has been distributed onto the condensing coil.

13. The method ofclaim 9, wherein the step of regulating the amount of rainwater distributed by the one or more dispersion units onto the condensing coil comprises interpreting one or more sensors to determine when to distribute the rainwater onto the condensing coil.

14. The method ofclaim 9, wherein the step of regulating the amount of rainwater distributed by the one or more dispersion units onto the condensing coil comprises determining what quantity of rainwater is required to achieve a desired condensing temperature.

15. The method ofclaim 9, further comprising the step of minimizing effects of suspended solids in the rainwater.

16. The method ofclaim 15, wherein the step of minimizing effects of suspended solids in the rainwater comprises filtering the rainwater with a filtration device selected from a barrier filtration device, a screen, a cartridge, a bag, a centrifugal separator device and a settling filtration device.

17. A system for cooling refrigeration condensing coils comprising:

a reservoir for receiving and storing rainwater;

at least one conduit connected to the reservoir for transferring the rainwater to a liquid dispersion point; and

a regulator having a controller that is configured to distribute a specific amount of the rainwater over a condensing coil from the dispersion point.

18. The system ofclaim 17, wherein the regulator is a valve or a pump.

19. The system ofclaim 17, further comprising one or more sensors for determining when to distribute the rainwater over the condensing coil.

20. The system ofclaim 17, wherein the at least one conduit is a pipe.

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