(12) United States Patent (10) Patent No.: US 8,181,474 B2

Transcription

1 US B2 (12) United State Patent (10) Patent No.: US 8,181,474 B2 Chen (45) Date of Patent: May 22, 2012 (54) SOLAR-POWERED AIR CONDITIONER RE34,542 E * 2/1994 Rockenfeller , USING AMIXTURE OF GLYCERIN, 5, , 1994 Tokizaki et al / ,525,251 6/1996 Hammond /70 ALCOHOL AND WATER TO STORE ENERGY 5,811,025 A * 9/1998 Kawai et al /70 5,878,584. A 3/1999 Saaki et al ,115 (76) Inventor: Chengjun Julian Chen, White Plain, 6, B1 * 1 1/2002 Malach /70 NY (US) 6, B1* 2/2003 Kopko ,539,738 B2 * 4/2003 Gonzalez-Cruz et al / ,880,553 B2 4/2005 Liu et al (*) Notice: Subject to any diclaimer, the term of thi 7,062,923 B2 * 6/2006 knet al patent i extended or adjuted under 35 7,645,331 B2 * 1/2010 Yang et al /1441 U.S.C. 154(b) by 600 day. 2003/ A1* 5/2003 Caell et al / A1* 5/2007 Yang et al / , A1* 10, 2009 Marinho et al , (21) Appl. No.: 12/479, / A1* 12/2009 Chen... 62/235.1 (22) Filed: Jun. 8, 2009 * cited by examiner (65) Prior Publication Data Primary Examiner Cheryl J Tyler Aitant Examiner Paolo Gonzalez US 2009/ A1 Dec. 10, 2009 (57) ABSTRACT Related U.S. Application Data A Solar-powered air conditioning ytem including an (63) Continuation-in-part of application No. 12/135,113, energy-torage medium made of a mixture of 5%-20% glyc filed on Jun. 6, 2008, now Pat. No. 7,543,455. erin, 2.5%-10% alcohol and water in a thermally inulated container i dicloed. While frozen, the aid energy torage (51) Int. Cl. medium become lurry of thin heet of ice dipered in F25B 27/00 ( ) liquid, which will not damage the container and the heat (52) U.S. Cl /235.1; 62/59; 62/434 exchange pipe. The ytem ue a Solar photovoltaic panel to (58) Field of Claification Search... 62/59,235.1, directly drive a vapor-compreion refrigeration unit to freeze 62/434, 435; 126/400; 165/10; 252/70 the aid energy torage medium. A ventilation ytem force See application file for complete earch hitory. air through a heat-exchange coil in the aid energy-torage medium, to generate chilled air to cool the pace. In the (56) Reference Cited abence b of f unli Sunlight, the h energy-torage 9. medium can keep U.S. PATENT DOCUMENTS 4,237,964 A * 12/1980 Larue et al , ,823,864 A * 4, 1989 Rockenfeller / ,237,832 A * 8/1993 Alton frozen for day. With or without unlight, the flowing air chilled by the frozen energy-torage medium continue to cool the room or the entire building. 7 Claim, 2 Drawing Sheet R C-C Cro Section N. S N x: S& ex & 8xxxxxXxxx S. &&

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4 1. SOLAR-POWERED AIR CONDITIONER USINGA MIXTURE OF GLYCERIN, ALCOHOL AND WATER TO STORE ENERGY CROSS REFERENCE TO RELATED APPLICATIONS Thi i a continuation in part to U.S. patent application Ser. No. 12/135,113, entitled Solar-Powered Refrigerator Uing a Mixture of Glycerin, Alcohol and Water to Store Energy', filed Jun. 6, 2008, to be iued a U.S. Pat. No. 7,543,455 on Jun. 9, BACKGROUND OF THE INVENTION Cooling of building conume a huge amount of energy worldwide. For example, in the Sunbelt State of the US, including Alabama, Arizona, California, Florida, Georgia, Louiiana, Miiippi, Nevada, New Mexico, South Caro lina, and Texa, air conditioning i the dominant end uer of energy and the ingle leading caue of peak demand for electricity. From an economic point of view, reducing elec tricity demand for pace cooling could ave a lot for conum er. From a utility-infratructure point of view, reducing air conditioning electricity load can lower demand for annual power generation and peak capacity. Coincidentally, in region where air conditioning i needed the mot, Solar energy i alo abundant. Epecially, from day to day, the tronger the Sunlight, the more air conditioning power i needed. Therefore, to utilize unlight to power air condition ing i a logical Solution. Air conditioner uing olar energy have been dicloed, for example, in U.S. Pat. No. 5,375,429, 5,878,584, 6,539, 738, and 6,880,553. There i a common drawback of thoe method: Solar energy i only available in Sunny day, not in evening and night. By directly uing the Solar electricity to drive an air-conditioning unit to cool the room, it doe not provide a relatively contant temperature throughout the entire day and night. Right after Sunet, when the environ ment i till very hot, the Solar power diappear. And the maximum cooling effect from direct Sunlight i at noon time, which i not the hottet time of the day (the hottet time in a day i about 3-5 pm). In the evening and night, although air conditioning i till needed, there i no Sunlight. Sunlight i alo abent in cloudy and raining hour. To reolve thi problem, method to tore cooling power uing ice have been dicloed in the 1980, with the purpoe of taking advantage of the price difference of electricity in peak time and night, motly for large commercial building. On the other hand, for the cooling of vehicle and boat, the ue of ice a a torage method for cold energy wa dicloed in U.S. Pat. No ,832 and 7, The problem with thoe approache i that when water i frozen to ice, the Volume increae by 9%, and the expanding ice could damage the container and the heat-exchange coil. For air condition er in building, the amount of ice i a good fraction of one ton or more than one ton, and the potential damage to the con tainer and tube can be ignificant. During the reearch for patent application Ser. No. 12/135, 113, it i found experimentally that by freezing a mixture of 10% of glycerin, 5% of alcohol and 85% water, thin heet of ice are formed, and the pecific gravity of the ice heet are imilar to that of the liquid. In other word, with a proper compoition, there i no ignificant expanion during freez ing. A a reult, the ice heet do not tay at the top of the container. Intead, the ice heet dipere over the entire volume. Mechanically, thoe thin heet of ice are fragile and US 8,181,474 B mobile, which will not damage the container a well a the tube. Therefore, uch mixture are uitable to ue a cold energy torage for air conditioner. The preent invention i related to a deign of a Solar powered air conditioning ytem which utilize the DC cur rent directly from the olar cell to drive a vapor-compreion refrigeration unit to freeze a mixture of glycerin, alcohol and water (typically 5%-10% of glycerol, 2.5% to 5% of alcohol, and 85%-90% of water), then ue the tored cooling power of the partially frozen glycerin-alcohol-water mixture to cool the building. Becaue the low cot of crude glycerin and indutry-grade alcohol, the elimination of the inverter and power ditribution facilitie, and the implicity of the appa ratu, the Solar-powered air conditioning ytem could have a ignificant impact on energy aving. BRIEF SUMMARY OF THE INVENTION The current invention i a Solar-powered air conditioning apparatu uing an efficient, afe and inexpenive medium to tore energy. It utilize the DC current from olar cell to drive a vapor-compreion refrigeration unit directly, bypaing the inverter and power grid. It utilize a mixture of glycerin, alcohol and water to tore cooling energy. The cooling coil of the refrigeration unit i placed in a container filled with uch an energy-torage medium, thu to freeze it into thin heet of ice dipered in an aqueou olution of glycerin and alcohol. Experiment howed that with by freezing a mixture of 10% of glycerin, 5% of alcohol and 85% water, thin heet of ice are formed, and the pecific gravity of the ice heet are imilar to that of the liquid. The ice heet do not tay at the top of the container. Intead, the ice heet dipere over the entire volume. Mechanically, thoe thin heet of ice are fragile and mobile, which will not damage the container a well a the pipe. On the other hand, the latent heat of the ice heet i a large a regular ice, which i 80 calorie per gram, or 335 kilojoule per kilogram. A tream of air i paing through a et of heat exchange pipe in the partially frozen energy torage medium, and then circulate by a fan or a blower to cool the pace. Uing a thermotat, the temperature can be regulated, imilar to ordinary air conditioning unit. Mixture of water and glycerin a cold energy torage media for packaging were dicloed previouly. For example, in U.S. Pat. No. 6,482,332, it wa dicloed that a mixture of 90% water and 10% glycerin melt at about -2 C. to -7 C.; and a mixture of 80% water and 20% glycerin melt at about -6 C. to -14 C. Thoe energy torage media, uually pack aged in platic bag, are ueful for keeping food frozen. However, the purpoe of that Patent i to lower the freezing temperature of water for the torage of frozen good. On the other hand, in the preent patent application, the purpoe of mixing glycerin and alcohol to water i to improve the mechanical propertie of the energy-torage media for air conditioner. Lowering the freezing point i not the purpoe. For example, ince the mot comfortable temperature of the room are around 20 C. or 68 F., an energy torage medium of freezing point between 0 C. and 10 C. can be ued. However, hard and expanding ice i not uitable for Such application. A an apparatu in a reidential home oran office, afety i a major conideration. Both glycerin and alcohol are popular food ingredient and commonly ued kin-care liquid; there fore it i very afe, epecially at a low concentration. In addition, both glycerin and alcohol are not corroive, which will not caue deterioration of the container and heat-ex change pipe.

5 3 Cot i an important factor for the viability of a product. Decade ago, glycerin wa fairly expenive. In recent year, a glut of crude glycerin exit a a byproduct of biodieel. The market price of crude glycerin i S0 to S150 per metric ton. The impuritie in crude glycerin are mainly rock alt, water, alcohol and reidual fat, which are not toxic. Therefore, crude glycerin can be directly ued without purification. Indutry grade alcohol i alo inexpenive. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B how a olar-powered tand-alone air conditioning ytem. FIGS. 2A and 2B how the baic component of a olar powered central air-conditioning ytem. DETAILED DESCRIPTION OF THE INVENTION FIGS. 1A and 1B how the baic component of a olar powered tand-alone air-conditioning ytem for a ingle room. Solar panel 101 i intalled either on a outh-facing roof or a outh-facing awning, and the Solar-generated DC current power a motor 102. Preferably, the motor 102 i directly coupled to the compreor 103 of a vapor-compre ion refrigeration unit, 103 through 109. The compreor 103 compree the refrigerant through pipe 104 into condener 105. Here, a fan 106 dipere the heat of the compreed refrigerant into air. The fan 106 i driven through the belt and wheel 107, alo powered by motor 102. After condening, through pipe 108, the refrigerant i let to expand by the expanion valve 109. The expanded refrigerant i going through a thermally inulated pipe 110 into a heat-exchange coil 111 to freeze the energy-toring medium 112, a mixture of glycerin, alcohol and water, in a thermally inulated con tainer 113. The air in the room flow through the heat-ex change tube 114, and cooled by the energy-toring medium 112. The air i handled in an encloure 115 with a eparation wall 116. The warm air i flowing through the heat-exchange tube 114, driven by an electric fan 117. Fin 118 can be ued to change the direction of wind. The C-C cro ection dia gram further clarifie the relation among the heat-exchange coil 111, the energy-torage medium 112, the inulated con tainer 113 and the heat-exchange tube 114. Becaue the frozen mixture of glycerin, alcohol and water i made of very thin heet of ice, and it pecific gravity i imilar to that of the liquid, it would not damage the container and the heat exchange coil. FIGS. 2A and 2B how the baic component of a olar powered central air-conditioning ytem. Solar panel 201 i intalled either on a South-facing roof or a South-facing awning, and the Solar-generated DC current power a motor 202. Preferably, the motor 202 i directly coupled to the compreor 203 of a vapor-compreion refrigeration unit, 203 through 209. The compreor 203 compree the refrig erant through pipe 204 into condener 205. Here, a fan 206 dipere the heat of the compreed refrigerant into air. The fan 206 i driven through the belt and wheel 207, alo pow ered by motor 202. After condening, through pipe 208, the refrigerant i let to expand by the expanion valve 209. The expanded refrigerant i going through a thermally inulated pipe 210 into a heat-exchange coil 211 to freeze the energy toring medium 212, contained in a thermally inulated tank 213. The air i flowing through the heat-exchange tube 214, and cooled by the energy-toring medium 212, into the air handling ytem through duct 215 and 216. A in the con ventional central air conditioning ytem, the air handling ytem comprie a fan or a blower, a thermotat, and fin to US 8,181,474 B control the temperature and the peed of airflow to the room. The returning air from the room i going through duct 215 and then cooled again by the heat-exchange tube 214. The C-C cro ection diagram further clarifie the heat-exchange coil 211, the energy-torage medium 212, the inulated con tainer 213 and the heat-exchange tube 214. Again, becaue the frozen mixture of glycerin, alcohol and water i made of verythin heet of ice, and it pecific gravity i imilar to that of the liquid, it would not damage the container and the heat-exchange coil. For practical reaon, here we make an etimate of how much energy-torage medium i required. For the cae of a relatively large ingle room, uing tandard inulation, if the outide temperature i 30 C., to maintain a room temperature of 20 C., the rate of heat lo i 200 W. Each hour, the energy lo i 720 kj. If the ma of the thermal-torage medium i 100 kg, auming one half of the ma i frozen to ice, the latent heat i 1.67x10 kj, and the thermal-torage medium can maintain the temperature for 24 hour. For an entire houe, for example, equivalent to five relatively large room, a 500 kg thermal-torage medium could maintain the tem perature for 24 hour. For financial reaon, the ize of Solar panel i etimated a follow. Suppoe the coefficient of performance (COP) of the refrigerator i 3-5, to freeze one half of the 100 kg glyc erin-alcohol-water mixture in 5 hour, a power of 180 W to 300 W i required. If the price of olar cell i one dollar per watt, the cot of olar cell i S180 to S300. Auming that the efficiency of olar panel i 20%, the area of olar cell i 0.9 quare meter (10 Square foot) to 1.5 quare meter (16 Square foot). For a central air conditioning ytem, the cot of olar cell could be five time higher: 0.9 kw to 1.5 kw with a cot of $900 to $1500 and an area of 50 to 80 quare foot. Com paring with the aving of electricity, the cot i reaonable. An important iue i the tranportation and intallation of the thermal-torage medium. Becaue water i available any where, the factory could upply an empty container and a mixture of glycerin and alcohol. For a ingle room, the required quantity of glycerin and alcohol i le than 20 lb, which can be hipped in two one-gallon platic bottle. At the ite, glycerin and alcohol i mixed with water in the container. For an entire houe, the required quantity of glycerin and alcohol i le than 100 lb, or ten one-gallon platic bottle. What i claimed i: 1. A Solar-powered air conditioner compriing: an energy-torage veel filled with a mixture of glycerin, alcohol, and water a an energy torage medium which become a lurry of thin heet of ice dipered in liquid while frozen; a olar photovoltaic panel for generating electric power from Sunlight; a motor driven by DC electricity generated by the olar photovoltaic panel; a vapor-compreion refrigeration unit driven by the Solar powered motor to freeze the energy torage medium; a et of heat exchange coil in the energy torage veel to generate chilled air by the frozen or partially frozen energy torage medium; a fan or a et of fan to ditribute the chilled air to a pace to be cooled. 2. The apparatu of claim 1 wherein the energy torage medium comprie water with 5% to 20% of glycerin and 2.5% to 10% of alcohol. 3. The apparatu of claim 1 wherein the alcohol comprie methanol, ethanol, iopropyl alcohol and imilar alcohol.

6 5 4. The apparatu of claim 1 wherein the fan or et of fan i controlled by a thermotat to keep a temperature of the pace to a preet value. 5. The apparatu of claim 1 wherein the energy-torage veel i located in a room to be cooled and the fan i directly connected to the energy-torage veel. 6. The apparatu of claim 1 wherein the energy-torage veel i located in a place eparated from the pace to be US 8,181,474 B2 6 cooled and the et of fan and duct are ued to ditribute the chilled air to the pace to be cooled. 7. The apparatu of claim 1 wherein the energy-torage veel i located in a baement of a building and the et of fan and duct are ued to ditribute the chilled air to room of the building.