Patent Application
20190063765
(Not applicable)
(Not applicable)
This invention relates generally to the field of refrigerators, freezers, ice makers, window or portable air conditioners and more specifically, it discloses a window, thru-wall or portable refrigeration device for food and/or indoor air.
According to U.S. Energy Information Administration (EIA) estimates in the Annual Energy Outlook 2017, the electricity consumption by the residential sector in the United States in 2016 was: 18% for space cooling, 7% for refrigeration, 2% for freezers, 9% for space heating and 9% for lighting. Air conditioners use about 6% of all the electricity produced in the United States, at an annual cost of about $29 billion to homeowners. As a result, roughly 117 million metric tons of carbon dioxide are released into the air each year. Furthermore according to EIA's web site, three-quarters of all homes in the United States have air conditioners and 30% of U.S. households have a second refrigerator.
Two of the warmest (and driest) cities in the U.S. are Phoenix Ariz. and Las Vegas Nev. where the highest daily maximum temperatures in June, July and August exceeds 100 F. According to US Climate Data website, the average highest temperatures for July and August in Phoenix is 105° F. (40.55 C) and the lowest is 83° F. (28.33° C.). That is a 22° F. (12.22° C.) temperature difference between average highest and lowest temperatures—primarily based on time of day (highest temperature) or night (lowest temperature).
As the outdoor temperature increases, power consumption increases and energy efficiency (of the refrigeration device) decreases. There are a number of different methods for evaluating air conditioner efficiency. The one that is most closely tied to physical principles is the coefficient of performance, or COP. The COP is the ratio of heat removed from a system to the energy required to remove the heat. The theoretical maximum is equal to the coldest temperature of the refrigerant divided by the difference between its coldest and hottest temperatures, where the temperatures are expressed in Kelvin.
Even the perfect system decreases in efficiency with increased outside temperature, dropping about 2 percent per degree Celsius (about 1 percent per degree Fahrenheit). In the real world, the drop in efficiency is even more dramatic; so it's not an illusion when your air conditioner seems to be working harder as the outside temperature increases. Therefore for Phoenix Ariz. (see 2 paragraphs up) during July & August the energy efficiency drops more than 24.4% operating the air conditioner during night or early morning hours (outdoor temperature ˜83° F.) than during day (˜105° F. usually around 3 PM). In other words, during July and August in Phoenix, operating a window air conditioner during night is >24% more efficient than during day.
According to FDA web site, the ideal temperature inside a refrigerator compartment is about 40° F. and inside the freezer compartment about 0° F. At temperatures between 0 and 32° F., food deteriorates more rapidly. Also the recommended thermostat setting for an air conditioner is 78 F.
Time programmable thermostats are available at Home Depot include for example Nest thermostat. With Nest thermostat target temperatures can be set on the hour or at 15-minute intervals—like at 7:00, 3:30, or 12:45. A time activated thermostat can control what hours to activate an evaporator for freezing ice (during colder hours, usually before sunrise) and when to deactivate it (for melting ice during warmer hours, usually during afternoon).
A ‘Fan Coil Unit’ (FCU) is a simple cooling device consisting of a heating or cooling coil and fan. It is part of an HVAC system found in residential, commercial, and industrial buildings.
The pipe is typically made of heat conducting material such as copper or aluminum. It receives hot or cold water and removes heat from or adds heat to the air through heat transfer. FCUs circulate hot or cold liquid or gas through a coil in order to condition a space. The hose, or ideally copper tubing (pipe) is wound around in a spiral at the back or front of the air fan, so the air drawn into or out of the fan is cooled (or heated) to below (or above) the ambient summer (or winter) air temperature. Antifreeze fluid or heavily salted water is often used as the coolant pumped around the system through the coil to prevent freezing. Any circulation pump (like aquatic or fluid pump) can be used to move the coolant around the system through the coil.
Depending upon the selected chilled water temperatures and the relative humidity of the space, it is likely that the cooling coil will dehumidify the entering air stream, and as a by product of this process, it will at times produce a condensate which will need to be carried to drain. The fan coil unit (FCU) will contain a purpose designed drip tray with drain connection for this purpose.
Fan coil units are divided into two types: Two-pipe fan coil units or four pipe fan coil units. Two-pipe fan coil units have one supply and one return pipe. The supply pipe supplies either cold or hot water to the unit depending on the time of year. Four-pipe fan coil units have two supply pipes and two return pipes. This allows either hot or cold water to enter the unit at any given time.
In addition, there are portable air conditioners that have their condenser exposed to outside the desired cooling area or outdoor air through a flexible air duct that is attached to a window (or an opening through the wall) enabling the condenser coil to exchange heat (expel hot air) through the air duct to outside the desired cooling area or outdoor air.
Phase change materials are substances that absorb and release thermal energy during the process of changing phase (for example melting and freezing). When a phase change material freezes, it releases a large amount of energy in the form of latent heat at a relatively constant temperature. Conversely, when such material melts, it absorbs a large amount of heat from the environment. phase change materials recharge as ambient temperatures fluctuate, making them ideal for a variety of everyday applications that require temperature control.
The most commonly used phase change material is water/ice. Ice is an excellent phase change material for maintaining temperatures at 0° C. But water's freezing point is fixed at 0° C. (32° F.), which makes it unsuitable for most thermal energy storage applications.
To address that limitation, phase change materials have been developed for use across a broad range of temperatures, from −40° C. to more than 150° C. They typically store 5 to 14 times more heat per unit volume than materials such as water, masonry or rock. Among various heat storage options, phase change materials are particularly attractive because they offer high-density energy storage and store heat within a narrow temperature range.
This invention is a combined thru-wall, window or portable refrigeration device that uses the temperature difference between day and night to efficiently cool air. It saves electricity by using phase change material such as for example water-ice to solidify the phase change material at night or early morning hours and it lets the phase change material melt during day. Its condenser coil can at least periodically exchange heat with outside the desired cooling area or outdoor air (outside). The refrigeration device may include a refrigerator, a freezer, an icemaker or an indoor air conditioner.
The refrigeration device has one or more thermal conducting pipes (tubes or hoses) made of for example copper or aluminum. One or more water pumps circulate thermal conducting antifreeze fluid inside the pipes. The pipes run between a reservoir that contains thermally conducting phase change material and one or more air fans blowing cold air into indoor space or into a refrigerator, a freezer or an icemaker compartment.
A first portion or section of the pipe meanders (zigzags, twists and turns or coils) in the reservoir to maximize heat exchange with the phase change material inside the reservoir. A second portion of the pipe meanders (zigzags, twists and turns or coils) in front or behind the air fan to intercept the air blown by the air fan and to maximize heat exchange between the pipe and the air blown by the fan. Instead of the second portion of the pipe meandering in front or behind the fan, the second portion can be directly connected to a commercially available fan coil unit for enabling efficient exchange of heat between the reservoir and the air blown by the fan coil unit.
A time activated thermostat controls the operation of an evaporator coil to produce a solidified phase change in the phase-changing material in the reservoir at night or during early morning hours before outdoor temperature rises. As the outdoor temperature rises during day time, the time activated thermostat shuts off the evaporator coil allowing the solidified phase-change material to gradually melt. The cold melting phase change material is used for cooling air during day when outdoor temperature is hot.
The melting phase change material inside the reservoir keeps the pipes cold, enabling cooling of the inside of the refrigerator (freezer or ice maker depending on the temperature of the phase change material) or indoor air with the fan coils without using electricity during warmer day time hours (usually around 3 PM) while the refrigeration cycle (evaporator, condenser, compressor, motor) is off.
An alternative embodiment may include the refrigeration device heating indoor space during winter. For heating indoor space, a separate heat conducting pipe (with heat conducting fluid circulating therein by a fluid pump) runs between a heat source and the fans blowing air indoors (into the home). The pipe transfers heat from the heat source to the same air fans used during summer for cooling indoor space.
This refrigeration device may also be (or sold as) a standalone refrigerator, a standalone freezer, a standalone ice maker, a standalone air conditioner or a combination of all or some of the above. If it's a standalone ice maker, the ice compartment may serve a dual function, as an ice dispenser and as a water/ice reservoir (phase change material reservoir) that is frozen (phase change) during night or early morning hours before temperature rise (to conserve energy). After the temperature rises (in the afternoon, usually around 3 PM), some or all of the ice is melted (phase change) for cooling inside the refrigerator or indoor air.
Furthermore, the refrigerator, freezer, ice box or phase change material reservoir can be positioned in any order. For example the freezer compartment may be at the bottom instead of on top of the refrigeration device. Since the pipe can be extended (made longer) the section of the pipe running between the reservoir and the fans may be insulated to reduce heat loss during heat exchange between the reservoir and the air fans.
Some objects and advantages of the present invention include:
1) Saves indoor space, convenient, compact.
2) Costs less to buy & maintain than a separate refrigerator, freezer, ice maker and air conditioner.
3) Saves electricity by running the motor and compressor (doing most of the work) when outdoor temperature is lower (instead of higher) and there is low demand on electric grid. The energy saving is even more significant in dry climate areas (like southwest US) with significant temperature difference between day (warm) and night or early dawn (cool).
Or alternatively the same size motor and compressor can cool a larger cubic feet of indoor space.
4) Can be used all year round as a refrigerator, a freezer or an ice maker.
5) Saves electricity during winter by using outdoor air for cooling inside of the refrigerator.
6) During summer, it shifts electricity consumption from peak to off-peak hours of demand on the electric grid or provides additional cooling power during hot summer days (usually around 3 PM).
7) Like air conditioner, it can dehumidify indoor air and works well in warm humid climate.
8) In winter it can heat indoor air using the same air fans used during summer for cooling indoor air. Thus saving space.
9) A disadvantage of portable air conditioner is that its portability is restricted by an air duct that during operation must be attached to the condenser to expel hot air emitted by condenser coil outside the cooling area (see
Applicant's portable air conditioner only at night to sunrise, when outdoor is relatively mild and often air conditioner is not used, is attached to an air duct or directly to a window or an opening through the wall to expel hot air produced by the condenser coil outside the desired cooling area or outdoor. During hot day time hours (usually in the afternoon) when air conditioning is most needed, it can be moved to any location that cooling is needed and used without an air duct connecting the condenser to outside the desired cooling area. That is because the compressor, evaporator and condenser are deactivated. During hot day time when air conditioning is activated only the air fan and the pump run. Furthermore the air fan can be outside the unit and in that case an internal air duct is not needed thereby reducing size, weight, manufacturing, shipping and product cost.
10) Applicant's refrigeration device can cool indoor air without an internal (inside the refrigeration device) air fan or internal air duct. This reduces size, shipping and manufacturing cost. Damp dirty air ducts inside the air conditioner, are hard to clean, may cause allergies and contribute to indoor air pollution. Also unwanted insects may hide and nest inside.
Other objects and advantages will become apparent from the following descriptions, examined in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.
One fan coil 10 (towards outside, right side) pulls hot outside air into the air duct 17 and the second fan coil 10 (towards indoors, left side) ejects cold air out of the air duct 17 into indoor space. The arrows indicates the direction of air flow generated by the fan coil 10. There is another fan coil 10 inside the refrigerator compartment 300, ejecting cold air into the refrigerator compartment 300. All 3 fan coils 10 may use the same pipe 11 or each using a separate pipe 11. Antifreeze or heavily salted water can be used as the liquid coolant pumped around the system through the pipe 11. Any circulation pump (like aquatic pump, not shown) can be used to move the coolant (antifreeze fluid) around a loop through the pipe 11.
In operation, during summer nights (when outdoor is colder than during day), an evaporator coil (not shown) cools the phase change material reservoir 50 to freeze the phase change material (for example freeze water to ice) inside the reservoir 50, cooling the pipe 11 zigzagging, twisting inside the phase change material reservoir 50. During the day, when the fan coil 10 inside the refrigerator is turned on, the chilled pipe 11 meandering or coiling in front of the air fan 12 (forming a fan coil 10) cools the air blown into the refrigerator compartment 300.
Similarly, during hot summer days, the user will turn on the air cooler. That opens the two gates (louvers or shutters) 30 at both ends of the air duct 17 connecting indoor to outside air and also turns On (activates) the two fan coils 10 at the two ends of the air duct 17. The hot outside air entering the air duct 17 loses some of its heat to the chilled pipe 11 meandering or coiling in front of the air fan 12 (forming a fan coil) and cools the air blown indoors. As shown there is a thick insulation 60 between the freezer 200 (normally at around 0 F) and the air duct 17 to prevent the freezer compartment 200 gaining heat due to its proximity to the air duct 17.
Optionally a fluid pipe connector 47 may enable the user to disconnect the outside portion of the pipe 11 so that it can be removed during cold seasons when air cooling is not needed. In this case the antifreeze fluid inside the pipe 11 must first be drained. To remove the outside portion of the pipe, the pump circulating antifreeze in the pipe must be turned off. Then the air inlet valve or vent 49 is opened so that the antifreeze can drain into an antifreeze container (not shown) under the pipe. The antifreeze container can be inside the reservoir 50, it can be outside the reservoir 50 or near it. Alternatively, the connector 47 may be hinged (or a small section of the pipe 11 at the connector location made of flexible material such as plastic) to allow the pipe 11 to lay or bend horizontally on top of the refrigeration device when cooling of indoor air is not needed.
A big disadvantage of portable air conditioners is that their portability is restricted by an air duct 17 that during operation must be attached to the condenser 92 to expel condenser coil's hot air outside. Applicant's portable air conditioner only during night to sunrise (when outdoor is cold and often air conditioner is not used) is attached to an air duct to expel hot air produced by the condenser coil outside.
During hot day time hours (usually in the afternoon) it can be moved (rolled) to any location that cooling is needed and used without an air duct (can run ductless). It can be moved while cooling (the only needed attachment is the electric wire). It can run wirelessly (without electric wire) if the needed power is stored by a battery during night when the portable air conditioner is not used and the phase change material is being solidified.
Most window air conditioners have built-in fans (inside the refrigeration device) which generally have smaller surface area and are weaker than ordinary household air fans. Not having a built-in fan, not only reduces manufacturing cost but also enables the user to buy a separate more powerful air fan or use an existing air fan.
This embodiment of invention also works well with a conventional indoor refrigerator (with the condenser coil exchanging hot air with indoor air rather than outdoor. In this case, the air fan 11 on top of the refrigeration device pulls air from behind the refrigerator where the condenser coil usually is located. As a result air ventilates the fridge's condenser coil, cooling the condenser coil and thereby increasing energy efficiency of the indoor refrigerator.
While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
This invention is an improvement to my U.S. Pat. No. 9,080,801 and my pending patent application Ser. No. 14,728,656 and two U.S. Provisional Patents 62/441,690 dated Jan. 3, 2017 and 62/380,985 dated Aug. 29, 2016.
