Patent Publication Number: US-2021190330-A1

Title: Window-type air conditioner

Description:
TECHNICAL FIELD 
     The invention relates to an air conditioner. In particular the present invention relates to a split air-conditioner configured to be installed in a window. 
     BACKGROUND 
     Air conditioning is a collective expression for conditioning air into a desired state. It could be heating the air during cold periods, cooling the air during warmer periods or for cleaning the air if it contains unwanted particles. However, the expression air conditioning is most often used when emphasizing cooling. As a product, air conditioners can look and be used in various ways, but they all share the same basic technology. The air-conditioner comprises a compressor, a condenser, an evaporator, and typically also an expansion device. 
     There are different types of air-conditioners. One type of air-conditioner can be referred to as a split air-conditioner. In a split air conditioner, the condenser and the evaporator are located in two different separated units that are interconnected via pipes to circulate a refrigerant from one unit to the other. 
     Another type of air-conditioner can be referred to a Packaged Air Conditioner. A Packaged Air Conditioner (AC) can be said to be a type of self-contained system, in which all the cooling cycle components, such as the compressor, condenser, expansion device, evaporator and control system are enclosed in a single package. Among the packaged systems, the most commonly used for residential applications are the Window-type ACs, Packaged Terminal AC&#39;s (PTAC), and also Portable AC units. 
     The Packaged Air Conditioner has the advantages of easy installation, relatively small footprint, flexibility for heating/cooling individual rooms and low cost. 
     In contrast, Split Air Conditioners comprise at least two factory-made separated assemblies, designed to be used together. In a split system, the outdoor unit is separated by some distance from the indoor one(s) by means of semi rigid pipes which contain the refrigerant (at high pressure well above atmospheric pressure) that produces the cooling/heating effect in the system. Among other advantages, split systems can provide high efficiency ratios in a wide range of capacities and working conditions. Additionally, in split AC systems, the compressor, outdoor heat exchanger and outdoor fan can be located further away from the inside space, rather than merely on the other side of the same unit (as in PTACs or window air conditioners), achieving lower indoor noise levels. 
     Some disadvantages of the Split ACs are their higher price and their additional installation costs, since in most of the cases it is required qualified personnel to execute a proper installation. This issue can be especially critical because of the technical limitations for the users to manipulate specific working fluids like HFC-refrigerants, commonly used in Air Conditioning applications. EP 0468576 describes a type of air-conditioner with a portable AC where the excess heat and water can be removed using a water based hose system to an outside unit comprising a heat exchanger. 
     There is a constant desire to improve air conditioners. Hence, there exists a need for an improved air conditioner. 
     SUMMARY 
     It is an object of the present invention to provide an improved air-conditioner. 
     This object is obtained by an air conditioner as set out in the appended claims. 
     In accordance with the invention an easy to install air-conditioner is provided. The air-conditioner can be said to be a type of split air-conditioner comprising an outdoor unit that includes a complete refrigeration system. The cooling/heating of the outdoor unit is then circulated indirectly via an energy transport medium to the indoor unit. The air-conditioner is particularly suited for installation in a window opening. 
     In accordance with a first aspect of the invention an air conditioner configured to be installed in a window is provided. The air conditioner comprises an indoor unit and an outdoor unit. Further provided is a piping system that interconnects the indoor unit with the outdoor unit. The indoor unit comprises an indoor heat exchanger for cooling or heating air in the indoor unit. The outdoor unit comprises a compressor, a first outdoor heat exchanger, such as a liquid-to-refrigerant heat exchanger, and second outdoor heat exchanger, such as an air-to-refrigerant heat exchanger. The compressor is configured to drive a refrigerant via the first outdoor heat exchanger and the second outdoor heat exchanger in a refrigerant circuit. In addition, the piping system is configured to circulate an energy transport media from the first outdoor heat exchanger to the indoor heat exchanger. Hereby a compact, robust air conditioner suited for window installation is obtained. The energy transport media can be circulated at low pressure whereby connection of the indoor unit and outdoor unit can be made easy. Also, all noisy and bulky components can be located in the outdoor unit, which improves the indoor environment. 
     In accordance with one embodiment, the energy transport media is a water based solution such as water or water with some additive. Hereby an easy to handle energy transport media that is user-friendly can be used in the circulating system that cools (or heats) the indoor air. 
     In accordance with one embodiment, a main pump is provided in the indoor unit to circulate the energy transport media. Hereby an efficient circulation of the energy transport media is obtained and the pump is easy to access for maintenance. 
     In accordance with one embodiment, a liquid tank is connected to the piping system. Hereby, liquid can be filled to the piping system in an easy manner. 
     In accordance with one embodiment, the liquid tank is located at a top position of the piping system. The liquid tank can be provided with a one-way valve. Hereby, an efficient filling that can be obtained that keeps air out from the piping system when the system is in use. 
     In accordance with one embodiment, a box is located under the indoor heat exchanger for collecting condensate water. Hereby condensate water can be collected by a user. 
     In accordance with one embodiment, an arrangement for pumping condensate water from the indoor unit to the outdoor unit is provided. Hereby condensate water that for example can be collected by the box can be ejected to the outside and does not need to be taken care of by a user. 
     In accordance with one embodiment, the piping system comprises a connection device. The connection device can advantageously be located on the top part of the outdoor unit. Hereby an easy connection of the indoor unit and outdoor unit can be obtained. This can facilitate installation or de-installation when the indoor unit and out-door unit are separated. 
     In accordance with one embodiment, an arrangement for switching the air-conditioner between a cooling mode and a heating mode is provided. Hereby the air-conditioner can be made to cool air inside when the inside air is warm and to heat air inside when the inside air is cold. 
     In accordance with one embodiment, at least one heat exchanger in the outdoor unit is made of aluminum. Hereby a light construction of the outdoor unit can be obtained. 
     In accordance with a second aspect of the invention, an indoor unit of an air conditioner configured for window installation is provided. The indoor unit can comprise a liquid to air heat exchanger and a low-pressure circuit. In particular the low-pressure circuit can be configured to operate at around 1 bar. The low-pressure circuit passes through the liquid to air heat exchanger. The low-pressure circuit comprises at least one connector adapted to connect the indoor unit to an outdoor unit. Hereby, an easy to use indoor unit for a window installed air-conditioner is provided that takes little space and which does not produce any or very little noise. 
     In accordance with a third aspect of the invention, an outdoor unit of an air conditioner configured for window installation is provided. The outdoor unit comprises a packaged refrigeration system comprising a compressor, a liquid-to-refrigerant exchanger, and an air-to-refrigerant heat exchanger. The compressor is configured to drive a refrigerant via the air-to-refrigerant heat exchanger and the liquid-to-refrigerant heat exchanger in a refrigerant circuit. The liquid-to-refrigerant exchanger is configured to cool or heat an energy transport media circulated from an indoor unit. Hereby, an easy to use outdoor unit for a window installed air-conditioner is provided that comprises many of the noisy and bulky components of the air-conditioner. Also, all the components of the refrigeration circuit are located in the outside unit so there is no risk of hazardous refrigerant leakage inside. 
     In accordance with one embodiment the refrigerant circuit is factory sealed. Hereby, there is no need for a user to engage in handling the refrigerant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described in more detail, by way of example, and with reference to the accompanying drawings, in which: 
         FIG. 1  shows a general view of an AC installation in a window opening, and 
         FIG. 2  illustrating a detailed exemplary embodiment of an Air-conditioner as shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. For example, like or similar components of different embodiments can be exchanged between different embodiments. For example, the system as described herein is described as a cooling system, but the cooler can equally be a heater if the system is run in a heating mode. Some components can be omitted from different embodiments. Like numbers refer to like elements throughout the description. 
     As has been realized by the inventor, conventional air-conditioners of a split type are difficult and often expensive to install. Also, a system such as the one described in EP 0468576 requires the compressor, and all components of the refrigeration circuit, including the refrigerant, to be located in the space where cooling is to take place. This will add to space requirement of the indoor unit and also there will be a significant level of noise resulting from the operation of the compressor. Further, the refrigerant remains inside of the space to be conditioned, which is negative in case of leak of refrigerant. It would therefore be advantageous to provide a modified split air-conditioner that can be easily installed and that can provide an indirect-cooling air conditioner working with an external packaged refrigeration system. 
       FIG. 1  shows a schematic diagram of an embodiment of an air-conditioner  100 . The air-conditioner  100  can be said to be of a split type with an indirect cooling system comprising an indoor unit  101  and a packaged outdoor cooling unit  102 . The units  101 ,  102  are interconnected via an intermediate piping system  103 . The piping system  103  and can advantageously use an energy transport media that is safe to use such as an aqueous solution. For example, water or water with some additive can be used as an energy transport media. Further, a mechanism  104  for installation of the air conditioner  100  is depicted. Also depicted is a window  105  where the air-conditioner  100  is installed. In this exemplary embodiment the window  105  is a standard hung type window. The air conditioner as described herein can also be installed in other type of windows such as a sliding window or some other openable window. Thus, the cooling system comprises a packaged refrigeration system mounted outside in an outdoor unit  102 , an indoor unit  101  installed inside and a circuit that connects both units, which contains an energy transport media. The energy transport media can be at atmospheric pressure. The system can also be operated in another mode where the system is configured to heat the indoor unit. The indoor unit  101  will then be used as a heater. 
     In  FIG. 2 , an exemplary implementation of the split type air-conditioner  100  of  FIG. 1  is shown in more detail.  FIG. 2  shows the indoor unit  101 , and the outdoor unit  102 . The indoor unit comprises an air-to-liquid heat exchanger  203 . The air-to-liquid heat exchanger  203  cools (or heats) the air flowing in the indoor unit  101 . Further, a liquid-to-refrigerant heat exchanger  204  is provided in the outdoor unit  102 . The liquid-to-refrigerant heat exchanger  204  works as evaporator. Further a main pump  205  is provided to circulate a liquid solution used as an energy transport media from the indoor unit  101  to the outdoor unit  102  (and back again). The main pump can also be  3 o located in the outdoor unit  102 . The liquid solution is circulated via the piping system  103 . In this example the connection system  103  is formed by two connection pipes  206  and  207 . Since, the piping system  103  can be made to work at relatively low pressure (around 1 bar), the pipes  206  and  207  can alternatively be hoses or similar devices that are easy to handle and can be provided with connectors that can withstand a low pressure. The outdoor unit  102  further comprises a refrigeration system, comprising a compressor  216  driving a refrigerant via that an air-cooled heat exchanger  215  via an expansion valve  220  and the heat exchanger  204  back to the compressor  216 . The refrigeration system of the outdoor unit can be factory installed such that the user or installer does not have to work with the circuit circulating the refrigerant. The refrigerant circulated via the air-cooled heat exchanger  215  can then be filled in the factory. There will then be no need to handle a refrigerant during installation, because the refrigerant circuit of the outdoor unit  102  is factory sealed. 
     Further, a liquid tank  208  can be located on the top of the system. The liquid tank  208  can be connected to the circuit circulating the energy transport media. In accordance with one example the liquid tank can be connected to the suction port of the main pump  205 . The tank  208  can include a level sensor  209  for controlling the amount of liquid solution circulated between the indoor unit  101  and the outdoor unit  102  needed for proper operation of the system  100 . A box  210  can be provided under the indoor heat exchanger  203  for collecting any condensate that is generated on the indoor heat exchanger  203 . A sensor  211  can be provided to detect the water level inside of the condensate box  210 . The sensor  211  can generate a signal that can be used to control a condensate water pump  212 . When activated the water pump  212  is adapted to pump water from the box  210  to outside of the indoor unit  101 . In particular water can be pumped outside of the building where the indoor unit is mounted to be released on the outside. Hereby an arrangement that can pump condensate water from the indoor unit  101  to the outside is obtained. 
     In accordance with some embodiments the water is pumped to the outside unit  102 . The pumped water can then for example be pumped through a drainage line  213  towards a spray device  214  located on the top of the outdoor air-cooled heat exchanger  215 , which is connected to the compressor  216 .  FIG. 2  further depicts a fan  221  provided in the indoor unit  101  for circulating air in the indoor unit. Also, a fan  222  is provided in the outdoor unit for circulating air in the outdoor unit  102 . The piping system  103  can further be provided with a connection device  218 . The connection device  218  can for example be a quick connection to in a quick and safe manner interconnect the piping of the indoor unit  101  with the piping of the outdoor unit  102 . The connection device  218  can advantageously be located on the top part of the outdoor unit for easy access. By connecting the indoor unit  101  with the outdoor unit  102 , an energy transport media can be circulated between the indoor unit  101  and the outdoor unit  102 . Also, condensate water can be transported from the indoor unit to the outdoor unit  102  via the piping system  103 . 
     In use, the air conditioner  100  decreases the temperature of the energy transport media using the external packaged AC device of the outdoor unit  102 . The cooling capacity of the outdoor-unit  102  is then transported in to the indoor unit  101  via the piping system  103 . The cooling capacity is then delivered using the low-pressure air-to liquid heat exchanger  203  of the indoor unit  101 . Heat is then returned from the inside unit  101  to the outside unit  102  by returning the energy transport media to the outside unit when having being heated in the indoor unit  101  that is installed in the indoor space to be conditioned. Because the cooling capacity is isolated to the outdoor unit  102  all heavy and noisy components can be confined to the outside unit and the indoor environment can be close to free of noise. Also, there is very little space required for the indoor unit. Because the piping system  103  used to transfer heat between the indoor unit  101  system can be a low-pressure system it can use an energy transport media that is easy to handle, such as water a water based solution, or some other liquid media such as ethanol. 
     Thus, in accordance with some embodiments, an aqueous media can be used to transport the energy from the indoor space to be conditioned to the evaporator located in the external packaged device. The main pump  205  will ensure the flow of the energy transport media by pumping the aqueous media, and the external cooling unit will reject the heat generated in the process to the ambient outdoor air. This is made possible since the external, packaged cooling system located in the outdoor unit can comprise all the  3 o standard constitutive elements in a refrigeration system, such as compressor, condenser, expansion device, evaporator and control system, and refrigerant. In accordance with some embodiments the liquid to refrigerant heat exchanger  204  can be a light brazed plate heat exchanger or a coaxial-type heat exchanger. The liquid to refrigerant heat exchanger  204  can be made of aluminium to make the weight low. The air-to-refrigerant heat exchanger  215  can be a micro channels heat exchanger or a fins &amp; tubes air cooled heat exchanger. The material of the micro channel heat exchanger and or the fins and tube heat exchangers can be Aluminum, and/or aluminum &amp; copper. 
     By using the system as set out herein, the refrigeration system becomes very small, given the possibility to decrease its size and weight, so facilitating its installation through a window in a residence. Additionally, by having such a compact system with a secondary circuit transporting energy between the indoor unit and the outdoor unit using an energy transport media, the installation will not need to be permanent, and it can be easily removed and reinstalled in different places any number of times according to the convenience of the user. This can be made without having to handle the refrigerant of the external packaged cooling system. 
     The liquid tank  208  placed on the top of the indoor unit  101  can be provided with an internal one-way valve (not shown). By providing the liquid tank  208  at a highest position of the piping system and providing the one-way valve at the liquid tank filling of the piping system with water or any other energy transport media used, can be made once the installation has been done. The positioning of the liquid tank  208  and the one-way valve allows in turn the elimination of the air from the system. This ensures a proper operation of the air-conditioner, and prevents problems like galvanic corrosion due to interaction between e.g. an aqueous solution and oxygen from air. 
     In accordance with one embodiment, the external packaged cooling system can be provided with a 4-way valve (not shown) in the refrigerant to enable a switch in the direction of the refrigerant flow, allowing the system to work as a heat pump device for winter conditions. Hereby an arrangement is provided whereby the air-conditioner can be switched between a cooling mode and a heating mode. In the heating mode, the energy transport media will introduce the heat generated in the external packaged cooling device of the outdoor unit  102 , to circulate to the indoor unit  101  to heat the indoor space where the indoor unit  101  is located. 
     While it is possible to use any energy transport media to transport energy between the indoor unit  101  and the outdoor unit  102  via the connection system  103 , the use of an aqueous solution as energy transport fluid offers the advantage of being innocuous and safe for the user. Further there is no need to pressurize the media in the connection system  103 , since it can work at a relatively low pressure, in particular at or near atmospheric pressure. Hereby, the connections of the connection system  103  interconnecting the indoor unit  101  with the outdoor unit  102  can be made less complex compared to systems using pressurized gases above atmospheric pressure. 
     The present invention offers all the advantages of a standard split AC, in terms of performance, low noise, reliability, but adding versatility and flexibility to the installation process. It also solves the problem of the high initial investment, normally associated to the additional installation cost of standard split AC&#39;s.