Patent Description:
In a heat pump system, because the amount of refrigerant required in a refrigeration cycle and a heating cycle are different, a receiver is often provided. The receiver can store excess refrigerant during the heating cycle and release refrigerant in the refrigeration cycle for use by the system.

For a multi-function heat pump system, such as a heat pump system with three units, the conventional two-pipe receiver can only be connected between two units, so that in some modes, the receiver cannot function to store or release refrigerant. In addition, if the receiver which stores the refrigerant is not connected to a thermal cycle, the receiver will form a dead zone, and the refrigerant in it cannot be used for system operation.

<CIT> discloses a heat pump apparatus with a main bypass line extending from a refrigeration circuit, and provided with an pressure valve, such that any excess fluid in the refrigeration circuit is directed through the pressure valve, and through the bypass line, to a tank for storing the excess fluid.

Document <CIT> discloses a receiver assembly for a heat pump system, according to the preamble of claim <NUM>.

According to a first aspect of the invention as defined in claim <NUM>, a heat pump system is provided, which comprises a receiver assembly for use in a refrigeration system. The receiver assembly comprises: a receiver; and a first pipe and a second pipe leading to the receiver, wherein, the receiver assembly further comprises: a third pipe connected between the first pipe and the second pipe, wherein a first check valve and a second check valve are provided on the third pipe, and the first check valve and the second check valve only allow fluid to flow from the first pipe to the second pipe. The receiver is placed upright, and the first pipe and the second pipe extend to the bottom of the receiver; or the receiver is placed upside down and the first pipe and the second pipe are disposed at the bottom of the receiver and do not extend to the top of the receiver.

Optionally, in the receiver assembly, the first pipe connects to a first load unit and the second pipe connects to a second load unit, and a connection point for a cold and heat source unit is provided between the first check valve and the second check valve on the third pipe.

Optionally, in the heat pump system, the first load unit and/or the second load unit are selected from an air conditioning unit, a hot water generating unit, a floor heating unit, and a refrigerator cabinet unit.

Optionally, in the heat pump system, the first load unit is a refrigerator cabinet unit, and the second load unit is an air conditioning unit.

Optionally, in the heat pump system, the cold and heat source unit comprises a compressor, a switching device such as a four-way valve, a heat exchanger, and a throttling device. The receiver and the cold and heat source unit may be integrated in a same outdoor unit housing, or arranged separately.

Optionally, in the heat pump system, the heat pump system can operate in one, multiple, or all of the following modes:.

Optionally, in the heat pump system, in the fifth mode, the refrigerant passes from the second load unit through the second pipe, the receiver and the first pipe, and flows to the first load unit.

According to another aspect of the invention as defined in claim <NUM>, a method for connecting a receiver is further provided. The method comprises:.

The method may involve the receiver or receiver assembly described above, such as within a heat pump system as described above.

The receiver structure according to the embodiments of the present invention may be applied to a heat pump system with three or more units, so that the receiver can function in more modes.

With reference to the drawings, the disclosure of the present invention will become easier to understand. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes, and are not intended to limit the scope of protection of the present invention. In addition, similar numerals in the figures are used to denote similar components, among which:.

<FIG> shows a conventional arrangement of a receiver in a refrigeration system having three units. The refrigeration system comprises: a cold and heat source unit <NUM>, a first load unit <NUM> and a second load unit <NUM>. Generally, a receiver <NUM> can be, for example, arranged outdoors together with the cold and heat source unit <NUM>, or can be arranged separately from the cold and heat source unit <NUM> (for example, arranged together with the first load unit <NUM> or the second load unit <NUM>). When the refrigerant flows from the cold and heat source unit <NUM> to the first load unit <NUM> and/or the second load unit <NUM>, it will pass through the receiver <NUM>. The system can, for example, be operated in a heat recovery mode in which one of the first load unit <NUM> and the second load unit <NUM> refrigerates and the other heats. At this time, the refrigerant will directly flow from one of the first load unit <NUM> and the second load unit <NUM> to the other without passing through the receiver <NUM>. At this time, the receiver <NUM> becomes a dead zone in the system. If a relatively large amount of refrigerant is stored in the receiver <NUM>, it may cause a lack of refrigerant in the operating parts of the system, i.e., between the first load unit <NUM> and the second load unit <NUM>.

A proposed receiver assembly <NUM> is described in detail with continued reference to <FIG>. The receiver assembly <NUM> comprises a receiver <NUM>, and several pipes and valves. In an embodiment, the receiver assembly <NUM> can be integrated with the cold and heat source unit <NUM> in an outdoor unit, for example, a common housing is provided to accommodate the cold and heat source unit <NUM>. The cold and heat source unit <NUM> may be an outdoor unit, which may comprise components such as a compressor, a switching assembly (such as a four-way valve), a heat exchanger, a throttling device (such as an expansion valve), a gas-liquid separator, and so on.

As shown in detail in the enlarged view of <FIG>, the receiver assembly comprises: a receiver comprising a first pipe <NUM> and a second pipe <NUM> leading to the receiver, and a third pipe <NUM> connected between the first pipe <NUM> and the second pipe <NUM>. A first check valve <NUM> and a second check valve <NUM> are arranged in sequence on the third pipe <NUM>. The first check valve <NUM> and the second check valve <NUM> are connected in series. The first check valve <NUM> and the second check valve <NUM> only allow fluid to flow from the first pipe <NUM> to the second pipe <NUM>, more specifically, only allow fluid to flow from a connection point P of the third pipe <NUM> and the first pipe <NUM> to a connection point Q of the third pipe <NUM> and the second pipe <NUM>. In some embodiments, the first pipe <NUM> is used to connect to a first load unit <NUM>, for example, a first pipeline <NUM> is connected to the first pipe <NUM> and to the first load unit <NUM>. Similarly, the second pipe <NUM> is used to connect to a second load unit <NUM>, for example, a second pipeline <NUM> is connected to the second pipe <NUM> and to the second load unit <NUM>. In some embodiments, the cold and heat source unit <NUM> is connected between the first check valve <NUM> and the second check valve <NUM> on the third pipe <NUM>. More specifically, a third pipeline <NUM> is connected between the first check valve <NUM> and the second check valve <NUM> on the third pipe <NUM> and to the cold and heat source unit <NUM>. The receiver assembly <NUM> realizes the application of the receiver in various modes among three units only through several pipes and check valves. For example, in the case where the first load unit <NUM> refrigerates only, the refrigerant from the cold and heat source unit <NUM> passes through the third pipeline <NUM>, the second check valve <NUM>, the second pipe <NUM>, the receiver <NUM>, the first pipe <NUM> and the first pipeline <NUM> in sequence, and then flows to the first load unit <NUM>. In the case where the second load unit <NUM> refrigerates only, the refrigerant from the cold and heat source unit <NUM> passes through the third pipeline <NUM>, the second check valve <NUM> and the second pipeline <NUM> in sequence, and then flows to the second load unit <NUM>, and the receiver <NUM> connects to the second pipeline <NUM> through the second pipe <NUM>, so the receiver <NUM> can store or release refrigerant through a separate second pipe <NUM>. In the case where the second load unit <NUM> heats only, the refrigerant flows reversely from the second load unit <NUM> through the second pipeline <NUM>, the second pipe <NUM>, the receiver <NUM>, the first pipe <NUM>, the check valve <NUM> and the third pipeline <NUM> in sequence, and returns to the cold and heat source unit <NUM>. In addition, in the case where the first load unit <NUM> and the second load unit <NUM> refrigerant at the same time, the refrigerant from the cold and heat source unit <NUM> passes through the third pipeline <NUM>, and divides into a first portion and the second portion after passing through the second check valve <NUM>, wherein the first portion of the refrigerant is delivered to the second load unit <NUM> through the second pipeline <NUM>, and the second portion of the refrigerant passes through the second pipe <NUM>, the receiver <NUM>, the first pipe <NUM> and the first pipeline <NUM> in sequence, and flows to the first load unit <NUM>. At this time, the receiver <NUM> is connected in the cycle and can store or release refrigerant. In the case where the first load unit <NUM> refrigerates and the second load unit <NUM> heats, the refrigerant flows from the second load unit <NUM> to the first load unit <NUM> to recover part of the heat, and the refrigerant flows from the second pipeline <NUM> through the second pipe <NUM>, the receiver <NUM>, the first pipe <NUM> and the first pipeline <NUM>, and is then delivered to the first load unit <NUM>. Therefore, it is appreciated that the receiver assembly <NUM> according to the embodiments of the present invention can function in any of the aforementioned five modes.

Although the above description is based on units with five operating modes, specifically, the operating modes comprise: a first mode in which the first load refrigerates and the second load shuts down; a third mode in which the first load shuts down and the second load refrigerates; a fourth mode in which the first load shuts down and the second load heats; a fifth mode in which the first load refrigerates and the second load refrigerates; and a seventh mode in which the first load refrigerates and the second load heats. However, according to the actual situations of the load units, the refrigeration system may only operate in some of the above five modes. These do not affect the functions of the receiver assembly <NUM>.

In some embodiments, as shown in the figure, the receiver <NUM> is placed upside down. At this time, the gravity of the refrigerant can be used to assist the release of the refrigerant in the receiver, and the first pipe <NUM> and the second pipe <NUM> are disposed at the bottom of the receiver, and do not extend to the top of the receiver. In other embodiments, the receiver in the refrigeration system is placed upright. At this time, the first pipe <NUM> and the second pipe <NUM> need to extend to the bottom of the receiver <NUM>.

In some embodiments, the first load unit <NUM> and/or the second load unit <NUM> may be selected from any one of an air conditioning unit, a hot water generating unit, a floor heating unit, and a refrigerator cabinet unit. In some embodiments, the first load unit <NUM> may be a refrigerator cabinet unit. Since the refrigerator cabinet unit generally only operates in the refrigeration mode, and is in a state of multiple units connected in parallel and being turned on and off at irregular intervals, based on this characteristic, the refrigerator cabinet unit is connected to the first pipeline <NUM>, so that the receiver <NUM> can provide sufficient refrigerant to ensure the refrigeration demand of the refrigerator no matter when the refrigerator cabinet unit has a refrigeration demand. In some embodiments, the second load unit <NUM> may be an air conditioning unit. Connecting the air conditioning unit to the second pipeline <NUM> allows the receiver <NUM> to possess the function of adjusting the circulation amount of the refrigerant in the system.

In addition, a method for connecting a receiver is further provided, which comprises: connecting a first pipe and a second pipe of the receiver through a third pipe, wherein a first check valve and a second check valve are provided on the third pipe, and the first check valve and the second check valve only allow fluid to flow from the first pipe to the second pipe, and wherein the receiver is placed upright, and the first pipe and the second pipe extend to the bottom of the receiver, or the receiver is placed upside down and the first pipe and the second pipe are disposed at the bottom of the receiver; connecting the first pipe to a first load unit, connecting the second pipe to a second load unit, and connecting a cold and heat source unit between the first check valve and the second check valve on the third pipe.

The devices and method according to the embodiments of the present invention realize the application of the receiver in various modes only through the design of the receiver itself or the design of the connecting flow paths of the receiver and several check valves, in which no complicated control logic is involved, and a good stability is presented. In addition, the products according to the embodiments of the present invention can be easily implemented without adding excessive costs, and can also be used for simple transformation of existing systems.

Claim 1:
A heat pump system comprising:
a receiver assembly (<NUM>) for use in a refrigeration system, comprising:
a receiver (<NUM>); and
a first pipe (<NUM>) and a second pipe (<NUM>) leading to a cavity of the receiver (<NUM>), wherein, the receiver assembly (<NUM>) comprises: a third pipe (<NUM>) connected between the first pipe (<NUM>) and the second pipe (<NUM>), wherein a first check valve (<NUM>) and a second check valve (<NUM>) are provided on the third pipe (<NUM>), and the first check valve (<NUM>) and the second check valve (<NUM>) only allow fluid to flow from the first pipe (<NUM>) to the second pipe (<NUM>);
characterised in that:
the receiver (<NUM>) is placed upright, and the first pipe (<NUM>) and the second pipe (<NUM>) extend to the bottom of the receiver (<NUM>); or the receiver (<NUM>) is placed upside down and the first pipe (<NUM>) and the second pipe (<NUM>) are disposed at the bottom of the receiver (<NUM>) and do not extend to the top of the receiver (<NUM>).