Heat pump system

Abstract

The present invention relates to a heat pump system that comprises a heat exchanger unit located in a first enclosure (41) and equipped with a first latent heat exchanger (1) and at least one sensible heat exchanger (3, 4). Said sensible heat exchanger is configured and arranged to receive, before the first latent heat exchanger (1), the gaseous refrigerant from a compressor (5) at the same time that it receives a first air flow (31a - 31d) and preheats or reheats it depending on its use, using the sensible heat of the refrigerant before it passes through the first latent heat exchanger (1).

Description

[0001] DESCRIPTION

[0002] HEAT PUMP SYSTEM

[0003] Object of the invention

[0004] A first object of the present invention relates to a heat pump system that can operate exclusively on its primary energy source, completely dispensing with the additional support of an electric heater or other heat sources, and can continue to operate within the same inlet and / or outlet airflow temperature ranges in heating mode. A second object of the present invention relates to a heat pump system that enables defrosting without having to shut down or reverse the operating cycle.

[0005] Background of the invention

[0006] Heat pump systems are known in the state of the art that use an additional heat source (e.g. an electric resistor) to support their main energy source during their heating working mode, either to increase the temperature of the inlet air flow when the outside ambient temperature is excessively low or to increase the temperature of the outlet air flow and achieve a higher heating temperature range.

[0007] However, these heat pump systems with additional heat support involve high electricity costs and low energy efficiency (the electrical power consumed ends up being greater than the heat output). Therefore, there is a need for a completely autonomous heat pump system that continues to operate within the same inlet and / or outlet airflow temperature ranges as conventional systems.

[0008] Description of the invention

[0009] A first objective of the present invention is to provide a heat pump system which, being suitable for working in conventional heating mode and in conventional cooling mode, is also capable of working in heating mode with inlet air at a range of temperatures so low that a conventional heat pump could not work without additional heat support external to the thermodynamic circuit (generally that of an electric resistance), and / or capable of pumping air at a range of temperatures so high that a conventional heat pump could not work either without said additional support.

[0010] The present heat pump system is of the type comprising: an inverter type compressor configured and arranged to, when the heat pump system operates in heating mode, compress a refrigerant (for example R410A, propane, HFCs, etc.) received in gas state, increasing its pressure and temperature, a first enclosure provided with a first fan configured and arranged to generate a first air flow that passes through the first enclosure from its inlet to its outlet, a heat exchange assembly housed in the first enclosure, the heat exchange assembly being configured and arranged to, when the heat pump system operates in heating mode, receive the refrigerant in gas state coming from the compressor, the heat exchange assembly being provided with at least a first latent heat exchanger configured and arranged to produce a mainly latent heat transfer (i.e.,all or a large part of the refrigerant changes state) from the refrigerant to the first air flow, causing condensation of the first air flow, an expansion valve (preferably electronic) configured and arranged to, when the heat pump system operates in heating mode, reduce the pressure of the refrigerant coming from the first latent heat exchanger, a second enclosure provided with a second fan configured and arranged to generate a second air flow that passes through the second enclosure from its inlet to its outlet, a second latent heat exchanger housed in the second enclosure, the second latent heat exchanger being configured and arranged to, when the heat pump system operates in a heating mode,receive the refrigerant in liquid state from the expansion valve and produce a transfer of heat mainly latent from the second air flow (32a - 32b) to the refrigerant, producing the evaporation of the refrigerant, (that is, the refrigerant heats up and goes into gas state when working in heat, latent exchange).,

[0011] The heat pump system of the first object of the present invention is characterized in that the heat exchange assembly comprises at least one sensible heat exchanger configured and arranged to receive the refrigerant in gas state coming from the compressor prior to the first latent heat exchanger, while also receiving the first air flow also prior to the first latent heat exchanger and increasing its temperature (preheating or reheating it depending on the application) only by sensible heat of the refrigerant (that is, without there being a change of state from liquid to gas).

[0012] At least one sensible heat exchanger is designed so that the amount of heat energy exchanged between the refrigerant and the first incoming air flow does not exceed the amount at which the refrigerant would begin to condense. In other words, the dimensions, geometry, and physical parameters of the heat-transferring components of the sensible heat exchanger are suitable so that the refrigerant, which reaches the compressor discharge temperature, only transfers to the first air flow the heat energy corresponding to the sensible heat of the high-pressure circuit, and that the first incoming air flow reaches the minimum temperature necessary for the refrigerant to condense and evaporate in the compressor's operating area.

[0013] In a first embodiment, at least one sensible heat exchanger is configured and arranged to receive the first air flow prior to the first latent heat exchanger. This allows the first and second inlet air flows to be at the same temperature (for example, if the entire system is exposed to the elements) and the compressor does not stop, unlike what would happen to conventional heat pumps without the additional support of an electric heater or any other type / source of heat.

[0014] In a second embodiment compatible with the above, at least one sensible heat exchanger is configured and arranged to receive the first air flow downstream of the first latent heat exchanger. Thanks to this, the heat pump system manages to heat the first air flow 20°C or more above the condensation temperature of the refrigerant (for example, with R410A gas, this is typically around 60°C, so the first air flow can reach temperatures above 80°C without the additional support of an electric heater or any other type / source of heat).

[0015] In a preferred embodiment, for when it is not necessary for at least one sensible heat exchanger to work, the heat pump system comprises: a main valve, for example, of the solenoid or 3-way type, configured and arranged to control the passage of refrigerant from the compressor directly to the first latent heat exchanger, at least one secondary valve, for example of the solenoid type, configured and arranged to control the passage of refrigerant from the compressor to the at least one sensible heat exchanger, a control system configured and arranged to control the opening and closing of the main valve and of the at least one secondary valve, and at least one check valve (a check valve being understood as a valve with a check, non-return or similar function),configured and arranged so that the refrigerant coming from the at least one sensible heat exchanger or the one coming from the main valve is directed towards the first latent heat exchanger and does not flow back towards the at least one sensible heat exchanger.

[0016] In this way, the control system can close the at least one secondary valve so that the refrigerant bypasses the at least one sensible heat exchanger and goes directly to the latent heat exchanger.

[0017] Preferably, the heat pump system comprises: a first sensible heat exchanger configured and arranged to receive the first air flow prior to the first latent heat exchanger, a second sensible heat exchanger configured and arranged to receive the first air flow after the first latent heat exchanger, a first secondary valve and a second secondary valve configured and arranged to control the flow of refrigerant from the compressor to respective sensible heat exchangers, two valves with a check function configured and arranged so that the refrigerant coming from respective sensible heat exchangers is directed towards the first latent heat exchanger.

[0018] In this latter embodiment, the heat pump system is capable of operating, in its heating mode, with a first incoming airflow at a temperature below that required for the refrigerant to condense and evaporate in the compressor working area, while being capable of providing a first outgoing airflow at a temperature 20°C or more above the refrigerant condensation temperature.

[0019] In a possible embodiment, the first enclosure and the second enclosure are integrated into a single block or casing (i.e., the heat pump system is monobloc).The heat pump system of the second object of the present invention, which is of the same type as and compatible with the heat pump system of the first object, is characterized in that it comprises: a bypass valve, for example of the solenoid type, configured and arranged to allow the passage of a portion of the refrigerant in the form of discharge gas from the compressor to the second latent heat exchanger (that is, without passing through the heat exchange circuit or the expansion valve), a pressure transducer located in the low pressure circuit, configured and arranged to measure the pressure of the refrigerant after passing through the second latent heat exchanger and command the bypass valve so that, in case said pressure drops and reaches a minimum threshold value due to the generation of frost, the compressor provides compressed refrigerant at high pressure and high temperature to the second latent heat exchanger.

[0020] Thanks to this configuration, when the pressure transducer detects that frost could begin to form, the bypass valve allows a portion of refrigerant from the compressor to pass to the second latent heat exchanger (which in heating mode works as an evaporator), thus carrying out defrosting without having to stop or reverse the operating cycle.

[0021] Preferably, the heat pump system comprises a direction valve, for example of the 3-way or 4-way type, configured to receive the refrigerant from the compressor and / or from the second latent heat exchanger and direct it towards a suction accumulator and / or towards the heat exchange assembly.

[0022] In one possible embodiment, the heat pump system comprises a control system configured and arranged to receive pressure transducer measurements and control the opening and closing of the bypass valve. Optionally, the control system is also configured and arranged to regulate the compressor's operating power so that it can provide a greater amount of refrigerant if required by the heat pump system.

[0023] Brief description of the figures

[0024] Figure 1.- It is a schematic representation of an embodiment of the present heat pump system. Description of a preferred embodiment

[0025] In view of the aforementioned figure and in accordance with the adopted numbering, an exemplary embodiment of the present heat pump system is described below. As can be seen in figure 1 , this preferred embodiment comprises: a compressor (5), a first fan (22), a heat exchange assembly defined by:

[0026] • a first latent heat exchanger (1),

[0027] • a first sensible heat exchanger (3),

[0028] • a second sensible heat exchanger (4), a main valve (7), a secondary main valve (8), a second secondary valve (9), a first check valve (11), a second check valve (12), an expansion valve (6), a second fan (21), a second latent heat exchanger (2), a solenoid type bypass valve (10), a pressure transducer (15), a suction accumulator (13), a direction valve (14), a first temperature sensor (23) located at the inlet of the first enclosure (41), a second temperature sensor (24) located at the outlet of the first enclosure (41), an air filter (25) located at the inlet of the first enclosure (41).

[0029] As can be seen in Figure 1, both the first fan (22) and the heat exchange assembly are housed in a first enclosure (41), such that the first fan (22) generates a first air flow (31a - 31 d) that passes through the first enclosure (41) from its inlet to its outlet, passing through the first sensible heat exchanger (3), the first latent heat exchanger (1) and the second sensible heat exchanger (4), in that order.

[0030] The main valve (7) controls the passage of refrigerant from the compressor (5) to the first latent heat exchanger (1), while the secondary valves (8, 9) control the passage of refrigerant from the compressor (5) to the two sensible heat exchangers (3, 4).

[0031] The heat pump system also comprises a control system that controls the opening and closing of said main (7) and secondary (8, 9) valves, as well as the regulation of the compressor (5) and the direction valve (14), so that the heat pump system can work both in heating mode and in cooling mode.

[0032] When the heat pump system works in heating mode, the compressor (5) compresses the refrigerant, which receives it in a gas state, and increases its pressure and temperature.

[0033] In a first conventional heating operating mode, the control system opens the main valve (7) while closing the first secondary valve (8) and the second secondary valve (9). In this way, the refrigerant coming from the compressor (5) only goes towards the first latent heat exchanger (1), which works as a condenser. After this, the refrigerant is directed, now in a liquid state, towards the expansion valve (6), where its pressure is reduced, obtaining a percentage of the refrigerant in a gaseous state and another in a liquid state, and towards the second latent heat exchanger (2), which in this mode works as an evaporator.From the latter, the refrigerant returns in a gaseous state to the compressor (5) passing through the suction accumulator (13), which is configured and arranged to retain the refrigerant in a liquid state that comes out of the second latent heat exchanger (2) and provide only the refrigerant in a gaseous state to the compressor (5).

[0034] In a second heating operating mode, the heat pump system is intended to operate without stopping when the first incoming air flow (31a) reaching the first enclosure (41) is at a temperature below the minimum condensation temperature allowed by the compressor (which would prevent a conventional heat pump from operating correctly). For example, when the equipment is outdoors at temperatures below 10°C. In this mode, the control system closes the main valve (7) and, optionally, the second secondary valve (9), while opening the first secondary valve (8). In this way, the refrigerant coming from the compressor (5) in a gas state and at a temperature corresponding to the compressor discharge temperature is directed towards the first sensible heat exchanger (3).This is designed not to exceed the amount of heat exchange between the refrigerant and the air from which the refrigerant would begin to condense. In other words, the size, geometry and / or physical parameters of the first sensible heat exchanger (3) are suitable so that the refrigerant only transfers the heat energy corresponding to its sensible heat in the high pressure circuit to the first incoming air flow (31a) that passes through it (specifically up to a minimum temperature necessary for the refrigerant to condense and evaporate within the working area of ​​the compressor and for it not to stop).Subsequently, the refrigerant still in gas state, through the first check valve (11), is directed towards the first latent heat exchanger (1), which acts as a condenser, in such a way that latent heat of the refrigerant is transmitted (that is, there is a change of state from gas to liquid by this) to the preheated air flow (31 b) that passes through it coming from the first sensible heat exchanger (3). Thanks to this, the heat pump system manages to increase the temperature of the preheated air flow (31 b) to the value necessary to work properly. It should be noted that the second sensible heat exchanger does not have to work in this operating mode (it could even not be there, nor could the valves that allow the refrigerant to be sent to said exchanger), although, as described later, it would also be possible by increasing the amount of refrigerant supplied by the compressor (5).

[0035] In a third heating operating mode, the heat pump system is intended to obtain an outgoing air temperature (31 d) at least 20°C above the condensation temperature of the refrigerant (for example, in the case of refrigerant R410A, the temperature of said air would be at least 80°C). In this mode, the control system closes the main valve (7) (optionally also the first secondary valve (8)), while opening the second secondary valve (9). In this way, the refrigerant coming from the compressor (5) is directed towards the second sensible heat exchanger (4), which, in turn, receives the hot air flow (31 c) that has just left the first latent heat exchanger (1). The second sensible heat exchanger (4) is designed not to exceed the amount of heat exchange between the refrigerant and the hot air flow (31 c) from which the refrigerant would begin to condense.In other words, the size, geometry and / or physical parameters of the second sensible heat exchanger (4) are suitable for the refrigerant to only transfer the heat energy corresponding to its sensible heat in the high pressure circuit to the hot air flow (31c) passing through it. Subsequently, the refrigerant, still in a gaseous state, is directed through the second check valve (12) towards the first latent heat exchanger (1), which acts as a condenser and heats the first incoming air flow (31a) to a maximum of the temperature corresponding to the condensation temperature. Thanks to this configuration, the heat pump system manages to increase the temperature of the hot air flow (31c) to values ​​of between 20°C or more above the condensation temperature.It should be noted that the first sensible heat exchanger (3) does not have to work in this operating mode (it is not even mandatory that it be there, nor are the valves that give access to the refrigerant to said exchanger, although it would also be possible by increasing the amount of refrigerant supplied by the compressor (5).

[0036] The second fan (21) and the second latent heat exchanger (2) are housed in a second enclosure (42). The second fan (21) is configured and arranged to generate a second air flow (32a - 32b) that passes through the second enclosure (42) from its inlet to its outlet through the second latent heat exchanger (2). As has been discussed, the latter is configured and arranged to act as an evaporator when the heat pump system operates in a heating mode, that is, to receive the refrigerant in a liquid state coming from the expansion valve (6) and produce a transfer of mainly latent heat from the second air flow (32a - 32b) to the refrigerant, producing the evaporation of the refrigerant.

[0037] In this exemplary embodiment, the system also comprises a bypass valve (10) arranged to allow a percentage of the refrigerant to pass in the form of discharge gas from the compressor (5) to the second latent heat exchanger (2), i.e. without passing through the heat exchange circuit or the expansion valve (6). When the pressure transducer (15) measures that the pressure of the refrigerant after passing through the second latent heat exchanger (2) is too low, causing frost to form, the control system opens the bypass valve (10) and compressed high pressure, high temperature refrigerant is provided to the second latent heat exchanger (2), thereby increasing the pressure and temperature, eliminating the frost in the second latent heat exchanger (2) without requiring a cycle reversal.

Claims

CLAIMS 1. Heat pump system suitable for working in heating mode and in cooling mode, comprising: an inverter type compressor (5) configured and arranged to, when the pump system works in heating mode, compress a refrigerant received in gas state, increasing its pressure and temperature, a first enclosure (41) provided with a first fan (22) configured and arranged to generate a first air flow (31a - 31d) that passes through the first enclosure (41) from its inlet to its outlet, a heat exchange assembly housed in the first enclosure (41), the heat exchange assembly being configured and arranged to, when the pump system works in heating mode, receive the refrigerant in gas state coming from the compressor (5),the heat exchange assembly being provided with at least a first latent heat exchanger (1) configured and arranged to produce a transfer of mainly latent heat from the refrigerant to the first air flow (31a - 31 d), the first air flow (31a - 31 d) being condensed, an expansion valve (6) configured and arranged to, when the pump system operates in heating mode, reduce the pressure of the refrigerant coming from the first latent heat exchanger (1), a second enclosure (42) provided with a second fan (21) configured and arranged to generate a second air flow (32a - 32b) that passes through the second enclosure (42) from its inlet to its outlet, a second latent heat exchanger (2) housed in the second enclosure (42), the second latent heat exchanger (2) being configured and arranged to, when the pump system operates in a heating mode,receiving the refrigerant in liquid state coming from the expansion valve (6) and producing a transfer of mainly latent heat from the second air flow (32a - 32b) to the refrigerant, producing the evaporation of the refrigerant, characterized in that the heat exchange assembly comprises at least one sensible heat exchanger (3, 4) configured and arranged to receive the refrigerant in gas state coming from the compressor (5) prior to the first latent heat exchanger (1), while receiving the first air flow (31a - 31 d), also before the first latent heat exchanger (1) and increase its temperature only by sensible heat of the refrigerant.

2. Heat pump system according to claim 1, characterized in that the at least one sensible heat exchanger (3) is configured and arranged to receive the first air flow (31a - 31 d) prior to the first latent heat exchanger (1).

3. Heat pump system according to claim 1, characterized in that the at least one sensible heat exchanger (4) is configured and arranged to receive the air flow (31a - 31 d) after the first latent heat exchanger (1).

4. Heat pump system according to any of the preceding claims, characterized in that it comprises: a main valve (7) configured and arranged to control the passage of refrigerant from the compressor (5) directly to the first latent heat exchanger (1), at least one secondary valve (8, 9) configured and arranged to control the passage of refrigerant from the compressor (5) to the at least one sensible heat exchanger (3, 4), a control system configured and arranged to control the opening and closing of the main valve (7) and of the at least one secondary valve (8, 9), at least one check valve (11, 12) configured and arranged so that the refrigerant coming from the at least one sensible heat exchanger (3, 4) or that coming from the main valve (7) is directed towards the first latent heat exchanger (1) and does not flow back towards the at least one sensible heat exchanger (3, 4).

5. Heat pump system according to any of the preceding claims, characterized in that it comprises: a first sensible heat exchanger (3) configured and arranged to receive the first air flow (31a - 31 d) prior to the first latent heat exchanger (1), a second sensible heat exchanger (4) configured and arranged to receive the first air flow (31a - 31 d) after the first latent heat exchanger (1), a first secondary valve (8) and a second secondary valve (9) configured and arranged to control the passage of refrigerant from the compressor (5) to respective sensible heat exchangers (3, 4), a first check valve (11) and a second check valve (12) configured and arranged so that the refrigerant coming from respective sensible heat exchangers (3, 4) is directed towards the first latent heat exchanger (1).

6. Heat pump system according to any of the preceding claims, characterized in that it comprises: a bypass valve (10), configured and arranged to allow the passage of a portion of the refrigerant in the form of discharge gas from the compressor (5) towards the second latent heat exchanger (2), - a pressure transducer (15) configured and arranged to measure the pressure of the refrigerant after passing through the second latent heat exchanger (2) and control the bypass valve (10) so that, in the event that said pressure drops and reaches a minimum threshold value due to the generation of frost, it provides it with compressed refrigerant at high pressure and high temperature.

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