Patent Description:
Typical fields of usage of heat pumps are to cool a region to be cooled and/or to heat a region to be heated. A heat pump typically consisting of an evaporator, a compressor and a condenser comprises, for this purpose, an evaporator side on the one hand and a condenser side on the other hand, as is shown exemplarily by the heat pump <NUM> in <FIG>. The heat pump is coupled to a heat exchanger <NUM> on the evaporator side and a heat exchanger <NUM> on the condenser side. For this purpose, the heat pump <NUM> in particular includes an evaporator inlet 101a and an evaporator outlet 101b. Above that, the heat pump <NUM> comprises a condenser inlet 103a and a condenser outlet 103b. The operating liquid on the evaporator side is introduced into the evaporator of the heat pump <NUM> via the evaporator inlet 101a, cooled there and let out from the evaporator outlet 101b as colder operating liquid. At the same time, as shown in <FIG>, the evaporator inlet 101a and the evaporator outlet 101b are coupled to the heat exchanger <NUM>, such that a hotter operating liquid (having the temperature t) is fed into the heat exchanger, cooled in the heat exchanger and then transported to the region to be cooled. Typical temperature ratios are shown in <FIG>, wherein a "heat exchanger loss" of <NUM> °Celsius is assumed. In particular, e.g., the set temperature is in the region to be cooled.

The heat exchanger <NUM> or <NUM> has a primary side directed towards the heat pump and a secondary side facing away from the heat pump, i.e. to the region to be cooled or the region to be heated. The primary side of the heat exchanger <NUM> includes the hot terminal 101a and the cold terminal 101b, wherein "hot" and "cold" are to be seen as terms, and wherein the medium is hotter in terminal 101a than in terminal 101b. Accordingly, the hot terminal of the primary side of the heat exchanger <NUM> is the terminal 103b, and the cold terminal is the terminal 103a. On the secondary side of the heat exchangers <NUM> or <NUM>, the hot terminal is in each case the top terminal and the cold terminal is in each case the bottom terminal in <FIG>.

On the condenser side of the heat pump <NUM>, the condenser outlet 103b is connected to the "hot" terminal of the heat exchanger <NUM>, and the condenser inlet is connected to the colder end of the heat exchanger <NUM>. Above that, on its other side facing away from the heat pump <NUM>, the heat exchanger is connected to the region to be heated, where a set temperature T should prevail.

If the heat pump is used as a cooling unit, the region to be cooled will, so to speak, be the "effective side". The region to be cooled can, for example, be an indoor room, such as a computer room or another room to be cooled or air-conditioned. Then, the region to be heated would, for example, be the outside wall of a building or a rooftop or another region into which waste heat is to be introduced. If, however, the heat pump <NUM> is used as heating, the region to be heated will, so to speak, be the "effective side" and the region to be cooled would, for example, be soil, ground water or the like.

In such heat pump applications as shown in <FIG>, it is problematic that the configuration does not take into consideration that the ambient temperature of the region to be heated, when the same is, for example, outdoors, varies heavily. In winter, temperatures of -<NUM> °Celsius can prevail, and in summer temperatures of over <NUM> °Celsius. If, for example, an application is considered where a computer room is air-conditioned, it would be sufficient, for the case that the ambient temperature is, e.g., in the range of or below the set temperature in the region to be cooled, to no longer air-condition the computer room at all, but to simply "open the windows". This is, however, problematic, since computer rooms do not necessarily have windows and because, at the same time when such cooling is considered, it is relatively difficult to check that there is a constant temperature in the room, because of the fact that particularly cold zones might possibly form close to the windows, if there are any, while further away from the windows or behind specific racks hot zones form that might not be sufficiently cooled. On the other hand, it is problematic in that, in a heat pump configuration such as is illustrated in <FIG>, the fact that the ambient temperatures can vary heavily and in particular frequently lie within ranges where cooling is normally not necessitated, is not put to effective use. For that reason, a configuration as illustrated in <FIG> is implemented for the worst-case situation, i.e. for example for a very hot summer day, although such a hot summer day is, on average, very rare, at least in Germany, and the main part of the time within one year has temperatures where the necessitated cooling capacity is far below the requested worst-case situation.

<CIT> discloses a heat pump with a free cooling mode. In the free cooling mode, the evaporator inlet is connected to a return from the region to be heated. Further, the condenser inlet is connected to a return from the region to be cooled. By the free cooling mode, a significant efficiency increase is already obtained, in particular for outside temperatures of less than, for example <NUM>.

However, the free cooling mode also does not obtain the maximum energy-saving potential.

It is the object of the present invention to provide a more efficient heat pump concept. This object is solved by a heat pump according to claim <NUM>, a method for pumping heat according to claim <NUM> or a heat pump system according to claim <NUM>.

A heat pump according to one aspect includes an evaporator with an evaporator inlet and an evaporator outlet as well as a condenser with a condenser inlet and a condenser outlet. Above that, according to the invention a switching means is provided for operating the heat pump in a first operating mode or a second operating mode. In the first operating mode, the heat pump is completely bypassed in that the return of the region to be cooled is directly connected to the forward of the region to be heated. Above that, in this bypass mode, the return of the region to be heated is connected to the forward of the region to be cooled. Typically, the evaporator is allocated to the region to be cooled and the condenser to the region to be heated.

In the first operating mode or bypass mode, however, the evaporator is not connected to the region to be cooled and further the condenser is also not connected to the region to be cooled, but both regions are, so to speak "short-circuited". In the second alternative operating mode, however, the heat pump is not bypassed but typically operated in the free cooling mode at still relatively low temperatures or in the normal mode. In the free cooling mode, the switching means is configured to connect a return of the region to be cooled to the condenser inlet and to connect a return of the region to be heated to the evaporator inlet. On the other hand, in the normal mode, the switching means is configured to connect the return of the region to be cooled to the evaporator inlet and to connect the return of the region to be heated to the condenser inlet.

Depending on the embodiment, at the output of the heat pump, i.e. on the condenser side, or at the input of the heat pump, i.e. on the evaporator side, a heat exchanger can be provided for decoupling the inner heat pump cycle from the outer cycle with regard to liquids. In that case, the evaporator inlet represents the inlet of the heat exchanger coupled to the evaporator. Above that, in that case the evaporator outlet represents the outlet of the heat exchanger which is again firmly coupled to the evaporator.

Analogously, on the condenser side, the condenser outlet is a heat exchanger outlet and the condenser inlet is a heat exchanger inlet on the side of the heat exchanger which is not firmly coupled to the actual condenser.

Alternatively, however, the heat pump can be operated without a heat exchanger on the input side or on the output side. Then, e.g. at the input into the region to be cooled or at the input into the region to be heated, a heat exchanger could respectively be provided, which then includes the return or forward to the region to be cooled or to the region to be heated.

In preferred embodiments of the present invention, the heat pump is used for cooling, such that the region to be cooled is, for example, a room of a building, a computer room or generally a refrigeration room, while the region to be heated is, for example, a roof of a building or a similar position where a heat dissipation device can be placed in order to dissipate heat to the environment.

If, however, as an alternative, the heat pump is used for heating, the region to be cooled is the environment from which energy is to be drawn and the region to be heated, is the "effective application", i.e. for example the inside of a building, a house or a room to be heated.

Thus, the heat pump according to the first aspect is able to switch from the bypass mode either into the free cooling mode, or if such a free cooling mode is not implemented, into the normal mode.

Generally, the heat pump according to the first aspect is advantageous in that the same becomes particularly efficient when outside temperatures prevail that are, for example, less than <NUM>, which is frequently the case, at least in areas of the northern and southern hemisphere distant from the equator.

Thereby, it is obtained that the heat pump can be completely switched off at outside temperatures where direct cooling is possible. In the case of a heat pump with a radial compressor as temperature raiser between the evaporator and the condenser, the radial impeller can be stopped and no more energy has to be supplied to the heat pump. Alternatively, the heat pump can still run in a stand-by mode or the like which, however, causes only little current consumption since the same is only a stand-by mode. In particular in heat pumps without valves, as they are preferably used, a heat short-circuit can be prevented by completely bypassing the heat pump, in contrary to the free-cooling mode.

Above that, it is preferred that in the first operating mode, which according to the invention is in the bypass mode, the switching means separates the return of the region to be cooled or the forward of the region to be cooled completely from the evaporator, such that no liquid connection between inlet and outlet, respectively, of the evaporator and the region to be cooled exists. This complete separation will also be advantageous on the condenser side.

In implementations, a temperature sensor means is provided that detects a first temperature with regard to the evaporator or a second temperature with regard to the condenser. Further, the heat pump has a control that is coupled to the temperature sensor means and is configured to control, in dependence on one or several temperatures detected in the heat pump, the switching means, such that the switching means switches from the first to the second operating mode or vice versa. The implementation of the switching means can be implemented by an input switch and an output switch, each comprising four inputs and four outputs and being switchable depending on the mode. Alternatively, the switching means can also be implemented by several individual cascaded switches, each having an input and two outputs.

Further, as coupling element for coupling the bypass line to the forward into the region to be heated or the coupler for coupling the bypass line to the forward into the region to be cooled, can be configured as a simple three-terminal combination, i.e. as liquid adder. However, in order to have optimum decoupling, it is preferred in implementations to configure the couplers also as switches or integrated in the input switch and output switch, respectively.

According to the invention, as specific temperature sensor, a first temperature sensor is used on the evaporator side and a second temperature sensor is used on the condenser side as second temperature sensor, wherein an even more direct measurement is preferred. The evaporator side measurement is particularly used for performing speed control of the temperature raiser, i.e. a compressor, while the measurement on the condenser side or also a measurement of the environmental temperature, is used for performing mode control, i.e. to switch the heat pump, e.g., from the bypass mode to the free cooling mode when a temperature is no longer in the very cold temperature range but in the medium-cold temperature range. If the temperature is higher, i.e. in a hot temperature range, the switching means will bring the heat pump in a normal mode.

In a two-stage heat pump, in this normal mode, merely a first stage will be active, while the second stage is still inactive, i.e. is not supplied with current and hence necessitates no energy. Only when the temperature rises further, into a very hot range, a second pressure stage will be activated in addition to the first heat pump stage or in addition to the first pressure stage, which again comprises a condenser, a temperature raiser, typically in the form of a radial compressor and a condenser. The second pressure stage can be connected in series or in parallel or in series/parallel to the first pressure stage.

In order to ensure that in the bypass mode, i.e., when the outside temperature is already relatively cold, the cold from the outside does not completely enter the heat pump system and above that into the room to be cooled, i.e. makes the room to be cooled even cooler than it should be, it is preferred to provide, based on a sensor signal at the forward into the region to be cooled or at the return of the region to be cooled, a control signal that can be used by a heat dissipation device mounted outside the heat pump for controlling heat dissipation, i.e. to reduce the same when the temperatures become too cold. The heat dissipation device is, for example a liquid/air heat exchanger having a pump for circulating the liquid introduced into the region to be heated. Further, the heat dissipation device can comprise a fan for transporting air into the air heat exchanger. Additionally or alternatively, a three-way mixer can be provided for partly or completely short-circuiting the air heat exchanger. Depending on the forward into the region to be cooled which, however, in this bypass mode, is not connected to the condenser outlet, but to the return from the region to be heated, the heat dissipation device, i.e., for example the pump, the fan or the three-way mixer is controlled for reducing the heat dissipation further and further so that a temperature level, which may in this case be above the outside temperature level, is maintained both in the heat pump system and in the region to be cooled. Thereby, the waste heat can even be used for heating the room "to be cooled" when the outside temperatures are too cold.

In a further aspect, the entire control of the heat pump is performed such that depending on a temperature sensor output signal of a temperature sensor on the evaporator side, "fine control" of the heat pump is performed, i.e. speed control in the different modes, i.e. for example the free cooling mode, the normal mode with a first stage and the normal mode with a second stage and also control of the heat dissipation device in the bypass mode, while mode switching is performed based on a temperature sensor output signal of a temperature sensor on the condenser side. Thereby, merely based on a condenser side temperature sensor, operating mode switching from the bypass mode into the free cooling mode and/or into the normal mode is performed, wherein for a decision whether switching takes place, the temperature output signal on the evaporator side is not used. However, for speed control of the radial compressor or for controlling the heat dissipation devices, again, merely the temperature output signal on the evaporator side is used, but not the sensor output signal on the condenser side.

It should be noted that the different aspects of the present invention, on the one hand the usage of the bypass mode, on the other hand the control of the heat dissipation device in the bypass mode or free cooling mode and the control of the radial compressor in the free cooling mode or the normal operating mode on the other hand, or also the third aspect of using two sensors, wherein one sensor is used for operating mode switching and the other sensor for fine control, can be used independently of one another. However, these aspects can also be combined in pairs or together.

Advantages of the first aspect are that, when the outside temperatures are cold enough, the heat pump can be completely bypassed and hence has to consume no energy. For obtaining security that the entire system and in particular the region to be cooled do not become too cold, the heat dissipation device is controlled in order to obtain, in a way, "isolation" from the outside world that is too cold.

The second aspect is advantageous in that exactly that insulation from the outside world is obtained independent of whether the heat pump runs in the bypass mode or in the free cooling mode when, for example, only the free cooling mode and the normal mode are implemented but not the bypass mode. Then, typically at low speed of the heat pump which should not be completely switched off for preventing short-circuit within the heat pump, undercooling of the system and region to be cooled can still be prevented.

The third aspect is advantageous in that transparent and efficient control is obtained, obtaining, on the one hand, "coarse control" due to the mode switching and, on the other hand, "fine control" due to the temperature-dependent speed control in that only that much energy is consumed as is actually needed at the time. This procedure where the heat pump is not constantly switched on and switched off, for example in known heat pumps with hysteresis, also ensures that due to the continuous operation no start-up losses occur.

Preferred embodiments of the present invention will be discussed in more detail below with reference to the accompanying drawings. They show:.

<FIG> shows a heat pump according to the present invention having an evaporator <NUM> comprising an evaporator inlet 10a and an evaporator outlet 10b. Further, the heat pump includes a condenser <NUM> with a condenser inlet 12a and a condenser outlet 12b. Apart from the switching means that can be implemented by elements <NUM>, <NUM>, <NUM>, <NUM>, the evaporator inlet 10a is connected to a return 15b from a region to be cooled <NUM>. Above that, apart from the coupler <NUM>, the evaporator outlet 10b is connected to a forward 15a into the region to be cooled <NUM>.

On the condenser side, the condenser outlet 12b is connected to a forward 17a, again apart from the coupler <NUM>, to a region to be heated <NUM>. Above that, the region to be heated <NUM>, and in particular its return 17b is, again apart from the switch <NUM>, connected to the condenser inlet 12a. Thus, the heat pump includes a switching means preferably implemented by elements <NUM>, <NUM>, <NUM>, <NUM> and that is configured to connect, in the first operating mode, a return, namely the return 15b of the region to be cooled <NUM>, to the forward 17a of the region to be heated <NUM> via a first bypass line <NUM> and to connect a return 17b of the region to be heated <NUM> to the forward 15a of the region to be cooled <NUM> via a further bypass line <NUM>. Further, the heat pump means is configured to connect, in a second operating mode, the return 15b of the region to be cooled <NUM> to the evaporator inlet 10a (in the normal mode) or the condenser inlet 12a (in the free cooling mode), and to connect the return 17b of the region to be heated <NUM> to the condenser inlet 12a (in normal operation or normal mode) or the evaporator inlet 10a (in the free cooling mode).

In embodiments, the switching means is configured to separate, in the first operating mode, the return 15b of the region to be cooled <NUM> or the forward 15a of the region to be cooled from the condenser <NUM> or its inlet 10a and outlet 10b, respectively, such that no liquid connection exists between the forward 15a and the return 15b of the region to be cooled and the evaporator <NUM>. On the condenser side, the switching means is also preferably configured to completely separate, in the bypass mode, the condenser outlet 12b from the forward 17a into the region to be heated and to further also completely separate, in the bypass mode, the return 17b from the region to be heated <NUM>, i.e. the line 17b from the condenser inlet 12a. This complete separation is obtained, for example by the switches <NUM>, <NUM> in <FIG> that are controlled via a control line 26a and 24a, respectively. The coupler <NUM> on the condenser side and the coupler <NUM> on the evaporator side, respectively, do not have to be configured for complete separation but can also be merely a line coupling, i.e. a line coupling having two inputs and one output. However, as mentioned, complete separation is preferred, such that the couplers <NUM>, <NUM> are also controlled by a control <NUM> for the switching means.

In specific embodiments, the heat pump includes, apart from the evaporator <NUM> and the condenser <NUM>, a temperature raiser <NUM> for raising the temperature in the evaporated operating liquid. The temperature raiser <NUM> is preferably configured as radial compressor with a radial impeller, but can also be configured as any other temperature raiser such as any other compressor. Above that, the heat pump includes a feedback means R <NUM> when the heat pump is configured as closed heat pump. If, however, the heat pump is configured as open heat pump, the feedback means R is not absolutely necessitated.

Above that, it should be noted that no further heat exchangers are illustrated in <FIG>, as they can be used, for example, at the evaporator input 10a, at the condenser output 12b, at the input 15a into the region to be cooled <NUM> or at the input 17a into the region to be heated <NUM>, wherein heat exchangers are illustrated, for example in Fig. <NUM> at <NUM> (heat exchanger on the evaporator side allocated to the region to be cooled <NUM>) or <NUM> (heat exchanger on the condenser side allocated to the region to be heated <NUM>).

The control <NUM> for the switching means <NUM>, <NUM>, <NUM>, <NUM> further comprises a power control unit 29a for providing, on the one hand, a control signal 36a for the temperature raiser and, on the other hand, for providing a control signal 36b for a heat dissipation device. The control signal 36b is preferably provided only in the first operating mode, i.e. in the bypass mode in order to control a heat dissipation device in the region to be heated which is not illustrated in <FIG>.

<FIG> shows a heat pump system with a heat pump and the region to be heated <NUM> and the region to be cooled <NUM> and in particular with forward lines to the regions and return lines from the regions.

The heat pump includes the evaporator <NUM> with the evaporator inlet 10a and the evaporator outlet 10b. Further, the heat pump includes the condenser <NUM> with the condenser inlet 12a and the condenser outlet 12b. Further, the heat pump typically includes a compressor illustrated at <NUM> in <FIG> for compressing operating liquid evaporated in the evaporator <NUM>, wherein the condenser <NUM> is implemented to compress the evaporated operating liquid compressed in the compressor. The compressor is preferably implemented as turbo compressor having a typically fast rotating radial impeller to handle the necessitated compressor capacity. An exemplary heat pump is described in <CIT>.

Above that, the heat pump configuration in <FIG> includes forward and return lines, wherein in particular the forward line to the region to be cooled <NUM> is indicated by 15a, and wherein the return line from the region to be cooled <NUM> is indicated by 15b. Further, the region to be heated <NUM> is allocated to the heat pump, which again comprises the forward line 17a and the return line 17b. Above that, in one embodiment of the invention, the heat exchanger <NUM> is allocated to the region to be cooled <NUM>, and the heat exchanger <NUM> is allocated to the region to be heated. Both heat exchangers <NUM>, <NUM> each have again a primary side directed towards the heat pump, and a secondary side facing away from the heat pump, i.e. to the region to be cooled in the case of the heat exchanger <NUM> and the region to be heated in the case of the heat exchanger <NUM>. The primary side of the heat exchanger <NUM> includes the hot terminal 15b representing the return from the region to be heater, and includes the cold terminal 15a representing the forward 15a to the region to be cooled. On the secondary side, the heat exchanger further includes a hot terminal 15c and a cold terminal 15d.

Accordingly, the heat exchanger <NUM> allocated to the region to be heated again includes a hot terminal 17a representing the forward 17a of the region to be heated, and a cold terminal 17b representing the return 17b of the region to be heated <NUM>. On the secondary side, the heat exchanger <NUM> again includes a hot terminal 17c and a cold terminal 17d. It should be noted that the heat exchangers are not absolutely necessitated. Instead, the operating liquid can also be guided directly into the region to be heated or into the region to be cooled, wherein, however, there will always be a forward and a return into or from the region to be heated or to be cooled. It should be noted that the terms "hot" and "cold" should be seen as designations, wherein, however, it should be noted that the liquid in the hot terminal is hotter than the cold terminal. Thus, the hot terminal of the primary side of the heat exchanger <NUM> is the terminal 15b and the cold terminal is the terminal 15a.

<FIG> further shows a first connecting line 14a arranged between the evaporator <NUM> and the coupler <NUM>. A second connecting line 14b is arranged between an evaporator switch comprising switches I and II and a condenser switch comprising switches III and IV. The second connecting line 14b is connected to a first input <NUM> of the first switch I and a first input <NUM> of the third switch III.

<FIG> further shows a third connecting line 16a arranged between the condenser <NUM> and the coupler <NUM>. A fourth connecting line 16b is arranged between a condenser switch comprising switches III and IV and an evaporator switch comprising switches I and II. The fourth connecting line 16b is connected to a second input <NUM> of the fourth switch IV and a second input <NUM> of the second switch II.

<FIG> further shows various temperature specifications at the respective terminals. Thus, in the embodiment shown in <FIG>, it is assumed that the temperatures of the heat exchanger <NUM> or its secondary side, i.e. for example <NUM> °Celsius and <NUM> °Celsius, are obtained when the air has a temperature of, e.g. <NUM> °Celsius. Here, the secondary circuit with terminals 17c, 17d of the heat exchanger <NUM> could be connected to a fan blowing the ambient air having, for example, <NUM> °Celsius, through a radiator, whereby the liquid is cooled from <NUM> °Celsius to <NUM> °Celsius. On the primary side of the heat exchanger <NUM>, this means that the forward has a temperature of <NUM> °Celsius and the return a temperature of <NUM> °Celsius. Since the temperature of <NUM> °Celsius is already within the order in which the evaporator is normally "fed", according to the invention, the return of the heat exchanger <NUM> or the return from the region to be heated is fed into the evaporator inlet. The evaporator obtains cooling down by <NUM> °Celsius at the evaporator outlet and thus obtains a temperature of <NUM> °Celsius, which is suitable for reaching a respective set temperature in the region to be cooled which is, for example, <NUM> °Celsius. This temperature can be found at the hot terminal of the secondary side of the heat exchanger <NUM> allocated to the region to be cooled, and reflects the situation where the object to be cooled has output so much energy to the medium that the cooling agent has warmed up from <NUM> °Celsius to <NUM> °Celsius. Due to the heat exchanger, this means that the hot terminal of the heat exchanger of the region to be cooled has a temperature of <NUM> °Celsius. Contrary to the standard configuration where the return is coupled to the evaporator, the return is now coupled to the condenser inlet 12a, and the water which is preferably used as cooling agent is heated to <NUM> °Celsius in the condenser due to the heat pump operation, and this energy is then dissipated via the region to be heated or the heat exchanger <NUM>. It is decisive that the temperature difference prevailing between the evaporator outlet 10b and the condenser outlet 12b is now merely <NUM> °Celsius. This is a low temperature difference compared to the normal operation which is indicated in <FIG> and which amounts to, for example, <NUM> °Celsius. According to the invention, the lower ambient temperature is used by the specific wiring such that a low temperature difference is obtained for the heat pump. Since the temperature difference, contrary to the passage, enters the power consumption of the heat pump in a square manner (the passage enters only in a linear manner), any reduction of the temperature difference to be provided by the heat pump results in significant power savings and hence in an efficiency increase.

In a preferred embodiment of the present invention, the configuration of the heat pump is implemented in a switchable manner. For this, a switching means is provided that is configured to separate the evaporator inlet 10a from the return 17b from the region to be heated <NUM> and from the fourth connecting line 16b, and to couple the return 15b from the region to be cooled to the evaporator inlet 10a. In the embodiment shown in <FIG>, this functionality is obtained by the two switches I and II representing an evaporator switch. Further, the switching means is configured to separate the condenser inlet 12a from the return 15b from the region to be cooled <NUM> and from the second connecting line 14b, and to couple the return 17b from the region to be heated <NUM> to the condenser inlet 12a. This functionality is obtained in the embodiment shown in <FIG> by the two switches III and IV representing the evaporator switch.

The switch positions of switches I, II, III, IV are illustrated for the two variations, i.e. the free cooling mode as shown in <FIG> and the normal operating mode as shown in <FIG>. In normal mode, switch I is at position <NUM>, switch II is at position <NUM>, switch III is at position <NUM> and switch IV is at position <NUM>. In contrast, in the free cooling mode, switch I is at position <NUM>, in the free cooling mode, switch II is at position <NUM>, in the free cooling mode, switch III is at position <NUM>, and in the free cooling mode, switch IV is at position <NUM>. With respect to the circulation of liquids, the free cooling mode is as illustrated in <FIG>, and with respect to the circulation, the normal operating mode is as illustrated in <FIG>. This means in the embodiment shown in <FIG>, based on assumed realistic ambient temperatures in the summer of <NUM> °Celsius, that the liquid in the cold terminal 17d of the secondary side of the heat exchanger for the region to be heated has a temperature of <NUM> °Celsius and is heated up to <NUM> °Celsius due to the heat exchanger effect. On the primary side of the heat exchanger <NUM>, this means that the forward has a temperature of <NUM> °Celsius and the return a temperature of <NUM> °Celsius. However, on the evaporator side, as in the embodiment shown in <FIG>, the secondary side of the heat exchanger <NUM> has the same set temperatures as in <FIG>, and the primary side also has the same set temperatures. However, this means that the heat pump with the evaporator <NUM> and the condenser <NUM> has to overcome a significant temperature difference in the normal operating mode, i.e. <NUM> °Celsius when the ambient temperature has an assumed maximum of, e.g., <NUM> °Celsius.

In preferred embodiments of the present invention, as shown in <FIG> by the control <NUM>, reconfiguration is performed depending on the temperature in the region to be heated, i.e. e.g. on the ambient temperature on a roof or on a facade of a building. If, in preferred embodiments of the present invention, the ambient temperature is less than or equal to <NUM> °Celsius, and in particular less than or equal to <NUM> °Celsius, the control can control switches I, II, III, IV such that the free cooling mode of <FIG> becomes active, while the normal mode will be controlled when the temperatures are above that. Thus, depending on the implementation, the normal mode can already be activated starting from <NUM> °Celsius ambient temperature, and, depending on the implementation, also, for example, already starting from <NUM> °Celsius ambient temperature. The exact switching temperature depends in particular also on the implementation of the system and also on the implementation of the heat exchangers or whether heat exchangers are used at all. Further, it is also significant how strongly the heat transfer takes place from the ambient temperature into the secondary side of the heat exchanger <NUM> or, when no heat exchanger is used, into the forward and return 17a, 17b.

Switching can also take place in a manual or time-controlled manner or by a combination of the stated measures. Manually operated switching can be performed by an operator of the plant, who receives the suggestion to reconfigure, for example by any type of display. Alternatively, switching can also take place in a time-controlled manner, for example such that the plant is operated in the free cooling mode in winter, in the normal operating mode in summer, in the normal operating mode during the day in spring and autumn, and in the free cooling mode at night. Alternatively, the temporal condition and the temperature condition can be combined to control automatically or to give the operator an optimum suggestion for the configuration of the heat pump system.

In the following, the individual switches in <FIG> will be discussed in more detail. The switch I includes an input connected to the hot terminal of the primary side of the first heat exchanger <NUM>. Further, the switch includes two outputs, wherein the first output is connected to a first input of the switch III via the second connecting line 14b, and wherein the second output is connected to a first input of the switch II. The switch I can be controlled by the control <NUM> such that the input is either connected to the first output or to the second output.

The switch II includes a single output connected to the evaporator inlet 10a. Above that, switch II includes two inputs, wherein the first input is connected to the second output of the switch I, and wherein the second input is connected to the second output of the switch IV via the fourth connecting line 16b. Again, the control <NUM> can control, for example electrically or mechanically or in any other way, the switch II such that the output is either connected to the first input or to the second input.

The switch III again comprises two inputs and one output. The output of the switch III is connected to the condenser inlet 12a. The first input is connected to the first output of the switch I via the second connecting line 14b, and the second input is connected to a first output of the switch IV. Again, the control <NUM> is implemented to activate the switch III, for example electrically or in any other way, such that either the first input or the second input is connected to the output of the switch and hence to the condenser inlet 12a.

The switch IV includes a single input connected to the cold terminal 17b of the heat exchanger <NUM> and in particular its primary side, while a first output of the switch IV is connected to a second input of the switch III, while the second output of the switch IV is connected to the second input of the switch II via the fourth connecting line 16b. Again, the control <NUM> is implemented to activate the switch IV, for example electrically or in any other way, such that the input is either connected to the first output or to the second output. In particular, it is preferred to form or couple the connections in a pressure-tight and liquid-tight manner, wherein respective liquid switches are known in the art and typically have three pipe terminals towards the outside, by which the switches can be coupled to the other respective terminals via pipes, preferably plastic pipes, in a pressure-and liquid-tight manner.

The first connecting line 14a connects the evaporator outlet 10b to a first input of the coupler <NUM> on the evaporator side and the third connecting line <NUM> connects the condenser outlet 12b to an input of the coupler <NUM> on the evaporator side.

While so far, with reference to <FIG>, switching between the free cooling mode and normal mode has been described, switching from normal mode or free cooling mode to the bypass mode will now be described. After switches <NUM> and <NUM> have so far not been in the bypass mode, i.e. the bypass lines <NUM> and <NUM> have been deactivated, the same are now active. Thereby, the return 15b of the region to be cooled <NUM> is now directly connected to the forward 17a of the region to be heated <NUM>. Accordingly, the bypass line <NUM> is also active, such that the return of the region to be heated <NUM>, i.e. 17b is connected to the forward 15a into the region to be cooled <NUM> via the bypass line <NUM>.

Above that, several temperature sensors <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are shown. Depending on the implementation, switching between the free cooling mode and the bypass mode, in particular switching into the bypass mode is performed by the control <NUM> when the temperature of the sensor <NUM>, i.e. T14b is greater than the temperature of the sensor <NUM>, i.e. T12b.

A respective control can also be performed based on the two sensors <NUM> and <NUM> in that the temperature output signals of the sensor <NUM>, i.e. S16b and the sensor <NUM>, i.e. S14a are fed into the control <NUM>, are compared there and that then switching into the bypass mode is performed when the temperature of the sensor <NUM> is lower than or equal to the temperature of the sensor <NUM>.

Switching into the bypass mode preferably takes place when either the one condition or the other condition or both conditions are fulfilled. The output signals of the two controls <NUM> shown in <FIG> can, for example, be connected by an OR connection in order to determine by the control <NUM> whether switching into the bypass mode or short-circuit mode between a region to be heated and a region to be cooled has to take place or not.

<FIG> shows an implementation of a heat pump stage, in particular the structure of a heat pump unit of which one or several can exist in a heat pump stage. A heat pump unit consists of an evaporator <NUM>, a compressor <NUM> and a condenser <NUM>. The evaporator <NUM> includes an evaporator inlet for introducing the ("hot") operating medium to be evaporated, and further includes an evaporator outlet for letting out the ("cold") evaporating medium.

Accordingly, the condenser <NUM> includes a condenser inlet for introducing the "cold" operating medium and for letting out the "hot" operating medium, wherein the media in the evaporators <NUM> and <NUM> are liquids. Above that, by the heat pump process, "cold" vapor from the evaporator <NUM> is compressed by the compressor <NUM> and heated, and the "hot" vapor is then fed into the condenser <NUM>, so that the "hot" vapor condenses and the liquid in the condenser <NUM> which is then let out through the condenser outlet, is heated by the "hot" vapor due to the condensation process. When a heat pump stage merely comprises one heat pump unit shown in <FIG>, the inlets and outlets illustrated in <FIG> and <FIG> correspond to the inlets and outlets of <FIG>. Thus, each heat pump stage can also comprise an interconnection of individual heat pump units, such as the two heat pump units <NUM>, <NUM> in <FIG>. With respect to the designation of the inflows for the evaporator and the condenser or the outflows for the evaporator and the condenser, it has been assumed that the heat pump in <FIG> consists of a parallel connection of two heat pump units <NUM>, <NUM> of <FIG>.

<FIG> shows the temperature raiser <NUM> controlled by the control <NUM> via the control line 36a. The heat pump in particular is configured to supply the temperature raiser <NUM> with a second power in the second operating mode, i.e. the free cooling mode or the normal mode, and to supply, in the first operating mode, i.e. the bypass mode, the temperature raiser <NUM> with no power or with an "idle" power which is at least less than <NUM> % of the second power. Thereby, it is ensured that optimum efficiency and energy savings, respectively, is obtained. In particular, the evaporator <NUM>, the condenser <NUM> and the temperature raiser <NUM> are configured without valves for obtaining a simple and again efficient structure. Even when the heat pump operates in the idle mode or is completely deactivated, the occurring temperature short-circuit does not result in a failure since in the first operating mode, where such a temperature short-circuit is obtained, the heat pump is bypassed anyway by the bypass lines <NUM>, <NUM> and the switches <NUM>, <NUM>.

<FIG> shows an overview of different modes in which the heat pump according to <FIG>, <FIG>, <FIG>, <FIG> can be operated. If the temperature of the region to be heated is very cold, such as less than <NUM>, the operating mode selection will activate the first operating mode where the heat pump is bypassed and the control signal 36b for the heat dissipation device is generated in the region to be heated <NUM>. If the temperature of the region to be heated, i.e., the region <NUM> of <FIG> is, in a medium-cold temperature range, for example in a range between <NUM> and <NUM>, the operating mode control will activate the free cooling mode in which, due to the lower temperature spread, the first stage of the heat pump can operate in a low power mode. If, however, the temperature of the region to be heated is in a hot temperature range, i.e. for example between <NUM> and <NUM>, the heat pump will operate in a normal mode, but in the normal mode with a first heat pump stage. If, however, the outside temperature is very hot, i.e. in a temperature range between <NUM> and <NUM>, the second heat pump stage is activated, which also operates in the normal mode and supports the already running first stage.

Preferably, speed control and "fine control", respectively, of a radial compressor is performed within the temperature raiser <NUM> of <FIG> in the temperature range "medium-cold", "hot", "very hot" in order to operate the heat pump always only with the heat/cold power currently required by the actual conditions.

Mode switching is preferably controlled by a temperature sensor on the condenser side, while fine control or the control signal for the first operating mode depends on a temperature on the evaporator side.

<FIG> shows a heat pump system similar to the system of <FIG>, again with the region to be cooled <NUM>, a heat pump <NUM> with mode switching, e.g. a bypass mode, a free cooling mode or a normal mode and a temperature sensor.

Further, the region to be heated <NUM> is provided, which is coupled to the heat pump <NUM>.

Similar to the heat pump <NUM> in <FIG>, the heat pump includes the evaporator with the evaporator inlet 10a and the evaporator outlet 10b. Further, a condenser <NUM> with the condenser inlet 12a and the condenser outlet 12b is provided. Above that, the heat pump includes the temperature raiser <NUM> for raising a temperature of an operating liquid evaporated by the condenser.

Above that, the switching means implemented by elements <NUM>, <NUM>, <NUM>, <NUM> of <FIG> or for example implemented by the input switch <NUM> and the output switch <NUM> of <FIG> is provided. The switching means is configured to switch the heat pump between the first operating mode and the different second operating mode, wherein the first operating mode includes a free cooling mode or a bypass mode and wherein the second operating mode includes the free cooling mode or the normal mode. If the first operating mode is the bypass mode, the second operating mode is the free cooling mode or the normal mode. If the first operating mode, however, is already the free cooling mode, the second operating mode is the normal mode.

Further, the heat pump <NUM> includes temperature sensor means which can include, for example, one or several of the sensors <NUM>, <NUM>, <NUM>, <NUM>, <NUM> as shown in <FIG>. The temperature sensor means is configured to detect a temperature at the evaporator (for example sensors <NUM>, <NUM>) or to detect a temperature at the condenser corresponding, for example to the temperature sensors <NUM>, <NUM>, <NUM>. Above that, a control is provided, for example the control <NUM> of <FIG> for providing a control signal based on the detected temperature. Particularly, the control is configured to provide, in the second operating mode, i.e. when the heat pump is operated in the second operating mode, the control signal to the temperature raiser <NUM>, as shown at 36a, or which is referred to in <FIG> in block <NUM> as "internal control signal". If, however, the heat pump is operated in the first operating mode, the control signal that is provided to the control signal output 36b shown in <FIG> and also in <FIG> based on the temperature. The control signal output 36b can be connected to a control input of a heat dissipation device when the heat pump is operated in the first operating mode. Such a heat dissipation device is shown, for example at <NUM> in <FIG>.

In the embodiment shown in <FIG>, the heat dissipation device <NUM> includes an input heat exchanger <NUM>, an air/liquid/heat exchanger <NUM>, a pump <NUM> and a <NUM>-way mixer and a <NUM>-way valve <NUM>, respectively. On the input side, the heat exchanger <NUM> is connected to the heat pump at an input 90a. Above that, the heat exchanger <NUM> is provided with a heat exchanger output 90b which is also connected to the heat pump <NUM>. Additionally, the heat exchanger <NUM> has a further heat exchanger output 90c to the further heat exchanger <NUM> and a further input 90d from the <NUM>-way valve <NUM>.

In the first mode, when the first operating mode is the bypass mode, the input 90a into the heat dissipation device <NUM>, i.e. into the region to be heated is directly connected to the return from the region to be cooled via the switching means of the heat pump, as shown, for example in <FIG>. If, however, the first operating mode is the free cooling mode, then the heat pump output 90a, which is at the same time the input into the heat exchanger <NUM>, is connected to the condenser output 12b.

In the embodiment shown in <FIG>, the temperature sensor means includes the temperature sensor <NUM> that is shown at the same position as illustrated in <FIG>.

Depending on the temperature signal at the temperature sensor <NUM>, a control indicated by <NUM> in <FIG> provides the control signal 36b, which is, in the embodiment shown in <FIG>, fed into an individual control <NUM> for the heat dissipation device <NUM>. Preferably, the control signal 36b is provided by the control <NUM> of the heat pump <NUM> such that the same can be fed indirectly into a control input <NUM> of the heat dissipation device, which is, although not shown in <FIG>, connected to a control input <NUM> of a controllable fan <NUM> which is part of the liquid/air-heat exchanger <NUM>. Alternatively or additionally, the control signal can be fed into a control input 85b of the pump <NUM> or into the control input 85c of the <NUM>-way valve.

It should be noted that the pump <NUM> can alternatively also be used in the forward, i.e. in the line 90c or that also an additional (controllable) pump can be used in the line 90c in addition to the pump <NUM>.

If the sensor <NUM> in the heat pump <NUM> determines that the liquid in the forward into the region to be cooled <NUM> is colder than a set value, the heat dissipation device <NUM> is controlled such that at least the return from the region to be heated via the line 90b becomes hotter. For that, the speed of the pump <NUM> can be reduced. Alternatively or additionally, the speed of the fan <NUM> can also be reduced. Alternatively or additionally, the <NUM>-way valve can be controlled such that a greater portion of the agent fed into the heat exchanger <NUM> via the input 90d originates directly from the output 90c and less agent originates from the heat exchanger <NUM>. It should be noted that it is sufficient that in the heat dissipation device merely either the fan or the pump or the <NUM>-way valve exist and are controlled, respectively. Already one controllable element influencing the heat dissipation and influencing the temperature of the return 90b of the heat exchanger <NUM>, respectively, is sufficient to obtain the desired functionality, i.e. that when it becomes too cold in the region to be heated, this coldness does not enter directly into the heat pump and then into the region to be cooled in the bypass mode or in the free cooling mode. Both in the bypass mode and possibly in the free cooling mode, the output signal of the sensor <NUM> can additionally be used for controlling the temperature raiser such that when the temperature raiser is constructed as radial compressor with a radial impeller, the speed of the radial impeller is increased or reduced, respectively, depending on the requirements.

In one implementation, the control <NUM> is configured to compare a temperature of the temperature sensor means, for example of the temperature sensor <NUM> or a temperature sensor <NUM>, to a set temperature, such that by the control signal, the speed of the radial compressor is increased or reduced depending on a deviation of the temperature from the set value. Preferably, a linear continuous control is used, wherein, however, increments of less than <NUM> % of the entire speed stroke also allow very fine control and can be used.

Alternatively, the speed of the radial compressor in the temperature raiser <NUM> can also be controlled by a temperature on the condenser side, such as for example the sensor <NUM> in <FIG>. In particular, the sensor <NUM> allows a two-fold application. In the normal mode, the same controls the speed of the radial impeller in the radial compressor while the same controls the heat dissipation device <NUM> in the bypass mode when the radial compressor is deactivated. Depending on the implementation, in the free cooling mode also exclusively the radial impeller can be controlled or also, as far as it is necessitated, the heat dissipation device can be controlled in addition to the control of the radial impeller.

The control of the individual elements in the heat dissipation device <NUM> preferably takes place proportionally or indirectly proportionally, depending on the control characteristic. Above that, continuous control or again discrete control is performed, but in increments that are each less than <NUM> % of the entire control strokes.

<FIG> shows a further embodiment of a heat pump where the heat exchanger <NUM> at the end of the heat pump on the evaporator side as well as the heat exchange <NUM> at the end of the heat pump on the condenser side are part of the heat pump, such that the return from the region to be cooled is the terminal 15c of the heat exchanger <NUM> and the forward into the region to be cooled is the terminal 15d of the heat exchanger <NUM>. Above that, the forward into the region to be heated is the terminal 17c of the heat exchanger and the return from the region to be heated is the terminal 17d of the heat exchanger. Thus, the heat exchangers <NUM> and <NUM> provide the outer terminal region for the heat pump. Above that, input switches <NUM> are connected between the heat exchangers and the actual evaporator and the actual condenser <NUM>, respectively, as shown in <FIG>. Further, the control <NUM> is provided to perform, in dependence on various temperature signals, such as an evaporator temperature signal provided by the sensor <NUM>, fine control of the compressor 36a and the heat dissipation device, respectively, via the control signal 36b in the free cooling mode on the one hand and in the normal mode on the other hand with respect to the bypass mode on the other hand. Above that, the control <NUM> receives a condenser-side sensor signal, for example from the sensors <NUM>, <NUM>. The sensor <NUM> is arranged in the condenser outlet 12d, while the sensor <NUM> in the free cooling mode represents the condenser inlet.

The input switch <NUM> and the output switch <NUM> fulfill the functionalities of the bypass elements <NUM>, <NUM>, <NUM>, <NUM> of <FIG> or <FIG> as well as the switches I, II, III IV of <FIG>, such that the heat pump shown in <FIG> can also run in the bypass mode, in the free cooling mode and in the normal mode with one or two stages, especially since the inner heat pump symbolically illustrated by the evaporator <NUM>, the compressor <NUM>, the condenser <NUM> and the feedback element <NUM> can consist of two or several connectable stages.

This is shown in tabular form in <FIG>. If the condenser temperature is within a very cold temperature range, as a response, the first operating mode is set by the control <NUM>. If it is determined in that mode that the evaporator temperature is lower than a set temperature, reduction of the heat dissipation is obtained by the control signal 36b in the heat dissipation device shown in <FIG>. If the condenser temperature is in the medium-cold range, as a response, switching into the free cooling mode by the control <NUM> is to be expected. If the evaporator temperature is greater than a set temperature, this results, as a response, in an increase of the speed of the radial compressor via the control line 36a. If it is again determined that the condenser temperature is in a hot temperature range, as a response, the first stage is set into normal operation. If it is again determined that at a specific speed of the compressor the evaporator temperature is still greater than a set temperature, this results in an increase of the speed of the first stage, again via the control signal 36a. If it is finally determined that the condenser temperature is in a very hot temperature range, as a response, a second stage is connected in the normal operation. Depending on whether the evaporator temperature, i.e. for example the temperature at the sensor <NUM> in <FIG> is greater or lower than a set temperature, control of the first and/or second stage is performed in order to respond to a changed situation.

It should be noted that the temperature ranges "very cold", "medium cold", "hot", "very hot" represent different temperature ranges whose respective average temperature rises from very cold to medium-cold, to hot, to very hot. The ranges can be directly adjacent as illustrated based on <FIG>. In embodiments, however, the ranges can also overlap and can be at the stated temperature level or another temperature level that is all in all higher or lower. Further, the heat pump is preferably operated with water as operating agent. Depending on the requirements, other agents can be used.

<FIG> shows a detailed illustration of switches <NUM> and <NUM> with the respective inputs/outputs as illustrated in the overall context in <FIG>.

The table in <FIG> shows which inputs are in the respective modes with which outputs in the respective switches.

In particular, the input switch <NUM> includes a first input 15a, a second input <NUM>, a third input 16b (corresponding to the fourth connecting line 16b of <FIG>) and a fourth input 10b. Above that, the input switch also includes four outputs, namely the first output <NUM>, the second output 14b (corresponding to the second connecting line 14b of <FIG>), the third output 10a and the fourth output 15b.

The output switch again includes a first input 17b, a second input <NUM>, a third input 14b (corresponding to the second connecting line 14b of <FIG>) and a fourth input 12b and again a first output <NUM>, a second output 16b (corresponding to the fourth connecting line 16b of <FIG>), a third output 12a, and a fourth output 17a.

In the bypass mode, the input switch is switched such that the first input is connected to the first output (15a-<NUM>). Further, the fourth output 15b is connected to the second input <NUM> (15b-<NUM>).

With regard to the output switch <NUM>, the first input is connected to the first output (17b-<NUM>). Further, the second input <NUM> is connected to the fourth output 17a (<NUM>-27a).

In the free cooling mode, the following connections exist in the input switch. The first input is connected to the second output 14b (15a-14b) and the third input 16b is connected to the third output 10a (16b-10a). In the output switch <NUM>, again, the first input 17b is connected to the second output 16b and further, the third input 14b is connected to the third output 12a.

In the normal mode again, in the input switch <NUM>, the first input is connected to the third output (15a-10a). Above that, the fourth output 15b is connected to the fourth input 10b (15b-10b). In the output switch <NUM> again, in the normal mode, the first input 17b is connected to the third output 12a and further, the fourth output 17a is connected to the fourth input 12b (17a-12b).

In the normal mode where a second stage is activated, the connections are identical as illustrated in the last line of <FIG>.

The respective connection in the switches <NUM>, <NUM> can be implemented, for example as in <FIG> with simple switches that are arranged in a cascaded manner or by a more flexible "switching matrix" in order to obtain the necessitated liquid connection of a respective input to a respective output and to prevent liquid connection between the other inputs/outputs.

The heat pump shown in <FIG> implements all three aspects, namely on the one hand the aspect of switching between the bypass mode and the free cooling mode or normal mode. The heat pump in <FIG> also implements the second aspect, namely the double usage of the temperature sensor on the evaporator side on the one hand, in the bypass mode, for heat dissipation device control, and, on the other hand, in the free cooling and in particular the normal mode for compressor control. The heat pump in <FIG> also implements the third aspect, namely the usage of two different temperature sensors, namely the "bottom" temperature sensor close to the evaporator whose output signal is merely used for controlling the compressor on the one hand or the heat dissipation device on the other hand, but does not affect any mode switching. In contrast, temperature measurements on the condenser side, such as by the sensors <NUM>, <NUM> is used for obtaining mode switching, wherein, however, the output signals of these sensors do not obtain any compressor control and heat dissipation control in the heat dissipation device, respectively.

The three stated inventive aspects can be used together as shown in <FIG>. The aspects can however also be used individually or in pairs.

Although specific elements are described as device elements, it should be noted that this description can equally be considered as a description of steps of a method and vice versa. For example, the block diagram shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> also represents a flow diagram of a respective inventive method.

Claim 1:
Heat pump, comprising:
an evaporator (<NUM>) with an evaporator inlet (10a) and an evaporator outlet (10b);
a temperature raiser (<NUM>) for raising a temperature of an evaporated operating liquid;
a condenser (<NUM>) for condensing an evaporated operating liquid with raised temperature;
a temperature sensor means (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) with a first temperature sensor (<NUM>, <NUM>, <NUM>) for detecting a temperature with regard to the evaporator (<NUM>) and with a second temperature sensor (<NUM>, <NUM>) for detecting a temperature at the condenser (<NUM>);
a switching means (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) wherein the switching means (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is configured to operate the heat pump in a first operating mode or a different second operating mode, wherein the first operating mode is a bypass mode and wherein the second operating mode is a normal mode,
wherein the switching means (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is configured to connect, in the bypass mode, a return (15b) of a region to be cooled (<NUM>) to a forward (17a) of a region to be heated (<NUM>) and to connect a return (17b) of the region to be heated (<NUM>) to a forward (15a) of the region to be cooled (<NUM>); and
a control means (<NUM>) for controlling the switching means (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) so that the switching means (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) operates in the first operating mode or the second operating mode based on an output signal of the second temperature sensor (<NUM>, <NUM>) and for controlling the temperature raiser (<NUM>) based on an output signal of the first temperature sensor (<NUM>, <NUM>, <NUM>).