DE102017107451A1 - Heat pump system and method for defrosting an evaporator of the heat pump system - Google Patents

Abstract

The present invention relates to a heat pump system for temperature control and / or ventilation of rooms and / or buildings, with a ventilation unit, the air / air heat exchanger (200) and an associated exhaust duct (210), a supply air duct (220), an exhaust duct (250) and an outside air channel (280), and a heat pump unit with a refrigerant circuit (100) and an evaporator (160), wherein the evaporator (160) can be supplied with external air via an opening and an associated method. The exhaust air duct (250) forms an air duct to the evaporator (160), which is set up such that exhaust air flowing through the exhaust air duct (250) is guided via the evaporator (160). This helps to defrost the evaporator (160).

Description

The present invention relates to a heat pump system for temperature control and / or ventilation of rooms and / or buildings and a method for defrosting an evaporator of a heat pump unit of such a heat pump system.

In particular, the present invention relates to a heat pump system with a ventilation unit having an air / air heat exchanger and an associated exhaust duct, a supply air duct, an exhaust air duct and an outside air duct, and a heat pump unit with a refrigerant circuit and an evaporator, wherein the evaporator via an opening Outside air can be supplied.

The ventilation unit serves to equalize a heat level of the fresh air flowing into rooms or buildings via the outside air duct and the exhaust air flowing out of the rooms or buildings, in order to reduce the energy losses associated with the ventilation. As a result, the temperature of the exhaust air is less far removed from the temperature of the outside air, for example in the range less K.

It is known to further heat the outside air used for ventilation of the rooms or buildings after flowing through the air / air heat exchanger by energy that has been promoted by the heat pump unit or cooling in other cases, the supply air to the for the ventilation to bring desired temperature. In this case, as is known for the use of heat pump units, icing of the evaporator of the heat pump unit may occur.

The evaporator must be defrosted in these cases, for example by reversing the refrigerant circuit or by using electrical heating power. All of the active defrosting methods of the evaporator cost energy and reduce the coefficient of performance of the heat pump system, which is undesirable and justifies the desire to avoid such defrosting operations.

The present invention was therefore based on the object to avoid icing of the evaporator of the heat pump unit of a heat pump system mentioned above or at least delay.

According to the invention the object is achieved in a heat pump system of the type mentioned above in that the exhaust air duct forms an air channel to the evaporator, which is set up so that exhaust air flowing through the exhaust duct is passed through the evaporator.

The exhaust air flow is preferably cooled in the air / air heat exchanger in the case of heating operation to a temperature which is below the room / building temperature. Nevertheless, this will then have the air / air heat exchanger leaving the exhaust air leaving a temperature which is above the temperature of the outside air, for example about 2 K to 7 K above the temperature of the outside air or the air, the air / air heat exchanger. Heat exchanger is supplied. Thus, the exhaust air over the outside air has a higher energy, which advantageously results in the arrangement according to the invention that higher-energy air is passed through the evaporator. The higher energy air helps to defrost the evaporator, at least by reducing the rate of icing. At the same time, the efficiency is further increased by the fact that not the more energetic exhaust air but the exhaust air is passed through the evaporator after flowing through the air / air heat exchanger.

In one embodiment, the ventilation unit is set up such that exhaust air flowing through the exhaust air duct has a temperature of at least 3 ° C. Preferably, this can be ensured that the exhaust air passed through the evaporator shows a beneficial effect for the defrosting of the evaporator.

In one embodiment, the exhaust air flowing through the exhaust duct is configured to assist in defrosting the evaporator. This is the result of the advantageous combination of the arrangement of the exhaust air duct so that exhaust air is passed through the evaporator, as well as the energy content of the exhaust air, which is due to the air / air heat exchanger regularly above the energy content of the outside air, with the via the evaporator Guided air is preferably mixed.

In one embodiment, the air / air heat exchanger is designed as a cross countercurrent heat exchanger. This allows a particularly effective heat transfer between outside air or supply air in the one stream and exhaust air or exhaust air in the countercurrent. Of course, other suitable heat exchangers or heat exchangers are applicable accordingly.

In one embodiment, the outside air duct has a preheater, which is set up, outside air flowing through the outside air duct to a value of at least -5 ° C, preferably to a value between -5 ° C and +1 ° C, and particularly preferably to a value from about -3 ° C, to warm. This will ensure that the Temperature of the exhaust air a preferred minimum value, for example 3 ° C, does not fall below. At the same time, the risk is reduced that condensate freezing in the air / air heat exchanger freezes.

In one embodiment, the heat pump system further comprises a heater buffer unit for providing a heat buffer for temperature control and / or ventilation of rooms, the heater buffer unit having a buffer memory configured as stratified storage and a charging circuit providing a flow circuit for a heat transfer medium. The charging circuit includes a first heat exchanger for receiving heat from the heat pump unit and a primary flow path to the heater buffer unit. The ventilation unit has an air heater in the supply air duct, wherein the air heater is coupled to the heating buffer unit.

The heating buffer unit ensures a permanent supply of energy, wherein the supply air is preferably always brought by the energy of the heating buffer unit to the desired temperature. At the same time, the heating buffer unit then ensures that the exhaust air reaching the air / air heat exchanger has a certain minimum energy, so that the exhaust air leaving the air / air heat exchanger also has the necessary energy to support defrosting of the evaporator ,

In one embodiment, the air heater is adapted to heat the supply air to a temperature dependent on the outside air, in particular to a range of 30 ° C to 60 ° C, wherein the supply air is heated to a lower temperature for higher temperatures of the outside air. A higher demanded heating power, i. due to low temperature of the outside air, is implemented by increasing the temperature of the supply air. At the same time it is thus ensured that the temperature of the exhaust air after passing through the air / air heat exchanger does not fall below the desired value, i. previously have an appropriate energy reserve.

In one embodiment, a supply air fan is arranged in the supply air duct and arranged in the exhaust duct an exhaust fan. It is advantageous to suck the supply air and the exhaust air thus each of the air through the air / air heat exchanger, i. to arrange the respective fan in the flow path after the air / air heat exchanger.

The object is further achieved by a method for defrosting an evaporator of a heat pump unit of the type mentioned. The method includes passing the exhaust air flowing through the exhaust air passage over the evaporator to assist in defrosting the evaporator.

• 1 schematisch und exemplarisch eine Wärmepumpenanlage gemäß der Erfindung.

Advantages and embodiments will be described below with reference to the accompanying drawings. Hereby show:

• 1 schematically and exemplarily a heat pump system according to the invention.

The proposed heat pump system 1 is a combination of a heat generator for heating, cooling and a ventilation system for the temperature control of rooms and / or buildings. The heat pump system 1 contains a refrigerant circuit 100 , an air / air heat exchanger 200 , a hot water tank 300 and a buffer memory 610 , In a charging cycle 700 can be via a three-way valve 710 Hot water or heating / cooling of rooms done.

In particular, a solar system 400 and / or an electric heater 500 are to the heat pump system 1 connectable or integrable.

The heat pump system 1 is in the embodiment of two units composed of a heating module 2 and a memory module 3 , The modules 2 . 3 are assembled in a building / room and form the heat pump system 1 , for heating for hot water and for ventilation, optionally also for cooling.

The heat pump system 1 has a refrigerant circuit 100 with a compressor 110 , a three-way valve, a gas cooler, a refrigerant subcooler, a throttle 150 and an evaporator 160 on.

Furthermore, a gas cooler is advantageous 170 provided, a heat exchanger 171 for a heat exchange between a refrigerant of the refrigerant circuit 100 and a heat transfer medium of a charging circuit 700 having. The evaporator 160 is an opening 161 assigned over which the evaporator 160 is connected to an outside air.

Furthermore, the refrigerant circuit 100 cables 180 . 184 and 185 on.

In 1 is still an air / air heat exchanger 200 in the heat pump system 1 involved. The air / air heat exchanger 200 is to an exhaust duct 210 , a supply air duct 220 , an exhaust duct 250 and an outside air duct 280 connected. In the supply air duct 220 is preferably a supply air fan 221 arranged. An exhaust fan 251 is preferably in the exhaust air duct 250 arranged.

Outside air AU is the air / air heat exchanger 200 via a preheater 270 fed. In the preheater 270 the outside air AU is preferably heated to a minimum temperature value tM. The minimum temperature value tM is in one embodiment preferably at about -3 ° C, but at least at about -5 ° C or at a value between -5 ° C and +3 ° C. The minimum temperature value tM may in another embodiment also depend on an air parameter, in particular on the outside air AU. The minimum temperature tM can be determined by the moisture content and / or the temperature of the outside air AU, by the moisture content of the preheater 270 air or other values.

The preheater 270 supplied air can be outside air AU, a mixture of outside air AU and exhaust air FO or even just exhaust air FO or come from other sources. The minimum temperature tM should preferably be in a temperature range between -3 ° C and 0 ° C and may be the described dependence on the temperature of the outside air AU and / or on the humidity of the preheater 270 be supplied air. At very low temperatures and with very low humidity, the minimum temperature tM can be lowered rather than increased at high moisture contents, eg to temperatures above the freezing point, in particular 1 ° C to 3 ° C. About the outside air duct 280 the air then flows further from the preheater 270 to the air / air heat exchanger 200 ,

In the air / air heat exchanger 200 The outside air AU is further heated by heat from the air / air heat exchanger 200 heated exhaust air AB of a room heated. The exhaust air AB of the room is about 15-25 °, in particular about 20 °, and heated with preferably at least the minimum temperature of about -5 ° C to 3 ° C, in particular -3 ° C in the air / air heat exchanger 200 incoming outside air AU to temperatures between at least 1 ° C to about 20 ° C on. The outside air AU is preferably countercurrently raised to a temperature which is about 2 K to 5 K below the temperature of the exhaust air AB from the room.

Next, the then heated outside air AU flows to the air / air heat exchanger 200 as supply air CLOSED via the supply air duct 220 to an air heater 230 ,

In the air heater 230 the supply air ZU is raised to a second temperature tGa, which represents a required temperature for the heating of the room. That by the air heater 230 flowing heat transfer medium there has temperatures tW of preferably 30 ° C - 70 ° C, whereby the supply air flow ZU is raised to a temperature of preferably below 60 ° C, in particular approximately less than / equal to 50 ° C.

The setpoint temperature of the supply air flow ZU is controlled as a function of an outside temperature tAu and / or a room temperature. Accordingly, either the mass flow of the heat transfer medium through the air heater 230 and / or the temperature tW of the heat transfer medium controlled to reach the second temperature tGa. Preferably, according to 2 a supply air temperature sensor in a supply air connection 240 provided that detects the supply air tZu. Depending on a temperature signal of the supply air tZu and / or the room temperature tR and / or the outside temperature tAu, the temperature of the heat transfer medium and / or the mass flow of the heat transfer medium is controlled.

At outdoor temperatures in the range of -20 ° C, the supply air is heated to approx. 50 ° C. At temperatures of around 0 ° C, the supply air warms up to around 35 ° C.

In a cooling case, when the building is to be cooled, the supply air ZU is lowered in temperature to a value lower than the room temperature tR. This takes place until the setpoint of the room temperature tRs is reached. In many cases of cooling, it is necessary that the supply air temperature for cooling longer times, especially over several hours, in which the outside temperature is above 25 ° C or a strong heat input by solar radiation is maintained below the set temperature of the room tRs and the heat transfer medium is cooled , This is also the refrigerant circuit 100 operated such that the gas cooler 170 serves as a gas heater or evaporator, where the refrigerant absorbs heat from the heat transfer medium and thus cools the heat transfer medium.

The exhaust air flow AB, through the exhaust air duct 210 to the air / air heat exchanger 200 flows, is in the heating case by the cool outside air flow AU, preferably at about -3 ° C to 2 ° C to the air / air heat exchanger 200 flows, cooled to temperatures below room temperature. Depending on the outside temperature, cooling takes place to a temperature value which is approx. 2 K to 7 K above the outside air temperature or the temperature of the air which is the air / air heat exchanger 200 is supplied, is. The exhaust air AB thus flows cooled as exhaust air FO from the air / air heat exchanger 200 from and is preferably in the embodiment by the exhaust fan 251 promoted.

The thus extracted exhaust air FO is via an exhaust air duct 250 an evaporator 160 of the refrigerant circuit 100 fed. Since the exhaust air FO, with about 2 K to 7 K, is warmer than the outside air AU, the evaporator will 160 supplied by the exhaust air FO relatively high-energy air, which preferably has a temperature above the freezing point, which a freeze of the evaporator 160 avoided or delayed.

At standstill of the refrigerant circuit 100 can with the exhaust FO of the evaporator 160 be defrosted.

In the exemplary embodiment, the heat pump system 1 continue a hot water tank 300 on, preferably via a hot water heat exchanger 330 is heated. By means of a circulating pump 320 which is in a pump line 340 is, is in the hot water tank 300 located drinking water through the hot water heat exchanger 330 pumped. The drinking water preferably flows through the water pipes 341 and 342 to the hot water heat exchanger 330 who is in a corpus 310 is arranged.

The heat transfer medium is by means of the pump 720 to the hot water heat exchanger 330 pumped.

The three-way valve we from the regulator 4 switched between hot water and buffer storage. For hot water loading is the three-way valve 710 switched so that the heat transfer medium to the hot water heat exchanger 330 is headed. For heating the buffer tank and / or the heat carrier circuit 600 is the three-way valve to the primary flow line 701 open.

In one embodiment, a solar system 400 to the heat pump system 1 connected. The solar system 400 consists of a solar collector 410 , a solar pump 420 , a solar heat exchanger 430 as well as a solar heat transfer medium cooler 431 , The solar heat transfer medium cooler 431 is preferably in a return line 730 a charging circuit 700 involved.

An electric heater 500 with an electric radiator 510 and an electrical connection 520 is designed to convert direct electrical current into heat and transfer this heat to the charging circuit 700 to be able to deliver.

According to 1 is still a buffer memory 610 provided to the a heat transfer circuit 600 connected. A fluid line 612 leads to the air heater 230 ,

In the cache 610 is a first buffer tube in the embodiment 6110 intended. The cache 610 has a first entry 6111 and a first exit 6112 on.

In the embodiment, the first buffer tube 6110 with a first pipe opening 6113 fitted. The first pipe opening 6113 is up to an upper dished bottom 6130 directed. The first buffer tube 6110 itself is opposite the first pipe opening 6113 advantageously at least partially through, so that one through the first buffer tube 6110 flowing heat transfer medium with that in the buffer tank 610 located heat transfer medium on the upper dished bottom 6130 directed first pipe opening 6113 communicates.

This is a fluidic connection between the first entry 6111 and the first exit 6112 of the first buffer tube 6110 intended. The heat transfer medium thus passes through the first entrance 6111 in the cache 610 and flows in the first buffer tube 6110 to the first pipe opening 6113 , As far as a buffer pump 620 runs, the heat transfer medium is promoted. It flows through the first pipe opening 6113 in the cache 610 and the so-promoted heat transfer medium flows largely directly through the first exit 6112 of the first buffer tube 6110 in the heat transfer circuit 600 , Depending on with what capacities the buffer pump 620 and a charge pump 720 run, the heat transfer medium is partially or completely in the buffer memory 610 pumped. At about the same capacity of the pumps 620 . 720 The heat transfer medium flows directly from the first inlet 6111 to the first exit 6112 and through the first pipe opening 6113 flows as good as no heat transfer medium in the buffer memory 610 , As far as the buffer pump 620 For example, promotes less heat transfer medium than the charge pump 720 , There is a flow distribution of the heat transfer medium on the one hand in the first exit 6112 according to the capacity of the buffer pump 620 and on the other hand into the buffer memory 610 itself. The difference in the mass flow of the heat transfer medium, depending on the delivery rate of the charge pump 720 and the buffer pump 620 , flows through the first pipe opening 6113 in or out of the buffer memory 610 , Thus, the heat transfer medium with the temperature TW of the heat transfer medium in the buffer memory 610 transported and this layered from top to bottom with this temperature TW loaded or unloaded. The heat transfer medium flows with the temperature TW in the heat transfer circuit 600 ,

The cache 610 has in the embodiment according to 1 a second buffer tube 6120 on. The cache 610 is with a second entry 6121 and a second exit 6122 fitted. The second buffer tube 6120 has a second pipe opening 6123 on, leading to a lower dished bottom 6150 is directed and thus the second buffer tube 6120 to the lower dished bottom 6150 is open. Opposite the second pipe opening 6123 is the second buffer tube 6120 continuously.

The first buffer tube 6110 and the second buffer tube 6120 are continuous in the embodiment, but each have the pipe opening 6113 . 6123 , Essential here is not the continuity of the tube, but the best possible flow from the first entry 6111 to the first exit 6112 which can also be achieved by other means, but is particularly advantageous.

Thus, in another embodiment, instead of a continuous buffer tube 6110 also two tubes are used which are preferably opposite each other in the buffer memory 610 are arranged and advantageously a flow protection 6160 have, which prevents turbulence or oblique flows, the stratification of the heat transfer medium at the temperature of the heat transfer medium TW in the buffer memory 610 is disturbed.

The cache 610 points between the upper dished bottom 6130 and the lower dished bottom 6150 a container wall 6140 on. The cache 610 has a diameter D and a height H. Furthermore, the cylinder wall by a height HZ of the cylinder wall 6140 Are defined. The distance of the first buffer tube 6110 to the second buffer tube 6120 is defined by a buffer pipe distance R

The cache 610 is designed very slim, ie the ratio of the buffer diameter D to the height H of the buffer memory is low. The cache 610 has a diameter D of advantageously about 15 cm - 25 cm, wherein the height H is advantageously between about 80 cm and 200 cm, wherein the ratio of diameter and height D / H in the embodiment is preferably less than 0.2.

The diameter D may also be smaller than 15 cm in other embodiments and the height H may be even higher than 200 cm. Depending on how high the height H is selected, the diameter D can also be larger. As far as the height H exceeds 200 cm, the diameter D may be more than 25 cm, wherein the ratio of diameter and height preferably remains smaller than 0.3 or smaller than 0.2.

In the embodiment, the diameter D of the buffer memory 610 about 18 cm and the height about 150 cm. Thus, the ratio of the buffer memory diameter D to the height H of the buffer memory 610 advantageously about 0.12. Advantageously, such ratios of the diameter D to the height H will be less than 0.4, in particular ratios between 0.2 and 0.08, or about 0.1 to 0.14.

In the heat transfer circuit 600 is the buffer pump 620 provided, the heat transfer medium first to Lufterhitzter 230 and then to a Heizkreiswärmeübertrager 632 haunts. The heating circuit heat exchanger 632 is part of a heating circuit 630 , The heating circuit 630 is traversed by a liquid heat transfer medium, driven by a heating circuit pump 631 , This can be a floor heating and / or radiators are supplied with heat / cold.

In the area of water hydraulics of the buffer tank 610 is a buffer bypass 703 provided by a primary flow line 701 by means of a bypass three-way valve 702 is branched off.

At the preheater ( 270 ) bypassing is advantageously a bypass ( 272 ), which has a bypass three-way valve ( 271 ) can be opened or closed.

In an advantageous method step, the bypass ( 272 ) flows through the heat transfer medium when the outside air AU already has a minimum temperature value tM. Thus, depending on the outside temperature tAu the preheater ( 270 ) flowed through by heat transfer medium or not. As far as the outside temperature tAu is lower than the temperature minimum value tM, the bypass ( 272 ) with the three-way valve ( 271 ) and the heat transfer medium flows through the preheater ( 270 ) to bring the outside air AU to the minimum temperature tAu.

A cache 610 for a heat pump system 1 , with a volume for receiving a heat transfer medium, has a height H, a diameter D and at least one inlet ( 6111 . 6121 ) and at least one exit ( 6112 . 6122 ). The cache 610 has inside a ratio between the diameter D and a height H of less than 0.4, in particular less than about 0.2.

The container wall 6140 is between the upper dished bottom 6130 and the lower dished bottom 6150 arranged, wherein the upper buffer tube 6110 below the upper dished bottom 6130 through the container wall 6140 is guided and the lower buffer tube 6120 above the lower dished bottom 6150 through the container wall 6140 is guided.

Advantageously, at least one buffer tube 6110 . 6120 an opening 6113 . 6123 ) and is to a dished bottom 6130 . 6150 directed towards.

Claims (9)

Heat pump system for temperature control and / or ventilation of rooms and / or buildings, with - a ventilation unit which has an air / air heat exchanger (200) and an exhaust air duct (210), an air inlet duct (220), an exhaust air duct (250) and an outside air duct (280), - a heat pump unit with a refrigerant circuit (100) and an evaporator (160), wherein outside air can be fed to the evaporator (160) via an opening, characterized in that the exhaust air duct (250) forms an air duct to the evaporator (160), which is arranged such that through the exhaust air duct (250 ) flowing exhaust air over the evaporator (160) is guided. Heat pump system after Claim 1 wherein the ventilation unit is arranged such that exhaust air flowing through the exhaust air duct (250) has a temperature of at least 3 ° C. Heat pump system after Claim 1 or 2 wherein the exhaust air flowing through the exhaust duct (250) is configured to assist in defrosting the evaporator (160). Heat pump system according to one of the preceding claims, wherein the air / air heat exchanger (200) is designed as a cross countercurrent heat exchanger. Heat pump system according to one of the preceding claims, wherein the outer air channel (280) comprises a preheater (270) which is adapted to external air flowing through the outer air channel (280) to a value of at least -5 ° C, preferably to a value between -5 ° C and +1 ° C and more preferably to a value of about -3 ° C, to heat. Heat pump installation according to one of the preceding claims, further comprising: a heating buffer unit for providing a heat buffer for tempering and / or ventilating rooms, wherein the heating buffer unit has a buffer memory (610) which is designed as stratified storage, a charging circuit providing a flow circuit for a heat transfer medium, the charging circuit having a first heat exchanger (171) for receiving heat from the heat pump unit and a primary flow path to the heater buffer unit, the ventilation unit having an air heater (230) in the supply air duct (220). wherein the air heater (230) is coupled to the heater buffer unit. Heat pump system after Claim 6 wherein the air heater (230) is adapted to heat the supply air to a temperature dependent on the outside air, in particular to a range of 30 ° C to 60 ° C, wherein the supply air is heated to a lower temperature for higher temperatures of the outside air. Heat pump system according to one of the preceding claims, wherein in the supply air duct (220) a supply air fan (221) is arranged and wherein in the exhaust air duct (250) an exhaust air fan (251) is arranged. A method for defrosting an evaporator (160) of a heat pump unit of a heat pump system for temperature control and / or ventilation of rooms and / or buildings, the heat pump system comprising a ventilation unit comprising an air / air heat exchanger (200) and an exhaust duct (210) connected thereto, a supply air duct (220), an exhaust air duct (250) and an outer air duct (280), and a heat pump unit with a refrigerant circuit (100) and an evaporator (160), wherein the evaporator (160) can be supplied with external air via an opening, characterized in that the method comprises passing the exhaust air flowing through the exhaust duct (250) over the evaporator (160) to assist in defrosting the evaporator (160).

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