EP-4735808-A1 - HEAT PUMP AND METHOD FOR OPERATING SAME

Abstract

The invention relates to a heat pump (1) comprising a working-fluid circuit having an evaporator (2) which forms a liquid-receiving volume (13) in the bottom region and a vapour-receiving volume (14) in the top region, a compressor (3) adjoining the evaporator (2), a condenser (4) adjoining the compressor (3), and an expansion unit (6) adjoining the condenser (4), which expansion unit is connected to the evaporator (2), characterised in that a line (11, 12) connecting the expansion unit (6) to the evaporator (2) is routed through the vapour-receiving volume (14) of the evaporator before opening in the evaporator (2). The invention further relates to a method for operating a heat pump (1) of this kind.

Inventors

• HELL, Emil
• Mazur, Oskar

Assignees

• Siemens Energy Global GmbH & Co. KG

Dates

Publication Date

20260506

Application Date

20240719

Claims (6)

1. 1. Heat pump (1) comprising a working fluid circuit having an evaporator (2) which forms a liquid absorption volume (13) in the lower region and a vapor absorption volume (14) in the upper region, a compressor (3) connected to the evaporator (2), a condenser (4) connected to the compressor (3) and an expansion unit (6) connected to the condenser (4) and connected to the evaporator (2), characterized in that a line (11, 12) connecting the expansion unit (6) to the evaporator (2) is guided through the vapor absorption volume (14) of the evaporator (2) before it opens into the evaporator (2).
2. 2. Heat pump (1) according to claim 1, characterized in that a line (11, 12) connecting the expansion unit (6) to the evaporator (2) is designed as a bundle of lines (18) or as a meandering line in the region which is guided through the steam receiving volume (14) of the evaporator (2).
3. 3. Heat pump (1) according to claim 1 or 2, characterized in that the expansion unit (6) has a throttle valve (26), an expansion tank (27) arranged downstream of the throttle valve (26), which forms a liquid receiving volume (28) and a vapor receiving volume (29), and a further throttle valve (30) arranged downstream of the expansion tank (6).
4. 4. Heat pump (1) according to claim 3, characterized in that a demister (31) is positioned in the steam receiving volume (29) of the expansion tank (27) and above the demister (31) a line (32) connecting the expansion tank (27) to the compressor (3) leads out of the expansion tank (27).
5. 5. Heat pump (1) according to one of the preceding claims, characterized in that the steam receiving volume (14) of the evaporator (2) and the condenser (4) are connected to one another via a bypass line (34) provided with a bypass valve (33).
6. 6. Method for operating a heat pump (1), in particular a heat pump according to one of the preceding claims, in which a working fluid circulates, characterized in that working fluid vapor present within a vapor receiving volume (14) of an evaporator (2) of the heat pump (1) is superheated by heat exchange with working fluid condensate conducted from an expansion unit (6) of the heat pump to the evaporator (2) before it is conducted to a compressor (3) of the heat pump (1).

Description

Description Heat pump and method for operating such a pump The invention relates to a heat pump comprising a working fluid circuit having an evaporator which forms a liquid receiving volume in the lower region and a vapor receiving volume in the upper region, a compressor connected to the evaporator, a condenser connected to the compressor and an expansion tank connected to the condenser which is connected to the evaporator, wherein throttle valves are provided in lines which connect the condenser to the expansion tank and the expansion tank to the evaporator. Furthermore, the invention relates to a method for operating such a heat pump. Heat pumps of the type mentioned at the beginning are known in the prior art in a wide variety of designs. They comprise a working fluid circuit, the main components of which are an evaporator, a compressor, a condenser and an expansion unit. In the evaporator, the working fluid is heated by an external heat source and evaporated. It is then fed to the compressor and brought to a higher pressure level there. The working fluid is then liquefied in the condenser at a condensation temperature that is higher than the evaporation temperature. In order to return the working fluid to its original state at the end of the circuit, it is expanded in the expansion unit, which lowers its temperature again. Small liquid droplets can be entrained in the vapor stream generated within the evaporator and fed to the compressor. If the droplets are too large, they can cause damage to the compressor. To avoid such damage, it has already been proposed to install a demister in the vapor intake volume of the evaporator, which separates the droplets from the vapor mass flow, whereupon they drip back into the liquid intake volume of the evaporator. Based on this prior art, it is an object of the present invention to provide a heat pump of the type mentioned at the outset with an alternative structure and an alternative method for operating such a heat pump. To solve this problem, the present invention creates a heat pump comprising a working fluid circuit having an evaporator, which forms a liquid absorption volume in the lower area and a steam absorption volume in the upper area, a compressor connected to the evaporator, a condenser connected to the compressor and an expansion unit connected to the condenser, which is connected to the evaporator, characterized in that a line connecting the expansion unit to the evaporator is led through the steam absorption volume of the evaporator before it opens into the evaporator. Thanks to such a structure, the working fluid led from the expansion unit to the evaporator can be used to overheat steam contained in the steam absorption volume of the evaporator, whereby drops contained in the steam are evaporated and cannot reach the compressor. The heat pump according to the invention is characterized by on the one hand, because the installation of a demister in the evaporator can be completely dispensed with. On the other hand, the coefficient of performance (COP) of the heat pump can be improved by around 5 to 7%, since additional heat is extracted from the working medium, which was previously only expanded on the way from the expansion unit to the evaporator. Preferably, the line which connects the expansion unit to the evaporator is designed as a bundle of lines or as a meandering line in the region which runs through the vapor absorption volume of the evaporator in order to release heat to the vaporous working fluid as evenly and/or as widely as possible. According to one embodiment of the present invention, the expansion unit has a throttle valve, an expansion tank arranged downstream of the throttle valve, which forms a liquid receiving volume and a vapor receiving volume, and a further throttle valve arranged downstream of the expansion tank. Accordingly, the pressure of the condensed working fluid coming from the condenser can initially be reduced by means of the first throttle valve to a first pressure level at which it is stored in the expansion tank in both liquid and gaseous form. Using the further throttle valve, the pressure can then be reduced to a second pressure level before the working fluid enters the evaporator. It is advantageous to position a demister in the steam receiving volume of the expansion vessel, and above the demister misters leads a line connecting the expansion tank with the compressor out of the expansion tank. Accordingly, the vaporous working fluid contained in the expansion tank can be led directly to the compressor without having to pass through the evaporator, thereby improving the performance coefficient of the heat pump. Preferably, the vapor absorption volume of the evaporator and the condenser are connected to one another via a bypass line provided with a bypass valve. Accordingly, the compressor can be bypassed if necessary. Furthermore, in order to achieve the object mentioned at the outset, the present invention