DE102022104420A1 - Refrigeration system for vehicles with at least one primary circuit and one secondary circuit - Google Patents

Abstract

The invention relates to a refrigeration system for vehicles, which has an interface to a cooling circuit of at least one component of the energy supply or drive system to be cooled (primary circuit), which has at least one heat exchanger for temperature control of the vehicle interior with the possibility of integration into the primary circuit and which has a refrigerant Circuit (secondary circuit) has, which can be operated both according to the compression refrigeration principle and according to the Organic Rankine (ORC) principle.

Description

The invention relates to a refrigeration system for vehicles with at least one primary circuit and one secondary circuit and is used in particular for rail vehicles.

In the pamphlet U.S. 6,880,344 B2 describes an energy recovery system using an ORC cycle with an evaporator. There is no known use of the evaporator for interior temperature control. Only one temperature/pressure level can be realized and no use on a vehicle is intended.

The pamphlets JP 2006 - 321 389 A (here in particular the third embodiment), U.S. 2019/0 128 146 A1 and DE 10 2005 032 277 A1 each represent refrigeration systems for mobile applications, which in the words of claim 1 have at least one primary circuit and one secondary circuit, the primary circuit being routed via a component of the energy supply or drive system to be cooled and the secondary circuit both after the cold vapor compression refrigeration process, and can also be operated according to the ORC process. However, in none of these inventions can a heat exchanger integrated into the primary circuit achieve temperature control of the vehicle interior both in cold vapor compression refrigeration operation and in ORC operation.

The invention represents a refrigeration system for vehicles, which combines the tasks of vehicle interior temperature control and energy recovery from the waste heat of the drive system.

These tasks are solved with the features of the first patent claim. Advantageous configurations result from the dependent claims.

• • mindestens eine Zulauf (Z) und ein Rücklauf (R) zu mindestens einer zu entwärmenden Komponente (1) des Energieversorgungs- bzw. Antriebssystems,
• • mindestens ein Wärmeübertrager (2) zum Sekundärkreis,
• • mindestens ein Wärmeübertrager (3) für die Fahrzeuginnenraumtemperierung und
• • mindestens eine Pumpe (P2).

According to the invention, the secondary circuit is designed in such a way that it represents a combination of ORC and compression refrigeration machine, since it can be operated both as a clockwise (conversion of heat energy into mechanical work) and as a counterclockwise (increase in the temperature utilization level by adding mechanical work) thermodynamic cycle .
The refrigeration system or refrigeration system for vehicles is constructed as follows: In a primary circuit, through which a working medium flows without phase transition (example, but not exclusively water-glycol mixture), there are

• • at least one inlet (Z) and one return (R) to at least one component (1) of the energy supply or drive system to be cooled,
• • at least one heat exchanger (2) to the secondary circuit,
• • at least one heat exchanger (3) for the temperature control of the vehicle interior and
• • at least one pump (P2).

In the 1 The pump P1 shown and the outdoor air heat exchanger (5) are used for the complete representation of the primary circuit.

• • mindestens ein Wärmeübertrager zum Primärkreis (2),
• • mindestens eine Kältemittelpumpe (P3),
• • mindestens eine Expansionsmaschine (T),
• • mindestens eine Kompressionsmaschine (K),
• • mindestens ein Wärmeübertrager, der als Verflüssiger des Kältemittels betrieben wird (4)
• • Mindestens ein Expansionsventil (E) und
• • mindestens einen Kältemittelsammler (S).

In a refrigerant circuit (secondary circuit), which can be operated both as a right-hand (ORC machine) and as a left-hand (compression refrigeration machine) thermodynamic cycle, are located at the same time

• • at least one heat exchanger to the primary circuit (2),
• • at least one refrigerant pump (P3),
• • at least one expansion machine (T),
• • at least one compression machine (K),
• • at least one heat exchanger that is operated as a condenser of the refrigerant (4)
• • At least one expansion valve (E) and
• • at least one refrigerant collector (S).

Advantageously, essential components of the secondary circuit, in particular the evaporator and condenser, can be used both for the clockwise and counterclockwise thermodynamic cycle.

If the refrigeration system is operated as a clockwise cycle (ORC machine), the expansion machine drives a generator that is connected to the vehicle's electrical energy supply and thus converts thermal energy into mechanical or electrical energy. This energy conversion is preferably regulated by means of the speed of the refrigerant pump located in the secondary circuit.

An additional heat exchanger between the primary circuit and the secondary circuit advantageously supports the cooling of the component of the energy supply or drive system to be cooled by the compression refrigerating machine at high outside temperatures.

The invention thus combines two core tasks: On the one hand, it serves to recuperate electrical energy from thermal energy, which is fed through the cooling circuit to a component of the energy supply or drive system that is to be cooled, for example a fuel cell. This task is mainly carried out at relatively low outside temperatures and works using the ORC process. The second task is to regulate the temperature inside the vehicle, which means that it works according to the principle of the cold vapor compression refrigeration process, particularly when the outside temperature is high.

The system partly uses existing and proven components, but combines them into a new type of system for vehicles, especially, but not exclusively, for rail vehicles.

A central part of the concept is the use of waste heat from at least one component of the vehicle to be cooled. At least one fuel cell and/or at least one traction motor and/or at least one power converter and/or at least one diesel engine can serve as such a component.

The disadvantages of the prior art are solved in that, in cold vapor compression refrigeration operation, the cooling circuit of the component to be cooled is decoupled from the primary circuit by means of a corresponding valve position, which leads the cooling capacity provided in this operating mode in the secondary circuit to the vehicle interior heat exchanger. The thus achieved possibility of dual use of the primary circuit for both modes of operation of the secondary circuit leads to a reduction in the outlay on plant engineering, in particular by saving on heat exchangers, which saves mass and costs.

The invention is explained in more detail below using exemplary embodiments and associated drawings.

• 1 das Verschaltungsschema der Kälteanlage,
• 2 die Verschaltung der Anlage bei kalten Außentemperaturen (ORC-Betrieb),
• 3 Verschaltung der Anlage bei warmen Außentemperaturen (Kompressionskälte-Betrieb).

Show it:

• 1 the wiring diagram of the refrigeration system,
• 2 the connection of the system at cold outside temperatures (ORC operation),
• 3 Connection of the system at warm outside temperatures (compression cooling operation).

For heat transport on the vehicle, a central heat transfer circuit (hereinafter "primary circuit", see 1 provided via the component (1) of the energy supply or drive system to be cooled, which is driven by a pump (P1). A water/glycol mixture, for example, can be used as the heat-transporting working medium in the primary circuit; other fluids are possible.
The refrigeration system itself has at least one inlet Z and at least one return R as interfaces to the primary circuit. Inside the system, the primary circuit is routed via at least one evaporator (2) and/or at least one supply air heat exchanger (3).

With an additional pump (P2) and a corresponding connection of the valves (V15) and (V16), the primary circuit inside the system can circulate as a closed circuit between the evaporator (2) and the supply air heat exchanger (3), which is particularly important for cooling the supply air is used in the air conditioning mode of the system.
The system also has a refrigerant circuit (hereinafter referred to as the secondary circuit), which, depending on the operating mode of the system, integrates different components and has different temperature and pressure levels. The refrigerants used have an evaporation pressure of more than 5 bar at the boiling temperature in ORC operation, such as propane, R513A, CO2.

For clear comprehensibility, the structure and function of the secondary circuit are therefore described in the two main operating modes:

Cold outside temperatures - ORC operation - See Figure 2

In this operating mode, the refrigerant is conveyed by the pump (P3) via a corresponding connection of (V25) and (V26) into the evaporator (2), where it is evaporated by the waste heat supplied from the primary circuit. It then passes through the valve (V21) into the expansion machine (T), which is driven by the expansion of the refrigerant and moves a generator (G) through a mechanical connection, which in turn generates electrical energy. Following the expansion, the refrigerant reaches the condenser (4) via (V23), where it is cooled by the outside air and condenses. The liquid refrigerant is sucked in by the pump (P3) via the refrigerant collector (S) and the valve (V24), which closes the circuit.

In the 2 Components shown with thin dashed lines Additional evaporator (6), compressor (K), pump (2), valve (V22), expansion valve (E) including the connecting lines leading to/from these are not required in this operating state.

In this operating mode (ORC operation), the evaporator (2) has an almost constant evaporation temperature of approx. 70°C. In the condenser (4), on the other hand, there is a condensation temperature that varies with the outside temperature between -10°C and 45°C. Using the example of refrigerant R513A, this results in an overpressure of approx. 20 bar in the evaporator (2) and approx. 2 to 12 bar in the condenser (4). The pressure levels of other refrigerants can be determined from calculations and reference tests.

Warm outside temperatures - cold vapor compression refrigeration operation - see figure 3

The second main operating mode is operated at a significantly different temperature and pressure level, which is made possible by the appropriately designed refrigerant collector S in the secondary circuit. The refrigerant absorbs heat in the evaporator (2), which is extracted from the supply air in the supply air heat exchanger (3) and via the heat transfer medium circuit, which is decoupled from the primary circuit by means of the valves (V14) and (V15) and driven by the pump (P2). to the evaporator (2). As a result, the refrigerant evaporates and is sucked in and compressed by the compressor (K) via the corresponding connection of V21. In this operating mode, too, the refrigerant is then fed via the valves (V22) and (V23) into the condenser (4), where it is cooled by the outside air and condenses. Via the refrigerant collector (S), the refrigerant is routed to the expansion valve (E) by means of the valve (V24) and then back to the evaporator (2), which closes the classic cold vapor compression refrigeration cycle. Optionally, the refrigerant pump (P3) can also be operated in this mode in order to feed part of the refrigerant via the valve (V25) to an additional evaporator (6), which supports the cooling of the drive components via the valves (V11) and (V12). and can therefore relieve the radiator (5) at high outside temperatures.
In the 3 Components shown as thin dashed lines: expansion machine (T), generator (G) including the connecting lines between the valves (V13) and (V14), (V15) and (V16), (V17) and (V18) and (V21) and (V22) are not flown through in this operating state.

In this operating mode (cold vapor compression refrigeration operation), the evaporator (2) has an almost constant evaporation temperature of approx. 5°C. In the condenser (4), on the other hand, there is a condensation temperature that varies with the outside temperature between 35°C and 70°C. Using the example of refrigerant R513A, this results in an overpressure of approx. 4 bar in the evaporator (2) and approx. 10 to 20 bar in the condenser (4). The pressure levels of other refrigerants can be determined from calculations and reference tests.

The solution according to the invention increases the overall efficiency of the vehicle by generating electrical energy in recuperation mode of the system and by using waste heat for heating, with weight and installation space being reduced to a minimum by the dual function of air conditioning and recuperation.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US 6880344 B2 [0002]
• JP 2006 [0003]
• JP 321389 A [0003]
• US 2019/0128146 A1 [0003]
• DE 102005032277 A1 [0003]

Claims (7)

Refrigeration system for vehicles, which has a primary circuit and a secondary circuit, characterized in that - a working medium flows through the primary circuit, - the primary circuit has an interface to a cooling circuit of at least one component (1) of the energy supply or drive system to be cooled, where this interface can be closed and bypassed via appropriate valves (V14, V15) - the primary circuit has a pump (P2) through which flow occurs when the valves (V14, V15) are connected accordingly, - the primary circuit has at least one heat exchanger (3) for temperature control of the vehicle interior, - the primary and secondary circuits are coupled via at least one heat exchanger (2), which serves as an evaporator in the secondary circuit, - a working medium with phase change flows through the secondary circuit, - the secondary circuit has an expansion machine (T), and via a compress sion machine (K), - the secondary circuit has at least one heat exchanger (4), which serves as a condenser for the refrigerant and is connected to both the expansion machine (T) and/or the compression machine (K), - the secondary circuit both after the cold steam -Compression refrigeration process, as well as the Organic Rankine (ORC) process can be operated. refrigeration system claim 1 , characterized in that the evaporator (2) and a condenser (4) are flowed through in the secondary circuit both in cold vapor compression refrigeration operation and in ORC operation. Refrigeration system according to one of the preceding claims, characterized in that the expansion machine (T) is designed as a turbine and is connected to the electrical energy supply of the vehicle via a generator (G). Refrigeration system according to one of the preceding claims, characterized in that a pump (P3), the speed of which can be used to regulate the recuperation of the system, is arranged in the secondary circuit. Refrigeration system according to one of the preceding claims, characterized in that an additional heat exchanger (3) supporting the cooling of the component of the energy supply or drive system to be cooled at high outside temperatures by the compression refrigeration process is arranged between the primary circuit and the secondary circuit. Refrigeration system according to one of the preceding claims, characterized in that the expansion machine (T) and compression machine (K) can also be replaced by a machine which can operate both as a compression machine and as an expansion machine. Refrigeration system according to one of Claims 1 until 6 , characterized in that the working medium in the primary circuit is a water / glycol mixture and / or the working medium in the secondary circuit is an organic refrigerant.

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