Refrigeration – Intermediate fluid container transferring heat to heat... – With indirect fluid pump or agitator
Reexamination Certificate
1999-12-23
2001-07-17
Doerrler, William (Department: 3744)
Refrigeration
Intermediate fluid container transferring heat to heat...
With indirect fluid pump or agitator
C062S430000, C062S434000
Reexamination Certificate
active
06260376
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates in general to an air conditioning installation for a motor vehicle, and in particular to an air conditioning installation for a motor vehicle with a cold reservoir, which can be charged with cold produced in an evaporator of a primary circuit.
An air conditioning installation with the characteristics of the preamble to claim
1
for a refrigerated goods vehicle is known from “Ki Klima-Kälte-Heizung”, June/1988 page 286, paragraph 3.1. The air conditioning installation includes a cold reservoir, which is produced in the form of a water tank which can equally well serve as an ice container. The cold reservoir can be charged from an evaporator of a primary circuit, the primary circuit, in the known way, forming a cooling circuit, which contains a compressor unit, a condenser and an expansion unit, in addition to the evaporator. The air conditioning installation of the generic type described here further includes a heat exchanger, which can deliver cold stored in the cold reservoir to the interior of the motor vehicle via a secondary circuit. With the air conditioning installation described here, this heat exchanger is charged with ice water from the reservoir by a circulating pump via a water circuit. The known air conditioning installation exhibits relatively sluggish response characteristics, because the entire volume of the water held in the reservoir has to be cooled, before the desired cooling can be made available via the heat exchanger. Moreover, the growth of the ice in the reservoir has to be controlled, the ice production and melting having to be kept in balance while the vehicle is in operation.
In view of the above-described drawbacks, so-called installations with a secondary evaporator have been developed. Such an air conditioning installation is likewise known from “Ki Klima-Kälte-Heizung”, June/
1988
page 286, paragraph 3.3. In this implementation, two cooling circuits are generally provided. The primary cooling circuit, in the usual way, includes a compressor unit, a condenser, an expansion unit and a primary evaporator, the primary evaporator serving, while the vehicle is in operation, to make the desired cooling power available for the refrigerated goods vehicle. The second cooling circuit is formed from the compressor unit and the condenser of the primary circuit, supplemented by a further expansion unit and a secondary evaporator, which is contained in an ice/water cold reservoir. The two cooling circuits are laid out in such a way that the primary evaporator and the secondary evaporator are connected in parallel. The known air conditioning installation thus allows the following modes of operation, while the vehicle is operating: pure air cooling while the vehicle is operating, via the primary evaporator; cooling by means of the primary and secondary evaporator while the vehicle is operating (charging of the ice tank); charging of the ice tank while the vehicle is operating without cooling by means of the primary evaporator. With the internal-combustion engine turned off, the ice tank can be discharged via the primary evaporator when standing still by circulating the cooling fluid by means of an electric pump, in order to make cold available to the primary evaporator.
Such installations with a secondary evaporator are therefore relatively complex in construction, so that their application to refrigerated goods vehicles is restricted, in particular by the high space demands, brought about among other things by the parallel connection of primary evaporator and secondary evaporator provided in the cold reservoir. Furthermore, it is not possible with the solutions known hitherto to remove cold from the cold reservoir while the vehicle is operating, which would be desirable, for example at low engine speeds. Consequently, prior solutions provide only an interim solution. Hence, there is a need for an improved air conditioning installation, which, like the known installations with a secondary evaporator, permits full use of the storage medium, since not required for circulation, and which is nevertheless structurally simple in implementation and can therefore be integrated with low space requirements even into a private car.
BRIEF SUMMARY OF THE INVENTION
The object of the present invention is thus to develop a generic air conditioning installation of the type set out in the introduction in such a way that, with a relatively simple implementation, a high operating efficiency and rapid response is achieved. A further object of the invention is to develop a known air conditioning installation in such a way that, even when the vehicle is operating, cooling power can be drawn from the cold reservoir. The space required for fitting the air conditioning installation should be small, so that it is even possible to fit it into a private car.
In accordance with the invention, the above objectives are achieved with a known air conditioning installation for a motor vehicle with a cold reservoir, which can be charged from an evaporator of a primary circuit, and with an optional heat exchanger which can deliver cold stored in the cold reservoir via a secondary circuit to the interior of the vehicle, in that the secondary circuit contains at least one further heat exchanger, which is in a heat-exchanging relationship with the evaporator of the primary circuit and forms an evaporator/heat exchanger unit. Because the further heat exchanger is in a heat-exchanging relationship with the evaporator of the primary circuit, satisfactory response characteristics are guaranteed, with it being possible, depending on the operating conditions, for cold to be charged into the cold reservoir or removed from it. The evaporator/heat exchanger unit thus forms, in combination, a cold source for the vehicle air conditioning and a decoupled interface to the secondary circuit for storing surplus cold power or for drawing cold power from the reservoir, for example when the internal-combustion engine is turning at low speeds. To you [sic] invention makes it possible, in a simple way, to extend an existing direct evaporator air conditioning installation around the secondary circuit, and, by means of the cold reservoir, allows simple but effective air conditioning while stationary.
Advantageously, the further heat exchanger is in a heat-exchanging relationship with the evaporator of the primary circuit as well as with the cold reservoir. Because the further heat exchanger is in a heat-exchanging relationship with the evaporator of the primary circuit, satisfactory response characteristics are guaranteed. Since the further heat exchanger is additionally also in a heat-exchanging relationship with the cold reservoir, cold from the cold reservoir can be made use of with the engine stopped as well as at low engine speeds. Consequently, this solution makes available a structurally simple coupling between three temperature levels and/or cold sources, so that an overall engineering design with minimal space requirements is achieved, which it is even possible to install in a private car.
As regards the individual heating or cooling transfers, it should be mentioned that, depending on prevailing conditions and/or operating states, a predominant situation could exist. For example, it could be envisaged that the evaporator of the primary circuit be in a prioritized or exclusive heat-exchanging relationship with the further heat exchanger of the secondary circuit, such that the charging of the cold reservoir thus takes place with the further heat exchanger of the secondary circuit connected intermediately. It is therefore preferred for the evaporator of the primary circuit to be in a heat-exchanging relationship with the cold reservoir, essentially with the further heat exchanger of the secondary circuit connected intermediately.
In a preferred embodiment, the evaporator is essentially contained in the further heat exchanger of the secondary circuit, with the further heat exchanger of the secondary circuit essentially being able to be contained in
Khelifa Noureddine
Riehl Horst
Doerrler William
Morgan & Finnegan , LLP
Shulman Mark
Valeo Klimasysteme GmbH
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