Method for operating a subcritically and transcritically...

Refrigeration – Processes – Compressing – condensing and evaporating

Reexamination Certificate

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

C062S498000

Reexamination Certificate

active

06298674

ABSTRACT:

The invention relates to a method for operating a subcritically and transcritically operated vehicle air conditioner.
BACKGROUND
DE 4432272 C2 describes a method for operating a refrigerating apparatus for air conditioning vehicles. The vapour compression circuit has at least in each case one compressor, one gas cooler, one throttling means and one evaporator. The refrigerating capacity is regulated by a compressor which controls the refrigerant mass flow. The refrigeration efficiency is a function of high pressure in the case of supercritical heat output at the gas cooler. The desired high pressure is set by means of an expansion valve.
EP 0 424 474 B1 describes a method for transcritical and supercritical operation of a vapour compression circuit. The air-conditioning circuit has a compressor, a cooler, throttling means and an evaporator. The refrigeration efficiency is a function of high pressure in the case of supercritical heat output at the cooler. The high pressure is regulated by variation of the refrigerant quantity on the high-pressure side of the circuit.
With this type of operation of a vehicle air conditioner, it is disadvantageous that upon starting up the vehicle air conditioner, the refrigerant mass flow and the high pressure do not immediately rise to the desired value. This is to be ascribed, for example, to the fact that additional pressure drops are produced in the system, and the refrigerant mass distribution in the overall system does riot correspond to the desired distribution. It is particularly disadvantageous when determining the optimum high pressure to use the refrigerant temperature at the gas cooler outlet, since this is itself a function of the high pressure, and thus subjected to incessant fluctuations.
The object of the invention is to improve a vehicle air conditioner so as to permit efficient starting up of the conditioner and efficient and reliable operation of the conditioner.
SUMMARY
A method according to the invention is for operating a subcritically and transcritically operated vehicle air conditioner having a vapour compression circuit in which in which a compressor, a gas cooler, an expansion valve and an evaporator are connected in series and form an integral closed cycle. On the high-pressure side of the vapour compression circuit, for the purpose of offering refrigerating capacity, a pressure is produced which is supercritical with reference to the critical pressure of the refrigerant circulating in the circuit, and a subcritical pressure is reached simultaneously on the low-pressure side of the circuit. Thermal energy is fed via the evaporator to the refrigerant cooled down on the low-pressure side with the refrigerant mass flow being regulated by the compressor and the desired high pressure being set by means of an expansion valve. During the starting operation of the vehicle air conditioner, the refrigerant mass flow is set directly to a required value and the refrigerant pressure is set in accordance with at least one prescribed parameter, and the air conditioner is regulated upon the overshooting of safety pressure limits P
1
-P
4
, the regulation depending upon which safety pressure limits are overshot.


REFERENCES:
patent: 5497631 (1996-03-01), Lorentzen et al.
patent: 5685160 (1997-11-01), Abersfelder et al.
patent: 5901560 (1999-05-01), Heile et al.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Method for operating a subcritically and transcritically... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method for operating a subcritically and transcritically..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for operating a subcritically and transcritically... will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-2588200

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.