Working condition concentration control system of mixed working medium throttling refrigerating machine and working condition concentration control method

Abstract

The invention discloses a working condition concentration control system of a mixed working medium throttling refrigerating machine and a working condition concentration control method. The working condition concentration control system comprises a compressor unit, a condensing cooler unit, a back heating heat exchanger unit, a throttling unit, an evaporator unit, a controllable path working medium circulation concentration and flow rate regulating unit and a control unit. The input parameters are the compressor gas suction pressure and / or exhaust pressure values of a refrigerating machine system, the inlet temperature value of a back heating heat exchanger, the outlet temperature value of the back heating heat exchanger, an inlet temperature value of the throttling unit, the outlet temperature value of the throttling unit and the outlet temperature value of an evaporator, and output parameters are instructions for controlling an executing unit to generate corresponding actions. The system and the method correspond to different operation working conditions and capability regulation requirements of the mixed working medium throttling refrigerating machine system, and according to the comparison between the preset value and the input parameters, the working medium circulation concentration of the refrigerating machine system is controlled and regulated through the controllable path working medium circulation concentration and flow rate regulating unit, so the system and the method can meet the operation requirements of different working conditions, and in addition, higher operation efficiency can be maintained.

Description

technical field [0001] The invention relates to the subject field of engineering thermophysics and energy utilization, in particular to a concentration control system and a method for working condition concentration of a mixed working medium throttling refrigerator. Background technique [0002] Using traditional vapor compression refrigeration technology, the minimum effective refrigeration temperature that can be achieved by a single-stage cycle is around -40°C. If you want to achieve a lower refrigeration temperature, you need to use multi-stage compression or multi-stage cascade cycle. In the existing technology, two-stage compression can achieve a refrigeration temperature of about -60°C, and a two-stage cascade cycle can achieve a refrigeration temperature of about -80°C, but to achieve a refrigeration temperature of -100°C or even lower, it is necessary to Take more than three levels of cascade loops. Therefore, as the demand temperature decreases, the refrigeration ...

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Problems solved by technology

[0003] However, due to the characteristics of the mixed working medium used in the mixed working medium throttling refrigeration technology, if the corresponding technical means are not used to control it, there will be some defects as follows: (1) The multi-component mixed working medium cryogenic refrigeration system, due to the use of Strong non-azeotropic working fluid, the working fluid in the condenser is basically exothermic in the gas phase, the outlet of the condenser has a certain dryness, and will not be overcooled

In this way, the efficiency of the system is ensured by adjusting the appropriate concentration. Generally speaking, the power of the system does not change much after adjusting the concentration, but the efficiency can be improved; instead of adjusting the concentration, just increasing the flow to increase the power may be due to changes in the concentration. , the refrigeration efficiency cannot be improved. Obviously, this method is not effective compared with adjusting the concentration and is not energy-saving

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