CN104610919B - Suitable for the environmental protection refrigerant of cryogenic refrigeration systems - Google Patents

Abstract

The invention discloses a kind of environmental protection refrigerant suitable for cryogenic refrigeration systems.The composition and mass percent of refrigerant match：Difluoromethane 50%；Dimethyl ether 3%；1,1,1,2 HFC-134as 47%.It is 25~30 DEG C in condensation temperature, is 1.020 (40HZ) with respect to COP, 1.035 (50Hz), energy saving of system rate is more than 5% during 25 DEG C or so of evaporating temperature.Substitute R404A high-efficiency environment friendly refrigerant, have the characteristics that ODP is zero, GWP relatively low (946), filling quantity smaller (70% or so), thermodynamic property is excellent and market availability is good, can directly it fill in the freezing and refrigerating system using R404A refrigerants originally, excessive part replacement need not be done, does not need re-injection lubricating oil more.And R404A has better performance coefficient and energy-saving effect compared with relatively low evaporating temperature operating mode in higher condensation temperature.

Description

Suitable for the environmental protection refrigerant of cryogenic refrigeration systems

Technical field

The invention belongs to the refrigerant in heat pump or refrigeration, air-conditioning system, the environmental protection for the cryogenic refrigeration systems that are particularly suitable for use in Refrigerant.

Background technology

《The Kyoto Protocol》With《Montreal Protocol》Frame foundation on, national governments and scientific research institution and row Industry enterprise has carried out substantial amounts of work from policy making, technical research to industrial practice, and European fluoro-gas regulation is newest to be carried Case proposes that the freezing and refrigeration cabinet of retail business, from 2015, the GWP value of refrigerant must not exceed 2150, more next in the world More focus on from Ozonosphere protection and suppress the broad aspect overall merit refrigerant environmental-protecting performance of global warming two, it is seen that reduce GWP value it is important.By the end of the end of the year 2012, China shares about 9.85 ten thousand, freezer, increases by 11.3% on a year-on-year basis, wherein newly-increased freezer About 2,600,000 tons of capacity.Announced according to National Development and Reform Commission《Product Cold Chain Logistics development plan》, China planned by 2015 National freezer total capacity is increased to 18,800,000 tons, faces the continuous growth of freezer quantity, the demand of refrigerant and production also day It is cumulative more, accelerate the superseded process of high GWP value refrigerant significant.

The most widely used R404A of Refrigeration industry at present, belong to the refrigeration of the fluoro-gas regulation limitation in Europe Agent, the research of its substitute technology are particularly urgent.R404A is a kind of ternary near-azeotrope mixture refrigerant, is preferably replacing for R502 For refrigerant.But R404A is remained certain the defects of, although ODP values are 0, but still has higher GWP (3850) value, It is incompatible with the environmental requirement of current control greenhouse gas emission.The present invention proposes that a kind of non-azeotrope ternary mixed refrigerant can Suitable for cryogenic refrigeration systems, the substitute as R404A.

The content of the invention

It is an object of the invention to provide a kind of environmental protection refrigerant suitable for cryogenic refrigeration systems；Substitute cryogenic freezing refrigeration System R404A mixed refrigerant, make its environmental characteristics and cycle performance optimal.

The energy-saving and environmental-friendly refrigeration agent suitable for cryogenic freezing refrigerating system of the present invention, by R-32 (difluoromethane), DME (dimethyl ether) and R-134a (1,1,1,2- HFC-134as) are formed.

As shown in Table 1, it is respectively provided with higher critical-temperature and critical pressure to the basic physical property of three kinds of constituent elements, can To be used under worst hot case, the ODP of three kinds of constituent elements is 0, GWP relatively low, especially DME, and its GWP has close to 0 Higher refrigerating effect per unit swept volume.Although three kinds of constituent elements exist《Moderate and high temperature heat working medium》Had been found in patent in being applicable to High temperature heat pump system, and there is good effect, but the operating mode of its HTHP can not entered to freezing and refrigerating system Cryogenic refrigeration systems are directly applied under the premise of the excessive change of row, this patent is to mix refrigerant under three kinds of constituent element different ratios Theory analysis is carried out, draws physical parameter and the extremely similar refrigerants of R404A, and the best composition with of a relatively high COP Ratio, the direct irrigation of novel refrigerant can be achieved.Novel energy-saving environment-friendly refrigerant is characterized in the specific matter of three constituent element materials Amount percentage, which matches, is：

Difluoromethane 50%,

Dimethyl ether 3%,

1,1,1,2- HFC-134as 47%.

Each constituent element basic parameter of the mixed refrigerant of table 1

Tb：Normal boiling point, Tc：Critical-temperature, Pc：Critical pressure

The preparation method of environmental protection refrigerant of the present invention is the quality proportioning Low Temperature Liquid for specifying three constituent element materials by it Body (gas at normal temperature) carries out physical mixed.

Physical parameter about mixed refrigerant and R404A is as shown in table 2：Both physical parameters are basically identical, R404A is a kind of near azeotropic mixed refrigerant, and at normal atmospheric pressure, the temperature glide of mixed refrigerant is 7.56 DEG C, Mix refrigerant as non-azeotrope has reduction system pressure ratio, increases refrigerating capacity, improves the advantages that circulating thermodynamic perfect degree.Newly Type mix refrigerant molecular weight is low compared with R404A.Its GWP value is 946, about the 24.6% of R404A, therefore greenhouse effects is potential Ability is relatively small.

Although DME has inflammable and explosive characteristic, the content in mixed refrigerant is less, and R-134a is just There is certain anti-flammability, therefore greatly reduce the combustibility of mixed refrigerant, DME is that one kind has special odor in addition Gas, can be as a kind of method whether checking system is revealed.

The R404A of table 2 is compared with mixed refrigerant basic physical properties parameter

Parameter	R404A	Mixed refrigerant
			Molecular weight/(kg/kmol)	97.60	67.26
Critical-temperature/DEG C	72.14	89.36
			Critical pressure/kPa	3.375	5.254
Critical density/(kg/m3)	488.5	430.65
			Bubble point temperature (DEG C)	-46.57	-45.68
Dew-point temperature (DEG C)	-45.79	-38.12
			Temperature glide (DEG C)	0.78	7.56
ODP value/1	0	0
			GWP value/1	3850	946
It is flammable	It is non-ignitable	Weak combustibility

Note：Saturation temperature when bubble point temperature and dew-point temperature are standard atmospheric pressure 101kPa in table

Brief description of the drawings

Fig. 1 novel refrigerants are compared with R404A refrigerating effect per unit swept volumes；

Fig. 2 novel refrigerants are compared with R404A COP；

Fig. 3 R404A delivery temperatures；

Fig. 4 novel refrigerant delivery temperatures.

Embodiment

Embodiment：It is according to mass percent according to three constituent element materials

Difluoromethane 50%,

Dimethyl ether 3%,

1,1,1,2- HFC-134as 47%.

Matched, carrying out physical mixed with low temperature liquid or the gaseous state of normal temperature prepares refrigerant of the invention.

Below by under different operating modes mixed refrigerant substitute R404A and carry out theoretical analysis and test to verify Its advantage.The design conditions of freezing and refrigerating system are taken as：Condensation temperature=10,15,20,25,30,35,40,45,50 DEG C； Evaporating temperature=0, -5, -10, -15, -20, -25,30 DEG C；The degree of superheat=25 DEG C (effectively 5 DEG C of overheat, invalid 20 DEG C of overheat)；Cross Cold=5 DEG C of degree；Compressor adiabatic efficiency 0.8, volumetric efficiency 0.95.

Mixed refrigerant and R404A refrigeration cycle performance parameter under freezing and refrigerating system difference operating mode are entered respectively Row theoretical calculation, including refrigerating effect per unit swept volume, compressor exhaust temperature and condensing pressure etc., and to the relative performance of the two Parameter has carried out comparing analysis, as shown in accompanying drawing 1-4.

As a result show：Although the application of mixed refrigerant causes the delivery temperature of compressor generally to improve, Its refrigerating effect per unit swept volume and coefficient of performance of refrigerating increase compared with R404A under the higher operating mode of condensation temperature, and along with steaming It is bigger with respect to COP for the reduction of hair temperature, illustrates that new refrigerant has energy-efficient advantage under certain operating mode.In view of the two Condensing pressure it is basically identical, this demonstrates the feasibility using direct filling type alternative solution from system pressure angle.

It is zero that mixed refrigerant, which has ODP, GWP relatively low (946), charging amount few (70% or so), thermodynamic property The features such as excellent and market availability is good, can directly it fill in the freezing and refrigeration system for using R404A refrigerants originally In system, it is not necessary to do excessive part replacement, do not need re-injection lubricating oil more.This patent is for strengthening freezing and refrigeration system of China The competitiveness of system refrigerant special in the international market, accelerates the superseded process of high GWP refrigerant significant.

Higher condensation temperature (>35 DEG C), relatively low evaporating temperature (<- 30 DEG C) under operating mode, mixed refrigerant phase There is of a relatively high refrigerating effect per unit swept volume and COP to R404A, be a kind of energy-efficient refrigerant.

For preferred forms, actual working characteristics are tested on freezing and refrigeration testing stand.Respectively in compressor set Under 40Hz and 50Hz winter operation operating modes, the freezing and refrigerating system based on refrigerant R404A and mixed refrigerant is entered The experimental study of refrigeration performance is gone.Cooling condition performance test results show：The freezing and refrigerating system application present invention's is new The agent of type energy-saving and environmental-friendly refrigeration can obtain the higher coefficient of performance, relatively low compressor high-low pressure ratio, less energy consumption.In condensation temperature Spend for 25~30 DEG C, be 1.020 (40HZ) with respect to COP during -25 DEG C or so of evaporating temperature, 1.035 (50Hz), the total body segment of system Energy rate is more than 5%.

R404A high-efficiency environment friendly refrigerant is substituted, to have ODP be zero, smaller (70% is left for GWP relatively low (946), filling quantity It is right), thermodynamic property it is excellent and the features such as market availability is good, can directly fill and be freezed in originally using R404A In the freezing and refrigerating system of agent, it is not necessary to do excessive part replacement, do not need re-injection lubricating oil more.And in higher condensation Temperature R404A compared with relatively low evaporating temperature operating mode has better performance coefficient and energy-saving effect.The present invention has non- Often good application effect and development potentiality.

Claims (1)

1. A kind of 1. environmental protection refrigerant suitable for cryogenic refrigeration systems；It is characterized in that component and mass percent are：

   Difluoromethane 50%,

   Dimethyl ether 3%,

   1,1,1,2- HFC-134as 47%.