ENVIRONMENTAL IMPACT OF R22 RETROFITING. Liviu DRUGHEAN (*), Anica ILIE (*), Alina GIRIP (*), Daniela TEODORESCU (*)

Transcription

1 ENVIRONMENTAL IMPACT OF R22 RETROFITING Liviu DRUGHEAN (*), Anica ILIE (*), Alina GIRIP (*), Daniela TEODORESCU (*) 1

2 1. INTRODUCTION The Montreal and Kyoto Protocol have introduced a series of the restrictions regarding usage of refrigerating agents with negative environmental impact. The European Union have established a program for progressive replacement of Ozone Depleting Substances (ODS) according to CE 2037/2000 and EU Regulation(1005/2009/EC), regarding the production and consumption of this substances. There are two unanimously accepted deadlines which have become necessary, such as: January 1, 2010 after this date, usage of Hydro-cloro-fluorocarbons HCFC (virgin substances) for refrigeration systems is prohibited; January 1, after this date the Hydro-chloro-fluorocarbons HCFC, will not be using in the refrigeration systems at all (also including recovered substances). 2

3 The countries which are non Article no. 5 of the MONTREAL PROTOCOL may still use hydro-chloro-fluorocarbons (HCFC) till January Those countries may use virgin substances until 2020 (2007 IOR Guidance Notes 15). According to the large number of refrigeration systems which are still running and their life cycle about years, by the end of 2014 many of these systems are still at half of their operating period. Therefore, efforts are being made by specialists to identify possible R22 replacement refrigerants without changing the equipment from plants. In this context, replacement solution could be viable and attractive for the owners of such systems. In addition, manufacturers must provide the users with not expensive and available replacement methodology to avoid the marketing of R22,, l a b e l e d f a l s e " a n d s a l e,, m a s q u e ". 3

4 What are the options? Option Advantages Disadvantages Replace whole plant Modify plant to use a new refrigerant New plant can be designed to have best energy efficiency. New plant can meet your current and future cooling requirements and use the latest technology. New plant will have 20 to 30 year life. You can chose an alternative refrigerant such as ammonia, HCs or CO2. Fairly quick implementation. Probably much lower capital cost than plant replacement. Most expensive option in terms of first cost. Longest implementation time. Efficiency might get worse. Cooling capacity might fall Not applicable to all plant designs. Some risks of reliability problems. Plant life not being extended.

5 Choosing refrigerant for certain refrigeration equipment, even if it s substitute, is based on technical and economic analysis through the following criteria: thermophysical and thermodynamic (physical and transport properties of refrigerant - table1); technological compatibility (lubricating oil and the behavior towards the metallic or non-metallic materials in the refrigeration system)-table 2; safety and environmental requirements (toxicity and flammability), Ozone Depleting Potential (ODP), Global Warming Potential (GWP), Total Equivalent Warming Impact (TEWI) - table2; economic, refers to the price and availability of the refrigerant on the market. 5

6 Table 1. Physical and thermodynamic properties Ref. Type / substance Boiling point p=1 bar [ C] T k [ C] P k [bar] T Glide [K] Mass participation of components [%] R22 Pure substance R134a Pure substance R290 Pure substance R600a Pure substance R152a Pure substance R507 Azeotropic %R % R134a blend 7 R407C Zeotropic blend % R134a - 25% R125-23% R32 9 R404A Quasi zeotropic blend % R143a - 44% R124 4% R134a R410A Quasi zeotropic <0.2 50% R32-50% R125 blend 6 R417A Zeotropic blend % R125-50% R1234a - 3,4% R600 R422A Zeotropic blend % R % R134a - 3.4% R600a R424A Zeotropic blend % R125-47% R134a 0.9% R600a 1%R % isooptane R427A Zeotropic blend % R134a - 25% R125-15% R32-10% R143a R428A Quasi zeotropic blend % R125-20% R134a 1.9% R600a 0.6% R290 6

7 Ref. Table 2. Lubricant and refrigerant compatibility Mass participation of component substances [%] Lubricant Oil Safety classification ** ODP [-] GWP* [-] R22 - Mineral A R134a - POE A R290 - Mineral A3 0 3 R600a - Mineral A3 0 3 R152a - POE A R507 50%R % R134a POE A R407C 52% R134a - 25% R125-23% R32 POE A R404A 52% R143a - 44% R124-4% R134a POE A R410A 50% R32-50% R125 POE A R417A 46.6% R125-50% R1234a - 3,4% R600 Mineral A R422A 85.1% R % R134a - 3.4% R600a Mineral A R424A 50.5% R125-47% R134a 0.9% R600a 1%R % isooptane Mineral A R427A 50% R134a - 25% R125-15% R32-10% R143a POE A R428A 77.5% R125-20% R134a 1.9% R600a 0.6% R290 Mineral A

8 2. OBJECTIVES Comparative analysis of a number of potential replacement refrigerant for R22 used for different refrigeration plants from an environmental impact perspective (the TEWI coefficient). In order to assess environmental impact of these potential subsistents, the f o l l o w i n g r e f r i g e r a n t s h a v e been c o n s i d e r e d : substitutes currently used in existing systems: R134a, R290, R600a, R152a, R507, R407C, R404A, R410A; new substitutes, recommended for new systems: R417A; R422A; R424A; R427A, R428A. 8

9 Comparative analysis have been made for 3 types of refrigeration plants which operate with different refrigerants from the view of TEWI factor perspective, as follows: air conditioning-split unit, with a cooling capacity of 10,55 kw (t in = 25 C, t amb = 35 C); air cooled chiller, with a cooling capacity of 11.3 kw (t cooled water = 7 /12 C, t amb = 35 C); air cooled refrigeration system with direct and indirect evaporation for cold storage (medium temperature space t int = 0 C and low temperature space t int = -20 C, t amb =35 C), cooling capacity 11.3kW. 9

10 3. ENVIRONMENTAL IMPACT OF REFRIGERANTS TEWI = (GWP*l*n) + GWP*m*[1- REC ] + (n*e* ) Total Equivalent Warming Impact TEWI sums up the effect of three components, respectively: 1. the impact of refrigeration agent release to the air during recovery, while the unit is operational; 2. the impact of refrigeration agent release to the air during recovery, when the operational limit of the unit is reached; 3. the impact due to CO 2 emissions when the installation driving energy is produced (an indirect effect). The first two components represent the direct effect, mainly due to the refrigerant and the last component representing the indirect effect. TEWI factor was calculated using this equation. 10

11 4. CALCULATION HYPOTHESES GWP (2012 Bitzer Refrigerant Report 17); m refrigerant charge [kg]; l leakage rate(3 8%); n system operating life (n = 10 year); E energy consumption per year [kwh]; P k compressor power consumption [kw]; n hour annual number of compressor operating hours (h/an), n hour = 610 h/an; REC recovery/recycling factor = %; -indirect emission factor = for Romania, (2012 Guidelines). superheating of refrigerant about 5K and the isentropic efficiency of the compressor about 0.8; different evaporation temperatures; total electrical power for operation (compressor, ventilators - evaporator and condenser -, pumps (for indirect evaporation system). 11

12 5. RESULTS Variation of the TEWI is illustrated in figures 1 6 for each type of the analysis systems Figure 1. TEWI for residential air conditioning system direct expansion system 12

13 Figure 2. TEWI for air conditioning chiller 13

14 Figure 3. TEWI for medium temperature system direct expansion system 14

15 Figure 5. TEWI for low temperature system direct expansion system 15

16 Figure 4. TEWI for medium temperature system indirect expansion system 16

17 Figure 6. TEWI for low temperature system indirect expansion system 17

18 6. DISCUSSIONS At the same operating conditions the mass flow rate have different values depending on refrigerant using. At the same time, it can be noted that once evaporation temperature decreases, the mass flow rate for that refrigerant decreasing. This decrease is due to its specific increase in volume. When the evaporation temperature decreases the total input power is slightly decreased for indirect evaporation cycle then for direct evaporation. This fact may be explained by the fact that refrigerant s mass flow rate decreases much more while the specific mechanical work for compressor increases. If we taken into account the TEWI coefficient can be grouped into 3 categories (according to R22 TEWI factor): Approx. 2% deviation R417A, R407C, R427A, R424A; Approx % deviation R134a, R410A, R290, R600a and R152a; Approx % deviation: R507, R404A, R428A and R422A. For substituents considered at points b and c do not recommend their use because the plant will operate with a significant decrease of the cooling capacity. They may be used if some of the parts of the system will be redesign. The natural refrigerants (R290 and R600a) and HFC (R152a) correspond to the safety group A3-A2. In this case there is some limitation for using them in some applications. 18

19 7. CONCLUSIONS TEWI factor values calculated for the 3 types of equipment (residential air conditioning system, air cooled systems with direct and indirect evaporation for cold storage (for medium temperature t int = 0 C and low temperature t int = -20 C, ambient temperature t ext = 35 C) are lower for indirect evaporation compared to the corresponding direct evaporation. Maximum deviation of 20% is obtaining for medium temperature system. The current study demonstrates if the evaporation temperature decreasing with 15K for medium temperature system the TEWI factor decreasing by approx %. Direct effect of TEWI coefficient is within a range of % for most of the refrigerating plants. The minimum values are for R290, R600a and R152a where direct effectis about 2%. 19

20 Refrigerant conversion options 1. Conversion using a pure HFC refrigerant. - R134a - increasing compressor capacity by about 30%; different lubricating oil; non-metallic components must be changed (seals) which will represent a large financial investment. 2. Conversion using an HFC blend. - R407C, R404A and R507 - it will be necessary to convert to a new type of oil (POE), necessary to change some seal materials 3. Conversion using an HFC Service Blend. - R417A - blends which can be used directly by removing the old substance some simple adjustments must be done to certain controls before running again the system. 2-4 December 2015, Belgrade, Serbia 20

21 Cooling capacity of difrents R vs R22 [%] Theoretical study regarding the thermal performances of potential substitutes for Freon R22 (Drughean L. & al. 2013) Based on the graphics for EER/COP it can be observed that agents R422A, R424A, R417A and R428 which evolve in refrigerating installations as well as in heating pumps installations favor a result of higher performance coefficients in rapport with the substitutes of the R404A, R407C or R410A types. In consequence we will be using these potential substitutes to study the thermal performance in refrigerating installations when changing the agent R22. Fig. 4. The refrigerating power s variation when changing the agent for different condensing temperature R417 R422A R424A R428 Condensing Temperature [ C] Cooling capacities variation for differents refrigerants in conection with R for different condensing temperature 2-4 December 2015, Belgrade, Serbia

22 Electrical power of compressor,[kw] Experimental Results and Conclusions 0,31 0,29 0,27 (Drughean L. & Co ) 0,25 0,23 0,21 0,19 0,17 R22 R417 0, ,2 19,4 19,6 19,8 20 Condenser temperature,[ C] 8,6 8,4 8,2 EER R417 EER R22 EER, [-] 8 7,8 7,6 7,4 7,2 1,705 1,504 1,518 1,453 1,457 Φ0, [kw]

23 Last but not the list! WE must take into consideration moving to Natural Refrigerants!. and the F Gas Regulation. - R717 - if there is a large plant, advantages in highly efficient plant, minimise the emissions of greenhouse gases, maybe an expensive option because of the safety precautions required. -R744 - successfully used (or together with R717) a lot in the last period on supermarkets, food processing or cold storage applications. 23

24 Multumesc pentru atentie! Thank you! Хвала на пажњи! 24