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Nuovi refrigeranti ad elevato glide - S. Filippini - LU-VE

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Convegno Europeo
IL PASSAGGIO AI REFRIGERANTI ALTERNATIVI:
IMPATTO SU IMPIANTI NUOVI ED ESISTENTI
Le Ultime Tecnologie nel Condizionamento e nella Refrigerazione; Sistemi, Attrezzatura, Componenti, Formazione e Certificazione; il Phase Down
15 marzo 2018 | 14.00 - 18.30
Mostra Convegno Expocomfort
Centro Congressi Stella Polare: Sala Sagittarius
Organizzato da ATF - Associazione Tecnici del Freddo

Published in: Environment
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Nuovi refrigeranti ad elevato glide - S. Filippini - LU-VE

  1. 1. Stefano Filippini, MCE 2018 Nuovi refrigeranti ad elevato glide: impatto sugli scambiatori di calore in nuovi e vecchi impianti High glide refrigerants: impact on heat exchangers in new and old systems
  2. 2. F-Gas 2014 F-Gas Regulation • Limit the total amount of F-gases that can be sold in the EU from 2015 onwards and phasing them down in steps to one-fifth of 2014 sales in 2030. • Banning the use of F-gases in many new types of equipment • Preventing emissions of F-gases from existing equipment by requiring checks, proper servicing and recovery of the gases at the end of the equipment's life.
  3. 3. Possibilities? •Low GWP ref.HFC, HFO •CO2 •propane Natural refrigerant
  4. 4. Your partner in COOP WETTINGEN - Zurig - Switzerland Gas cooler CO2 SHVDT 696 CO2 (2004) LU-VE advantages on CO2 • High performance unit • Reliable performance and know how (laboratory testing plant) • Experience in transcritical: installations running for more than 10 years CO2
  5. 5. Refrigerant ref. PURE (1-comp.) MIX AZEOTROPIC constant boiling point QUASI-AZEOTROPIC ZEOTROPIC different boiling pointsClassification R4__ → zeotropic mix. R5__ → azeotropic mix. refrigerant R134a R404A R507A R407C, R407F, R448A, R449A
  6. 6. ZEOTROPIC MIX. • The new refrigerant with lower GWP for refrigeration purpose (i.e. R448A, R448A with GWP = 1250 about half compared to R404A) have all high glide (about 6K) p = cost refrigerant GWP Glide
  7. 7. Mixture and glide • component with the lowest boiling point evaporates earlier • the second component evaporates at higher temperature; i.e. the mean evaporating temperature will rise steadily over the two-phase range • Dewpoint temperature: temperature corresponding to the evaporation of the last liquid droplet (evaporator) or to the condensation of the first liquid droplet (condenser) • Bubble point temperature: temperature corresponding to the condensation of the last liquid droplet (condenser) or to the evaporation of the first liquid droplet glide = Tdew point(p) – Tbubble point(p) Glide p h DEW POINT isobar isotherm BUBBLE POINT DT = glide
  8. 8. Glide Heat exchangers - DEW POINT calculation The temperature glide of zeotropic refrigerant mixtures • smaller temperature differences at the condenser → performance decreases • greater temperature differences at the evaporator → performance increases T h COND LOSS EVAP GAIN pure ref. high glide mix
  9. 9. Glide Heat exchangers – MID POINT calculation • Using mid point calculation method, in condenser and evaporator gain and loss are almost balanced T h mean temperature LOSS GAIN
  10. 10. Certification EUROVENT  Eurovent is defining some coefficients allowing to predict the performances of heat exchangers operating with new refrigerants with high glide  The new coefficients will help designers and installers to predict properly the heat exchangers performances, allowing an easy performance calculation
  11. 11. Certification According to RS 7/C/008 – 2018 “EUROVENT RATING STANDARD for DX AIR COOLERS, AIR COOLED CONDENSERS, DRY COOLERS” refrigerant correction factor for capacity are defined: Nominal capacity = C3 * Nominal capacity_R404A Table 1: EUROVENT Refrigerant correction factor (C3) Refrigerant Dx air coolers Air cooled condenser Glide @40°C SC1 SC2 SC3 SC4 DT1=15K or DT1=10K information only R404A 1 1 1 1 1 0,5 R134a 0,93 0,91 0,85 - 0,96 0,00 R507A 0,97 0,97 0,97 0,97 1 0,00 R407A 1,19 1,24 1,28 1,32 0,89 4,50 R407C 1,21 1,26 1,31 1,36 0,87 5,06 R407F 1,19 1,24 1,29 1,35 0,89 - R448A 1,23 1,26 1,28 1,31 0,89 4,82 R449A 1,21 1,23 1,24 1,26 0,89 4,65 R450A 0,92 0,91 0,84 - 0,93 0,63 R452A 1,10 1,12 1,13 1,15 0,93 3,43 R513A 0,91 0,91 0,85 - 0,95 0,17  coefficients are defined for dew point calculation  mid point …work in progress
  12. 12. MINICHANNEL® - Air cooled condensers Tube Ø5 mm 160% Standard market 100% LU-VE Standard 50% Minichannel® Condenser internal volume Refrigerant charge Reduced refrigerant charge
  13. 13. Example ؽ’’ Ø3/8’’ Ø5mm Example: • Capacity: 67kW (27 HP) • Sound power @ 10m: max 48 Internal volume 21 dm3 6,4 kg of refrigerant -68% kg of refrigerant compared to solution with 3/8’’ diameter 3x ø500 - 2 rowsInternal volume 18 dm3 5,4 kg of refrigerant 3x ø500 - 3 rows 1x ø800 - 3 rows Internal volume 5,6 dm3 1,7 kg of refrigerant
  14. 14. Example • T. room: 2°C • DT1=8K • Capacity: 7,5 kW (3HP) Power consumption: 306 W Internal volume: 4,10 dm3 Air flow: 5250 m3/h Air throw: 25 m T out evap: -1°C Power consumption: 204 W Internal volume: 2,80 dm3 Air flow: 3300 m3/h Air throw: 20 m T out evap: -2,5°C R404A today R449A tomorrow Some capacity with different units T.evapmean=-6°C DTmean= 8K T.evapmean= ~ -7,5°C DTmean= 9,5K
  15. 15. Example • T. room: 2°C • T.evapmean=-6°C • Capacity: 7,5 kW (3HP) Power consumption: 306 W Internal volume: 4,10 dm3 Air flow: 5250 m3/h Air throw: 25 m T out evap: -1°C R404A today R449A tomorrow DTmean= 8KDTmean= 8K
  16. 16. THANK YOU!

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