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

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. 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. Possibilities?
•Low GWP ref.HFC, HFO
•CO2
•propane
Natural
refrigerant

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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. THANK YOU!