background image

RECIPROCATING COMPRESSORS

Maneurop®  NTZ  compressors  have 
been  designed  and  qualified  for  sta-
tionary equipment using standard al-
ternating power supply. Danfoss  does 
not  warrant  the  compressors  for  use 
on mobile applications such as trucks, 
railways, subways, ships etc.

These  selection  and  application  gui-
delines  concern  single  compressors  
only.  For  guidelines  on  manifolding 
Maneurop®  NTZ  compressors,  please 
refer to literature called "Parallel Appli-
cation Guidelines".

Evaporator

To condenser

Loop, as high as top  

of condenser

max. 4 m

max. 4 m

U-trap, as short as possible

U-trap

8 to 12 m/s

0.5 % slope,

4 m/s or more

U-trap, as short as possible

U-trap

0.5 % slope,

4 m/s or more

Condenser

12

SYSTEM DESIGN RECOMMENDATIONS

Piping design

Oil  in  a  refrigeration  circuit  is  requi-
red  to  lubricate  moving  parts  in  the 
compressor.  During  normal  system 
operation  small  oil  quantities  will 
continuously  leave  the  compressor, 
with the discharge gas. Therefore, the 
system  piping  shall  be  designed  in  a 
way  which  allows  a  good  oil  circula-
tion, avoiding oil being trapped in the 
system  and  ensuring  a  constant  oil 
return  to  the  compressor.  As  long  as 
the amount of oil circulating through 
the system is small it will contribute to 

good system operation and improved 
heat transfer efficiency. 

Lubricant  getting  trapped  in  the  
evaporator  or  suction  lines  will  affect 
system  performance  and  will  ultima-
tely  lead  to  compressor  lubrication 
failures. Where a poor oil return situa-
tion  exists,  adding  lubricant  will  not 
help  safeguard  the  compressor.  Only 
a  correct  piping  design  can  ensure  
adequate  oil  circulation  maintaining 
safe oil level in the compressor.

Horizontal  suction  line  sections  shall 
have  a  slope  of  0.5%  in  the  direction 
of  refrigerant  flow  (5  mm  per  meter).
The cross-section of horizontal suction 
lines  shall  be  such  that  the  resulting 
gas velocity is at least 4 m/s. In vertical 
risers, a gas velocity of 8 to 12 m/s is 
required to ensure proper oil return. A 

U-trap  is  required  at  the  foot  of  each 
vertical riser. If the riser is higher than 
4 m, additional U-traps are required for 
each additional 4 meters.The length of 
each  U-trap  must  be  as  short  as  pos-
sible  to  avoid  the  accumulation  of 
excessive  quantities  of  oil  (see  figure 
below).

Suction line

Summary of Contents for Maneurop NTZ048

Page 1: ...RECIPROCATING COMPRESSORS Selection Application Guidelines Reciprocating Compressors NTZ R404A R507A Low temperature refrigeration ...

Page 2: ...ase motor protection and suggested wiring diagram 10 Single phase electrical characteristics 10 Single phase motor protection and suggested wiring diagram 10 REFRIGERANTS AND LUBRICANTS 11 SYSTEM DESIGN RECOMMENDATIONS 12 Piping design 12 Operating limits 14 Motor protection 15 Discharge temperature protection 15 Liquid refrigerant control and charge limits 16 SOUND AND VIBRATION MANAGEMENT 18 Sou...

Page 3: ... existing LTZ range The NTZ series is engineered as a true low temperature compressor opti mised at 35 C with an extended evaporating temperature range from 45 C up to 10 C The compressors can be operated at a return gas tem perature suction gas temperature of 20 C even at low evaporating temperatures A liquid injection system is not re quired All components are of high quality and precision to as...

Page 4: ...60 460 3 60 400 3 50 230 1 50 230 3 50 575 3 60 500 3 50 380 3 60 NTZ048 120F0001 NTZ068 120F0002 NTZ096 120F0003 NTZ108 120F0004 NTZ136 120F0005 NTZ215 120F0006 NTZ271 120F0007 Compressor model Code no Motor voltage code 1 3 4 5 6 7 9 Nominal voltage 208 230 1 60 200 230 3 60 460 3 60 400 3 50 230 1 50 230 3 50 575 3 60 500 3 50 380 3 60 NTZ048 120F0008 NTZ068 120F0009 NTZ096 120F0010 NTZ108 120F...

Page 5: ...886 1 19 4 3 9 62 NTZ271 271 47 3 57 0 6955 1 24 8058 1 21 4 3 9 64 SPECIFICATIONS Technical specifications and nominal ratings Maneurop NTZ compressors comply with the following approvals and cer tificates Operating envelope R404A R507A Operating conditions R404A Evap temp 35 C Cond temp 40 C RGT 20 C SC 0K Approvals and certificates CE European Directive All models UL Underwriters Laboratories Mode...

Page 6: ...alisation 3 8 Schrader 1 4 35 37 118 68 Suction 147 Discharge 142 39 123 159 Threaded oil sight glass 141 263 17 17 ø 224 HM8 40 23 15 Silent block 6 1 cylinder OUTLINE DRAWINGS Rotolock connections size Pipe sizing Rotolock valve Suction Discharge Suction Discharge Suction Discharge NTZ048 NTZ068 1 1 4 1 5 8 1 2 V09 V06 ...

Page 7: ... 145 125 188 171 8 38 82 74 68 265 Suction rotolock 1 3 4 Discharge rotolock 1 1 4 Oil equalisation 3 8 HM8 40 23 15 Silent block 7 OUTLINE DRAWINGS 2 cylinders Rotolock connections size Pipe sizing Rotolock valve Suction Discharge Suction Discharge Suction Discharge NTZ096 NTZ108 1 3 4 1 1 4 7 8 3 4 V07 V04 NTZ136 1 3 4 1 1 4 1 1 8 3 4 V02 V04 ...

Page 8: ...r 1 4 Mounting hole for PTC crankcase heater Suction rotolock 1 3 4 Discharge rotolock 1 1 4 Oil equalisation 3 8 VE version only Rotolock connections size Pipe sizing Rotolock valve Suction Discharge Suction Discharge Suction Discharge NTZ215 NTZ271 1 3 4 1 1 4 1 1 8 3 4 V02 V04 30 19 HM12 50 H M12 50 Silent block 8 OUTLINE DRAWINGS ...

Page 9: ... 632 V 60 Hz 9 380 V 3 60 Hz 342 418 V Models NTZ048 NTZ068 NTZ096 NTZ108 NTZ136 Models NTZ215 NTZ271 Three phase electrical characteristics Compressor model Winding resistance between phases 7 at 25 C Ohm LRA Locked Rotor Amp A MCC Maximum Conti nuous Current A RLA Rated Load Amps A NTZ048 4 11 55 16 4 8 3 4 NTZ068 4 7 11 25 8 4 6 0 NTZ096 4 5 03 32 10 1 7 2 NTZ108 4 4 00 45 12 1 8 6 NTZ136 4 3 8...

Page 10: ...otected by a temperature current sensing bimetallic protector which senses the main and start win ding current as well as motor winding temperature If the motor were to be overloaded and the protector trips it might take up to several hours to reset and restart the compressor The standard CSR wiring system pro vides additional motor torque at start up by the use of a start capacitor in combination...

Page 11: ... HCFC Hydrochlorofluorcarbon with chlorine component ODP Ozone Depletion Potential base R11 ODP 1 Temperature glide difference between saturated vapor temperature and saturated liquid temperature at constant pressure Montreal protocol In such installation the factory charged polyolester POE lubricant must be replaced by mineral oil The use of hydrocarbons is not autho rised in NTZ compressors Only a...

Page 12: ...g trapped in the system and ensuring a constant oil return to the compressor As long as the amount of oil circulating through the system is small it will contribute to good system operation and improved heat transfer efficiency Lubricant getting trapped in the evaporator or suction lines will affect system performance and will ultima tely lead to compressor lubrication failures Where a poor oil retur...

Page 13: ... specific systems may differ from these average sizes The suction line must always be insu lated to limit suction gas superheat Oil charge and oil separator Filter driers For new installations with NTZ com pressors Danfoss recommends using the Danfoss DML 100 molecular sieve solid core filter drier Molecular sieve filter driers with loose beads from third party suppliers shall be avoided For servicing...

Page 14: ...ed off by the low pressure protection Depending on how the low pressure switch and delay timer are set short cycling can occur To avoid these problems several solu tions are possible based on reducing condenser capacity Liquid flooding of condensors note this solution requires extra refri gerant charge A non return valve in the discharge line is required and special care should be taken when designi...

Page 15: ...ip at not more than 140 of the RLA value A circuit breaker shall be selected to trip at not more than 125 of the RLA value Further requirements for the external protector are Over current protection the protec tor must trip within 2 minutes at 110 of the Maximum Continuous Current MCC The MCC value is listed in the table on page 9 and stamped as A max on the compressor nameplate Locked rotor prote...

Page 16: ...uring operation During system standstill and after pressure equalisation refrigerant will condensate in the coldest part of the system which may be the compressor when it is placed in a cold environ ment Ultimately the full system refri gerant charge can condensate in the compressor crankcase A large amount will dissolve in the compressor oil un til the oil is completely saturated with During norm...

Page 17: ...st be positio ned on the compressor shell as close as possible to the oil sump to ensure good heat transfer to the oil The be low illustrated mounting positions are recommended Belt crankcase heaters are not self re gulating Control must be applied to energise the belt heater once the com pressor has been stopped and then to de energise it while the compressor is running The belt heater must be en...

Page 18: ...losed in a sound proo fing material lined compartment Sound transmitted by mounting feet pipework and refrigerant should be treated the same way as vibration see next section Vibration The mounting grommets delivered with the compressor should always be used They will largely attenuate the compressor vibration transmit ted to the base frame These rubber grommets have been selected and calculated in...

Page 19: ...vacuum pumps etc dedicated for R404A and R507A Compressor handling mounting and connection Maneurop NTZ compressors must be handledwithcareandallhandlingpro cedures must be performed smoothly and gently Each NTZ has been fitted with one lift ring which shall always be used to lift the compressor Once the compressor is installed the lift ring shall never be used to lift the complete installation Alw...

Page 20: ...mpressor via the schrader valve to prevent air and moisture ingress Purging must start when the plugs are removed and pro ceeded during the brazing process When rotolock valves are used on the compressor they shall be closed im mediately after mounting thus kee ping the compressor isolated from atmosphere or from a not yet dehy drated system Note when the compressor is built into a pack or rack co...

Page 21: ...7 mbar A two sta ge vacuum pump shall be used with a capacity appropriate for the system volume It is recommended to use connection lines with a large diame ter and to connect these lines to the service valves and not to the schrader connection so as to avoid excessive pressure losses 3 Once the vacuum level of 500 mi crons has been reached the system must be isolated from the vacuum pump Wait 30 ...

Page 22: ... is recommended to keep the suction gas superheat at a lower value to increase the compres sor performance and service life On the other hand note that extremely low superheat values can increase the risk of unwanted liquid floodback to is a near azeotropic mixture and must be charged in the liquid phase R507A is an azeotropic mixture and can be charged either in liquid or gas phase Warning When a ...

Page 23: ......

Page 24: ... Danfoss reserves the right to alter its products without notice This also applies to products already on order provided that such alterations can be made without subsequential changes being necessary in specifications already agreed All trademarks in this material are property of the respective companies Maneurop Danfoss and the Danfoss logotype are trademarks of Danfoss A S All rights reserved ww...

Reviews: