Danfoss Inverter scroll compressors VZH hybrid manifold VZH Gen3 DSH Application guide

Application guidelines

Inverter scroll compressors

VZH hybrid manifold VZH Gen3+DSH

R410A

http://cc.danfoss.com

Contents

GENERAL INFORMATION ....................................................................................................4

Scope ...................................................................................................................................................................................... 4

Beneﬁts .................................................................................................................................................................................. 4

PRODUCT INFORMATION ...................................................................................................5

Oil management concept ....................................................................................................5

System conﬁguration .......................................................................................................................................................5

Dimensions ...........................................................................................................................8

Tandem .................................................................................................................................................................................. 8

Design pipe .......................................................................................................................................................................... 9

General requirements ...................................................................................................................................................... 9

Suction separator .............................................................................................................................................................11

Oil equalization design .................................................................................................................................................. 11

Design compressor mounting ..........................................................................................12

General requirements ....................................................................................................................................................12

VZH178H Mounting feet ................................................................................................................................................ 12

VZH208H Mounting feet ............................................................................................................................................... 12

VZH257H / VZH278H Mounting feet .........................................................................................................................12

VZH301H Mounting feet ................................................................................................................................................13

VZH410H / VZH465H Mounting feet .........................................................................................................................13

VZH354H Mounting kit .................................................................................................................................................. 13

Design oil level sensor .......................................................................................................14

General requirements ....................................................................................................................................................14

Manage operating envelope .............................................................................................15

Requirement ...................................................................................................................................................................... 15

Manage speed limit ............................................................................................................16

General requirements ....................................................................................................................................................16

Manage superheat .............................................................................................................17

Requirement ...................................................................................................................................................................... 17

System evaluation ...........................................................................................................................................................17

Test, criteria and solutions ............................................................................................................................................ 17

Manage oﬀ-cycle migration ..............................................................................................19

Requirement ...................................................................................................................................................................... 19

System evaluation ...........................................................................................................................................................19

Refrigerant charge limit table ..................................................................................................................................... 19

Manage oil in the circuit ................................................................................................... 20

Oil management system for hybrid manifolding ................................................................................................20

Oil management logic ...................................................................................................................................................20

Requirement ......................................................................................................................................................................21

System evaluation ...........................................................................................................................................................21

Test, criteria and solutions ............................................................................................................................................21

Control logic ...................................................................................................................... 22

Safety control logic requirements .............................................................................................................................22

Short cycle protection....................................................................................................................................................22

Defrost logic recommendations ................................................................................................................................23

Pump-down logic recommendations ......................................................................................................................23

Assembly line procedure .................................................................................................. 24

Handling ..............................................................................................................................................................................24

Ordering information .....................................................................................................................................................25

ORDERING INFORMATION .............................................................................................. 25

Compressor ordering codes ........................................................................................................................................25

Accessory ordering codes .............................................................................................................................................25

Accessories ......................................................................................................................... 26

Annex ................................................................................................................................. 28

3AB298632269085en-000401

General information

Scope

Beneﬁts

The application guideline describes the operating characteristics, design features and application requirements for hybrid manifolding of the Danfoss DSH ﬁxed-speed compressor and the VZH inverter compressor in air-conditioning and heat pump applications.

To ensure proper parallel installation and running conditions, the following recommendations must be followed:

A parallel compressor installation refers to a system of interconnected compressors with a common suction line and a common discharge line. The technique of mounting compressors in parallel is also called manifolding. The hybrid manifolding in this application guideline refers to the manifolding of the Danfoss inverter compressor (VZH) and ﬁxed speed compressor (DSH), which has several beneﬁts.

• It is essential to respect all the instructions given in these guidelines; please refer to the instruction leaﬂet supplied with each compressor and the application guidelines for single compressors.

• For additional system components related to speciﬁc application requirements, the supplier recommendations must always be respected.

The main reason is reduced operating cost through controlling capacity and power consumption to a greater extent. This is achieved by both staggering the compressor switch-on sequences and regulating the speed of the inverter compressor which allows the parallel system to continuously match its power with the capacity needed.

PRODUCT INFORMATIONSYSTEM DESIGNORDERING INFORMATION GENERAL INFORMATION

Capacity

Compressor n°1

VZH 25-100 rps

A second reason for manifolding the inverter compressor and the ﬁxed speed compressor is improved part-load eﬃciency. In the variable speed+ﬁxed speed parallel installation, the system can run either only the inverter compressor at lower load or both the inverter and ﬁxed speed compressors at a higher load with the ﬁxed speed compressor operating at 100% load.

Compressor n°1

VZH 25-100 rps

Compressor n°2

xed speed DSH

Therefore, it will be possible to achieve a higher part-load eﬃciency.

Thirdly, the capacity of the hybrid manifolding system can be widely regulated, for example 10% to 100%. The continuous capacity regulation allows for accurate temperature control and a comfortable indoor environment.

4 AB298632269085en-000401

Oil management concept

System conﬁguration

Hybrid manifolding systems use the dynamic system for oil balance. The suction connections between the two individual compressors are interconnected by a special suction separator design that allows most of oil feed into variable speed compressors.

Discharge line

VZH

DSH

An optical-electrical oil level sensor ﬁxed in a variable speed compressor monitors the compressor oil level.

If the oil level drops below the limit, the OEM main controller activates the oil management logic.

Drive

ModBus

OEM main controller

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

Oil equalization tube Suction separatorSuction line

Optical oil level sensor

5AB298632269085en-000401

Oil management concept

Return Gas

Oil-rich gas ﬂow

Oil poor gas ﬂow

FS VS

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

Downstream compressor

Upstream compressor

The hybrid manifolding system uses the dynamic system for oil balance.

The suction connections of the two individual compressors are interconnected by a suction separator that integrates with the suction oil separator and the gas restrictor. The variable speed compressor (VS) is installed in the upstream position which appears ﬁrst on suction line and ﬁxed speed compressor (FS) is installed on downstream position.

The oil which clings back along the main suction line is separated by the suction separator which

Suction separator (Oil separator/gas restrictor)

returns most of the oil in the suction gas to the upstream compressor. The suction separator creates a slight pressure drop to ensure lower sump pressure between two compressors are well balance when ﬁxed speed compressor is ON and the inverter compressor is running at maximum speed. When the variable speed compressor runs at any frequency below maximum speed, the sump pressure in the ﬁxed speed compressor is lower than the variable speed compressor, and driven by the sump pressure diﬀerence, the excess oil from the variable speed compressor runs into the ﬁxed speed compressor sump.

6 AB298632269085en-000401

Oil management concept

Approved hybrid tandem conﬁgurations and capacity range

Diﬀerent conﬁgurations of hybrid tandems are possible. All VZH models (high/low pressure ratio/ diﬀerent voltage) could be manifolded with ﬁxed speed compressors.

Danfoss VSD : VZH compressor DriveTM 380-480 Volt

Model Description

VZH178 H VZH088+DSH90 68.9 19.6 73.9 21.0 VZH208H VZH088+DSH120 77.7 22.1 83.7 23.8 VZH257H VZH117+DSH140 9 7. 8 27.8 105. 2 29.9 VZH278H VZH117+DSH161 101.6 28.9 110.1 31.3 VZH301H V ZH117+DSH184 106.2 30.2 115 .7 32.9 VZH354H VZH170+DSH18 4 137 39.1 146 41.9 VZ H410H VZH170+DSH240 151.9 43.2 164.9 46.9 VZH465H VZH170+DSH295 164.6 46.8 179. 3 51

TR: Ton of Refrigeration Refrigerant: R410A

Standard rating conditions: ARI standard Evaporating temperature: 7.2°C Superheat: 11.1k

Condensing temperature: 54.4°C Subcooling: 8.3k

Subject to modiﬁcation without prior notiﬁcation

Data given for motor code G compressor – for full data details and capacity tables, please refer to Coolselector2

www.coolselector.danfoss.com

FS: 50Hz, VS:100Hz FS: 60Hz, VS: 100Hz

kW TR kW TR

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

7AB298632269085en-000401

Dimensions

Tandem

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

 

H H

Tandem model Composition

VZH178 H VZH088+DSH090

VZH208H VZH088+DSH120

VZH257H VZH117+DSH140

VZH278H VZH117+DSH161

VZH301H VZH117+DSH184

VZH354H VZH170+DSH184

VZ H410H VZH170+DSH240

VZH465H VZH170+DSH295

Tandem conﬁgurations are achieved by assembling individual compressors

Outline drawing

number

               

8560156 1" 5/8 1" 3/8 1011 445 482

8560155 1" 5/8 1" 3/8 811 445 482

8560154 1" 5/8 1" 3/8 1011 445 540

8560153 1" 5/8 1" 3/8 811 445 540

8560152 1" 5/8 1" 3/8 1024 445 540

8560151 1" 5/8 1" 3/8 811 445 540

8560152 1" 5/8 1" 3/8 1024 445 540

8560151 1" 5/8 1" 3/8 811 445 540

8560150 1" 5/8 1" 3/8 111 6 445 555

8560149 1" 5/8 1" 3/8 811 445 555

856014 8 2" 1/8 1" 5/8 1241 583 682

8560147 2" 1/8 1" 5/8 890 583 682

8556271 2" 1/8 1" 5/8 1245 583 682

8556270 2" 1/8 1" 5/8 953 583 682

8556271 2" 1/8 1" 5/8 1245 583 682

8556270 2" 1/8 1" 5/8 953 583 682

Suction Discharge L (mm) D (mm) H (mm)

8 AB298632269085en-000401

Design pipe

General requirements Proper piping practices should be employed to:

1. Ensure adequate oil return, even under minimum load conditions (ﬁxed speed compressor oﬀ, variable speed compressor at minimum speed, minimum evaporating conditions). If minimum refrigerant velocity cannot be reached, it is strongly recommended that an oil separator is used. For a validation test, the see section “Manage oil in the circuit”.

To condenser

0.5% slope

max. 4 m

4 m/s or more

U-trap, as short as possible

8-12 m/s

Evaporator

0.5% slope

4 m/s or more

2. Prevent condensed liquid refrigerant from draining back into the compressor when stopped (discharge piping upper loop). For validation tests, see the section “Manage oﬀ-cycle migration”.

General recommendations are described in the ﬁgures below:

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

U trap, as short as possible

Upper loop

3D ﬂexibility

3. Piping should be designed with adequate three-dimensional ﬂexibility to avoid excess vibration. It should not be in contact with the surrounding structure, unless a proper tubing mount has been installed. For more information

Condenser

on noise and vibration, see the section “Sound and vibration management” in the application guideline for Danfoss VZH Gen3 scroll compressors (AB300034185311en).

9AB298632269085en-000401

Design pipe

Suction on left Suction on right

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Variable speed

Fixed speed

Fixed speed Variable speed Tandem model Suction direction

DSH090 VZH088 V ZH178H Left/Right

DSH120 VZH088 VZH208H Left/Right

DSH140 VZH117 VZH257H Left/Right

DSH161 VZ H117 VZH278H Left/Right

DSH184 V ZH117 VZH301H Left/Right 50 & 60 120Z0656

DSH184 VZH170 VZH354H

DSH240 V ZH170 VZH410H Left/Right 50 & 60 120Z0657

DSH295 V ZH170 VZH465H Left/Right 50 & 60 120Z0655

Note: The tandem accessory includes oil equalization kits and oil level sensor. For compressors that need a UL certiﬁcate, please order the accessory kit with the 24V oil level sensor.

Left

Right

Hz of FS

compressor

50 120Z0 676

60 12 0Z0675

50 120Z0664

60 120Z0658

50 120Z0666

60 120Z0665

50 120Z0665

60 120Z 0674

Fixed speed

Suction

separator code

120Z0683

120Z0655

120Z0 687

Variable speed

Tandem accessory kit code

120Z0653 (with 24V oil level sensor)