Danfoss VZH hybrid manifold Application guide

Application guidelines

Inverter scroll compressors

VZH hybrid manifold

R410A

http://cc.danfoss.com

Contents

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

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

Benets .................................................................................................................................................................................. 4

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

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

System conguration .......................................................................................................................................................5

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

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

SYSTEM DESIGN ...................................................................................................................9

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

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

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

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

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

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

VZH178 Mounting feet ...................................................................................................................................................12

VZH208 Mounting feet ..................................................................................................................................................12

VZH257 / VZH278 Mounting feet ...............................................................................................................................12

VZH301 Mounting feet...................................................................................................................................................13

VZH350 / VZH410 / VZH465 Mounting feet ........................................................................................................... 13

VZH354 Mounting kit ..................................................................................................................................................... 13

Manage operating envelope .............................................................................................14

Requirement ...................................................................................................................................................................... 14

Manage superheat .............................................................................................................15

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

System evaluation ...........................................................................................................................................................15

Test, criteria and solutions ............................................................................................................................................ 15

Manage o-cycle migration ..............................................................................................17

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

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

Refrigerant charge limit table ..................................................................................................................................... 17

Manage oil in the circuit ....................................................................................................18

Oil management system for hybrid manifolding ................................................................................................18

Oil management logic ...................................................................................................................................................18

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

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

Test, criteria and solutions ............................................................................................................................................ 19

Control logic ...................................................................................................................... 20

Safety control logic requirements .............................................................................................................................20

Cycle rate limit requirements ......................................................................................................................................20

Defrost logic recommendations ................................................................................................................................20

Pump-down logic recommendations ......................................................................................................................21

Assembly line procedure .................................................................................................. 22

Handling ..............................................................................................................................................................................22

ORDERING INFORMATION .............................................................................................. 23

Compressor ordering codes ........................................................................................................................................23

Accessory ordering codes .............................................................................................................................................23

Accessories ......................................................................................................................... 24

Annex ................................................................................................................................. 26

3FRCC.PC.049.A3.02

General information

Scope

Benets

The application guideline describes the operating characteristics, design features and application requirements for hybrid manifolding of the Danfoss SH xed-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 xed speed compressor (SH), which has several benets.

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

• For additional system components related to specic 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 xed speed compressor is improved part-load eciency. In the variable speed+xed speed parallel installation, the system can run either only the inverter compressor at lower load or both the inverter and xed speed compressors at a higher load with the xed speed compressor operating at 100% load.

Compressor n°1

VZH 25-100 rps

Compressor n°2

xed speed SH

Therefore, it will be possible to achieve a higher part-load eciency.

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 FRCC.PC.049.A3.02

Oil management concept

System conguration

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

An optical-electrical oil level sensor xed 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

Optical oil level sensor

Suction separatorSuction line

5FRCC.PC.049.A3.02

Oil management concept

FS VS

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

Downstream compressor

Upstream compressor

Suction separator (Oil separator/gas restrictor)

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 rst on suction line and xed 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

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 xed 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 xed speed compressor is lower than the variable speed compressor, and driven by the sump pressure dierence, the excess oil from the variable speed compressor runs into the xed speed compressor sump.

6 FRCC.PC.049.A3.02

Oil management concept

Approved hybrid tandem congurations and capacity range

Dierent congurations of hybrid tandems are possible. All VZH models (high/low pressure ratio/ dierent voltage) could be manifolded with xed speed compressors.

Danfoss VSD : VZH compressor DriveTM 380-480 Volt

Model Description

VZH178 VZH088+SH90 68.9 19.6 73.9 21.0 VZH208 VZH088+SH120 77.7 22.1 83.7 23.8 VZH257 VZH117+SH140 97.8 27. 8 105. 2 29.9 VZH278 VZH117+SH161 101.6 28.9 110 .1 31.3 VZH301 VZH117+SH184 106.2 30.2 115 .7 32.9 VZH350 VZH170+SH180 137. 5 39.1 147. 4 41.9 VZH354 VZH170+SH184 137. 0 39.1 146 .0 41.9 VZ H410 V ZH170+SH240 151.9 43.2 164.9 46.9 VZH465 V ZH170 +SH295 164.6 46.8 179. 3 51.0

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 modication without prior notication

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

7FRCC.PC.049.A3.02

Dimensions

Tandem

 

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

Tandem model Composition

VZH178 VZH088 + SH090

Outline drawing

number

 

VZH208 VZH088 + SH120

 

VZH257 VZH117 + SH140

 

VZH278 VZH117 + SH161

 

VZH301 VZH117 + SH184

 

VZH350 VZH170 + SH180

 

VZH354 VZH170 + SH184

 

VZ H410 VZH170 + SH240

 

VZH465 VZH170 + SH295

 

Tandem congurations are achieved by assembling individual compressors

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

8560108 1"5/8 1"3/8 1011 445 482

8560109 1"5/8 1"3/8 810 445 482

8560104 1"5/8 1"3/8 1011 445 540

8560105 1"5/8 1"3/8 811 445 540

8560106 1"5/8 1"3/8 1024 445 540

8560107 1"5/8 1"3/8 811 445 540

8560106 1"5/8 1"3/8 1024 445 540

8560107 1"5/8 1"3/8 811 445 540

8556183 1"5/8 1"3/8 1116 445 555

8556184 1"5/8 1"3/8 811 445 555

8556181 2"1/8 1"5/8 1233 550 682

8556182 2"1/8 1"5/8 953 550 682

8556188 2"1/8 1"5/8 1241 550 682

8556189 2"1/8 1"5/8 890 550 682

8556181 2"1/8 1"5/8 1233 550 682

8556182 2"1/8 1"5/8 953 550 682

8556181 2"1/8 1"5/8 1233 550 682

8556182 2"1/8 1"5/8 953 550 682

8 FRCC.PC.049.A3.02

Design pipe

General requirements Proper piping practices should be employed to:

1. Ensure adequate oil return, even under minimum load conditions (xed speed compressor o, 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”.

0.5% slope

4 m/s or more

max. 4 m

U-trap, as short as possible

8-12 m/s

max. 4 m

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 o-cycle migration”.

General recommendations are described in the gures below:

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

To condenser

Evaporator

U trap, as short as possible

Upper loop

3D exibility

3. Piping should be designed with adequate three-dimensional exibility 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 scroll compressors (FRCC.PC.023).

9FRCC.PC.049.A3.02

Design pipe

Suction on left Suction on right

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Variable speedVariable speed

Fixed speed Fixed speed

Fixed speed Variable speed Tandem model Suction direction

SH090 VZH088 VZH178 Left/Right

SH120 VZH088 VZH208 Left/Right

SH14 0 VZ H117 VZH257 Left/Right

SH161 V ZH117 VZH278 Left/Right

SH184 V ZH117 VZH301 Left/Right 50 & 60 120Z0 656

SH180 VZH170 VZH350 Left/Right 50 & 60 120Z0657

SH184 VZH170 VZH354

SH240 VZH170 VZH410 Left/Right 50 & 60 120 Z06 57

SH295 VZH170 VZH465 Left/Right 50 & 60 120 Z0655

Note: The tandem accessory includes oil equalization kits and oil level sensor. For compressors that need a UL certicate, 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 120Z066 5

50 120Z 066 5

60 120Z0 674

Suction separator

code

120Z0683 120Z0682 (with 24V oil level sensor)

120Z0683 120Z0681 (with 230V oil level sensor)

120Z0 655 120Z0682 (with 24V oil level sensor)

120Z0 655 120Z0681 (with 230V oil level sensor)

120Z0 687 120Z0682 (with 24V oil level sensor)

120Z0 687 120Z0681 (with 230V oil level sensor)

120Z0 687 120Z0682 (with 24V oil level sensor)

120Z0 687 120Z0681 (with 230V oil level sensor)

Tandem accessory kit code

120Z0653 (with 24V oil level sensor)