Jump to the main text

Compressor : Hitachi

Hitachi

We can make energy conservation proposals for the compressors you already have.

New intelligent operating panel

Intelligent control is becoming the world standard for compressors

Image: Oil-free screw compressor + New intelligent operating panel = Next-generation world standard

In addition to high quality and reliability, Hitachi oil-free screw compressors (SDS-NH series) offer total running cost reductions through high-efficiency and long maintenance cycles.

Building on these features, you can achieve a variety of energy conservation and labor cost savings. In particular, you can now conserve energy by precisely controlling discharge pressure and preventing unnecessary high pressure running.

Keeping one step ahead of the needs of a new era, this is the new intelligent operating panel for the detaching SDS compressor.

Example of active power control (APC)

Overview

The new intelligent operating panel calculates the air consumption and line pressure loss associated with it, and automatically controls the loaded/unloaded pressure measurement value so that plant pressure remains consistent. Automatic operation is performed corresponding to changes in the air consumption (pressure control), which results in energy savings. This is truly the next generation in compressor control.

When air consumption is 100%
Compressor discharge pressure Line pressure loss Plant pressure
0.69(7.0) 0.10(1.0) 0.59(6.0)
When air consumption changes to 50%
Control method Output pressure Pressure losses Plant pressure Effects
Existing 0.69(7.0) 0.03(0.3) 0.66(6.7) Wasteful high-pressure operation
APC 0.62(6.3) 0.03(0.3) 0.59(6.0) Operation at optimal pressure
*
MPa(kgf/cm²G)

This animation demonstrates operations at optimal discharge pressure.

Energy conservation trial calculation

Compressor operating example

  • Compressor model (motor output, discharge pressure): SDS-280(280kW, 0.69MPa(7kgf/cm²G))
  • Total annual running time (24hours×5days/week×50days/year): 6,000hours
  • Power consumption units: 15¥/kWh
  • Line pressure loss when compressor is running at 100% air capacity: 0.12MPa(1.2kgf/cm²G)
  • Compressor running average load rate (running time): 90% (3,000 hours), 50% (3,000 hours)

Using this operation example, we can calculate the power consumption when the active control is on or off.

Example of power saving control (PSC)

Overview

Energy is conserved by reducing the unloaded pressure in response to the load ratio of the air compressor and cutting air pressure.

Control method Compressor unload pressure Compressor load pressure Compressor average output pressure
Existing 0.71(7.2) 0.66(6.7) 0.68(6.95)
PSC 0.68(6.9) 0.66(6.7) 0.67(6.8)
*
MPa(kgf/cm²G)

Here is an animation comparing a conventional compressor with a compressor which is provided with the power saving control.

Energy conservation trial calculation

Compressor operating example

  • Compressor model (motor output, discharge pressure): SDS-280(280kW, 0.69MPa(7kgf/cm²G))
  • Total annual running time (24hours×5days/week×50days/year): 6,000hours
  • Power consumption units: 15¥/kWh
  • Compressor running average load ratio (running time)
*
The pressure control range with the power saving feature is 0.2kg/cm²G

We calculate the power consumption when the power saving control is on and off using an operating example.

Example of cutting power and automatic startup

Overview

”Cutting power” means that line pressure will increase until a predetermined pressure setting is reached, and the compressor will automatically be stopped when the unloaded state continues beyond the set time. When the line pressure goes down to the setting pressure, autostart automatically starts the compressor.

Image: Pressure-electric power graph

Example of energy savings calculation

  • Compressor model (motor output, discharge pressure): SDS-280(280kW, 0.69MPa(7kgf/cm²G))
  • Total annual running time (24hours×5days/week×50days/year): 6,000hours
  • Power consumption units: 15 ¥/kWh
  • Compressor running average load ratio (running time)
* When stopped by cutting power instead of running unloaded three times a day during idle times (morning, noon, night) 30 minutes each
Control method Number of rests Compressor operational data Running hours/times Total annual number of times
Existing 3 times/day Unloaded operation 0.5 hours 1.5hours/days×250days/year
Cutting power 3 times/day Compressor stopped by cutting power 0.5 hours 1.5hours/days×250days/year

Example of simple operating panel loaded with energy conservation features

Overview

Photograph: Simple operating panel

*
The image above is an embedded composite image diagram.
* When stopped by cutting power instead of running unloaded three times a day during idle times (morning, noon, night) 30 minutes each
Display image Display during standby Local or remote (operating location), during scheduled operations, automatic start/stop, during automatic start/standby
Display operation example Capacity control air pressure, load status (0-100%), oil temperature, etc.
Preventative maintenance display Intake air filter dirt, air cooler dirt, oil cooler dirt, add motor grease, auxiliary unit inspection, main unit inspection, etc.
Minor/serious breakdown display Detection location of minor breakdowns (temperature, pressure, etc.) + message, detection location of serious breakdowns (temperature, pressure, etc.) + message, pressure drop (lower limit), etc.
Menu selection display Control settings Capacity control pressure, power saving, power cut, active power control, automatic start/stop setting
Display of operating information Operational status (date/time, status of energy-saving function set up, scheduled running timer, etc.), temperature and pressure, running time, number of unloaded cycles, number of running cycles, operational pressure (4-20 mA) output status
Display of operational history Operating information is stored, read out, and displayed 24 times each hour
Preventative maintenance history Operating information is stored, called up, and displayed when all preventative maintenance is displayed
History of minor and serious breakdowns Information on minor and serious breakdowns is stored, called up, and displayed

Example for a relay panel

Image: Exterior and operating panel
Exterior view

*
The image above is an embedded composite image diagram.
Description of change work
  Item Description Quantity Notes
1 Intelligent panel Newly-added product 1 With Ammeter
2 Door panel Replace with new 1 Hinge adjustment available
3 Temperature sensor Replace 3 2nd intake and discharge, oil
Newly-added product 2 Coolant water inlet-outlet: Make holes in base
1 After-cooler outlet: Has pipe seat
4 Pressure sensor Newly-added product 3 Has pipe seat
5 Indicator rack Replace with new 1 Pressure switch is installed in interior post of the new solenoid valve sound-reducing cover
6 Piping magnetic wiring work - 1 Added copper pipe (partially vinyl hose)
Lead in pipes
7 Starting panel operating circuit Newly-added product 1 Installation and wiring in starting panel