Low-emission microturbine electric power supply NETZ

The low-emission microturbine electric power supply NETZ represents successful realisation of a co-generation unit based on a combustion microturbine that is directly attached to a high-frequency generator. The high-frequency generator supplies electric power through the power electronics to the grid.

Electric power can serve for satisfying own user's requirements or can be fed to a distribution grid. Output heat from exhaust gases can be used for heating water or saturated vapour. Hot water or saturated vapour can be used for producing cooling via absorption cycle. Efficiency of the overall system is increased by utilisation of hot gas from the micro-turbine.

The NETZ control system is fully modular and consists of a biomass generator, combustion control system, power converter, high-speed micro turbine with a generator, and starter converter. Modularity of the NETZ system allows its easy modification according to user requirements.

Biomass Generator

The biomass generator (BG100) is a highly efficient technology capable of producing 100kW of renewable electricity and 200kW of renewable heat. The system is run on biomass which can be considered as solar energy stored in the chemical bonds of trees and plants, making it a renewable and sustainable source of energy. The BG100 is capable of utilizing a wide range of biomass fuels. Its main advantages are easy to use controls, high temperature combustion for maximum efficiency, flexible fuel loading and high efficiency biomass turbine generator.

High speed micro-turbine with generator

Bio-gas micro-turbine with a permanent magnet synchronous generator. The main advantages of the microturbine, compared to piston engines, are smaller dimensions, cost-effective maintenance, longer life-time, lower NOx emisions, and lower noisiness.

Power and control electronics

Power and control electronics consists of the following subsystems:

• Control and display unit
• Power converter
• Starter converter
• Starting battery a with battery charger
• Protection control system

Power converter

UNIS’ static power converter for micro turbine applications is designed to start and control a permanent magnet synchronous generator directly coupled to a micro-turbine, and to convert the generator’s high frequency output voltage to 400V/50Hz(60Hz) for supply to the grid or to a stand-alone load. The converter’s output power is 100 kVA with peak efficiency up to 97%. The static power converter utilizes a modular concept, which enables easy modification according to customer requirements, software configuration and application of different control algorithms.

Combustion control system

The combustion control system ensures that the system is fed with the right amount of fuel to maintain the required energy output. Exhaust combustion gases are fed through a heat exchanger back to the combustion chamber to support the high temperature combustion process. High combustion temperatures ensure clean combustion, meeting all environmental standards. The step-grate system with auto de-asher ensures an even burn throughout the combustion chamber for improved efficiency

Starter converter

IGBT based starter convertor with nominal power up to 3 kW.

Special accessories

According to customer requirements the NETZ system can be connected with the following accessories:

• GSM module
• relay interface
• www interface

Functional scheme

Technical specification

Overall NETZ system

Maximum electric power:	100 kVA
Maximum heat power:	163 kW
Electric efficiency at power converter output:	30,4%
Overall efficiency of the NETZ:	78,3% (with recuperation)
Dimensions (l x w x h):	2300 x 900 x 1700 mm
Weight:	1600 kg

Turbogenerator chassis

Maximum electric power:	110 kVA
Maximum mechanical power:	133 kW
Nominal rpm speed:	56 000 ot/min
Efficiency of the generator:	95%
Overall efficiency of microturbine:	33,7% (with recuperation)
Natural gas consumption:	25 kg/h

Power and control electronics

Nominal electric power:	100 kVA
Output power:	3 x 230 V / 400 V / 50 Hz (60 Hz), can be customized to costumer requirements
Power converter efficiency:	95%
Dimensions (l x w x h):	600 x 600 x 1300 mm
Weight:	250 kg

Possible applications of NETZ

Low-emission microturbine electric power supply NETZ can be used in the following areas:

• industrial companies
• trade and office buildings
• schools
• hospitals
• hotels
• bureaus
• etc...

One of the main benefits of the NETZ power supply system is possibility of its utilization in intermittent operation with relatively small amount of operational hours (especially during peak hours or high tarrif of electric energy).