What is an Inverter Generator?

Unless you are in the electrical industry, live in an area prone to weather disasters or take regular camping trips, generators are not something you likely speak about on a regular basis. Generators are used to power electronic items when there is a blackout or you are in an area that isn’t serviced by power (for example, when you are out in the wilderness), and there are three main kinds - portable, inverter and standby.

Inverter generators are used in various renewable energy arrangements, including both solar and cogeneration. But, you are probably wondering (seeing as though you are still on this page), what is an inverter generator? We will look into what an inverter generator is in relation to Combined Heat and Power (‘CHP’) and who uses them, as well as the varying operational modes and control systems. If you have any questions regarding inverter generators or cogeneration, give Inoplex a call on 0448 307 282 now and they can help!

What is an Inverter CHP Generator?

It may seem a little confusing, but let’s start at the beginning. An inverter generator is designed to produce more AC (alternating current) electrical energy per engine rotation than a conventional generator, but energy in that form can not be used directly for normal appliances. The raw energy must first be turned into DC (direct current) power and then is turned into AC in a usable form. So, how does this apply to CHP?

Inverter Generator

A CHP inverter generator is a high efficiency unit that is used to assist in powering a building or other arrangements, taking control of heat and power in variable speed load arrangements. An inverter CHP generator is made up of :

  • A prime mover or engine
  • A permanent magnet alternator
  • Power electronics or inverters
  • Heat recovery system
  • A programmable logic controller (‘PLC’) to manage and provide communications

All these parts work together to transform fuel, such as biogas or petrol, into a usable energy source.

There are generally 30, 50 and 66 KWe versions, as well as a 120 KWe version.

Who uses CHP inverter generators?

Now you are aware of what an inverter generator is, you’re probably wondering who uses them. There is a huge range of industries and businesses that utilise CHP inverter generators, including :

  • Energy efficient buildings
  • Aquatic centres
  • Data centres
  • Jails and correctional centres
  • Coal seam gas well-heads
  • Anaerobic digesters
  • Primary producers
  • Holiday parks
  • Resorts
  • Mines

CHP inverter style generator control system

Don’t be overwhelmed by the below picture - it is a visual representation of what a CHP control system looks like of an inverter. In order to meet all the electrical and thermal needs of a particular building, the control system must be appropriately configured to allow for a variety of combinations. 

CHP Control System
CHP Control System

As you can see, all the components that make up an inverter generator have a specific job, with the CHP controller being the centrepoint for all processes. There are also components such as the mains power supply and alternative power - these apply depending on the grid connect modes that apply to your building. These include :

Base Load Grid Connect Mode
Base Load Grid Connect Mode
Peak Demand Grid Connect Mode
Peak Demand Reduction Grid Connect Mode
Export to CHP Capacity Grid Connect Mode
Export to CHP Capacity Grid Connect Mode
Export only during day/high power charges Grid Connect Mode
Export Only During Day/High Power Charges Grid Connect Mode

Each mode applies to differing circumstances, so it is best to speak to your local CHP inverter professional who can assist further.

What are the operational modes of a CHP Inverter Generator?

There are a variety of operational modes that a CHP inverter generator can have, including:

- Combined Heat and Power Load Following

  • Controller checks site electrical and thermal load every second
  • Adjustments are made to the engine speed, configuration and water heating/cooling system to meet the relevant demands

- Power Priority

  • Controller checks site electrical conditions every second
  • Adjustments are made to the engine speed and configuration to maximize efficiency and minimize service to meet the power required
  • Load following with 100% turn down range

- Thermal Demand

  • Controller checks site electrical and thermal conditions every second
  • Adjustments are made to the engine speed and configuration to produce the heating required with minimal power

These modes can be set by:

  • Time of use
  • External Off/On from building management system or similar
  • Power exporting by secondary time of use
  • Grid connect including grid starting & leaner combustion for efficiency
  • Island Mode including rich burn for step load acceptance and responsiveness

Each operational mode has a particular purpose, however every one is designed to maximise the return for a particular business from their energy supply.

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Your knowledgeable CHP inverter generator specialists

If you have any questions regarding CHP inverter generators, or are considering the conversion to cogeneration for your business, get in contact with Inoplex today on 0448 307 282 or complete an online enquiry form. We are the leading professionals when it comes to cogeneration in Australia, so give us a call now.


Resources

Australian Government (Your Home: Batteries and Inverters) : http://www.yourhome.gov.au/energy/batteries-and-inverters

South Australia Government (Using Generators for back-up power): https://www.sa.gov.au/topics/energy-and-environment/using-electricity-and-gas-safely/using-generators-for-back-up-power

Aspen Systems Corporation (Combined Heat & Power) : https://www.energy.gov/sites/prod/files/2013/11/f4/chp_femp.pdf