architecture tips

There are more than one reason to use an off-grid system and often a mixed system allowing you to use the grid as a backup is an appropriate implementation. When moving towards a more sustainable office or home environment you are likely to employ alternative energy generation techniques which may commonly reach from Solar or Wind to Propane Combustion Engines. Following is a brief outline of the main topologies:

Tri-Generation
There is the tri-generation environment where typically Grid-Power, Propane Generators and Solar and/or Wind are all feeding the same system. This is for mission critical applications where power will always be available at the lowest cost and as much renewable power as generated is used.

In a tri-generation environment AC is normally the distribution method, this may change in the future to DC at least for the lighting system, computer backup and air-conditioning.

On-Grid System
An On-Grid System is based on Solar or PV Generators feeding the grid via a separate meter and a DC to AC converter, the energy supplied to the grid is credited to your account. The energy used by you from the grid is charged as usual. There is no backup to the grid, if the grid fails there is no energy.

Grid Assist
A Grid Assist System is typically based on Solar and Wind Generation coupled with the grid charging the storage batteries when insufficient wind or sunlight is available.

Off-Grid System
An off grid system can be Solar and Wind Generation only or coupled with a Diesel, Gasoline or Propane Generator to allow seamless energy during spells of no wind or insufficient sunlight but no connection to the grid. The supplementary generator would use electronics to automatically start if batteries need charging and no solar or wind power is available.

Generation using Combustion Engines
In 2008 propane was officially declared a renewable energy receiving the same federal assistance as other renewable programs such as wind and solar. As propane is a by-product of dormant and active oil wells it was available in abundance and rather than burning it off at the well or the raffinery it can be put to good use for fuel in vehicles with combustion engines, heating or electrical energy generation using turbines, piston or Wankel combustion engines. However, the most cost effective form of energy is Natural Gas where it is available as Propane has now reached the same prices as any other form of gas or petroleum that can be put into a car.

Electricity Generation using Solar PV Panels
Photo Voltaic (PV) panels convert light into electricity and are best suited in regions with a fair amount of clear skies their efficiency ranges from 5..10% of light energy converted to electricity. The only maintenance required is to remove dust from the panels from time to time especially in dry weather conditions. The cleaning frequency ranges from 3 days in Texas and Arizona to a weak or two in less dusty areas.

PV Generation requires a storage medium, mainly batteries. Various voltages can be applied but the safest voltage is 48V while optimizing the conductor size. Lower voltages would require larger conductors and are therefore more expensive, higher voltages are more dangerous as High Voltage DC is more dangerous in case of a person touching the terminals.

Klaus Bollmann is a 30 year veteran in energy conservation, resource saving innovative products for a sustainable environment. Click the link If you are interested in Ringdale DC Systems high performance 48V DC products or ActiveLED 48V DC capable lighting systems.

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