Stand Alone Solar Power System Design
When designing an off grid power system, it is crucial that we determine the size and type of loads that require powering and when they require power. Variation in load demands need to be evaluated, including seasonal differences, day vs night loads, heat and cooling systems and in many off grid homes, water pumping requirements.
Off Grid Solar Power Systems are generally designed for worse case condition, ie, Winter Periods where solar radiation drops to more than half of average summer output. Batteries play an important roll in providing power autonomy, and can be scaled up to eliminate the need for a backup generator. Generally, we design systems for 2 – 4 days of autonomy.
An average sized off grid power system capable of supply loads to a modern home, will consist of 5-10kWp of solar PV panels, between 15 – 40kWh of available battery energy, and an inverter charger which can discharge between 10 – 20kWp of power.
Smaller off grid power systems can be designed for Mobile Homes, Yachts, Sheds and Villages Dwellings for as little as a few thousand dollars. Please enquire for further details.
Home Efficiency and Design Principals in relation to an Off Grid Power System
Home Design and Appliance Efficiency play a critical roll in determining the size and characteristics of the stand alone power system. Generally, the heating and cooling of a home will determine the cost and size of an off grid power system, so it is imperative that careful consideration be given to home climate control. The Green Power Company recommend the use of evaporative cooling systems in summer (for non-humid conditions) and heat pump/ fire boosted underfloor hydronic heating systems for winter.
Back Up Generators
Stand Alone Power Systems do not have the luxury of mains power backup, so a backup generator is generally required for the worst days of the year. The supplied generator should have Two Wire Auto-start functionality, and have an output peak equal to the combined active loads of the property.
Back Up Power Generators are wired to the inverter charger for automatic startup when solar input is lacking and the available battery power is exhausted. GreenPowerCo can supply and install recommended auto-start generators upon request.
Hybrid and UPS Systems
A Hybrid Solar Energy System usually refers to a solar pv and battery storage with mains grid backup. Hybrid systems are becoming increasingly popular, as battery prices continue to drop and feed in tariffs decline.
There are many types of hybrid inverters, which generally convert solar direct current (DC) to Alternating Current (AC) while being able to intelligently charge and discharge power from the batteries when required. Many Hybrid Inverters have the ability to charge batteries from the grid, which can be useful for UPS systems, as well as using off peak power for use at peak periods.
With the advancement of quality low cost Lithium Battery Technology, most of our Hybrid systems are installed with Lithium Battery banks which are more compact and offer greater cycle life than conventional lead acid type batteries.
Hybrid System Upgrade
Most Installed Solar Power Systems, can be Upgraded to include batteries for a Hybrid Solution. In most cases, the existing grid connect inverter is replaced entirely with a solar hybrid inverter, coupled with a battery bank, however, a quality grid inverter can be coupled with an inverter charger to create a hybrid power system.
Uninterrupted Power Supply (UPS)
A Hybrid System can be effectively used as an Uninterrupted Power Supply (UPS) providing power security in case of main grid failure. These Hybrid Systems require fully charged batteries in case of power outage and can be installed without a solar power system, using the main grid as the source of battery charging. UPS systems, both solar and mains grid connected are effectively used in commercial applications.
Hybrid PowerSystems also play an important roll in solar system stability by storing excess solar generation into battery banks for use at night. A well designed solar battery hybrid system will increase savings and create greater power security and independence. Read More