The system is neat and tidy in its installation, has met the client s requirements and creates an excellent model for other hybrid systems.

Transcription

1 1. SUMMARY An AC coupled 3.75kW solar grid-connect battery back-up system with as much Australian made content as possible was designed and installed. This had led to a very happy customer who has become a strong advocate for solar power. The system is neat and tidy in its installation, has met the client s requirements and creates an excellent model for other hybrid systems. The Hybrid PV System in the Garage with the House in the Background

2 2. THE SOLUTION a. What was the design brief from the client? The client requested a PV installation for their 3-bedroom home to cover their electricity bill. However, being a working family household with over 70% of their electricity usage at night, they knew they would require battery storage so they could store their solar power for use in the evenings. The low feed-in tariff available, combined with every increasing electricity prices meant the investment in battery storage would actually reduce their electricity bills by providing tariff optimisation, increasing self-consumption and providing added benefits such as battery back-up if there was to be a blackout. Due to the age of their home, the client also requested that an alternative location be found to mount the solar panels, as they knew their old, brittle roof tiles on the main house were overdue for some major maintenance. Additionally, the client specified the use of Australian products where possible as they wanted to support the local solar industry and minimise their carbon footprint. They had been purchasing Green Power from their electricity retailer for many years and were now ready to start generating their own solar power. They were seeking a long term economical and environmentally friendly solution. The client was inspired by a media article about a household solar grid battery system also installed by us for a family friend of the client. This was a Selectronic SP PRO MyGrid system with AC coupled Kaco inverter. b. How have you met the design brief? A 3.75kW solar array was mounted on the corrugated tin roof of the garage, at the rear of the property. As the garage was under 10 years old, the client was happy that the solar panels could be mounted there, rather than on the old brittle tile roof of the house. Since the garage roof was small, our design included the use of multiple roof aspects, mounting as many panels as possible on the north and west roofs. To maximise the panel count and fit with the roof s batten spacing, the panels were mounted in portrait for 8 on the west side and in landscape for 7 on the north side. Garage Roof Plan The client was surprised to learn about the world class solar technologies that are Australian made and was happy to choose 15 x Tindo Solar 250W polycrystalline PV panels and the Selectronic SP PRO interactive inverter charger both Australian made. The installation of micro-inverters would maximise the north and west roof areas with solar panels.

3 c. Where the design brief has not been met, what alternative solutions did you provide? There was no switchboard in the shed, so we supplied and installed a new switchboard and associated mains cabling from the house to the shed in underground conduits via landscaped garden beds and pathways. With the use of micro-inverters, the client was supplied with options for future upgrade to the system with 5 more panels on the east roof. With monitoring of loads by the SP PRO, increased load management by the client and future household usage pattern changes (with children growing older), the clients was sure they could reduce their electricity bill with a 3.75kW system for the moment. Cables Concealed Underground d. Detail any innovative and unique solutions. We had to install new timber framing to the shed roof in order to get all the correct mounting fixtures to install the PV modules in landscape to maximize the roof area. The use of micro-inverters is a new and unique solution in a battery back-up system, as many systems traditionally use a DC coupled MPPT charge controller or an AC coupled inverter like the Kaco as specified with the standard Selectronic MyGrid hybrid package. The Kaco would not have been suitable for this application as, at the time of install/design, the Kaco inverter models only had 1x MPPT, meaning it was limited for using multiple roof aspects. The micro-inverters were connected on the load-side of the SP PRO so they were able to provide solar charging with the SP PRO during a blackout, albeit simple single-stage charging in a simple form of frequency dependent power control (or frequency shifting).

4 3. SYSTEM DESIGN AND INSTALLATION Component list: QTY PARTS 15 Tindo Karra-250 DC polycrystalline solar module 250W 1 SPMC481-AU Selectronic SP PRO 5.0 kw 48V Interactive Inverter Charger 1 MG S6 Selectronic MyGrid Kit, 48V, 10kWh, Battery Capacity 16kWh, Battery Box 15 Enphase M S22 micro inverter 1 IPD 32 Amp, IP66 Ac Isolator 1 4C6FD(WE) Switchboard Surface Mounting-Full DIN Rail 12 Module - 36 pole busbar 1 Formply 2400x 1200mm - [control board] SAFETY SIGNAGE 1 Safety Sign: No Entry Authorised Personnel Only 1 Safety Sign: Electrolyte Burns 1 Safety Sign: Emergency Shutdown Procedure + Battery SC Current Sign 1 Safety Sign: Spark Hazard 1 Safety Signs (Grid Connect Package) Manuals and Safety Signs

5 Schematic

6 PV Panels on the Garage Roof with a View Inside

7 The My-Grid System inside the Garage

8 4. OUTCOMES AND BENEFITS a. Was the client satisfied with the solution? The client is very happy with his system. Following is his experience in his own words: We had wanted to do our bit to reduce CO2 emissions for some time but with the reduction in feed-in tariffs it had become uneconomic. As all our family is out during the day our energy consumption did not line up with the peak solar collection times of the day. We heard about a hybrid solar system via a contact and it warranted further investigation. We approached [the solar company] with our issues and they presented a very thorough proposal. We had a number of issues to address including: A desire to use our corrugated iron roof on the garage rather than our old double storey fragile tile roof on the house. Restricted northerly aspect roof space on the garage but more space facing westerly. Our desire to store the power generated during the day to use during our peak evening period. A preference for high quality Australian panels rather than cheaper Chinese panels. Our desire to run the cabling underground rather than overhead complicated by a large paved area between our house and garage. [The system designer] worked through these issues and proposed a system utilising Australian made Tindo panels with micro-invertors on both northerly and westerly aspects of our garage roof. The use of the micro-invertors enabled us to have each panel working to its maximum level according to the amount of radiation falling on it rather than what the worst panel was collecting. Within the garage is the battery storage and Seletronic My-Grid control system. The installers completed a very neat and compact job in the garage and on the roof. Their underground cabling hides all evidence of the huge amount of work which went in to laying the cables. [The installer] and [the solar company] provided valuable assistance in getting all the approvals, final signing off and paperwork completed. There is still some final tweaking of the programming of our energy use/storage program but we have been thrilled to see how much energy we have captured and thus done our bit to reduce Australia s greenhouse emissions. Ref: Client, 31/8/15

9 b. Were there any stand out social and environmental benefits? Every PV system installed furthers the environmental and social benefits to both individuals and the wider community. This system helps pave the way for the next stage in the solar panel market and in the forthcoming revolution in battery storage. From little things big things grow. c. Were there any unexpected or additional outcomes? It s good when clients understand how their systems work and where they strive to greater energy efficiency. This particular client has really engaged in these activities and we are keen to support him. d. What were the economic benefits? The customer has a relatively high power load, much of which is in the evening. The investment in this hybrid system allows the off-setting of electricity generated during the day for use in the evening which is better value for the customer then selling the power at the current feed-in tariff rate. The customer recognises that it will be a long term investment but better than leaving money in the bank or purchasing something else. He was prepared to invest in quality equipment and a quality installation. e. How does it contribute to the Australian solar industry? Our industry and the wider community expects a significant shift towards onsite energy storage in the near future. This bespoke arrangement sets the example of how systems can not only work for the customer but how they can be designed around a client s particular needs and requirements. It may be that in the future hybrid kit systems are wheeled into many sites but there will always be a need for specialist design skills and quality installations for some sites. This system will become a case study which will help demonstrate the viability and practicality of hybrid systems to a keen though naturally initially cautious public. We see a significant future in hybrid systems in Australia and this system raises the benchmark. The other contribution is that the significant components are Australian designed and made thus supporting the manufacturing side of our industry.