FAQ: Tractile Solar Roof Tiles

What is a typical Tractile roof?

A typical house in Australia will require approximately 250 square metres of roofing, including a 5kWp solar PV system for electricity covering 30 square metres, and solar pool heating covering 20 square metres. To meet these needs the following Tractile roofing products will be used:

  • 50 Eclipse Solar tiles (5kWp), weighing 32 kg/sqm, to clad 30 sqm roof and will generate on average 20kWh of electricity and 350 litres of pre-heated hot water per day
  • 42 Eclipse Thermo tiles, weighing 32 kg/sqm, to clad 25 sqm roof, and will generate on average 300 litres of 60 to 70 degrees Celsius hot water per day
  • 330 Eclipse roof tiles, weighing 12 kg per sqm, to cover 195 sqm roof area
  • Various other Tractile Eclipse roof components like Tractile battens, Eclipse ridge, hip and barge tiles, and end-caps

 

What are the technical benefits of combining solar photovoltaics and solar thermal hot water in one tile?

Integrating photovoltaics into the roof tile delivers an improved look of the roof, and also delivers a number of functional benefits:

  • Increasing the electricity produced by the photovoltaic modules as the cooling effect reduces thermal resistance;
  • Cooling the photovoltaic cells reducing degradation due to long-term heat exposure resulting in longer lasting efficiency;
  • Photovoltaic cells are circa 20% efficient, so rather than waste the remaining 80% we use the thermal to harvest more of this energy, increasing efficiency per square metre;
  • Heated water is a store of energy and in a typical household circa 40% of energy consumption is used to heat water;
  • Reducing heat load on the house as heat is captured in the skin of the building and piped away so less air conditioning is needed for cooling.

 

How are Tractile Solar Roof Tiles connected?

The tiles are installed on the roof in accordance with the Tractile ‘hook & batten’ ­fixing system. Adjoining tiles connect to each other using standard solar electrical cables and MC4 connectors, and SharkBite® plumbing connections. The solar photovoltaic modules are connected in series and can be used with micro-inverters or standard string inverters. The plumbing connections between tiles use a Sharkbite® push-­fit connector and Tractile copper ‘U’ pipe, and tiles are connected horizontally in rows with ’T’ junctions at the end of each row connecting to either an inlet or outlet riser and equal flow manifold. A pump circulates fluid through the tile array when the roof temperature is hotter than the tank temperature, with a heat exchanger used at ground level to transfer the heat to the required use.

 

What precautions are taken to avoid leaks?

Tractile Solar Roof Tiles are designed to withstand up to 1000 kPa water pressure with an operating pressure less than 100kPa. Sharkbite® fittings have a 25-year warranty. During installation each row of connections is pressure tested before installing the next row. As the plumbing connections are located on the upper surface of the tile, in the unlikely event of a leak occurring, any leak will drain to the external surface of the roof, both identifying the location, and preventing an internal water leak to the house.

 

Do you need to connect the hot water channels in the tiles?

No. However it is recommended for warmer climates to cool the photovoltaic module which increases the electricity produced.

 

Do Tractile solar roof tiles work in winter and in freezing conditions?

Yes. Tractile Solar roof tiles can operate in temperatures down to -40’C. For freezing Zones the circulating fluid must contain antifreeze. The solar tiles will not produce heated water in cold conditions.

 

What are the financial benefits of a Tractile Solar Roof and what is the payback period?

The returns from investing in a Tractile Solar Roof comprise both quantitative and qualitative returns. Quantitative returns are most directly impacted by factors including: system size and cost, rebates and incentives, financing terms, and cost of alternate energy. Qualitative returns deliver value, such as: energy independence and being able to live off-grid, safety in extreme weather events, enjoyment of the look and feel of the home, less maintenance, and future resale value. Good design will maximise the financial returns.

As a guide, for a typical house the savings on energy costs alone provide payback periods of 5-7 years for residential properties generating power for domestic consumption (no feedback to grid) and 3-4 years for residential properties generating power for domestic consumption and to charge an electric car.

After the payback period is complete the Tractile Solar Roof provides free energy.

 

Can Tractile Solar Roof Tiles be connected to Battery Energy Storage Systems?

Yes. Tractile can be connected to any battery energy storage system.

 

What is difference between kWp and kWh?

Electricity generation:

kWp in solar PV defines the peak (maximum) capacity of a solar PV system under standard test conditions (i.e. at 25 degrees Celsius, 1000 Watt per square meter).

The generation of electricity is measured in kWh. For example, if a 2 kWp solar PV system operates for 1 hour at peak capacity the system has generated 2kWh. The actual performance of solar PV system (in kWh) depends on location, orientation, weather conditions and solar irradiance.

Electricity consumption:

kWp means maximum draw a device has. kWh means actual electricity used. For example: a 2000 Watt (2 kWp) water kettle consumes 2 kWh if it is used for 1 hour. If the water boils in 3 minutes and kettle switches off then the electricity consumption has been 0.1 kWh; and, a 2 kWp air-conditioner cycles 30% of the time, so after 5 hours the electricity consumption has been 2 x 30% x 5 = 3 kWh.

 

Can a damaged Tractile Solar Roof Tile be replaced?

The Tractile Eclipse Solar Roof Tiles use high quality PV cells and junction boxes. Damage to the Tractile product is most likely to be cause by events such as a misdirected  golf-ball, vandalism, falling tree, etc. Damaged tile(s) can be replaced by removing the ridge tile and upper rows, or the barge or hip tile and neighbouring tiles.

 

What is the best roof orientation for Solar?

In Australia the best orientation is North facing on a tilt angle between 20 – 27 degrees (Sydney 24 degrees). Systems can be split to face East to capture more energy in the morning and West to capture more energy in the afternoon. The benefits very much depend on when power is consumed.

 

Where is the Tractile roof made?

The Tractile roof is made in our manufacturing facility in Malaysia. The Solar PV cells are sourced from high-quality cell manufacturers and laminated in PV modules to our custom design. The PV modules are assembled in the Eclipse solar tile chassis in Malaysia.

 

What maintenance does a Tractile roof require?

A Tractile roof is resistant to corrosion. The tiles and battens interlock hence no roof penetrating screws or nails are required. The solar PV and hot water are integrated in the roof, avoiding roof penetrations from brackets. All wiring and plumbing is under the roof, again avoiding roof penetrations, and protected from wind, pests and vandalism.

Minimal maintenance is required for a Tractile roof. For low pitched roofs, a yearly inspection of sealants and flexible lashings is required and cleaning dust buildup from the solar PV tiles during long, dry periods will ensure the performance integrity.

 

Can Tractile withstand hailstorms?

Yes. Tractile is designed for strength. The non-solar tiles can withstand 65mm hailstones (tennis ball sized). The Eclipse solar PV glass can withstand 30mm hailstones, equal to conventional solar PV panels.

 

Can Tractile be installed in cyclonic areas?

Yes. Tractile is designed for strength and its batten-hook system can withstand category 5 cyclones (wind speeds over 280 km/hour).

 

Can Tractile be installed in bushfire areas?

Yes. Tractile has BAL-40 certification. This is the highest rating for residential buildings in bushfire prone areas.

 

What is the weight of a Tractile roof?

The Tractile roof weights 12kg per square meter for non-solar tiles and 32kg per square meter for the solar tiles. An average quality metal sheet roof (Colorbond) weights 10 kg per square meter and concrete tiles roof weights 35kg to 50kg per square meter.

 

Can a Tractile Solar Roof be walked on?

Yes. Tractile is designed for strength and can withstand 250kg point loading. 250kg is equal to 2 tradesmen standing with their toolboxes on a single tile.

Can Tractile withstand corrosive environments i.e. coastal conditions?

Yes. Tractile is made from composite materials that are resistant to corrosion.