FAQ – SOLAR HOT WATER
What are the different types of Solar Hot Water Systems Available?
There are 3 main types of Solar Hot Water systems available on the Australian market.
These are:
- Flat Plate Solar collectors
- Evacuated Tubes
- Heat Pumps
Flat Plate Solar Collectors
These can be roof mounted with a tank or a split system with the solar collector on the roof and the tank on the ground. Flat plate collectors operate using copper pipes which are fed through a glass plated collector, this is either connected to a tank on the roof or alternatively on the ground. The hot water is then thermo-siphoned in and out of the tank which heats the water.
Evacuated Tube Solar Collectors
Evacuated Tube Solar hot water systems use a glass tube with an internal vacuum and copper pipes which run through the middle. The copper pipes are connected to a shared manifold which is then connected to a slow flow circulation pump that pumps water to a storage tank below.
Heat Pumps
Heat pumps have been on the market for over 15years. Its often described by many as an air-conditioner in reverse. They operate because air from outside is drawn into the heat pump system into an evaporator containing a special refrigerant called R134a. The refrigerant which is far cooler than the warm air which has been drawn into the system turns the refrigerant from a liquid into a gas inside the heat pump’s piping. Then a compressor pumps the gas through a tiny valve which then compresses it and in turn generates a high amount of heat. Finally, a heat exchanger transfers the heat from the heated refrigerant gas pipes to a tank where water is stored.
What are the green benefits of installing solar hot water?
Hot water accounts for about 25%-35% for the average family household electricity bills depending upon tariffs and type of hot water systems, for some households it can be more. By replacing your old electric hot water system you can be saving the environment from 3-4tonnes of green house gas emissions per year. The federal government and some state governments realize the importance of solar hot water and have provided generous rebates and renewable energy certificates.
FAQ – SOLAR POOL HEATING.
How does solar pool heating work?
Solar pool heating works by using the sun’s energy and is the most effective and efficient way of heating your swimming pool. A controller is automatically switched on and off when the direct solar gain is sufficient to be greater than the actual pool temperature as a booster pump then is engaged to circulate the pool water through absorber matting on the roof. The water is then warmed and returned to the pool. This process is continually repeated until the thermal comfort temperature which is predetermined by the controller has been reached.
What temperatures can I expect with Solar Pool heating?
This depends upon the orientation and area of the absorber and the outdoor temperature. In Qld it would not be uncommon to have temperatures of approximately 26-27 degrees for nine months of the year and slightly less for southern states.
How long can I swim in my pool with Solar Pool Heating?
In Queensland and the Northern states, solar pool heating should give you swimming all year round.In the southern states, solar pool heating should double the available swimming months per year, it will also extend the hours that you can swim from early morning to late evening.
What angle should my pool heating blanket be set at?
There are two angles to consider: North-South direction and inclination up from horizontal.For best performance, face the solar panel generally North at an inclination of 15 to 30 degrees up from horizontal. This will point the face of the panel nearly directly at the sun.Don’t stress over the exact angle, you should be fine as long as it’s close.
In terms of angle, I have read that you should tilt the panel at an angle equal to your latitude geographically. So, LA is 34 degrees LAT, therefore tilt the panel 34 degrees for year round installation. If possible it should be tilted accordingly for seasons. But for solar pool heating brisbane the Lat is approx 27 degrees.
I found a web site with the acronym RSPEC (Reduce Swimming Pool Energy Costs) that suggests the following:
The collectors should (ideally) face due north and should be angled based upon your latitude. For heating in the summer months subtract 10-15 degrees from your latitude. For heating in the winter months add 10-15 degrees to your latitude and for year round heating install at your latitude.
FAQ – SOLAR POWER
What is PV?
PV stands for photo voltaic which is a technology that converts light energy into DC or direct current electricity. The reason this is so unique or superior to other forms of energy production is that PV or Solar technology uses no fossil fuels resulting in no pollution.
How does Photo Voltaic (PV) or Solar Power work?
PV Power operates on the principle that electricity will flow between two semiconductors (typically crystalline silicon) when they are put in contact with each other and exposed to light. By linking a number of these ‘cells’ into a Panel (also called a Module), a useful flow of electricity can be generated. Any number of Solar Panels can be used in a system, providing a very flexible approach to power generation.
How long have solar panels been around?
The first ever solar cells were produced in the 1880’s. The mono panel that we see today has evolved from mono panels produced in the 1950’s.
What is the difference between solar power and solar hot water?
A solar power system uses light and silicon cells to produce electricity which is used to power your home whilst solar hot water uses the sun’s heat to heat your hot water. A large percentage of consumers still mix up the two.
What variables affect the amount of solar energy created?
The intensity of the solar radiation (strength) depends upon a number of factors. The most obvious is the orientation of the solar array. In the southern hemisphere solar panels should face North. The time of the year and the time of the day are other obvious barriers to optimum solar radiation or solar gain. Cloud cover and shading are other factors to be considered as well as dust and water vapour.
What is a Grid Connected Solar Power System?
A grid connected solar system consists of an array of panels connected to an inverter which delivers power via a bi-directional meter to the home then the surplus is delivered to the residential power grid. A grid connected system requires no batteries like standard off-grid systems.
What is an off-grid solar power system?
These systems are commonly used on farms or remote coastal areas where access to generators or the power grid is not feasible or proves to expensive. These are basically designed to operate independently of the electricity grid. The most basic type of system is called the direct coupled stand alone system. The DC output of the solar module is connected to a DC load without batteries to store the energy. Therefore, since there is no electrical energy storage (batteries) in direct coupled systems, the load only operates in daylight hours. It may power such devices such as fans, pumps or hot water systems.
However, there is another off grid system that stores the energy from the solar array in the form of batteries. This is a more common and versatile system because the stored energy from the batteries can be used at night in the form of AC power which has been converted with the help of an inverter which converts the DC to AC power.
Which Direction should my panels face?
To receive ultimate solar gain or direct solar radiation so the panel’s work at their most efficient, it’s best to have the sun’s rays hit the panels at 90 degrees. Therefore, this means that because Australia is in the Southern hemisphere its best to have your solar panel array facing north to receive this optimum solar gain. Solar will still operate on west and east facing roof space but be less efficient.
What are the different types of solar panels?
There are 4 main types of solar panels which are available in Australia today.
These are:
- Mono Crystalline
- Poly Crystalline
- String Ribbon
- Amorphous/Thin Film
- MONO CRYSTALLINE…
These panels have been around for the longest and have been proven to go the distance. They have the highest efficiency of any panels on the market. The efficiencies can be anyway from 10-20%. They can however be the most expensive. Some typical mono crystalline panels include: Suntec, BP Mono, Ceeg, Trina, Epolly, Sunpower & Sharp.
- POLY CRYSTALINE…
These panels are made from multi-crystalline which is easier to make than the mono panels. They are very similar to mono, yet they are not as efficient. They have an efficiency of about 10-11% per panel.
- STRING RIBBON…
These panels use a relatively new technology fabricating technique which involves dragging a set of metal banding through a film of molten silicon and it creates a ribbon of silicon that does not need to be cut up any further. These panels are not as efficient as the previous mono or poly panels.
- AMORPHOUS/THIN FILM
This is a relatively new technology. The panels are produced by spraying silicon onto a base as a thin film. It is rather inefficient for its size. So typically you will need much more roof space to achieve the same efficiency as the mono or poly panel. Amorphous panels typically produce about 5-7% efficiency per panel.
Is my house or building suitable for solar power?
There are a number of variables that determine a building’s suitability for solar power. Unfortunately some homes are not suitable for solar for a number of reasons. These include:
- Inadequate north facing roof or limited east or west facing roof space
- Too much shade from neighboring properties
- Too much shade from protected vegetation.
- Does your electricity bill justify the outlay for solar power?
What will happen to my grid connected system in a blackout?
Your inverter will shut itself off in the event of a blackout. This is to protect your home from the complications associated with “brown outs” and subsequently preventing back feeding to the grid.
What if I need to re-roof my house after the panels have been installed?
Most solar companies will offer a service (sometimes for free – depending upon the size of the system) to remove and reinstall the system once the roof has been replaced or repaired. Remember, you should not try this yourself. It’s important for a qualified licensed accredited electrician to do this.
What angle should my roof be?
Anywhere between 10 & 45 degrees, however, somewhere between 20 & 30 degrees is ideal.
What if I have a flat roof?
Most companies get around this by providing low or high tilts that direct the panels to their optimum position.
Is there a basic checklist that I need to determine whether my home is suitable for solar?
There are so many variables and different building setups that it’s hard to give a static list of requirements for solar systems. All of our suppliers are experienced in coming up with alternatives if your property does not comply with a standard list of attributes. However, a basic list of the main features required is listed below.
- Do you own the roof space?
- Does the roof have at least 10 sqm of unshaded roof space?
- Is the roof pitched between 10 & 45 degrees? (no great deal if it isn’t)
- Does the roof face north?
- How many stories is your home?
- What material is your roof made from?
I heard I can make money out of my solar, Is this True?
Yes, this is certainly possible with the availability of different state tarrifs. These are either Net Feed in Tariffs or Gross Feed in Tarriffs. It basically means that if your system produces more electricity than you use you will be eleigible for credits or cash payments from your electricity retailer. How much you get back depends upon the electricity useage in your home and the size and efficiency of your solar power system.
How Big a Solar Power system will I need?
That depends on a couple of key points,the first being your budget and the next being the amount of electricity your household/business uses per day.
A rough guide can be found below based on the N.S.W gross feed in Tarrif of 60cents per kwh: (this is an estimate and will vary depending upon your individual situation and needs) Mysolarprice.com.au accepts no responsibility on any future financial viability of solar power generation systems purchased based on these assumptions.
| QUATERLY BILL | SYSTEM SIZEBASED ON N.S.W GROSS FEED IN TARIFF 60C/KWHAND NORTH FACING ROOF WITH NO SHADE | NEW QUATERLY BILL (BASED ON 10% DAILY USE) | PAYBACK PERIOD IN YEARS | RETURN ON INVESTMENT |
| $100 | 1.5KW | $252.00 CR | 3.2 YEARS | 32% |
| $200 | 1.5KW | $181.00CR | 2.9 YEARS | 35% |
| $300 | 1.5KW | $109.00CR | 2.7 YEARS | 37% |
| $400 | 1.5KW | $ 33.00CR | 2.6 YEARS | 38% |
| $500 | 2.2KW | $127.00CR | 3.7 YEARS | 27% |
| $600 | 2.2KW | $ 40.00CR | 3.7YEARS | 27% |
| $700 | 2.2KW | $ 60.00 DB | 3.7YEARS | 27% |
