The Apricus solar collector is designed to be used with pressure up to 8 bar/116psi.
This means it is compatible with all low pressure, and most mains pressure domestic hot water systems.
In closed loop or sealed (dead water) thermal store systems an expansion vessel is often used to prevent pressure buildup as the water expands.
A pressure release valve should also be used as a safety backup.
In areas where freezing is not of concern, open loop systems are often used.
Open-loop systems are also appropriate for cold regions when used in combination with a Delta-T controller that incorporates a freeze protection feature.
Closed loop systems usually incorporate the use of a heat exchanger, either inside or outside the hot water storage tank.
Apricus solar collector are suitable for both open or closed systems, as long as pressure, heat and freezing are controlled.
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The Apricus Solar Collector or Solar Water Heater is a device that absorbs thermal energy from the sun and converts it into usable heat.
The heat is normally absorbed by water, or a freeze resistant water mix, which can then be used to supplement hot water heating, space heating and even space cooling via use of an absorption chiller or dessicant cooler technology.
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Evacuated tubes are the absorber of the solar water heater. They absorb solar energy converting it into heat for use in water heating.
Evacuated tubes have already been used for years in Germany, Canada, China and the UK. There are several types of evacuated tubes in use in the solar industry.
Apricus collectors use the most common “twin-glass tube”. This type of tube is chosen for its reliability, performance and low manufacturing cost.
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Evacuated tube technology was first developed in Australia at the University of Sydney — some 40 years ago.
More recent developments have improved their technical efficiency and they are now rapidly invading the solar hot water market worldwide as Chinese manufacturers have managed to bring down the manufacturing costs to very competitive levels.
So now, at long last, we have a state-of-the-art solar hot water system that is very affordable. They have also stood the test of time, systems installed 40 years ago are still going without maintenance.
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Absolutely. Tasmania has the same latitude as northern Italy and well within the latitude band in which solar energy gain is viable and profitable.
Solar hot water systems are in widespread use in much less favourable climatic conditions — such as Northern Europe and Alaska.
The development of the evacuated tube solar technology has enabled solar hot water to become even far more financially attractive in cooler climates such as ours.
Most Tasmanian homes are suitable for solar energy.
All you require is an unshaded roof facing roughly north (any aspect between north west and north east will give good results). Even an Easterly facing roof can work without too much loss of efficiency.
The solar collector should be mostly unshaded by large trees and buildings, especially between the hours of 9 am to 3 pm.
If your roof aspect is very limited, there are always solutions. An offset frame can be installed, or in some cases, it is possible to face part of the system in one direction, part in another.
(Some houses do get too much shade for adequate solar gain. If your house has limited solar access for some reason, then consider installing a hot water system driven by a heat pump technology. These are extremely efficient and will reduce your hot water bills by a similar amount.)
Here you need to consider a number of factors, such as the size of your house (how many rooms?), the size of your household (how many residents?), your lifestyle choices (long hot showers?) and your budget.
You also need to consider any likely changes to any of these factors in future years (growing families, possible sale of house, children leaving home etc).
Household hot water consumption can vary from 70 litres per day to several hundred, depending on usage patterns.
If you under-invest, you are likely to need excessive electric/gas boosting which will end up costing you more than your saving in capital cost.
If you over-invest, you may produce more solar heat than you can use up and will also increase your payback period.
The difference in price between a 20-tube system and a 30-tube system is approximately $300, so if there is doubt and you can afford it, it is generally better to opt for the larger system.
In Tasmanian conditions for a typical household (3 people or more) it is generally recommended to install a 30-tube system.
Remember that solar hot water cylinders are normally designed to store water for use over 2 days, rather than one, thus allowing you hot water even if the following day is cloudy.
This largely depends on the size of the solar system you install. You can roughly work on the basis of 10 litres of water storage for each solar tube that you install.
For Tasmanian conditions, we recommend a minimum cylinder size of 250 litres if you install a smaller (20-tube) solar system and 315 litres if you install a 30 or 40-tube system.
If you fit a smaller cylinder, you may have hotter water, but less of it, and you will lose some system efficiency.
If retrofitting to an existing smaller cylinder (say 170 litres) you can expect some loss of efficiency. However, this is not advisable if you install a larger solar system because you will waste much of your solar gain.
A larger cylinder will enable you to store more heat during periods of inclement weather and will enable you to maxi mise the efficiency and solar gain from your system.
In Summer months you can expect most of your hot water supply to come from the sun (about half the year).
But the technology works well in cooler climates too, and you will get significant heat even on cooler days that have light cloud cover, so expect solar gain throughout the year.
While evacuated tube technology works efficiently even on very cold sunny days, keep in mind that the solar intensity is 5 times less in Winter than in Summer.
For this reason, it is best to optimise your system for Winter conditions by tilting the solar tubes to a slope of 45 degrees. By doing this you will get maximum efficiency in Winter whilst avoiding excessive heat wastage in Summer.
Low cost stainless steel frames are available if your roof is not steep enough.
(In Summer, you can expect to get 25kWh of heat per day from a 30tube array, whereas in July you can expect 5kWh per day on average. Even in the winter, it is possible to preheat the water to 40C or more if the sun comes out. The booster will then take it up to your desired temperature.)
By way of example — a 270litre cylinder of water heated to 65°C will hold around 14.3 kwh of energy storage. (This is equivalent to running a 1 kilowatt heater for 14.3 hours.)
The Apricus system will boost the cylinder temperature to 80°C, so a fully charged hot water cylinder will give you ample heat capacity for a typical home.