Who is Apricus?

Apricus is the only distributor of evacuated tube technology in the Australian market place that owns its own manufacturing facility, has a team of dedicated in-house engineers working on product design and  innovation which has resulted in us supplying our product to over 30  countries around the world.

Apricus is not only committed to producing products that help reduce greenhouse gas emissions, we are also committed to helping educate society on how everyone can help reduce the negative impact of climate change.

ECOLOGIE SUPPLY DEPOT HAS BEEN A SUPPLIER OF EVACUATED TUBE SOLAR TECHNOLOGY FOR OVER 10 YEARS!

ALL PRICES QUOTED ARE BEFORE FEDERAL & STATE GOVERNMENT REBATES AND RENEWABLE ENERGY CERTIFICATE (REC) BUY-BACK

Federal Rebate is Currently $1,000.00 and NSW Rebate is $300.00 - Subject to terms and conditions.

Go to link at Government Rebate Pages

Understanding Hot Water

 
We all use hot water virtually everyday for washing, cleaning and in the winter even heating. Whether you are looking to invest in solar hot water or just wishing to learn more about solar heating this page provides you with a straight forward explanation of hot water systems.

 
How is Water Heated?

Water for domestic use is normally heated by electricity or a fuel burning boiler (gas/oil/diesel).

 

Electricity heats water by means of a resistance immersion element which is positioned inside the tank, directly contacting the water. As the electricity runs through the core of this element, it gets hot, and heats the water. This is SAFE, as the live electrical wires are not in contact with the water.

 

Electric resistance heating is very efficient, but is slow, taking normally around 3-4 hours to heat up a full tank of water to the target temperature. It also uses electricity, commonly produced from coal fired power plants, and so it be phased out and even banned in some regions, replaced with cleaner gas and of course SOLAR!

A fuel boiler heats the water by burning the gas/oil/diesel underneath a heat exchanger through which the water is circulated. In the case of a gas boosted hot water tank the heating may occur directly under the tank, similar to heating a pot of water on a gas stove.

How Much Energy is Needed?

An average household of 4-5 people will use around 300L of hot water per day. Given that the temperature of the hot water in the storage tank will normally be about 60ºC / 140ºF, the actual amount of hot water used at the tap could be 30% more, depending on how much cold water is mixed in and of course the cold water temperature.

The amount of hot water for such a household could easily be reduced by 25-40% by installing a low flow shower head. A tap flow rate of 8L/min is more than enough for a good strong enjoyable shower – if you have the right shower head!

The amount of energy required to heat the water in the tank to 60ºC / 140ºF will depend on how cold the water is to start with and this will change through the year.  Normally it will be within the range of 5ºC – 20ºC. So in the winter when the water is cold, more energy is required to achieve the same final temperature.

Here is how to calculate how much energy is needed:

 METRIC

To raise 1L by 1ºC you need 1 kcal of energy which = 1.16Wh of energy

Therefore: 300L from 10ºC to 60ºC you need 50 x 300 = 15,000 kcal = 17.4kWh

 What is Stratification?

 

Stratification refers to the layering of water in the tank according to its temperature. Hot water rises and so will always sit at the top of the tank above cooler water. This can be seen in the diagram above. The top half of the tank is hot water, after for example a couple of evening showers. This water will not mix with the cold that enters the bottom of the tank if turbulence has been correctly managed by the tank design.

Stratification is important to maintain because it allows a mains pressure storage tank to deliver up to 80-90% of its volume in hot water, before suddenly turning cold. If the water mixed, the temperature would gradually drop over time which is highly undesirable when having a shower.

 
Understanding Flow & Temperature

The hot water supplied from the storage tank, directly or through a gas booster is normally 60ºC / 140ºF. In order to ensure a safe temperature at the taps, a tempering valve (aka: anti-scold valve), will reduce the temperature to around 45oC. The water supplied to the tap is therefore a mixture of hot and cold. Additional cold may also need to be added if a cooler showering temperature is desired.

A flowrate of 9L/min  at the tap is NOT the same coming from the tank. Given the temperatures shown in the diagram below, the tank flowrate would only be 6L/min. This should be considered when sizing a tank given a known tap usage volume.

 

The amount the tank temperature increases with solar input depends on how much hot water remains in the top of the tank, and therefore how much “cold” volume is available for solar heating. This is why in tanks A and C, the temperature rise is moderate, as the full tank volume is being heated.

 
In tanks B and D, only the bottom half is being heated and therefore the temperature rise is much greater. In tank D, the bottom is first heated to 60ºC, then the entire contents is further heated up to 75ºC, at which point the controller turns off the pump to avoid further heating of the tank (depends on controller configuration).

The aim for any solar heating system should be to use all of the energy produced by the collector. Heating a tank full of cold water, as shown in A & C will result in more total heat production than for B & D, as the collector will be running cooler. Furthermore with a small volume of cold water to heat, the tank may even hit maximum temp (as shown in D), turning the pump off and potentially wasting good afternoon sunlight. For this reason BIG is generally BETTER when looking at storage tank sizing.

Having a dedicated solar tank is advantageous, and for this reason a gas post boost system is always preferable over an electric boosted tank system.