In ‘Solar hot water and heat pumps’ Category

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Can’t afford a solar hot water system? Try a retrofit kit

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Dave Wakeham investigated several solar hot water options before finding that a retrofit kit was the best solution.

I couldn’t help but think there was going to be a big rise in the price of electricity, and as we are on a fixed income (both on disability pensions), I was worried that it was going to blow our budget. I was sure there was a way to beat this.

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Our biggest electricity use is an electric hot water system, so I decided to start there. The cost of a close-coupled solar hot water system was about $5,500. Things are quite expensive in North Queensland but I thought this was exorbitant and beyond my means. There was additional expense because my house has an aluminum roof and needed beefing up to take the weight of a close-coupled system with a collector panel and tank.

The plumber said it was not feasible to remove the large sheets of aluminum to add the timber, as it is almost impossible to put them back due to the age of the roof. He suggested that I build a leanto off the side of the house and use the solar collector as a roof for it.

I deliberated for some time (my wife says I normally do), and when the next ReNew magazine arrived I was quite surprised to see there was an in-depth article about solar hot water systems. The article started me thinking that maybe I don’t need a full system. I already have a perfectly good, well-insulated 125 litre electric hot water tank with a good element.

A retrofit seemed to be the way to go. I read about a five-way valve, a 10 watt PV panel, 12 volt pump and a solar collector and fittings. I thought this may not be as expensive as a whole system if I could find the items locally. I investigated and found that people would rather sell me a whole system. Also, a retrofit would not be covered with a warranty and did not attract a government subsidy. Back to the drawing board.

Buying a kit

I then read about a Solar-Mio/Metal Dynamics retrofit kit made by Albury Consolidated Industries. After a few emails to establish exactly what is in the retrofit kit, we decided on a SM-Tops1 squat panel PV pump system with five way fitting at a price that included freight to Townsville. We decided that one panel would be enough as we are a two person household and only use hot water to shower each day. I was extremely happy with the price as it was less than a third of the price of a leading brand close coupled system that sold in Townsville.

Read the full article in ReNew 103

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Solar hot water buyers guide

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If your old hot water system has given up the ghost, maybe it’s time to go solar. We show you how solar water heaters and heat pumps work,  what’s available and how to choose the one to best suit your needs.

There are many reasons to choose a solar hot water system or heat pump over a  conventional gas or electric water heater. With the rapid increase of energy prices in recent months, a solar or heat pump water heater can greatly reduce energy bills. Up to 30 per cent of household energy is used just to heat water, so anything that can reduce this energy use will save you a lot of money.

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Another important benefit of such a system is that of greenhouse gas emission reduction. A solar water heater or heat pump can reduce the greenhouse emissions of an average family by as much as four tonnes of CO2 per year—the equivalent of taking a car off the road!

Most state governments  have recognised the advantages of solar and heat pump water heaters and offer incentives in the form of rebates. These vary from state to state, but can save you a great deal on the cost of a new water heater, making them more economically viable. The initial purchase price will probably still be higher than a similarly sized conventional water heater but the savings made in running costs will pay for this difference in less than 10 years—in as few as four years in some cases.

How does it work?

A solar hot water system usually consists of a hot water storage tank connected via pipework to solar collector panels. These collector panels are placed on a north facing roof and at an angle of no less than 15° to the horizontal. The tank can either be situated immediately above the panels on the roof (called a close coupled system), above and a small distance away from the panels within the roof cavity, or at ground level (a split system), in which case a pump and controller is required to circulate water through the panels.

As the sun shines on the collector panel(s) the water in the pipes inside the collectors becomes hot. This heated water rises through the panel and out through a pipe to the insulated storage tank. Cooler water from the bottom of the storage tank enters the panel at the bottom to replace the warmer water.

This is called the thermosyphon process, requires no pumps or other devices and is very simple and effective. However, it does require that the storage tank be situated above the collector panels. The collector panel is the driving force for the circulation, so due care must be taken with its mounting and orientation to get maximum benefit from it.

If the tank cannot be located above the collectors, a pump and a differential temperature controller must be used to provide water circulation. The controller also turns the pump on when the temperature drops to 5°C as a frost protection function.

Some systems don’t heat the water directly but instead heat a fluid similar to antifreeze used in vehicle cooling systems. This fluid flows through a closed loop system (through thermosyphon or pump action) and transfers the collected heat to the water in the tank via a heat exchanger.

There are pros and cons with each system. Close coupled systems require the roof support the full weight of the tank, but they are much simpler than split systems and little maintenance is required.

Split systems have a much slimmer roof profile and are more convenient should tank maintenance be required, but the added complexity of the pump and controller means that failures tend to be more common.

Read the full article, including tables with details on sizes and prices, in ReNew 114.
The tanks are just one component of the solar hot water systems.

Eureka! From coal to solar

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One clever Latrobe Valley enterprise is helping workers switch to low carbon employment, writes Sasha Shtargot.

Drive east out of smog-bound Melbourne along the Princes Highway and before long you are in the haze that perpetually sits in the Latrobe Valley.
Pitted with brown coal mines, the valley has long been in the firing line as the dirty heart of Victoria’s power generation system. It is home to Hazelwood, the most polluting power station in Australia, pumping out over 16 million tonnes of greenhouse gases each year.

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Yet the area that has long depended on jobs from brown coal has started heading in the opposite direction—towards a manufacturing base in clean technology. More precisely, the making of solar hot water units.
Eureka’s Future, a co-operatively run factory, is set to start operating next year with 50 workers in Morwell. With the support of Dandenong manufacturer Everlast and Douglas Solar, it will produce stainless steel tanks with Solar Mio flatplate collectors, Grundfos pumps and Bosch boosters. By the end of 2011, it is expected to be making 500 solar hot water units a month. With rebates and including installation, a Eureka’s Future gas-boosted tank will cost country homeowners $2655 and city dwellers $2755. And it will come with a 10-year guarantee.

Read the full article in ReNew 113
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DIY floor heating, and it’s solar!

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A heated floor can be just the tonic in winter. Per-Steinar Jacobsen shows how he installed his own solar hydronic floor heating.

I have long been an advocate of renewable sources of energy such as solar and wind power. In the mid seventies I built a house in Hahndorf, South Australia, where I installed underfloor heating, radiators and a central heating boiler. I made provision to connect solar panels to the boiler when I had the money to do so.

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Renewable energy is just as important with the house that my wife and I are currently building in Port Germein. However, the renewable energy features have been installed from the very beginning, including the solar hydronic underfloor heating. Here’s how I did it myself.

To start off, I searched the internet for evacuated tube solar collectors. I found some in America which were reasonably priced; interestingly they were used for space heating as well as for hot water. I investigated transportation costs to reflect the true cost of buying from overseas.

In the end I decided to buy them locally from Sunplus CPC Solar in Victoria. I purchased a retrofit (conversion) kit containing four 12-tube collectors. With this kit came three pumps, two temperature pump controllers and some plumbing hardware. This was the easy part, now I had to decide on storage tanks.

Again I searched the internet for suitable hot water tanks. A local hardware store had some 315 litre tanks in stock. I took the model number, rang the factory in Sydney and asked whether it had internal heat exchanger coils. The answer was ‘yes, all our tanks have internal coils,’ so I bought this $1,000 tank, only to find out later that there were no internal coils in this tank. So much for correct information from the manufacturers!

Read the full article in ReNew 104