DemoDAIRY and Russell White – Using Solar Energy To Heat Water

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Experience of installing dairy solar hot water systems

Louise Sheba from DemoDAIRY in south west Victoria says that they were looking for win-win options in energy and cost savings and greenhouse gas reductions.

In 2007, they retrofitted two solar hot water systems for the purpose of heating the water for the dairy. The anticipated benefits of this measure were to improve the profitability and contribute to the long term sustainability of the business.

In 2008, the South West Sustainability Partnership provided funding for an energy audit of DemoDAIRY. The purpose of this audit was to quantify the effect of the solar hot water system and to outline other changes that could be implemented. Louise says she wanted to focus on getting the biggest bang for their buck when looking at energy reduction.

The energy audit, conducted by a professional consultant, highlighted that heated water used in dairy cleaning was a major user of energy, costing both money and greenhouse gases. The report also itemised a range of other things that the dairy could do to reduce its energy consumption. These included investing in a bore water pump, precooling water in an insulated underground tank and insulating the hot water pipes.

The cost of the solar system was subsidised by both the rebates from Renewable Energy Certificates and a grant from the Corangamite Shire, and came to $5140 for the double system. This does not include installation costs.

Louise believes that the introduction of solar hot water has reduced the dairy’s energy costs.

Table 1: Preliminary energy analysis from Demo Dairy.

It is obvious that even though cow numbers have been increasing, the use of mains energy been reducing since the solar hot water system has been retrofitted.

When asked if she would recommend solar hot water systems to other dairy farmers, Louise said “absolutely” and went on to say “the earlier you embrace new technology, the more adaptive you will remain in the future. DemoDAIRY aims to show leadership, as well as being future directed, and technologically savvy.”

Louise believes that it is important to remember to focus on what is within your control, keep an eye on global drivers, but focus on things you can change.

Key things to remember:

• The water from solar can come out very hot and potentially cause problems with parts of the rest of the system if not set up properly.
• There can be issues if the solar hot water system does not compliment the dairy’s needs, such as providing the amount of water required.
• Water quality going into the system is very important

Russell and Linda White: Farmers will not do anything that is not a win-win!

Russell White’s family has been farming in the Coorimungle area since the land was originally settled. However, this does not mean that Russell is not innovative on his farm.

In fact, he is one of a handful of dairy farmers in Victoria with solar panels to heat his water for the dairy. Russell’s farm is 320 acres in south west Victoria, where he milks around 200 cows.

His motivation for the installation of solar panels in 2005 was two fold: to reduce the cost of his electricity bill and to reduce his environmental impact. As Russell says: “If there is not a dollar in it for the farmer, you won’t get their attention.”

Even though Russell and Linda are undecided about human induced climate change, they believe that there is no harm in doing the right thing by the environment and your hip pocket.

Russell and Linda were able to explore solar panels as an addition to their new dairy because they were efficient and attracted a high rebate. They researched the solar panels through the internet and found a solar company with products that suited their needs. After consultation a suitable system was devised, including rebates, and was estimated to have a five-year pay back period. The system cost the Whites around $6,500, including installation.

Four years after installation, Russell and Linda are still enthusiastic about their decision. Russell understands that the solar hot water system will have at least a 20 year life span, provided it is treated well and tank water is used through the system instead of dam water. This prevents silting.

Russell and Linda had eight banks of evacuated tubes installed on the roof of the dairy, connected by a pump to circulate. The system can get up to over 100 degrees Celsius. Russell aims for hot water, to wash down the plant, to ensure the best results from his chemicals. This means a booster heater is often required in winter to achieve these temperatures.

The challenges that Russell and Linda faced initially were:

• Ensuring the solar panels were positioned with the correct aspect and angle for maximum heating.
• Changing the water source water to rain water to avoid silt in the solar hot water system.
• Ensuring flow rates through the system were high enough to avoid unwanted backflow of very hot water (100 degrees Celsius). This was solved by a brass check valve for one way water flow and avoided further melting of PVC pipes.

The Whites have sparked a lot of interest from the dairy community, with many local farmers asking to ‘take a look’. Russell says that he would definitely install the system again, as heating water and cooling milk are the biggest dairy power costs. He warns however, that farmers looking to put a system in must do their homework and shop around, “they need to ensure payback is within a reasonable period.”

Solar summary

Even with Renewable Energy Certificates, it is important to estimate the pay back period for the solar hot water system chosen. If you are looking to get a solar hot water system, then be sure to shop around to get the best deal for your farm. Do not only consider price, but other issues, such as having access to local service assistance and adequate structural support on-site. You will probably need to invest in a gas or electric booster system, as solar hot water systems may not be able achieve the desired temperature all year round. As a rule of thumb water is heated to just over double the maximum air temperature on any given day, although this will vary with different systems.

The key message with solar hot water is if you are going to install, do your homework first and research what government Renewable Energy Certificates you are entitled to. Solar hot water in the dairy system can reduce both the electricity cost and greenhouse gas production.

For more information

Office of Renewable Energy Regulator - www.orer.gov.au/swh/index.html

Cowtime (Reducing and monitoring dairy energy usage) - www.cowtime.com.au

DemoDairy - www.demodairy.org.au

DPI is seeking positive and practical stories about climate change action. Contact us on 136 186 if you have a story to share.

View all the Farmers Taking Action case studies online at www.dpi.vic.gov.au/climaterisk

Through the Future Farming Strategy, the Victorian Government is providing information to enable farm busines ses to plan for climate change.