Solar Progress - Issue 1 2014

Page 28

Innovation: solar hot water

Hot PV – ™

solar PV hot water and much more Barbara Elliston of Easy Warm has devoted time and energy – so to speak – into delivering an all electric solar hot water system for households. Here she tells us why she felt compelled to develop such a device, and how a good idea became a great reality with long-term benefits for users.

Over a cup of tea at morning smoko a number of years ago, a “resilient communities” friend introduced me to an engineer facing significant odds trying to get a single-bladed wind turbine developed and commercialised. Although my engineering and commercial background is from “bigenergy”, the corporate energy world including aluminium smelters, power stations and thousands of kilometres of transmission lines, we all shared an objective: to ensure that our communities were as self-reliant and resilient as possible, under a number of scenarios facing our communities now and perhaps even more so in the coming years. This gathering had been at Otago University, where CSAFE (Centre for Sustainability – Agriculture, Food, Energy and Environment) had coordinated an energy symposium. The relevance of mentioning CSAFE was that it has been carrying out research into consumer energy behaviour, including into their water heating preferences. The research indicated that the desire to use solar hot water was very high, but there were too many hurdles when customers actually wanted to purchase and install the systems. Not only are building consents required for solar hot water systems in New Zealand, one council in New Zealand even requires roof truss drawings before a consent is issued – for systems without any tanks on the roofs. As an importer of evacuated tube solar hot water collectors into New Zealand, I was more than familiar with the barriers to uptake of solar hot water in New Zealand. The smoko discussion included my contention that with solar PV becoming much more affordable, it is better to employ solar PV for water heating, rather than sticking with the old solar hot water technologies that required pipes and plumbing. Installing solar PV water heating was simple in comparison.

Stats and facts A look into energy use statistics shows that electric storage water heating is clearly identifiable as a homogenous (single) technology that is a significant user of grid supplied electricity in both Australia and New Zealand – what this gobbledegook means is that there is a large market out there for substituting PV electricity for grid electricity for the purpose of heating water!

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And solar PV water heating can be installed on people’s roofs to do just that – and with a power station on your roof, other possibilities for self-reliance and resilience will also emerge over time. For example, someone suggested that underfloor heating may also be able to use this same technology. From a self-sufficient, resilience point of view, installing solar PV water heating also means that a large chunk of your power bills going into the future will disappear, because installing the system is in effect pre-paying for your future power bills – this is a huge concern for people who are retired or starting to think about their retirement. Hot PV™ is born – it is our response to the brilliant opportunities available, now that PV has become affordable to many households, to give them back control of their power bills.

Hot PV™ - a patented cool new product on the solar PV market The system consists of a PV array, a special inverter, and an EMU – energy management unit It is an off-grid PV system that is connected directly to your hot water cylinder. This means that you can consume the power you generate yourself, straight into heating your water rather than fed into the grid and get paid peanuts for it. This own consumption helps to reduce your power bill, and means that your array gets to payback faster, especially when the alternative is to earn 8c/kWh feed in tariff (or less). You can think of it as a brand new kind of solar hot water system: but using solar PV panels instead of those collectors that are filled with water or. And just like the old kind, the grid is used to boost the element – but you get to choose when that happens. One of the things about PV panel prices falling over the past few years is that the price is now at a level where it is economic to use PV generated electricity, an all-purpose premium fuel, even to heat water. Hot PV™ is a completely new way of thinking about generating and using your own power.

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