Light your own fire

Heat and power grid

An innovative project is promising total independence of the local energy grid. Veronica Stivala plugs into the brains behind the revolutionary idea of a heat and power machine. 

An electrical generator that will free us from reliance on the grid is slowly nearing completion. Such devices are already used around Europe for central heating in homes, and promoted for use in residential and light-commercial buildings in Japan. Yet the University of Malta (UM) team have honed in on one unique factor: households will be able to disconnect their own combined heat and power (CHP) devices from the grid. 

Prof. Joseph Cilia and his team of researchers at the Department of Industrial Electrical Power Conversion are developing a CHP machine that will provide electrical and thermal energy for households. According to the European Commission’s Energy Union Factsheet, Malta has a low demand for heating compared to other EU countries, but many households state that they are unable to keep their houses warm in winter.

Currently the CHP devices available require an external electrical grid to run. On the other hand, users of this UM team’s CHP device can hook theirs to an independent inverter, which transforms the direct current generated in the device to alternating current (AC) used by appliances. This way households can consume the electricity generated by the machine. The heat produced can also be directed to a boiler, water tank, underfloor heating, or elsewhere, giving the household added flexibility and freedom when it comes to its energy consumption.

People would be able to control their device and energy distribution around their home.

These devices close the self-reliance gap between fossil fuel powered devices and green energy generators. Most solar panels require an existing AC supply to operate, plugged to the local grid. No matter the energy generated, the household is still dependent. Solar panels work best when integrated into a larger system with other energy-generating devices to act as a consistent backup. What the UM team is proposing is to use the generator in combination with solar energy and a battery to store that energy. This gives the user autonomy from the grid, as well as the option to use cheaper, greener alternatives.

Being able to produce, store, and use your own energy is the goal behind this research project. The CHP machine currently relies on an external source of energy to get it going in the first place — an LPG (Liquefied Petroleum Gas) cylinder for instance. LPG gas is the best option the team has found, being cleaner than other fuels and easily available. While that might sound like a catch, Eryl Vella, one of the team’s engineers, explains that any fuel is used as efficiently as possible, and they have plans to run their engine on ethanol. Ethanol can be made from plants. They are aiming for 90% efficiency by recovering and using energy escaping from both the engine and exhaust, which is much more efficient than car engines.

‘We are hugely in favour of renewable energy,’ stresses Vella, adding that their aim is to use combustible fuels efficiently to fill in the gap where green energy currently lacks. The team is also working on turning it into a standby generator which, in a country notorious for its numerous power cuts, will surely be a relief. They have included a small battery backup so that if the power goes out, the CHP device can provide around 3.5KW of electrical power (enough for three ACs), and some 6KW of heat. 

As the project matures in its testing phase, and the reality of being able to have a CHP appliance in your home inches towards reality, Vella explains what exactly this would entail. One of the primary advantages of this device is its size – roughly around that of a washing machine, meaning it can easily be tucked away in a cupboard. When asked about the dangers this could incur, Vella says it is comparable to the danger of having a gas heater or gas hob indoors. Yes, having a compressed flammable substance indoors comes with its own risks, yet they ‘will introduce as many safety measures as possible, such as gas and temperature sensors. These will ensure the device won’t overheat. It will sound an alarm to alert the user should it detect any hazardous gas leaks. These sensors could then be used to immobilise the device should any potential danger be detected.’

The CHP water loop can be connected to the ports of the user’s choice, be they the water tank or underfloor heating. The team is aiming for a wireless interface, which means you would not need to press anything. It would be accessible through an app and the goal is ‘to have it completely run from your smartphone or tablet.’ People would be able to control their device and energy distribution around their home.

They are aiming for 90% efficiency by recovering and using energy escaping from both the engine and exhaust, which is much more efficient than car engines.

When it comes to maintenance, this should be a breeze: the device runs on brushless technology, so there is no friction. It will require little to no maintenance. Indeed, the device uses LPG, is housed in a closed-off environment, and running on constant revolutions per minute like a motorcycle — meaning that the frequency of turning is predictable. It will only need an oil change every once in a while.

The next stage of the project is an experiment in immersion. The four prototypes plus the original CHP device will be installed in five houses and run for a period of at least one year. The team will then gather data for the engineers to accurately calculate energy savings and tweak their product to perfection. 

When can we expect to see the CHP machines on the market? A conservative estimate is 2022, says Vella, whose team have their eye on the local and international market. At an estimated cost of €4,500 per unit, generating all our own energy and thus having more freedom and control in its production is fast looking set to become a reality.   

The project, titled A Smart Micro Combined Heat and Power System, is financed by the Malta Council for Science and Technology, for and on behalf of the Foundation for Science and Technology, through the FUSION: R&I Technology Development Programme.

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