FLEXYNETS

©Alperia SpA (pictures of District Heating plants in northern Italy).

Energy efficiency is a prominent global issue, with researchers looking to both develop new technologies and manage existing resources more effectively. Dr Roberto Fedrizzi tells us about the FLEXYNETS project’s work in developing a new generation of District Heating and Cooling networks that will reduce energy losses during transportation, while also facilitating waste heat recovery

Heating and Cooling networks play a crucial role in modern society, helping to transport energy to residential buildings and businesses. However, existing networks are prone to significant heat losses, says Dr Roberto Fedrizzi. “The current third generation networks work at higher temperatures – around 90° C – than the ground level temperature. There are energy losses of around 10-20 percent during transportation,” he explains. Based at the EURAC research centre in Bolzano, Dr Fedrizzi is the Principal Investigator of the FLEXYNETS initiative, a Horizon 2020 project which aims to develop a new, intelligent, more efficient generation of District Heating and Cooling networks. “We aim to dramatically reduce the distribution temperature, and as such to reduce thermal losses through the pipeline to nearly zero,” he outlines.

These fifth generation networks will be designed to work at ‘neutral’ temperatures of between 15-20°C, close to the groundlevel temperature, which is in the range of 10ºC. While this will help reduce energy losses, with obvious benefits for energy companies and other utilities, thermal energy delivered at such low temperatures is not well-suited to household purposes. “You cannot have a shower with that, or wash dishes,” acknowledges Dr Fedrizzi. A reversible heat pump will be used to increase the water temperature to a level where it can be used for domestic purposes; while this shifts the initial costs slightly towards households, it will lead to longterm savings. “Where you can save money is in the energy bill that you pay, as you can reduce the amount of electricity that you use to warm up a building through a very effective operation of the heat pumps. So that’s an economic saving from the new generation of district heating and cooling networks,” explains Dr Fedrizzi.

The network is also designed to deliver effective cooling, alongside this heating capability, while waste heat is recovered for heating purposes. These two aspects of the network can work together simultaneously on the same pipeline, so that the network can operate in a way that reflects local climate conditions and seasonal demands. “There is a central unit balancing hot and cold loads. So in the summer months there will be a centralised chiller that would balance between warm and cold loads, while in winter there would be a centralised boiler,” says Dr Fedrizzi. The reversible heat pumps and chillers have proved effective in exchanging heat with the network, now

Flexynets concept of a DHC network.

the main priority is integrating the key technologies with the network. “We are trying to understand how to integrate the heat pumps at a local level with the network. Then we are investigating how to manage the network itself as a whole,” continues Dr Fedrizzi.

This work very much fits in with the wider goal of improving energy efficiency. While a great deal of research attention has focused on developing new technologies to harvest renewable sources of energy, Dr Fedrizzi believes it’s also important to manage the solutions currently available on the market more effectively. “First of all, we aim to manage thermal energies – both cold and warm – more efficiently. Secondly, we aim to integrate as much of the wasted energy or heat as possible in the network,” he outlines. This historically has proved to

be a difficult task, as previously networks operated at higher temperatures. “There are not really many energy sources that can be integrated at higher temperatures, since there are not really many processes that can provide continuous thermal fluxes at higher temperatures, where you need it,” explains Dr Fedrizzi.

The next generation of District Heating Networks will be designed to integrate heat from a variety of sources, including biomass, photovoltaics and cogeneration. Researchers also aim to integrate waste heat, further helping improve energy efficiency. “Refrigeration units at supermarkets, air conditioners and launderettes all waste heat for example. That waste heat could be conveniently recovered into these new generation networks due to the lower temperature. The network is a long pipeline, and you can recover waste heat along it where it is available,” continues Dr Fedrizzi. Effective management and integration of the network could open up opportunities for companies to recover waste heat and sell it back to the network; Dr Fedrizzi points to the example of a supermarket. “A supermarket using refrigeration units could recover the waste heat normally rejected into ambient - with associated electricity costs - and use it as a business opportunity,” he points out.

Researchers are investigating the potential to develop a ‘feed-in’ scheme similar to existing plans where householders with solar photovoltaic panels on their roofs can sell excess energy back to the grid. In the case of a supermarket, this kind of scheme would require an initial investment in connecting to the network, but again it would pay dividends over the long-term. “You have a payback due to the fact that the utility company would pay you for the energy that you put back into the network. This is a win-win situation,”

says Dr Fedrizzi. “The city re-uses energy that would otherwise have been wasted into the ambient, and the utility company can provide heat to users at a lower cost.”

This research has attracted the interest of the commercial sector, with companies looking for innovative solutions to deliver heating and cooling. Researchers are developing simulation models to identify the optimum operation of these fifth generation networks, and Dr Fedrizzi is keen to establish closer links with utility companies. “We want to work with utility companies who could be interested in demonstrations of these kinds of solutions,” he says. The project’s concepts will be tested in a laboratory currently being constructed at EURAC, which will closely mimic the conditions in practical applications, so that the needs of the commercial marketplace can be taken into account. “We want our research to have an impact in the real world,” stresses Dr Fedrizzi.

Fifth generation, Low temperature, high EXergY district heating and cooling NETworkS (FLEXYNETS)

FLEXYNETS will develop and demonstrate a new generation of intelligent DHC networks that reduce energy transportation losses by working at “neutral” (15-20°C) temperature levels. Reversible heat pumps will be used to exchange heat with the DHC network on the demand side, providing the necessary cooling and heating for the building.

Project Funding 2 million euros

Please see website for details

Dr Roberto Fedrizzi Coordinator of the Sustainable Heating and Cooling Systems research group, EURAC research Institute for Renewable Energy Via G. Di Vittorio 16, I-39100 Bolzano T: + 39 0471 055610 E: roberto.fedrizzi@eurac.edu W: http://www.flexynets.eu/en/

Dr Roberto Fedrizzi

Dr Roberto Fedrizzi is Coordinator of the Sustainable Heating and Cooling Systems team since 2009. EURAC research. His expertise is in development and management of national and international research projects, laboratory testing of sorption and compression heat pumps, design of hybrid heating and cooling systems exploiting solar energy and heat pumps.