Innovative heating network ready for even higher energy efficiency


28 homes extract heat from a single installation, and there are more to follow.

Twenty-eight housing units are provided with heating and hot water from a central plant, without loss of comfort, and with the most efficient use of energy. This was Cordium's objective in the design of a new residential complex in Kuringen Broekerwinning.One phase is finished with residents moving in about a year ago. The next two construction phases of the housing project have started and the technicians are making a concerted effort to achieve even greater energy efficiency.

Cordium interviewed Koen Allaerts, an engineer and researcher at VITO, the Flemish Institute for Technological Research. Together with Cordium, VITO is a partner of the European project 'RESILIENT'. This interview presents the new technology developed and implemented around central energy in combination with a heating network that provides heating for several housing units.

What is a heating network?

The vast majority of housing units (also in larger residential projects) have their own individual energy systems for heating and hot water. This is a simple and effective way of supply, but also makes energy conservation and the use of renewable energy difficult to use on a larger scale. With a central heating system, environmental solutions are possible for a larger number of families. The energy is generated by a central facility and is then distributed to different housing units through a heating network.

Each housing unit has its own station, which can extract heat from the net to produce hot water and room temperature. Both can be controlled, measured and judged so residents remain in power of their own energy consumption.

First project: gas boilers and cogeneration

Phase three of the project "Broeker Winning" in Hasselt, which was built first, has a central plant with district heating that provides heat for 28 residential units. The installation includes three gas-fired boilers and a combined heat and power production unit (CHP). Through the CHP, the plant produces electricity as well as heat. Cordium uses electricity for appliances, lifts and lighting in the garage, entrance, hallways and common meeting area. Each housing unit has a substation that extracts heat from the net for heating and hot water. The project commenced in the winter of 2014-2015. The CO2 saving is estimated to be 7% in comparison with a conventional plant. These savings are mainly the result of the extra electricity that is locally generated by the cogeneration unit.

Next phase: a gas absorption heat pump increases the share of renewable energy

Based on the lessons learned from the as-built first phase, Cordium is now able to take technology a step further for the upcoming construction phases 1 and 2.

Koen Allaerts says: In this new phase, we will use gas absorption heat pumps. These extract heat from the soil that is further heated and then used as an energy source in the homes. This should improve energy efficiency even further and reduce CO2 emissions by almost 30%. Using heat from the soil inflicts the rise of renewable energy.

What about the results?

How much energy is saved? How large is the share of renewable energy in the finished project? For answers to these questions, it is a bit too early, says Koen. To come up with reliable data, a full year of measurements through the four seasons, is needed. We are also, still in a learning process regarding optimal heat generation and adjustment of the system to allow  maximum comfort.

Residents Comfort

What we have been able to determine is that many residents need some-time to get used to these new systems. Elderly people are predominantly living in the "Broeker Winning" and turn up their heating the moment it feels chilly. In a conventional heating system they would immediately feel the difference: the boiler instantly produces a high temperature and in turn the radiators radiate much heat. With these new systems, this is no longer the case. The warming occurs slower and is much less felt in the radiators. This may well give people the feeling that the system is not functioning optimally.  We will have to continue making efforts to help residents understand how these systems work, and how they can make the best use of it.

Social housing can take a leading role, and so it does

Social housing can play an important leadership role in the transition to low energy housing, says Koen. Social housing is a major sector in the Flemish housing landscape. Social housing organisations often renovate and build larger projects where a central heating system may be a smart solution. And – unlike private owners of existing houses -  they don't have to convince their individual residents to participate.  Koen noted that a growing number of social housing companies is eager to accept the challenge. That is an encouraging development.

Knowing more?

Cordium is a partner of the European innovation project 'RESILIENT'. This Limburg housing company is working on the Flemish side in this project together with VITO and Infrax. The European Partnership collaborates with organisations in France, Italy, Spain and the United Kingdom. All pilot projects in this partnership are applications of heating networks with a central heating system.

All information about the European project: