News / 10.6.2014

Solar energy for district heat customers

In cities and apartment blocks, sensible construction can be combined with smart city energy. With the aid of windows, solar energy can be used for heating in the winter season.

The dense urban structure provides new opportunities for increased use of renewable energy, recycling of energy flows, and emissions reduction. The research project SunZEB – PlusEnergy in the City, which was launched in the spring, aims to create an optimal energy solution for areas connected to district heating and cooling. In addition to the building’s own energy use, the project takes into account innovative recirculation and reuse of energy in new and renovated buildings. A cooled building does not use cooling energy in a negative sense, but it acts as a source of renewable energy.

– By adding the benefits of new kind of construction to a combined district heating and cooling system and by examining the energy cycle as a whole, we will gain a pioneering solution at the core of clean technology, i.e. cleantech, attracting international demand, believes Development Manager Jouni Kivirinne of Helsingin Energia.

The energy system in Helsinki already utilises renewable energy sources in a very efficient way: biomass, seawater and solar heat. During a warm summer week, up to 1,000 MWh of solar heat can be produced with district cooling. This amount corresponds to one week’s hot water need of 25,000 people.

Cleantech brings added value to customers

In a SunZEB building, the properties and size of windows and the building services technology are designed to achieve the best possible architecture and indoor conditions in terms of light and indoor climate. Windows are dimensioned so that solar energy can be utilised as much as possible for heating the building during the winter season. In the summer period, renewable solar energy is produced into the district heating system with the required cooling.

– We can already see that this is a solution that has full potential of achieving a situation where a property cooled with district cooling in the summer period produces solar energy in excess of its own need. With buildings cooled with district cooling, renewable solar energy is produced in a dense urban structure without separate solar heat collectors. This is a significant factor that will be in evidence in environmental certification and the value of buildings, Jouni Kivirinne points out. The research project is progressing within multidisciplinary expert groups, and results can be expected this autumn.

The members of the SunZEB – PlusEnergy in the City project are:

Confederation of Finnish Construction Product Industries Finnish Real Estate Federation Skaala Oy Uponor Oy Projectus Team Oy Finnish Energy Industries Turku Energia Oy Tampereen Kaukolämpö Oy Hyvinkään Lämpövoima Oy Ministry of the Environment Ministry of Employment and the Economy RAKLI ry FiGBC ry VTT Technical Research Centre of Finland Aalto University Architectural Office Kimmo Lylykangas

Read more about the topic

Solar energy