During the following decade, a smart energy system will be built in Oulu’s Karjasilta area. The smart fourth-generation district energy system will both heat and cool the area’s properties. The residental area will be built by Hartela Oy and Oulun Energia is responsible for implementing the district energy system. Karjasilta’s hybrid heating and cooling system is manufactured and supplied by HögforsGST.

Karjasillan Kulma, which consists of 11 residential apartment buildings, a renovated school building and an underground garage, is a modern residential area which boasts numerous housing and service solutions of the future, smart energy system being one of them. Environmental friendliness, energy efficiency and comfort of living are top priorities, as the goal for Karjasilta is to profile itself as a pioneer in future housing and service solutions.

– Karjasillan Kulma is a regional entity where the possibilities of the district heating network can be fully utilized. The project is a step towards fourth-generation district heating and energy recycling, says Kimmo Alatulkkila, Director of Heating Services at Oulun Energia.

Karjasilta is the largest smart energy system project in HögforsGST’s history

HögforsGST will supply the Karjasilta area with a fourth-generation district energy system that generates both heat and cooling. Juha Virkki, Business Director of HögforsGST, talks more about the system that will be installed in Karjasilta.

– We have implemented quite a few traditional district heating systems, but the system coming to Karjasilta is the largest smart district energy system we have ever designed and manufactured. Heating and cooling are produced by a combination of heat pumps and district heating. In addition, the heat generated from the production of district cooling is utilized in heating, and surplus heat can be transferred to Oulun Energia’s district heating network. One could say that this is a true Megahybrid, Virkki laughs.

Karjasilta’s hybrid heating and cooling system is by HögforsGST.


In addition to its state-of-the-art nature, the system is delivered as a prefabricated entity. The entire system with pipes and cabling is manufactured and tested at HögforsGST’s Leppävirta factory before delivery. The on-site installation of the system is much faster compared to traditional delivery method.

– Thanks to prefabrication, the number of parts to be manufactured on-site is reduced, and thus the amount of work is reduced as well. In this case, the installation will be carried out by a local contractor with the support of an expert from HögforsGST. We tested a similar delivery method in a hybrid system previously delivered in Jyväskylä, although back then our own team took care of the installation, Virkki adds.

Lessons learned in an EU project helped to design Karjasilta’s system

The Karjasilta system is not only showcasing the development of the district heating industry, but also how a pilot solution from a publicly funded project can be developed into a commercially viable solution. Åke Vikstedt, HögforsGST’s Key Account Manager, says that Karjasilta’s energy system is based on a similar system previously implemented in Turku.

– Last year, within the framework of the EU-funded RESPONSE project, we delivered a system to the Turku Student Village, in which 4GDH solutions were piloted in a district heating system. The experiences gained from the Turku pilot project also enabled the development of a similar system in Oulu. The Karjasilta system is like a full 4GDH town, but in a smaller scale, Vikstedt says.
 

Although the Karjasilta and Turku regional hybrid systems are mostly new technology, familiar and proven technology lies at the core of both systems. Fiksu Control System developed by HögforsGST controls the operation of both systems.

– Our Fiksu Control System scales well to the needs of systems of different sizes. In Oulu, for example, we have properties ranging from two terraced houses to an entire residential area. Although the size difference between the sites is huge, Fiksu Control System works great for both sites, says Vikstedt.