energy system for Vilpe Oy

The customer’s energy system reform was based on a thorough analysis of the current situation

Tammi Kiinteistötekniikka, a member of the QMG Group, provides HVAC, electrical, automation, and cooling system contracting and building engineering in Ostrobothnia, Finland. Vilpe Oy, also based in Ostrobothnia, is a family-owned company that manufactures plastic products, such as roof hatches and drainage pipes, for the construction industry. Tammi Kiinteistötekniikka was involved when Vilpe renewed its energy system.

The Vilpe factory was commissioned in 1984 and the premises have been expanded several times. Tammi Kiinteistötekniikka has been responsible for maintaining the cooling equipment in the building. When the time came to move away from oil as a heat source, the company offered its energy expertise to the customer.

– Vilpe’s production is energy-intensive and we knew that the waste heat from the plastic manufacturing machines was so great that it could be used to heat other spaces. We proposed an assessment to Vilpe’s management to calculate all energy flows before making decisions on new systems, says Juhani Tammi.

Tammi Kiinteistötekniikka was given permission by the client to carry out an in-depth study of what was happening in the buildings. Oil consumption data was analysed and calculated for different years, taking weather variations into account. The aim was to get as accurate a picture as possible of the heating performance.

– We looked at electricity consumption because it is directly proportional to how much heat can be recovered from the process without using heat wells. We calculated how much the need for cooling reduces the heat demand. When we found that there was excess heat, we considered how to use it more efficiently.  This gave us the idea to recover heat in wells, says Mikko Pieskä, an energy expert who was responsible for producing the energy consumption profile.

Tammi also made use of simulation. In addition to the simulations, a test hole was made for Vilpe to see the thermal response of the rock at that point. The University of Vaasa carried out the measurement of the test pit.

We made a proposal to the client’s management for an assessment that would calculate all energy flows before making decisions on new systems.

Juhani Tammi, Managing Director, Kiinteistötekniikka Tammi

Three well fields and closely laid out wells

The project team at Tammi simulated the situations according to the energy flows to find the best outcome. What makes Vilpe’s system special is that there are 18 wells on the site, each 300 metres deep. They are divided into three different well fields, two of which are conventional and one of which is designed to enhance the heat storage capacity.

In the two conventional fields, the spacing between the wells has been maximised to allow energy to be collected over as large an area as possible and the wells to be used for conventional free cooling and heating. In a field drilled for storage purposes, the heat storage is enhanced, i.e. the wells are deliberately drilled very close together. This is where the higher temperature heat from the cooling machine can be recovered. When the wells are closer together than usual, they cause the surrounding rock to heat up to a higher temperature and also have a lower heat loss, so that the waste heat is better stored for the heating season.

The project also involved planning during the implementation, using existing technology in a new way, which required more than usual from both management and contractors. The system was completed in summer 2021 and has been in trial operation for the winter 2021-2022.