The new Niiralan Kulma Oy office and rental property has been taken into use at Hatsalankatu 37. The goal of Niiralan Kulma Oy, owned by the City of Kuopio, is to build and lease highly energy-efficient A-energy class residential buildings with the lowest possible energy consumption and environmental impact during operation and the lowest possible operating costs.

Based on these environmental and cost targets, a hybrid system was selected for the property, which includes a district heating system and a partial-efficiency geothermal system, the operation of which is enhanced by wastewater heat recovery and centralized supply air cooling. Designed for the property, the hybrid system includes an efficient ground source heat pump, Ecowec hybrid exchanger, hot water and heating accumulators, a ventilation cooling exchanger and a remote monitoring system.

The heating and cooling of the property works mainly with a heat pump system, which is only enhanced by district heating when needed during the coldest time of the year. The efficiency of the heat pump is better than the traditional geothermal system due to the additional heat from wastewater and ventilation cooling. The heat of the wastewater leaving the property replaces about 2-3 geothermal wells, and during the summer, the use of ground cool in cooling the supply air of the air charges the geothermal wells. Both additional heat sources raise the temperature of the heat transfer fluid returning to the heat pump, which improves the efficiency of the heat pump and reduces operating costs.