Fjärrkyla

Fjärrkyla, known in English as district cooling, is a system for supplying cooling energy to multiple buildings from a central plant via an insulated distribution network. Rather than each building installing and operating its own refrigeration equipment, customer buildings connect to a shared central system that provides cooled water or glycol through underground pipelines.

A typical fjärrkyla setup consists of an energy center (central cooling plant), a network of insulated pipes, substations at individual buildings, and building-side heat exchangers or cooling stations. The central plant produces chilled water, which is circulated through the primary loop to delivering points in connected buildings. At the building, heat exchangers transfer the cooling effect to the internal cooling systems, and the warmed water returns to the plant to be cooled again. The system can incorporate thermal storage and may use various cooling sources, including electric chillers, heat recovery, or integration with renewable or waste heat.

Key advantages include improved energy efficiency through scale, reduced refrigerant usage in buildings, lower noise and maintenance requirements inside structures, and easier integration of renewable energy or waste heat. Fjärkyla also enables centralized management and monitoring, potentially lower capital costs for individual buildings, and easier district-wide planning.

Challenges involve high upfront infrastructure costs, network heat losses, precision in balancing supply and demand, and the need for coordinated tariffs and service contracts. The approach is prevalent in many Nordic and European cities, where it serves offices, hospitals, data centers, and university campuses, contributing to lower environmental impact and more flexible cooling capacity.