System, an arrangement and method for heating and cooling

A heating and cooling system for conditioning several building spaces, the heating and cooling system comprising:

• a secondary thermal network for circulating secondary working fluid, the secondary thermal network comprising a supply line for circulating high-temperature secondary working fluid and a return line for circulating low-temperature secondary working fluid;
• two or more connection lines provided to the secondary thermal network, each connection line extending between the supply line and the return line and arranged to connect the supply line and the return line to each other;
• two or more primary heat exchangers arranged to the two or more connection lines and arranged to provide primary heat exchange connection between the secondary thermal network and the building space;
• and
• a geothermal heat exchanger arranged in connection with the secondary thermal network,
• wherein the geothermal heat exchanger comprises a geothermal network having a rise pipe and a drain pipe, the rise pipe is arranged inside the drain pipe, and the rise pipe of the geothermal heat exchanger is provided with a first thermal insulation surrounding the rise pipe and extending along at least part of the length of the rise pipe from the ground surface.

An arrangement for heating and cooling of several building spaces or buildings, the arrangement comprising:

• two or more building spaces or buildings;
• a secondary thermal network for circulating secondary working fluid, the secondary thermal network comprising a supply line for circulating high-temperature secondary working fluid and a return line for circulating low-temperature secondary working fluid;
• two or more building connections arranged parallel to each other and between the supply line and the return line of the secondary thermal network, the two or more building connections comprising a primary heat exchanger provided in connection with the two or more building spaces or buildings;
• and
• a ground hole provided into the ground and extending from the ground surface, wherein the depth of the ground hole is at least 300 m, and that the arrangement comprises a geothermal heat exchanger provided to the ground hole having the depth of at least 300 m and arranged in connection with the secondary thermal network.

A method for heating and cooling of several building spaces or buildings, the method comprising:

• circulating secondary working fluid in a secondary thermal network;
• performing two or more first heat exchange steps parallel in the secondary thermal network between the secondary working fluid and a primary working fluid of the building space or building in connection with two or more different building spaces or buildings;
• and
• performing a second heat exchange step between the secondary working fluid circulated in the secondary thermal network and ground with a geothermal heat exchanger arranged in a ground hole and arranged in connection with the secondary thermal network,
• wherein the method comprises:
• performing the second heat exchange step between the secondary working fluid circulated in the secondary thermal network and ground with the geothermal heat exchanger in the ground hole, the ground hole having depth of at least 300 m.