Heat from groundwater heats the Champagne district of Biel

Four-fifths of the energy for heating and hot water in the Champagne district of Biel comes from renewable sources. What makes this possible are two high-performance heat pumps from CTA, which feed the district heating network with heat from the groundwater.

Champagne is located in the centre of the urban settlement area, on the plain created by the Schüss river, and is therefore largely flat.

Heat from groundwater

Safe, clean energy for heating and hot water: In the Champagne district of Biel, the Champagne heating network has supplied heat from renewable energy since May 2018. Two customised heat pumps from the Swiss cooling and heating specialist CTA are at the heart of the system. They use groundwater as a natural, environmentally friendly heat source.

The first consumers—the high-rise building of the city of Biel pension fund, the Champagne school building, and cooperative residential buildings—have been supplied with heat since October 2017.


The customised CTA heat pumps

  • Two CTAexklusiv large heat pumps with a 1,300 kW total output

  • HFO refrigerant

  • Coefficient of performance (COP) of 3.45

  • Groundwater volume of 6,000 l/min

  • Operating temperatures

    • Groundwater 11/7°C

    • Hot water 50/63°C (max. hot water supply: +75°C)

Four speed-regulated reciprocating compressors

The fact that an entire district can be supplied with heat from groundwater demonstrates the dimensions of the heat pumps. Both units weight around five tonnes each and, with their four speed-regulated reciprocating compressors, supply 650 kW of heating output per unit. The heat comes from the groundwater, which is extracted at a temperature of between 10 and 12°C and cooled by the heat pumps to 4°C.


With their four speed-regulated reciprocating compressors, the heat pumps supply 650 kW of heating output per unit

Sustainable, state-of-the-art solution

The entire system complies with modern, technical standards. The hydrofluroolefin (HFO) refrigerant is used. At the same time, the heating plant meets all the corresponding safety requirements. And, most importantly: the groundwater is transferred to the heat pump via an intermediate circuit. In doing so, the heating network ensures that the sensitive groundwater will never come into direct contact with the refrigerant.

A flagship project

In many respects, the Champagne heating network is a flagship project. The heat pumps are highly (energy-)efficient. Additionally, thanks to the natural heat source, 620 tonnes of CO2 can be saved per year compared to a fossil-fuel heating system. And, consumers have the certainty of knowing that the heat comes from a renewable energy source directly within their region.


Facts and figures from the Champagne heating network

  • Construction, funding, operation: Energie Service Biel (ESB) in collaboration with AEK Energie AG

  • Energy generation system output: 2,400 kW

  • renewable percentage: approx. 80%

  • Groundwater volume: 6,000 l/min

  • Output from CTA-heat pumps: 2x 650 kW

  • Output from natural gas boiler: 1,100 kW

  • Long-distance pipeline: 1.6 km

  • Investment costs: 7 million Swiss francs

  • Supply perimeter: 10.5 hectares


Locations / ContactAbout UsMedia & DownloadsCareer


CTA Ltd.

Hunzigenstrasse 2

CH-3110 Münsingen

Tel. +41 31 720 10 00info@cta.ch

Copyright © 2022 CTA Ltd.

General Terms and Conditions of BusinessGeneral Terms of PurchaseData ProtectionCookie Consent