Ringsted district heating – Denmark
Background
Ringsted Forsyning is a company that provides district heating service to 7,000 single-family homes, schools, offices and shopping centers, through a 124 km network. In 2020, the company planned the renovation of the heat generation plant in an innovative way.
Purposes
The new plant supplies the district heating network in a reliable, low-cost and low-carbon way. This comprehensive heat plant redesign focuses on electric heat pumps solutions, utilizing innovative technologies. These heat pumps aim to provide the “heat balance”, recovering heat from all potential sources to boost the district heating system.
Project
Geoclima was involved in the project by Danfoss, thanks to the great experience we have gained in the use of Turbocor compressors. We designed the first chiller with oil-free centrifugal compressors in 2004 and since then we have specialized in obtaining maximum performance from these solutions. So much so that today we are able to make the most of the technology even in systems that produce hot water.
The idea is to transform the heat that is commonly wasted in the air into hot water to be introduced into the district heating network. To achieve this, the condensing temperature must be brought to considerable levels, making full use of the capabilities of the new Turbocor High Lift.
Our solution
We have designed 3 heat pumps, with dedicated heat exchangers to make the most of the efficiency guaranteed by the compressor. The units are designed to use HFO-1234ze, the greenest refrigerant on the market (GWP <1). It is a completely bespoke project, also from the layout point of view: the mechanical room, in fact, is very narrow (2.7x1.2 m), so we had to design the units with a modular approach to ensure extremely easy installation, maintenance and spare part replacement.
Furthermore, thanks to the flexibility of our control software, we were able to completely integrate the heat pumps to the plant’s Build Management System. Finally, the remote monitoring system allows us to know the status of the system in real time.
Results
For Geoclima, designing such cutting-edge heat pumps is an important milestone. We are talking about machines capable of handling extremely variable temperatures, moving from 50 °C to 67 °C on condenser and at the same time from 35 °C to 21 °C on evaporator. Especially the latter are very high temperatures, if you consider that compressors usually work with 6/7 °C leaving water temperature. Added to this is the fact that the units also have to ensure temperature control at variable water flows, which could drop from 100% at full load, to just 10%.
Extreme conditions for our R&D department was able to successfully handle, delivering a high-tech system that represents the reference point in heating solutions with low GWP.
Thanks to this innovative plant, Ringsted is able to achieve very high energy savings and by 2021 they expect to reduce CO2 levels by 88%.
