One-pipe heating costs cut in half

The tenants in two Moscow apartment buildings from the 1960s no longer have to open their windows if their apartment gets too warm during winter. They simply adjust the Danfoss thermostats installed in each room to get the temperature they want.

The thermostats are just some of the components installed as part of a comprehensive modernization project Danfoss has taken part in along with the local company in charge of administration and service of the buildings.

The project shows that it is relatively easy to make old one-pipe heating systems up to 45% more energy-efficient – with a pay-back time of only 3.6 years.

“With this project, we have achieved several important results. First of all, the heat consumption was reduced and the number of complaints from tenants decreased significantly. Second, we now have a new and very reliable system with a high quality of service management,” says Sergey Dzyuba, deputy chief engineer at the local company in charge of service and administration in the buildings.


Bringing one-pipe system back from the grave

But let’s first take a look at the system as it was before Danfoss came into the picture.

One-pipe systems are generally not energy-efficient because hot and cold water share the same return pipe. The apartments were therefore insulated and had new windows installed as part of the Moscow renovation project.

But as the buildings’ old heating system did not leave tenants with the option of controlling the temperature, the apartments often got overheated – even with subzero temperatures outside. The conventional solution would be to install a two-pipe system. And that’s a costly affair.

So the company in charge of administration and service of the buildings opted for a Danfoss proposal to renovate the one-pipe systems instead. The solution included installation of thermostatic radiator valves, automatic balancing valves, and new heating substations with weather compensation in the basements to ensure that heating is automatically adjusted according to the outdoor temperature.

To secure maximum energy-efficiency, Danfoss also equipped the balancing valves with thermostatic sensors. So, when return water temperature exceeds preinstalled settings, the balancing valves automatically reduce flow in the risers.