On the influence of local and zonal hydraulic balancing of heating system on energy savings in existing buildings - Long term experimental research

The application of regulation valves in new and existing buildings allows for proper hydraulic balance of the heating system and in this way it may increase the energy efficiency of heating installation. Unfortunately, to the best of authors' knowledge, there are no long-term field studies that present the level of energy savings achieved by means of commonly used valves in engineering practice, such as thermostatic radiator valves (TRVs), under risers differential pressure control valves (DPCVs), pressure independent balancing radiator valves (PIBRVs), as well as a combination of them. This article presents the results of field research conducted during 6 heating seasons in 16 multi-family buildings assigned to four groups, depending on the type of heating system modernization. The buildings in the first group had existing on-off valves located near the radiator that were replaced with TRVs, and hydraulic balancing of the heating system was performed by means of a pre-set. The second group of buildings was characterized by the installation of DPCVs under the risers of heating installation which was already equipped with TRVs; the third group encompasses the buildings with simultaneous installation of TRVs and DPCVs. The final group consisted of buildings in which the existing TRVs were replaced by pressure independent balancing radiator valves. The energy savings were calculated based on average heat consumption before and after modernization and ranged between 14.6% and 23.8%, depending on the type of the installed valves or their combination. The calculated payback time for the analyzed modernization actions was in the range between 1.4 and 4.9 heating seasons. (C) 2018 Elsevier B.V. All rights reserved.