Author: IMP PAN

In two seminars (27 February and 26 April) at IMP PAN in Gdańsk (Poland), Dr M. Dzierzgowski from the Technical University Warsaw presented results of his long-time investigations into the efficiency of oversized district heating (DH) systems in buildings after thermos-modernization. The work was motivated by observations that performed renovations of most buildings have not resulted in expected savings of final energy consumption.

The first meeting directed to house owners and administrations pointed to the necessary heat centers adjustments, which should be performed after renovation. The overestimation of heat exchangers and radiators as well as not corrected heat-supply characteristics of the building lead to grid hydraulic overestimation and very small flux velocities (and deposition of pollutants in the system). Finally, oversupply of heat flux to flats, problems for temperature regulation and too high return temperature follow. However, the observed system overestimation may enable easier transformation of DH to low temperature district heating (LTDH) with even 20% heat-supply reduction.

The second meeting was directed to heat-distribution companies showing them what should be done on the supply-grid side, i.e. temperature decrease below 100 °C and primary energy saving of even more than 10%. To achieve this it requires a change in policy and strategy of heat supply companies, which soon can face strong competition from heat pump solutions. Lively discussions followed the presentation pointing to pros and cons of proposed solutions. A joined meeting of heat-distribution companies with their customer is planned for June

Photocredits: M. Ostachowicz, IMP PAN