Mechanical ventilation system with heat recovery in renovated apartment buildings : a case study

Abstract

If there is no additional mechanical ventilation system installed in the existing buildings originally designed with natural ventilation, then after renovation they become highly airtight. Air tightness reduces heat losses due to infiltration, but it also significantly decreases indoor air quality, as there is limited supply of fresh air. Energy losses due to ventilation and air infiltration represent a huge amount of the energy delivered for space heating. Solution of the problem would be a mechanical ventilation system with a heat recovery unit. The advantage of using heat recovery units is energy saving, and as a result, savings on costs for the operation of the ventilation system. This paper describes renovation carried out in a 4-storey apartment buildings. During the study, three buildings have been analysed; all of them are built in 1970, using the same materials, the same constructive solutions. Renovation was carried out by one company, using the same materials and same renovation principles. The only difference after the renovation is that in two of the buildings new centralized mechanical ventilation system with a heat recovery unit was installed, while in the third building a natural ventilation system was left. The arrangement of the mechanical ventilation system is rather innovative as the ventilation ducts in the building for fresh air supply are integrated into the facade’s insulation layer, they enter the living room through the wall directly behind heating radiators. The main question studied during the research is the efficiency of mechanical ventilation system’s heat recovery.

Pastatai, kurie yra suprojektuoti su natūralia ventiliacija, įdiegus mechaninę ventiliacijos sistemą, po renovacijos tampa labai sandarūs. Sandarumas sumažina šilumos nuostolius dėl infiltracijos, tačiau dėl to žymiai sumažėja patalpų oro kokybė, nes yra ribojamas gryno oro patekimas. Naudojamų šilumos atgavimo įrenginių privalumas yra energijos taupymas. Šiame straipsnyje aprašoma renovacija vykdoma 4 aukštų daugiabučiuose pastatuose. Tiriamieji pastatai yra 1970 metų, pastatyti taikant tas pačias medžiagas ir tuos pačius konstruktyvius sprendimus. Renovacija atlikta naudojant tas pačias medžiagas ir vienodus atnaujinimo principus. Skirtumas tas, kad po renovacijos dviejuose pastatuose įdiegtos naujos centralizuotos mechaninio vėdinimo sistemos su šilumos atgavimu, o trečiajame pastate liko natūralaus vėdinimo sistema. Eksperimento metu siekiama įvertinti mechaninės vėdinimo sistemos šilumos atgavimo efektyvumą.