Retrofit Measures in Old Elementary School Buildings Towards Energy Efficiency

A study on thermal retrofit of Portuguese elementary school buildings is presented. The type of school under analysis is one adopted by a large construction campaign that began in the 1940's. This building stock has a very poor thermal performance and their retrofit was evaluated starting with a case study of a school in the central region of Portugal, where some experimental measures were performed and a calculation method was applied for the heating energy consumption estimation. A solution for the thermal retrofit of the school building external envelope was optimized and the effect on heating energy consumption was evaluated, using ECOTECT, resulting in a reduction of 52% of heating energy needs. The national impact of the thermal retrofit of the whole building stock was characterised in terms of energy savings. Finally, the pre‐heating of the ventilation air was also tested as a complementary measure and its effect evaluated. The solution tested may provide up to 1000 kWh/year of extra heat gains by pre‐heating the ventilation air. It must be underlined though that the performance of these systems is dependent on the thermal properties of their components so higher reductions can be achieved with the improvement of these properties. Santrauka Straipsnyje pateikiami Portugalijos pradines mokyklos šiluminio atnaujinimo tyrimai. Analizuojamos mokyklos tipas yra vienas iš taikytu po 1940 metu prasidejusioje plačioje statybos kampanijoje. Šios pastatu grupes šilumines charakteristikos yra labai prastos. Ju atnaujinimo vertinimas buvo pradetas nuo centrineje Portugalijoje esančios mokyklos, kurioje buvo igyvendintos kai kurios eksperimentines priemones, ir energijos sanaudoms nustatyti pritaikytas skaičiavimo metodas. Pastato išoriniu atitvaru šiluminio atnaujinimo sprendimas buvo optimizuotas ir jo itaka šilumines energijos sanaudoms nustatyta naudojant ECOTECT. Šilumines energijos poreikis sumažejo 52 %. Iš viso pastatu fondo šiluminio atnaujinimo itaka nacionaliniu mastu vertinta sutaupytos energijos kiekiu. Pabaigoje kaip papildoma priemone buvo išbandytas pirminis vedinamo oro pašildymas, nustatytas jo naudingumas. Išbandytasis pirminis vedinamo oro pašildymas gali suteikti iki 1000 kWh/metus papildomo išsiskiriančio šilumos kiekio. Pabrežtina, kad nors šiu sistemu veikimo charakteristikos priklauso nuo ju komponentu šiluminiu savybiu, gerinant šias savybes galima daugiau sumažinti energijos sanaudu.