Problems with using the exhaust air heat pump for renovation of ventilation systems in old apartment buildingsMikola, Alo; Tennokese, Kaspar; Kõiv, Teet-AndrusDanish journal of engineering and applied sciences2015 / p. 44-55 : ill https://doi.org/10.6084/M9.FIGSHARE.1510922 The application of the ground source and air-to-water heat pumps in cold climate areasTennokese, Kaspar; Kõiv, Teet-Andrus; Mikola, Alo; Vares, VilluSmart grid and renewable energy2013 / p. 473-481 : ill The efficiency analysis of the exhaust air heat pump systemMikola, Alo; Kõiv, Teet-AndrusEngineering2014 / p. 1037-1045 : ill