Atmospheric Air –the Effective Source of Low-Grade Thermal Energy for Heat Pump Snow Melting Systems under Climatic Conditions of MoscowG.P. Vasilyev, V.A. Leskov, N.V. Mitrofanova, V.F. Gornov, M.V. Kolesova, I.A. Yurchenko and M.D. FilippovMATEC Web of Conferences, 30 (2015) 05001DOI: https://doi.org/10.1051/matecconf/20153005001