Efficiency of Passive Utilization of Ground “Cold” in Adaptive Geothermal Heat Pump Heating and Cooling Systems (AGHCS)G.P. Vasilyev, V.F. Gornov, M.V. Kolesova, A.N. Dmitriev and V.G. SilaevaMATEC Web Conf., 77 (2016) 06008DOI: https://doi.org/10.1051/matecconf/20167706008