NA 041
DIN Standards Committee Heating and Ventilation Technology and their Safety
Technical rule
[CURRENT]
VDI 4640 Blatt 2
VDI 4640 Blatt 2
Thermal use of the underground - Ground source heat pump systems
Title (German)
Thermische Nutzung des Untergrunds - Erdgekoppelte Wärmepumpenanlagen