a hook 30 at the inside of the shelter for an assembly winch for the electronic material at the shelter bottom a door 32 opens toward the outside with air tight seals such door being made of a frame with a heat insulating packing the shelter insulating layer 34 is made of foamed polyurethane polystyrene or similar heat insulating material the thermal capacity is fixed to the shelter inside walls it consists of a set of plastic square tubes 36 slightly shorter than the total height of the wall and filled with a suitable liquid and sealed at the top and bottom in less severe climates and with higher admissible inner temperatures it is possible to avoid the outer screen and in case of minor requirements or improvements in the climatic conditions also the inner solar screen in a tested screenless embodiment the sizes of the inner cell were 1 70 u00d7 1 70 u00d7 2 m with an insulation formed by a 30 cm thick foamed polystyrene layer the thermal capacity was formed by 220 l of water contained in 24 round plastic tubes 1 90 m height inner diameter 80 mm the results of tests carried out with an inner dissipated power of 40 and 30 w are shown in the diagram of fig5 wherein the upper curve indicates the shelter inside temperature point a indicates a reduction of the dissipated power from 40 to 30 w while the lower curve indicates the values of the outside temperatures the values of the thermal capacity shall be proportional to the desired damping of the outside temperature variations and to the thermal resistance of the walls it is to be understood that the illustrated embodiments may undergo modifications in particular according to the operational requirements without.