Use of a heat pump in an industrial drying installation for drying a material chosen among wood and sludge, said heat pump comprising: - first and second heat exchangers adapted to exchange heat respectively with the source fluid (Fs) located in the vicinity of the first heat exchanger and the external fluid (Fe) located in the vicinity of the second heat exchanger, each of said first and second heat exchangers having an inlet and an outlet, - a coolant selected from among a hydrofluorocarbon coolant and a hydrofluoroolefin coolant, - a coolant circuit suitable for circulating the coolant between the first and second heat exchangers, said coolant circuit comprising a compression unit having an inlet connected to the outlet of the first heat exchanger and an outlet connected to the inlet of the second heat exchanger, and an expansion unit having an inlet connected to the outlet of the second heat exchanger and an outlet connected to the inlet of the first heat exchanger, said installation comprising: - a chamber having an inlet and an outlet, - a treatment system located in the chamber, the treatment system is a drying rack intended to receive a material to be dried, - a circuit of external fluid, suitable for circulating air as the external fluid (Fe) successively in the vicinity of the second heat exchanger and in the vicinity of the treatment system, said external fluid circuit being further adapted to circulate air as the external fluid downstream of the treatment system, as the source fluid, in the vicinity of the first heat exchanger, the use comprising: - arranging the material on the drying rack, - circulating air as the source fluid and the external fluid (Fe) between the inlet and the outlet of the chamber, air circulating successively in the vicinity of the second heat exchanger, in the vicinity of the drying rack and in the vicinity of the first heat exchanger, - circulating the coolant, the use being characterized in that the inlet and the outlet of the chamber are respectively arranged upstream and downstream of the treatment system and the first and second heat exchangers are respectively arranged in the vicinity of the outlet and of the inlet of the chamber, and in that the second heat exchanger and the coolant circuit of the heat pump circulate the coolant in a transcritical cycle so that air is heated with a temperature differential greater than 40°C, in particular greater than 60°C, and to a high target temperature Tc, greater than 120°C, upstream of the drying rack, air as external fluid (Fe) transferring heat as it passes the drying rack, with a large temperature differential between air as the external fluid upstream of the drying rack and air as the external fluid downstream of the drying rack. - first and second heat exchangers adapted to exchange heat respectively with the source fluid (Fs) located in the vicinity of the first heat exchanger and the external fluid (Fe) located in the vicinity of the second heat exchanger, each of said first and second heat exchangers having an inlet and an outlet, - a coolant selected from among a hydrofluorocarbon coolant and a hydrofluoroolefin coolant, - a coolant circuit suitable for circulating the coolant between the first and second heat exchangers, said coolant circuit comprising a compression unit having an inlet connected to the outlet of the first heat exchanger and an outlet connected to the inlet of the second heat exchanger, and an expansion unit having an inlet connected to the outlet of the second heat exchanger and an outlet connected to the inlet of the first heat exchanger, - a chamber having an inlet and an outlet, - a treatment system located in the chamber, the treatment system is a drying rack intended to receive a material to be dried, - a circuit of external fluid, suitable for circulating air as the external fluid (Fe) successively in the vicinity of the second heat exchanger and in the vicinity of the treatment system, said external fluid circuit being further adapted to circulate air as the external fluid downstream of the treatment system, as the source fluid, in the vicinity of the first heat exchanger, - arranging the material on the drying rack, - circulating air as the source fluid and the external fluid (Fe) between the inlet and the outlet of the chamber, air circulating successively in the vicinity of the second heat exchanger, in the vicinity of the drying rack and in the vicinity of the first heat exchanger, - circulating the coolant,