NOVELTY - The condenser includes an AC/DC transformer, a pump comprising Peltier plates (4) connected to the transformer and an evaporation unit with at least one fan (2) and a radiator (1). Thermally conducting filler is used to bond the plates to the radiator and the latter to a heat transmission block containing a condensation tube.    USE - For diagnosing bronchopulmonary processes such as inflammations, infections, allergies and neoplasias.    ADVANTAGE - No compressor or potentially environmentally harmful coolants are used. Exhaled air is collected in an open circuit, rather than in a closed one, allowing the exhaled air to escape into the atmosphere. The condenser can also be incorporated into a ventilator.    DETAILED DESCRIPTION - A thermoelectric condenser for vapour in exhaled air comprises a power supply, a thermoelectric pump, a condensation tube and a respiration circuit. The power supply comprises an AC/DC transformer connected to the thermoelectric plates. The pump is operated using the Peltier effect and comprises thermoelectric plates and an evaporation unit with at least one fan and a radiator, the plates being bonded to either side of the latter via thermally conducting filler. The opposite sides of the plates to the radiator are bonded via thermally conducting filler to the inner side of the heat transmission piece formed by a metal block containing the condensation tube. Temperature control is achieved using a digital thermometer with a thermal probe inserted into an opening in the metal block. The condensation tube comprises two parallel vertical cylinders (5, 6) made from crystal and inserted into the metal block. The lower ends the tubes are connected via a pressure-tight piece or collector, whilst the upper ends are each capable of receiving an adaptor for a standard tube. The respiration circuit supplies exhaled air to the condensation tube and this air is prevented from flowing back in the opposite direction by check valves. The circuit can be connected directly to the patient via e.g. a mouthpiece or mask, or it can incorporated into the exhalation branch of a respiratory circuit in a ventilator.    DESCRIPTION OF DRAWING(S) - Figures 1a and 1a show the condenser in horizontal and vertical positions.    Radiators (1)    Fans (2)    Thermal insulation (3)    Peltier plate (4)    Crystal cylinder for condensation tube (5)    Crystal cylinder for temperature probe (6)    Support (7)    Thermostat and switches (8)