Device and method for heating and cooling a compartment of a motor vehicle

Device for heating and cooling a compartment of a motor vehicle powered by an internal combustion engine, said device comprising:

• a coolant circuit including a compressor, an ambient heat exchanger, at least one expansion device, an interior air heat exchanger, and an exhaust heat exchanger that is heatable by exhaust gases from the internal combustion engine, a coolant guided during a heating operation through the compressor and, while giving off heat, through the interior heat exchanger connected downstream from the compressor;
• a valve switchable from a heating operation position and a cooling operation position;
• wherein, when the valve is switched to the heating operation position, said compressor, said interior heat exchanger, said at least one expansion device, said ambient heat exchanger, and said exhaust heat exchanger are connected in series such that the coolant is (i) expanded in said at least one expansion device to a temperature below an intake temperature of the coolant into the compressor, (ii) exposed in said ambient heat exchanger to warmer ambient air when said ambient heat exchanger is not bypassed, (iii) heated directly in said exhaust heat exchanger by the exhaust gases from said internal combustion engine, said exhaust gases piped continuously through said exhaust heat exchanger, and (iv) compressed in said compressor;
• and further comprising a bypass valve operatively disposed between said at least one expansion device and said ambient heat exchanger wherein during said heating operation said bypass valve is operative to bypass said ambient heat exchanger when the coolant is expanded to a temperature that is below a temperature of ambient air that flows through said ambient heat exchanger and below a sublimation point of water in the ambient air, thus preventing formation of ice on said ambient heat exchanger, and wherein said exhaust heat exchanger is not bypassable in said series heating circuit by said bypass valve;
• wherein, when the valve is switched to the cooling operation position, said compressor, said ambient heat exchanger, said at least one expansion device, and said interior heat exchanger are connected in series such that the coolant is (i) exposed in said ambient heat exchanger to colder ambient air, (ii) expanded in said at least one expansion device to a temperature below a compartment air temperature and (iii) a compartment air is exposed to the coolant in said interior heat exchanger.