A flameless heater includes a diesel engine, a hydraulic or electric load that is powered by the diesel engine thereby generating heat, a heat exchanger that transfers heat to air flowing through the air from the flameless heat source, and possibly other heat exchangers for heating the air flowing therethrough with engine coolant and/or with exhaust gases. The system may be operated to maintain relatively high load on the engine for at least the majority of the time so as to reduce or negate the need for parked regeneration. The system may also control airflow through the system and possibly other system parameters to obtain a given setpoint such as a given discharge air temperature. In one embodiment, airflow through the system is controlled by louvers under the power of an electric motor or other actuator controlled by the system's controller.

A mobile heating system is disclosed. In one embodiment, the system includes an enclosure defining a plenum that houses a fan and an internal combustion engine. The heating system also includes a hydraulic circuit including a hydraulic pump operably coupled to the internal combustion engine and a first heat exchanger located in the plenum and in fluid communication with the hydraulic pump. The hydraulic circuit also includes a hydraulic motor operably coupled to the fan wherein the hydraulic motor is in fluid communication with and driven by the hydraulic pump. A first valve is disposed between the hydraulic pump and the heat exchanger and is configured to restrict fluid flow and to increase a fluid pumping pressure of the hydraulic pump. A second valve is located upstream of the first valve and is configured to selectively direct hydraulic fluid between the first valve and the hydraulic motor.