Flameless heating system

Abstract

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.

What is claimed is: 
     
         1 . A mobile heating system comprising:
 a. an enclosure supported by a mobile chassis, the enclosure defining an air plenum having an air inlet and an air outlet;   b. a fan disposed in the air plenum, the fan being configured to move an air flow stream from the air inlet to the air outlet of the enclosure;   c. an internal combustion engine disposed in the air plenum, the internal combustion engine having an output shaft; and   d. a hydraulic circuit including:
 i. a hydraulic pump operably coupled to the output shaft of the internal combustion engine; 
 ii. a first heat exchanger located in the enclosure air plenum and in fluid communication with the hydraulic pump, the first heat exchanger being configured to transfer heat from fluid in the hydraulic circuit to the air flow stream; 
 iii. a hydraulic motor operably coupled to the fan, the hydraulic motor being in fluid communication with and driven by the hydraulic pump; 
 iv. a first valve disposed between the hydraulic pump and the heat exchanger, the first valve being configured to resist fluid flow and to increase a fluid pumping pressure of the hydraulic pump; and 
 v. a second valve upstream of the first valve, the second valve being configured to selectively direct hydraulic fluid between the first valve and the hydraulic motor. 
   
     
     
         2 . The mobile heating system of  claim 1 , further comprising a control system configured to operate the second valve to maintain a temperature set point of the air flow stream. 
     
     
         3 . The mobile heating system of  claim 1 , further comprising a third valve upstream of the second valve, the third valve being configured to bypass hydraulic fluid around the first and second valves to the first heat exchanger. 
     
     
         4 . The mobile heating system of  claim 3 , further comprising a fourth valve in parallel with the first valve, the fourth valve being configured to bypass hydraulic fluid around the first valve to the first heat exchanger. 
     
     
         5 . The mobile heating system of  claim 4 , wherein the first valve, the second valve, the third valve, and the fourth valve are provided in a single manifold block. 
     
     
         6 . The mobile heating system of  claim 1 , further comprising a second heat exchanger located in the enclosure air plenum, the second heat exchanger being configured to transfer heat from an engine exhaust air stream to the heating air flow stream. 
     
     
         7 . The mobile heating system of  claim 6 , wherein the second heat exchanger includes a single tube having a plurality of offset straight sections. 
     
     
         8 . The mobile heating system of  claim 1 , further comprising a third heat exchanger located in the enclosure air plenum, the third heat exchanger being configured to transfer heat from an internal combustion engine coolant to the heating air flow stream. 
     
     
         9 . The mobile heating system of  claim 1 , wherein the internal combustion engine is controlled to maintain a generally constant rotational speed. 
     
     
         10 . The mobile heating system of  claim 2 , wherein the control system further includes a user interface. 
     
     
         11 . The mobile heating system of  claim 10 , wherein the user interface is configured to override the position of the first valve to a set position.