Johnson Refrigerated Truck Bodies has increased thermal efficiency and structural stability of its truck bodies with a new high-pressure polyurethane foam insulation system.
Facility upgrades have been completed, and Johnson is using the new foam insulation system in all truck body designs as of the end of March 2012.
Thermal performance of a truck body is largely affected by the insulation value of the foam material used in the production of wall, floor, and ceiling panels. Insulation value is measured by a material’s ability to resist heat transfer; this is known as the R-value.
Calculated R-values measure the amount of Btus that transfer across a one-inch thick by one-foot-square section of material and have a minimum temperature differential of one degree Fahrenheit across the thickness. R-values for foams with equivalent density to Johnson’s polyurethane foam, range from R-5.6 to R-7.8. Johnson’s insulation R-value is R-7.5 per inch of thickness. Higher R-values in insulated transportation equipment indicate better insulating properties, which result in lower operating costs and greater protection for temperature-controlled goods.
The combination of new high-pressure injection equipment and improved foam chemistry offers these benefits:
•Higher R-value—5% greater R-value than Johnson equipment produced with the previous insulation system. This is mainly due to a tighter cell structure in the foam insulation. The new high-pressure foam injection equipment provides a better control of mix ratios and chemical temperature, both of which affect the consistency of cell structure.
•A 9% gain in structural stability of wall and ceiling panels. Injection rates of the new equipment will increase three times the current rate, allowing the foam chemistry to properly and fully react within the panels for a more consistent thermal and structural performance throughout the truck body.
•Thermal degradation as a result of “outgassing” is reduced due to the more stable blowing agent used in the new system. Additionally, the tighter cell structure and more uniform cell shapes of the new foam further reduce the outgassing potential. Although Johnson truck bodies have historically had very low outgassing issues because of their completely sealed, rivet-free designs, the occurrence of outgassing is even less with the new foam insulation system.
•Operational efficiency gains for truck fleets—Higher thermal performance from beginning to end results in reduced consumption of electricity and fossil fuels to power the truck body refrigeration systems.
For more information, visit www.johnsontruckbodies.com.
