Compressors are used with industrial gas for alternative fueling, primarily CNG and Hydrogen. Hydro-Pac compressors are well suited to a number of high-pressure fueling strategies including:


  1. Direct fill: the compressor fills the tank directly. With some dispensers a small buffer may be required.
  2. Cascade fill: the compressor fills individual storage cylinders, which are then equalized sequentially with the vehicle.
  3. Low-pressure storage, high-pressure fill: the compressors are sized to utilize inlet storage at 3,000 to 6,000 psi (20 to 40 MPa) to fill a high-pressure vehicle tank at 6,000 to 14,000 psi (40 to 97 MPa). This eliminates the need for high-pressure storage tanks yet allows the compressors to displace a large quantity of gas when operating with a higher inlet pressure during the vehicle fill.
  4. Scavenge scenarios on multiple storage tank installations: the compressors scavenge gas from the lower pressure tanks and quickly fill the higher-pressure tanks. This allows faster vehicle fill times. This is usually used in conjunction with the low-pressure storage, high-pressure fill strategy to maximize gas usage.
  5. Parallel/Series compressor arrangements: two or more single stage units act in parallel to move large quantities of gas when pressure differentials are low and then switch to series operation when pressure differentials increase.
  6. In many instances, careful selection of the compressors will minimize the cost of the gas storage tanks by reducing the amount of storage required and the pressure rating of that storage. Please contact a Hydro-Pac sales engineer to discuss options.