Cooling Injection

Cold water, generally from a chiller, can be injected efficiently and economically with the SMART Water Glycol System, replacing the need for a separate cooling coil.

Cool injection is used when the energy recovery system is unable to maintain the supply air set point by rejecting heat to the exhaust airstreams alone. Due to the supply air set point being lower than the exhaust air temperature in most non winter conditions, cool injection is utilized for most of the summer cooling mode conditions or while in the traditional economizer range. The controller will automatically bypass the exhaust coils when energy cannot be effectively recovered from the exhaust air, (typically in the economizer range).

Cool injection is best used in dryer climates when the cooling load is mainly sensible, with little to no latent load. This feature is commonly used in conjunction with heat injection, which results in a single coil configuration. This single coil configuration means that the system manages the full building load throughout the year and can greatly reduce the size of the AHUs and can eliminate large amounts of initial costs for the buildings HVAC system. Another added benefit of the single coil configuration is the reduced energy costs associated with lower air side pressure drop and pump energy costs when compared to having separate coils for energy recovery, cooling, and heating.




The SMART Water Glycol system allows up to 18 airstreams on one skid. Each airstream can be individually controlled to its own supply air set point giving design engineers unparalleled flexibility on their system design. The main pump skid controls the amount of glycol that is pumped through the supply and exhaust coils to maintain the individual supply air set points. Plates and frame heat exchangers are used for water-to-water heat exchange. Regardless of which options are chosen, HPT has industry-leading solutions for your project.


HPT engineers are always available to assist with system designs to achieve maximum energy recovery and to meet the building needs. With state-of-the art runaround glycol performance selection and industry-leading controls, the SMART Water Glycol system is the right solution for you.  For quick turnaround solutions to your energy recovery needs, reach out to