Commonwealth provided design for new boiler HVAC equipment and hot water circulation system for the TransCanada Mooreland Oklahoma Compressor Station. The plant upgraded the existing boiler from steam to hot water which required design of a new boiler, associated electrical and controls, and mechanical circulation system for both plant heat and HVAC, as well as equipment process loads for engine jacket water heaters. A critical step involved calculating heat transfer into the natural gas compressor jacket water to the extent of ensuring a maximum allowable warmup time before starting the compressor. In addition, pipe routing, locating the new hot water coil for the air handling unit, new hot water unit heaters and jacket water heat exchangers was provided. Lastly, consideration was given to the Owner required water/glycol mixture for sizing equipment, heat transfer and fluid viscosity in calculating pumping power requirements.