The size and capacity of the refrigeration system needed for an HVAC project can be determined by calculating the total cooling load of the space. This can be done by measuring the size of the space, the number of windows, the insulation levels, and the climate of the area. Additionally, the type of equipment being used and the number of occupants in the space should be taken into consideration. Once the total cooling load is calculated, the size and capacity of the refrigeration system can be determined by comparing it to the manufacturer’s specifications.