How do you select and size HVAC equipment and components for different applications?

1 HVAC load calculation

The first step in HVAC systems design calculations is to determine the HVAC load, which is the amount of heating or cooling required to maintain the desired indoor temperature and humidity. HVAC load calculation involves estimating the heat gain or loss from various sources, such as solar radiation, outdoor air, occupants, lighting, appliances, and infiltration. HVAC load calculation can be done using manual methods, such as tables and charts, or software tools, such as Carrier HAP or Trane TRACE.

2 HVAC equipment selection

The next step in HVAC systems design calculations is to select the appropriate HVAC equipment, such as boilers, furnaces, heat pumps, chillers, air handlers, and fans. HVAC equipment selection depends on several factors, such as the HVAC load, the type of fuel, the availability of space, the noise level, the maintenance requirements, and the cost. HVAC equipment selection can be done using manufacturers' catalogs, performance curves, and specifications.

3 HVAC component sizing

The final step in HVAC systems design calculations is to size the HVAC components, such as ducts, pipes, valves, pumps, coils, filters, and dampers. HVAC component sizing ensures that the HVAC equipment can deliver the required heating or cooling to the indoor spaces, while minimizing the pressure drop, friction loss, and energy consumption. HVAC component sizing can be done using engineering formulas, design guides, and software tools, such as ASHRAE Duct Size or Elite Software.

4 HVAC design criteria

HVAC systems design calculations should follow the HVAC design criteria, which are the standards and guidelines that specify the performance and quality of HVAC systems. HVAC design criteria include the indoor and outdoor design conditions, such as temperature, humidity, and airflow; the thermal comfort and indoor air quality requirements, such as ASHRAE 55 and ASHRAE 62.1; and the energy efficiency and environmental regulations, such as ASHRAE 90.1 and LEED.

5 HVAC design documentation

HVAC systems design calculations should be documented and communicated in the HVAC design documentation, which are the drawings and reports that describe the HVAC systems. HVAC design documentation include the HVAC schematics, which show the layout and connection of HVAC equipment and components; the HVAC plans, which show the location and size of HVAC ducts and pipes; the HVAC schedules, which list the HVAC equipment and component specifications; and the HVAC calculations, which show the HVAC load, equipment selection, and component sizing.

6 HVAC design review

HVAC systems design calculations should be reviewed and verified in the HVAC design review, which is the process of checking and evaluating the HVAC systems. HVAC design review involves comparing the HVAC design documentation with the HVAC design criteria, identifying any errors or discrepancies, and making any necessary revisions or corrections. HVAC design review can be done by the HVAC designer, the HVAC contractor, the building owner, or a third-party consultant.