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Cooling load calculation: Why is it an important standard and how does it work?

Cooling load calculation: Why is it an important standard and how does it work?

To properly design and install any type of efficient forced-air heating and cooling system, MEP engineers must implement certain evaluations that factor in building size and occupancy limits, among other variables, for what’s known as the cooling load calculation.

Load calculation is used across the industry to determine the adequate size of an HVAC system to ensure it will suitably cool and heat an entire structure. This calculation can be done before initial installation or when upgrading or adjusting pre-existing systems.

Factors and formulas in determining cooling load

Though the basic formula for load calculation is quite simple, there are many factors and complex calculations that MEP engineers must account for when determining the precise load calculation. Some of these include:

  •  Amount, size and efficiency of windows in a structure.
  • Local weather (including temperature patterns and humidity).
  • The structure’s orientation to the sun.
  • Air-leakage rates of the structure.
  • Air-leakage rates of the ducting systems in place, if applicable.
  • Quality of insulation used in the structure.
  • Lighting systems and other appliances that produce additional heat.
  • The average number of occupants.

The most common and simple formula used in the HVAC trade utilises the following three factors to determine a general total load of a building (expressed in British Thermal Units (BTU).

1 occupant = 100 BTU

1 window = 1000 BTU

1 exterior door = 1000 BTU

The importance of cooling load for projects and building inspections

Before making the decision to hire and contract with an MEP consultant, it’s always recommended to utilise resources like a simple online load calculator to get a rough idea of what to expect insofar as total cooling load for your next project.

For those of us (particularly those working in commercial buildings), strict regulations imposed by the latest EPB Regulations (England and Wales) mean that successful building inspections meet certain green standards that consider the health effects and energy efficiency of heating and cooling systems. Knowing your cooling load and regular maintenance of your HVAC system will ensure your building is up to code. Here you can watch an example of how the cooling load is determined in a residential setting.

What do cooling load inspections involve and what are their benefits?

HVAC system inspections by accredited air conditioning energy assessors are intended to improve mechanical efficiency, regulate energy consumption, moderate operational costs and, most importantly, cut carbon emissions. During an inspection, the energy assessor will determine how (if applicable) the operation of an existing system can be perfected or may otherwise suggest upgrading obsolete, inefficient or oversized systems with newer, up-to-date air conditioners and heaters.

Proper inspection, maintenance and cleaning of an HVAC system, regardless of size, allows for the system to provide a more healthy and comfortable environment for building occupants. By ensuring the safety of equipment and regularly tracking and monitoring cooling loads for efficiency, load calculation remains one of the most important factors in ensuring a system works adequately and adheres to essential energy and health standards.

 

 

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