Civil Engineering and Architecture

 

Energy Systems

Design conditions

  • Know the outdoor conditions of your local area.

  • Know the desired indoor conditions of the building.

Areas calculations

  • Calculate the total area of all walls only (no windows and no doors.)

  • Calculate the total area of all windows.

  • Calculate the total area of all doors.

  • Calculate the area of the roof.

  • Pick the desired material for walls, windows, doors, and roof. 

Heat gain/loss calculations

Summer heat gain consists mainly of four (4) major parts:

  • Solar heat gain through walls, windows, door and roofs.

  • Occupants’ heat gain.

  • Cold mass heat gain from different things, such as equipment, machines.

  • Lighting heat gain.

There are also factors, such as infiltration; shaded windows; building latitude and altitude; time of maximum exposure; and prevailing winds. These factors are not considered in these particular calculations.

Winter heat loss consists mainly of 2 major parts:

  • Heat loss through the building structure, such as the walls, windows, doors and roof.

  • Required additional heating for the incoming infiltrating air.

Heat Gain or Loss:

  • Q = A U /\T

  • Q = Total cooling/heating load in BTU/hr

  • A = Area under investigation in ft. sq.

  • U = Coefficient of heat conductivity in BTU/ hr.ft.sq.0F

  • /\T = Difference in temperature between outside and inside conditions in 0F

  • U = 1/R

There is another value called the R value, which is the coefficient of heat resistance in (ft. sq. hr. 0F) /BTU. Note that R = 1/U

Insulation:

InsulationR-Values