C. RULES OF THUMB FOR AN INITIAL ESTIMATE OF EQUIPMENT SIZE
The following are approximate values that may be used to estimate the size of the primary wood heating equipment. Once a project is given the “go ahead” an exact heat loss should be calculated according to ASHRAE Fundamentals or Manual J methods to ensure correct sizing. Over-sizing equipment leads to excessive first cost, inefficient operation, and increased emissions. There are software packages that calculate an accurate heat loss value based on the detailed construction of the building. An example is Elite Software’s RHVAC program. DECTRA CORPORATION can run an in-depth heat loss analysis for a fee.
To learn more about Elite Software RHVAC or to purchase a software license visit: http://www.elitesoft.com/
COMMERCIAL HEAT LOSS: Calculating the heat loss for commercial buildings can be more complicated than for residential structures because the building type and application vary significantly. The easiest way to get a handle on heat loss figures for a commercial facility is to use a computer software package. A good commercial heat loss packages is Elitie Software’s CHVAC program.
To learn more about Elite Software CHVAC or to purchase a software license visit: http://www.elitesoft.com/
RESIDENTIAL HEAT LOSS EXCLUDING VENTILATION:
Old/Poorly Insulated House Uninsulated basement
Newer House Insulated Basement
Energy Efficient House Insulated Basement
Above Grade Floor Area (BTUH/sq. ft.) Below Grade Floor Area (BTUH/sq. ft.)
25 to 35
13 to 24
8 to 15
18 to 30
10 to 20
8 to 12
RESIDENTIAL VENTILATION:
In newer, tighter energy efficient houses, mechanical ventilation is required at a generally accepted rate of 15 cfm per person. The following should be added to the heat loss for newer houses, but not added to the heat loss of older houses (unless the older house has been reinsulated and tightly sealed against air leakage).
Heat Recovery Ventilator Not Used Heat Recovery Ventilator Used 6,000 BTUH/person 3,000 BTUH/person
For more information on HRV products visit: http://www.vanee-ventilation.com/ http://residential.fantech.net/
6
Hydronic System Design Manual ©DECTRA CORPORATION - March 2013
Made with FlippingBook - professional solution for displaying marketing and sales documents online