I bought the APEC (Automated Procedures for Engineering Consultants) APEC programs as memorabilia when it folded up in 2002. APEC was founded in 1965. The APEC HCC-V (Heating & Cooling Calculations version V) program can still be used. At SOM it was used until 2002.
I was able to install and run the HCC-V program on a 32-bit computer but not the 64-bit computer. Does anyone know how to fix a 32-bit program to run on a 64-bit computer. I have the source code.
HCC-V is based on the TETD method. If you don't know what a decrement factor is, enter 0.5 (the range 0 to 1). For an office bldg that closes at 6 PM make the time lag 3 hours (HCC assumes the peak hour is 3 PM) so that it affects the building during office hours.
You can find information about the APEC HCC-V program in the website
http://bepan.info/
under X - HVAC-Programs
Varkie Thomas